咬合与髁状突形态的对称性间的相关关系解剖学

目的：探讨髁状突形态对称性与咬合对称性的关系及其意义。方法：观察32具颅骨的咬合关系，并根据是否存在产生不对称的非轴向咬合力的咬合关系而将其分为咬合对称组（17例）、咬合轻度不对称组（6例）和咬合明显不对称组（9例），其中主要包括以下几种咬合；①第三磨牙伸长；②因后牙缺失久未修复而导致的邻牙倾斜、对颌牙伸长的继发性错He；③后牙反He或锁He。髁状突形态对称性也分为对称（12例0、轻度不对称（15例）和明显不对称（5例），并用游标卡尺（精度0．02mm)测量其内外径和前后径。结果：①咬合对称程度与双侧髁状突对称程度有密切关系，即咬合对称者，双侧髁状突对称的比例比较高，咬合不对称者，其髁状突也多不对称；②髁状突大小的差异，主要表现为内外径的差异，可能系样本的问题，前后径差异未达到统计学显著水平；③咬合正常者，双侧髁状突形态不仅基本对称，而且其12侧髁状突的形态也基本一致。结论：咬合对称性与双侧髁状突形态对称性存在一定的相关关系，髁状突不对称的显著表现是内外径明显差异。此特点可能是咬俣异常易导致颞下颌关节紊乱症的解剖学基础。

An anatomic study on therelationship between occlusion symmetry and condyle symmetry

Objective: To investigate the anatomic relationship between occlusion and condyle.Methods: 32 skulls with their occlusion preserved well were studied. The occlusion was classified as symmetry（17 cases），mild asymmetry（6 cases） and severe asymmetry（9 cases）according to whether the occlusion force could be directed along the long axis of the posterior tooth or at an angle to it including the hyper erupted third molar, the secondary malocclusion caused by loss of posterior teeth without repairing for a long time , resulting in hyper eruption of opposite teeth and inclination of the neighbors and cross-bite of posterior teeth. The condyle form was classified as symmetry （12 cases），mild asymmetry（15 cases） and severe asymmetry（5 cases）and its dimensions of lateral-medial and anterior-posterior were measured with a vernier (precise 0.02 mm).Results：Close relationship between occlusion symmetry and condyle shape symmetry was observed. The difference between bilateral condyles was found in the lateral-medial dimension. The bilateral condyles from the 6 cases with normal occlusion showed symmetry and quite similar form. Conclusion: There is a close anatomic relationship between occlusion symmetry and condyle symmetry. The main difference of the bilateral condyle without symmetry is the lateral-medial dimension. That might be the anatomic basis for the TMD caused by abnormal occlusion.