Childhood Toothbrushing Reduces Adolescent Caries in Advantaged but Not Disadvantaged Areas: Australian Cohort Evidence — The Association Specialists
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  3. Childhood Toothbrushing Reduces Adolescent Caries in Advantaged but Not Disadvantaged Areas: Australian Cohort Evidence

Childhood Toothbrushing Reduces Adolescent Caries in Advantaged but Not Disadvantaged Areas: Australian Cohort Evidence (23600)

Hesham Al-Sharani 1 , Nicole Stormon 2 , Alice Richardson 1 , Yuehan Zhang 1 , Tehzeeb Zulfiqar 1
  1. National Centre for Epidemiology and Population Health, Australian National University, Acton, Australian Capital Territory, Australia
  2. Oral health , University of Queensland, Brisbane, Queensland, Australia

Background Dental caries disproportionately affects socioeconomically disadvantaged children. Clinical guidelines recommend twice-daily toothbrushing from early childhood, yet whether this behaviour confers equal protection across social strata remains unclear. If structural barriers attenuate the benefit of individual preventive behaviour in disadvantaged populations, behavioural interventions alone may be insufficient to reduce oral health inequities. This study examined whether the association between early toothbrushing and adolescent caries differed by area-level socioeconomic position.

Methods Data were from a nationally representative Australian birth cohort (N = 2,999 with complete data; 12-year follow-up). The exposure was carer-reported twice-daily toothbrushing at age 2–3 years. The outcome was dental caries by age 14–15. Effect modification by area-level socioeconomic position (SEIFA Index of Relative Disadvantage, dichotomised) was assessed via multiplicative interaction terms and stratified multivariable logistic regression, adjusting for parental education, household structure, geographic remoteness, dietary behaviours, and maternal smoking. Absolute risk differences were estimated via g-computation.

Results Caries prevalence was higher in disadvantaged areas (59.3% vs 51.1%) despite virtually identical brushing rates (46.7% vs 45.8%). Overall, twice-daily brushing was associated with lower caries odds (aOR = 0.75; 95% CI: 0.65–0.87; risk difference = −7.0 percentage points). A significant interaction by area-level disadvantage was detected (p = 0.048): in non-disadvantaged areas, the association was strong (aOR = 0.68; risk difference = −9.5 pp, p < 0.001), but in disadvantaged areas it was attenuated and non-significant (aOR = 0.92; risk difference = −2.1 pp, p = 0.49). Results were robust to inverse probability of censoring reweighting (interaction p = 0.028).

Conclusion Early toothbrushing was protective overall but yielded substantially smaller benefits in disadvantaged areas, despite similar brushing prevalence. These findings suggest that structural determinants constrain the effectiveness of individual preventive behaviour, highlighting the need for complementary structural interventions to reduce oral health inequities.