Purpose: To compare the interdental plaque removal capacity of dental floss, a cylindrical and a conical interdental brushes. Material and Methods: Fifty individuals were selected from those attending a maintenance programme for periodontally treated patients. Upon written agreement, the Silness and Löe Plaque Index (Pl.I) was registered in nine interdental spaces in three quadrants. The patients were then instructed on the use of each device and performed the cleaning until they felt it was satisfactory using one instrument for each quadrant. The same calibrated examiner registered Pl.I again, unaware of the instruments used in each quadrant. Mean values were calculated and compared by One Way ANOVA + Bonferroni and paired sample t test (α=.05). Frequency distribution of scores 0+1 and 2+3 was also calculated and compared by Mc Nemar. Results: The mean Pl.I at start was 1.71 for dental floss, 1.69 for the conical and 1.66 for the cylindric interdental brushes. All three instruments reduced plaque significantly. Thus, the final mean Pl.I was 1.02, 0.46 and 0.42 for floss, conical and cylindric brushes, respectively. The final values observed for the interdental brushes were significantly smaller than those observed for floss. The same result was observed for the frequencies of 0+1 and 2+3 criteria of the Pl.I. Conclusion: It may be concluded that, for individuals in periodontal maintenance care, interdental toothbrushes, regardless of their shape (conical or cylindric) are more efficacious in interdental supragingival plaque removal than dental floss. Keywords: dental floss, efficacy, interdental brush, supragingival plaque control