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.