Many tooth cleansing instruments and agents have been developed for removal of plaque, inhibition of plaque formation and reduction of gingival inflammation. The aim of this study was to evaluate the plaque control effect and the therapeutic effect of newly developed tooth cleansing instrument(Belloblanco(R)). 40 healthy subjects with gingivitis or early periodontitis were divided into two groups. Subjects in control group only used manual tooth brushing and in experimental group used manual tooth brush and additive tooth cleansing instrument(Belloblanco(R)). Additive tooth cleansing instrument was used once a week. At baseline scaling and tooth brushing instruction was performed. Probing depth, bleeding on probing, plaque index, gingival index were scored at baseline, 2weeks, 4weeks. Probing depth of control and experimental group were significantly reduced at 2 weeks, 4weeks, hut there were no differences between two groups(P<(0.05). Bleeding on probing, plaque index and gingival index of control and experimental group were significantly reduced at 2weeks and 4weeks and there was significantly more reduction in the experimental group than the experimental group than the control group(p<(0.05). From these finding. it can be conclude that newly developed tooth cleansing instrument(Belloblanco(R)) are effective on the removal of plaque and the reduction of gingival inflammation