骨性III类错畸形患者正颌手术前后下颌运动轨迹变化的初步研究

目的:应用下颌运动轨迹仪评价骨性III类错牙合畸形患者正颌手术前后下颌运动的变化。方法:对15例骨性III类错牙合畸形需正颌手术病例和20例正常牙合对照组,采用ARCUSDigma下颌运动轨迹仪测定受试者最大开口运动,前伸及左右侧边缘运动距离,记录由计算机通过切牙运动模拟的双侧髁突的运动轨迹间的最大差数(MRC)。通过自身比较以及与对照组比较,评价患者在术前、术后3个月及6个月时下颌运动的变化以及髁突运动的对称性。采用团体t检验和配对t检验进行统计学处理。结果:术前患者除开口度外,其他运动距离均小于对照组,前伸运动差异显著(P<0.05);开口时MRC值大于对照组(P<0.05)。术后3个月时,开口度及左侧运动距离下降,前伸和右侧运动略有增加;MRC呈上升趋势。术后6个月时,下颌运动距离均有所增加,除开口度外其余均超过术前水平,与对照组无统计学差异;MRC小于术前水平且与对照组差异无显著性。结论:骨性III类错牙合畸形患者下颌运动水平与正常牙合存在差异,髁突运动对称性较差。正颌手术能够有效地改善患者的下颌运动功能。

A primary study of mandibular kinesiogram on skeletal Class III malocclusal patients before and after orthognathic surgery

PURPOSE: To evaluate the functional change of mandibular movement on skeletal Class III malocclusal patients before and after orthognathic surgery with control group. METHODS: Mandibular movements of 15 skeletal Class III malocclusal patients and 20 controls were investigated by mandibular kinesiograph (ARCUSDigma, KAVO). Centric maximum mouth opening(MMO), protrusive and laterotrusive movements were measured and the same procedure was performed by 3 months and 6 months postoperatively on patient group. Distances of mandibular movements and maximum remainder of bilateral condylar movements(MRC) were analyzed by means of Student's t test. RESULTS: A significant difference was found in protrusive movements between patient group and control group(P<0.05), however the MMO was larger than the control group. MRC of patients was larger than the control group and the statistical difference was found in centric mouth opening movements(P<0.05). Hypomobility occurred in MMO and left laterotrusive movement 3 months postoperatively. Protrusive movements were improved and MRC increased by 3 months postoperatively.Mandibular movements were improved by 6 months postoperatively, statistical differences were not found in the protrusive and laterotrusive movements and MRC value between patient group and control group which demonstrated that the mandibular movement function was improved after orthognathic surgery. CONCLUSION: Mandibular movements of skeletal Class III malocclusal patients were different from the control group. Orthognathic surgery has favorable effects on the function of mandibular movements.