An epidemiological survey has been achieved on elementary and secondary schoolchildren of five different areas in the territory of Ussl no 16 in Lecco. The study, performed on a randomly sample of 458 children aged 6, 10, 12 years, used the epidemiological indexes DMFT/dmft and CPITN to monitor dental and periodontal status. The treatment needs of the subjects was monitored too and the amount of Streptococco mutans in 6 years old schoolchildren, using spittle drawning, was investigated. The results seem to show that the DMFT/dmft values are on a moderate level as regards the European goals, while the amount of dental and periodontal treatment performed is very low. The gingivitis prevalence is high, as well as scaling is required in many children. The analysis of the spittle samples drawned in 6 years old schoolchildren points out high levels of Streptococcus mutans as regard those collected in other similar studies achieved by our Department. According to the results analysis, two sorts of preventive intervention were planned to have the maximum preventive efficacy according to the disease level located in the different areas.