ABSTRACT
OBJECTIVES: This study evaluated the immediate (10-minute) and delayed (24-hour) bond strength of dual-cured resin cements that are light-activated either immediately or delayed (after five minutes) or chemically-activated only. MATERIALS AND METHODS: Three dual-cured resin cements were evaluated: RelyX ARC, Panavia F and Enforce. Cylinders of resin cement were built up over resin composite blocks following the manufacturers' instructions for each luting agent. The cements were mixed, inserted into the molds and light-activated either immediately or after five minutes (delayed light activation). When no light activation was performed, the materials were protected from light exposure until testing. Half of the samples were tested at 10 minutes; the remaining samples were stored at 100% relative humidity for 24 hours when they were then tested (n = 10). Data were submitted to three-way ANOVA and post-hoc Tukey's tests (alpha = 0.05). The failure mode was evaluated under SEM. RESULTS: RelyX ARC presented the highest values of shear bond strength, followed by Enforce. Panavia F showed the lowest values. Both immediate and delayed light activation caused the cements to present the highest means of shear bond strength. There was an improvement in bond strength after 24 hours of storage. CONCLUSIONS: RelyX ARC produced the highest bond strength, which was improved by light activation and storage for 24 hours.
Subject(s)
Resin Cements/chemistry , Self-Curing of Dental Resins/methods , Bisphenol A-Glycidyl Methacrylate/chemistry , Bisphenol A-Glycidyl Methacrylate/radiation effects , Composite Resins/chemistry , Composite Resins/radiation effects , Dental Stress Analysis/instrumentation , Drug Storage , Humans , Humidity , Materials Testing , Microscopy, Electron, Scanning , Polyethylene Glycols/chemistry , Polyethylene Glycols/radiation effects , Polymethacrylic Acids/chemistry , Polymethacrylic Acids/radiation effects , Resin Cements/radiation effects , Shear Strength , Stress, Mechanical , Surface Properties , Time FactorsABSTRACT
OBJECTIVES: The aim of this study was to evaluate the bond strength of one-step adhesive systems to dry or moist dental substrate. METHODS: Thirty human third molars were sectioned into two halves, in the mesio-distal direction, parallel to the long axis of the tooth. Each half was embedded in a polystyrene resin cylinder so that the buccal/lingual surface remained exposed. This exposed surface was abraded to obtain both flat exposed enamel and dentin. The samples were randomly allocated according to the adhesive system (Xeno III, Adper Prompt and iBond) and moisture condition (dry and moist). The substrates were air-dried for 30 s for dry condition, while the moist substrates were re-wet with 2.5 mul of distilled water after drying. After the adhesive procedures, two resin composite cylinders were build-up on dentin and enamel substrates, totaling four per sample. A shear load was applied to the samples at a crosshead speed of 0.5 mm/min until failure. Data were statistically analyzed by three-way ANOVA and the Tukey test (alpha=0.05). RESULTS: The evaluated one-step adhesives showed higher bond strength to dentin than enamel. The iBond presented better bond performance to moist substrate and Xeno III to dry substrate. The moisture condition did not interfere in the performance of Adper Prompt. The Xeno III and iBond presented higher bond strength than the other adhesives to both dry and moist substrates. CONCLUSIONS: The moisture condition of substrate interfered in the performance of one-step self-etching adhesives and the best moisture condition was material dependent.
