A Publication of Glidewell Laboratories • Volume 6, Issue 1
Dr. Gordon Christensen
The Dangers of “Gray-Market”
and Counterfeit Dental Products
Dr. Gregg Helvey Takes a Closer Look
How to Spot Digitally Edited Photos
Dr. David Hornbrook Discusses
Esthetics, Lasers and Digital Dentistry
Dr. Michael DiTolla’s
9 Dr. DiTolla’s Clinical Tips
Featured in this issue is the IOS FastScan ® , a new
digital impression system that has been clinically
tested at Glidewell over the past three years. Also
highlighted are Clear-Lock Retainers for Life and
the aveoTSD ® Health Professional Patient Sizing Kit,
both from Glidewell Laboratories. Finally, we have
what may be a way to predictably bond BruxZir ®
restorations: OptiBond XTR.
14 Are You Using “Gray-Market” or
Counterfeit Dental Products?
It’s no secret that dentists love to save money. But, as
Dr. Gordon Christensen discusses, purchasing steeply
discounted dental materials when looking to cut
costs may be a gray area you want to avoid. Learn
the dangers of purchasing gray-market and counterfeit
dental products. Plus, Dr. Christensen explains
how to spot gray-market and counterfeit products
and outlines measures you can take to avoid falling
victim to this illegal, yet lucrative, business.
21 Monolithic Versus Bilayered
Restorations: A Closer Look
Advancements in dental ceramics have forever
changed dentistry. Monolithic restorations, such as
IPS ® e.max and BruxZir, are one such game changer.
Dr. Gregg Helvey compares IPS e.max monolithic
crowns to bilayered PFM restorations and highlights
the characteristics of each.
32 One-on-One with Dr. Michael DiTolla:
Interview of Dr. David Hornbrook
Esthetic dentistry authority Dr. David Hornbrook is
one of my clinical mentors and has been ever since I
took his courses at LVI. I checked in with him to see
which modern-day materials he considers the gold
standard for anterior restorations and to gauge his
thoughts on digital impressions, monolithic restorations
and diode lasers. Does this esthetic dentistry
expert believe in same-day dentistry, with crowns
milled chairside in the dental office? I got the answer.
NEW! Read Chairside on the go using your smartphone.
Thanks to a simpler design, you can now
enjoy your favorite recurring columns from virtually
anywhere. Visit www.chairsidemagazine.com from
your smartphone to see just how easy it is.
46 Detecting Computer-Enhanced
When it comes to dental photography and pictures
of products, patients and medical conditions, many,
if not all, pictures have been edited. Maybe it’s done
to hide a crack or whiten a smile, but how can
you be sure what you are seeing is real? Dr. Ellis
Neiburger and Yehonatan Frandzel discuss the many
ways to detect digital photo enhancement. They
reveal that, despite recent developments in digital
imaging in dentistry, there are telltale signs a photo
has been edited.
53 Periodontal Photo Essay:
Is Closed-Flap Crown Lengthening a
Biologically Sound Procedure?
In this photo essay, Dr. Daniel Melker discusses his
feelings on closed-flap crown lengthening. With the
drop in prices of hard tissue lasers, this procedure will
no doubt become more popular among GPs. Rather
than laying a flap and directly observing the bone
that is being reshaped, closed-flap crown lengthening
relies strictly on feel, hence the controversy.
63 Dr. DiTolla’s Patient Product Review
In the last issue of Chairside magazine, I discussed
how men and flossing don’t belong in the same sentence.
Touching again on this topic, I introduce you
to a unique toothpick by Ultradent called Opalpix .
While Opalpix doesn’t replace the benefits of flossing,
it is my best hope for men who appear to be
allergic to floss.
Jim Glidewell, CDT
Michael DiTolla, DDS, FAGD
Mike Cash, CDT
Michael DiTolla, DDS, FAGD
Senior Copy Editor
Jennifer Holstein, Eldon Thompson
Graphic Designers/Web Designers
Jamie Austin, Deb Evans,
Joel Guerra, Phil Nguyen, Ty Tran
Sharon Dowd, Kevin Keithley,
James Kwasniewski, Sterling Wright
Wolfgang Friebauer, MDT
If you have questions, comments or complaints regarding
this issue, we want to hear from you. Please e-mail us at
firstname.lastname@example.org. Your comments may be
featured in an upcoming issue or on our website:
© 2011 Glidewell Laboratories
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shall CAUTION: not be When used viewing for advertising the techniques, or product procedures, endorsement theories purposes. and materials
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terials specific that treatment are presented, for patients you and must exercise make personal your own professional decisions about judgment
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Chairside is a registered trademark of Glidewell Laboratories.
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I have been hearing about the death of PFMs for the past
15 years. In fact, the PFM department managers here at the
lab always have a good laugh when I show them a dental
journal with an article by a metal-free clinician predicting
the demise of PFMs within the next three to five years.
While a metal-free style of practice can certainly work for
dentists who passionately believe in metal-free dentistry,
the numbers at the lab tell another story: PFMs aren’t dead.
Most dentists are satisfied with PFMs and continue to prescribe
them in large numbers. After all, PFMs are versatile
and can be used for single units, multiple units and even
roundhouse bridges. Those who want to pretty it up can
always cut a facial shoulder for a porcelain margin or use
an esthetic PFM, such as Captek , in the esthetic zone.
PFMs have long been the workhorse restoration, but then
one day something happened … and that something was
BruxZir ® Solid Zirconia. For 10 years I begged R&D for
a cast gold crown in a shade A2. Jim Glidewell was bugging
them to make a full-contour zirconia crown, just to
see what it would look like. BruxZir got both of us off
From the day it launched, BruxZir was a niche product. It
was meant to be an esthetic replacement for cast gold and
metal occlusals, but I started using it to replace broken
PFMs (because those patients had already destroyed
that type of restoration). All of a sudden, dentists started
placing BruxZir everywhere, showing preference for
this high-strength, cementable, monolithic, tooth-colored
material, despite it being “more brawn than beauty.”
The popularity of BruxZir continues to grow, with a recent
sales record totaling 7,300 crowns & bridges in one week!
That makes BruxZir the fastest growing product in the
40-year history of Glidewell Laboratories.
So while PFMs are not dead, the PFM department no longer
laughs at these jokes. We can use BruxZir to do virtually
anything that can be done with a PFM, including
roundhouse bridges. These monolithic restorations seem
poised to replace their bilayered brethren; however, the
change may be measured in decades, rather than years.
Yours in quality dentistry,
Dr. Michael C. DiTolla
Editor- in-Chief, Clinical Editor
Editor’s Letter 3
Letters to the Editor
Dear Dr. DiTolla,
I have really enjoyed your articles and
video presentations over the years. They
are very informative and helpful.
I have a question regarding your success
rate with the Milestone Scientific
STA System. I have been using it now for
more than a year, and it seems to be hit or
miss, just like the mandibular block. I love
it when it works, but I find it very annoying
when I have to go back and do a block.
I wonder what you might be doing differently.
I use 4 percent articaine with
1:100,000 EPI and usually deposit the
anesthetic for 15 seconds after I have
reached the PDL (about one-third of a
carpule). I have tried both buccal and
lingual placement, as well as mesial and
distal. Many times it does not even get
to three bars on the graph LED. Any
thoughts you may have as to why this is
happening would be greatly appreciated.
– Jeffrey Olson, DDS
Thanks for the kind words! I did
have a period of time where my
effectiveness with the STA System
went down, albeit very slowly.
My initial enthusiasm for the unit
slowly waned and then, luckily, the
unit stopped working completely. I
sent it back to Milestone Scientific,
and they sent me a loaner to use in
the interim. It was like magic! I was
getting the PDL alert on every single
tooth! I was in heaven. I realized
that the problem was with my unit.
When my STA System came back I
was reluctant to return the loaner.
I kept it in the office for a week, until
I verified that my old one was working.
My suggestion is that you send
your unit in for some maintenance to
ensure it’s working properly.
I usually start in the buccal furcation
with an extra-short needle, and if I
get the PDL alert there I am usually
good. If there is perio involvement, I
usually go to the ML corner, where it
is the norm to get the PDL alert, and
then I also go to the DL corner. If the
patient is phobic or sensitive, I do all
four corners. Sometimes I have to go
back in with a little more in the PDL,
but I have never had to go back and
give a block. I usually see patients
whose last dentist couldn’t get them
numb with a block, and I’m able to
with the STA System.
Keep me apprised of your experience
because I recommend the
STA System to everyone.
Dear Dr. DiTolla,
I recently discovered your Rapid Anesthesia
Technique on YouTube, and I have tried
it a few times. What are some of the postop
complaints, and how do you address
them? Thank you for your help.
– Seada Damiano, DDS
I don’t get that many side effects now
that I use the STA System to deliver
the Septocaine ® . When I was doing
the Rapid Anesthesia Technique using
a hand syringe, I used too much
pressure, which caused some tearing
of the PDL and resulted in the tooth
being sensitive to percussion or biting
in some cases. The STA System
has eliminated the speed and pressure
issues, so I don’t see that anymore.
Post-op complaints are almost
nonexistent now — nowhere near
where they used to be when I was
routinely giving lower blocks.
Thank you for your prompt reply. I really
appreciate it. I have tried the technique
(manually) about six times. Yesterday a
patient I had seen about a week ago for
an occlusal on tooth #31 came back and
complained of pain in the gingival area.
The tooth was fine on percussion. Maybe
I used too much pressure or too much
solution. I think this technique is fantastic,
and I will look into the STA System.
Thanks again, and have a great day!
I’m not an STA System salesman,
but when I started using it my confidence
with the technique really
took off. I had a patient come in last
week who left her dentist of 15 years
because he couldn’t get her lower
molar numb on two consecutive
appointments to finish a crown prep.
I used to dread these types of patients,
but I actually look forward to
them now because I have been able
to anesthetize all of them so far. In
those cases, I inject in the furcation
and the buccal and lingual sulcus,
but it has always worked. You truly
become their hero.
Dear Dr. DiTolla,
I wanted to thank you for the excellent
veneer video you made. I learned a lot:
putty-wash index, the Rapid Anesthesia
Technique and fixing alignment before
depth cutting! Those were big, and I feel
like I became a better dentist from watching
One question: When you use a putty-wash
index of the wax-up, do you use lubricant?
I broke a few wax-up teeth (glued them
back easily though) when I took my putty
index. The impression material sucked up
all the moisture from the model and adhered
to certain waxed teeth on the model.
– Ruslan Korobeinik, DDS
White Plains, N.Y.
I have done that as well, although
once the putty-wash matrix is done,
I really don’t need the wax-up anymore.
Of course, you could always
have the lab make a duplicate stone
model of the wax-up, making it easier
to work with. I hope that helps!
Dear Dr. DiTolla,
As usual, I read Chairside magazine cover
to cover as soon as I received it (I can’t say
the same for some of the other periodicals
I receive). In the most recent issue, I was
glad to see that you mentioned Glidewell
Laboratories is a CEREC ® Connect laboratory.
(I don’t think it has been properly
advertised, and Glidewell is very good at
advertising.) This might be a good topic
for a future article.
I wrote an article on the subject that has
not yet been published, and I am attaching
it for your opinion. I hope you find the time
to send me some feedback.
– Carlos Boudet, DDS, DICOI
West Palm Beach, Fla.
Thanks for the kind words. I would
love to review the article you sent.
Our only requirement is that it is accompanied
by outstanding clinical
photography! I look forward to reading
Dear Dr. DiTolla,
Congratulations on your latest issue of
Chairside. I very much enjoyed the article
“Simplifying Lab Communication: The
Dental Midline Position, Incisal Cant and
Incisal Horizontal Plane” by Dr. Leendert
Boksman. The article seems uniquely appropriate
when one looks at the front cover
and observes and absolutely beautiful
young lady with her upper midline at least
half a tooth to the left of her facial midline
and her left eye fully 6 mm higher than
her right eye. Literally everyone has some
facial asymmetry, including Dr. Boksman
whose glasses have a pronounced uphill
slant to the left. The point is that our stepbrothers,
the cranial osteopaths, and the
rather few practicing cranial orthodontists
have shown that they are able to produce
dramatic improvement and, occasionally,
correction of these asymmetries. The
others simply say that such asymmetry is
“acceptable” (which it must be if one does
not know or understand how to correct it).
I don’t know if this information would be
of interest to Chairside magazine, as it is
more of an orthodontic concern, but the
article in your magazine was absolutely
fascinating to me, and I intend to order
several Onebite facial plane relators
immediately. Thank you so much!
– Gerald W. Spencer, DDS
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Letters to the Editor 5
Michael C. DiTolla, DDS, FAGD
Dr. Michael DiTolla is a graduate of University of the Pacific Arthur A. Dugoni School of Dentistry.
As Director of Clinical Education & Research at Glidewell Laboratories in Newport Beach, Calif.,
he performs clinical testing on new products in conjunction with the company’s R&D Department.
Glidewell dental technicians have the privilege of rotating through Dr. DiTolla’s operatory and
experiencing his commitment to excellence through his prepping and placement of their restorations.
He is a CR evaluator and lectures nationwide on both restorative and cosmetic dentistry. Dr. DiTolla has
several clinical programs available on DVD through Glidewell Laboratories. For more information on
his articles or to receive a free copy of Dr. DiTolla’s clinical presentations, call 888-303-4221 or e-mail
Gordon J. Christensen, DDS, MSD, Ph.D
Dr. Gordon Christensen is a practicing prosthodontist in Provo, Utah. His degrees include DDS,
University of Southern California; MSD, University of Washington; and Ph.D, University of Denver. He
is a Diplomate of the American Board of Prosthodontics; Fellow and Diplomate of the International
Congress of Oral Implantologists; Fellow of the Academy of Osseointegration, American College of
Dentists, International College of Dentists, American College of Prosthodonists and Royal College of
Surgeons of England; Honorary Fellow of the AGD; and Associate Fellow of the AAID.
Drs. Gordon and Rella Christensen are cofounders of the nonprofit Gordon J. Christensen CLINICIANS
REPORT ® (formerly CRA ® Newsletter). Contact Dr. Christensen at 801-226-6569 or email@example.com.
Yehonatan L. Frandzel, FPH
Yehonatan Frandzel is an architect and designer based in Haifa, Israel. He is a graduate of Technion-
Israel Institute of Technology, where he studied in the Faculty of Architecture and Town Planning.
Yehonatan is head of Architectural Visualization, 3-D Modeling and Computer Rendering for
Mochly-Eldar Architects, where he lends his extensive experience with the creation and detection of
virtual imaging. Contact him at firstname.lastname@example.org.
Gregg Helvey, DDS, MAGD
Dr. Gregg Helvey graduated from Georgetown University School of Dentistry in 1976. He is part of an
elite group of dentists who are also skilled ceramists. This combination of experience as a dentist and
laboratory technician has aided him in the development of unique restorative and laboratory procedures,
many of which have been published in peer-reviewed journals. Dr. Helvey serves on the editorial
board of Inside Dentistry, Compendium of Continuing Education in Dentistry and Inside Dental
Technology. An AGD Master since 1997, he is an adjunct associate professor at Virginia Commonwealth
University School of Dentistry and teaches in the AEGD residency program emphasizing all-ceramic restorations.
Dr. Helvey continues to lecture nationally and internationally and maintains a private practice
in Middleburg, Va. Contact him at 540-687-5855, www.gregghelveydds.com or email@example.com.
David S. Hornbrook, DDS, FAACD
Dr. David Hornbrook graduated from UCLA School of Dentistry and currently practices in San Diego,
Calif. A leading educator in esthetic dentistry, he has been a guest faculty member of the postgraduate
programs in cosmetic dentistry at Baylor, Tufts, SUNY at Buffalo, UMKC and the UCLA Center of Cosmetic
Dentistry. Dr. Hornbrook has also consulted with numerous manufacturers in product development
and refinement and is on the editorial board of many dental journals. He is a past editor of the Journal
of the American Academy of Cosmetic Dentistry and an accredited member and Fellow of the AACD.
