Evaluation of temporomandibular joint disc displacement via MRI and computerized axiography: a case report

Magnetic resonance imaging (MRI) is commonly used as a reference imaging modality for evaluating the temporomandibular joint (TMJ) disc-condyle relationship because it provides direct visualization of the articular disc in closed- and open-mouth positions. However, routine MRI primarily provides structural information at static mandibular positions and may not adequately reflect dynamic mandibular function. Consequently, discrepancies between imaging findings and clinical symptoms or treatment response may create diagnostic uncertainty in selected patients. Computerized axiography records mandibular movement trajectories and condylar motion and may provide supplementary functional information in selected cases; nevertheless, its interpretation remains limited by operator dependency, recording conditions, device-related differences, and the absence of universally accepted diagnostic thresholds. Importantly, structural abnormalities identified by MRI do not always correspond directly with functional mandibular performance or short-term treatment response, which may create challenges in the interpretation of individual clinical cases.

A 22-year-old female presented with a 3-month history of bilateral TMJ clicking and localized pain in the left joint. According to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) Axis I criteria, the clinical findings were compatible with bilateral disc displacement with reduction, based on a history of TMJ noises and examiner-detected reciprocal clicking during opening and closing. MRI further demonstrated bilateral anterior disc displacement with reduction (ADDwR). An anterior repositioning splint (ARS) was prescribed; however, the patient reported aggravation of symptoms in the left joint. The splint was discontinued, and computerized axiography was performed using the CADIAX Compact II system to further characterize mandibular movement patterns and provide additional functional observations. The mandibular opening-closing trajectory showed an "8-shaped" non-overlapping pattern with incomplete overlap between repeated movement cycles, and the protrusive condylar path length was shorter on the left side than on the right side (approximately 3-4 mm versus 10-11 mm). These findings were interpreted as supportive functional observations suggesting restricted left protrusive condylar translation and reduced movement reproducibility, rather than as definitive diagnostic evidence. Considering the patient's symptoms, MRI findings, and functional movement observations, treatment was subsequently modified to a pivot splint. Short-term follow-up showed improvement in symptoms and mandibular movement trajectories, and post-treatment MRI showed a more favorable disc-condyle relationship.

Findings from this individual case should be interpreted as exploratory and hypothesis-generating. In this case, computerized axiography provided supplementary functional information when routine MRI findings did not fully explain clinical symptoms or treatment response. However, the present single-case observation cannot establish causality, treatment efficacy, diagnostic accuracy, or generalizable clinical indications. Larger prospective studies with standardized MRI/CBCT and axiographic protocols, cross-device comparability, and long-term follow-up are required.