Differences in morphology of temporomandibular joint ankylosis of traumatic and infective origin

The aim of this study was to determine whether there are any differences in morphology between temporomandibular joint ankylosis (TMJA) of traumatic and infective origin. Cone beam computed tomography (CBCT) scans of 25 patients (28 joints) with TMJA of traumatic origin (trauma group) and 15 patients (15 joints) with TMJA of infectious origin (infection group) were included. The following morphological parameters were evaluated on multiple sections of the CBCT scans: lateral juxta-articular bone growth, residual condyle, residual glenoid fossa, ramus thickening, ankylotic mass fusion line, sclerosis of the ankylosed condyle and spongiosa of the glenoid fossa, and mastoid and glenoid fossa air cell obliteration. Lateral juxta-articular bone growth, juxta-articular extension of fusion, and the presence of normal medial residual condyle and residual glenoid fossa were exclusively found in post-traumatic TMJA. There were differences in ramus thickening (82.1% in trauma vs 53.3% in infection), sclerosis of the ankylosed condyle (100% in trauma vs 60% in infection), and sclerosis of the spongiosa of the glenoid fossa (100% in trauma vs 46.7% in infection) between the trauma and infection groups. Mastoid and glenoid fossa air cell obliteration was found more frequently in the infection group (mastoid obliteration: 23.1% in infection vs 4% in trauma; glenoid obliteration: 66.7% in infection vs 55.6% in trauma ). CBCT imaging can be helpful in differentiating between TMJA of traumatic and infectious origin.