Is the masticatory function changed in patients with temporomandibular disorder?

Patients with temporomandibular disorders (TMD) often complain and have limitation in masticatory function, which can be affected by a complex interaction of factors. The aim of this study was analyze the masticatory function in patients with TMD using surface electromyography (EMG) and masticatory efficiency (ME). Twenty-seven patients with TMD and 25 considered control (n), aged between 18 and 60 years, paired by age and gender, were evaluated according to RDC/TMD. In both groups were performed: EMG with chewing gum, clinical evaluation of habitual chewing with stuffed cookie (CE) (number of chewing strokes and time) and analysis of ME with fuchsin beads. Nonparametric statistical analyses were used (Mann-Whitney) for comparisons between groups, with 5% significance level. For all variables, the TMD group showed higher values than the control, with statistical significance for ME (p<0.0001), number of chewing strokes (p=0.04), chewing time (p=0.009), right masseter EMG activity (p=0.05), left masseter (p=0.005), right anterior temporal (p=0.05) and left anterior temporal (p=0.001). The conclusion is that patients with TMD showed changed chewing pattern, but without impairment of masticatory function.