Founder and past director of P.A.C.~live and the Hornbrook Group, Dr. Hornbrook continues to lecture
internationally. Contact him at www.davidhornbrook.com.
Daniel J. Melker, DDS
Dr. Daniel Melker graduated from Boston University School of Graduate Dentistry in 1975 with specialty
training in periodontics. Since then, he has maintained a private practice in periodontics in
Clearwater, Fla. Dr. Melker lectures at the University of Florida periodontic and prosthodontic graduate
programs on the periodontic-restorative relationship. He also presents at UAB, University of Houston,
Baylor University and LSU’s graduate periodontal program. Dr. Melker has published several articles
in national dental magazines, as well as The International Journal of Periodontics & Restorative Dentistry,
and has twice been honored with the Florida Academy of Cosmetic Dentistry Gold Medal. Contact
him at 727-725-0100.
Ellis J. Neiburger, DDS
Dr. Ellis “Skip” Neiburger graduated from University of Illinois at Chicago College of Dentistry in 1968.
He practices general dentistry in Waukegan, Ill. A former vice president of the American Association of
Forensic Dentists, Dr. Neiburger has been the association’s journal editor since 1978. His other experience
includes publisher/editor for Dental Computer Newsletter (the journal that introduced computing
to the dental field) and consultant for Apple Computer Inc. In addition to a background in computer
technology and dentistry, Dr. Neiburger also has practical knowledge of law enforcement and was Lake
County, Ill., deputy coroner for many years. Contact him at 847-244-0292 or firstname.lastname@example.org.
is the object most often choked on by
Americans. Since 1900, 17,000 people
have died from choking on toothpicks,
including novelist Sherwood Anderson.
prescribed in 1997.
prescribed in 2010.
1 out of 3
of the last
A2 and A3.
The amount of
teeth last before
by the next row.
1 out of 2
dentists in Massachusetts sent
a case to Glidewell in 2010.
BruxZir crown & bridge
units were ordered the week
of Dec. 13, 2010, making it
the fastest-growing product
in lab history.
1 out of 142
of the last
distance to keep
your toothbrush from
your toilet to avoid
from the flush.
PRODUCT........ aveoTSD ® Health Professional
Patient Sizing Kit
SOURCE........... Glidewell Laboratories
Newport Beach, Calif.
One of the most common questions I field from
dentists is: “Does that aveoTSD thing actually work?”
Yes, it does, but I understand why they ask. It is a
simple appliance (especially compared to other antisnoring
appliances) with no moving parts that looks
too good to be true. It anteriorizes the tongue directly
without involving the teeth or jaws, hence there is no
need for straps or hinges.
The aveoTSD Health Professional Patient Sizing
Kit is now available to dentists for helping patients
achieve a perfect fit of the device. The extra-oral
titration rings come in 4 mm and 7 mm thicknesses
to accommodate patients with
longer-than-average tongues. And although
the medium size aveoTSD fits
90 percent of patients, the sizing
kit also contains a small and a
large aveoTSD for patient
sizing. Additionally, the
components can be
placed back into the
blue kit for sterilization
Dr. DiTolla’s Clinical Tips 9
PRODUCT........ OptiBond XTR
SOURCE........... Kerr Corporation
Since the introduction of BruxZir ® Solid Zirconia,
I have been looking for a way to bond these monolithic
restorations into place whether using totaletch,
self-etch or conventional cementation. Zirconia
is notoriously tough to bond to, but OptiBond XTR
provides a solution. It also has helped me reduce
post-op sensitivity. And due to its film thickness of
5 to 10 microns, I am able to light cure OptiBond
XTR prior to placing restorations without worrying
about them seating all the way. I simply apply the
OptiBond XTR Primer to the inside of the BruxZir
restoration, air thin and light cure. To bond to the
tooth, I apply the primer with a scrubbing motion
and then air thin. Then I apply the OptiBond XTR
Adhesive to the tooth, air thin and cure. Finally, I fill
the BruxZir restoration with the cement of my choice,
seat it on the tooth, and I’ve got a virtually unbreakable
crown or bridge with a high-strength bond.
PRODUCT........ Clear-Lock Retainers for Life
SOURCE........... Glidewell Laboratories
Newport Beach, Calif.
I often get asked to make retainers for patients who
don’t want to bother going back to their orthodontic
office five years after their first appliance was made.
Most of the time the patient’s teeth have slightly relapsed,
and while he or she doesn’t care enough to
have more ortho, the patient doesn’t want his or her
teeth to get any worse. Thanks to Invisalign ® , patients
now prefer clear retainers to the old pink acrylic
and wire Hawley retainers many of us grew up with.
Glidewell started making clear retainers for dentists
a few years ago. With the advent of CAD/CAM, the
lab realized we could make multiple sets of retainers.
This is especially practical when the patient loses or
damages his or her retainer, which always happens.
The lab now offers Clear-Lock Retainers for Life, a
service in which we send you either three single-arch
retainers (three uppers or three lowers) or one set of
three upper and three lower retainers to give to the
patient. When all the retainers are lost or damaged,
contact us and we will send you three more from our
digitally stored data. It’s a great service that even your
orthodontist doesn’t provide!
Dr. DiTolla’s Clinical Tips11
PRODUCT........ IOS FastScan ®
SOURCE........... IOS Technologies Inc.
San Diego, Calif.
I will readily admit that digital impressions are the
future of dentistry. But as of today, the ROI of digital
systems leaves a lot to be desired. Enter IOS FastScan.
Glidewell Laboratories has been the main clinical testing
facility for IOS Technologies’ IOS FastScan, and I
have spent a lot of time with it in my hands over the
last three years. Besides the fact that it might be the
fastest scanner for digital impressions, I think ROI
will be the feature dentists love most. For any monolithic
IPS e.max ® or BruxZir ® IOS FastScan digital file
you send to the lab, you will save $27 — that’s comprised
of $7 savings on inbound shipping, $10 savings
on impression material, and $10 off the restoration
list price because it can be digitally fabricated without
making a model. No other scanning system gives you
the ability to save this much on every crown you scan.
In fact, many digital systems actually cost you more.
Are You Using
– ARTICLE by
Gordon J. Christensen, DDS, MSD, Ph.D
Most people find it difficult to pass up a bargain, and
dentists and dental staff members who select and order
products are no exceptions. It is relatively common to see
dental products offered in dental magazines and journals
at discounts of 10 percent to 50 percent.
Are you using products purchased at significant discounts?
As staff members typically handle the ordering of supplies
in most dental offices, do you, the dentist, even know if you
are using such products?
A key question to ask is: How can some dental retailers sell
dental supplies at deeply discounted prices, while others
continue to sell at the recognized market level? Deeply discounted
products may not be legitimate ones produced by the
manufacturer from which you think you are buying. You may
be using “gray-market” or even counterfeit products without
Gray-market products include branded goods intended by the
brand owner for one national market that are diverted and
resold by unauthorized distributors to another market. Counterfeit
products, on the other hand, never originate from the brand
owner. Counterfeiters simply pass off fake materials under the
guise of a well-known product. There is a surprising lack of published
information on this subject. However, a few related articles are
A key question to ask is: How can
some dental retailers sell dental
supplies at deeply discounted
prices, while others continue to
sell at the recognized market
level? Deeply discounted
products may not be legitimate
ones produced by the
manufacturer from which you
think you are buying. You
may be using “gray-market”
or even counterfeit products
without knowing it.
Large dental companies, such as 3M ESPE (St. Paul, Minn.), DENTSPLY (York, Pa.) and Kerr (Orange, Calif.), deal
with gray-market and counterfeit products regularly, and some find it difficult to estimate what percentage they
represent of products sold. Kirsten Edwards, director of clinical affairs for Kerr, estimated that approximately
5 percent to 8 percent of apparent Kerr products are gray-market or counterfeit (oral communication, Feb. 23,
2010). These products are sold under the pretense of being brand-name items.
Purchasing discounted dental products saves money, but is it worth the potential hazards of buying and using
such products? For example: Say you gross $600,000 per year with a 60 percent overhead before taxes, and your
supply expenses are equivalent to about 5 percent of your gross income, or about $30,000 for the year. Assuming
you save 10 percent off your supply cost, you’ll save $3,000 in a year, or $250 per month. However, what if
these discounted products are expired, altered or even counterfeit, and you have a material failure — such as
postoperative tooth sensitivity — in a group of patients? Additionally, the legal liability associated with using
a dental material that is not approved for sale in the U.S. or cannot be tracked back to its origin of sale is a
significant threat. Even if you determine the cause of the problem, have you really saved anything? Is it worth
the $250 per month savings? To whom do you go when the product does not meet its expressed purpose or
you have problems with patient complaints?
In this article, I discuss the prevalence of gray-market and counterfeit products and manufacturers’ concerns
about them; the need for communication between the dentist and the staff member(s) ordering the dental
products; how to identify gray-market and counterfeit products; and, most importantly, what to do to avoid
Are You Using “Gray-Market” or Counterfeit Dental Products?15
There are other reasons I
prefer to purchase from these
major distributors. By doing
so, I know that in spite of
often paying somewhat more
for some items, I have their
repair support. Additionally,
I can ask their local sales
representatives about the
properties of specific products
and the acceptance or
rejection that products are
receiving in my community.
DENTAL INDUSTRY’S CONCERNS
REGARDING GRAY-MARKET AND
The U.S. Food and Drug Administration (FDA) regulates
the dental industry, ensuring that dental medical devices —
or the dental products used and placed in patients’ mouths
— meet accepted standards. The FDA also approves manufacturers’
claims and inspects manufacturing facilities for
Manufacturers’ concerns about gray-market and counterfeit
products are about more than financial loss. They also center
on potential health risks for patients and negative brand
perception among clinicians who might use a gray-market or
counterfeit product and not get the expected clinical result.
3M ESPE Global Director of Channel Sales Kathy Gaertner
stated that the company sees the presence of unauthorized
intermediaries selling products that are not authorized for
sale in the U.S. (written communication, Feb. 23, 2010). These
items often are products intended for sale in developing countries
that have been repackaged and sent back to the U.S. for
sale to American dentists. When products not cleared for sale
in the U.S. are repackaged, you cannot be guaranteed that you
are buying the product you think you are buying. Warning and
traceability information may be missing, and the products may
no longer comply with regulatory requirements. Oftentimes, these
repackaged products are outdated or expired with a fraudulent
extended expiration date. The gray-market product may have been mishandled,
resulting in compromised product efficacy.
“The only way to know you’re getting the 3M ESPE product quality you trust is to purchase [products] through
certified 3M ESPE distributors,” stated Gaertner.
DENTSPLY Chief Clinical Officer Dr. Linda Niessen described the company’s concerns about gray-market and
counterfeit products not providing the clinical outcomes that dentists have come to expect from DENTSPLY
brands (written communication, Feb. 23, 2010). Company personnel routinely see examples of discounted
noncompliant, expired or repackaged DENTSPLY products. They have seen cases in which early generations of
products, no longer registered with the FDA, are acquired in developing markets. These products are imported
illegally into the U.S. and resold to U.S. dentists as the newest product under different brand names. The primary
packages are labeled clearly as the early-generation product, while the directions for use and the invoice
falsely claim the product to be the newest-generation product. Gray-market activity not only creates a clinical
risk exposure for dentists, but also deprives their dealer partners of the opportunity to supply a quality product
behind which the manufacturer will stand. DENTSPLY has 22 authorized dealer partners; Dr. Niessen said
that if a DENTSPLY product comes from anyone else, it is likely to be counterfeit or altered.
Kirsten Edwards of Kerr stated that counterfeit OptiBond ® Solo Plus , Herculite ® and other popular Kerr
brands have been sold through unauthorized dealers (oral communication, Feb. 23, 2010). To the naked eye,
the packaging appears to be identical to the official company packaging. This includes lot codes that match
legitimate codes for lots sold to authorized dealers. The company cautions dentists that if the price of a Kerr product
is significantly below standard U.S. or Canadian pricing, the product is likely to be gray-market or counterfeit and
could violate civil and criminal laws. Kerr also has filed a citizen petition with the FDA seeking action against several
unauthorized dealers that have been found distributing gray-market or counterfeit Kerr products. As of the publication
of this article, no action has been taken by the FDA to stop this activity.
It is obvious that unscrupulous, profit-motivated distributors can find many ways to simulate popular products and
sell them to dentists at discounted prices. The Internet has made this easier.
HOW DO GRAY-MARKET OR COUNTERFEIT
PRODUCTS GET INTO YOUR OFFICE?
How can we identify gray-market and counterfeit products before they arrive at our office? In order to reduce or
eliminate this problem, dentists must change their behaviors.
Who in your office orders and purchases dental supplies? If you are a typical dentist, dental supplies are ordered,
purchased, shelved and placed in the operatory by a competent, knowledgeable dental assistant or, in some offices,
by the office manager. These loyal staff members are eager to please you by making inexpensive supply purchases.
Bargain rates of 10 percent or more off standard prices are as attractive to them as they are to you.
How many relatively unknown companies vie for your supply business? Advertisements come through your office
on a daily basis, and staff members collect these ads to make choices about the company from which to order.
Do you routinely meet with the staff member in charge of ordering to review and confirm the brands and prices
of the products? Does this staff member know the necessity of confirming that the distributor is an authorized
dealer? It is doubtful that in an organized office, in which the dentist has delegated responsibility to staff members,
that the dentist and the staff member who orders supplies meet to discuss product ordering. In my opinion,
such a meeting would reduce or eliminate the problem of gray-market and counterfeit product proliferation.
It is time for every dentist to hold these meetings.
I suggest that on a scheduled basis, the dentist and the staff member ordering supplies meet to determine
desired brands and needed quantities of these brands of products. Before the meeting, the staff member can
collect information about the various companies from which specific categories of products are available and
have the information ready for the dentist’s review at the meeting. This preparation will reduce the time needed
for the meeting, which can be brief.
Manufacturers sell their products either directly to you or through their authorized distributors and dealer
partners. Ordering only from known, authorized retailers will ensure that the products are legitimate and from
All major manufacturers have lists of authorized distributors available. If you have a question about the legitimacy
of a discounting distributor, you can verify that the distributor is an authorized retailer by contacting the
Purchasing from the major U.S. distributors such as Benco Dental, Burkhart Dental Supply, Darby Dental
Supply, Goetze Dental, Henry Schein and Patterson Dental helps ensure that the supplies are legitimate, and
covered by warranties and manufacturer support. There are other reasons I prefer to purchase from these
major distributors. By doing so, I know that in spite of often paying somewhat more for some items, I have
their repair support. Additionally, I can ask their local sales representatives about the properties of specific
products and the acceptance or rejection that products are receiving in my community.
Are You Using “Gray-Market” or Counterfeit Dental Products?17
HOW DO YOU IDENTIFY GRAY-MARKET
OR COUNTERFEIT PRODUCTS?
There are several ways to identify potentially gray-market or counterfeit dental supplies.
Low price. The product is selling for significantly below the known market price. You may determine the market
price by looking in the online or printed catalogs of the major dental retailers noted earlier.
Unknown distributor name. You know the major retailers, and you know the major private-label independent
companies that do not sell via the major retailers. If the company selling the product does not have a recognizable
name, you have reason to be suspicious. Do some homework to learn about the supplier, particularly if you are
purchasing online, before you make a purchase decision.
Suspicious packaging. If you attend a dental meeting and see a significantly discounted apparently identifiable
product, you should consider the following relatively easily observable characteristics. Examine the printing on
the package. Is it smeared, irregular, uneven or not of the quality you have previously observed on packaging
of products with the same brand name? Is the product name current or a previous name you remember from an
earlier version of the product? Is the bar code or any aspect of the product description blocked out? Is the product
marked “For export only” or “Not registered for sale in the European Union or United States”? Be sure the label on
the product matches the product name on the directions for use. Is the language on the package something other
Check the expiration date. Is the product expired? Does it appear that the expiration date has been changed?
If you become suspicious of a product while attending a convention, go to a known authorized distributor of the
brand in question, examine its packaging and ascertain the price of the product. You may see an immediately
ACTIONS TO TAKE RELATIVE TO
GRAY-MARKET AND COUNTERFEIT SUPPLIES
I suggest the following preventive actions to avoid the problems potentially related to purchasing gray-market
or counterfeit products.
