一般认为畸形中央尖发生的原因是由于牙发育时期,牙乳突组织向造釉器突起,在此基础上形成牙釉质与牙本质,结果形成畸形中央尖。畸形中央尖常为对称性,但亦可单侧发生。该牙尖多见于下颌前磨牙(特别是下颌第二前磨牙),次为上颌前磨牙。畸形中央尖可发生在一个前磨牙上,也可发生在几个甚至全部前磨牙上。但后者是罕见的。现将本例报告如下: Generally believed that the deformity of the central apex occurs because of tooth development period, the organization of the teeth to the enamel process, on the basis of the formation of enamel and dentin, the results of the formation of deformity of the central tip. Deformity central tip often symmetry, but also unilateral. The cusp tip more common in mandibular premolar (especially mandibular second premolar), followed by maxillary premolar. Deformity of the central tip can occur in a premolar, can occur in a few or even all premolar. But the latter is rare. Now report this case as follows: