Due to the different degree of mineralization of enamel and dentin tissues, tooth decay will present the characteristics of small mouth and big bottom, found that need to remove the decay immediately after resin filling. 1. Tooth decay general enamel after the emergence of small caries, remove the surface of the decay, can be found in the dentin layer, caries is more serious than the enamel layer, found that dental caries need to go to the hospital immediately after the use of specialized instruments to remove the decay of the dental tissues, the use of composite resin filling to stop the caries to continue to develop. 2. If the decayed tooth tissue has penetrated the pulp cavity after removing the decayed tooth tissue, it is necessary to carry out root canal treatment before filling. If dental caries is found, it needs to be treated immediately to avoid pulpal inflammation.