Sex-specific 3D Quantitative TMJ Morphometry: CBCT, MRI, Physical Measurements

Objectives: Unknown etiological factors contribute to temporomandibular joint disorder (TMJD) development and progression, and its increased prevalence among women. Temporomandibular joint (TMJ) morphometry may be predictive for TMJD development. Various methods have been utilized to evaluate TMJ morphometry including CBCT, MR and physical measurements, however there has been no cross-comparison of morphometric measurements evaluating differences in measurement techniques and only limited sex-specific morphologic analysis. This study was to compare sex-specific condyle and disc morphometry from CBCT images, MR images and physical measurements on intact human TMJs.
Methods: 19 cadaveric heads, 9 females (71.2±10.0 years) and 10 males (73.7±9.1 years) with no evidence of pathology underwent CBCT, and had their TMJs removed en bloc. High-resolution 7T preclinical MR scans were obtained of intact TMJs. Unsmoothed surface models were reconstructed from CBCT and MR images. TMJs were dissected and physical measurements of the TMJ disc and condyle were made using digital calipers. Differences in condyle and disc 3D morphometry was determined by two-way ANOVA with fixed effects measurement source and donor sex.
Results: Condylar features were successfully captured by CBCT (resolution: of 0.5x0.5x0.5 mm), condylar and disc features were successfully captured by MR (resolution: 0.234x0.234x0.5 mm), and condyle and disc features were successfully measured using digital calipers. Condylar and disc morphometric parameters were condylar major and minor axes, condylar height, condylar lingual length and buccal length, disc mediolateral and anteroposterior length, disc thickness at the anterior band, medial disc aspect, intermediate zone, lateral disc aspect, and posterior band.
Conclusions: TMJ condylar and disc morphometry varied significantly between sexes, and by measurement source. Sex-specific differences in condyle and disc size and shape is anticipated to alter contact mechanics between males and females. Differences in morphometric outcomes between CBCT, MR and physical measurements is critical when considering the development of accurate TMJ models.