Behavioural Determinants of Post-Brushing Dental Plaque Levels: A Video-Based Analysis

Toothbrushing remains the most widely practiced method for dental plaque removal. However, evidence-based guidance on optimal brushing method, duration, toothbrush bristle wear, and dentifrice quantity is still insufficient. This study aimed to identify behavioural factors associated with post-brushing dental plaque levels using video-based analysis of habitual toothbrushing.

Eighty-eight adults were recruited and recorded while brushing under habitual conditions. Toothbrushing behaviours (duration, motion, surface coverage, and multi-area brushing) were coded using behavioural analysis software (Mangold Interact). Toothbrush bristle wear was classified by the Conforti index and dentifrice quantity was recorded photographically. Dental plaque was assessed using the Turesky Modification Quigley-Hein Index (TMQHI). Data were analysed using independent t-tests, one-way ANOVA, and linear mixed model (LMM) with SPSS 26.0. Statistical significance was set at p < 0.05.

Area-specific brushing duration was the strongest factor associated with lower plaque scores. Sites brushed for ≥ 5 s showed significantly lower plaque index scores than those brushed for < 5 s. In the LMM adjusting for all measured covariates, only brushing duration and brushing area remained significant.

Among all measured variables, area-specific brushing duration was the factor most strongly associated with post-brushing plaque levels. To achieve effective plaque control, it is essential to distribute brushing time equitably across all tooth surfaces and to allocate a minimum of 5 s per area.