Effect of Laser Irradiation and Cavity Disinfectant Application on Bondstrength

Objective:The purpose of this invitro study was to evaluate dentin bond strength to resin composite following chlorhexidine containing cavity disinfectant application or laser irradiation by using two different adhesive systems. Methods: Thirty extracted human molars were sectioned mesio-distally, embedded in acrylic resin with buccal or lingual surfaces positioned for surface treatment and composite bonding. The teeth surfaces were ground to obtain flat dentin surfaces (n=60).They were randomly divided into six groups (n=10). Group1: 37% phosphoric acid etching, etch and rinse adhesive (Optibond Solo Plus, Kerr). Group2: Self etching adhesive (Optibond Solo Plus self Etch,Kerr). Group3: Acid etching, Cavity disinfectant application (Concepsis,Ultradent),Etch and rinse adhesive. Group4: laser irradiation (Er,Cr:YSGG laser,10Hz; 1 W; 70% Water, 50% air), acid etching, etch and rinse adhesive. Group5: laser irradiation,self etching adhesive. Group6: Cavity disinfectant application, self etching adhesive. After the respective pretreatment sequences, a teflon tube (4x2mm) was attached to the dentin surfaces and filled with nano hybrid composite (Premise /Kerr). Following storage in distilled water for 24 hours, the specimens were subjected to shear bond test. Data were analysed using Kruskall-Wallis and Mann-Whitney U tests. Results: Laser irradiatiated groups (4 and 5) were not statistically significantly different than cavity disinfectant applied self etching adhesive group(6) (p>0.05). All other groups showed significant differences (p< 0.05). Cavity disinfectant applied etch and rinse adhesive group showed the highest bond strength, whereas self etching adhesive control group (2) showed almost no bonding. Conclusion:The results indicated that the use of chlorhexidine as cavity disinfectant after acid etching showed the best bonding.