Evaluation and treatment program for the rehabilitation of mastication of patients who underwent orthognathic surgery for dentofacial deformity

INTRODUCTION: Individuals with dentofacial abnormalities present facial alteration - in the vertical and/or anterior posterior plane -, with consequent unstable occlusion and poor dental intercuspation. These alterations can cause impairments in the functions of the orofacial myofunctional system, and functional adaptations are usually observed for each type of deformity. The aim of this thesis was to conduct a randomized clinical trial that the relevance variable was the functional response of the mastication after the rehabilitative experimental program in patients submitted to orthognathic surgery. METHODS: All patients underwent to the orthognathic surgery, in a period of 12 months, which agreed to participate of this study. Patients were randomized assigned into two groups: experimental group (EG = 6) and group instruction (GI = 5). A control group consisted of individuals with normal dental occlusion (CG = 6). The EG patients underwent a structured treatment protocol, in six sessions, with technical focus was on the function of mastication. Patients in the IG were submitted to two supervised sessions for instruction related to the look out of mastication (standard treatment). The variables adopted for the comparison groups were obtained by clinical evaluation and by assessment of surface electromyography (sEMG) that was: orofacial mobility, masticatory/deglutition clinical performance, jaw movements and muscle activation (electrical activity) of the masticatory muscles. These parameters were evaluated pre-and postoperative long-term (12 months). The subjects in the CG were also tested in two distinct moments, with a one year interval. RESULTS: One year after orthognathic surgery, EG showed a significant improvement in orofacial mobility (p=0.001), masticatory/deglutition clinical performance (p=0.001), jaw lateralization (p=0.001) and jaw protrusion (p=0.011). Both groups of patients presented no significant differences for the sEMG results. The CG presented no significant variations in performance for any of the investigated variables when comparing the different time points. CONCLUSION: The results suggest that the rehabilitative experimental program demonstrated a positive result. No adverse effects were identified. There was adherence to the treatment. The sample size, although relevant to the area, requires careful about the power of generalization of the results.