Results: The positive expression of PCNA was mainly located in stratum intermedium cells and amleoblasts in the early stage, and weakened gradually during amelogenesis;

• 结果釉质形成早期，中间层细胞、成釉细胞均呈PCNA阳性表达，且两者在同期表达强弱程度上具有一致性，随着牙冠发育的完成，PCNA的表达减弱；