The Modified Grassline Technique: A Case Report - DentalCEToday

Continuing Education
Course Number: 147.1
The Modified Grassline
Technique:
A Case Report
Authored by Arthur R. Volker, DDS, MSEd, and Gerald S. Wank, DDS
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Continuing Education
The Modified Grassline Technique:
A Case Report
Effective Date: 03/1/2012 Expiration Date: 03/1/2015
LEARNING OBJECTIVES
After participating in this CE activity, the individual will learn:
• A technique for the conservative orthodontic movement
of periodontally involved teeth.
• Factors to be considered before orthodontic treatment of
compromised teeth.
ABOUT THE AUTHORS
Dr. Volker graduated from the Columbia
University School of Dental and Oral
Surgery. He received a Fellowship from
the AGD and is the chairman of the New
Dentist Committee and a member of the
Continuing Education Com mittee for the
New York State AGD. He is a clinical attending at the Coler-
Goldwater Specialty Hospital and Nursing Facility in
Roosevelt Island, NY, and is in private practice in Queens,
NY. He can be reached via e-mail at volkerdds@gmail.com.
Disclosure: Dr. Volker reports no disclosures.
Dr. Wank is a clinical professor of
periodontics and implantology at the New
York Uni versity College of Dentistry. He has
received Fellowships in the American
College of Dentists, International College
of Dentists, American Academy of Oral
Medicine, New York Academy of Dentistry, American Public
Health Association, and AGD. He is a consultant in
periodontics at the New York Veteran’s Hos pital, as well as a
consultant in perio-ortho-prosthodontics at Coler-Goldwater
Specialty Hospital and Nursing Facility in Roosevelt Island, NY.
Dr. Wank is an international lecturer and has published in
many peer-reviewed journals. He can be reached via e-mail at
gwank@aol.com.
Disclosure: Dr. Wank reports no disclosures.
INTRODUCTION
Grassline threads were used for the noninvasive
intermittent movement of malposed teeth from the 1940s to
the 1980s. 1 Derived from the ramie plant, grassline is a
heavily twisted fiber that shrinks when exposed to fluids.
Un fortunately, grassline is no longer commercially
available. Recently, Lohmiller 2 de mon strated a modified
version of the technique whereby heavily twisted 100%
cotton crochet thread of varying sizes and composite
“holds,” which function similarly to orthodontic brackets, can
be used as a suitable substitute.
Once thought to be a contraindication to orthodontic
therapy, periodontal disease is no longer a barrier to
comprehensive treatment, although special considerations
must be employed. 3,4 The determination of primary versus
secondary trauma to the patient’s dentition must also be
addressed. 5 Primary trauma results in periodontal damage
from excessive occlusal loading on a healthy peridontium,
such as a “high” restoration left unresolved. Secondary
occlusal trauma occurs when nonexcessive masticatory
forces result in periodontally-compromised teeth being put
into occlusal over-function. Since these teeth no longer
possess the alveolar structural support to withstand what
was once normal loading, routine function becomes a
damaging force. This loading can come from the opposing
dentition as well as soft tissue, particularly the habitual
thrusting of the tongue on the lingual surfaces of anterior
teeth. Pathologic movements of these teeth can easily
occur. 6,7 As such, retention management after the
completion of treatment is of paramount importance. 8
The inherent advantage of grassline and the modified
cotton thread technique is that they deliver force
intermittently. When exposed to oral fluids, there is a finite
shrinkage to the cotton threads, approximately 3% to 10%
depending on its thickness and processing treatment. 9 As
a result, movement of the treated teeth occurs
incrementally, as these teeth are held at their new position
until the next tie sequence is to be performed. This
utilization of an intermittent force as opposed to a
continuous force, such as that found in elastics or springs,
provides advantages for the periodontally in volved
dentition. It has been shown that the use of intermittent
orthodontic forces resulted in less root resorption than oc -
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curred with continuous forces
in periodontally compromised
teeth. 10-12
The following case report
discusses the application of a
modified grassline technique to
the periodontally compromised
patient.
a
Continuing Education
The Modified Grassline Technique: A Case Report
b
CASE REPORT
A 55-year-old white female with no significant contributory
medical history presented with a chief complaint of, “I have
big spaces between my lower front teeth” (Figures 1a to 3).
The patient reported that she had orthodontic treatment as
an adolescent and ad mitted to habitual tongue thrusting.
Ad di tionally, she claimed to be a nocturnal bruxer and had
worn a maxillary nightguard intermittently for the past
20 years.
An orthodontic examination revealed a bilateral Class II,
division II occlusal relationship, with a 40% vertical overbite, 2
mm horizontal overjet, and no maxillary midline discrepancy.
Incisal wear was noted on the lower anterior incisors
and wear facets were noted on posterior teeth. Additionally,
large fractured buccal portions of teeth Nos. 3, 19, and 30
were observed. A periodontal assessment revealed clinical
plaque and calculus, as well as 2 to 3 mm pocketing of
anterior teeth with bleeding upon probing. Radiographs
revealed 40% to 60% bone loss of mandibular anterior
teeth with a widened periodontal ligament interproximally
(funneling) (Figure 4).
The patient was made fully aware that realignment of
the mandibular an terior teeth without subsequent treatment
of the maxillary teeth would result in an increased overjet.
The pa tient was unwilling to undergo comprehensive
orthodontic treatment which would involve possible
extraoral anchorage and/or bilateral bicuspid extraction. In
addition, the patient was made aware that further labial
tipping of the mandibular anterior teeth from tongue
thrusting would lead to further periodontal compromise,
including an increased loss of keratinized gingival
attachment as well as buccal bone.
The proposed course of orthodontic treatment was to
use the crochet thread to bring the mandibular anterior
Figures 1a and 1b. Initial view of patient’s malalignment.
Figure 2.
Initial frontal view of
patient’s mandibular
malalignment.
Figure 3.
Initial occlusal view.
Figure 4.
Initial periapical
presentation.
Note 40% to 50%
bone loss of the
mandibular
incisors as well
as widening of
the periodontal
ligament
(funneling).
teeth into alignment. Retention would then be provided by a
fixed lingual splint to prevent orthodontic relapse and to
negate the effects of secondary occlusal trauma and
tongue thrusting.
Full-mouth scaling and root planing was performed to
2

