下顎後退術後の舌圧と後戻りについて

Abstract

Various surgical orthodontic procedures are currently employed for the correction of jaw deformities.A postoperative problem, relapse, seems to be due to an imbalance of the perioral muscular groups resulting from changes in the cavitas oris propria after surgery. Among other factors, it is widely known that the effect of the tongue, i.e., tongue pressure, is greatly involved in such relapse, but no detailed reports on this matter have been available.In the present study, in 15 patients who underwent retropositioning of the mandible by sagittal splitting osteotomy or mandibular body step-ostectomy, the tongue pressure during deglutition of saliva and water and during maximal anterior position were determined before and after surgery.In addition, changes in tongue pressure during various movements were analyzed in combination with standerd X-ray films of the head taken during those movements. The relation of tongue pressure to changes in the jaw before and after retropositioning of the mandible was thus investigated by comparing the two surgical methods, and the folowing findings were obtained.1. Tongue pressure tended to increase both after sagittal splitting osteotomy and mandibular body step-ostectomy.2. In patients who underwent sagittal splitting osteotomy, tongue pressure tended to increase gradually from 3 to 12 months after surgery, the mandibular position changing in a forward direction from 6 to 12 months along with the increase.In Patients with mandibular body stepostectomy, tongue pressure was not markedly altered from 3 months after surgery, the mandibular position also showing no marked changes from 3 months after surgery.3. These changes in tongue pressue, however, varied in different individuals, and whether an increase in tongue pressure correlates with the degree of relapse remains to be clarified.