Comparative Evaluation of Microleakage in Class V Composite Restorations: Er,Cr:YSGG Laser vs. Carbide Bur in Primary Teeth (In Vitro Study)

Background. Marginal microleakage is a key factor in assessing cavity preparation methods, as it affects restoration longevity and can lead to secondary caries and pulpal complications. This in vitro study compared microleakage in Class V composite restorations using Er,Cr:YSGG laser and conventional carbide bur, assessed through dye penetration. Design. In vitro study. Methods. Twenty-two sound primary molars were randomly allocated into two groups (N=11 each), with allocation based on the technique used for Class V cavity preparation. Group I - Er,Cr:YSGG laser, Group II - carbide bur. Composite resin was utilized as cavity restorative material. Samples were subjected to thermocycling, dyed, sectioned, and analyzed under a stereomicroscope. Microleakage scores and penetration depths were compared between groups using the Mann-Whitney U test, while differences between the gingival and occlusal regions within each group were analyzed using the Wilcoxon Signed Rank test. Dentin topographic features were evaluated using scanning electron microscope. Results. The significance level for statistical analysis was set at p ≤ 0.05. Microleakage at occlusal and gingival margins wasn’t statistically significant between groups (p=0.945). The Er,Cr:YSGG laser showed less microleakage at occlusal margins (p=0.046). SEM showed irregular dentin surfaces in the laser group, while bur-prepared dentin appeared more regular with minimal smear layer Conclusion. The Er,Cr:YSGG laser is a promising minimally invasive method, preserving tooth structure and patient comfort. However, surface irregularities may compromise marginal sealing and increase microleakage. Clinically, this highlights the need to optimize laser settings to improve restoration longevity and reduce complications like sensitivity and secondary caries.