Objectives : Both adhesive and collagen degradation have been regarded as major causes of resin–dentin bonds failures. Complete infiltration of hydrophobic resins facilitated by ethanol, and the presence of MMPs inhibitor within the hybrid layer would build the ideal interface, resistant to hydrolysis and enzymatic activities. This study examines the benefits of the adjunctive use of chlorhexidine and ethanol on the durability of resin–dentin bonds.
Methods : Forty-eight flat dentin surfaces were etched (32% PA), rinsed (30 s) and blot-dried with absorbent paper. The surfaces were re-wetted with either water (water); 1% chlorhexidine diacetate in water (CHX/water); 100% ethanol (ethanol); and 1% chlorhexidine diacetate in ethanol (CHX/ethanol) solutions for 30 s. They were then bonded with All Bond 3 (AB3, Bisco) or Excite (EX, Ivoclar-Vivadent) using a smooth, continuous rubbing application (15 s), followed by 15 s gentle air stream. The adhesives were light-cured (20 s) and resin build-ups constructed for the microtensile method. Bonded beams were obtained and tested after 24 h, 6 months, and 15 months water storage at 37 °C. Storage water was changed every month. Effects of treatment and testing periods were analyzed (ANOVA, Holm-Sidak, p < 0.05) for each adhesive.
Results : There was no interaction between factors for both adhesives. AB3 was significantly affected by storage, but not by treatments. Excite was significantly affected by treatments, but not by storage.
|Dentin surface treatments||Microtensile bond strengths (MPa). Least-square mean ± SEM. N = 6/group|
|All bond 3||Excite|
|24 h||6 months||15 months||24 h||6 months||15 months|
|Water||51.07 ± 3.6 A,a||57.13 ± 3.6 A,a||47.29 ± 4.4 A,a||49.51 ± 5.4 A,B,a||42.10 ± 5.4 A,B,a||45.51 ± 6.6 A,a|
|Water/CHX||46.96 ± 3.6 A,a||50.69 ± 3.6 A,a||46.07 ± 4.4 A,a||40.05 ± 5.4 B,a||36.78 ± 5.4 B,a||42.48 ± 5.4 A,a|
|Ethanol||59.41 ± 3.6 A,a||56.41 ± 3.6 A,a,b||44.41 ± 4.4 A,b||49.67 ± 5.4 A,B,a||44.56 ± 5.4 A,B,a||40.87 ± 6.6 A,a|
|Ethanol/CHX||54.67 ± 3.6 A,a||52.17 ± 3.6 A,a,b||39.58 ± 4.4 A,b||53.37 ± 5.4 A,a||57.47 ± 5.4 A,a||49.55 ± 6.6 A,a|