anterior open bite as a complication of the treatment of bruxism with

CLINICAL DENTISTRY AND RESEARCH 2011; 35(3): 53-58
ANTERIOR OPEN BITE AS A COMPLICATION OF THE TREATMENT
OF BRUXISM WITH ANTERIOR BITE PLANE: A CASE REPORT
Gülay Uzun, DDS, PhD
ABSTRACT
Professor, School of Dental Technology,
Hacettepe University,
Bruxism is one of the major dental diseases indicating that up
Ankara, Turkey
to 20% of the population have signs of significant wear on their
Filiz Keyf, DDS, PhD
Professor, Department of Prosthodontics,
Faculty of Dentistry, Hacettepe University,
Ankara, Turkey
teeth. The etiology and pathophysiology of this disorder are
still unclear. Anterior bite plane has been shown to be beneficial
in the management of the signs and symptoms associated
with bruxism, including nocturnal headaches in certain patient
populations. The clinical report of a 55-year-old female patient
who has been using an anterior bite plane for 2 years for the
treatment of bruxism describes how spontaneously anterior
open bite occured in this patient after the application of
anterior bite plane for the treatment of bruxism.
Correspondence
Gülay Uzun, DDS, PhD
School of Dental Technology,
Hacettepe University,
06100, Sıhhiye, Ankara, Turkey
Phone: +90 312 3051587
Fax: +90 312 3102730
E-mail: vuzun@hacettepe.edu.tr
Key words: Bruxism, Open Bite, Splint
Submitted for Publication: 12.29.2010
Accepted for Publication : 02.17.2011
53
CLINICAL DENTISTRY AND RESEARCH
INTRODUCTION
Bruxism is a parafunctional activity observed both in
adolescent and adult populations. The mean prevalence is
about 20% and is decreasing with age. Women appear to
clench more frequently than men.1, 2
The term bruxism refers to nonfunctional grinding of
the lower teeth against the upper teeth. If uncontrolled,
it generally leads to severe abrasive wear of the occlusal
surfaces or hypermobility of the teeth and may also
contribute to adaptive changes in the temporomandibular
joints, resulting in flattening of the condyles and gradual loss
of convexity of the eminentiae. Symptoms of bruxism include
dull headaches, sore and tired facial muscles, earaches,
sensitive teeth, and locking, popping, and clicking of the jaw.
Bruxism is associated with muscle spasm, split teeth, and
fractured fillings. The cause of bruxism is not completely
clear.3-7 This can be accomplished in two ways: Directly by
equilibration, occlusal restorations, or orthodontics, and
indirectly by occlusal splints.3
The beneficial effect of acrylic occlusal splints or night
guards is the result of occlusal correction in the appliances
themselves and the stabilizing effect they have on the teeth.
The elimination of signs of bruxism will occur with virtually
any technique that eliminates occlusal interferences, either
on the teeth themselves or on an appliance that fits over
the teeth. A common fallacy regarding occlusal splints is
that the relief of symptoms is the result of the increased
vertical dimension.3,6,7
There are several different kinds of splints that can be used
for bruxism therapy. Some splints are worn on the upper
teeth, while others are worn on the lower teeth. There are
also partial coverage and full coverage splints. While partial
coverage splints are worn over only the back or front teeth,
splints that provide full coverage are worn over all of the
teeth. This allows the specialist who is overseeing the
splint therapy to have more control over the creation of the
new bite, and lessens the risk that the teeth or jaw could
shift over time. Finally, there are directive and permissive
splints. While directive splints hold the jaw in a fixed
position, permissive splints allow it to find its own position
and move more smoothly and naturally. Permissive splints
are more modern alternatives that many patients find less
restrictive and easier to wear on a daily basis. Permissive
splints are designed to unlock the occlusion to remove the
deviating tooth inclines from the contact. Any splint design
is permissive if it unlocks occlusal incline contacts and
provides a smooth gliding surface that permits uninhibited
54
muscle positioning of the mandible. Permissive splints can
be made for either anterior or posterior teeth, or for upper
or lower teeth.3-11
A properly made centric relation occlusal splint is a
permissive splint. If centric relation can clearly be verified,
on occlusal splint, then it can be fabricated with multiple,
equal-intensity occlusal contacts of the cusp tips on the
opposing arch against the occlusal surface of the splint.3
Directive splints are designed to position the mandible in a
specific relationship to the maxilla. The anterior bite plane
is a hard acrylic appliance worn over the maxillary teeth
providing contact with only the mandibular anterior teeth.
