Evaluation of dentin pretreatment with antibacterial zinc oxide nanoparticles and their incorporation in the adhesive system on the microtensile bond strength of resin composite to dentin versus etch and rinse bonding technique : An in vitro study / Abdelrahman Ali Abdelrahman ; Supervised Mona Ismail Riad , Rasha Raafat Hassan

Thesis (M.Sc.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Operative Dentistry

This in vitro study was carried out to asses microtensile bond strength of resin composite to dentin bonded with adper single Bond 2, a two step etch-and-rinse adhesive. Pure ZnO nanoparticles were prepared by chemical precipitation method, which were then suspended in ethanol or incorporated in the adhesive at a concentration of 50 æg/ml. Eighteen sound molars were selected for this study, six were used for ESEM analysis, while the other twelve were bonded to cylindrical ready-made acrylic blocks, and cut at superficial dentin level then randomly divided into three groups; control group A0, and dentin preatreatment by ZnO NPs A1, doped adhesive group A2, with 4 teeth in each group to produce 24 beams per group, groups A0, A2 were bonded according to manufacturer{u2019}s instructions using commercial, and doped adhesives respectively, whereas group A1 had an additional step of ethanol application after rinsing the etchant, filtek Z 250 XT was then used to produce composite build ups, each tooth was mounted in a special cutting machine to be cut in the X and Y directions to produce rectangular beams of 1 mm2 cross section for microtensile bond strength determination. ESEM analysis and elemental analysis was done to study the morphology and confirm the presence of zinc oxide within the interface. Data were then tabulated and statistically analyzed. Results: The result of the micro tensile testing revealed that the bond strength for the control group was non-significantly affected by either of the 2 interventions, results of ESEM showed that hybrid layer was present in all three groups with well-formed resin tags indicating that NPs do not alter adhesive penetration or hybrid layer formation

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