The lateral cavity of the incisor can be repaired, we call the lateral cavity as the adjacent cavity, which is more complicated to repair than the cavity of the complete joint, but it can be repaired with the same material. If the lateral cavity is shallow and does not invade the pulp, the lateral cavity can be thoroughly prepared by using turbo drill to remove the decayed part, and if necessary, the retention of dove tail or inverted concave can be designed, and then the cavity can be filled with filling material. When filling the lateral cavity, we can apply the adjacent surface molding system to make the adjacent surface of the tooth into a better shape, and the effect of filling is relatively good.