Fissure sealant retention and caries development after resealing on first permanent molars of children with low, moderate and high caries risk.

AIM: This was to evaluate the retention of fissure sealants (FS) and their effectiveness after resealing on caries reduction applied to first permanent molars, in a sample of children stratified according to their caries risk status in a private practice setting.
METHODS: The sample was 1,274 FS applied on first permanent molars (FPM) of 380 children (6 to 8 years old). Follow-up and monitoring for resealing was 3 years after FS placement, having at least one recall visit per year. Caries risk was based on baseline dmft index: low (dmft=0), moderate (dmft=1-4), high (dmft >4), with almost half of the teeth belonging to the high-risk group. All sealed teeth were evaluated and recorded for FS failure and resealing in case of partial/total loss, as well as caries development. Survival analysis using the Cox Proportional Hazards regression model was used for data evaluation.
RESULTS: Of the 1,274 sealed surfaces, 927 (72.8%) needed no intervention 185 (14.5%) needed only resealing and 162 (12.7%) developed caries during the study. Of 162 carious surfaces, 107/ 675 (15.9%) were from the high caries risk children, compared with 17/144 (11.8%) and 38/455 (8.3%) from the moderate and low caries risk group respectively. The highest number of failures, 4.9% and resealing were found at first recall, declining to 1.4% at the end of the study. Development of caries followed a steady rate of 6-8% per year. Cox proportional hazards model indicated, regardless if resealing or caries development was considered a failure or resealing was a success and caries development a failure, only the high dmft index appeared in both cases to significantly increase the chance (158% and 173% respectively) of FS failure and caries development compared with moderate and low dmft index. Other variables when inserted into the hazard model, such as age, sex and number of visits, either did not show a significant effect or only marginally affected FS retention, without modifying the association between caries risk and sealant failure.
CONCLUSIONS: Children of a high baseline caries risk status showed lower FS retention rates and higher occlusal caries prevalence following FS loss compared with those of moderate and low risk status. Resealing does not seem to dramatically change the final outcome of the higher risk group to develop more caries, necessitating other more effective measures to increase the retention of FS on these highly vulnerable areas.