Effect of Disinfection on Bond Strength to Enamel and Dentin

The ability to rapidly disinfect the cut surface of prepared dentin and enamel without negatively affecting the restorative bond would be highly beneficial in assuring that caries causing bacteria are no longer viable or significantly reduced. Introduction: This study evaluated the effect of two disinfectant solutions-Consepsis-(C) (Ultradent Products, S. Jordan UT) a 2% sodium gluconate and an experimental thixotropic 5.25% NaOCl-(Na), as well as an H₂O control on bond strengths. Materials and Methods: Thirty dentin-(D) and thirty enamel(E) specimens were prepared by sectioning freshly extracted bovine incisors. All surfaces were uniformly prepared utilizing 600 grit sand paper under copious irrigation and randomly divided into three groups of 10 D and 10 E specimens. All specimens were treated according to the following protocol: Treatment: C was applied for 60 seconds (as per manufacturer's instructions) after etching dentin , Treatments Na and H₂0 were applied for 15 seconds, then rinsed prior to receiving a 15 second etch, rinse and slight drying. All specimens were bonded with Peak LC (Ultradent Products) as per manufacturer specifications. A 2.38mm diameter column of composite (Filtek Supreme 3M Minneapolis MN) was carefully bonded to the surface. Composite columns were sheared at 0.5mm/min. Data was collected and mean shear bond strength was calculated for each Group. ANOVA was utilized to determine differences in bond strength for each substrate Enamel and Dentin. Results: Mean Bond strengths (MPa±se); for DC, DNa and DH₂0 were 20.7±8.4, 30.3±8.8 and 30.1±8.6 respectively and EC, ENa and EH₂0 were 29.6±3.1, 40.4±5.7 and 40.2±4.8 respectively. ANOVA revealed DC and EC significantly weaker than NaOCl disinfection or control. Conclusions: Disinfection of dentin and enamel with Chlohexidine gluconate resulted in significantly weaker bond strengths than specimens disinfected with control or sodium hypochlorite.

(supported by a student research grant from NYUCD and Ultradent Products)