Comparative in Vitro Evaluation of Marginal Sealing in Class I Composite Restorations Using Fifth- and Seventh-Generation Adhesives.

Background: A major challenge in adhesive dentistry, often leading to restoration failure, is microleakage. This in vitro comparative study was designed to assess microleakage at the tooth-composite interface. The investigation aimed to compare the sealing efficacy of two commonly used adhesive systems.

Methods: Standardized Class I cavities were prepared on 20 extracted human molars and randomly divided into two groups (n = 10 each). Group A was treated with a fifth-generation total-etch adhesive (OptiBond™ Solo Plus, Kerr Corporation, Orange, CA, USA), and Group B received a seventh-generation self-etch adhesive (Adhese® Universal VivaPen®, Ivoclar Vivadent AG, Schaan, Liechtenstein). All restorations were completed using Herculite XRV composite resin. Microleakage was evaluated using dye penetration analysis after immersion in 2% methylene blue for 10 days, followed by longitudinal sectioning and microscopic measurement at 500× magnification.

Results: The fifth-generation adhesive group showed a mean microleakage of 0.2503 ± 0.1921 mm, while the seventh-generation group recorded 0.2484 ± 0.1764 mm. Statistical analysis using an independent t-test revealed no significant difference between the groups (p = 0.696).

Conclusions: Both adhesive systems demonstrated comparable performance in minimizing microleakage under standardized conditions. Although the total-etch group exhibited slightly lower numerical values, the difference was not statistically significant. These findings suggest that both adhesive approaches can be clinically effective when applied appropriately.