The Relationship between Temporomandibular Joint Disc Displacement and Face Form

Aims: To evaluate whether patients diagnosed with Temporomandibular Joint Disc Displacement (DD) tend to have longer faces (hyerleptoprosopy). Materials and Methods: 36 females patients diagnosed with DD in the Orofacial Pain & TMD Clinic, Tel Aviv University, and 36 asymptomatic participanted in the study. The following anatomic parameters were studied: At the frontal plane – total face length and width were measured and the ratio between the two was calculated [Total Facial Index (TFI) – used for defining facial form]; at the sagittal plane – the sagittal width, ramus height, the mandibular body length and the entire mandibular length. Results: Statistically significant differences were identified between the two groups pertaining to the following two parameters using the t-test: TFI (p = 0.04) and ramus height (posterior facial height, p = 0.035). The symptomatic group demonstrated a higher TFI value (characterized by longer facial form) compared with the asymptomatic group (91.8% ± 4.9 and 89.2% ± 5.5, respectively). Moreover, the proportion of participants with the utmost longer facial form (hyperleptoprosopy) was significantly greater in the symptomatic group compared with the asymptomatic group (39% and 14%, respectively). The ramus height was shorter in the symptomatic group than in the asymptomatic group (5.37 ± 0.54 cm, and 5.6 ± 0.32 cm, respectively). Several statistically significant correlations were found between the various parameters measured, the most important was the negative correlation between the TFI and the ramus height (r = -0.26, p = 0.03). Conclusions: These findings show that a long facial form is more prevalent among young females diagnosed with DD compared with the general population. The negative correlation between the TFI and the ramus height implies that an obtuse gonial angle could be present in individuals with a short ramus height, which results in a longer face.