Occlusal Adjustment at a TMJ Condylar Asymmetry?

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Asymmetry, Centric relation, condylar asymmetry recognition, Dental treatment, Dentistry, Occlusal adjustment, Occlusion, Preprosthetic occlusal adjustment, Retruded Position of the Mandible, TMJ rehabilitation, Treatment planning

Be careful! The tooth contacts which seem to be occlusal interferences at the first sight when the conventional retruded contact position of the mandible is being executed may not be disturbing tooth contacts at all. If they are located on the higher condyle side they may denote the vertical dimension of the inter maxillary relationship and should in my opinion not be removed. Only precontacts on the shorter condyle side are to be looked upon as true interferences and can be removed to such an extent that tooth contacts are established on the higher condyle side.

With the risk of repeating myself I  do want to advise the clinician to build up the occlusion on the shorter condyle side instead of adjusting the teeth through occlusal adjustment on the higher condyle side.In this way we will secure a correct vertical dimension between the two jaws in occlusion and thereby rescue the patient from a too low vertical dimension of the occlusion after completed dental work often jeopardising the function the temporomandibular joints.

Cutting Temporomandibular Joints

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Asymmetry, condylar asymmetry recognition, Dentistry, Implantology, Occlusion, Orthodontics, Preprosthetic occlusal adjustment, Prosthodontics, Radiography, Temporomandibular joint, Temporomandibular joint disorder, Temporomandibular joint pain, Treatment planning

occurs in surgery. Thank God it does not happen too often, as responsible, well trained and experienced oral / maxillofacial surgeons are utmost cautious. They know it is involved with major draw backs. However, under certain circumstances and with the correct indications it is  necessary. I do not mind that at all, but what I do mind is all the cutting of temporomandibular joints in the panoramic x-rays we are exposed to in the literature and thus unconsciously gives us the message that the joints are not so very important.

It does not matter whether it is in a professional journal of prosthodontics, orthodontics, implantology, periodontics or even in a presentation at a congress it could be estimated that 8-9 out of 10 panoramic x-ray photos presented do not show the entire picture of the two temporomandibular joint condyles. The majority of condyles are cut totally  or at least partially while all the teeth are nicely depicted and aligned in the perfect occlusal plane  often before as well as always after treatment.  Is a vertical condylar asymmetry present in such a patient most likely the teeth are not aligned in the shown or anticipated correct occlusal plane. With a high probability the smile of that patient is tilted which is observed in the clinical situation and which often also might be the reason for the complaint of  the not satisfied patient.

In rehabilitation priority is supposed to be given to the whole stomatognathic system and not only to one third of it. As the other two thirds of the system ( the masticatory muscles and the two temporomandibular joints ) are dependent on the teeth it is my advice that the teeth must be aligned in such a way that they vertically compensate for what is missing in the vertical dimension of the shorter condyle when present. Addressing the vertical condylar asymmetry, when present, is of utmost importance and  in my opinion it should be done already at the time of treatment planning regardless specialty of the therapist. To incorporate an index, preferably via Maaxloc, between the models already at the initial analysis of the ” study ” models instead of just manually having the models to occlude will definitely contribute to a bigger certainty in reaching the goal of treatment. It makes the whole planning easier and it decreases the risk of unnecessary difficulties during treatment. In not accepting cut temporomandibular joint condyles in the panoramic x-ray and instead  only accepting  the picture when it is  complete i.e. picturing  both the temporomandibular joint condyles we most probably will be  expanding our clinical success and consequently patient satisfaction.

Uneven Front Teeth Wear

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Asymmetry, Bruxism, Centric relation, condylar asymmetry recognition, Dentistry, Occlusal device, Occlusal splint, Occlusion, Orthodontics, Preprosthetic occlusal adjustment, Retruded Position of the Mandible, Reversible treatment, Temporomandibular joint, Temporomandibular joint disorder, Temporomandibular joint pain, Treatment planning

may very well denote a temporomandibular joint condylar asymmetry and may therefore indicate the necessity of a panoramic x-ray in order to avoid negative consequences of a dental treatment. It is my experience that very often the front teeth ( the central and the lateral incisors ) of the quadrant of the ” higher condyle ” side are more worn than the equivalent teeth of the contra lateral side. The ” higher condyle ” side seems with a far more higher prevalence be used as the laterotrusive side ( working side ). The contra lateral side of the face then also looks bigger or thicker, most probably due to the unilateral hyperactivity of the superficial masseter muscle of that side. When this kind of an observation is made there is an absolute indication to proceed with a clinical examination in order to rule out whether pain or discomfort are involved.

