Shear vs. tensile bond strength of resin composite bonded to ceramic.
Since the mode of failure of resin composites bonded to ceramics has frequently been reported to be cohesive fracture of either ceramic or resin composite rather than separation at the adhesive interface, this study was designed to question the validity of shear bond strength tests. The reasons for such a failure mode are identified and an alternative tensile bond strength test evaluated. Three configurations (A, conventional; B, reversed; and C, all composite) of the cylinder-on-disc design were produced for shear bond strength testing. Two-dimensional finite element stress analysis (FEA) was carried out to determine qualitatively the stress distribution for the three configurations. A tensile bond strength test was designed and used to evaluate two ceramic repair systems, one using hydrofluoric acid (HF) and the other acidulated phosphate fluoride (APF). Results from the shear bond strength tests and FEA showed that this particular test has as its inherent feature the measurement of the strength of the base material rather than the strength of the adhesive interface. In the tensile test, failure invariably occurred in the adhesive layer, with HF and APF showing a similar ability to improve the bond of resin composite to ceramic. It is concluded that the tensile bond strength test is more appropriate for evaluating the adhesive capabilities of resin composites to ceramics.
Della Bona
A
A
Department of Restorative Dentistry, University of Sheffield, United Kingdom.
van Noort
R
R
D000149:Acidulated Phosphate Fluoride; D000268:Adhesiveness; D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry*; D003722:Dental Alloys / Q000737:chemistry*; D001840:Dental Bonding; D003776:Dental Porcelain / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000379:methods*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006858:Hydrofluoric Acid; D008422:Materials Testing / Q000379:methods; D015203:Reproducibility of Results; D019279:Resin Cements; D012821:Silanes; D013718:Tensile Strength
D003188:Composite Resins; D003722:Dental Alloys; D017220:Dentin-Bonding Agents; D019279:Resin Cements; D012821:Silanes; D003776:Dental Porcelain; C073466:Prisma APH; D000149:Acidulated Phosphate Fluoride; C047040:Vita VMK 68; D006858:Hydrofluoric Acid