Changes in masticatory functions after surgical orthognathic treatment in patients with jaw deformities: Efficacy of masticatory exercise using chewing gum

Abstract

Changes in masticatory functions after surgical orthognathic treatment were evaluated longitudinally in 47 patients in whom mandibular prognathism were surgically corrected and the efficacy of masticatory exercise for the masticatory functions was evaluated. The masticatory exercise group consisted of 34 subjects and the control group consisted of 13 subjects without masticatory exercise and the normal occlusion group consisted of 20 subjects. Masticatory exercise using chewing gum was started at 6 months after surgery and was conducted for 5min two times a day for 90 days. Masticatory efficiency was measured using ATP granules, and the number and area of occlusal contacts and maximal occlusal force were measured using a computerized system consisting of pressure sensitive sheets.The mean values of all measurements before surgery in the patients were significantly lower than those in the normal occlusion group and the values increased gradually after surgery, especially in the masticatory exercise group, but the final values were still low compared with those of the normal occlusion group. The mean of executing rates of masticatory exercise in the masticatory exercise group was 68.6%. Positive correlations were found between executing rates of masticatory exercise and improvement rates in masticatory efficiency and maximal occlusal force. We conclude that masticatory exercise using chewing gum after orthognathic surgery is effective for improving masticatory efficiency and maximal occlusal force in patients with jaw deformities.