Use authorized distributors. If you have any question about the legitimacy of a distributor, call the manufacturer
and request a verification of the distributor’s authenticity.
Expect to pay a fair market price for products. Authorized distributors offer occasional price reductions as
specials. However, brand-name products have an expected fair price that does not vary significantly among
Avoid deeply discounted prices. If the price is too good to be true, you probably are looking at a suspect
Investigate. If you have questions about any product, have your staff investigate the retailing company by
visiting the manufacturer company’s website and comparing the image and description of the product in
question with the manufacturer’s information. Most manufacturing companies feature images of their products
on their websites.
In addition, dental manufacturers themselves are taking steps to prevent gray-market or counterfeit products.
They are using new types of labeling to facilitate the identification of gray-market and counterfeit products. When these
products are identified, the manufacturers are taking action against the vendors to remove them from the market.
As verified by dental manufacturers, there is no question that gray-market and counterfeit products are being
distributed and sold on the U.S. dental market. “Buyer-beware” policies should prevail in dental offices. Dentists
should meet with and assist office staff members in selecting products and identifying authorized product distributors.
Questionable products and unknown, unauthorized distributors should be avoided. Although discounted dental
products are available, the cost of overcoming the potential problems for patients caused by inferior products can
be far greater than the amount saved. CM
Dr. Gordon Christensen is the director of Practical Clinical Courses and cofounder of the nonprofit Gordon J. Christensen CLINICIANS REPORT ® . Contact him at
801-226-6569 or email@example.com.
1. Santerre P, Conn A, Teitelbaum B. Toronto Academy of Dentistry winter clinic panel discussion on gray-market and counterfeit dental materials.
J Can Dent Assoc. 2008;74(3):233–35.
2. Lewis K. China’s counterfeit medicine trade booming. Can Med Assoc J. 2009;181(10):E237–38.
3. Gautam CS, Utreja A, Singal GL. Spurious and counterfeit drugs: a growing industry in the developing world. Postgrad Med J. 2009;85(1003):251–56.
4. Schweim JK, Schweim HG. Internet pharmacies and counterfeit drugs (in German). Med Klin (Munich). 2009;15;104(2):163–69.
Christensen GJ. Are you using “gray-market” or counterfeit dental products? JADA. 2010;141(6):712–15. Copyright ©2010 American Dental Association.
All rights reserved. Reprinted by permission.
Are You Using “Gray-Market” or Counterfeit Dental Products?19
– ARTICLE and CLINICAL PHOTOS by
Gregg Helvey, DDS, MAGD
The all-ceramic crown was developed in the early 20th century when Charles H. Land patented the allporcelain
“jacket” crown to improve esthetics. This procedure consisted of rebuilding the missing tooth
with a porcelain covering, or “jacket” as Land called it. To solve the product’s strength problems, Abraham
Weinstein in the late 1950s introduced a metal core to which porcelain was fused, thus creating the
ceramo-metal crown. Throughout the years, the metal has been substituted with different materials to
achieve a more esthetic result. Problems have been reported with the fusion between the ceramic and the
core, which have resulted in debonding of the veneered ceramic. Further investigations in dental material
science have produced tremendous advances in unveiling aspects that have been taken for granted, such
as the bond strength between different materials that comprise the crown restoration. Recently, a lithium
disilicate material that was once used solely as a core material was introduced as an all-ceramic alternative.
This article discusses the strength factors that comprise a monolithic and bilayered ceramic restoration.
Monolithic Versus Bilayered Restorations21
Advances in the field
of dental ceramics
can take time to find
acceptance in the dental
community. Ceramic materials
are usually employed in
higher-end procedures, and
the clinician is compelled to
deliver a product that has a
proven durable and esthetic
track record. Materials and
procedures must have the
science behind them and
the endorsement of leading
clinicians before being introduced.
Only then can these
materials become part of
the dentist’s restorative armamentarium.
For years, the ceramo-metal
restoration has been the
gold standard in crown &
bridge procedures. Although
durable and time-tested, this
type of restoration may not
be the most esthetic. For
years, patients have asked
for metal-free restorations,
and the industry has accommodated
this request with
various resin composite and
These newer systems have an effect on the actual fabrication
methods. Traditionally, the ceramo-metal restoration
is constructed by casting a metal coping and applying
a porcelain opaque layer followed by layering veneering
porcelain. Newer methods have bypassed the coping
fabrication step. Using a vacuum-pressing system, allceramic
restorations are waxed to full contour and
invested, wax burnt out and hot-pressed, creating a solid
ceramic restoration. The question remains if these allceramic
monolithic forms can endure the rigors of an
intraoral restoration as well as the bilayered porcelain-tometal
All-Ceramic Crowns: Bilayered Versus Monolithic
Numerous bilayered crown systems that are supported
by a substructure core are available. Various materials are
used to create these substructures, e.g., metal alloys, alumina
and zirconia. Often, ceramo-metal crowns have been
used because of their strength, biocompatibility and esthetics.
1 Patient demand for more esthetic restorations has
Figure 1: For several decades, the ceramo-metal crown
has been the “workhorse” restoration.
Figure 2: Anterior ceramo-metal crowns display the less
esthetic opacity that is sometimes evident in metal-substructure
gradually increased, leading
to greater use of nonmetallic,
high-strength core materials.
These esthetic core materials
include alumina, zirconia,
magnesium aluminate spinel
and lithium disilicate. Once
the cores are fabricated, the
laboratory technician applies
veneering porcelain to create
the final esthetic restoration.
2,3 Yet all of these porcelain-laminated
a common mode of failure:
fracture of the veneering
ceramic from its core.
There are three basic configurations
crowns: bilayered ceramometal,
lithium disilicate. While numerous
studies are cited
in the literature, specific
comparative tests uniformly
conducted on all three
systems are difficult to find.
The testing methods, sample
sizes and the instrumentation
used in the studies are
variables that must be considered.
Therefore, strength comparisons of different
studies can be misleading. However, after reviewing the
body of literature, a different perspective may be gained
as to the overall strength of each system, rather than one
Through the years, replacement and reinforcement
of the human tooth has evolved from a monolithic design
(gold crown) to a bilayered design (ceramo-metal
and ceramo-zirconia) and again to a monolithic design
(lithium disilicate/full zirconia). In the past several
decades, the workhorse restoration is the ceramo-metal
crown: a metal substructure in which ceramic material
is layered or pressed to form the anatomic shape of
the restoration (Figs. 1, 2). The weakest point is the
ceramo-metal interface. The exact mechanism of porcelain-to-metal
fusion is unknown; however, at least four
theories have been discussed.
1. The theory of van der
Waals forces 4 refers to the
bonding of materials created
by the attraction of charged
atoms that do not exchange
electrons. These secondary
forces are generated more
by a physical attraction between
charged particles than
by an actual sharing or exchange
of electrons in primary
(chemical) bonding. 5
2. The theory of mechanical
retention of ceramic to
a metal coping is derived
from the microscopic irregularities.
The contribution of
may be relatively limited because
ceramic does not require
a roughened area to
bond. 5 Lacy 4 has shown that
ceramic will fuse to a wellpolished
metal surface; however,
some surface roughness
does contribute to an
increased bond. 6–8 Therefore,
mechanical retention alone
is probably not sufficient to
entirely explain how dental
ceramic adheres to a metal
3. Bonding of porcelain to metal by means of compression
is the third theory. Dental porcelain, like most brittle
materials, is strong in compression but relatively weak
when subjected to tensile stresses. Its tensile strength
is approximately 4 percent of its compressive strength. 9
Compressive stress in the layering porcelain reinforces
the fracture strength. A thermal mismatch between
the coping and the porcelain leads to compressive or
tensile stress depending on whether the coefficient
of thermal expansion of the porcelain is higher or
lower than that of the coping. 10 The expansion of the
porcelain must be lower than that of the coping to
generate compressive stress during cooling. 11 The
development of compressive forces in the porcelain and
tensile forces in the metal is due to the difference in contraction
4. Chemical bonding is the final generally accepted theory
as the primary mechanism of ceramic-to-metal attachment.
12–14 The mode of bonding involves the metal surface
Figure 3: Ceramo-metal failures are multifactorial and
can be related to a combination of reasons.
The literature cites studies
observing various ceramometal
rates range between
5 percent and 10 percent
over 10 years.
oxides dissolved by the applied
ceramic opaque layer.
This results in an atomic contact,
whereby shared electrons
form ionic and covalent
bonds between the oxide layer
on the metal surface and
the ceramic opaque layer. 12,13
The literature cites studies
observing various ceramometal
failures. Failure rates
range between 5 percent and
10 percent over 10 years. 15
Strub et al. found failure
rates of ceramo-metal restorations
as high as 3 percent
over five years. 16 Hankinson
and Cappetta 17 and Kelsey
et al. 18 found a failure rate
between 2 percent and
4 percent that occurred after
two years. They also
found that, due to a repetition
of consistent occlusal
contacts, after four to five
years the failure rate rose to
20 percent to 25 percent.
A ceramo-metal failure is a
multifactorial problem related
to a combination of reasons 1 (Fig. 3). Some studies
attribute failures to environmental factors, particularly
moisture. A moist environment was found to reduce the
ceramo-metal strength by 20 percent to 30 percent. 19 In
the presence of moisture, the silicon-oxygen bond between
metal and ceramic weakens and promotes failure
because of water propagation at the crack tip. 20 Most
frequently, ceramic failures are related to the cracks in
the ceramic. 1 Small scratches on the ceramic surface can
act as notches where the concentration of stress can exceed
the theoretical strength of the ceramic. As the crack
propagates through the material, the stress concentration
is maintained at the crack tip until the crack moves
completely through the material. 21
Technical errors in the laboratory can also account for
ceramo-metal failures. A void or pore that remains after
the fabrication can be the site of weakness and eventual
failure. 22 Porosity does occur between ceramic particles
during the ceramic application, and the technician should
make every effort to minimize this.
Monolithic Versus Bilayered Restorations23
Diaz-Anold et al. found several
reasons for failure, including
faulty metal structure
design and incompatible coefficients
of thermal expansion
between the metal and
the ceramic material. 23
Another reason was insufficient
metal support for the
ceramic, leading to unsupported
of ceramic, technical flaws
in the porcelain application,
and occlusal forces or trauma.
Ceramic material properties,
crack length, fracture
toughness and applied stress
intensity, also contribute to
Usually, a catastrophic failure
is the result of crack
initiation and propagation.
Llobell et al. described reasons
for intraoral ceramic
failure: impact load, fatigue
load, improper design and
microdefects within the material.
They also found that
masticatory repetitive forces,
occlusion, created alternating
forces, contributing to
the fatigue of ceramo-metal
restorations. 24 Typically, one
factor alone does not cause
rather, the cumulative effect
of a large number of comparatively
leads to failure. 1
Bond Strength of
Porcelain to Metal
The ideal test to determine the bond strength between
ceramics and metal does not exist, although several
methods have been used. 25 Several tests have been employed
to evaluate the ceramo-metal bond strength 26 :
shear test (maximum stress that a material can withstand
before failure in shear), 27 planar shear test (opposing forces
are applied parallel to the cross-sectional area under
test), 25 tensile, 28 flexural 29 and torsional strength. 30 Chong
Figure 4: Before the zirconia substructure is placed on
a solid working model, the separating medium has been
applied prior to wax application.
Sufficient bond strength
ceramic and zirconia
is a concern for longterm
of the veneering ceramic
constitutes clinical failure
and has been reported
to occur at a rate of 13
percent during a threeyear
and Beech 27 proposed the
circular-planar surface shear
test, which provided standardization
and ease in specimen
Scolaro et al. 26 tested different
ceramics that were
bonded to a palladium-silver
alloy (Pors-On 4; DENTSP-
LY Ceramco; Burlington,
N.J.). They used Ceramco
(DENTSPLY), Noritake Super
Porcelain EX-3 (Cincinnati,
Ohio) and VITA VMK ®
68 (Vident; Brea, Calif.).
The shear bond strength
results were: Noritake
(28.96 MPa ± 6.92 MPa),
Ceramco (28.20 MPa ±
8.65 MPa) and VITA VMK 68
(24.11 MPa ± 6.27 MPa).
Akova et al. 32 compared the
bond strength of layering
porcelain to cast Ni-Cr and
Co-Cr alloys to laser-sintered
Co-Cr alloy. In this study, the
mean shear bond strength
was the highest for the base
metal Ni-Cr (81.6 MPa ±
14.6 MPa) and slightly less for
the Co-Cr base metal
(72.9 MPa ± 14.3 MPa). The
shear bond strength of the
laser-sintered Co-Cr metal
was 67 MPa ± 14.9 MPa.
Joias et al. 31 tested the shear
bond strength of a ceramic
to five commercially available
Co-Cr alloys. The same
ceramic (VITA Omega 900,
Vident) was bonded to
each alloy. The shear bond
strength test was performed
in a universal testing machine with a crosshead speed of
0.5 mm/min. The ultimate shear bond strength ranged
from 61 MPa to 96 MPa.
According to Powers and Sagaguchi, 26 an adequate bond
occurs when the fracture strength or fracture stress
(the stress at which a brittle material fractures) is above
25 MPa. Other studies also have accepted a sufficient bond
for metal-ceramics when the fracture stress is greater
than 25 MPa. 1,33–35 Because
this value represents the
limit of the test, it could be
argued whether this were a
true representation of adequacy.
36 As previously noted,
some ceramo-metal systems
in other studies have tested
A recently introduced laboratory
method of ceramic application
to metal is the use
of the lost-wax technique, in
which a pressable ceramic is
applied to an opaque metal
or zirconia core (Figs. 4–7).
This is a simpler and quicker
method than the conventional
technique and eliminates
the need for the 20 percent
shrinkage compensation with
traditional porcelain firing. 37
Venkatachalam et al. 38 compared
initiation strength of a leucite-based
The metal specimens
alloy and chrome-cobalt
base metal alloy divided into
two groups of 20 samples.
The mechanical testing method
used in this study was the
three point bending test standardized
by the International Organization for Standardization
(ISO), 39 which is now considered the gold standard
for examining metal-ceramic bond strength. 38 Their
findings showed a mean debond strength for feldspathic
porcelain to the base metal alloy of 36.11 MPa ± 2.31 MPa,
while the feldspathic porcelain to the gold-palladium
alloy demonstrated a mean bond strength of 42.64 MPa
± 1.94 MPa. For the ceramic-pressed-to-metal specimens,
the mean debond strength of the base metal combination
was 37.47 MPa ± 6.02 MPa and 47.94 MPa ± 3.92 MPa for
the gold-palladium samples.
The actual mechanism of bonding ceramic to zirconia
substructures is not completely understood, nor is the
Figure 5: After wax is injected onto the zirconia substructure,
the margins are refined on the removable die.
Figure 6: The undersurface of a single zirconia-based
crown after the waxing phase is completed
manipulation of surface
treatment of zirconia in the
quality of the bond. 40–42 Sufficient
bond strength between
veneering ceramic and zirconia
is a concern for long-term
success. 10 Chipping of the
veneering ceramic constitutes
clinical failure and has
been reported to occur at
a rate of 13 percent during
a three-year observation. 43
In a follow-up study, Sailer
et al. found the failure rate
increased to 15.2 percent
during a five-year period. 44
One approach to enhancing
strength is sandblasting,
which increases the surface
roughness and provides
undercuts. 38–40 Conversely,
Kosmac et al. 45 and Guazzato
et al. 46 found sandblasting
adversely affects the mechanical
strength of the zirconia
by initiating a phase transition
(tetragonal to monoclinic
form) and probably has
a detrimental effect on the
bonding capacity. This phase
transition of tetragonal zirconia
to monoclinic zirconia
results in a significantly
lower coefficient of thermal
Fischer et al. 47 investigated the effect of different surface
treatments on the bond strength of veneering ceramics
to zirconia. Their study assessed the influence of treating
the zirconia surface by polishing, sandblasting, silica
coating and applying a liner. They also studied the impact
of regeneration firing, which entails firing the zirconia
framework for 15 minutes at 1,000 degrees Celsius
prior to veneering. This re-establishes the tetragonal lattice
after sandblasting or grinding to obtain better bond
strength. 48 Five different layering ceramics were used.
