The Effects Of Different Surface Treatments On Micro-tensile Dentin Bond Strengths Of Self-etch/Adhesive Resin Cements And Resin-modified Glass Ionomer Cements

Objectives:The aim of this study was to investigate the effects of different surface treatments on the micro-tensile dentin bond strengths (μTBS) of self-etch/adhesive resin cements and resin-modified glass ionomer cements (RMGIC).Methods:Thirty-six non-carious human third molars were used for this study. The molars roots were imbedded with a self curing resin up to enamelo-cemental junction(CEJ). A3-mm high resin crown (Dulrafill VS, Heraeus Kulzer, Germany) was built up on molar occlusal surface using a conventional enamel adhesive Durafill Bond (Heraeus Kulzer, Germany).The crowns were cut in two with a low-speed saw (Isomet1000, USA) along the middle one third of crowns, perpendicularly to tooth long axis in order to expose the dentin surfaces of both sectioned sides. Twenty-seven molars were randomly assigned into five groups according to five cements (two self-etching resin cements:Panavia F (Kuraray Co, Japan), ResiCem (Shofu, Japan), and two self-adhesive resin cements:Rely X Unicem (3M ESPE, Germany), seT PP (SDI, Australian), and one resin-modified glass ionomer cement:Fuji CEM(GC. Japan)). The sectioned dentin surfaces were treated with or without dentin bonding agents. The dentin bonding agents were strictly applied according to manufacturer's instruction. Subsequently, two same pretreated dentin surfaces were glued together in situ with one of the five cements under finger pressure for5min. After the specimens at dentin-cement interfaces had been covered by Vaseline, and stored in water for24h, halves of them were perpendicularly sectioned through the dentin-cement interfaces, preparing into beams about1x1x8mm for μTBS tests with micro-tensile tester (Bisco Co. USA). The others were perpendicularly sectioned through the dentin-cement interfaces to expose dentin-cement interfaces. They were prepared into one1-mm thick piece per specimen. Specimens had been immersed in0.1mol/1HC1for30s, and rinsed before they were dehydrated in ascending concentrations of ethanol and gold sputter-coated. Subsequently, the micro-morphologies of the dentin-cement interfaces were analyzed by SEM (ULTRA55; ZEISS, Germany). The data were analyzed with factorial design ANOVA, and Post Hoc LSD for multiple comparisons.Results:ResiCem (16.7±5.3Mpa) and Panavia F (16.9±5.5Mpa) showed the highest dentin bond strength in the study (p0.01), Rely X Unicem (13.5±3.5MPa) possessed a higher dentin bond strength than seT PP (4.0±2.4MPa) and Fuji CEM (3.7±1.1MPa)(p<0.01). Self-adhesive cements (Rely X Unicem, seT PP) and RMGIC (Fuji CEM) with pre-treatment of respective dentin bonding agents exhibited a significantly higher dentin bond strengths than those without pre-treatment of dentin bonding agents (p<0.05), but self-etch resin cement (ResiCem) with pre-treatment of BeautiBond could not improve dentin bond strengths (p<0.05). SEM revealed a intimate contact at interfaces of dentin and cements (Panavia F, ResiCem, Rely X Unicem), and porosities at the dentin-cements (seT PP, Fuji CEM) interfaces. There were few micro-porosities at the pretreated dentin-cement interfaces except ResiCem.Conclusion:1. ResiCem possessed similar dentin bond strength to Panavia F. Both self-etch resin cements possessed significantly higher dentin bond strengths than self-adhesive cement (Rely X Unicem, seT PP) and RMGIC (Fuji CEM).2. The pretreatment of dentin bonding agents could significantly improve the self-adhesive cements (Rely X Unicem, seT PP) and RMGIC (Fuji CEM), but could not improve self-etch resin cement (ResiCem)...