1949年Neff[1]首先提出了上下前牙牙冠宽度比即“前牙系数”的概念,并认为此系数应介于1.20~1.22之间,才能保证让前牙达到理想的覆牙合、覆盖。Bolton通过研究发现上下颌牙冠宽度比例协调是建立良好咬合关系的必要条件,这个比率被称为“Bolton指数”[2]。Bolton指数的提出,受到 In 1949, Neff [1] first proposed the concept of crown width ratio of upper and lower anterior teeth, “anterior teeth coefficient”, and considered that this coefficient should be between 1.20 and 1.22 to ensure that the anterior teeth reach the ideal overbite and cover . Bolton found through the study that the mandibular crowns width ratio coordination is a necessary condition to establish a good occlusal relationship, this ratio is called “Bolton index” [2]. Bolton index raised by