This study obtained DMFT index(9271 people) in population with more than 6 years old based on data of 2009 Korea National Health and Nutrition Examination Survey, and calculated SiC index(2,517 people) by classifying group with high risk, which is 1/3 in high rank out of it. The aim was to confirm existence of the group with high risk of dental caries, and was to emphasize necessity of preventive strategy for the group with high risk. Statistical analysis was carried out t-test by using STATA 11.0 program. 1. DMFT index accounted for 45.0%(4,174 people) for men and 55.0%(5,097 people) for women. SiC index stood at 2,517 people. Men accounted for 36.3%(914 people). Thus, women were larger with 64.7%(1,603 people). 2. Seeing the mean in DMFT index and SiC index, the more rise in age led to the bigger difference in the mean between two groups. Especially, the difference was shown more than 4 points on the average for 13 and 14 years old and more than double on the average from over 15 years. 3. As a result of comparing gender, DMFT index was higher in women than men from over 14 years old. SiC index wasn`t significant. However, women were indicated to be 1 piece more than men at the age of 9 and 14. 4. As a result of comparing by region, both DMFT index and SiC index were indicated to be higher in the rural area for their over 60s. Seeing the above results, the group with high risk is showing the higher rate of experiencing dental caries than DMFT-index in the whole. Thus, the comprehensively & intensively preventive management seems to be likely needed on group with high risk.