The Effects of Chewing Exercises on Masticatory Function after Surgical Orthodontic Treatment

Recovery of oral function is one of the most important objectives of orthognathic surgery. This study investigated the effects of a chewing exercise on chewing patterns and other oral functions after sagittal split ramus osteotomy (SSRO). Ten subjects performed a chewing exercise. The control group comprised 19 patients. For masticatory function, the masticatory pattern, width, and height were assessed. For oral function, the occlusal, lip closure, and tongue pressure forces were measured. The chewing exercise was started 3 months after SSRO, and was performed for 5 min twice a day for 3 months. The masticatory pattern normalized in 60% of the patients and remained unchanged for the reversed and crossover types in 40% of the patients. In contrast, 21.0% of patients in the control group showed a change to the normal type. This may be a natural adaptation due to the changes in morphology. A more detailed study is needed to determine what does and does not improve with chewing exercise. The masticatory width significantly increased after performing the exercise. For oral function, a significant increase in the occlusal force was observed, with no significant difference in the control group. Chewing exercises immediately after SSRO improve masticatory patterns.