Comparison of Different Dentin Deproteinizing Agents on Bond Strength and Microleakage of Universal Adhesive to Dentin

Aim: To evaluate the effects of papain (Brix 3000), bromelain, sodium hypochlorite (NaOCl), and chlorine dioxide (ClO2) application to the deep dentin surface on shear bond strength (SBS), microleakage, and dentin surface properties. Materials and Methods: Deep dentin surface (n = 100) for evaluating SBS, class V preparation at the buccal surface for testing microleakage (n = 100), and deep dentin slices (n = 20) for evaluating surface properties were conducted on the 220 molar teeth. Four different deproteinizing agents (Brix 3000, 40% bromelain, 5.25% NaOCl (Chloraxid), and 0.12% ClO2) were applied to the dentin, and then the universal adhesive was used in self-etch (SE) and etch&rinse (E&R). Deproteinizing agents were not applied to the control group. All of the samples were subjected to 5000 cycles of thermal aging at 5ºC–55ºC. SBS (MPa) was tested by a universal testing machine. The microleakage of resin composite bonded with different adhesive modes was evaluated under a stereomicroscope. The changes in the surface morphology were examined with scanning electron microscopy (SEM) and attenuated total reflection – fourier transform infrared spectroscopy (ATR-FTIR). Results: ClO2 exhibited the highest bond strength among deproteinizing agents. Compared to the SE mode, E&R mode significantly showed higher bond strength (p < .05). In gingival margin, bromelain SE exhibited the highest marginal leakage, while Brix 3000 SE had the lowest mean microleakage score. Conclusion: Deproteinizing with ClO2 was effective in improving the SBS of universal adhesive in the E&R mode to deep dentin. Deproteinization with bromelain before universal adhesive in SE mode showed more microleakage on both the occlusal and gingival surfaces.