Effect of Brushing Time on Plaque Removal with Manual Toothbrushing

There is limited data on the effects of manual toothbrushing duration on hygiene efficiency.  Digital Plaque Image Analysis permits objective evaluations of antiplaque technologies.   Objective:  In this study we assessed the effects of hygiene time on brushing efficiency with a manual toothbrush.  Methods:  Seventeen subjects participated in cross over study comparing the following a.m. on-site brushing regimens:  I:  ad-lib brushing;  II:  supervised brushing 40 sec.;  III: supervised brushing 80 sec.; IV: supervised brushing 120 sec.;  V: subject-timed 40 sec..  Timed brushings were supervised ‘blind' viz. as subjects were instructed as they brushed when to stop.  All brushing was carried out with Crest™ Cavity Protection dentifrice and an Oral B manual toothbrush (P35).  Subjects presented on site with morning plaque before breakfast to carry out their assigned hygiene.   Pre-brush a.m;  post-brush a.m. plaque was evaluated using standardized UV imaging techniques as described previously (White et al. J Clin Dent 17:22-26(2006)).  Plaque coverage was compared by ANCOVA with Scheffe adjustment for multiple comparisons.  Results:  Pre-brush a.m. mean plaque levels ranged from 11.78-13.10 % tooth coverage with no statistically significant differences between regimens.  Post brushing plaque levels measured: I 4.42: II 5.44: III 3.42: IV 3.80:V 4.58.  Increases in manual timed brushing significantly increased brushing effectiveness beyond 40 seconds (III vs. II p=0.0011; IV vs. II p=0.0158).  There were no differences in ad lib, supervised timed 40 sec. or self managed timed 40 sec. brushing.  Conclusion:   Increases in manual brushing time beyond 40 sec. increased plaque removal efficiency from statistically significant 50 % to over 71 %.  Plaque removal does not seem to differ with patient timed or supervised timed hygiene.