According to recognized guidelines, a total alloplastic replacement may be indicated to resolve temporomandibular pain and functional limitations in cases where conservative and less aggressive surgical management strategies have failed. It is broadly believed that, as a result of the surgical procedure, the function of the lateral pterygoid muscle is lost and so are the laterotrusive and protrusive jaw movements. Furthermore, the joint prosthesis design may not be conducive to lateral and protrusive movements. Using a dynamic stereometry technique, it was possible to perform a quantitative analysis of kinematics in TJR patients. The cases of four patients who showed preserved lateral and/or protrusive motion are presented here. During mouth opening, prosthetic condyle translation ranged from 3.18mm to 10.09mm and it was also possible to observe this clinically. It has been suggested that changes in prosthesis design may have improved postoperative jaw kinematics. Considering the large diversity in treatment outcomes, it is recommended that the individual prognosis should always be discussed with the patient prior to surgery.
Keywords: arthroplasty; biomechanics; joint replacement; mandibular motion; temporomandibular joint.
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