OBJECTIVE This single blind, randomized clinical trial evaluated the relationship between frequency of mechanical removal of plaque (MRP) and gingival inflammation. METHODS Fifty-two patients (maximum 5% of sites with gingival bleeding and no history of periodontitis) were randomized to different frequencies of MRP: 12, 24, 48 and 72 h. Plaque index (PlI) and gingival index (GI) were evaluated at baseline, 15 and 30 days. Intra- and inter-group differences were determined by repeated measures anova and mixed models anova, respectively, both followed by Tukey's test. RESULTS The mean GI between baseline and 30 days remained statistically unchanged in the 12 h (0.51 ± 0.17 versus 0.63 ± 0.23, p = 0.137) and 24 h (0.43 ± 0.19 versus 0.59 ± 0.21, p = 0.052) groups, but increased significantly in the 48 h (0.48 ± 0.18 versus 0.84 ± 0.21, p = 0.001) and 72 h (0.55 ± 0.20 versus 0.94 ± 0.25, p = 0.000) groups. At 30 days, the average percentage of sites with GI scores of 1 and 2 was significantly higher in the 48 and 72 h than in the 12 and 24 h groups (p < 0.05). CONCLUSIONS Frequencies of mechanical removal plaque up to 24 h may prevent an increase in the severity of gingival inflammation over a period of 30 days in patients with no history of periodontitis.