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.

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House of Gnathology?

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Arthrogeneous origin of TMJ pain, Asymmetry, Bruxism, Centric relation, condylar asymmetry recognition, Dentistry, Myogeneous origin of TMJ pain, Occlusal adjustment, Oral Stability, Retruded Position of the Mandible, Temporomandibular joint diagnostics, Temporomandibular joint disorder, Temporomandibular joint pain, TMJ rehabilitation, Treatment planning

A week ago I had the pleasure to attend the XXVII International AIG (Associazione Italiana di Gnatologia) Congress in Torino, Italy. Twentyseven speakers from six countries each had about 30 minutes to present their thoughts about the relationship between occlusion and temporomandibular joint disorders. In general it could be concluded that a stable occlusion would improve the function of the stomatognathic system and thereby reduce the risk for developing or aggravating a temporomandibular joint disorder. It was also underlined in several lectures that gnathology is a team work and that occlusion is one tool in the treatment of a temporomandibular joint disorder.
It was interesting to note that the speakers in general agreed in finding occlusion an important factor in the treatment of a temporomandibular joint disorder, i.e. a complete contradiction to the conclusion of several hundreds of articles and studies proclaiming that when RDC/TMD are used in the evaluation of treatment outcome occlusion is not important and should not get priority or most often not even be considered in the treatment of a temporomandibular joint disorder.

RDC/TMD were discussed and by a great part of the participants even questioned in the final round table discussion of the congress. In my opinion and in agreement with many other clinicians RDC/TMD cannot and should not be used in the clinical situation in which a specific diagnosis is to be the sound base for the treatment. Reliable criteria like maximum mouth opening, mandibular movements, the difference between dynamic and static pain and even the difference between the vertical dimensions of the two temporomandibular joint condyles visible and measurable in a panoramic X-ray exist. Therefore my suggestion to the RDC/TMD supporters is: Next time you conduct a clinical study, why not incorporate the above mentioned criteria! I am pretty convinced that the results will be different regarding the eventual link between occlusion and the temporomandibular joint disorder.

Finally I would delete the ? from the title of this blog and agree with the suggestion from Dr.Eugenio Tanteri that a forum “House of Gnathology” might come to an agreement that a correctly designed and applied occlusion is important in providing  oral stability and thereby reduce the prevalence of temporomandibular joint disorders among our patients.

Indices for jaw registrations

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Bruxism, Centric relation, condylar asymmetry recognition, Dentistry, Mounting casts, Occlusal device, Occlusal splint, Occlusion, Retruded Position of the Mandible, TMJ rehabilitation

Sometimes it can be difficult to get a relaxed mandible in the process of jaw registration in the retruded position of the mandible in as well the diagnostic phase as in the steps of treatment. It happens mostly when the patient is a heavy bruxer or when the patient seems to defend him/herself against the pressure from the hands of the dentist in the clinical situation. A condylar asymmetry may add to the clinical difficulty in getting the registration right.
With the measurements of the vertical dimensions of the temporomandibular joint condyles and the Maaxloc device at hands the above mentioned problems can definitely be reduced.It is my opinion, which to a great extent I have achieved from the dental technicians, that the registrations made in the Maaxloc system get into a more retruded position of the mandible in comparison with the manually taken clinical indices which often are protruded.This conclusion is based upon several years of cooperation with Ines Selimanovic T.I.C. laboratory, Malmoe ,Sweden, an experienced dental technician, with whom I have made comparisons of by me taken clinical indices and by her made registrations in the Maaxloc device.
In conc;usion: To avoid unnecessary and time consuming adjustments despite quality of the dental work in the ” difficult mouth “it might be worth while to become critical to the manually taken clinical registration and consider the advantage of the Maaxloc device.

Mounting casts

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Asymmetry, Asymmetry Index, Centric relation, condylar asymmetry recognition, Dental laboratory work, Dentistry, Mounting casts, Occlusal adjustment, Occlusal device, Occlusal splint, Occlusion, Oral rehabilitation, Oral Stability, TMJ rehabilitation, Treatment planning

The other day I had to check the mounting of the casts of the upper and lower jaws of a patient with a condylar asymmetry of about 6%. The reason for my visit to the dental laboratory was that the right side lower four units bridge had been redone and several times before that adjusted. And yet the patient found it too low i.e. her teeth of her right side did not contact in occlusion unless she  forced her mandible to the right.

During the visit at the laboratory it became once again obvious to me from the discussions with two well experienced dental technicians that very often the indices to be used in mounting the casts cannot be used. The indices are perforated and mostly show slides in the material used indicating that the mandible of the patient has not been stable at the time of index registration.  Therefore the technicians try to analyze different facets of the occlusal surfaces of the casts. They try to fake the movements of the patients mouth that have created them and thereafter, still manually, they fix the casts in the position which seems to  be the starting point for the suspected movement.This position usually is looked upon as the intercuspal position and will be used for the subsequent mounting of the casts.

At a condylar asymmetry it is therefore easy to understand that with the above described mounting of the casts the crowns or bridges of the ” shorter condyle ” side will be too low. Clinically oral stability will be lacking despite the insertion of the prosthodontic work. Very often tooth contacts of the ” higher condyle  ” side will be looked upon as occlusal interferences and removed in an ” adjustment “.This actually results in a decrease of the vertical dimension and a not one hundred percentage satisfied patient.

The problem and frustration can easily be avoided if the vertical condylar asymmetry is transferred into the Maaxloc instrument. A registration at the clinic or at the laboratory is made  and used in mounting the casts with the result that mostly the prosthodontic work can be inserted  without any adjustment at its delivery.

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.

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 !