Influence of metalloproteinases on dentin hybridization of one-bottle or self-etch dental bonding systems.

Aim: To assess the influence of dentin substrate and chlorhexidine on the marginal seal of composite resin restorations.
Materials and Methods: The sample comprised 20 third molars. Four cavities were drilled in the dentin sur face, followed by sealing and restoration of sound dentin (n = 10) or carious dentin (n = 10). In the control group, cavities were immediately restored as follows: G1: one-bottle bonding agent (OB) + composite resin (CR); G2: chlorhexidine 2.0% (CLX) + OB + CR; G3: self-etch bonding agent (SE) + CR; G4: CLX + SE + CR. In the experimental group (carious dentin), carious lesions were induced with S. mutans and cavities were restored as in the control group. Five specimens from each group (sound and carious) were stored in brain-heart infusion (BHI) medium for 6 months. All specimens were submerged in methylene blue 0.5% to test for microleakage. The Kruskal-Wallis and Student-Newman-Keuls tests were used to assess results.
Results: On immediate assessment, there were no significant between-group differences in the sound dentin group, whereas in carious dentin, there was less leakage when OB and CLX were used. At 6 months, there was less leakage in the sound dentin group when OB and CLX were used; there were no between-group differences in carious dentin. Comparison of immediate and 6-month assessments showed a significant increase in leakage at 6 months when sound dentin was treated with SE and CLX and when carious dentin was treated with OB and CLX.
Conclusion: To ensure better dentin hybridization and preservation of the organic constituents of the dentin matrix, the properties of chlorhexidine digluconate and the components of the resin matrix must be taken into account.
Clinical Significance: Metalloproteinases influence degradation of the hybrid layer in composite resin restorations, regardless of whether the bonding system used is one-bottle or self-etching.