maximize periodontal health prior to tooth movement.
Temporary microhybrid composite (Herculite Ultra [Kerr])
occlusal “buildups” on teeth Nos. 3, 19, and 30 were
completed to aid in bite stabilization. Full-coverage
restorations were planned for these teeth following or thodontic
treatment.
Using a total-etch bonding protocol, microhybrid
composite “holds” were appropriately positioned on teeth
Nos. 22 to 27. The holds function similarly to conventional
orthodontic brackets in that they help to direct forces
resulting from the contraction of the crochet thread as well
as prevent slippage of the thread gingivally or incisally.
Continuing Education
The Modified Grassline Technique: A Case Report
Essentially, a ball of un cured composite was placed on the
facial surface of an involved tooth. A bracket height gauge
was used to make a properly positioned indentation in the
composite and held in position against the tooth during
curing. Rough edges and excess composite impeding
placement of the thread were subsequently removed. A
typo dont representation of the technique is shown in
Figures 5a to 5d.
The 100% cotton heavily twisted crochet thread (Mez)
was tied around the indicated teeth in the manner
prescribed by Wank 1 (Figures 6a to 6j). The initial ties were
completed with size 20 thread, as the larger the thread size,
a b c d
Figures 5a to 5d. Demonstration on typodont for placement of composite “holds.”
a b c d
e
f
g
h
i
j
Figures 6a to 6j.
Tie sequence for thread placement.
3

Continuing Education
The Modified Grassline Technique: A Case Report
the greater the shrinkage, and subsequently, the greater
the amount of tooth movement. Every 7 to 10 days, the ties
were replaced, and the positioning of ties depended on the
movement needed (Figures 7 and 8). As interdental
spacing decreased and teeth moved into a more optimal
position, smaller threads were tied as less movement was
needed. Thread placement was also managed to allow for
ideal interproximal closure (Figures 9 and 10). After 12
weeks of treatment, which consisted of 10 thread changes,
the desired positioning was obtained (Figure 11).
A 0.010” x 0.020” stainless steel annealed ribbon-wire
was bonded utilizing a total-etch technique and microhybrid
composite (Herculite Ultra) as a fixed lingual retainer from
teeth Nos. 22 to 27 (Figure 12). Periodic observation of
these teeth is planned to determine if functional or
parafunctional forces cause any movement from the final
position. Should this occur, circumferential splinting would
be provided. 13 A postoperative radiograph reveals
resolution of funneling of the periodontal ligament and
evidence of bone apposition (Figure 13).
Figure 10. Occlusal
view of treatment
progression after
10 weeks. Note the
thread positioning
to allow for interproximal
space
closure.
Figure 11.
Final frontal view
after 12 weeks of
treatment, which
consisted of 10
thread changes.
Figure 12.
Final occlusal view
after placement of
fixed lingual
retainer.
Figure 7.
Midtreatment ties.
Note how the
composite “holds”
maintain the
position of the
threads.
Figure 8.
Progression of
tooth movement
after 10 weeks. As
interdental space
was closed, smaller
threads were
placed.
Figure 13.
Periapical radiograph
demonstrating
evidence of bone
apposition.
Figure 9.
Occlusal view
of treatment
progression after
6 weeks.
CONCLUSION
Several methods of applying interim forces are available for
orthodontic therapy. Examples include clear aligners (eg,
Invisalign) and modified removable elastic acrylic combos
4

