Effects of Topical Fluoride on the Marginal Microleakage of Composite Resin and Resin-Modified Glass Ionomer Restorations in Primary Molars: An In-vitro Study

Topical fluoride may deteriorate dental restorations. The present study aimed to evaluate the effects of topical fluoride on the marginal microleakage of composite resin and resin-modified glass ionomer (RMGI) restorations in primary molars.
In this experimental study, 60 primary molars were randomly divided into six groups of 10 based on the type of the restoration materials and before/after the application of fluoride gel, including FC (fluoride composite), CF (composite fluoride), C (composite), FG (fluoride RMGI), GF (RMGI fluoride), and G (RMGI). Class V cavities were prepared on the buccal surface, so that the gingival margins were located in cementum. After storing, thermocycling, and immersing the specimens in basic fuchsin, they were sectioned buccolingually and evaluated in terms of dye penetration. Data analysis was performed in SPSS version 18 using Kruskal-Wallis and Mann-Whitney U test at the significance level of 0.05.
No significant difference was observed between the three composite groups in terms of microleakage (P>0.05). In the RMGI groups, GF showed a significantly higher microleakage compared to G (P=0.029). However, no significant difference was observed between the other groups in this regard (P>0.05). Moreover, comparison of composite and RMGI groups (matched in terms of fluoride application) indicated that microleakage was significantly higher in FG than FC (P=0.024), as well as in GF than CF (P=0.002). However, no significant difference was observed between groups C and G in this regard (P=0.268).
According to the results, the marginal seal of composite restorations in the primary molars were not affected by the acidic fluoride gel. On the other hand, applying the acidic fluoride gel was associated with a higher microleakage in the cavities restored with RMGI.