If pain is present the stomatognathic system needs to get normalized. This is easily accomplished with the insertion of a correctly designed stabilization splint. The splint preferably already at the dental laboratory is  fabricated in the correct relation between the models i.e. the models have been mounted in an articulator according to the index ( registration ) made in the Maaxloc and thereby based upon the difference between the two condylar heights. Within a couple of weeks, not to say surprisingly often within a couple of days, the patient returns with markedly reduced pain or completely without pain. Also without any difficulties the patient normally finds his / her natural way in getting his / her teeth together. However,on the ” shorter condyle ” side tooth contacts are missing. This most often results in a slide between the mandibular reference position, RPM, and the intercuspal position and therefore often indicates a need for extended dental treatment or at least a change of direction of your earlier planned treatment.  The empty space between the teeth of the ” shorter condyle ” therefore needs to be filled in or the teeth of the ” shorter condyle ” side need to be built up. After four to six months and with a reversible approach in form of a partial and casted metal splint cemented on the not occluding teeth of the ” shorter condyle ” side oral stability is achieved. Personally I always have that splint casted in gold and made for the lower premolars / molars. The earlier worn stabilization splint is being adjusted to the new and reversible occlusion and is used part time, during sleep for an individually determined length of time. Finally permanent treatment can be considered at the choice of you and your patient.

Uneven front teeth wear occurs and is also sometimes observed in young patients.In these individuals it may be even more important to analyze the vertical dimensions of the two temporomandibular joint condyles. At a condylar asymmetry an index via Maaxloc may serve as an adequate guide to relate the upper and lower models of the teeth, indicating the correct vertical dimensions of the jaws after completed treatment and thereby contribute to the best outcome of the orthodontic treatment. In not addressing the condylar asymmetry, when present, in the initial phase of treatment planning there is always the risk to deliver a yet perfect occlusion but in a not perfect occlusal plane, i. e. a perfect smile what concerns the teeth but less perfect what concerns the smiling mouth of the whole face.

 

Occlusal ” interferences ” at condylar asymmetry

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Asymmetry, Centric relation, condylar asymmetry recognition, Dentistry, Occlusal adjustment, Occlusal device, Occlusal splint, Occlusion, Preprosthetic occlusal adjustment, Retruded Position of the Mandible, Temporomandibular joint, Temporomandibular joint disorder, Temporomandibular joint pain

must be carefully evaluated before any action is taken. It is as important and necessary to realize as it is absolutely wrong to adjust occlusal  pre contacts in the acute situation of functional facial pain.The latter  ” interferences ” may not be real as they might not exist under normal or pain free circumstances. They might be due to changed muscular conditions in the dysfunction of the stomatognathic system and most probably they will disappear with a normalization of the function. In my opinion it is therefore an absolute necessity to always normalize the muscle function via reversible means before any change of the occlusal surfaces takes place. This is done through the insertion of a stabilization splint made in the correct mandibular position, based upon the findings of the condylar heights visible in the panoramic x- ray, and worn according to the preliminary diagnosis during 4-6 months . Not until then an occlusal adjustment can be considered.

Although occlusal pre contacts cause an oral instability with mostly a slide between the retruded position of the mandible ( RPM ) and the intercuspal position ( ICP )  pre contacts on the ” higher condyle ” side may indicate the true vertical dimension of the occlusion ( the static relation between the teeth of the maxilla and of the mandible ).Therefore these contacts will function as the guide  for an increase of the vertical dimensions of the teeth not in contact  on the opposite side in equivalent regions. Thus ,it is my advice that, occlusal pre contacts on the ” higher condyle ” side should not be removed. If so, there is a major risk that the vertical dimension will get decreased and problems due to a too low vertical dimension of the occlusion will occur.

Occlusal pre contacts on the ” shorter condyle ” side  in the retruded position of the mandible ( RPM ) most likely are true interferences and can therefore be removed after a normalization of the muscle function. They should also be removed prior to the introduction of new elements into the occlusion via prosthodontics.

At condylar symmetry i.e. when the two condylar heights are of equal size, pre contacts in the retruded position of the mandible ( RPM ) should be removed pre prostodontically. If no further rehabilitation is planned or indicated these pre contacts can be left unless they produce a  major lateral slide between the retruded position of the mandible ( RPM ) and the intercuspal  position (ICP ).The general rule remains: DO NOT CONTRIBUTE TO UNNECESSARY CHANGES OF THE OCCLUSION IN A PATIENT WITHOUT PAIN !  NEVER APPLY  OCCLUSAL ADJUSTMENT AS A PURE PREVENTION !