The shear strength of all the types of surface conditions
was 23.5 MPa ± 3.4 MPa to 31 MPa ± 7.1 MPa. In all specimens,
the fracture started at the core-veneer interface
and continued into the veneering ceramic, which
remained on the core. The weakest link was not the
Monolithic Versus Bilayered Restorations25
interface, but the veneering
ceramic itself. This study
concluded that increased
surface roughness did not
enhance shear strength, the
application of a liner did not
improve shear strength, and
regeneration firing decreased
the shear strength. The recommendation
to realize the
benefit of high-strength zirconia
as a framework was
to strengthen the veneering
Although the zirconia substructure
a high percentage of failures
of the ceramo-zirconia restoration
are found in ceramic
chipping and delamination.
A randomized, controlled
clinical trial showed the performance
of 3-unit posterior
prostheses using three ceramo-metal
and five major companies’
zirconia technologies. 52
The researchers evaluated
the framework and the veneering
ceramics. The report
showed veneering ceramic
fractures were five times
more prevalent with ceramic
formulations used on zirconia
versus those employed
In another study, Taskonak
et al. 53 determined the site
of crack initiation and the
causes of fracture in failed
zirconia-based ceramic fixed
partial dentures. Fractures
that had origins on the ceramic
veneer surface had
failure stresses between 31
MPa and 38 MPa.
Figure 7: Facial view of the finished restoration
Aboushelib et al. 54 stated that the bond strength between
veneer ceramic and the zirconia framework is the weakest
component in the layered structure. To enhance the final
esthetics of layered zirconia-based restorations, colored
The lithium disilicate
crystals … This crystal
size and orientation
causes cracks to deflect,
branch or blunt, which can
account for the increase
in flexural strength and
compared to leucitereinforced
pigments are incorporated
into the surface of the zirconia
framework (Fig. 8).
The objective of this study
was to investigate the effect
of zirconia type (white or
colored) and its surface finish
on the bond strength to
two veneer ceramics. They
found the addition of coloring
pigments resulted in a
significantly weaker bond
strength compared to the
white zirconia frameworks.
In a comparative study,
Guess et al. 55 evaluated the
shear bond strength between
various commercial zirconia
core and veneering ceramics
and the effect of thermocycling.
Using the Schmitz–
Schulmeyer test method,
they evaluated the coreveneer
shear bond strength
of Cercon ® base to Cercon
Ceram S; VITA In-Ceram ®
YZ cubes to VITA VM9; and
DC-Zirkon to IPS e.max ®
Ceram (Ivoclar Vivadent;
Amherst, N.Y.). As a control
specimen, they used
a ceramo-metal system,
DeguDent U94 (DeguDent,
a DENSTPLY Company)
to VITA VM13. Half of
each specimen group was
thermocycled at 5 degrees
Celsius to 55 degrees Celsius
for 20,000 cycles. Their
results demonstrated the
shear bond strength values
of 12.5 MPa ± 3.2 MPa for
VITA In-Ceram YZ Cubes/
VITA VM9, 11.5 MPa ±
3.4 MPa for DC-Zirkon/
IPS e.max Ceram and 9.4 MPa ± 3.2 MPa for Cercon
base/Cercon Ceram S. The specimens that were thermocycled
did not show any significant differences.
The control ceramo-metal specimen showed a higher
shear bond strength, regardless of thermocycling, of
27.6 MPa ± 12.1 MPa.
The first all-ceramic restorative
system was introduced
in 1903 by Charles Land. 56
The so-called porcelain
“jacket” crown was fabricated
with high-fusing feldspathic
porcelain. Although it was
noted for natural esthetics,
the failure rate was high,
probably due to the low
strength of the porcelain.
57 Interest in all-ceramic
restorations has grown
throughout the years.
Developments have included
several bilayered systems consisting of a ceramic-type substructure
interfaced with a veneering ceramic.
Recently, a monolithic approach was introduced using
lithium disilicate glass ceramic (e.g., IPS e.max Press and
IPS e.max CAD). This material has two forms: a homogeneous
ingot with various degrees of opacity used with
hot-pressed technology and a pre-crystallized block used
with CAD/CAM technology. Both forms can be used in a
full anatomical contour method with the application of
stain and glaze or a cutback and layering technique.
The CAD milling blocks are produced for distribution
using a glass technology. This process prevents the
formation of defects and voids throughout the block and
allows for an even distribution of the pigmentation. This
partial crystallization process forms lithium-metasilicate
crystals, which provide sufficient strength for milling.
According to the manufacturer, the partially crystallized
milling block has a microstructure consisting of 40 percent
lithium-metasilicate crystals, which are embedded
in a glassy matrix. The grain size of these crystals
ranges from 0.2 μm to 1 μm. At this point, the lithium
metasilicate block has a flexural strength of 130 MPa,
which is comparable to leucite-reinforced CAD/CAM
blocks (ProCAD, Ivoclar Vivadent) and feldspathic
CAD/CAM blocks (Vitablocs ® Mark II, Vident). 58 After
milling, the pre-crystallized restoration is placed in the
mouth and adjusted, if necessary. The restoration is then
crystallized during a 20-minute firing cycle using a twostep
ceramic furnace. Because the restoration can be
milled to full contour, there is no ceramic infiltration
process or veneering process. The restoration shrinks
0.2 percent during crystallization, which the computer
software accounts for during the milling process. During
the crystallization cycle, the lithium-metasilicate restoration
reaches a temperature of 840 degrees Celsius to
Figure 8: A shade base stain is applied to the zirconia
framework and fired prior to application of the veneering
850 degrees Celsius. During
the temperature rise, a
controlled growth of lithium
disilicate crystals occurs,
producing a transformation
of the microstructure that
results in an increase of the
final flexural strength of 360
MPa. This flexural strength is
approximately three to four
times stronger than leucitereinforced
glass ceramics. 59
This glass ceramic is comprised
of 70 percent prismatic
lithium disilicate crystals (0.5
μm to 5 μm long) dispersed
in a glassy matrix. 26 The lithium
disilicate microstructure has numerous small interlocking
plate-like crystals randomly oriented. This crystal
size and orientation causes cracks to deflect, branch
or blunt, which can account for the increase in flexural
strength and fracture toughness compared to leucite-reinforced
The manufacturer’s internal testing (Ivoclar Vivadent,
unpublished data, 2005) states the fracture toughness
(single-edge, V-notched beam testing) to be 2 MPa to 2.5
MPa m ½ and a modulus of elasticity of 95 GPa ± 5 GPa.
Bindl et al. 61 studied the fracture strength and fracture
pattern of three monolithic posterior crowns (lithium
disilicate, leucite glass and feldspathic ceramic) that have
a uniform thickness of 1.5 mm. They conventionally
cemented one half of the specimens while adhesively cementing
the other half on dies. For the conventionally
cemented crowns, load to fracture was 2,082 N, which
was significantly higher than that of the leucite glass or
feldspathic ceramic. When the specimens were adhesively
cemented to the die, the fracture load for the lithium
disilicate rose to 2,389 N, which was comparable to the
two other specimens. This study showed the strength of
the lithium disilicate when conventional cementing techniques
are employed. A manufacturer’s internal study comparing
the difference in failure load for monolithic and
bilayered crowns showed adhesively retained monolithic
lithium disilicate restorations had the highest load
to failure numbers. 66,67
The pressed form of the lithium disilicate has been shown
to have a modulus of elasticity ranging from 91 GPa 64
to 95 GPa ± 5 GPa (Ivoclar Vivadent, unpublished data,
2009). The flexural strength varies depending on the testing
method used. Using biaxial flexural strength tests
under dry and wet conditions, Sorenson et al. 65 found a
flexural strength ranging from 411.6 MPa to 455.5 MPa.
Monolithic Versus Bilayered Restorations27
Albakry et al. 64 measured
the biaxial strength with a
universal testing machine.
Twenty standardized disc
specimens (14 mm by 1.1
mm) were supported on
three balls and loaded with a
piston at a crosshead speed of
0.5 mm/min. until fracture.
The mean biaxial strength for
the lithium-disilicate specimen
was 440 MPa ± 55 MPa.
Depending on the testing
method, fracture toughness
of the lithium disilicate has
been shown to be at least or
greater than 3 MPa m ½ . Using
the indentation strength
technique, Guazzato et al. 66
found a fracture toughness
of 3 MPa m ½ . Albakry et
al. 67 measured the fracture
toughness of the pressed
lithium disilicate using two
different techniques: indentation
fracture and indentation
strength. They reported
a fracture toughness of
3.14 MPa and 2.5 MPa m ½ ,
Veneering Ceramic for
The coefficient of thermal
expansion of feldspathic
glass is closely matched to
alumina-based core material
(~7 ppm/degrees Celsius to
8 ppm/degrees Celsius) and,
consequently, can be used as
a veneering ceramic. Leucite
layering ceramics have the
same coefficient of thermal
expansion as the leucite core
material, therefore, posing
no problems in coefficient
mismatch. However, the coefficient
of thermal expansion
of lithium disilicate is
greater than 10 ppm/degrees
Celsius. As a result, a new
compatible layering ceramic
Comparison of the Flexural Strength of Pressed Ceramics
Figure 9: Comparison of different crown combinations
using different materials and monolithic lithium disilicate
during a cyclic loading test.
Restorative dentistry is
the science and art of
replacing human tooth
structure. The tooth is
comprised of enamel and
dentin, which individually
are low-strength materials
but, when combined,
their bond is unique and
can survive a lifetime.
Technology has not been
able to replicate nature’s
was developed. 26 The layering
material (IPS e.max
Ceram) is a low-fusing nanofluorapatite
glass ceramic. It
can be used with either the
pressed or CAD/CAM version
of the lithium disilicate
core and does not contain
feldspar or leucite.
The light refraction gives the
lithium disilicate material
a natural appearance and
can be used in a monolithic
form. In this state, the flexural
strength remains throughout
the entire restoration.
Surface colorants are available
to obtain the final shade
When in-depth characterization
is desired, a partiallayering
technique can also
be employed. At this point,
it can no longer be considered
monolithic because it
still comprises a majority
of the structure compared
to the zirconia-based restoration,
in which the bulk
of the restoration is the
veneered ceramic. A manufacturer’s
cyclic loading study compared
dental materials for crowns
with monolithic lithium disilicate
crowns with and without
layered veneering porcelain.
68 After 300,000 cycles,
only the monolithic lithium
disilicate restorations —
regardless of whether layering
veneer porcelain had
been applied — did not
show any breakdown (Fig. 9).
Restorative dentistry is the
science and art of replacing
human tooth structure. The
tooth is comprised of enamel
and dentin, which individu-
ally are low-strength materials but, when combined, their bond is unique and can survive a lifetime. Technology has
not been able to replicate nature’s bioengineering. For many decades, the ceramo-metal crown has been the mainstay
of restorative dentistry. Recently, the zirconia-based ceramic restoration was introduced with better esthetics and core
strength. Both systems are bilayered restorations with the bulk of the restoration consisting of a veneered feldspathic
ceramic or a leucite-reinforced, low-fusing pressed ceramic. In either case, the strength is dependent on the bond
strength at the interface between the core and its ceramic veneer. A new approach has been described in which a
ceramic with excellent optical properties and high flexural strength can be used in a monolithic design. The resulting
restoration possesses these qualities throughout its entirety as opposed to a restoration based on a bond between two
dissimilar materials — the layering ceramic and the core — in which bond strength is less than the individual parts of
the crown. Because nature’s bilayered tooth structure cannot be replicated, a monolithic approach may be the future. CM
The author would like to thank Ruth Egl, RDH, for her editorial contribution and to acknowledge Kramer Helvey for
Dr. Gregg Helvey is an AGD Master and part of an elite group of dentists who are also skilled ceramists. Contact him at 540-687-5855, www.gregghelveydds.com or
1. Özcan M. Fracture reasons in ceramic-fused-to-metal restorations. J Oral Rehab. 2003;30(3):265–69.
2. Spear F, Holloway J. Which all-ceramic system is optimal for anterior esthetics? J Am Dent Assoc. 2008;139(suppl 4):19S–24S.
3. Imbeni V, Kruzic JJ, Marshall GW, et al. The dentin-enamel junction in preventing the fracture of human teeth. Nat Mater. 2005;4(3):229–32.
4. Lacy AM. The chemical nature of dental porcelain. Dent Clin North Am. 1977;21(4):661–67.
5. Naylor PW. Introduction to Metal-Ceramic Technology. Chicago, Ill: Quintessence Publishing Co. 1992:83.
6. Hin TS. Engineering Materials for Biomedical Applications. Hackensack, NJ: World Scientific. 2004:5–13.
7. Mitchell L, Brunton D. Oxford Handbook of Clinical Dentistry. New York, NY: Oxford University Press. 2005:694.
8. Fairhurst CW, Rodway JM Jr, Twiggs SW, et al. In: Smothers W, ed. Proceedings of Conference on Recent Developments in Dental Ceramics: Ceramic Engineering
and Science Proceedings. 2008;6(1/2):66–83.
9. Ferracane JL. Materials in Dentistry: Principles and Applications. 2nd edition. Philadelphia, PA: Lippincott Williams and Wilkins. 2001:161.
10. Fischer J, Stawarczyk B, Tomic M, et al. Effect of thermal misfit between veneering ceramics and zirconia frameworks on in vitro fracture load of single crowns.
J Dent Mater. 2007;26(6):766–72.
11. Bagby M, Marshall SJ, Marshall GW Jr. Metal ceramic compatibility: a review of the literature. J Prosthet Dent. 1990;63(1):21–25.
12. McLean JW. The Science and Art of Dental Ceramics. Volume II: Bridge Design and Laboratory Procedures in Dental Ceramics. Chicago, Ill: Quintessence. 1980.
13. Yamamoto M. Metal-Ceramics. Principles and Methods of Makoto Yamamoto. Chicago: Quintessence. 1985.
14. Murakami I, Schulman A. Aspects of metal-ceramic bonding. Dent Clin North Am. 1987;31(3):333–46.
15. Coornaert J, Adriaens P, de Boever J. Long-term clinical study of porcelain-fused-to-gold restorations. J Prosthet Dent. 1984;51(3):338–42.
16. Strub JR, Stiffler S, Schärer P. Causes of failure following oral rehabilitation: biological versus technical factors. Quintessence Int. 1988;19(3):215–22.
17. Hankinson JA, Cappetta EG. Five years’ clinical experience with leucite-reinforced porcelain crown system. Int J Periodontics Restorative Dent. 1994;14(2):
18. Kelsey WP 3rd, Cavel T, Blankenau RJ, et al. Four-year clinical study of castable ceramic crowns. Am J Dent. 1995;8(5):259–62.
19. Sherrill CA, O’Brien WJ. Transverse strength of aluminous and feldspathic porcelain. J Dent Res. 1974;53(3):683–90.
20. Dauskardt RH, Marshall DB, Ritchie RO. Cyclic fatigue-crack propagation in magnesia-partially-stabilized zirconia ceramics. J Am Ceram Soc. 1990;73(4):
21. Lamon J, Evans AG. Statistical analysis of bending strengths for brittle solids: a multiaxial fracture problem. J Am Ceram Soc. 1983;66(3):177–82.
22. Oram DA, Davies EH, Cruickshank-Boyd DW. Fracture of ceramic and metalloceramic cylinders. J Prosthet Dent. 1984;52(2):221–30.
23. Evans D, Barghi N, Malloy CM, et al. The influence of condensation method on porosity and shade of body porcelain. J Prosthet Dent. 1990;63(4):380–89.
24. Llobell A, Nicholls JI, Kois JC, et al. Fatigue life of porcelain repair systems. Int J Prosthodont. 1992;5(3):205–13.
