Mandibular asymmetry as a possible etiopathologic factor in temporomandibular disorder: a prospective cohort of 134 patients.

OBJECTIVES: The present study aimed to investigate mandibular asymmetry as a possible etiopathologic factor in temporomandibular disorder (TMD). MATERIALS AND METHODS: A prospective cross-sectional study of patients with dentofacial deformities seeking corrective orthognathic surgery was conducted. The pre-operative prevalence of TMD in patients with mandibular asymmetry and other dentofacial deformities was assessed using the Diagnostic Criteria for TMD (DC/TMD) Axis I protocol. RESULTS: A total of 134 patients were recruited - 82 with mandibular asymmetry and 52 without. There was a significantly higher prevalence of TMD in those with mandibular asymmetry (67.1%; 95% CI 59 to 75%) compared to those without (40.4%; 95% CI 32 to 49%, p = 0.002). The overall pre-operative prevalence of TMD in this population of patients was 56.7% (95% CI 48 to 65%). Pain disorder only was present in 9.7%, TMJ disorder only in 29.9%, and both pain and TMJ disorders in 17.2%. The most prevalent type of TMD is disc displacement with reduction (77.6%), followed by myalgia (35.5%) and arthralgia (21.1%). CONCLUSION: The prevalence of TMD in those with mandibular asymmetry was significantly higher than those without, suggesting that mandibular asymmetry could be a possible etiopathologic factor in TMD. CLINICAL RELEVANCE: The significantly higher prevalence of temporomandibular disorder in those with mandibular asymmetry suggests that we need to be especially cognizant of this condition in our pre-operative, surgical, and post-operative management of this group of orthognathic patients.