It is primarily intended to disengage the posterior teeth, and
thus eliminate their influence in the function or dysfunction
of the masticatory system. Anterior bite planes can be
fabricated either directly in the mouth or in directly on
mounted diagnostic casts. Although direct fabrication has
the advantage of requiring less time to make the appliances,
it is not an acceptable method if the appliance is to be
converted to a full occlusal splint. It is, however, a practical
procedure to use overnight as a muscle deprogrammer
or to determine whether condyle-disk alignment can be
maintained during function.3
This clinical report describes spontaneous anterior open
bite occurred in this patient after the application of the
anterior bite plane for the treatment of bruxism.
CASE REPORT
A 55-year-old retired female patient came to our clinic with
complaints of bruxism, and anterior open bite. Mandibular
movement was normal during opening (44 mm) and right
and left lateral excursions (8 mm). No pain was felt. The
occlusal examination disclosed a complete natural dentition.
Moderate tooth wear was apparent on the anterior teeth.
The other occlusal findings were within normal limits. There
were no other significant findings in either the history or
the clinical examination. Examination showed no pain
or tenderness in either joint. Observation and palpation
revealed normal movement of the condyle during opening.
The transcranial radiograph and panoramic radiograph
depicted the subarticular surfaces as normal. The patient
was treated with anterior splint for two years (Figures 1,
2 and 3). Her anterior teeth were not in contact position
and there was an anterior open bite when she was referred
to our dental clinic (Figures 4, 5 and 6). The patient was
suffering from the spacing between the anterior teeth.
There was a speech difficulty.
The Treatment of Bruxism
Figure 1. Anterior bite plane in occlusion
Figure 4. Anterior open bite
Figure 2. Anterior bite plane in the mouth
Figure 5. Open mouth position
Figure 3. Anterior bite plane
Figure 6. Front view of the patient
55
CLINICAL DENTISTRY AND RESEARCH
The impressions were made from maxillary and mandibular
arches, and casts were prepared and mounted in centric
relation. A vertical pin was set so that there would be
approximately 1mm of space between the teeth that
contact first. Acrylic resin was adapted to the palate and
maxillary occlusal surfaces and the articulator was closed
onto the vertical space established by the incisal pin. Then
the model was taken out and the resin was removed from the
maxillary cast and polished (Figure 7). Occlusal adjustment
was made in the mouth, and the following day the patient
was checked for the splint adaptation and evaluated so as
to see if any problems occured (Figures 8, 9). The patient
was recalled to the clinic one week after the review and was
checked for any complications. The recalls were scheduled
at 1 month, 3 months, 6 months after splint delivery.
Figure 7. Centric relation occlusal splint
DISCUSSION
Many types of occlusal splints have been advocated (Figures
10, 11). They may be full or partial occlusal coverage,
maxillary or mandibular, repositioning or stabilising, and
made from a variety of different materials.8,12
An occlusal splint is a removable appliance covering some
or all of the occlusal surfaces of the teeth in either the
maxillary or mandibular arches. The ideal occlusal splint is
made from laboratory-processed acrylic resin, which should
cover the occlusal surfaces of all the teeth in one arch. It
should provide even simultaneous contacts on closure
on the retruded axis with all opposing teeth and anterior
guidance causing immediate disclusion of the posterior
teeth and splint surface outside intercuspal position.8
Occlusal splints should be worn according to the dentist’s
recommendation for considerable periods of time to be
effective. If a splint does not cover all the occlusal surface
in an arch, unopposed teeth will continue to erupt creating
an iatrogenic malocclusion. This applies to both anterior
and posterior partial coverage splints, and their use cannot,
therefore, be recommended.7,8,13-15 Our patient has used an
anterior bite plane for two years, and consequently the
anterior open bite has developed.
