Background and objective: 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.Methods: 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), 24month 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-coloured chewing gum. Data were analysed using structural equation modelling. Results:The prevalence of non-painful TMD did not differ between groups (p = .827).However, the prevalence of painful TMD differed between groups (p = .001). Among the painful TMDs, the highest prevalence was observed for masseter myalgia in group 2 (p = .031), and importantly group 4 did not differ from group 0 (p = .948). The MPQ score was significantly higher in group 1 (p = .001) compared to group 0, and the JFLS score was significantly higher in groups 1, 2 and 3 compared to group 0. Notably, | 747MADHAN et al.

Objectives To assess the intraexaminer and interexaminer reliabilities of novel semiautomatic methods to segment the nasal cavity (NC) and pharyngeal airway (PA) and to determine the minimal cross-sectional area (CS) and hydraulic diameter (HD) of the PA. Materials and Methods To test reproducibility, two examiners analyzed the NC and PA independently in 10 retrospectively selected cone beam computed tomography (CBCT) images using semiautomatic segmentation. The PA centerline was determined to assess the minimal CS and HD. The intraclass correlation coefficient (ICC) was used to calculate intraexaminer and interexaminer reliabilities. Measurement errors were assessed by Dahlberg's formula and paired t-tests. The level of agreement was assessed using the Bland-Altman method. Results Intraexaminer and interexaminer reliabilities were excellent (minimal ICC, 0.960). The error of the method was good except for interexaminer values for the oropharynx (P = .016). The minimal CS and HD measurements were reliable (minimal ICC, 0.993; narrow limits of agreement). Conclusions The novel methods for analysis of the NC and PA are reliable. The minimal CS and HD demonstrated excellent reliabilities, which are critical to detect the most constricted part of the PA. Separation of the oropharynx from the voids close to the retroglossal area is not trivial and should be considered with caution.

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