单侧第三磨牙伸长对下颌边缘运动轨迹的影响

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

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。

Objective To investigate the effect of unilateral hyper-erupted third molar on the mandibular border movements. Methods Adopted ARCUSdigma lI mandibular movements tracing instrument, with 56 unilateral by- per-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 〈 O. 01 ）. （~ 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.