title: Relationship between adhesive thickness and microtensile bond strength.
abstract: This study evaluated the effect of the thickness of the adhesive resin layer of two commercially available resin bonding systems on bond strengths (Single Bond and Liner Bond 2V). The adhesive of Single Bond contains ethanol and water as solvents and is applied using the moist-bonding technique. The adhesive of Liner Bond 2V contains no solvents and is applied after a self-etching primer treatment. Forty-six caries-free molars were ground flat to expose the dentin surface and polished with #800-grit silicon carbide paper under running water. A vinyl tape punched with a 6 mm diameter hole was then placed on the dentin surface to demarcate the area for bonding. The thickness of the adhesive resin layer was varied by stacking an increasing numbers of vinyl tapes together. The teeth were randomly divided into two groups and treated with either Clearfil Liner Bond 2V or Single Bond. They were further divided into subgroups according to the number of tapes placed on the dentin surface. After the bonding procedures the teeth were incrementally restored with Clearfil AP-X resin composite, building a 5 mm high crown to produce sufficient bulk for the microtensile bond test and stored in tap water at 37 degrees C for 24 hours. The teeth were then sectioned along their long axis into 0.7 mm thick slabs and trimmed for the microtensile bond test using a super-fine diamond bur. The thickness of the adhesive resin layer was then measured with a light microscope and the slabs tested in tension at a crosshead speed of 1 mm/minute. The results were subjected to statistical analysis by a one-way analysis of variance and linear regressions with 95% confidence intervals. The thickness of the Clearfil Liner Bond 2V adhesive layer ranged from 5 mm-1500 mm, and for Single Bond, it varied from < 7.5 mm-430 mm. For Clearfil Liner Bond 2V, bond strengths increased significantly as the thickness of bonding layer increased (p < 0.05). However, the bond strengths of the Single Bond decreased significantly with increased thickness of the bonding layer (p < 0.05).
authors.affiliation: Cariology and Operative Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, 5-45 Yushima, 1-chome, Bunkyo-ku, Tokyo 113-8549, Japan.
authors.forename: L
authors.initials: L
authors.lastname: Zheng
authors.forename: P N
authors.initials: PN
authors.lastname: Pereira
authors.forename: M
authors.initials: M
authors.lastname: Nakajima
authors.forename: H
authors.initials: H
authors.lastname: Sano
authors.forename: J
authors.initials: J
authors.lastname: Tagami
mesh_terms: D000134:Acid Etching, Dental; D000269:Adhesives / Q000737:chemistry*; D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D017554:Carbon Compounds, Inorganic; D003188:Composite Resins / Q000737:chemistry*; D016001:Confidence Intervals; D001840:Dental Bonding; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D000431:Ethanol / Q000737:chemistry; D006801:Humans; D016014:Linear Models; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008963:Molar; D019279:Resin Cements / Q000737:chemistry; D017655:Silicon Compounds; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties; D013718:Tensile Strength; D014867:Water / Q000737:chemistry
chemical_list: D000269:Adhesives; D017554:Carbon Compounds, Inorganic; C112828:Clearfil AP-X; C112274:Clearfil Liner Bond 2; D003188:Composite Resins; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D019279:Resin Cements; D017655:Silicon Compounds; D012997:Solvents; C115612:single bond; D014867:Water; D000431:Ethanol; D017438:Bisphenol A-Glycidyl Methacrylate; C022088:silicon carbide