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L E T T E R S
increase the ferrule length will
reduce the root length invested
in bone and possibly make the
crown to root ratio unfavorable.”
In my opinion, this is not always true when the OFE, with
or without the surgery, is carried out. The OFE followed by
surgical crown lengthening produces a more stable and favorable crown-root ratio.1 Surgical
crown-lengthening alone would
produce an unstable and unesthetic crown-root ratio. This is
well explained through a
schematic diagram by
Shillinburg and colleagues.1
Associated with periodontal
surgery, it also exposes subgingival lesions and preserves a
harmonious gingivo-osseous
morphology.
The rationale behind the
OFE is that, by stretching the
gingival and periodontal ligament fibers during OFE, tension is imparted to the entire
alveolar socket, stimulating osseous apposition at the alveolar
crest.2,3 This increases the width
of the attached gingiva, and the
mucogingival junction remains
stable when the gingival margin
migrates coronally.2-4
Forced eruption has advantages over surgical crown
lengthening, which causes negative change in the length of the
clinical crowns of both the tooth
and the neighboring teeth, produces poor esthetics, widens
embrasures and is less conservative, considering the sacrifice
of supporting bone of adjacent
teeth.5
The authors also mentioned
regarding the OFE that
“[o]rthodontic procedures add to
the cost of restoring the tooth
and prolong treatment.” Generally, two anterior teeth and two
posterior teeth can be bonded
with orthodontic brackets for this
purpose. Removable appliances
or anchorage wires bonded to adjacent teeth can also be used to
achieve forced eruption.5 Whatever appliance is used, OFE can
be as rapid as 1 millimeter per
week without damage to the
periodontal ligaments; hence,
three to six weeks are sufficient
for almost any patient.5,6
Looking at the cost-to-benefit
ratio, I think the treatment involving OFE is advantageous,
Forced eruption has
advantages over surgical
crown lengthening, which
causes negative change in
the length of the clinical
crowns of both the tooth
and the neighboring teeth.
and one should not overlook
considering this option as one
of the principal entities in treatment planning.
Pravinkumar G. Patil,
MDS
Assistant Professor
Department of Prosthodontics
Government Dental College
and Hospital
Nagpur (Maharashtra)
India
1. Shillinberg HT, Hobo S, Whitsett LD,
Jakobi R, Brackett SE. Fundamentals of
Fixed Prosthodontics. 3rd ed. Chicago:
Quintessence; 1997:191-193.
2. Schincaglia GP, Nowzari H. Surgical
treatment planning for the single unit implant in aesthetic areas. Periodontol 2000
2001;27:162-182.
3. Chambrone L, Chambrone LA. Forced orthodontic eruption of fractured teeth before
implant placement: case report. J Can Dent
Assoc 2005;71(4):257-261.
4. Salama H, Salama M. The role of orthodontic extrusive remodeling in the enhancement of soft and hard tissue profiles prior to
implant placement: a systematic approach to
the management of extraction site defects. Int
J Periodontics Restorative Dent 1993;13(4):
312-333.
5. Jafarzadeh H, Talati A, Basafa M,
Noorollahian S. Forced eruption of adjoining
maxillary premolars using a removable orthodontic appliance: a case report. J Oral Sci
2007;49:75-78.
JADA 141(10)
6. Proffit WR, Fields HW Jr, Ackerman JL,
Bailey LJ, Camilla Tulloch JF. Contemporary
Orthodontics. 3rd ed. St. Louis: Mosby; 2000:
627-632.
MORE ABOUT CROWN
LENGTHENING
I am writing regarding Dr.
Timothy Hempton and Dr.
John Dominici’s June JADA
article, “Contemporary CrownLengthening Therapy: A Review”
(JADA 2010;141[6]:647-655).
Regardless of the need for
crown lengthening, the type of
restoration proposed is not as
advantageous as short chamfer
long bevel. A chamfer bevel
preparation removes less axial
tooth structure than long shoulders, resulting in stronger tooth
integrity. The advantages of a
long bevel versus shoulder are
less chance of creating a ledge
from short/long gingival restoration margins, resulting in easier
patient hygiene; allows high
noble metal to be burnished, resulting in a better restoration
profile and sealing against bacteria, therefore leading to less
inflammation. In addition, long
bevels (diagonal cut of the cylinder) allow for longer margins on
harder tooth structure enamel/
cementum exposed to oral cavities than dentin in case of any
gaps or uncovered margins of
restored teeth.
