Effect of the widespread use of fluorides on the occurrence of hidden caries in children.

Background: It has been suggested that the widespread use of fluorides could interfere in the prevalence of clinically undetected occlusal dentine caries.
Aim: The objective of this study was to determine the role of public water fluoridation and fluoride dentifrice on the prevalence of hidden caries in 8-10-year-old children.
Design: Clinical and radiographic data on schoolchildren collected in an epidemiologic study in Porto Alegre, Brazil, at two moments, 1975 (n = 228) and 1996 (n = 213), were analysed. Only the first permanent molars were studied. Only children of the 1996 examinations had benefited from fluoridated water soon after birth and had regular access to fluoride dentifrices. The criterion applied for hidden caries, when data from 1975 to 1996 were compared, was clinical sound surfaces that presented a radiolucent zone in the dentine.
Results: The prevalence of clinically sound surfaces and percentage of hidden caries was 0.51 and 26.4% in 1975 and 2.67 and 12.9% in 1996, respectively. The prevalence of hidden caries differed statistically between the two periods (P < 0.05).
Conclusions: The results do indicate that the widespread use of fluoride via public water supply and dentifrices decreases the prevalence of hidden caries.
(© 2012 The Authors. International Journal of Paediatric Dentistry 2012 BSPD, IAPD and Blackwell Publishing Ltd.)