25. Powers JM, Sakaguchi RL. Craig’s Restorative Dental Materials. 12th ed. St. Louis, Mo: Mosby. 2006:469.
26. Scolaro JM, Pereira JR, do Valle AL, et al. Comparative study of ceramic-to-metal bonding. Braz Dent J. 2007;18(3):240–43.
27. Chong MP, Beech D. A simple shear test to evaluate the bond strength of ceramic fused to metal. Aust Dent J. 1980;25(6):357–61.
28. Sced IR, McLean JW. The strength of metal-ceramic bonds with base metals containing chromium. A preliminary report. Br Dent J. 1972;132(6):232–34.
29. Mackert JR Jr, Parry EE, Hashinger DT, et al. Measurement of oxide adherence to PFM alloys. J Dent Res. 1984;63(11):1,335–40.
30. Herø H, Syverud M. Carbon impurities and properties of some palladium alloys for ceramic veneering. Dent Mater. 1985;1(3):106–10.
31. Joias RM, Tango RN, Junho de Araujo JE, et al. Shear bond strength of a ceramic to Co-Cr alloys. J Prosthet Dent. 2008;99(1):54–59.
32. Akova T, Ucar Y, Tukay A, et al. Comparison of the bond strength of laser-sintered and cast base metal dental alloys to porcelain. Dent Mater. 2008;24(10):
Monolithic Versus Bilayered Restorations29
33. Haselton DR, Diaz-Anold AM, Dunne JT Jr. Shear bond strengths of two intraoral porcelain repair systems to porcelain or metal substrates. J Prosthet Dent.
34. Coornaert J, Adriaens P, De Boever J. Long-term clinical study of porcelain-fused-gold restorations. J Prosthet Dent. 1984;51(3):338–42.
35. Özcan M, Niedermeier W. Clinical study on the reasons and location of the failures of metal-ceramic restorations and survival of repairs. Int J Prosthodont.
36. Dündar M, Özcan M, Gökçe B, et al. Comparison of two bond strength testing methodologies for bilayered all-ceramics. Dent Mater. 2007;23(5):630–36.
37. Grossman DG. Cast glass ceramics. Dent Clin North Am. 1985;29(4):725–39.
38. Venkatachalam B, Goldstein GR, Pines MS, et al. Ceramic pressed to metal versus feldspathic porcelain fused to metal: a comparative study of bond strength. Int
J Prosthodont. 2009;22(1):94–100.
39. Metal-Ceramic Bond Characterization (Schwickerath Crack Initiation Test), ISO 9693. Geneva, Switzerland: International Organization for Standardization; 1999.
40. Luthardt RG, Sandkuhl O, Reitz B. Zirconia-TZP and alumina-advanced technologies for the manufacturing of single crowns. Eur J Prosthodont Rest Dent.
41. Aboushelib MN, de Jager N, Kleverlaan CJ, et al. Microtensile bond strength of different components of core veneered all-ceramic restorations. Dent Mater.
42. Aboushelib MN, Kleverlaan CJ, Feilzer AJ, et al. Microtensile bond strength of different components of core veneered all-ceramic restorations. Part II: zirconia
veneering ceramics. Dent Mater. 2006;22(9):857–63.
43. Sailer I, Fehér A, Filser F, et al. Prospective clinical study of zirconia posterior fixed partial dentures: three-year follow-up. Quintessence Int. 2006;37(9):41–49.
44. Sailer I, Fehér A, Filser F, et al. Five-year clinical results of zirconia frameworks for posterior fixed partial dentures. Int J Prosthodont. 2007;20(4):383–88.
45. Kosmac T, Oblak C, Jevnikar P, et al. The effect of surface grinding and sandblasting on flexural strength and reliability of Y-TZP zirconia ceramic. Dent Mater.
46. Guazzato M, Quach L, Albakry M, et al. Influence of surface and heat treatments on the flexural strength of Y-TZP dental ceramic. Dent Mater. 2005;33(1):9–18.
47. Fischer J, Grohmann P, Stawarczyk B. Effect of zirconia surface treatments on the shear strength of zirconia/veneering ceramic composites. Dent Mater.
48. Vita Zahnfabrik. Veneering material Vita VM9 [instructions]. Bad Säckingen, Germany: Vita Zahnfabrik; 2007.
49. Vult von Steyern P, Carlson P, et al. All-ceramic fixed partial dentures designed according to the DC-Zirkon technique. A two-year study. J Oral Rehabil.
50. Raigrodski AJ, Chiche GJ, Potiket N, et al. The efficacy of three-unit zirconium-oxide-based ceramic fixed partial dental prostheses: a prospective clinical pilot
study. J Prosthet Dent. 2006;96(4):237–44.
51. Sailer I, Pjetursson BE, Zwahlen M, et al. A systematic review of the survival and complication rates of all-ceramic and metal-ceramic reconstructions after an
observation period of at least three years. Part II: fixed dental prostheses. Clin Oral Implants Res. 2007;18(suppl 3):86–96.
52. PFM vs zirconia restorations — how are they comparing clinically? Gordon J. Christensen Clinicians Report. 2008;1(11):1–2.
53. Taskonak B, Yan J, Mecholsky JJ Jr, et al. Fractographic analyses of zirconia-based fixed partial dentures. Dent Mater. 2008;24(8):1077–82.
54. Aboushelib MN, Kevelaan CJ, Feilzer AJ, et al. Effect of zirconia type on its bond strength with different veneer ceramics. J Prosthodont. 2008;17(5):401–08.
55. Guess PC, Kulis A, Witkowski S, et al. Shear bond strengths between different zirconia cores and veneering ceramics and their susceptibility to thermocycling.
Dent Mater. 2008;24(11):1556–67.
56. Land CH. Porcelain dental art. Dent Cosmos. 1903;45:437–44.
57. O’Brien WJ. Dental Materials: Properties and Selection. Chicago, Ill: Quintessence; 1989:408.
58. Giordano R. Materials for chairside CAD/CAM-produced restorations. J Am Dent Assoc. 2006;137(suppl 1):14S–21S.
59. Seghi RR, Sorensen JA. Relative flexural strength of six new ceramic materials. Int J Prosthodont. 1995;8(3):239–46.
60. van Noort R. Introduction to Dental Materials. Philadelphia, Pa: Elsevier; 2002:244.
61. Bindl A, Lüthy H, Mörmann WH. Strength and fracture pattern of monolithic CAD/CAM-generated posterior crowns. Dent Mater. 2006;22(1):29–36.
62. Hill TJ, et al. Cementation Effect on the Fracture Load of Two CAD/CAM Materials. 2009; Miami, FL: IADR. Abstract #0052.
63. Dasgupta T, et al. Fracture Load of Two PFM Veneering Techniques. 2008; Toronto, Canada: IADR. Abstract #2323.
64. Albakry M, Guazzato M, Swain MV. Biaxial flexural strength, elastic moduli, and x-ray diffraction characterization of three pressable all-ceramic materials.
J Prosthet Dent. 2003;89(4):374–80.
65. Sorenson JA, Berge HX, Edelhoff D. Effect of storage media and fatigue loading on ceramic strength. J Dent Res. 2001;79:217.
66. Guazzato M, Ringer SP, Albakry M, et al. Strength, fracture toughness and microstructure of a selection of all-ceramic materials. Part I. Pressable and alumina
glass-infiltrated ceramics. Dent Mater. 2004;20(5):441–48.
67. Albakry M, Guazzato M, Swain MV. Fracture toughness and hardness evaluation of three pressable all-ceramic dental materials. J Dent. 2003;31(3):181–88.
68. Guess PC, Zavanelli R, Silva NR, Thompson VP. Clinically relevant testing of dental porcelains for fatigue and durability with an innovative mouth motion simulator.
Presented at: 39th Annual Session of the American Academy of Fixed Prosthodontics. February 2009; Chicago, IL.
Reprinted by permission of AEGIS Publications. Helvey G. Monolithic versus bilayered restorations: a closer look. Vistas Complete & Predictable Dentistry.
Interview with Dr. David Hornbrook
– INTERVIEW of David S. Hornbrook, DDS, FAACD
by Michael C. DiTolla, DDS, FAGD
It was my pleasure to interview one of my clinical mentors, Dr. David
Hornbrook, for this issue of Chairside magazine. David is someone whom
I have followed since I graduated from dental school, when I started taking
his courses at Las Vegas Institute for Advanced Dental Studies (LVI),
PAC~live and the Hornbrook Group. Over the years, I’ve continued to
follow David and look up to him as a clinician and friend.
Interview with Dr. David Hornbrook33
Dr. Michael DiTolla: Good morning, David, it’s wonderful to have you here
Dr. David Hornbrook: Thanks, it’s great to be included.
IPS e.max has filled an
existing void in dentistry.
It is a highly esthetic
material — as you mentioned,
it approaches the
esthetics of anything we
have in dentistry right
now — and it’s amazingly
strong. We now have a
ceramic that’s four times
stronger than the ceramic
we’ve put on PFMs for
the last 60 years.
MD: People always say, “Now is the best time to be a dentist.” (With perhaps the
exception of the 1960s, before the air-driven handpiece was invented and everything
was belt-driven.) But as I reflect on my more than 20 years in practice, it seems
that things just continue to get better. Do you feel that 2011 is a great time to be
DH: Absolutely. There are two things we need to look at. One is, obviously,
that the economy has changed a little bit. There may be people reading this
who say, “I’m not doing what I was doing two years ago in smile designs and
discretionary dentistry.” But if we eliminate that aspect of it, this is the best
time to be a dentist.
The advantage of where we are now is that we are no longer faced with the
many limitations and compromises we’ve historically faced during treatment
planning. Materials are more esthetic, and adhesive dentistry has allowed us
to be more conservative. Today, the only limitations we face are those of the
MD: Well, let’s back up to what you said about the economic slowdown. I can tell
you that, at least from the lab’s perspective, the economic slowdown over the past
two years did happen — you are right on the money. If we look at our veneer sales,
they definitely decreased over that time period. No one is imagining that. This isn’t
a rumor running rampant through dentistry; there was a serious cutback in the
number of elective cosmetic procedures.
Over the past two years here at the lab, only a couple of products have grown.
One of them is an esthetic product (in the sense that it’s a great-looking product):
IPS e.max ® (Ivoclar Vivadent; Amherst, N.Y.) crowns. IPS e.max veneers have grown
as well. People obviously still need full-contour restorations, so those may not be
elective. At any rate, IPS e.max has continued to show an impressive growth curve
over the last couple years. I’m guessing you’re a pretty big fan of this product. Tell
me a little bit about the impact IPS e.max has had on your practice.
DH: You are absolutely right to say that I’m a big fan of IPS e.max. It’s an
unbelievable material. For those readers who aren’t familiar with this product,
IPS e.max is a lithium disilicate material that can be waxed and pressed or
fabricated using CAD/CAM.
When waxed and pressed, kind of like we’ve done with IPS Empress ® (Ivoclar
Vivadent) and leucite-reinforced ceramics for the past 20 years, we use the
lost-wax process (just like we’d cast gold). It can also be made using CAD/
CAM technology, whether in the office with CEREC ® (Sirona Dental Systems;
Charlotte, N.C.) or E4D (D4D Technologies; Richardson, Texas), or in the dental
IPS e.max has filled an existing void in dentistry. It is a highly esthetic material
— as you mentioned, it approaches the esthetics of anything we have in
dentistry right now — and it’s amazingly strong. We now have a ceramic that’s
four times stronger than the ceramic we’ve put on PFMs for the last 60 years. I
mentioned earlier about options in treatment planning: Now I can look at even
a second molar on a bruxer that has decreased vertical dimension and give the
patient a restoration that is esthetic, conservative and strong.
MD: I distinctly remember placing my first IPS e.max crown.
It was on a friend’s wife, and it was at the end of a two-year
period in which I did nothing but zirconia-based restorations.
We were struggling to blend the zirconia restorations
with the adjacent teeth because we were dealing with coping
shade issues and with dentists under-reducing teeth, especially
in the gingival third.
When lithium disilicate came out, I must admit I was a little
suspect. Ivoclar was releasing this material for the third time,
and I wondered if it would work. The first IPS e.max crown
I put in was so beautiful that it blew me away. It was the
kind of thing you looked at and said, “Wow. If this is going
to stand up to the types of wear and tear we see in the mouth,
this material is going to be successful.”
How neat is it that a material can be used for almost any clinical
indication — inlays, onlays, crowns and even veneers?
I recently heard a rumor that some of the esthetic institutes
were thinking of switching over to IPS e.max veneers. What
are you teaching in your clinical course now, and how do
you feel about IPS e.max veneers?
DH: Well, by the time this article is published, my opinion
may change based on the fact that Ivoclar is introducing
even better ingot and block shades. I know some people
will read this and say: “IPS e.max? It’s kind of gray. It’s
kind of opaque. It doesn’t look as good as IPS Empress …”
That was the IPS e.max of a year and a half ago, when
Ivoclar didn’t have available the many translucent and
esthetic ingots that are now offered for CAD/CAM or for
pressing. And now they’ve introduced ingots that mimic
what we’ve always seen with Empress, which is what I
would call my standard for anterior esthetics. To answer
your question, today I’m still a fan of IPS Empress in the
anterior and it is still my “go to” material. If you came into
my office or into my teaching center and you were going
to do six, eight, 10 veneers, IPS Empress would still be my
first choice. I just think it interacts with light a little better
than lithium disilicate. But as we get more experience
with the new Value ingots, that preference may change. I
seated 10 maxillary anterior veneers this week using the
new V1 ingot, and the case was beautiful.
We are also now doing prepless and very minimal-prep
IPS e.max veneers, because at 0.2 mm or 0.3 mm thin,
this material exhibits incredible marginal integrity. Even
being this thin, they are very high strength and very easy
for the laboratory to finish down at the margins. We’re
doing anterior 3-unit bridges in IPS e.max, and we’re getting
esthetics that approach IPS Empress. So we’re still
teaching IPS Empress. But, then again, three months from
now when you ask me this question I might say, “Who’s
using IPS Empress anymore? Not me.” This is what makes
dentistry so exciting and fun!
MD: My personal viewpoint is that if I’ve got to do a veneer
on tooth #9, and tooth #8 is a virgin tooth, I am going to use
IPS Empress. Like you, I don’t think there’s anything as lifelike
as IPS Empress somewhere between 0.3 mm and 0.6 mm
thick. It just looks more like natural tooth structure than anything
else. But I’ve started to change a little bit — and I’m
not as demanding esthetically as you are. When I get to an
8-unit veneer case, I like the idea — and we can see from
the numbers that dentists liked the idea, too — of having a
veneer material that’s three times as strong as IPS Empress.
Dentists have had problems with chipping and they’ve had
some breakage. Maybe it was due to poor prep design or not
checking the occlusion close enough, but dentists seem to like
the idea of having a stronger material. And, of course, when
you have six, eight, 10 veneers lined up next to each other, it’s
not the same kind of thing as it is with a single tooth. Do you
think that’s a reasonable approach for the average dentist?
DH: Absolutely. Not even for the average dentist — every
dentist. If we can deliver a restoration that is two to three
times stronger than anything else we can offer and it
doesn’t compromise esthetics, I think that’s definitely the
way to go. We’re looking at this material very seriously. I
mentioned that Ivoclar just introduced its IPS e.max Press
Impulse Value ingots. I did another case recently using
these V ingots — two cantilever bridges replacing laterals
off the canine and then eight other veneers — and it
was absolutely beautiful. I actually had the lab make two
sets: one IPS Empress and one IPS e.max. After trying in
both cases, I chose IPS e.max. Needless to say, we’re very
excited about this material.
MD: I agree, and dentists are certainly voting here at the
laboratory with their wallets, as well.
I remember one morning about a year ago, I opened a journal
and there was Dr. David Hornbrook doing a no-prep
veneer case! I wasn’t sure if this was a hostage situation in
which you had a gun to your head, but I was caught so off
guard that I spilled my coffee; I didn’t know what might have
prompted this. I have a feeling it’s material advancements.
And, of course, as somebody who performs such esthetic services
as yourself, the abuse of the no-prep veneer concept was
probably something that bothered you a little bit. But I really
thought it was a great sign. And you — being so open-minded
to go forward and try one of these cases, and then publish
the case! It was a gorgeous case, by the way.
