The Effect of Different Liners on the Microleakege of Class II Restorations after Thermocyclign and Occlusal Loading

Objective: We evaluated in vitro marginal adaptation of class II resin composite restorations with and without a liner. Materials and Methods: In total, 48 extracted sound human mandibular molars were used. The teeth were prepared following a standardized pattern for a class II cavity. The teeth were then randomly divided into four groups of 12 teeth each: group 1: resinmodified glass ionomer liner (RMGI) + composite resin (CR), group 2: flowable composite liner + CR, group 3: self-adhesive flowable composite liner + CR, and group 4: CR. The specimens were thermocycled and loaded with a mechanical loading device. The methylene blue dye penetration test was used to evaluate microleakage. Results: When specimens were evaluated for occlusal and gingival microleakage, the resin-modified and flowable composite groups showed significantly less microleakage than the control group with no liner. The self-adhesive flowable composite group showed no significant improvement. Conclusions: Flowable composite and RMGI liners were useful in decreasing microleakage, but the self-adhesive flowable composite liner showed no significant advantage.