An anterior splint would permit the posterior teeth to erupt
so that when the splint was removed, the anterior teeth
would be apart and anterior guidance would have been
lost. 8,16-18 (Figure 8) The same findings were observed in
this patient. The anterior bite plane caused abnormal space
between maxillary and mandibular anterior teeth. The
posterior teeth may have been prolonged or the anterior
teeth may have been buried. We do not know this exactly
56
Figure 8. Splint in the mouth
Figure 9. Splint in the mouth (open mouth position)
The Treatment of Bruxism
Figure 10.Four types of permissive splints. All permit free horizontal
movement of the mandible. Remember that while the anterior part
of the mandible is moving horizontally, the condyles must travel
down and up the eminentia to move the jaw horizontally. Keep that
in mind for any splint design. Permissive splints must have one side
smooth. A. Anterior bite plane-flat surface separates all posterior
teeth. B. Posterior bite plane-splint permits horizontal movement but
becomes a pivot point for the last tooth as condyles move upwardly.
C. Full occlusal splint on the upper works the same as full lower splint.
D. Both have some pivotal effect on the most posterior teeth as
condyles move back and up. (From Dawson)
(canine guidance). All centric relation contacts are even and
on flat surfaces. Eccentric guidance occurs on the canines.8
Owing to these advantages, a centric relation splint was
fabricated for this patient.
Occlusal splints are typically made of a heat-cured acrylic
resin. Soft acrylic or light cured composite, or vinyl splints
may be made more quickly and cheaply, but are not as
durable, and are more commonly made for short-term use.
Soft splints are also used for children, because normal
growth changes the fit of hard splints.18-20 A heat-cured
acrylic resin was preferred to make the splint. To protect the
tooth and restoration surfaces, and to manage mandibular
(jaw) dysfunction, we suggested the patient wear the splint
all night.
To close the anterior open bite was possible through an
anterior fixed restoration and orthognathic surgery that
will have impact on the posterior maxilla, which allows the
mandible to autorotate, thereby decreasing the anterior
facial height. However, we choose splint therapy because
of bruxism and follow-up the anterior teeth extrusion by
non-contact anterior splint. We observed that the space
decreased; and we continued to follow-up.
CONCLUSION
Figure 11.A. Anterior bite plane in place. Notice the relationship of
the lower anterior teeth to the bite plane surface. The contacting
surface should guide the lower incisors sligthly downward during
protrusion. B. Interocclusal space should be ample to prevent all
posterior contact in centric or any excursion. The condyles should
be free to seat upward with no interference of any kind from the
posterior teeth. (From Dawson)
as it was not us who had fabricated the first splint. Her
speech had changed. The patient could not produce a clear
“s” sound and was aware of the distortion in her speech.
A centric relation splint is a hard full-arch acrylic appliance.
Either arch can be used, but the maxillary provides some
advantages. The maxillary splint is usually more stable
and covers more tissues, rendering it more retentive and
less likely to fracture. During a laterotrusive movement the
mandibular canine discludes the remaining posterior teeth
Anterior bite plane provides occlusal contacts only on the
anterior teeth. Parafunctional activity associated with
unfavorable posterior tooth contacts can be treated with
it but only for short periods. There can be some major
complications when an anterior bite plane or any splint is
used to cover only a portion of one arch. The unopposed
posterior teeth have the potential to supererupt. If the
appliance is worn continuously for several weeks or months,
there is a great likelihood that the unopposed mandibular
posterior teeth will supererupt. When this occurs and the
splint is removed, the anterior teeth will no longer contact
and the result will be an anterior open-bite. Anterior bite
planes should not be left worn for extented periods.
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