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Monetary incentives for improving smartphone-measured oral hygiene behaviors in young children: A randomized pilot trial.



To assess feasibility, acceptability, and early efficacy of monetary incentive-based interventions on fostering oral hygiene in young children measured with a Bluetooth-enabled toothbrush and smartphone application.


A stratified, parallel-group, three-arm individually randomized controlled pilot trial.


Two Los Angeles area Early Head Start (EHS) sites.


36 parent-child dyads enrolled in an EHS home visit program for 0-3 year olds.


Eligible dyads, within strata and permuted blocks, were randomized in equal allocation to one of three groups: waitlist (delayed monetary incentive) control group, fixed monetary incentive package, or lottery monetary incentive package. The intervention lasted 8 weeks.


Primary outcomes were a) toothbrushing performance: mean number of Bluetooth-recorded half-day episodes per week when the child's teeth were brushed, and b) dental visit by the 2-month follow-up among children with no prior dental visit. The a priori milestone of 20% more frequent toothbrushing identified the intervention for a subsequent trial. Feasibility and acceptability measures were also assessed, including frequency of parents syncing the Bluetooth-enabled toothbrush to the smartphone application and plaque measurement from digital photographs.


Digital monitoring of toothbrushing was feasible. Mean number of weekly toothbrushing episodes over 8 weeks was 3.9 in the control group, 4.1 in the fixed incentive group, and 6.0 in the lottery incentive group. The lottery group had 53% more frequent toothbrushing than the control group and 47% more frequent toothbrushing than the fixed group. Exploratory analyses showed effects concentrated among children ≤24 months. Follow-up dental visit attendance was similar across groups. iPhone 7 more reliably captured evaluable images than Photomed Cannon G16.


Trial protocol and outcome measures were deemed feasible and acceptable. Results informed the study protocol for a fully powered trial of lottery incentives versus a delayed control using the smart toothbrush and remote digital incentive program administration.

Trial registration identifier NCT03862443.

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