+ Gel fluor 1, 23% includes effect on remineralization, prevention and neutralization of the early 6th tooth enamal lesions D1, D2 on its surface: Gel fluor 1, 23% effect on the intervened group after 18 months: 69, 8% of tooth decay at D1 become D0 level, 26, 6%: unchangeable, 3, 6% develop to D2 level; 79, 5% tooth decay at D2 level get better up to D1 level, 4, 3% unchangeable, 3, 2% develop to D3 level.