Supplementary Material for: A cluster randomised controlled trial of a targeted distributed toothpaste and toothbrushing programme

Introduction:
The aim is to assess the effectiveness of a distributed, targeted toothbrush and toothpaste programme on referrals for tooth extraction under Dental General Anaesthetic (DGA), in children of high-risk families compared to usual care.
Methods:
A recruiter and assessor-blinded, clustered parallel randomised control trial (RCT). Families with one or more children aged between 3 and 10 years having undergone a DGA operation for extraction of carious teeth, were approached within hospitals in the North West of England. Families were randomised at the cluster level in a 1:1 ratio. All eligible children within the family were consented into the study. The primary outcome was participant referral for a DGA 6 to 24 months post randomisation.
Results:
A total of 961 families (1671 children) were randomised, 482 families (832 children) to the intervention, and 479 families (839 children) to the control group. Families (1662 children, 955 families) were included in the final analysis (825 intervention, 837 control). Marginal regression models (generalized estimating equation approach) taking into account cluster membership were used to model the effectiveness of the intervention at 24 and 48 month follow-up, including the variables, age, sex and IMD quintile. Seventy-six children (9.2%) in the intervention group had a DGA referral within 2 years compared to 57 children (6.8%) in the control group. The study found no effect of a clinically meaningful difference between the intervention group and usual care (Risk Ratio 1.36, 95% CI 0.98 to 1.89) in reducing referral for DGA for a targeted postal toothpaste/toothbrush program in a contemporary, population with previous family experience of DGA residing in an area of high deprivation.
Conclusion:
The target of the intervention (families of children with a DGA) was the correct focus given the referrals observed over 2 and 4 years. The study can aid policymakers, local authorities and commissioners to understand repeat DGA within families and further need for intervention.