Abstract: PURPOSE: To investigate the coverage of pit and fissure sealants in primary and middle school students of Hangzhou city, and to explore the causes of unsealing students. METHODS: An analysis of sealing rate and unsealing causes of eligible children in Hangzhou city was carried out, using 3-year data of pit and fissure sealants program sponsored by the government. Based on the results, the validity of pit and fissure sealants as a government-sponsored public health program was evaluated. RESULTS: The sealing rate was 52.89%. The main reasons of unsealing were uneruption and incomplete eruption of teeth when the medical teams went to school for pit and fissure sealing. CONCLUSIONS: The main reason of unsealing is eruption issue, which can be controllable. Some scientific adjustments need to be made to improve the coverage, such as increasing sealing times considering the difference of teeth eruption.

Key words: Pit and fissure sealant, Sealing rate, Influential factor, Public health service