O L Bezzon1, R F Ribeiro, J M Rollo, S Crosara. 1. Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil. olbezzon@forp.usp.br
Abstract
STATEMENT OF PROBLEM: Because of its pathogenic potential, the importance of the use of beryllium with Ni-Cr alloys must be determined. PURPOSE: This study compared fundamental properties for the clinical use of Ni-Cr alloys, determining the advantage of the addition of beryllium, despite the involved risks. MATERIAL AND METHODS: Two Be-free commercial alloys (Vera Bond II and Wiron 99) and 1 Be-free experimental alloy (E3) with Nb and/or Mo in their formulations and 1 experimental Ni-Cr alloy (E4) with 1.1% Be were submitted to ceramometal bonding resistance, castability, and hardness tests. RESULTS: Analysis of variance showed significant differences (P=.05) between Vera Bond II and Wiron 99 (Be-free) and the E4 alloy for the castability test. Vera Bond II, Wiron 99, and E4 presented higher castability values than E3. There were no statistically significant differences for the ceramometal bonding resistance test. The Kruskal-Wallis test showed significant differences (P=.01) among the alloys with Rockwell 30 T values for the hardness test. CONCLUSION: Within the limitations of this study, the presence of Be in Ni-Cr alloys was not necessary to guarantee the castability and the ceramometal bond resistance of the alloys tested.
STATEMENT OF PROBLEM: Because of its pathogenic potential, the importance of the use of beryllium with Ni-Cr alloys must be determined. PURPOSE: This study compared fundamental properties for the clinical use of Ni-Cr alloys, determining the advantage of the addition of beryllium, despite the involved risks. MATERIAL AND METHODS: Two Be-free commercial alloys (Vera Bond II and Wiron 99) and 1 Be-free experimental alloy (E3) with Nb and/or Mo in their formulations and 1 experimental Ni-Cr alloy (E4) with 1.1% Be were submitted to ceramometal bonding resistance, castability, and hardness tests. RESULTS: Analysis of variance showed significant differences (P=.05) between Vera Bond II and Wiron 99 (Be-free) and the E4 alloy for the castability test. Vera Bond II, Wiron 99, and E4 presented higher castability values than E3. There were no statistically significant differences for the ceramometal bonding resistance test. The Kruskal-Wallis test showed significant differences (P=.01) among the alloys with Rockwell 30 T values for the hardness test. CONCLUSION: Within the limitations of this study, the presence of Be in Ni-Cr alloys was not necessary to guarantee the castability and the ceramometal bond resistance of the alloys tested.