title: Shear bond strength of dental porcelains to nickel-chromium alloys.
abstract: The continuous technological advance and increasing availability of new base metal alloys and ceramic systems in the market, coupled to the demands of daily clinical practice, have made the constant evaluation of the bond strength of metal/porcelain combinations necessary. This study evaluated the metal/porcelain shear bond strength of three ceramic systems (Duceram, Williams and Noritake) in combination with three nickel-chromium (Ni-Cr) alloys (Durabond, Verabond and Viron). Thirty cast cylinder specimens (15 mm high; 6 mm in diameter) were obtained for each alloy, in a way that 10 specimens of each alloy were tested with each porcelain. Bond strength was measured with an Emic screw-driven mechanical testing machine by applying parallel shear forces to the specimens until fracture. Shear strength was calculated using the ratio of the force applied to a demarcated area of the opaque layer. Mann-Whitney U test was used for statistical analysis of the alloy/ceramic combinations (p<0.05). Viron/Noritake had the highest shear bond sregnth means (32.93 MPa), while Verabond/Duceram (16.31 MPa) presented the lowest means. Viron/Noritake differed statistically from other combinations (p<0.05). Viron/Duceram had statistically significant higher bond strengths than Verabond/Duceram, Verabond/Williams and Durabond/Noritake (p<0.05). It was also found significant difference (p<0.05) between Verabond/Noritake, Verabond/Duceram and Durabond/Noritake. No statistically significant difference (p>0.05) were observed among the other combinations. In conclusion, the Noritake ceramic system used together with Viron alloy presented the highest resistance to shear forces, while Duceram bonded to Verabond presented the lowest bond strength. Viron/Duceram and Verabond/Noritake provided intermediate results. The combinations between the Williams ceramic system and Ni-Cr alloys had similar shear strengths among each other.
authors.affiliation: Department of Occlusion, Fixed Prosthesis and Dental Materials, Faculty of Dentistry, Federal University of Uberlândia, Uberlândia, MG, Brazil. eduma2@triang.com.br
authors.forename: Ricardo Alves
authors.initials: RA
authors.lastname: do Prado
authors.forename: Heitor
authors.initials: H
authors.lastname: Panzeri
authors.forename: Alfredo Julio
authors.initials: AJ
authors.lastname: Fernandes Neto
authors.forename: Flávio Domingues
authors.initials: FD
authors.lastname: das Neves
authors.forename: Marlete Ribeiro
authors.initials: MR
authors.lastname: da Silva
authors.forename: Gustavo
authors.initials: G
authors.lastname: Mendonça
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D002858:Chromium Alloys / Q000737:chemistry*; D003722:Dental Alloys / Q000737:chemistry*; D001840:Dental Bonding; D003735:Dental Casting Technique; D045662:Dental Etching; D003776:Dental Porcelain / Q000737:chemistry*; D005898:Glass / Q000737:chemistry; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D033081:Shear Strength; D013314:Stress, Mechanical; D013499:Surface Properties
chemical_list: D002858:Chromium Alloys; D003722:Dental Alloys; C095718:Duceram; D003776:Dental Porcelain; D000537:Aluminum Oxide