The article suggests that for
a Class V restoration, “the dentist can perform the needed osseous removal solely on the facial or lingual aspect.” According to Lindhe and colleagues,1
the soft tissue cannot follow
abrupt and steep changes in the
osseous profile: “The process of
osseous resection requires that
bone be removed from the adjacent teeth to create a gradual
rise and fall in the profile of the
osseous crest.” The restoration
would invade the zone of superhttp://jada.ada.org
Copyright © 2010 American Dental Association. All rights reserved. Reprinted by permission.
October 2010
1183
L E T T E R S
crestal connective tissue and, at
the very least, create a chronic
marginal gingivitis, if not a
periodontal pocket. This inflammation also can have a negative
esthetic effect.
However, the most important
point is that dentists are morally and ethically bound to the
principle of “first, do no harm.”
Any restoration that causes inflammation in the mouth, in
turn causing the release of
chemical mediators, has a deleterious systemic effect more far
reaching than fixing the tooth.
The media and organized
dentistry have been educating
the public on the significance of
inflammation and its systemic
effect on the overall health and
urging the public to seek dental
treatment. Evidence-based dentistry (EBD) allows uniformity
in practice based on science.
EBD creates credibility and
trust between the public and the
profession. Is it right to restore
a tooth and cause gingival inflammation which in turn may
cause heart or lung problems?
Dentistry is not transitioning
fast enough in incorporating
EBD knowledge into practice.
The dental schools taught us
to treat the patient’s overall
health and not just the tooth.
Crown lengthening as defined
by Current Dental Terminology
Code D42492 does not reflect
biological width. Most insurance
companies only address the
amount of tooth structure exposed above gingival level for
the purpose of retention of restoration and not biological width.
Myopic vision created by insurance coverage of the procedure
could convert a dentist approach
to a provider approach. Is our
profession about becoming a
provider? The systemic effect of
biological width is far more im1184
JADA 141(10)
http://jada.ada.org
portant or equally as important
as retaining a tooth, and it is
EBD.
Fereydoun Haghkerdar,
DMD
Wellesley, Mass.
1. Lindhe J, Karring T, Lang NP, eds.
Clinical Periodontology and Implant
Dentistry. 4th ed. Oxford, England: Blackwell;
2003:624.
2. American Dental Association. CDT 20092010: Current Dental Terminology. 7th ed.
Chicago: American Dental Association; 2008.
Any restoration that causes
inflammation in the mouth,
in turn causing the release
of chemical mediators, has
a deleterious systemic
effect more far reaching
than fixing the tooth.
Authors’ response: We appreciate the thoughtful comments from Dr. Haghkerdar
and Dr. Patil. Our article was
not a discussion on the design of
crown margin preparation, but
rather where the crown margin
should be placed relative to the
periodontal attachment apparatus. We discussed avoidance of
invasion of the 2-millimeter dentogingival junction and included
Ingber and colleagues’1 recommended placement of the crown
margin at least 3 mm coronal to
the osseous crest. Moreover, Colt2
described this 3-mm distance as
the physiological restorative dimension allowing for periodontal
health in the presence of restorative treatment.
The type of crown margin selected by the dentist may vary
depending on the parameters of
the clinical situation. Our intention was to state that, whichever margin design is utilized,
placing any restorative material
adjacent to that margin within
2 mm of the supporting bone
may result in bone loss. Surgery
also may result in bone loss,
however; the difference with
surgical intervention is that the
bone removal is controlled.
Concerning exposure of Class
V lesions, the article was focused on the concept that if the
caries did not extend to the
proximal surfaces of the tooth,
the dentist could avoid reshaping the interproximal bone adjacent to the affected tooth. As Dr.
Haghkerdar pointed out, excessive facial or lingual ostectomy
on one tooth may result in
abrupt and steep changes in the
osseous profile relative to the
adjacent teeth. If such dramatic
bone removal were needed to
expose Class V caries on a single
tooth, extraction may be a more
compelling treatment option.
We agree with the concerns
expressed about implementation of evidence-based dentistry
into clinical practice. Periodontal inflammation and its
systemic effect on the overall
health was also mentioned.
There is evidence demonstrating a link between periodontal
disease and systemic health.3
The strength of that link, however, is still under investigation. As of yet, we have not seen
any research clearly indicating
gingival inflammation caused by
a subgingival restoration can increase the risk of heart disease
or worsen a diabetic condition.
Regarding insurance codes,
we agree that mention of the
“biological width” in the CDT
code description would be intellectually gratifying. Delta
Dental of Virginia did review
the concept of violation of the
biological width by restorative
therapy in a March 2010 insurance bulletin.4 The company
noted that code D4249, Clinical
crown lengthening–Hard tissue,
October 2010
Copyright © 2010 American Dental Association. All rights reserved. Reprinted by permission.
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