Penetration and Adaptation of the Highly Viscous Zinc-Reinforced Glass Ionomer Cement on Contaminated Fissures: An In Vitro Study with SEM Analysis

Objective: We evaluate the penetration and adaptation of highly viscous zinc-reinforced glass ionomer cement (ZRGIC), using a scanning electron microscope (SEM), when applied under various contaminated conditions on grooves and fissures of primary second molars. Materials and Methods: A total of 40 extracted human primary second molars were randomly assigned into five groups (8 teeth each), with different surface conditions (conditioned with 40% polyacrylic acid, dry condition, water contamination, saliva contamination, or saliva contamination and air-drying) on the occlusal surface before placement of zinc-reinforced highly viscous glass ionomer cement with the finger-press technique. After sectioning the teeth, they were subjected to SEM analysis, where four in each group underwent aging by thermocycling and the other four were without aging. ANOVA tests, post hoc analysis, and unpaired t-tests were used for statistical analyses. Results: There was a significant statistical difference in the sealant penetration in the non-aging group, but in the aging group, there was no significant statistical difference in the sealant penetration. On other hand, a significant statistical difference was found in the adaptation between all the groups (p < 0.05). Highly viscous zinc-reinforced glass ionomer fissure sealants have better fissure penetration and more intimate adaptation under fissures conditioned with 40% polyacrylic acid and dry surface fissures with no contamination. However, the best penetration and retention after aging were under contaminated fissures with a shiny layer of saliva. Conclusions: Based on this study, we conclude that ZRGIC, a highly viscous fluoride-releasing cement, effectively seals fissures by interfering with food lodgment and protecting teeth from caries. We also conclude from this research that although the contaminated surfaces are not fully effective in penetrating and adapting the GIC to the tooth surface, they are still adequate for the brief period that will delay the carious process. It is advisable to restore the fissures with the minimal technique of sensitive fluoride-releasing GIC, particularly in young, uncooperative children, rather than leaving a caries-prone environment.