[The shear bond strength of porcelain and base metal alloys for metal-ceramic crown (VII)].
The popularity of the base metal alloys has increased in the past decade because of their lower price, high tensile strength and high elastic modulus. Several factors are critical in ensuring successful bonding: the matching of the thermal coefficients of expansion and constraction of the porcelain and metal, the metallurgic composition of the alloy and the pretreatment procedures used in preparation of the metal substructure. Two ceramic base alloys (one alloy contains beryllium, another without) were studied. The surface textures were created by 50 microns, 100 microns aluminum oxide sandblasting, carbide bur, carborundum point and disk upon two base alloys, Rexillium III and Wiron 88. The purposes of this investigation were to determine how these variations in surface texture affect the bond strength of the two ceramo-metal alloy systems. The following results were obtained: 1. Statistics revealed that bond strength was not significantly increased with surface roughness (p > 0.05). 2. The shear bond strength for variable pretreatment methods were in the following sequence: 100 microns Al2O3 sandblasting, carbide bur, 50 microns Al2O3 sandblasting, carborundum point, disk. 3. The Rexillium III alloy had a significantly higher bond strength than Wiron 88 alloy (p < 0.05). 4. The Noritake porcelain showed a significantly higher bond strength than Biobond porcelain (p < 0.05). 5. The fracture site was cohesive and adhesive mode treated with 50 microns Al2O3, 100 microns Al2O3, carbide bur. But carborundum point and disk was adhesive mode.
Hsu
C S
CS
Department of Prosthodontics, School of Dentistry, Kaohsiung Medical College, Taiwan, Republic of China.
Wu
Y T
YT
D003442:Crowns; D003722:Dental Alloys; D003776:Dental Porcelain; D006801:Humans; D013718:Tensile Strength
D003722:Dental Alloys; D003776:Dental Porcelain