单侧第三磨牙伸长对下颌边缘运动轨迹的影响

目的研究单侧第三磨牙伸长对下颌边缘运动轨迹的影响。方法采用ARCUSdigmaⅡ下颌运动轨迹描记仪,分别记录56例单侧第三磨牙伸长患者(上、下颌各28例)下颌边缘运动轨迹,并以28例正常牙合下颌边缘运动轨迹作为对照。结果①上颌第三磨牙伸长组(A组)向正常侧运动范围与对照组(C组)不同(P<0.01),且A组向伸长侧运动范围与正常侧比较差异有统计学意义(P<0.05);下颌第三磨牙伸长组(B组)前伸运动范围小于C组(P<0.01)。②髁突运动最大差数(MRC):A组在开口运动(前后向)、前伸运动(垂直向)与C组比较差异均有统计学意义(P<0.01);B组在前伸运动(前后向)与C组比较差异有统计学意义(P<0.01)。③C组切点运动轨迹较规则流畅;余两组则明显突兀,多呈台阶状,波动幅度较大。结论单侧第三磨牙伸长对切点边缘运动范围、运动轨迹特征、双侧髁突运动对称性均有明显影响。

The effect of unilateral hyper-erupted third molar on the mandibular border movements

Objective To investigate the effect of unilateral hyper-erupted third molar on the mandibular border movements.Methods Adopted ARCUSdigmaⅡmandibular movements tracing instrument,with 56 unilateral hyper-erupted third molars 28 cases upper(group A),28 cases lower jaw(group B),and 28 cases without hyper-erupted third molars(group C),the mandibular border movements were enrolled in this study.Results ① Lateral movements of normal sides in group A were different significantly with control group(P<0.01),and hyper-erupted sides were different with normal sides(P<0.05) in group A;protrusive movements in group B were less than that in control group(P<0.01).② Maximum remainder of bilateral condylar movements(MRC): opening movements(anterior-posterior),protrusive movements(vertical)in group A were different significantly with control group(P<0.01);protrusive movements(anterior-posterior) in group B were different with control group(P<0.01).③ Movements trail of incisor point was regular and profluent in control group,however,it was abrupt in test groups with large fluctuation.Conclusion Unilateral hyper-erupted third molar can affect range and feature in border movements of incisor point,also affect symmetry of condyles movements.