Subluxation or dislocation of the temporomandibular joint (TMJ) is an acutely painful condition in which the condyle glides out of the glenoid fossa with  inability to descend back to normal position. The incidence of dislocation is 7% .  It occurs due to imbalance in the neuromuscular function, structural variation in eminence, fossa, or condyle and laxity of the ligaments &capsule. Dislocation is precipitated spontaneously or by trauma,aging and changes in the dentition, wide mouth opening, certain antipsychotic medications, and some syndromes. Dislocation is commonly mismanaged because of improper localization of pathology. The treatment for TMJ Dislocation is generally done based on creating or removing the obstacle in condylar movement. Here, in this study we are going to measure the osseous anatomy of  TMJ components to determine the discrepancy using Cone Beam Computed Tomography (CBCT).  The CBCT allows measurement of  TMJ bony structures with high accuracy. Also proposing new Diagnostic Algorithm to choose the Ideal treatment option for the respective discrepancy.

RESEARCH AIM:

          This study was therefore designed to analyze the discrepancy in the osseous component of the TMJ and to propose a diagnostic algorithm to choose the ideal treatment protocol.

MATERIALS AND METHODS:

o   SAMPLE SELECTION: 50 patients with age of 18 to 50 were recruited into the study and  allotted into two groups.

CONTROL GROUP:(n=25)Patients with no history of subluxation.

STUDY GROUP:(n=25)Patients with history of subluxation.

o   Clinical evaluation included assessment of mouth opening, clicking and pain.

o   Radiologic evaluation using CBCT.

o   PARAMETERS: CBCT evaluation included measurement of

                             -width and height of condylar head.

                             -width, height and inclination of articular eminence.

RESULTS/FINDINGS:

          To compare mean and standard deviation of parameters between study and control groups independent samples unpaired t-test was applied. For variables which did NOT follow Normal distribution, to compare between study and control groups wilcoxon test was used.

CONCLUSION:

          Relative ratio of the depth of glenoid fossa to height of articular eminence which can predispose to dislocation was determined. This was called the critical ratio. Patients with lower critical ratio required osseous surgery while patients with higher ratio required soft tissue surgery.