The Effect of MI Varnish™ on Caries Increment and Dietary Habits among 6- and 12-Year-Old Children in Riga, Latvia: A 3-Year Randomized Controlled Trial

Aims: This randomized controlled trial investigated the effect of MI Varnish™ (5% NaF/CPP-ACP) on caries increment in 6- and 12-year-old children in Riga, Latvia within 36 months. Methods: Forty-eight 6-year-old children (Group 1) and forty-seven 12-year-old children (Group 3) received quarterly varnish application, while forty-eight 6-year-old children (Group 2) and thirty-seven 12-year-old children (Group 4) did not have varnish applied. All children/parents received the same preventive advice. All children were visually examined using ICDAS-II criteria. Questionnaires on dietary habits were completed by the children/parents at baseline and after 36 months. DMFS and dfs were calculated from ICDAS data. The statistical analysis was performed (α = 0.05) using a Chi-squared test, paired t-test (Welch test) and the Pearson correlation coefficient. The trial registration number is ISRCTN10584414. Results: In Group 1 versus Group 2, the DMFS(SD) (Baseline/36 months) values were 5.02(5.85)/13.21(6.67) (p < 0.001) versus 2.65(4.54)/10.81(6.14) (p < 0.001), respectively; the dfs(SD) (Baseline/36 months) values were 36.75(12.96)/24.04(12.9) (p < 0.001) versus 33.67(12.74)/23.88(11.91) (p < 0.001), respectively. In Group 3 versus Group 4, the DMFS(SD) (Baseline/36 months) values were 48.62(23.18)/70.96(23.28) (p < 0.001) versus 34.73(17.99)/54.95(16.09) (p < 0.001), respectively; the dfs(SD) (Baseline/36 months) values were 1.7(4.4)/0 (p < 0.05) versus 2(6.39)/0 (p = 0.06), respectively. The prevalence of caries (dfs + DMFS) decreased by 4.52 (p < 0.001) and 1.63 (p < 0.001) in Groups 1 and 2, respectively, but increased by 20.64 (p < 0.001) and 18.22 (p < 0.001) in Groups 3 and 4, respectively. An analysis of the questionnaires indicated the habitual, frequent consumption of a sugary diet by all the children. A significant correlation (r = 0.321; p < 0.05) was observed between caries increment and the frequency of daily intake of sugary snacks, soft drinks and tea with sugar at baseline only in Group 1. Conclusions: A quarterly application of MI varnish (CPP-ACP/fluoride) reduced caries increment in 6- and 12-year-old children in Riga, Latvia.