Development and design of novel prosthetic total temporomandibular joint (TMJ) reconstruction system in patients with temporomandibular joint disorder

Work on Temporomandibular Joint (TMJ) at tertiary care centers like Maulana Azad Institute of Dental Sciences, Delhi, is being carried out for multiple decades. However, these institutes still rely on autogenous grafts for the reconstruction of temporomandibular joint. This not only creates a second surgical site but also carries the risk of patient morbidity and graft resorption. Thus, an optimal treatment alternative is not available for these patients. Out of multiple options for reconstruction of the temporomandibular joint, prosthetic joint replacement is associated with a single surgery which causes less donor site morbidity. Commercially available pre-fabricated TMJ prosthesis does not fit the Indian population as they have been designed according to the Caucasian population, it cannot fit the patient population in India. The alternative to this is custom -made patient specific TMJ prosthesis which is designed according to the patient anatomy. Patient specific TMJ prosthesis is not available commercially in India, and it is not cost effective around the world (average price around 20,000 USD). Due to absence of complete range of motion with stock prosthetic TMJ, the mouth opening remains less. Inability to open the mouth is an impediment to patient to eat, speak.

Prosthetic joints available in the market also do not have any arrangement to incorporate lateral pterygoid muscle which is required for proper mouth opening without jaw deviation and performing lateral movements of the TMJ. In view of the above problems an innovative design was created by the investigators that would facilitate translation as well as rotational movements with a slot to incorporate the lateral pterygoid muscles. To achieve these objectives, the investigators comprehensively planned the reconstruction of glenoid fossa and reattachment of the lateral pterygoid muscle to the prosthetic TMJ to support normal functional occlusion and mandibular motion. The innovative design of prosthesis is based on the biomechanics of the natural temporomandibular joint and is focused on 4 main outcomes: Maximum mouth opening and lateral movements, pain reduction, dietary restitution, and quality-of-life improvement. As a result, the results from this project would help to outline that re-establishing functional and structural mechanics is a critical goal and influences total TMJ replacement surgical success. The modification in the design of the prosthesis aims to improve the clinical success of total joint prosthesis in restoring mouth opening and complete range of mandibular movements. During total joint replacement, the proper reattachment of the lateral pterygoid on condylar neck of the mandibular component is necessary for the proper grinding of food. Similarly, the change in glenoid fossa design will influence the range of mandibular movements which may directly influence the vital functions of speech, mastication and overall quality of life.