High Plaque Levels after Thorough Toothbrushing: What Impedes Efficacy?

Previous studies have shown high levels of dental plaque after toothbrushing and poor toothbrushing performance. There is a lack of evidence about what oral hygiene behavior predicts persistent plaque. The present cross-sectional study thus relates toothbrushing behavior to oral cleanliness after brushing and to gingivitis.

All young adults from a central town in Germany who turned 18 y old in the year prior to the examination were invited to participate in the study. They were asked to clean their teeth to their best abilities while being filmed. Videos were analyzed regarding brushing movements (vertical, circular, horizontal, modified Bass technique) and evenness of distribution of brushing time across vestibular (labial/buccal) and palatinal (lingual/palatinal) surfaces. Dental status, gingival bleeding, and oral cleanliness after oral hygiene were assessed.

Ninety-eight young adults participated in the study. Gingival margins showed persistent plaque at 69.48% ± 12.31% sites (mean ± SD) after participants brushed to their best abilities. Regression analyses with the brushing movements and evenness of distribution of brushing time as predictors explained 15.2% (adjusted R² = 0.152, P = 0.001) of the variance in marginal plaque and 19.4% (adjusted R² = 0.194, P < 0.001) of the variance in bleeding. Evenness of distribution of brushing time was the most important behavioral predictor.

Even when asked to perform optimal oral hygiene, young German adults distributed their brushing time across surfaces unevenly. Compared with brushing movements, this factor turned out to be of more significance when explaining the variance of plaque and bleeding.

Results of this study can help clinicians and patients understand the meaning of specific behavioral aspects of toothbrushing for oral cleanliness and oral health.