The prevalence and severity of fluorosis and other developmental defects of enamel in children who received free fluoride toothpaste containing either 440 or 1450 ppm F from the age of 12 months

Abstract

Objective: To assess the impact of a programme regularly supplying free fluoride toothpaste to children on the prevalence and severity of fluorosis and other developmental defects of enamel.

Design: Randomised, controlled, parallel three-group clinical trial. Two groups received toothpaste containing either 440 or 1450 ppm F; the third group received no intervention. Children were supplied with toothpaste and advice on its use from the age of 12 months until they were 5-6 years old. The participants were a sub sample of those involved in a study that considered the caries benefits of providing free fluoride toothpaste. They were eligible if they completed the main study, lived in four of the nine districts involved and attended schools with 6 or more eligible participants.

Setting: Children from the north west of England consuming drinking water containing less than 0.1 ppm F were examined in primary schools.

Participants: 3731 children completed the main study. Of the 1833 children in the four selected districts, 927 were from schools with six or more participants.

Method: Digital images encompassing the upper and lower anterior sextants were taken of each child when they were 8-9 years old.

Main outcome measures: Developmental defects of enamel and dental fluorosis (TF index) were recorded on upper central incisors from wet and dry images.

Results: A total of 703 children were included in the data analysis. In the 1450 ppm F (n=218), 440 ppm F (n = 226) and control (n = 259) groups the prevalence of dental fluorosis (TF > 0) was 17%, 15% and 12% for the wet (p > 0.05) and 26%, 24% and 25% for the dry (p > 0.05) photographs respectively. The prevalence of TF scores 2 or 3 (highest score) was 5%, 4% and 2% and for the wet (p > 0.05) and 7%, 4% and 5% for the dry (p > 0.05) photographs respectively. All subjects identified with TF score 3 were found in the group using the 1450 ppm F toothpaste (3 wet and 4 dry) and there were statistically significant differences between the three groups for both wet (p = 0.03) and dry photographs (p < 0.01). However, the pairwise comparisons between the groups failed to attain statistical significance. The highest prevalence and severity of demarcated opacities was seen in the control group and for the wet photographs the difference between the three groups attained statistical significance (p = 0.04). For both the wet and dry photographs the prevalence of any enamel defects (including fluorosis) and large demarcated or TF score 3 was similar for the three groups (p > 0.05).

Conclusion: Previously it has been reported that only the provision of 1450 ppm F toothpaste provides anticaries benefits in a programme of this type. This benefit is accompanied by a slight increase in prevalence of TF score 3 but not the overall prevalence of developmental defects of enamel. Careful targeting and implementation of a programme of this type is required to maximise benefits and minimise risks of fluoride exposure.