In cultured primordia, molar and incisor tooth germs can easily be distinguished by their appearance and their gene activity, although other shapes found in the human mouth, such as premolars and canines, are more difficult.

• 在组织培养的牙齿原基里头，可以从外观和基因的活性，轻易分辨出臼齿与门齿的牙胚，不过，人类口腔里的其他牙齿，像是前臼齿与犬齿，就比较难以区分。