Supernumerary teeth in anterior molars of raccoon dogs

Among the 82 skull specimens (33 males, 28 females and 21 unknowns) in the 1 st Department of Oral Anatomy, Kyushu Dental College, of raccoon dogs (Nyctereutes Procyonoides Viverrinus TEMMINCK), nine supernumerary teeth were observed in six cases (2 males, 1 females and 3 unknowns).1. Supernumerary teeth were found in the maxilla in two cases with a total of three teeth and in the mandible in fivecases with six teeth. A greater number of incident occurred in the mandible.2.In a maxillary case, eruptions of two teeth at the third anterior molars region, side by side from the lingual to the buccal sides, were observed. The buccal one was regarded as being the probable supernumerary tooth. Another case showed an incident of symmetrycal eruptions at the first anterior molars region on eachside of the maxilla. In addition, a supernumerary tooth was also observed at the first molars region of the left mandible.3. All the mandible cases showed eruptions at the first anterior molars region, along the line of dentition. The tooth on the mesial side was smaller in each case and was regarded as being of the supernumerary tooth germ.4. Among the mandible cases, there was a case of symmetrical eruptions. Comparison between the right and left sides showed that more incidents occurred on the left side.5. Incident of supernumerary teeth is notsignificant phylogenetically and it is considered to occur due to division of the tooth germ. However, the fact that incident occur frequently at the first anterior molars region suggests instability at this region in connection with the tooth being in the process of reduction.