Morphological analysis of supernumerary teeth in CEBP/beta knock-out mice

Aims: Recently, relationships between CEBP/beta and hard tissue formation such as osteogenesis, chondrogenesis, and odontogenesis have been reported. Regarding osteogenesis, CEBP/beta regulates IGF1, Runx2, osteocalcin and Cdknlc. As for odontogenesis, CEBP/beta is associated with DSPP which influences differentiation of dentinoblasts. Here we report supernumerary teeth in mice with CEBP/beta deficiency, with an approach of morphological analysis. Materials and Methods: The maxilla and mandible of 12-week-old CEBP/beta deficient mice were examined with micro-CT and HE stain methods. Results: Under micro-CT, supernumerary teeth were identified in CEBP/beta deficient mice. The supernumerary teeth were located near the radicular area of upper incisors. Under microscopy, the supernumerary teeth located near upper incisors were also confirmed. The supernumerary teeth showed an evidence of dentine and pulp tissue. This implied to formation of normal dental tissues. Conclusions: Formation of supernumerary teeth was related to CEBP/beta mutation. Because the cause of formation of supernumerary teeth remained unclear, future investigation in mechanisms of CEBP/beta on tooth formation is indicated. In addition, succeeding studies into supernumerary teeth of humans are required