Introduction: Dental caries in childhood is important for two reasons: 1. ‍ Childhood is the best years to form correct hygienic habits 2. There is a close relationship between the decay of deciduous teeth and permanent teeth. One of the WHO goals by the year 2010 is a caries-free index of 90% in 5 year- old children. Thus, the proportion of preschool caries- free children (DMF=0) of Hamedan was assessed in terms of socioeconomic, hygienic and nutritional factors and treatment needs.

Methods: This was a descriptive- analytic and cross- sectional study. In this study 240 children in 12 kindergartens were evaluated. Visual and tactile sensation method (mirror & e x plorer) was selected for determining the DMF. The information obtained was analyzed with Pearson chi square and Fisher's exact tests.

Results: The percentage of caries- free children was 14.7%. High percentage of caries- free teeth was observed in children who used tooth brush and dental floss indicating a significant relationship between hygienic behaviors and caries- free index. Snack feeding and duration of breast- feeding period had important influence on caries rate. Unmet restorative treatment need index (UTNI) was 98% for all these children

Conclusion: There is no significant relationship between socioeconomic status (parents education and occupation) and caries- free teeth. Caries- free index is considerably lower then the goal determined by WHO for the year 2010 (90%). A program of dental health education should be organized as a PHC activity in kindergartens.

Hakim Research Journal 2006 9(3): 39- 43.