Effect of indenter material on reliability of all-ceramic crowns

Autor(es)

Lorenzoni, Fabio C. ^{[1, 2]} ; Bonfante, Estevam A. ^[3] ; Valverde, Guilherme B. ^[4] ; Coelho, Paulo G. ^[5] ; Bonfante, Gerson ^[3] ; Thompson, Van P. ^[6] ; Silva, Nelson R. F. A. ^[7]

Afiliação do(s) autor(es)

^[1] Unigran Univ, Sch Dent, Dept Prosthodont, Dourados, MS - Brazil

^[2] Lorenzoni Educ Inst, Ponta Poru, MS - Brazil

^[3] Univ Sao Paulo, Bauru Sch Dent, Dept Prosthodont & Periodontol, Bauru, SP - Brazil

^[4] Tufts Sch Dent Med, Adv Educ Esthet & Operat Dent, Boston, MA - USA

^[5] NYU, Hansjorg Wyss Dept Plast Surg Mech & Aerosp Engn, Dept Biomat, New York, NY - USA

^[6] Kings Coll London, Fac Dent, Dept Tissue Engn & Biophoton, London - England

^[7] Univ Fed Minas Gerais, FO UFMG, Dept Restorat Dent, Belo Horizonte, MG - Brazil

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS; v. 108, AUG 2020.
• Citações Web of Science: 0

Resumo

Objectives: Controversy exists about whether the elastic modulus (E) mismatch between the loading indenter and ceramic materials influences fatigue testing results. The research hypotheses were that for porcelain veneered YTZP crowns 1) A low modulus Steatite indenter (SB) leads to higher fatigue reliability compared to a high modulus tungsten carbide indenter (WC); 2) Different surface damage patterns are expected between low and high modulus indenters after sliding contact fatigue testing. All ceramic crowns will exhibit similar step-stress accelerated life testing (SSALT) contact fatigue reliability (hypothesis 1) and failure characteristics (hypothesis 2) when using high stiffness tungsten carbide (WC, E = 600 GPa) vs. enamel like steatite (SB, E = 90 GPa) indenters. Methods: Manufacturer (3M Oral Care) prepared Y-TZP-veneered all-ceramic molar crowns were bonded to aged resin composite reproductions of a standard tooth preparation and subjected to mouth-motion SSALT fatigue (n = 18 per indenter type). Failure was defined either as initial inner cone crack (IC), or final fracture (FF) when porcelain fractured (chipping). Selected IC specimens that did not progress to FF were embedded in epoxy resin and sectioned for fractographic analysis. Results: The distribution of failures across the load and cycle profiles lead to similar calculated Weibull Use Level Probability Plots with overlap of the 2-sided 90% confidence bounds. The calculated reliability for IC and FF was equivalent at a mission of 300 N or 700 N load and 50,000 cycles, although the WC indenter had a trend for lower reliability for IC at 700 N. Both indenters produced similar patterns of wear and cracking on crown surfaces. Fractographic landmarks showed competing failure modes, but sliding contact partial inner cone cracks were the most dominant for both groups. Significance: The more compliant Steatite indenter had similar veneered crown fatigue reliability and failure modes to those found with use of a high stiffness tungsten carbide indenter (hypotheses 1 and 2 rejected). (AU)

• Processo FAPESP: 12/19078-7 - Desenvolvimento e processamento de compósito de Al2O3-ZrO2 para próteses monolíticas CAD/CAM: efeito do envelhecimento na resistência à flexão biaxial
• Beneficiário: Estevam Augusto Bonfante
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores