Objective:To investigate the relationship among the congenital hypodontia of mandibular incisor and malocclusion and the variation of medial distal dimension of mandibular canine.

探讨下颌恒切牙先天缺失情况,与牙颌畸形以及下尖牙近中径变化。

So this fetus presented seeral signs of trisomy 21, including the hypoplasia of the nasal bone, hypodontia, micrognathia, and hypospadias.

这，胎儿显示21三体若干征象：包括鼻骨发育不全、牙发育不全、小颌和尿道下裂。