Wuthipong Luesak. The effect of film thickness of two adhesive resin cements on shear bond strength of Ni-Cr alloy to bovine dentine. Master's Degree(Prosthodontics). Mahidol University. : Mahidol University, 2005.
The effect of film thickness of two adhesive resin cements on shear bond strength of Ni-Cr alloy to bovine dentine
Abstract:
Film thickness of luting cement is one of the critical factors for clinical success of the fixed prostheses restoration. The thickness of cement layer between the prostheses and tooth may affect the bond strength. Nowadays, adhesive resin cement is often used in patient because it has some advantages over the conventional cement. The purpose of this study was to evaluate the effect of film thickness of two adhesive resin cements on the shear bond strength of base metal alloy to bovine dentine. The shear bond testing was performed to evaluate between 2 adhesive resin cements and level of 4 film thickness. Specimens of 120 bovine dentine were divided into eight groups (n = 15) and bonded to Ni-Cr casting alloy cylinders ( 5×3mm.) with either Panavia F or Super Bond C&B at film thickness of 50, 100, 150, and 200 µm, then stored in distilled water at 37±2oC for 24 hours prior to testing. The shear test was applied to the specimen using a chisel-shaped bar compressed perpendicular and contacted to dentine site with a crosshead speed of 0.5 mm/min until failure occurred. All fractured specimens were investigated with SEM for their mode of failure. The higher shear bond strength of Panavia F (9.32±2.40 MPa) and Super Bond C&B (7.10±2.70 MPa) were recorded in 100 µm. The lower shear bond strength of Panavia F (4.02±1.44 MPa) and Super Bond C&B (5.01±1.38 MPa) were recorded in 200 and 50 µm, respectively. The mean shear bond strengths of Panavia F were not significantly different when the film thickness were ≤ 150 µm (P>0.05). For Super Bond C&B, the mean shear bond strengths were not significantly different at all level of film thickness (P>0.05). The complex failure and more voids were found in the thicker film thickness and their shear bond strength values tended to decrease when the film thickness was increased.""