正常年轻成年人正面像上下颌角点的分布规律和定位方法

目的:观察正常年轻成年人标准化正面像上下颌角点(Go)的位置分布规律,提出一条新的面部参考线和下颌角点定位方法,为研究正畸治疗对面部软组织正面观的影响提供依据。方法:筛选108名正常年轻成年人,在自然头位下拍摄标准正面像A和标记双侧Go的正面像B。以颧弓点-颏下点连线(Zy-Me)作为新面部参考线,观察下颌角点相对于Zy-Me参考线的位置分布规律;比较面宽/下颌宽指数(Zy-Zy/Go-Go)真实值与计算值之间的差异,检验新定点方法的正确性;比较不同性别研究对象Zy-H/Zy-Me和Zy-Zy/Go-Go的差异。结果:过Go向Zy-Me连线作垂线,垂足位置的频数分布呈现以近似Zy-Me线段中点(50.31±2.21)为均值的正态分布(Normality=0.990);Zy-Zy/Go-Go真实值与计算值间比较差异无统计学意义(P>0.05,Cronbach's α相关系数>0.9);不同性别研究对象Zy-H/Zy-Me和Zy-Zy/Go-Go比较差异均无统计学意义(P>0.05)。结论:在正常年轻成年人正面像上,Go相对于Zy-Me的投影点接近线段中点;将过Zy-Me连线中点的垂线与面部轮廓交点作为正面像上的Go这一定位方法值得临床应用。

Distribution and locating method of gonion on frontal photograph of normal young adults

Objective To observe the distribution of gonion (Go) on the frontal photograph of the normal young adult,and to hypothesize a new facial reference line for locating gonion,and to provide the basis for studing the effect of orthodontic treatment on the frontal view of facial soft tissue.Methods 108 normal young adults were selected. Each subject was taken two frontal photographs under natural head position,such as a standardized one (A) and the other one with marked Go by facebow (B). The Zy-Me segment was used as a new reference line and the distribution of Go towards the Zy-Me segment was observed. The true value and calculated value of Zy-Zy/Go-Go were compared to prove the validity of the new method. The differences of Zy-Me and Zy-Zy/Go-Go between different genders were also analyzed.Results By making a perpendicular towards the Zy-Me segment via Go,it showed that the feet were located near the midpoint of the segment (50.31±2.21). The distribution of the frequency of Zy-H/Zy-Me followed the normal distribution (Normality=0.990). There were no significant differences between the true values and the calculated values of Zy-Zy/Go-Go (P>0.05, Cronbach's α coefficient > 0.9). There were no significant differences of Zy-H/Zy-Me and Zy-Zy/Go-Go of the objects between different genders(P>0.05).Conclusion On the frontal photograph of the normal young adults,the projected point of Go locates near the midpoint of the Zy-Me segment. The intersection of the facial contour and the perpendicular towards the midpoint of Zy-Me segment can be seen as Go in clinical trials.