The importance of dentin collagen fi brils on the marginal sealing of adhesive restorations: An in vitro study

Aim: This study is aimed to evaluate the importance of collagen fi brils in the adhesion of diff erent self-etching adhesive materials to dentin. Methods: Sixty Class V restorations were prepared on the buccal and lingual surfaces of 30 recently extracted human premolars, with the cervical margins in dentin and the occlusal margins in enamel. These restorations were distributed to three groups of 20 cavities each based on the employed adhesive system used: Group A: G-Bond (GC, Corporation Tokyo, Japan); Group B: Xeno V (Dentsply Caulk Milford, DE, USA); Group C: Adper Easy One (3M/ESPE). Each group was subdivided according to dentin treatment: Subgroup 1 manufacturer’s adhesive protocol and Subgroup 2 Removal of the collagens fi bers (total etch + sodium hypochlorite 5% for 2 min) + adhesive protocol. After the restorations, the teeth were subjected to thermal cycling, washing and scoring according to dye penetration. Dye penetration was evaluated using steriomicroscope. Results: When the dentin microleakage scores were compared in subgroups A1VsA2, B1VsB2 and C1VsC2, then Mann–Whitney test revealed signifi cant diff erences between Subgroup A1 and Subgroup A2 (P < 5%). There was no signifi cant diff erence in Groups B and C. Conclusion: The results revealed that the collagen fi brils are not required for adhesion, and their removal improves the marginal seal of G-Bond, an acetone based dentin bonding system.