Toothbrushing is the most widely recommended and practiced method of dental home care. While there is considerable information available in the literature on the time spent brushing the teeth, there is minimal information relating actual brushing time with the time patients estimate they normally brush. This paper reports in detail a study conducted in Switzerland in the 1980's, and supplements this information using the same protocol with two different Swiss populations conducted in the 1990's. In the early Swiss study, on volunteers registering at a dental clinic, the mean actual toothbrushing time was approximately 68 seconds. In the two recent studies, conducted with Swiss army soldiers or three groups of inhabitants in a town near Zurich, the actual toothbrushing means were 83.5 and 72.8 seconds, respectively. In the three studies conducted, the time subjects estimated they had brushed ranged between 134.1 to 148.1 seconds. In all studies, the difference between actual and estimated times was significantly different (p < 0.01). The amount of toothpaste used during toothbrushing was evaluated in two of the studies. In both evaluations, the amount of dentifrice used was approximately 1 gram. Dental professionals should be aware that there is a consistent difference in the time that patients believe they brush, and the time they actually spend brushing.