Full-mouth debridement and cleaning of dental biofilm are required for removal of the pathogens associated with periodontal disease. Then, smoothing of the dentin root surfaces (root planing) that have lost periodontal attachment is the most effective method to stop inflammation and recover the periodontal attachment. These procedures are currently performed using steel curette-type scalers with a cutting edge. However, the direction of curettage must be restricted when the tip of the scaler is manipulated in a periodontal pocket that contains pathogenic biofilm. The authors have developed a file-type scaler electroplated with diamond abrasive to the tip. This scaler can be manipulated in arbitrary directions for curettage. In this study, the curettage performance of the electroplated diamond scaler was evaluated in comparison with the standard curette style scaler.