Effect of community water fluoridation on inequalities in oral health

Objectives: To determine dental caries and fluorosis prevalence and severity in fluoridated Newcastle and non-fluoridated Manchester, UK. To determine the effect of community water fluoridation on inequalities in oral health. Methods: Subjects were male and female lifetime residents aged 11-13 years. Permanent teeth were assessed for caries using ICDAS and maxillary central incisors for fluorosis using the TF Index. Results: Data from 1783 subjects were available (910 Newcastle, 873 Manchester). Index of Multiple Deprivation scores were comparable between the populations (Newcastle: mean 35.22, range 2.77-78.85; Manchester: mean 37.04, range 1.84-84.02). The fluoridated population had significantly less caries experience (p<0.001) for white spot lesions (ICDAS code 2) (Prevalence: Newcastle 75%, Manchester: 85%; mean DMFT: Newcastle 2.94, Manchester 4.48) and caries into dentine (ICDAS code 4) (Prevalence: Newcastle 33%, Manchester 46%; mean DMFT: Newcastle 0.65, Manchester 1.07). This difference was reflected across the top 4 quintiles of deprivation, but no significant difference in the least deprived quintile. The Odds Ratio for white spot caries experience in Manchester was 2.11 (95% CI 1.62, 2.68) relative to Newcastle. For caries into dentine in Manchester it was 1.84 (95% CI 1.50, 2.26) relative to Newcastle. The prevalence of fluorosis (TFI>0) in Newcastle was 55% and in Manchester 27%. The Odds Ratio for developing fluorosis in Newcastle was 3.39 (95% CI 2.78, 4.15) relative to Manchester. Conclusions: Water fluoridation is a major contributor to reducing the social class gradient between deprivation and caries experience but may increase risk of dental fluorosis when combined with fluoridated dentifrice.