Objective: Water fluoridation in HoChiMinh City, Vietnam, started in January 1990 at 0.7±0.1 ppm F and adjusted to 0.5±0.1 ppm F in June, 2000 but it doesn’t cover the entire metropolitan area, determining two geographical areas: Fluoridated area (F+) and non-fluoridated area (F-). To compare changes in caries experiences among 12-year-old children living between F+ and F- from 1989 to 2012 in HoChiMinh city, Vietnam.
Methods: Three multi-stratified surveys of cohorts born in 1977, 1990 and 2000. 579 twelve-year-old children were examined in 1989 (F+: 334, F-:245), 1361 in 2003 (F+: 1003, F-:358.) and 2109 in 2012 (F+: 1572, F-: 537). Data for DMFT were recorded by using WHO Criteria. Chi-square test, Mann-Whitney U-test, Kruskal-Wallis test and General Linear Models were applied.
Results: The mean DMFT significantly decreased from 3.3±2.3 in 1989 to 0.9±1.4 in 2003 and to 0.9±1.6 in 2012 in F+ (p<0.001). Smaller decrease observed in F- from 3.0„b2.2 in 1989 to 2.2„b2.4 in 2003 and 2.5„b2.3 in 2012. Proportion of caries free children (DMFT=0) in F+ greatly increased from 13.5% in 1989, to 61.8% in 2003 and 67.4% in 2012 (p<0.001). The proportion in F- also increased slightly from 16.3% in 1989, 33% in 2003 and 22.1% in 2012. There were no statistically significant differences in mean DMFT between 2003 and 2012 in both F+ and F- (p>0.05).
Conclusions: Greater decrease in the prevalence and severity of dental caries observed in F+ compared with F- support the beneficial effects of water fluoridation in caries control. A reduction in fluoride concentration from 0.7 to 0.5 ppm maintained effectiveness against caries.