title: Wear resistance of a pressable low-fusing ceramic opposed by dental alloys.
abstract: Dental alloys have increasingly replaced by dental ceramics in dentistry because of aesthetics. As both dental alloys and ceramics can be present in the oral cavity, the evaluation of the wear resistance of ceramics opposed by dental alloys is important. The aim of the present study was to evaluate wear resistance of a pressable low-fusing ceramic opposed by dental alloys as well as the microhardness of the alloys and the possible correlation of wear and antagonist microhardness. Fifteen stylus tips samples of pressable low-fusing ceramic were obtained, polished and glazed. Samples were divided into three groups according to the disk of alloy/metal to be used as antagonist: Nickel-Chromium (Ni-Cr), Cobalt-Chromium (Co-Cr) and commercially pure titanium (cp Ti). Vickers microhardness of antagonist disks was evaluated before wear tests. Then, antagonist disks were sandblasted until surface roughness was adjusted to 0.75μm. Wear tests were performed at a speed of 60 cycles/min and distance of 10mm, in a total of 300,000 cycles. Before and after wear tests, samples were weighted and had their profile designed in an optical comparator to evaluate weight and height loss, respectively. Ni-Cr and cp Ti caused greater wear than Co-Cr, presenting greater weight (p=.009) and height (p=.002) loss. Cp Ti microhardness was lower than Ni-Cr and Co-Cr (p<.05). There is a positive correlation between weight and height loss (p<.05), but weight (p=.204) and height (p=.05) loss are not correlated to microhardness. The results suggest that pressable low-fusing ceramic presents different wear according to the dental alloy used as antagonist and the wear is not affected by antagonist microhardness.
authors.affiliation: Department of Dental Materials and Prosthodontics, Dental School of Ribeirão Preto, University of São Paulo, São Paulo, Brazil. Av. do Café, s/n, 14040-904 Ribeirão Preto, SP, Brazil.. Electronic address: adriclalf@forp.usp.br.
authors.forename: Adriana Cláudia Lapria
authors.initials: ACL
authors.lastname: Faria
authors.affiliation: Department of Dental Materials and Prosthodontics, Dental School of Ribeirão Preto, University of São Paulo, São Paulo, Brazil. Av. do Café, s/n, 14040-904 Ribeirão Preto, SP, Brazil.
authors.forename: André Almeida
authors.initials: AA
authors.lastname: de Oliveira
authors.affiliation: Department of Dental Materials and Prosthodontics, Dental School of Ribeirão Preto, University of São Paulo, São Paulo, Brazil. Av. do Café, s/n, 14040-904 Ribeirão Preto, SP, Brazil.
authors.forename: Érica
authors.initials: É
authors.lastname: Alves Gomes
authors.affiliation: Department of Dental Materials and Prosthodontics, Dental School of Ribeirão Preto, University of São Paulo, São Paulo, Brazil. Av. do Café, s/n, 14040-904 Ribeirão Preto, SP, Brazil.
authors.forename: Renata Cristina
authors.initials: RC
authors.lastname: Silveira Rodrigues
authors.affiliation: Department of Dental Materials and Prosthodontics, Dental School of Ribeirão Preto, University of São Paulo, São Paulo, Brazil. Av. do Café, s/n, 14040-904 Ribeirão Preto, SP, Brazil.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Faria Ribeiro
mesh_terms: D002516:Ceramics; D003722:Dental Alloys; D006244:Hardness; D008422:Materials Testing; D055595:Mechanical Phenomena
chemical_list: D003722:Dental Alloys
keywords: Ceramics; Dental alloys; Dental restoration wear; Hardness tests