Extra teeth, also known as extra teeth, are extra teeth that are within the normal range of teeth. Normally, there are 20 milk teeth, namely 8 milk incisors, 4 milk cuspids and 8 milk molars. There are 28-32 permanent teeth, namely, 8 permanent incisors, 4 permanent cuspids, 8 permanent premolars, and 8-12 molars. Multiple teeth generally occur in the permanent dentition and are commonly found between the maxillary central incisors. The reason for the occurrence of multiple teeth is still unclear and may be due to some problems in the development of the dental embryo.