Medicine/Clinical medicine
Fastovets’
O.O.
Dnipropetrovs’k state medical academy, department of prosthetic dentistry
Prevention of Mandibulotemporal
Joint Pathology in Treatment of Initial Degree of Pathological Tooth Wear
Restoration of crowns’ integrity at the initial stages of pathological tooth wear has not so
much aesthetic
importance but preventive one because it is directed on avoidance of
mandibulotemporal joint dysfunction related interalveolar height reduction. For today direct composite restorations
of worn dental surfaces
are widespread that
is fully justified by
properties of modern sealing materials.
Due to including to their composition over 70% ion-organic filling
they have increased wear-resistance,
capability to sustain
masticatory pressure; they don’t wear away and thus the height of bite is retained. Direct modeling of teeth|immediately| in an oral cavity is able to provide exact observance of sizes and forms of crowns. However taking into
account importance of renewal
incisor and canine conducting, the special trouble has
been caused by traditional setting upper frontal teeth height arbitrarily,
according to cosmetic considering. In that time restoring frontal teeth length renews
height of mesial and lateral occlusion. In the same queue their correct anatomic form normalizes occlusion “automatically”. Besides from positions of
harmonic dynamic occlusion it
is expedient to control
character of lateral
teeth occlusion during direct restorations. Coming from above-mentioned, at
pathological tooth wear modeling of direct restorations in articulators is desired condition of recreation of valuable functional occlusion. Consequently, the purpose of the work was
defining prophylactic efficiency of direct composite restorations controlling in
articulator for warning of mandibulotemporal joint disturbance.
Materials and methods of the research. It was examined 28 patients with the initial degree of generalized
pathological tooth wear, who had intact dentitions and orthognathic bite,
equally men and women, whom middle age was 37,0±3,1 years. They did not have
disorders in mandibulotemporal joints and parafunctions of
masticating muscles. The horizontal form of disease was diagnosed in 60,7±9,2% patients, at others tooth wear had mixed character (it was vertical in
the area of frontal teeth and horizontal for lateral ones). At external
examination insignificantly expressed facial signs of interalveolar height reduction were registered in 71,4±8,5% patients. In position
of physiology rest the average distance between upper and lower frontal teeth
in vertical direction was 3,9±0,8 mm.
The reconstruction of dentitions was carried out
after complex remineralization
and measures of
normalization
of acid-alkaline balance. Ñompomer
“Dyract AP” was used for
restoration of lateral teeth,
composite material “Spectrum
TPH” – for frontal group. For
renewal of occlusal surface
and contacts of premolars and molars elements of wax modeling techniques “tooth
to tooth” (Thomas P.K.) and “tooth
to two teeth” (Payne E.V.,
Lundeen H.C.) were applied. Verification of correctness
of direct restorations forming was analyzed from positions of functional occlusion due to the method
of diagnostic
“wax-up” on models plastered in
an articulator. After wax
modeling it was got the
“silicon key” which
facilitated restoration in
oral cavity.
In 3 years the efficiency of the treatment is estimated after the
symptoms of
interalveolar height preservation,
further progressing of
pathological process,
presence of signs of mandibulotemporal joints dysfunction by Helkimo. For objectivity of results we
applied odontometric measuring of crowns height of first
upper and lower molars|jow| as as the teeth which retain the height of bite (it was determined on control models
by trammel head).
Results of the research. There were 311 direct restorations of worn teeth of different
functional groups in the research. In 3 years stabilizing of disease was marked
in 96,3±3,6% of examined patients, what was confirmed by the interalveolar
height preservation (the average distance between dentitions was
2,4±0,5 mm). Pathological symptomatology
in mandibulotemporal
joints including the signs of jaw mobile, function of
joints, muscular and articulate pain, pain during motions of jaw was absent (the middle clinical index of
disfunction by Helkimo was 0,1±0,03 points). Only registered in 1 patient
clinical picture was testified as progressing process, so as it was characterized
marginal adaptation destruction and considerable wear of not only restorations
but also intact teeth, however mandibulotemporal joints
disorders was not determined. We explained a similar negative result by bruxomania
which was not diagnosed on beginning of treatment. So such a clinical situation
needed another therapeutic tactics.
By the data of the analysis of control models the average height of
crowns of upper first
molars at once after treatment was 8,15±0,28 mm against 8,15±0,30 mm in 3 years.
Accordingly these
indexes for first lower molars were 7,80±0,40 mm against 7,73±0,40 mm. Thus statically meaningful differences (ð>0,05) were not set for results of
odontometry in terms
directly after
treatment and in 3 years after, that proved the
interalveolar height preservation on the whole.
Conclusions.
According to the results of the research the direct composite restorations,
reproduced in an articulator, are capable to prevent mandibulotemporal joint disorders due to exact renewal of occlusal dental surfaces, forming of
dense occlusal contacts and permanent normalization of height of bite.
Restoration of incisor and canine conducting allowed to warn further wear of lateral teeth, to avoid appearance of
balancing and hyperbalancing supercontacts, to normalize the functional loading
on joints.
The
creation of stable contacts of lateral
teeth and the exact protrusion and
laterotrusion conducting functions is necessary for occlusal harmony.
Restoration of occlusal surface relief of premolars and molars has to provide the stable occlusal support. The
necessary condition of
efficiency of distal support restoration is occlusion with fissure-hillock contacts
building. Thus
functional vertical
and horizontal interrelation of upper and lower jaws is formed at physiology height of occlusion which gives resistance terminal forces|strenth| at mastication and swallowing, sending loading along the axes of
teeth.
For
central occlusion it is necessary to restore the
one-stage bilateral contact of supporting
hillock with conforming
fissures and marginal crimps. Also it follows to conduct
restoration of lateral group of teeth taking into account the features of
protrusion motions of mandible. Incisor track have to provide instantaneous opening of
lateral teeth at jaw moving forward from position of central
occlusion.