DH: Well, thank you. I think prepless or very minimalprep
veneers are a technique that every dentist needs
to explore. Obviously, it’s public-driven because a major
dental manufacturer markets prepless veneers to the public,
so now patients are asking for this procedure. But I
think it’s been abused. We see very compromised results
with this technique more often than not. You work with
a dental laboratory, so you understand the importance of
the communication process. The communication between
the ceramist and the dentist is so crucial. I think a lot of
Interview with Dr. David Hornbrook35
dentists were, and still are, doing these prepless veneer
cases without really understanding the indications and
contraindications of this procedure, and we see some really
ugly and even unhealthy cases, especially tissue-wise.
I practice dentistry three to four days a week, and my
patients were asking about these prepless veneer cases.
And I really wanted to explore this more closely: Was it
the material itself, the lack of case planning or the technique?
So I went back and worked with laboratories and
materials and ideal cases. Together we established some
planning protocols that have yielded some surprisingly
unbelievable results, esthetically and functionally, with
prepless veneer cases. It’s an opportunity available for
patients and doctors. As I teach, I find that a lot of doctors
refuse to prep virgin enamel. This refusal limits their ability
to offer their patients some beautiful smiles. Prepless
veneer cases, when planned properly, are a viable alternative
to prepped veneers.
MD: That’s interesting. I’ve never heard a dentist say, I refuse
to prep virgin enamel. If somebody were to make that argument,
I would have to assume they were probably doing lots
of inlays and onlays. We certainly see lots of virgin enamel
on very healthy cusps being prepped in the name of insurance-approved
crown & bridge. I don’t know why they would
find it to be different just because it was in the anterior. You
know what I mean?
DH: I totally agree. But I hear and see it all the time. I see
dentists who will prep a full crown instead of an inlay. Or
they’ll prep virgin teeth on each side of a missing tooth to
place a 3-unit bridge, but they won’t do a 0.5 mm depth
cut on an anterior tooth. It amazes me.
MD: To me, no-prep veneers really are a great finishing
technique. I do hardly any no-prep cases where all eight or
10 units are no-prep veneers. But I do see cases where we
will replace, say, old PFMs on tooth #7 through tooth #10
with some IPS e.max crowns. And then I will place no-prep
veneers on the cuspids and the bicuspids and finish out the
whole smile without having to do any additional preparation.
That’s what I mean by a finishing technique: It is a
great way to finish out a smile when it’s done in conjunction
with other restorations.
DH: I agree, especially in this baby boomer age. A lot
of these people went through ortho as a teenager and
had their first bicuspids extracted. Now their posterior
quarters are collapsing and they want a nicer looking
anterior smile because of wear or discoloration. You
can do veneers, or you can replace existing crowns and
then place very conservative veneers on the premolars
and develop a beautiful smile.
MD: When I first learned about esthetic techniques in your
courses (back in 1995), we were doing fairly aggressive
preparations in the dentin when placing IPS Empress
veneers. And, as time has gone on, I have found that because
of improvements in ceramic materials, we can achieve similar
results with less reduction, assuming that the tooth is not
way out of an ideal arch form and it’s just an esthetic issue.
I like the idea of minimal-prep veneers, which, to me, is
something that has all the margins still in enamel. I like the
idea of bonding to enamel and keeping it intact. Do you
find that minimal-prep veneers, where you’re not necessarily
exposing dentin, are something that you are using more on
a day-to-day basis?
DH: When I first started teaching, around the time you
went through my courses, I think it was also the inexperienced
ceramist who established some of the “ideals” of
veneer preparation. IPS Empress was new to ceramists. It
was a monolithic material. They didn’t really understand
how to use the different opacities and translucencies in a
very thin environment. So they said, give us some more
room because we just don’t get it. And we would prep
0.7 mm to 1 mm, and they would want the contacts
broken. It was a new concept to them. We were teaching
very aggressive preps in the mid 1990s. In the last four
or five years, we’ve really done an about face. And what
we recommend now is 0.3 mm to 0.5 mm depth cuts,
assuming that the tooth is ideally positioned in the arch.
So, unlike in the past, when most of my preparation for a
veneer was in dentin, most of it’s now in enamel.
MD: Do you find that you enjoy bonding to enamel more
than dentin, or is it not a big issue for you? I hear from dentists,
whether it’s postoperative sensitivity or not being sure
how much they’re supposed to dry the tooth off, that they
really like the idea of etching enamel. Being able to dry it
to your heart’s content, see that nice frosty look. For those
of us who are kind of old-school dentists, it feels comfortable
in a sense. It’s something that we grew up with.
DH: Personally, I don’t really have a problem bonding
to dentin. We’ve been doing it for almost 15 years, and
I feel the predictability is there. But, I agree: I think that
dentists still struggle, even to this day, with this whole
total-etch and how wet is wet and how dry is dry concept.
Most clinicians feel a little more comfortable being able to
etch, rinse and dry as much as they want and get success.
I think we’re going to see increased predictability, less
standard deviation and less failure when the restoration
is primarily in enamel.
MD: I actually think that we’ll see more of these restorations
diagnosed. Obviously, there’s talk of over-diagnosis of
veneers, but I think that’s by a small percentage of dentistry.
Many dentists still don’t talk about this type of esthetic dentistry
because they’re not totally confident in their ability to
get a great non-sensitive result doing it completely on dentin.
They seem to like the idea of bonding to enamel, and
they know it works, and they get less post-op sensitivity. As a
esult, they’re going to be more confident in their procedures.
DH: I agree with you.
MD: Speaking of total-etch versus self-etch, for your direct-placed restorations in
the posterior, are you using self-etch at all? Or are you still a total-etch guy?
DH: I’m definitely a total-etch guy! In fact, I’ve actually gone back to fourth
generation dentinal adhesive systems. So, I etch, and then utilize a separate
solution for the hydrophilic primer and a separate solution for the hydrophobic
MD: So you’re back to the regular two-bottle system. What are you using?
DH: I’m using ALL-BOND 3 ® (Bisco Inc; Schaumburg, Ill.). I like Bisco products
and respect Dr. Byoung Suh and the research being done at his company.
If I look back historically, what I would consider the gold standard would be
ALL-BOND 2 and OptiBond ® FL (Kerr Corporation; Orange, Calif.). And the
only problem, at least that I saw, primarily as an educator, was that ALL-BOND
2 was acetone-based, so it was a little more finicky. What Bisco did a few years
ago was change the hydrophilic carrier to alcohol. Now we have what I would
consider a new gold standard. It’s alcohol based, and you can use it for every
type of restoration you place in your office. Too many clinicians have too many
bonding agents in their refrigerator. Unless they can get an adequate amount
of light to polymerize the material, anything but a fourth-generation adhesive
will lead to a compromised result.
MD: It really is kind of funny. I don’t know how many times in dentistry we’ve seen
dentists take a step backward from what the latest and greatest is, with maybe the
exception of digital impressions, which tend to be more difficult and more timeconsuming
than conventional impressions. You look at the way things went to one
bottle and then all of a sudden we have self-etching in one bottle. It began to look
like, “Wait a minute. Are we doing this for us, are we doing this for the quality, or
are we doing this for our patients?” So it’s interesting to hear that you’ve gone back
to something that’s time tested and proven. It does take a little more time, but you
feel it’s better. I know you’re not going to go back to a self-cure composite instead of
light-cure composites or a belt-driven handpiece. You must really feel in your heart
that this is the right thing to do.
DH: I do. I have not seen the sensitivity that a lot of people saw with the
total-etch. Obviously, we’re isolating and controlling that surface moisture, not
over-etching the dentin. But it’s something where I have predictability; I have
success; I don’t have much postoperative sensitivity; I don’t see premature
failure; and I can look back and show you 15 years of clinical experience, as
well as excellent research.
The problem with today’s bonding agent chemistry is that it changes too fast.
You’ll see a study on a self-etching primer that bonds to enamel that was carried
out over a period of 36 months, and that material has changed chemistry
since the article came out. So we can’t look at these and say this is going to
have long-term success, where we can with total-etch systems.
I hear and see it all the
time. I see dentists who
will prep a full crown
instead of an inlay. Or
they’ll prep virgin teeth
on each side of a missing
tooth to place a 3-unit
bridge, but they won’t
do a 0.5 mm depth cut
on an anterior tooth.
It amazes me.
What we recommend
now is 0.3 mm to 0.5 mm
depth cuts, assuming
that the tooth is ideally
positioned in the arch.
So, unlike in the past,
when most of my preparation
for a veneer was in
dentin, most of it’s now
MD: Does this mean that you have not played with any of the self-etching flowable
DH: I’ve played with them, but I haven’t used them clinically except to alleviate
sensitivity in gingival abfraction lesions.
Interview with Dr. David Hornbrook37
MD: Yeah, I get it. If they work, it seems like a huge step forward for a dentist to be
able to place things this quickly. But you always have to ask yourself: Is this about
what’s convenient for me or is it about what’s better for the patient? And it may be
different in the hands of the average dentist than it is for you.
The problem with today’s
bonding agent chemistry
is that it changes too
fast. You’ll see a study
on a self-etching primer
that bonds to enamel
that was carried out over
a period of 36 months,
and that material has
changed chemistry since
the article came out. So
we can’t look at these
and say this is going to
have long-term success,
where we can with totaletch
DH: Again, I personally think the problem with some of the self-etching resins,
and even the resin cements, is that the manufacturer can show us this great
data, but what does it really do clinically in an environment on a live, vital
tooth? I won’t name names, but there’s a product that is highly touted by the
manufacturer as the best self-etching resin cement on the market. When zirconium
oxide first came out, we had a lot of failures because we were using the
wrong layering material, until it failed. So I cut off 45 zirconium oxide crowns
utilizing this cement that supposedly bonded excellently to dentin. And every
single one I cut off, the cement just peeled away in large sheets. There was
zero bond. So we have got to ask ourselves: Are the materials that show great
benchtop success on non-vital teeth done in a controlled environment giving
us the same clinical success in the mouth in a very hostile environment?
MD: Right. And there is always going to be a disconnect between the two. I
think you may be in second place behind me for the number of zirconia restorations
cut off. I know I’ve cut off more than that. Some of the zirconia crowns
I’ve cut off have actually been our new BruxZir ® material. BruxZir is a monolithic
zirconia restoration that, shockingly, dentists are prescribing in record
numbers. Believe it or not, BruxZir actually passed IPS e.max in sales volume
in November 2010. The ongoing wear studies at a couple of universities look
encouraging, but you can imagine, having cut off zirconia-based crowns, what it
might be like cutting off a full-contour zirconia crown! I have always thought this
is something we need to talk about a little bit more. In fact, I remember you calling
me once and saying, “Well, what if you have to do endo through one of these
zirconia-based crowns?” And, at the time, we didn’t have a good set of diamonds.
But now we’ve found some good diamonds to be able to cut those off. Are you
using many zirconia-based restorations right now in your day-to-day practice?
DH: Lithium disilicate has replaced my zirconium oxide-supported crowns in
the posterior. At one of my most recent lectures, a ceramist said IPS e.max has
destroyed his Lava (3M ESPE; St. Paul, Minn.) market, which makes sense!
I still use zirconium oxide-supported crowns for posterior bridges and three
units in the anterior. I do pride myself on trying to be metal-free as much as
possible, and that’s the only option I have. But single units, whether it be full
zirconium oxide or zirconium oxide-supported with layering ceramic, I rarely
ever do those. I do IPS e.max.
MD: If you look at the history of indirect restorations in dentistry, of course cast
gold was the first material out there — a monolithic material. Then, porcelain
jacket crowns, which left a lot to be desired in terms of strength, but it was still just
one material. Even back in the 1960s, there became this need to have something
that was more esthetic than gold. We can talk about the current esthetic desires
in Southern California, but even back in the 1960s there became a need to take a
metal coping and fuse it to porcelain.
The PFM has been the workhorse of dentistry for the last 40 years. It’s driven American
dentistry, this laboratory, and almost all laboratories, for that matter. But
PFMs have always suffered from the problem of having porcelain bonded onto the
metal substructure. And with this bilayered restoration, there is always a chance
that something can go wrong. In fact, it’s rather amazing that a lot of the times
nothing did go wrong with the bond between the two. But, by nature, a bilayered
restoration is going to have more problems than a monolithic restoration. I think
we finally saw that with the ceramic-bonded-to-zirconia
market. Whether because of the coefficient of thermal expansion
or the way people were fusing the two parts in the oven,
there was going to be issues with compatibility and chipping.
So, we’ve seen the same thing: IPS e.max, a monolithic
material, and the monolithic BruxZir material introduced
after it have destroyed the zirconia market. Again, the
average dentist appears to be doing the same as you, at least
in that respect.
You’ve always struck me as a guy who would probably have a
CEREC ® (Sirona Dental Systems; Long Island, N.Y.) machine
in his practice. I’ve seen some of the artful direct composites
and killer temporaries you’ve done, and you’ve always work
with the best ceramists to get great results on your final restorations.
You really are as much of a lab tech as any GP I
know, but I don’t know that you ever fully embraced CEREC.
Do you have a unit now that I don’t know about?
DH: Actually, I do! But I’ve only had it for two weeks. I’ve
done only four crowns. I was waiting for the camera to
be better and for the software to be a little more intuitive
before I took the plunge. It has been worth the wait.
When the 3M ESPE Paradigm Block came out several
years ago, I was lecturing a lot on inlays and onlays. And
3M said: “Hey, we’ll send you a CEREC. Start doing the
Paradigm Block and when you love it, you’ll talk about
it.” Well, I hated the CEREC machine. It was so counterintuitive.
After three weeks, I sent it back and said, “I’m
not using this!”
MD: When was that?
DH: Maybe seven years ago? Whenever CEREC 3 came
out. But now I’m looking at the software and looking at
the camera, looking at the whole technology of digital
impressions (which is obviously the future of dentistry),
and it makes sense. You’re right in the fact that I do like
to play with ceramics, but I’m not nearly to the level of
expert ceramists. I can’t make a veneer or an anterior
crown look the way they can. But the fact is we’re using
monolithic IPS e.max in the posterior where I’m not
having to cutback or layer because I want strength. I’m
getting good esthetics with monolithic material. After all,
the lab was just waxing and pressing or milling it to full
contour and superficially staining it. I thought, why am I
not doing that?
MD: I wasn’t praising you so much for veneers; I was complimenting
your anterior direct temporaries. I would never
take an impression and send it to you and say, “Hey, make
DH: I wouldn’t either!
MD: But I’ve seen what you can do on posterior teeth with
direct composite, and it did seem like you are the kind of
guy who would mill IPS e.max restorations in the posterior.
You’ve always offered such great services to your patients.
At Glidewell, we’ve now got six CEREC machines and probably
10 additional MC XL mills. I’ve got a CEREC AC in the
operatory and I am convinced — here I am practicing in a
lab, but regardless — I am convinced that one-appointment
dentistry is better than two-week dentistry.
DH: I’ve only done four of these, so I’m not great at it
yet. It’s like, how do I schedule it? One to two hours for a
single unit? How long is it going to take me? But for the
people who are great at it, I think it’s a huge advantage.
I see this technology as an advantage for even a three- or
four-day turnaround versus two weeks. Yes, we’re good
at making temporaries; that’s what we’ve always done,
and we’re good at it. But if we use this technology, we get
reduced lab costs, improved turnaround time (whether
that be 1.5 hours or three days) and total control.
Let me give you an example. On the third CEREC crown
that I did, an IPS e.max crown, I decided to try it in and
adjust occlusion in the blue block state before it was sintered.
And the patient bit down and broke the crown! In
the past, had I sent that crown to Glidewell and it was
IPS e.max or IPS Empress, I would have made a temporary,
sent it back, and you would have made me a new
one. Well, the cool thing about CEREC is that it was in my
library. All I had to do was go back to the library, click
it again, and in eight minutes I had a new crown! That’s
where there is a huge advantage. Or say you have a material
that you put in and there is a marginal discrepancy.
Instead of taking a new impression, you can take a new
digital impression and do it in three minutes.
