This study was conducted to prepare the fundamental data on establishing an improvement plan for oral health promotion program, and to assess the effects of prevention to dental caries by incremental oral health care program among students of elementary school. The number of total subjects were 239 students in the care group who were controled incremental oral health care program and 195 students in the control group who were not controled incremental oral health care program. The sealant index was significantly more higher in care group than control group, especially the higher the grade. The sealant rate was significantly higher in care group than control group for all of grade. The DT index was significantly lower in care group than control group for male and female, the caries incidence rate of permanent tooth by gender was lower in male than female. The FT rate was more higher in care group than control group. The dental caries could be prevented very effectively when having continuously treated the incremental oral health care program at school dental clinic among elementary-school students. The author consider that this study will be prepare the fundamental data and contribute to oral health promotion according to a change in oral health behavior among elementary-school students. Therefore, the author recommend to expand applying the incremental oral health care program among students of elementary school.