(pseudo intermittent forces).
However, they generally have a
higher laboratory cost associated
with their use compared to the
thread technique described here.
Other advantages, as well as
disadvantages of the technique,
are described in the Table.
The use of the modified
grassline technique can be a
safe and effective treatment
modality, particularly for those
patients who are compromised periodontally.
Acknowledgement
The authors would like to express their gratitude to Mr. Frank
Pavel, assistant director of the Medical Library at Coler-
Goldwater Specialty Hospital and Nursing Home, and Dr.
Fred Cook, professor, School of Polymer, Textile & Fiber
Engineering at the Georgia In stitute of Technology, for their
help in the preparation of this article.
REFERENCES
1. Wank GS. The use of grassline ligature in periodontal
therapy. Dent Clin North Am. 1972;16:473-486.
2. Lohmiller RM. Modified grassline technique for
orthodontic space closure. Eur J Esthet Dent.
2006;1:30-51.
3. Re S, Corrente G, Abundo R, et al. Orthodontic
treatment in periodontally compromised patients:
12-year report. Int J Periodontics Restorative Dent.
2000;20:31-39.
4. Feng X, Oba T, Oba Y, et al. An interdisciplinary
approach for improved functional and esthetic results
in a periodontally compromised adult patient. Angle
Orthod. 2005;75:1061-1070.
5. Wank GS, Kroll YJ. Occlusal trauma. An evaluation
of its relationship to periodontal prostheses. Dent Clin
North Am. 1981;25:511-532.
Continuing Education
The Modified Grassline Technique: A Case Report
Table. Advantages and Disadvantages of the Modified Grassline Technique
ADVANTAGES
Intermittent forces
Cost
Aesthetically more pleasing than
metal brackets
Decreased trauma to oral tissues
compared to brackets
DISADVANTAGES
Technique sensitive
Ties must be changed every
7 to 10 days
Thread may untie or tear
Not as effective in patients with
healthy peridontium
6. Geiger AM. Malocclusion as an etiologic factor in
periodontal disease: a retrospective essay. Am J
Orthod Dentofacial Orthop. 2001;120:112-115.
7. Towfighi PP, Brunsvold MA, Storey AT, et al.
Pathologic migration of anterior teeth in patients with
moderate to severe periodontitis. J Periodontol.
1997;68:967-972.
8. Greenstein G, Cavallaro J, Scharf D, et al. Differential
diagnosis and management of flared maxillary
anterior teeth. J Am Dent Assoc. 2008;139:715-723.
9. Heap SA, Greenwood PF, Leah RD, et al. Prediction
of finished weight and shrinkage of cotton knits—The
Starfish Project: Part I: Introduction and general
overview. Textile Research Journal. 1983;53:109-119.
10. Ballard DJ, Jones AS, Petocz P, et al. Physical
properties of root cementum: part 11. Continuous vs
intermittent controlled orthodontic forces on root
resorption. A microcomputed-tomography study.
Am J Orthod Dentofacial Orthop. 2009;136:8.e1-8.
11. Konoo T, Kim YJ, Gu GM, et al. Intermittent force in
orthodontic tooth movement. J Dent Res.
2001;80:457-460.
12. Hayashi H, Konoo T, Yamaguchi K. Intermittent 8-hour
activation in orthodontic molar movement. Am J
Orthod Dentofacial Orthop. 2004;125:302-309.
13. Wank GS. Modified circumferential splint for periodontally
involved teeth. Dent Surv. 1976;52:40-42,49-51.
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Continuing Education
The Modified Grassline Technique: A Case Report
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POST EXAMINATION QUESTIONS
1. Advantages of the modified grassline technique
include:
a. Intermittent forces.
b. Cost.
c. Aesthetically more pleasing than metal brackets.
d. All of the above.
2. What are common sequelae of pathologic labial
tipping of the mandibular anterior teeth?
a. Loss of gingival attachment.
b. Loss of buccal bone.
c. Loss of lingual bone.
d. Both a and b.
3. How often does the grassline tie get replaced?
a. Every 2 months.
b. Every month.
c. Every 7 to 10 days.
d. Every other day.
4. Secondary occlusal trauma results from:
a. Nonexcessive masticatory forces resulting in
periodontally compromised teeth being placed into
occlusal over function.
b. Nonexcessive masticatory forces resulting in
nonperiodontally compromised teeth being put into
occlusal over function.
c. Excessive occlusal loading on a healthy peridontium.
d. Nonexcessive occlusal loading on a healthy
peridontium.
5. Which orthodontic modalities employ an intermittent
force?
a. Spring.
b. Elastics.
c. Grassline.
d. Both a and b.
6. What is an inherent advantage of using intermittent
orthodontic forces over the use of continuous
orthodontic forces?
a. Reduced occlusal loading on opposing dentition.
b. Increased likelihood of root resorption.
c. Reduced likelihood of root resorption.
d. Reduced total treatment time.
7. Why are composite “holds” placed on the teeth
during treatment?
a. To aid in direction of forces.
b. To function as a torque multiplier.
c. To prevent incisal or gingival slippage of the thread
during movement.
d. Both a and c.
8. Using a larger cotton thread size will result in:
a. Decreased movement.
b. Increased movement.
c. Increased fracture resistance of composite “holds.”
d. Both a and c.
6

Continuing Education
The Modified Grassline Technique: A Case Report
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