MD: I agree. That’s a better way to say it. I mean, it’s true:
I do believe that one-appointment dentistry is better than
two-week dentistry. But I also believe that three- or four-day
dentistry is better than two-week dentistry. And I believe twoweek
dentistry is better than six-week dentistry! The shorter
period of time between prep and seat the better because of
bacterial leakage, teeth shifting and factors like that.
DH: And also the fact that today we are doing more conservative
dentistry. The primary complaint with some of
the crazy little single-cusp replacement onlays that we do
is, how do you keep temporaries in? It’s a pain! If you
plan to see this patient in three weeks, more than likely
you’re going to see them twice in the next three weeks
to re-cement the temporary. And if I can do it as either a
single visit or get it back in two or three days because I
milled it myself, we’re not going to have problems with
MD: Right, because patients don’t want to come in three
times. And, frankly, you’ve blown any profit you might have
made on that case after three visits.
Interview with Dr. David Hornbrook39
It’s funny you mention reduced lab costs because here at the
lab we are all for that. We want to reduce lab costs. I mean,
of course we'd like to work with more dentists, but primarily
we’d like to reduce lab costs. We’re getting ready to release,
most likely at the Chicago Dental Society Midwinter Meeting,
a digital impression system that we will sell to dentists for
their practice. We’re looking at it as an IPS e.max/BruxZir
wand, if you will. So, for monolithic restorations, a dentist
would take a digital impression, which we realize is more
work than a regular impression. To me, to take a digital
impression if it’s not hooked to a mill is kind of silly, unless
it’s going to save you money. And some of the other digital
impression systems actually cost you money. It’s very difficult
for you to get any ROI with those systems.
With the Glidewell system, we’re talking about taking a digital
impression and sending it to the lab. Submitting the digital
impression this way saves the dentist $27 on the cost of the
restoration. There is no one-way shipping cost ($7 savings),
no cost for impression material ($10 savings), and the lab
discounts $10 because it can be digitally fabricated. So, we
do want to reduce lab costs to dentists by cutting out some of
the steps by making these model-free crowns.
You and other CEREC users have proven that model-free
crowns can be made, and Sirona has 25 years of experience
doing it. We know it works. Have you used many of the other
digital impression systems, such as Cadent iTero (The Cadent
Company; Carlstadt, N.J.) or Lava C.O.S.?
DH: I haven’t used Cadent clinically. I’ve played with it
chairside and it seems like one of the easier systems to
use. I know a lot of laboratories prefer it. And I like the
technology of the Lava C.O.S. system, but it’s very time
consuming. We looked at it, we were going to buy it, and
then we decided not to. As we talked to colleagues, some
of my friends that are excellent dentists, a lot of them
had sent it back. It’s not that it wasn’t accurate or that its
technology wasn’t cool. But if it takes 40 minutes to take
an impression, it’s not profitable.
You mentioned the cost savings of shipping, and that’s
something that a lot of dentists don’t look at. If they say,
oh, I only save $10 by doing that, what they don’t take
into account is the money saved in outgoing shipping.
They will also get a better turnaround time because instead
of taking two and a half days to get it to you, the
case arrives at the lab instantly.
MD: Exactly. I don’t like it when dentists are kind of force-fed
technology or when dentists are told they are not doing great
dentistry if they’re not using this technology. For example: On
your polyvinylsiloxane impressions, do you perceive that you
have a big problem with them day in and day out?
DH: Not a major problem, but I think that if you really
looked at the weakest link in the chain of restorative
dentistry, it would be the impression and the pour-up in
crummy dental stones. But is that going to keep my restorations
from lasting 10 years or more? No. We have more
accurate materials today than we did 20 years ago, when
dentists were doing gold crowns that were in the mouth
for 40 years. So, I totally agree with you on that.
MD: That’s why I feel that if the digital impression system
is not tied to a mill, where you can do same-day dentistry
or three- or four-day dentistry and save nearly $20 per IPS
e.max crown through a lab, what’s the point of going through
the extra effort to do something like this?
What are you using for a diode laser these days? And I’m
guessing you have a hard-tissue laser, as well?
DH: I use a diode every single day in my practice; we
have one in each operatory. As far as hygiene, I personally
think that use of a laser is standard of care. Dentistry
as a whole will realize that in a few years.
The advantages of present-day diodes compared to the
ones we used are that they are affordable and smaller.
You can get a good laser for less than $5,000; all of a sudden,
lasers are very affordable.
We’re also doing closed-flap osseous using an Erbium:YAG
laser (AMD LASERS, LLC; Indianapolis, Ind.), which is
very cool. So we’re performing crown lengthening without
laying a flap, and we’re getting unbelievable results.
Lasers, just like digital technology, are going to change
the way we practice dentistry as they become more
affordable and more dentists adopt the technology.
MD: Do you feel pretty confident with closed-flap crown
lengthening? I know it drives some periodontists crazy — it’s
hard to treat what you can’t see. But I have to say that biologic
width violations are a real problem. As you walk through the
laboratory and look at anterior models, you see interproximal
violations left and right. You know the crowns probably
look pretty good, but the tissue is purple interproximally
because the prep outline doesn’t follow the gingival outline.
Are you doing most of these in the anterior or posterior?
DH: I do it just in the anterior because I can tactfully feel
the bone and make sure I’m not troughing or creating an
artificial biologic width. Because posterior bone is thicker,
I don’t do it. I refer that out if it needs to be done. I
was keeping track of repercussions up to 2,500 teeth, and
then I stopped, but we’ve had zero repercussions. I’ve
done it in all my courses since 2004, and we’ve seen no
problems. The cool thing is that unlike traditional crown
lengthening, where a flap is laid and a diamond bur is
used on the bone and then you wait 12 to 16 weeks,
we’re prepping and impressing and provisionalizing on
the same day that we do our osseous. We’re doing some
fun, really cool things with that.
MD: Maybe in a perfect world every patient would be flapped and you’d see directly
what you were doing. But the reality is that most of these cases have biologic
width violations and dentists aren’t doing anything. They’re taking the old crown
off and putting a new crown on. If anything, the margin gets dropped just a little
bit further as the doctor goes in and cleans the cement off the prep, so the biologic
width violation gets a little bit worse. I think you’re seeing good results because it’s
a step in the right direction. It may not be 100 percent perfect, but maybe the patient
wouldn’t have had it done surgically anyway. I think that some treatment to
improve biologic width is better than no treatment at all.
DH: That’s right.
MD: You mentioned that you do closed-flap crown lengthening procedures during
your courses. Tell me a little about the courses that you’re putting on today.
DH: The best source for those who are interested in where I’m going to be as
far as a lecture or hands-on course is to visit www.davidhornbrook.com. Click
on “Calendar,” and it will go through the things we’re doing. I still do a lot of
full-day lectures across the country, and that’s actually ramped up because of
all the new materials. People are obviously not getting trained in dental school
on IPS e.max, prepless veneers and lasers. Now they’re hearing about it and
getting excited. It’s good for me because I’m getting out there more, and I enjoy
that aspect of my career.
We are still doing some live patient courses. As you mentioned, you went to
my esthetic courses when I was teaching at LVI. Then I formed P.A.C.~live
and the Hornbrook Group, which were also live-patient, hands-on treatment
courses. Now we’re doing it through a series called Clinical Mastery. Doctors
can go to www.clinicalmastery.com and see a list of the courses we’re offering,
including occlusion courses and full-mouth and anterior live patient courses,
in which dentists will bring their patients and their team.
We’re doing these courses primarily in Mesa, Ariz., at the new dental school
A.T. Still University – Arizona School of Dentistry and Oral Health (ATSU).
This is just a phenomenal dental school. It’s so different from where I went to
dental school. The faculty is very embracing, very technologically advanced.
In fact, I was talking to the school’s dean, Dr. Jack Dillenberg, and the school’s
recommendation for posterior restorations is composite, not amalgam. The
school only teaches amalgam so its students can get through the boards. It’s
very interesting how different it is. The faculty is teaching veneers, implant
placement, lasers. Students actually go through an entire laser curriculum. The
students are learning some very cool things.
MD: That’s a real education! That’s pretty impressive.
DH: It’s not that I’m pushing this particular school, but if a doctor who reads
this has children, relatives or friends who are thinking about going to dental
school, I would look at ATSU. They only have one specialty program in the
school — orthodontics — which means that graduating seniors leave dental
school having placed an average of 15 to 20 implants because there is no
periodontal program. The students are doing perio full-mouth surgery and
impacted wisdom teeth — they’re just doing some really cool things.
If you really looked
at the weakest link in
the chain of restorative
dentistry, it would be the
impression and the pourup
in crummy dental
stones. But is that going
to keep my restorations
from lasting 10 years or
more? No. We have more
accurate materials today
than we did 20 years ago,
when dentists were doing
gold crowns that were in
the mouth for 40 years.
MD: The better part of having no specialty programs is that there are no specialists
there to tell them that this stuff is too difficult for them to do, and they probably
shouldn’t try it. That was my dental school!
DH: Exactly, same with me. So we’re doing some cool things at ATSU. Again,
Interview with Dr. David Hornbrook41
dentists can find out more about those courses by visiting my website
www.davidhornbrook.com or www.clinicalmastery.com.
MD: I want to close by telling you a story. I’m not sure if I’ve told you this before,
but when we were together at LVI, I brought a patient …
DH: I remember the case! When you left retraction cord in there?
MD: Whoa, whoa, whoa, I didn’t leave retraction cord in there. What happened
was that the two IPS Empress crowns on tooth #8 and #9 were deeply subgingival.
We weren’t doing much soft tissue recontouring back then, and certainly no hard
tissue. But that’s really what this case needed. You said, “Let’s put some retraction
cord in to contain the gingival fluids when we bond these crowns into place.” Well,
I guess I was a little sloppy. I pulled the retraction cord out from tooth #8 after curing
the cement, but when I went to pull out the retraction cord on tooth #9, I had
bonded it into place. I tried to get it out and you tried to get it out. The good news
is that it was size 00. The bad news is that it was black, and I’d bonded it between
the crown and the tooth. You could see it through the patient’s thin tissue, and
you said to me, “Congratulations. You are the first dentist in history to do an allceramic
crown that has a gray margin like a PFM.” I’ve always been proud of that.
Later, that patient went snow skiing with his wife and she fell getting off the lift and
smacked him in the face with a ski pole. And he called me in a panic and said,
“My wife broke one of my front crowns off.” I asked which one and he answered,
“The one on the left (tooth #9).” I thought to myself, Hallelujah! Then he asked if he
should look for it. “Hell no!” I didn’t want to have to explain what the black string
was hanging off the crown.
So, your course and that experience were really instrumental in teaching me to pay
attention and really do things right. Dentistry has been a learning experience for
me, with this average set of hands I have.
David, I want to thank you for being there every step of the way and being very
generous with your time, especially for an interview like this.
DH: Thank you, Mike! It’s always great to hear your voice because I haven’t
talked to you in so long. You certainly have done so much for our profession,
and I consider you a mentor, a great friend, and I appreciate being asked. CM
Dr. David Hornbrook is a leading educator in esthetic dentistry. For information on his upcoming lectures and
hands-on courses, visit www.davidhornbrook.com or www.clinicalmastery.com.
– Article and Clinical Photos by
Ellis J. Neiburger, DDS and
Yehonatan L. Frandzel, FPH
A digital photo or radiograph may show a virtual
reality that is considerably different than actual
reality. Therefore, there is a need for the practitioner
to know how to detect virtual images and
distinguish them from reality.
Recent developments in digital imaging in dentistry and
easy-to-use editing software present many occasions for
altering or fraudulently changing digital images of products,
patients and their dental conditions, treatments and
radiographs. Though seemingly impossible to detect when
carefully done, there are numerous clues of digital editing
that can be detected by the observant practitioner.
In the last few years, more dentists and publications have
increasingly switched from standard film photography
and radiography to computer-generated digital techniques.
1–4 Digital photography (DP) and digital radiography
(DR) are produced by an electronic sensor linked to
a computer, which generates and manipulates the virtual
image either by light or X-ray exposure. Sophisticated
editing software can magnify, shade, duplicate and
infinitely change the image. 1–4
Image modification is not new. Since the 1870s, images
on photographic film have been manipulated to show desired,
artificial changes. 5,6 The creation of “spirit images,”
burning, dodging, airbrushing, cropping, reverse printing
and adding new subjects (e.g., a filled endodontic
canal or whiter teeth) on an existing photo image has
always been possible with photographic film. The famous
disappearances of “vanishing commissars” in photos from
Stalinist Russia, fantasy motion pictures (e.g., “Titanic” or
“Harry Potter”), TV shows and the “retouched” photos of
the many tabloid newspapers are prime examples. 4–6
Until recently, these changes were technologically demanding
and expensive to do. 6 Often they were done
poorly, showing obvious signs of manipulation. However,
with the advent of DP, DR and inexpensive, easy-to-use
editing software, quality changes are as simple and inexpensive
to achieve as pressing a computer key or pointing
a mouse. 4–6 Most photographers and publications will
use editing software to “clean up” images: from cropping
and eliminating red eye in portraits to repositioning the
Egyptian pyramids (National Geographic) in order to fit
the page better. 5 Many dentists and dental publications
do the same.
Today, a digital photo or radiograph may show a virtual
(false) reality that is considerably different than actual
reality. Therefore, there is a need for the practitioner to
know how to detect virtual (computer-generated) images
and distinguish them from reality. 7 The quality of treatment
and research, the descriptions of commercial products
and the desire for honest cosmetic predictions for
our patients depend on these skills.
Detecting Computer-Enhanced Dentistry47
What Digital Photography
Figures 1, 1f: Computer-generated extraction of deciduous tooth and creation of two restorations
Figures 2, 2f: Virtual endodontics, periapical healing and four restorations
Figures 3, 3f: Computer-created crown and three carious lesions (molars)
Popular software such as Adobe ®
Photoshop ® (San Jose, Calif.), Corel ®
PaintShop Photo ® Pro (Mountain
View, Calif.), Apple iPhoto (Cupertino,
Calif.), Google Picasa 3 (Mountain
View, Calif.), and hundreds of
bundled digital camera photo programs
have found their way into
many offices and homes. 6 If one
buys a digital camera, it most likely
comes with a functional editing program
that allows the manipulation of
photos. Using these programs, one
can cut, paste, erase, combine, overlay,
reshade and otherwise retouch
any photo taken. Patient photos can
be enhanced to show better-shaped,
positioned or whiter teeth and then
used as a marketing tool or prognostic
inducement for additional treatment.
Alternately, this means one can also
create decay, cracks and abscesses on
DR images of normal teeth in order
to mislead other professionals, thirdparty
payers and the courts. 1–4,7,8
DP and DR software allows the operator
to change the presence, shade,
color saturation, brightness and contrast
of bone or tooth structure in a
digital image. 4–6 Restorations, teeth
and pathology can be virtually created,
removed or modified in the
digital image. In some cases, this
activity may approach the level of
fraud, where images of restorations
or treatments (e.g., endodontics or
extractions) can be created by computer
and submitted as evidence in
trials or sent to third-party payers as
proof of actual diseased conditions
or previously billed treatments. 1–4,7
Figures 4, 4f: Virtual removal of root, bone healing and creation of a 3-unit fixed bridge
Figures 1–6 are digital images of actual
radiographs. Figures 1f–6f are
corresponding digital images that
have been edited to show pathologic
changes, healing and restorations
that have not actually occurred. They
are computer simulations.
Figure 1f shows computer enhancements
to Figure 1 where a tooth has
been virtually extracted, the bone of
the extraction socket partially healed
and two virtual restorations placed.
Note the root fragment left in Figure
Figure 2f shows a re-edited Figure 2
where virtual endodontic treatment
was performed, the periapical radiolucency
partially healed (smaller
size) and four restorations placed.
Nothing was really done except for
Figure 3 shows distal decay in the
upper second premolar and no other
decay. Figure 3f demonstrates a virtual
crown that “restored” distal caries
in the upper second premolar;
also note the virtual decay on the
upper second (distal) and third (mesial)
molars and mesial decay on the
lower second molar.
