A 5-week training period with repeated hands-on instruction gives panellists the skill to perform brushing with efficacy comparable to that of professional brushing. In agreement with a previous study, the 3D was more effective than a flat-trimmed manual toothbrush (Van der Weijden et al. 1994). Brushing with the criss-cross resulted in small statistical differences with the 3D and the flat-trimmed manual toothbrush. The clinical relevance of these statistically significant results should be the subject of a longitudinal study.