Abstract: Objective:?Establishing an animal model which can simulate the natural tooth developing environment in physiological condition for the researches of tooth regeneration, root development and tooth eruption. Methods:?The upper first molar of mouse at bell stage is used in this model for extraction and transplantation, comparing with the subrenal capsule transplantation model by radiological and histological observation postoperatively. Results:?The tooth germ of upper first molar by the postnatal 8th day has almost formed the crown and the root development is about to begin, which is a suitable subject of study in this model. Comparing with that in the subrenal capsule transplantation model, the root development of transplanted tooth germ in this model shows more similar to that of the natural tooth. Conclusions:?The extraction and orthotopic transplantation model of the upper first molar at bell stage in mice is a desired option for the observation of root development and tooth eruption.

Key words: Tooth germ, animal model, tooth regeneration, Tooth development