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Creating Surgical Guides Using CBCT and Intraoral Scanning
“missing” teeth, and had also lost a number of teeth after
failed endodontic procedures. The patient was first seen
by the Department of Oral and Maxillofacial Surgery of
Virginia Commonwealth University’s School of Dentistry,
with a stated desire for using dental implants to restore
the missing teeth. The patient was referred to my private
practice for an evaluation of his restorative needs.
Treatment Plan
After a discussion of the alternatives, benefits, and complications
of treatment options, the patient stated that
he wished to receive implant restorations. Following a
discussion of financial considerations, it was agreed that
the treatment plan would be divided into several phases.
Phase one would be to place two implant fixtures in the
area of tooth #29 and tooth #30. It was agreed that a custom
surgical guide would be created using CBCT and digital
scanning technology, for the ultimate purpose of facilitating
guided placement of the dental implants.
Scan Procedure
A full-arch optical scan of both maxillary and mandibular
arches with a centric record of the teeth in maximum
intercuspation was taken using the iTero intraoral scanning
unit. The resultant generic STL data files, the standard
CAD/CAM file format, were exported directly from this
user’s “MyAligntech” account. A CBCT scan was taken with
a NewTom CBCT scanner (ImageWorks; Elmsford, N.Y.) and
the resultant DICOM data files exported to the In2Guide
(Cybermed; Irvine, Calif.) software. The DICOM and STL
files types were then merged via the In2Guide software to
produce a 3-D rendering.
Virtual Planning
Using the principles of “crown down” planning, a virtual waxup
added the crown morphology to represent a mandibular
right second bicuspid (tooth #29) and a mandibular right
first molar (tooth #30) (Fig. 2). Using the implant placement
planning features of the In2Guide software, an optimized
position for each of the implant fixtures was developed.
This case demonstrates the value of virtual planning, as
there were several anatomical and dental issues requiring
close attention to fixture placement detail. The mandibular
second molar is mesial-tipped, presenting a clearance
and path of insertion issue for the prosthetic restoration
of the implant fixture. Further, the hard tissue anatomy
exhibits limited freedom of placement, given the position
of the inferior alveolar canal, mental foramen, and lingual
Figure 2: In2Guide planning software with virtual wax-up of tooth #29 and
#30
mylohyoid concavity. With the virtual planning complete,
the completed implant fixture placement was submitted for
CAD processing.
Surgical guide
In a 100 percent digital environment, a model-less printed
surgical guide was produced by the Cybermed In2Guide
manufacturing process. The surgical guide was delivered in
a sealed package for patient try-in. Planned visual cutouts
allowed verification of proper seating of the surgical guide
(Fig. 3). Prior to the surgical appointment, the surgical guide
was trial fitted to the mandibular dentition (Fig. 4), and
optimal fit confirmed (Fig. 5).
Surgical Procedure
After a review of the patient’s health history, including
basic vital signs such as blood pressure and pulse, informed
consent was received. The patient was given two 1.7 ml
carpules of Lidocaine Hydrochloride 2% with 1:100,000
Epinephrine. Upon profound local anesthesia, with the
surgical guide in place, a single disposable tissue punch
(Fig. 6) was used to remove a precise cylinder of tissue to
access the mandibular ridge of bone at the planned implant
surgical site. NobelGuide drill guides and guided drills
(Nobel Biocare; Yorba Linda, Calif.) were used to perform
the surgical procedure. The drill series consisted of an
initial “flare” drill (Guided Start Drill) (Fig. 7), a 2 mm depth
drill (Guided 2.0 Twist Drill) used with a precise drill guide
(Fig. 8), and sequential full-depth drills (Guided Tapered
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