A COMPARATIVE-STUDY OF ELECTRIC TOOTHBRUSHES FOR THE EFFECTIVENESS OFPLAQUE REMOVAL IN RELATION TO TOOTHBRUSHING DURATION - TIMERSTUDY

The purpose of the present study was to test the plaque-removing effic acy of 4 different toothbrushes in relation to duration of toothbrushi ng. The brushes studied were a manual toothbrush (M), a conventional e lectric toothbrush - the Blend-a-Dent(R) (BL), the Interplak(R) (IP) a nd the Braun Plak Control(R) (BPC). For this study, 20 subjects were s elected. The study was divided into 5 experiments which differed only in respect to the brushing time. The available time in experiment 1 th rough 5 was 7.5, 15, 30, 45, 90 s per quadrant respectively. Prior to each experiment, all subjects were asked to abstain from oral hygiene procedures for at least 24 h. The efficacy of toothbrushing in each ex periment was studied while one investigator (MAL) brushed the teeth of the subjects. In each subject, all 4 brushes were tested. Each brush was assigned to a quadrant in a random order. No toothpaste was used t hroughout this study. The amount of dental plaque was evaluated before and after brushing by means of the Silness & Loe plaque index at 6 si tes around each tooth investigated, The results show an increase in ef ficacy for all brushes varying from 7.5 s per quadrant to 90 s per qua drant (mean plaque reduction in terms of percentage 7.5 s-90 s: M = 40 0/,75%, BL = 45%-82%, BPC = 51%-94%, IP = 64%-92%). The IP removed sig nificantly more plaque than the other 3 after 7.5 s of brushing. From 15 s through 90 s, the IP and BPC were equally effective. Both were, a t all times, significantly more effective than the M and BL. This diff erence was mainly caused by a greater plaque removal from the interpro ximal areas, since brushing for 30 s or more with all 4 brushes remove d about 90% of the plaque from the vestibular and lingual surfaces. Ev aluation of the efficacy in relation to brushing time showed for all b rushes that the greater part of the effect is reached after 30 s of br ushing per quadrant. The brushing time appears to be an important vari able in the evaluation of plaque removing effectiveness since the effi cacy increases with time and differs per toothbrush.