Abstract
A literature review was performed concerning the changes of orthognathic functions, especially of the lip, tongue and masticatory muscle functions, by the treatment of dentofacial deformity. Improvement of maxillofacial morphology by surgical orthodontic treatment results in normalization of the resting and functional behaviors of the lip and tongue, and the lip pressure during rest and function decreases. No significant correlation has been reported among the changes in tongue pressure and amount of surgical correction and relapse. The importance of tongue posture associated with respiration is suggested.
In patients with dentofacial deformity, the masticatory muscle function was impaired before surgery, and also immediately after surgery. Muscle atrophy and functional deterioration due to surgical invasion and intermaxillary fixation occur. After six months, functional recovery gradually occurred, and it reached that of the control group at 4 years or more. It is suggested that improvement of occlusion brings about this change and that the adaptation of masticatory muscle may differ depending on maxillofacial morphology. Although the effectiveness of masticatory muscle training is advocated, further research is required.
