Effect of indenter material on reliability of all-ceramic crowns
| Autor: | Van P. Thompson, Gerson Bonfante, Nelson R.F.A. Silva, Paulo G. Coelho, Guilherme B. Valverde, Estevam A. Bonfante, Fabio Cesar Lorenzoni |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Dental Stress Analysis
Ceramics Materials science medicine.medical_treatment Biomedical Engineering Modulus Fractography 02 engineering and technology Composite Resins Crown (dentistry) Biomaterials 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine stomatognathic system Tungsten carbide Materials Testing medicine Dental Restoration Failure Ceramic Composite material Elastic modulus Crowns Reproducibility of Results Stiffness 030206 dentistry Epoxy 021001 nanoscience & nanotechnology Dental Porcelain body regions chemistry Mechanics of Materials visual_art FRACTOGRAFIA visual_art.visual_art_medium medicine.symptom 0210 nano-technology |
| Zdroj: | Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP |
| Popis: | 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 Y-TZP 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). |
| Databáze: | OpenAIRE |
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