The purposes of the present study were 1) to evaluate the effectiveness of
a school-based sealant program in different settings, and 2) to examine the most common
failures of the school-based sealant program. The design was a follow-up study of the
school-based sealant program. Twelve contracting units of primary care and 1,703 children
with 4,121 teeth were included. Sealant retention and caries on sealed surfaces were
examined for 6 months after sealant application. Full sealant retention was 41.2 % and caries on
sealed surfaces presented 4.1 %. The hospital-based service provided 1.56 times more
full sealant retention than the mobile service. However, there was no significant effect of
such setting services towards caries on sealed surfaces. The most common failures were
partial retention with ledge and caries present, loss of sealant on poor oral hygiene surfaces,
loss of sealant at the cervical part of the buccal groove of lower molars, and loss of sealant
at the distal groove of the occlusal surface of lower molars. In conclusion, the quality
of school-based sealant services should be improved, especially mobile dental services,

and the most common failure causes should be reviewed.