The amount of plaque accumulation was assessed in an intraindividual study comprising 10 individuals. During different 2-week periods, the test subjects used nylon floss (unwaxed, waxed and specially treated), silk floss (unwaxed and waxed), Superfloss or triangular toothpicks for interdental tooth cleaning. Only teeth in contact with neighboring ones and with open interdental spaces were included in the study. The plaque removal of the interdental aids used was registered by estimating the amount of plaque present at the end of each experimental period according to a Plaque Index (Silness & Löe 1964) modified for plaque registration on 10 surface units around each tooth. In general, dental floss had a higher plaque removing potential than triangular toothpicks, especially on lingual axial surfaces.