In Vitro Microleakage Comparison of Three Pit-and-Fissure Sealant Protocols: Self-Etch Sealant with and Without Separate Adhesive Versus Conventional Resin-Based Sealants

<b>Background:</b> Pit-and-fissure sealants are a fundamental preventive strategy in occlusal caries management, particularly in children and adolescents. The effectiveness of sealants largely depends on their marginal sealing ability, which prevents microleakage and subsequent bacterial penetration. <b>Objective:</b> This in vitro study aimed to compare the microleakage performance of three sealant protocols: Fissurit FX (VOCO GmbH, Cuxhaven, Germany), Perma Seal Perma Seal (Ultradent Products Inc., South Jordan, UT, USA) with an adhesive system, and Perma Seal without adhesive. <b>Methods:</b> A total of 18 extracted human molars were randomly divided into three groups (n = 6/group). Following standard enamel cleaning and acid etching, sealants were applied according to the manufacturer's instructions. Samples were thermocycled, immersed in 5% methylene blue, sectioned bucco-lingually, and evaluated for dye penetration under magnification. Microleakage was scored on a 0-3 scale. Intra-examiner reliability was assessed with Cohen's kappa. Statistical analysis included Kruskal-Wallis, Chi-Square, and Wilcoxon signed-rank tests. <b>Results:</b> The Kruskal-Wallis test revealed significant differences between groups (<i>p</i> = 0.006). Perma Seal with adhesive demonstrated the lowest microleakage scores, followed by Fissurit FX, while Perma Seal without adhesive showed the highest leakage. Cohen's kappa of 0.952 indicated excellent scoring reliability. Chi-Square analysis confirmed the association between material and leakage pattern (<i>p</i> = 0.003). <b>Conclusions:</b> The use of an adhesive system prior to self-etch sealant application significantly enhances marginal sealing and reduces microleakage. These findings support the incorporation of adhesive pre-treatment protocols into clinical practice to optimize sealant efficacy.