Abstract: Objective To compare the clinical effects between two methods for preventing the fracture of central cusp deformity on immature premolars.They were enamoplasty preventive resin restoration（or composite resin strengthening） technique and resin restoration after oneoff grinding and indirect or direct pulp capping respectively. Methods 20 child patients who had central cusp deformity on the premolars bilaterally were enrolled.Teeth whose central cusp had erupted but not reached the occlusal plane were divided into two groups randomly,enamoplasty preventive resin restoration group（namely resin strengthening group） and resin restoration after oneoff grinding and indirect or direct pulp capping group.Each group had 31 teeth.All the patients were followed up for one year. Results No tooth was found failed in the group of enamoplasty preventive resin restoration.Among the 31 teeth treated by oneoff grinding method,4 failed,and the success rate was 87.10%.There was no statistical difference between the two methods（P>0.05）. Conclusions Noticing abnormal central cusp early and applying enamoplasty preventive resin restoration to strengthen abnormal central cusp before the teeth reached the occlusal plane can effectively prevent the fracture of abnormal central cusp,and ensure normal development of tooth.