If the filling material falls off, that is, the filling body falls off, if it is caused by the defect of cavity preparation, it is necessary to grind the teeth again to prepare the cavity, if it is caused by the modulation of filling material or improper filling method, it is not necessary to grind the teeth again, as follows. 1. Need to grind the teeth again: The filling is lost due to poor resistance or retention of the cavity, such as the cavity is too shallow, the bottom of the cavity is not flat, the angle of the axial pulp line is too blunt or too sharp, etc., so it is necessary to re-prepare the shape of the cavity and grind the teeth again. 2. No need for re-grinding: If the filling is lost due to improper proportion of filling materials, lack of strict moisture barrier during filling, insufficient filling pressure, insufficient acid etching, etc., remove the residual filling and adhesive and re-fill the filling. There may be other reasons for filling loss, so it is recommended to go to the hospital and receive regular treatment.