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Purpose: The purpose of this study was to evaluate the in vitro dentin bond strengths of two dentin bonding systems in Class I cavities following fatigue load cycling (FLC) with thermal cycling (TC). Materials and Methods: Class I cavities were prepared in 12 human molars and restored with either Clearfil SE Bond (SE) and Clearfil AP-X resin composite (AP-X) or Single Bond (SB)/AP-X according to the manufacturers' instructions. After water storage for 1 week, untreated controls and test samples were subjected to 50,000 FLC with TC from 5°C to 55°C for 625 cycles and stored in water for 1 week. Microtensile bond strength (MTBS) tests were measured on the floor of the cavities at a crosshead speed of 1 mm/min. Data were statistically analyzed using one- and two-way ANOVA and Fisher's PLSD test at a 5% level of significance. Results: The MPa results were: SE 30.5 ± 12.8 (control) and 23.2 ±10.8 (50,000 FLC); SB 5.1 ± 9.2 (control) and 4.7 ± 5.7 (50,000 FLC). Bond strengths were not statistically significantly affected by FLC (p > 0.05); however, they were influenced by the bonding system (p < 0.05). The MTBS of SE was significantly higher than that of SB (p < 0.05) under FLC and TC test conditions. Over half of the SB specimens debonded during sample preparation, showing blister-like structures, suggesting that an over-wet phenomenon occurred on the cavity floor. Conclusion: SE produced excellent dentin bonds that were much stronger than those produced by SB, which was shown to be a technique-sensitive bonding system. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to determine if treatment of experimentally demineralized dentin with a calcium phosphate precipitating (CPP) solution could restore the bond strength or self-etching adhesives to that of normal mineralized control values. Materials and Methods: The occlusal surfaces of human teeth were exposed for bonding. The teeth were assigned to a mineralized control group or one of three demineralized (40% phosphoric acid for 60 s) experimental groups. One of the experimental groups remained untreated, while the other two were treated with the CPP solutions for either 1 or 10 min. All experimental groups were then chemically dehydrated with ascending acetone concentrations to prevent shrinkage prior to bonding with Clearfil Liner Bond 2 (LB2) or MacBond II (MBII). Composite buildups were made and vertically, serially sectioned into multiple slabs about 0.7 mm thick. Each slab was then trimmed for microtensile bond testing and SEM examination. Results: Both self-etching adhesives produced high bond strengths to control mineralized dentin (ca 42 and 37 MPa for LB2 and MBII, respectively). Acid etching with 40% phosphoric acid for 60 s followed by chemical dehydration significantly lowered (p < 0.05) bond strength to 26 and 27 MPa for LB2 and MBII, respectively, and created hybrid layers between 7 and 8 urn thick. When the demineralized dentin was treated with the CPP solution for 1 min, the bond strengths increased (p < 0.05) to 39 for LB2 and 42 MPa for MBII. and the hybrid layers were 11 jjm thick. Increasing the CPP treatment time to 10 min lowered [p < 0.05) bond strengths but increased the hybrid layer thickness to 16 to 20 um. Conclusion: The use of calcium phosphate precipitating solutions may permit higher bond strengths of self-etching primers to demineralized (eg, caries-affected) dentin. [ABSTRACT FROM AUTHOR]

Resin coating technique is a unique method that improves the dentin bond strength of resin cements in indirect restorations. However, the weak link of a specimen bonded using the resin coating technique was reported to be the bonded interface between the resin coating material and resin cement. The purpose of this study, therefore, was to enhance the bonding performance between a resin coating material and a resin cement. Two light-cured flowable composites, Protect Liner F and Clearfil Flow FX, were used as coating materials, and two dual-cure composite materials, Panavia F 2.0 and Clearfil DC Core Automix, were used as resin cements. The ultimate tensile strength of each material and the microtensile bond strengths of the bonded specimens of resin coating material and resin cement were measured using a crosshead speed of 1.0 mm/min. Three-way ANOVA (p=0.05) revealed that the highest microtensile bond strength was obtained using a combination of Clearfil Flow FX and Clearfil DC Core Automix, and when the surface of the coating material was treated with ED Primer II. It was strongly suggested that materials with a higher ultimate tensile strength, when used in both resin coating and cementation, could enhance the bond strength between the two. [ABSTRACT FROM AUTHOR]

Burrow MF, Harada N, Kitasako Y, Nikaido T, Tagami J. Seven-year dentin bond strengths of a total- and self-etch system. Eur J Oral Sci 2005; 113: 265–270.© Eur J Oral Sci, 2005 The aim of this study was to determine the durability of tensile bond strengths of a conventional 3-step bonding system (Superbond D-liner Plus) and a self-etching priming bonding system (Clearfil Liner Bond II) to bovine dentin over a 7 yr period. Superficial bovine dentin finished with 600-grit SiC paper was bonded with one of the two adhesive materials. A 4 mm diameter area was bonded, covered with resin composite and stored in 37°C deionized water containing gypsum chips and 0.4% sodium azide as an antibacterial. Bonds were stressed in tension at a crosshead speed of 1 mm min−1. Mean bond strengths were observed at 1 d, at 1, 3, and 6 months, and at 1, 2, 3, 6 and 7 yr. Ten specimens were tested for the first 3 yr and 15 specimens were tested for 6 and 7 yr. The bond strength of Superbond D-liner Plus significantly decreased over the 7 yr period, whereas Liner Bond II showed a slight but, insignificant, decrease. The fracture mode changed with time for Superbond D-liner Plus, but not for Liner Bond II. It was concluded that systems which use a strong acid for demineralizing the dentin may show greater deterioration of the bond to dentin compared with a self-etching priming system. [ABSTRACT FROM AUTHOR]