| Popis: |
We investigated the changes in lip and cheek movements involved in smiling, recorded before and after surgical orthodontic treatment for mandibular protrusion with mandibular deviation (MPD), and compared the obtained data with those of individuals with normal occlusion (NO). The study enrolled 8 individuals with NO and 8 patients with MPD who underwent surgical orthodontic treatment at the Matsumoto Dental University Hospital. The lip and cheek movements of individuals were analyzed three–dimensionally using stereo images, and their frontal and lateral craniofacial morphologies were assessed using posterior–anterior and lateral cephalograms. Pre–treatment assessment of lip movements in MPD patients showed that the corner of mouth (CM) on the non–deviated side exhibited a significant increase in upward move ment and decrease in lateral movement, as compared to the deviated side. However, the comparison of these results with those of individuals with NO revealed that the lateral and posterior movement of the CM on the non–deviated and deviated sides, respectively, was significantly lesser in patients with MPD than in individuals with NO. Post–treatment assessment of lip movements showed an increase in the lateral and the upward movement of the CM on the non–deviated and deviated side, respectively, indicating the successful correction of asymmetrical CM movement. However, the posterior movement in the CM on the deviated and non–deviated sides in the patients with MPD were significantly lesser than those in individuals with NO. Furthermore, a comparison of the absolute values of three–dimensional movements recorded between the center of the upper and lower lips revealed no significant difference in pre– and post–treatment movements. On the contrary, post–treatment movement of the center of the lower lip in the posterior direction was significantly lesser in patients with MDP than individuals with NO. The three–dimensional movement of the cheek did not show significant difference between the deviated and non–deviated sides before and after treatment. However, the anterior movement of the cheek on the non–deviated side in the individuals with MPD increased significantly after treatment. There were no significant differences in the three–dimensional movement of cheek among individuals with MPD, before and after treatment, and in the individuals with NO. In the present study, the asymmetrical three–dimensional movements of CM involved in smiling, between the deviated and non–deviated sides in the individuals with MPD, were corrected after surgical orthodontic treatment. However, the post–treatment movements in the individuals with MPD were different from those in individuals with NO. |
