Behaviour change intervention for toothbrushing (lesson and text messages) to prevent dental caries in secondary...

This multicentre, assessor-blinded, two-arm cluster randomized trial evaluated the clinical and cost-effectiveness of a behaviour change intervention promoting toothbrushing for preventing dental caries in UK secondary schools.

Pupils aged 11-13 years with their own mobile telephone attending secondary schools with above average free school meals eligibility were randomized (at year-group level) to receive a lesson and twice-daily text messages or to usual care. Year-groups (n = 84) from 42 schools including 4680 pupils (intervention, n = 2262; control, n = 2418) were randomized.

In 2383 participants with valid data at baseline and 2.5 years, the primary outcome of presence of at least one treated or untreated carious lesion (D_4-6 MFT [Decayed, Missing and Filled Teeth] in permanent teeth using International Caries Detection and Assessment System) was 44.6% in the intervention group and 43.0% in control (odds ratio [OR] 1.04, 95% CI 0.85-1.26, p = .72). There were no statistically significant differences in secondary outcomes of presence of at least one treated or untreated carious lesion (D_1-6 MFT), number of D_4-6 MFT and D_1-6 MFT, plaque and bleeding scores or health-related- (Child Health Utility 9D) or oral health-related- quality of life (CARIES-QC). However, twice-daily toothbrushing, reported by 77.6% of pupils at baseline, increased at 6 months (intervention, 86.9%; control, 83.0%; OR 1.30, 95% CI 1.03-1.63, p = .03), but returned to no difference at 2.5 years (intervention, 81.0%; control, 79.9%; OR 1.05, 95% CI 0.84-1.30, p = .69). Estimated incremental costs and quality-adjusted life-years (QALYs) of the intervention, relative to control, were £1.02 (95% CI -1.29 to 3.23) and -0.003 (95% CI -0.009 to 0.002), respectively, with a 7% chance of being cost-effective (£20 000/QALY gained threshold).

There was no evidence of statistically significant difference for caries prevalence at 2.5-years. The intervention's positive 6-month toothbrushing behaviour change did not translate into caries reduction. (ISRCTN 12139369). COVID-19 pandemic adversly affected follow-up.