In vitro evaluation of shear bond strength of polymethyl methacrylate/montmorillonite modified Biodentine with dental resin composite

Abstract

Purpose The aim of this study was to evaluate the bond strength between Biodentine, modified with polymethyl methacrylate/Montmorillonite nanoclay, and resin composite at different stages of Biodentine's setting time. Materials and Methods Nanoclay was prepared and organo-modified with polymethyl methacrylate. The characterization of polymethyl methacrylate/Montmorillonite nanoclay, Biodentine, and modified Biodentine was assessed by X-ray diffraction analysis, Fourier-transform infrared spectroscopy, and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. A total of sixty acrylic molds were constructed; thirty specimens were filled with Biodentine, and the other thirty with nanoclay-modified Biodentine. Each group was subdivided according to different stages of Biodentine's setting time: 12 minutes, 2 hours, and 2 weeks. Universal adhesive, followed by flowable resin composite, was applied. The microshear bond strength was tested using a universal testing machine. Data were analyzed using one-way ANOVA followed by Tukey’s post hoc test, in addition to two-way ANOVA. The significance level was set at p ≤ 0.05. Results The characterization results revealed the successful preparation of polymethyl methacrylate/Montmorillonite nanoclay and modified Biodentine. The micro-shear bond strength results showed that modified Biodentine had significantly higher micro-shear bond strength than unmodified Biodentine at 12 minutes. However, no statistically significant difference was found between the unmodified and modified Biodentine groups at 2 hours and 2 weeks. Conclusion The incorporation of 10% modified nanoclay by weight into Biodentine could enhance the bond strength with resin composite when placed after 12 minutes of Biodentine's setting time