Relationship between area deprivation and the anticaries benefit of an oral health programme providing free fluoride toothpaste to young children

Objective: To determine the effectiveness of providing free toothpaste containing either 1450 or 440 ppm F on caries experience in 5-year-old children living in areas with different levels of material deprivation. Design: Five-year, examiner-blind, randomized, controlled, parallel-group, clinical trial. Children were randomly assigned to three groups. Setting: Health Districts in the north-west of England with high levels of dental caries. Clinical examinations were performed in schools during the period October 1999 to April 2000 when the children were 5-6 years old. Participants: Children from 3-month birth cohorts resident in nine, nonfluoridated health districts. Interventions: Toothpaste containing either 440 or 1450 ppm F and dental health literature posted at 3-month intervals and toothbrush provided annually from the age of 1-51/2 years. Comparison group received no intervention. Main outcome measures: Mean dmft and proportion of participants with dmft > 0, dmft greater than or equal to 4, upper primary incisor caries and extraction of one or more primary teeth. Outcomes tabulated for quartiles of participants based on the distribution of the Townsend index of material deprivation. Results: A total of 3467 children were included in the final data analysis. The Townsend index was found to be useful in identifying groups of children with increased caries risk. Overall, participants in the programme using the high-fluoride toothpaste had significantly (P < 0.002) less caries than the comparison group with similar absolute reductions in mean dmft for the most- and least-deprived groups. Relative to the comparison group the association between deprivation and dental caries was changed so that in the most-deprived quartile those using the low-fluoride toothpaste tended to have less dental caries than the comparison group whereas in the least deprived they tended to have more. This difference in the association (slope) was statistically significant (P < 0.05). Provision of both low- and high-fluoride toothpaste appeared to reduce the risk of extractions for participants in the most-deprived quartile (P < 0.05). Conclusion: The relative benefits of the programmes supplying the two toothpastes considered in this study are different depending on the deprivation status of the participants. For the most-deprived groups postal provision of either a low- or high-fluoride toothpaste provides similar levels of benefit. In the less deprived groups only provision of the high-fluoride toothpaste provided a benefit. The absolute caries reduction seen for provision of the high-fluoride toothpaste was not related to the deprivation status and hence the programme did not reduce deprivation-related health inequalities. Targeting the programme using the methods employed in this study is unlikely to improve the effectiveness of the programme.