Produção Nacional
Revisado por pares
Opaque Layer Firing Temperature and Aging Effect on the Flexural Strength of Ceramic Fused to Cobalt‐Chromium Alloy
2010; Wiley; Volume: 19; Issue: 6 Linguagem: Inglês
10.1111/j.1532-849x.2010.00600.x
ISSN1532-849X
AutoresLuana Marotta Reis de Vasconcellos, Leonardo Buso, Geraldo Henrique Leão Lombardo, Rodrigo Othávio de Assunção e Souza, Lafayette Nogueira Júnior, Marco Antônıo Bottıno, Mutlu Özcan,
Tópico(s)Orthopaedic implants and arthroplasty
ResumoTo evaluate the effect of the opaque layer firing temperature and mechanical and thermal cycling on the flexural strength of a ceramic fused to commercial cobalt-chromium alloy (Co-Cr). The hypotheses were that higher opaque layer temperatures increase the metal/ceramic bond strength and that aging reduces the bond strength.Metallic frameworks (25 x 3 x 0.5 mm(3); ISO 9693) (N = 60) were cast in Co-Cr and airborne-particle abraded (Al(2)O(3): 150 mum) at the central area of the frameworks (8 x 3 mm(2)) and divided into three groups (N = 20), according to the opaque layer firing temperature: Gr1 (control)-900 degrees C; Gr2-950 degrees C; Gr3-1000 degrees C. The opaque ceramic (Opaque, Vita Zahnfabrick, Bad Säckingen, Germany) was applied, and the glass ceramic (Vita Omega 900, Vita Zahnfabrick) was fired onto it (thickness: 1 mm). While half the specimens from each group were randomly tested without aging (water storage: 37 degrees C/24 hours), the other half were mechanically loaded (20,000 cycles; 50 N load; distilled water at 37 degrees C) and thermocycled (3000 cycles; 5 degrees C to 55 degrees C, dwell time: 30 seconds). After the flexural strength test, failure types were noted. The data were analyzed using 2-way ANOVA and Tukey's test (alpha= 0.05).Gr2 (19.41 +/- 5.5 N) and Gr3 (20.6 +/- 5 N) presented higher values than Gr1 (13.3 +/- 1.6 N) (p= 0.001). Mechanical and thermal cycling did not significantly influence the mean flexural strength values (p > 0.05). Increasing the opaque layer firing temperature improved the flexural bond strength values (p < 0.05). The hypotheses were partially accepted.Increasing of the opaque layer firing temperature improved the flexural bond strength between ceramic fused to Co-Cr alloy.
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