Comparing the caries-preventive effect of two fissure sealing modalities in public health care: a single application of glass ionomer and a routine resin-based sealant programme. A randomized split-mouth clinical trial.

Aim: The aim of this study was to compare the caries-preventive effect of two types of sealant modalities and to evaluate whether the caries-preventive effect is related to sealant retention. A hypothesis was tested in which a glass ionomer sealant, once applied to the occlusal surface, was able to protect the fissure from caries even if the sealant appeared lost at visual inspection.
Design: A 3-year randomized split-mouth trial evaluating two sealant modalities was performed at a public health centre in Finland. A chemically curing glass ionomer cement (GIC) and light-curing resin-based (RB) sealant material were applied randomly to the permanent second molars. Sealant application as a routine treatment procedure was carried out to 599 children in the age group of 12-16 years. Caries rate of the sealed teeth and sealant retention with both materials were analysed by a modified McNemar's test. The effectiveness, rate difference, and relative risk with both sealant materials were measured.
Results: The difference in caries rate between the two modalities was highly significant. When compared to the GIC sealant method, the effectiveness of RB sealant method was 74.1% and the rate difference 3.2% (95% CI 1.44%, 4.98%). The relative risk for RB-sealed surfaces vs. GIC-sealed surfaces of having detectable dentin caries was 0.26 (95% CI 0.12, 0.57). The retention rate of sealants was higher with RB than GIC (P < 0.001). The effectiveness of the retention rate for RB sealants was 94.8% and the rate difference 87.2% (95% CI 83.86%, 90.50%). The relative risk during the 3-year study period of having a defective or lost RB sealant was 0.052 (95% CI 0.036, 0.075) when compared to having a defective or lost GIC sealant.
Conclusion: It is concluded that in preventing dentin caries a RB sealant programme including resealing when necessary was more effective than a single application of GIC. The original hypothesis was thus falsified.