Figure 4f presents virtual treatment
of Figure 4 where a root appears to
have been extracted, partial healing
of the socket accomplished and a
3-unit fixed bridge made — all within
a few minutes of computer work.
Figure 5f shows the addition of an
extra endodontic filling and crown
on the first bicuspid of the perfectly
natural tooth in Figure 5.
Figure 6f shows whiter teeth than
what actually appears in Figure 6.
This can be used as proof of the
power of “Virtual Product X,” which
bleached the patient’s teeth in a few
seconds — except the active ingredient
came from the computer.
How to Detect Computer-
Sophisticated photos of dental products
and techniques are appearing in
dental literature in the form of advertisements
or research treatment
results. Many of these images are
computer-generated and retouched.
Figures 5, 5f: Computer-generated endodontics and crown on first premolar
Figures 6, 6f: Virtual tooth whitening
Sophisticated photos of dental
products and techniques are
appearing in dental literature in the
form of advertisements or research
treatment results. Many of these
images are computer-generated
Detecting Computer-Enhanced Dentistry49
If it looks too good to be true, it probably is. Wild
claims that defy your own experience can indicate
potential computer editing. Perfect margins, shading,
alveolar bone regrowth and other signs of perfection
should raise questions.
The discriminating practitioner must be able to identify
the virtual from the real so that he or she can view the
material presented on a sound, accurate scientific basis,
rather than a virtual basis. There are a number of classic
techniques one can use to detect computer enhancements
in digitally produced photos and radiographs.
If it looks too good to be true, it probably is. Wild
claims (supported by impressive photos) that defy
your own experience can indicate potential computer
editing. Perfect margins, shading, alveolar bone
regrowth and other signs of perfection should raise
questions. Whether it is seen in a lecture on clinical
dentistry or in a magazine or journal touting whitening,
etc., one must be cautious. In the real world,
nothing is perfect. Any photo that is becomes suspect.
Computers are made to make straight lines and perfect
angles. This seldom occurs in real life and is
a dead giveaway for deception. The straight edges
and perfect angle of the virtual molar mesial occlusal
restoration in Figure 1f is a very good example.
Compare the irregular shape of real restorations in
Figure 3 with the straight, even artifacts in
Figure 1f. The four virtual restorations in Figure 2f
are another example. They are too perfectly rounded
and of similar size and shape — a rarity in real life.
Close examination of the margin of the virtual crown
in Figure 3f reveals a jagged border. This is an unrealistic
attempt to eliminate a straight line, and thus
detection that the image has been modified. 2,5,6
Many digitally enhanced DR restorations appear as
one solid color. Most natural restorations will show
various degrees of radiopaqueness (density), as the
restoration becomes thinner or thicker when placed
on or in a real tooth. Actual restorations are seldom
all one color or shade. Compare the real crown in
Figure 5 or the restorations in Figure 3 to the restoration
images of Figures 1f, 2f and 3f. There are
subtle differences in each real restoration’s peripheral
Look for “Frankenstein” images where, in many
photos, the head of a subject appears to be stitched
onto the body or a virtual tooth is inserted into a jaw.
Changes in shading, angles and seams can identify
this kind of manipulation. Relative uniform lighting
requires that shadows appear in the same direction
and on all areas of the photo. If they do not, then
editing should be suspect. Look at the reflections
of light on the skin of the patient in Figure 6 as
compared to virtual Figure 6f. In Figure 6f, there are
more highlights on the skin around the lips, indicating
that the shade of the entire photo was lightened
in order to make the teeth appear whiter. 1–8
Look for imperfections in geometry and whether
the vanishing point is “off.” Check if the quality of
the image is the same throughout the photo. If it is
not, then something may have been added. Look for
reoccurring patterns and objects, as well as discontinuities
in the background. A lazy image editor may
use standard shapes to fake restorations rather than
spend the time to draw each restoration individually.
Figure 2f shows virtual restorations of similar size
and perfect shape. These were digitally enhanced. 5,6
Often, enhancements to images can become apparent
if you use “false color image” editing. Radically
changing the contrast and brightness can also be telltale
signs. Using your computer to radically change
the colors (false coloring) of the suspected photo
will serve to identify otherwise subtle changes. This
process can be done in just a few seconds with most
photo editing software. 5–8
Look for artifacts of the editing process. These may
include tracks, brush marks, cavities and unnatural
compression. Rough texture transitions and uneven
pixilation (the small dots that make up the image)
across the image is strong evidence of editing. 6
Look at the reflections of light on the skin of the patient
in Figure 6 as compared to virtual Figure 6F. In Figure
6F, there are more highlights on the skin around the
lips, indicating that the shade of the entire photo was
lightened in order to make the teeth appear whiter.
Experienced image editors can detect metadata, short
digital fingerprints formed on every digital image. In
addition to storing information on the exact date of
creation and the modification of a file, metadata can
link the photo to the camera used, ownership (e.g.,
watermarking) and a variety of manipulations that
may have been used to modify the raw image. Unfortunately,
an image editor bent on deception can
remove this data and thus play an infinite cat-andmouse
game of detecting and hiding or scrubbing
evidence of image manipulation. Unless you wish
to spend considerable sums of time and money for
this service, this level of detective work is seldom
practical in dentistry. 5,6,8
Look at the size (megabytes) of the image file. Enhanced
images will have a considerably larger file
size than those that have no changes.
1. Calberson F, Hommez G, DeMoor R. Fraudulent use of digital radiographs.
Rev Belge Med Dent. 2005;60(1):58–67.
2. Guneri P, Akdeniz B. Fraudulent management of digital endodontic images.
Int Endod J. 2004;37(3):214–20.
3. Boscolo F, et al. Fraudulent use of radiographic images. J Forensic Odontostomatol.
4. Wadkins P. Digital radiographs. JADA. 2000;131(1):18,20.
5. Henshall J. Beware false reality. Photographer. 1998 Feb:28–30.
6. Casimiro S. Seeing is not believing. Popular Science. 2005 Oct:71–79.
7. Tsang A, Sweet D, Wood R. Potential for fraudulent use of digital radiography.
8. Gaylord C. Digital detectives discern Photoshop fakery. Christian Sci Monitor.
2007 Aug 29. Accessed 15 Dec 2007.
Reprinted with permission from the Journal of the Massachusetts Dental
Society, Vol. 57/No. 2, Summer 2008.
Because digital imaging has become so popular in dentistry,
images of photos and radiographs may be edited
to show different conditions than what is seen in reality.
Photos can be enhanced to show whiter and straighter
teeth, smoother skin or a well-blended margin on a
crown. Digital radiographs can be changed to show additional
pathology or treatment. There are numerous signs
of this manipulation, which an informed practitioner can
The authors wish to thank Andent Inc. for permission to
republish the photos in this article.
Dr. Ellis Neiburger is a general practitioner in Waukegan, Ill. Contact him at
847-244-0292 or firstname.lastname@example.org.
Yehonatan Frandzel is a forensic photography consultant based in Haifa, Israel.
Detecting Computer-Enhanced Dentistry51
Periodontal Photo Essay:
Is Closed-Flap Crown Lengthening
a Biologically Sound Procedure?
– ARTICLE and CLINICAL PHOTOS by Daniel J. Melker, DDS
The objective of this article is to discuss the biological aspects of bone and the changes that occur when it is infringed
upon either through disease or during the correction of certain periodontal conditions. It will discuss the correction of
osseous defects and why these procedures are necessary to create a long-term stable environment. When a comparison
is made between certain periodontal problems stemming from either biologic width invasion or periodontal disease
with closed-flap crown lengthening, similarities suggest that closed-flap crown lengthening is an unsound biologic
Periodontal Photo Essay53
Figure 1: In order to change the length of the clinical crowns for
a new restorative commitment, crown lengthening was advised.
When doing closed-flap crown lengthening, marks are made on
the laser tip to determine the amount of bone that needs to be
removed to create space for a new crown. Soft tissue can also
be removed when necessary. The major problem with such a procedure
is the inability to remove the troughs created by the vertical
removal of bone.
Figure 2: The restorative doctor and periodontist discussed
the case and determined that 1 mm of length would be needed
on the incisal edges. An appropriate formula was used for the
surgical procedure: biologic width, approximately 3 mm; clinical
crown length, 10 mm; added porcelain, 1 mm. The total length
needed from the existing incisal edge to the bone = 13 mm.
Note: Six weeks postoperatively, it will be determined if touchup
surgery will be necessary to correct any biologic changes.
Figure 3: During crown lengthening, troughs in the bone occur that
are similar to the periodontal vertical defects caused by endotoxins
released by bacteria. Notice the significant defect caused between
tooth #7 and #8; this is unavoidable.
Figure 4 Figure 5
Figure 4: A probe reveals the trough created in the bone due to
crown lengthening. The probe shows the vertical defect involving
line angles caused by the crown lengthening. The thicker the bone,
which is common in the interproximal, the greater the resulting defect.
Herein lies the problem with closed-flap crown lengthening:
Without the ability to remove the troughs created by lengthening
the teeth, serious long-term consequences can occur due to the
lack of uniformity between bone and soft tissue. It is critical for
bone to mimic soft tissue when contouring. The surgeon must
create a parabolic architecture. Note: Horizontal access and
visibility are necessary to remove the troughing caused by
Figure 5: Crown lengthening is completed on tooth #7 and #8.
Figure 6: Notice how the bone and soft tissue mimic each other.
The existing length of tooth #8 and #9 is now 13 mm from the bone
to the incisal edge. This allows for 3 mm of biologic width and
10 mm for the clinical crown, with the new crown adding 1 mm to
the incisal edge.
Periodontal Photo Essay55
Figure 7 Figure 8
Figure 7: The tissue is sutured into place using a 5-0 chromic gut.
Referring back to the original discussion on biologic width and
clinical crown length, the tissue is placed where the remaining tooth
structure is 10 mm. Notice there is an abundance of connective
tissue remaining. Without the ability to remove the troughing created
by the vertical removal of bone, the author finds closed-flap crown
lengthening to be biologically unsound. Horizontal access and
visibility are needed to create a sound biologic surgical procedure.
Figure 8: Day of impression. Notice the tissue is slightly red. Due to
her teaching schedule, the patient could not accommodate normal
postoperative appointments. (The author and case surgeon would
have preferred to see her several weeks before her impressions
to reduce any inflammation, as this is the doctor’s responsibility.
Subgingival chlorhexidine would be used to reduce minor inflammation.)
Figure 9: Final restorations with mild gingival irritation. Over time,
the author expects the tissue to improve, although reducing inflammation
prior to impression taking is the preferred method.
In this case, you will notice that the defect, which is
caused by biologic width invasion, mimics the defect
caused by closed-flap crown lengthening in the first
case. Both are biologically unsound.
Figure 1: Below tooth #5, the existing crown is violating the biologic
Figure 2: Reflection of a flap exposes a created defect on the
buccal of tooth #5, where biologic width invasion has occurred. To
correct the defect, horizontal removal of bone is necessary, as well
as the creation of bone architecture that mimics the soft tissue.
Figure 3: This shows the ideal osseous and soft tissue architecture
after proper bone contouring to remove the troughs. The crown is
violating the biologic width. This crown will be removed and a core
and a provisional will be placed.
Periodontal Photo Essay57
Figure 1: Crown lengthening is necessary to create a space for
the biologic width. The author believes that visibility is critical for
properly treating bone. A flap is required to see the underlying
structures for crown lengthening.
Figure 2: Regardless of the instrument — bur or laser — used when
crown lengthening is performed, bone is removed. Unless the tip
of the bur or laser is exactly the same dimensions as the bone to
be removed, a trough will be created when there is a greater thickness
of bone than tip diameter. This is a biologically unsound result.
The bur is left in place to show the crater that is created as the
bone is removed.
Figure 3: Using the bur or laser horizontally allows the crater to be
removed and an ideal osseous architecture to be created. Notice
that the bone and soft tissue mimic each other.
Figure 1: The existing crown on tooth #28 violates the biologic
width. There are periodontists who say that if the biologic width is
invaded, the bone will remodel to accommodate the infringement
on this area. In 35 years of treating biologic width invasion, the
author has consistently seen osseous defects associated with such
violations. No remodeling is noted.
Figure 2: Upon reflection of the tissue, a cratered defect is noted,
presumably associated with the biologic width invasion. This type
of defect must be removed to create an environment for the bone
and soft tissue to closely adapt for minimal probing depth.
Figure 3: The defect is removed and the osseous support will now
conform to the parabolic architecture of the soft tissue as it heals.
Thus, the bone mimics the soft tissue and minimal pocket depth
will be present upon complete healing.
Periodontal Photo Essay59
Figure 1 Figure 2
Figure 1: With the tissue reflected, the ravages of periodontal
disease on the bone can be seen clearly. A reverse architecture
is visible. This means that rather than the bone conforming to
the contours of the tissue, it is irregularly shaped, thus causing a
discrepancy between the soft tissue and the bone, resulting in a
Figure 2: After osseous contouring to remove the pocket in the
bone, the present configuration will mimic the soft tissue upon
healing. A minimal probing depth will remain, allowing for better
Without the ability to remove the troughing created by the vertical removal of bone, closed-flap crown lengthening is
biologically unsound. Horizontal access and visibility are needed to create a sound biologic surgical procedure. CM
Dr. Daniel Melker is in private practice in Clearwater, Fla., and lectures nationwide. Contact him at 727-725-0100.
Patient Product Review
In my experience, men love toothpicks. It has also been my experience that men don’t floss. Traditionally, dental
professionals have been conditioned to persuade male patients to routinely floss. (Ask your hygienist how this educational
approach is going, if you aren’t sure.)
I instead prefer to give men a tool they will use regularly, even if it isn’t as effective as flossing: the toothpick. Wooden
toothpicks, which are freely available in all restaurants, have some limitations that make them a less than ideal choice
for routine use. However, Opalpix toothpicks by Ultradent are flat and tapered to allow good interproximal access with
minimal trauma to the papilla. I’ve seen patients do a pretty good job of getting them under fixed bridgework, as well.
It’s a great option for the floss-phobic men (read: all men) who come to your practice. CM
Opalpix is a trademark of Ultradent Products Inc. To purchase this product, contact your local dental dealer or visit https://store.ultradent.com.
Dr. DiTolla's Patient Product Review63
The Chairside® PHOT Hunt
How many differences between
the two pictures can you find?
Circle the differences on the version
labeled NEW below. Then,
write down how many differences
you found, tear out this whole
page and send it to:
ATTN: Chairside magazine
4141 MacArthur Blvd.
Newport Beach, CA 92660
Or scan your entry and e-mail it to
One entry per office. Participation
grants Chairside magazine permission
to print your name in a future
issue or on its website.
The winner of the Vol. 6, Issue 1,
Chairside Photo Hunt Contest will
receive $500 in Glidewell credit
or a $500 credit toward his or
her account. The second- and
third-place winners will each receive
$100 in Glidewell credit or a
$100 credit toward their accounts.
Entries must be received by
March 31, 2011. The winners will
be announced in the spring issue
of Chairside magazine.
City/State of Practice
“With the current price of gold,
dentists have begun mining.”
Jeri Coffey, DDS
1st place winner of $500 lab credit
“No, he doesn’t need crown
lengthening. It’s only 12 mm
Stephen L. Kirkpatrick, DDS, PLLC
2nd place winner of $100 lab credit
“That’s not the nerve …
It’s a Chilean miner!”
Gregory L. Jovanelly, DMD
3rd place winner of $100 lab credit
“These OSHA requirements are getting more strict every day!”
Ernest Johnson, DDS
“No, but I did stay at a Holiday Inn Express last night.”
James Tagliarini, DMD
The Chairside ®
Caption Contest Winners!
Congratulations to Drs. Jeri Coffey, Stephen Kirkpatrick and Gregory Jovanelly, winners of the Vol. 5, Issue 4, Chairside Caption Contest.
The winning captions were chosen from hundreds of entries e-mailed and submitted online to Chairside magazine when readers were
asked to caption the above photo. Entries were judged on humor and ingenuity.