Unpredictable chaos or an individual stable habit - a correlational analysis of repeatedly assessed toothbrushing behavior

Effective tooth brushing is an important part of maintaining good oral health. Epidemiological data indicate that people have difficulties to achieve oral cleanliness when brushing their teeth. Various cross-sectional studies therefore observed people while brushing and found some widespread behavioral deficits like neglect of inner surfaces and inconsistent brushing movements. Yet, longitudinal studies are missing that explore, whether people show these deficits consistently over time. To clarify this, the intra-individual stability of tooth brushing performance was investigated by repeated observation of n = 105 students at two brushing appointments (T1/T2) two weeks apart. Half of them (n = 52) were instructed to brush to the best of their ability and the other half to brush as usual (n = 53). Calibrated observers analyzed brushing behavior with respect to brushing duration, brushing movements (horizontal, circular, vertical), brushing time on tooth surfaces (outer, inner, occlusal), and distribution of time across sextants. Correlational analyses revealed a high intra-individual stability of all parameters under both instructions. Correlation coefficients varied between r = 0.72 (horizontal movements at outer surfaces) and r = 0.93 (total tooth contact time). Results indicate that people develop very specific individual toothbrushing patterns. It is important that preventive measures take into account the challenge of changing such established habits. Healthcare professionals and patients alike need to recognize this challenge when addressing oral hygiene deficiencies.