LAUSR

BACKGROUND Patients with dentofacial deformity often present with impaired masticatory function, orofacial pain, and temporomandibular disorders (TMD). This study investigates the relationship between TMD, pain, jaw, and masticatory function at different stages of orthognathic surgical (OS) treatment. METHOD A total of 120 OS patients were prospectively recruited and grouped as pre-orthodontic (group 1), pre-surgery (group 2), 4-month post-surgery (group 3), 24-month post-surgery (group 4), in addition to 30 controls (group 0). Outcomes were assessed using: Jaw Function Limitation Scale (JFLS), McGill pain questionnaire, DC/TMD instrument, voluntary maximum bite force (MVBF), and masticatory efficiency (ME) using two-colored chewing gum. Data were analyzed using structural equation modeling. RESULTS The prevalence of non-painful TMD did not differ between groups (P = 0.827). However, the prevalence of painful TMD differed between groups (P = 0.001). Amongst the painful TMDs, the highest prevalence was observed for masseter myalgia in group 2 (P = 0.031), and importantly group 4 did not differ from group 0 (P = 0.948). The MPQ score was significantly higher in group 1 (P = 0.001) compared to group 0, and the JFLS score was significantly higher in group 1, 2 and 3 compared to group 0. Notably MPQ (P = 0.756) and JFLS (P = 0.572) scores in group 4 were not different from group 0. However, MVBF (P = 0.996) and ME (P = 0.991) did not differ between groups 1 and 4. Association of self-reported pain and jaw function with masticatory function was observed in OS patients. CONCLUSION OS was not associated with a negative impact on TMD. Jaw function and pain levels were similar to controls at the 24-month follow-up. Masticatory function was further affected by the surgery and seems to require a longer recovery time. Moreover, it was confirmed that pain and TMD were associated with limitations in jaw function and impacts on masticatory function.