An ex vivo evaluation of effect of dentin pretreatment with various agents for varying time intervals on the shear bond strength of resin

Background This article highlights the contribution of collagen structure/stability to the bond strength. We hypothesize that induction of cross-linking in dentin collagen fibrils improves dentin collagen stability and thus bond strength with composite also improves. Aims The aim of the study was to evaluate the effect of collagen cross-linking agents on the shear bond strength of composite resins. Subjects and Methods One hundred human permanent teeth were randomly divided into three groups: Group I (n = 20) - no dentin pretreatment done, Group II - dentin pretreatment with 10% sodium ascorbate for 5 min (IIa) and 10 min (IIb), and Group III - dentin pretreatment with 6.5% proanthocyanidin (PA) for 5 min (IIIa) and 10 min (IIIb). A composite resin was bonded on prepared surfaces and cured. Thermocycling was done, and shear bond strength of the prepared samples was tested using a universal testing machine. Results Values of Group I (control) were lowest whereas that of Group II (sodium ascorbate) were highest. The following order of shear bond strength was observed: IIb > IIa > IIIb ~ IIIa > I. Results for sodium ascorbate were found to be time dependent, whereas for PA, differences were nonsignificant. Conclusions Treatment of dentinal surfaces with collagen cross-linking agent increases the shear bond strengths.