ABSTRACT
This study evaluated the effect of composite post placement and/or light-irradiation of dual-cure resin composite on adhesion to root canal dentin using the chemical activation mode of a 1-step self-etch dual-cure adhesive. Post spaces were prepared in extracted premolars. Root canal spaces were applied with Unifil Core EM Self-Etching Bond, which was chemically-polymerized, and then filled with Unifil Core EM with or without the placement of composite post. Half the specimens of each group were light-cured for 10 seconds and the other half were chemically-cured in darkness for 30 minutes. After 24 h storage, microtensile bond strengths (µTBS) at the coronal and apical regions were measured. When light-curing, placement of the composite post significantly reduced the µTBS to root canal dentin. On the other hand, when chemical-curing, there was no significant difference in µTBS between with and without placement of the composite post.
Subject(s)
Composite Resins/chemistry , Dental Materials/chemistry , Dental Pulp Cavity/ultrastructure , Dentin-Bonding Agents/chemistry , Dentin/ultrastructure , Post and Core Technique , Self-Curing of Dental Resins/methods , Adolescent , Dental Stress Analysis/instrumentation , Humans , Light-Curing of Dental Adhesives , Materials Testing , Microscopy, Electron, Scanning , Polymerization , Silanes/chemistry , Stress, Mechanical , Surface Properties , Tensile Strength , Time FactorsABSTRACT
The purpose of this study was to evaluate the dentin bonding durability of three HEMA-containing one-step self-etch adhesives after one-year water storage and to measure the amounts of their water sorption/solubility. OptiBond All-In-One (OP), Bond Force (BF) and Clearfil S³Bond (S³) were applied to the dentin surfaces according to manufacturers' instructions. Bond strengths to dentin were determined using µTBS test after water storage for 24 hours, six months, and one year. In addition, water sorption and solubility of the polymerized adhesives were measured. The µTBS of S³ and OP significantly decreased after one year. On the other hand, for BF there were no significant differences in µTBS between all storage periods. There were significant differences in water sorption and solubility among the adhesives (BF>S³>OP). The initial amounts of water sorption and solubility of the three adhesives did not affect their bonding durability to dentin.
Subject(s)
Dental Bonding , Dentin-Bonding Agents/chemistry , Dentin/ultrastructure , Water/chemistry , Absorption , Adsorption , Bisphenol A-Glycidyl Methacrylate/chemistry , Composite Resins/chemistry , Humans , Materials Testing , Methacrylates/chemistry , Microscopy, Electron, Scanning , Polyethylene Glycols/chemistry , Polymerization , Polymethacrylic Acids/chemistry , Resin Cements/chemistry , Solubility , Stress, Mechanical , Surface Properties , Tensile Strength , Time FactorsABSTRACT
OBJECTIVES: The purpose of this study was to evaluate the relationship between changes in the modulus of elasticity and ultimate tensile strength of one-step self-etch adhesives, and their degree of water sorption. METHODS: Five one-step self-etch adhesives, Xeno IV (Dentsply Caulk), G Bond (GC Corp.), Clearfil S3 Bond (Kuraray Medical Inc.), Bond Force (Tokuyama Dental Corp.), and One-Up Bond F Plus (Tokuyama Dental Corp.) were used. Ten dumbelled-shaped polymers of each adhesive were used to obtain the modulus of elasticity by the three-point flexural bending test and the ultimate tensile strength by microtensile testing. The modulus of elasticity and the ultimate tensile strength were measured in both dry and wet conditions before/after immersion in water for 24h. Water sorption was measured, using a modification of the ISO-4049 standard. Each result of the modulus of elasticity and ultimate tensile strength was statistically analyzed using a two-way ANOVA and the result of water sorption was statistically analyzed using a one-way ANOVA. Regression analyses were used to determine the correlations between the modulus of elasticity and the ultimate tensile strength in dry or wet states, and also the percent decrease in these properties before/after immersion of water vs. water sorption. RESULTS: In the dry state, the moduli of elasticity of the five adhesive polymers varied from 948 to 1530 MPa, while the ultimate tensile strengths varied from 24.4 to 61.5 MPa. The wet specimens gave much lower moduli of elasticity (from 584 to 1073 MPa) and ultimate tensile strengths (from 16.5 to 35.0 MPa). Water sorption varied from 32.1 to 105.8 g mm(-3). SIGNIFICANCE: The moduli of elasticity and ultimate tensile strengths of the adhesives fell significantly after water-storage. Water sorption depended on the constituents of the adhesive systems. The percent decreases in the ultimate tensile strengths of the adhesives were related to water sorption, while the percent reductions in the moduli of elasticity of the adhesives were not related to water sorption.
