利用三维数字模型对16名大学生个别正常牙合下颌牙弓及基骨形态的测量比较

目的 利用三维数字化模型对山东地区个别正常牙合下颌牙弓及基骨形态进行测量,探讨两者间相关性,并建立本地区正常牙合临床冠中心(FA)点到WALA点间距离的正常值,以期为临床诊断治疗提供指导。 方法 获取16例山东地区个别正常牙合志愿者的下颌模型,在石膏模型上标定各牙位FA点及WALA点,进行扫描获得三维数字化模型,描述牙弓及基骨的形态,分析其相关性,建立本地区FA-WALA点间距离的正常值。 结果 每个牙位区域的FA点和WALA点均是散在的,不能用统一的曲线来描述,且磨牙区的离散程度较大。下颌牙弓宽度及形状与基骨弓存在高度相关性,尖牙区宽度相关性为r=0.700,磨牙区宽度相关性为r=0.805,尖牙区与磨牙区比值的相关性r=0.625。 山东地区个别正常牙合下颌从中切牙至第二磨牙FA点至WALA点间距离分别为(-1.53±0.92)mm、(-0.97±1.11)mm、(0.65±0.90)mm、(1.17±0.64 )mm、(2.13±0.93 )mm、(3.12±0.72 )mm、(3.55±0.54)mm。 结论 下颌牙弓弓形与基骨弓形是个性化的,不能用一种形状归纳而来。WALA嵴可以作为预测临床牙弓形状的参考。

Analysis of dental and basal arch forms of 16 individual normal occlusions using three-dimensional evaluation

Objective To investigate the relationship between dental and basal arch forms in individual normal occlusion, and to establish the normal value between the facial-axis(FA)point and Will Andrews and Larry Andrews(WALA)point in Shandong population. Methods A total of 16 individual normal occlusions were selected. The FA points and WALA points were marked on the plaster casts, which were then scanned to obtain the digital data. Curves of dental arch and basal arch forms were illustrated. The distance between the FA points and WALA points was measured. Results The FA and WALA curves were sporadic, which could not be described with same curve. The dispersion degree of the molar area was large. The correlation between the FA and the WALA points in the intercanine width (r=0.700), intermolar width (r=0.805), and intercanine width to intermolar width (r=0.625)were highly significant. In our sample, the mean value of the distance between the FA points and WALA points from central incisor to second molar were(-1.53±0.92)mm,(-0.97±1.11)mm,(0.65±0.90)mm,(1.17±0.64)mm,(2.13±0.93)mm,(3.12±0.72)mm, and(3.55±0.54)mm. Conclusion Both the FA and WALA point-derived arch forms are unique and can not be defined by a generalized shape. The WALA points can be a useful predictor of the dental arch form.