Dimensional changes from the sintering process and fit of Y-TZP copings: Micro-CT analysis

Author(s)

Edwards Rezende, Carlos Eduardo ^{[1, 2]} ; Sanches Borges, Ana Flavia ^[3] ; Macedo, Rander Moreira ^[1] ; Rubo, Jose Henrique ^[2] ; Griggs, Jason Alan ^[4]

Affiliation

^[1] Positivo Univ, Dent Sch, Postgrad Program Clin Dent, 5300 Pedro Viriato Parigot de Souza Rd, BR-81280330 Curitiba, PR - Brazil

^[2] Univ Sao Paulo, Bauru Sch Dent, Dept Prosthodont, Alameda Octavio Pinheiro Brisolla 9-75, BR-17012901 Bauru, SP - Brazil

^[3] Univ Sao Paulo, Bauru Sch Dent, Dept Operat Dent Endodont & Dent Mat, Alameda Octavio Pinheiro Brisolla 7-35, BR-17012901 Bauru, SP - Brazil

^[4] Univ Mississippi, Med Ctr, Dept Biomed Mat Sci, 2500 North State St, Jackson, MS 39216 - USA

• Document type: Journal article
• Source: Dental Materials; v. 33, n. 11, p. E405-E413, NOV 2017.
• Web of Science Citations: 2

Abstract

Objective. To evaluate the dimensional changes from the sintering process of Y-TZP and relate them to the fit of zirconia copings. Methods. The sintering shrinkage rate (SSR) was obtained from the measurement of geometric specimens (4 x 4 x 2 mm). Thirty-six zirconia copings made using CAD/CAM were equally divided into three groups (n = 12): ZMAX - IPS e. max ZirCAD (Ivoclar Vivadent, Liechtenstein); ZYZ - InCeram YZ (Vita Zahnfabrik, Germany); and ZK - Zirklein (Zirklein, Brazil). The copings were scanned in micro-CT before and after sintering so that SSR was obtained. The SSR of geometrical specimens and copings was compared to each other and those the manufacturers reported (ANOVA-2 and Tukey, p <=.05). The copings were settled on an abutment and taken to the micro-CT to evaluate their marginal and internal fit. The data enabled the statistical comparison (ANOVA-2 and Tukey, p <=.05) between groups and measurement sites and between the fit obtained with that stipulated by the CAD/CAM software (80 mu m) (Dunnett test, p <=.05). Results. All groups showed statistical differences between the SSR the manufacturer reported and those obtained experimentally and between the SSR of the geometric specimens and copings. In general, the SSR of the copings showed no uniformity. There was no statistical difference among the groups for marginal fit, with differences only for internal fit and between the different regions measured. The fit obtained experimentally differed from the internal space determined in the CAD/CAM software. Significance. The lack of uniformity of sintering shrinkage might lead to a non-uniform internal fit of Y-TZP copings. (C) 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 11/18061-0 - Structural and mechanical analysis and copings of experimental zirconia for use CAD/CAM system
• Grantee: Ana Flávia Sanches Borges
• Support Opportunities: Regular Research Grants
• FAPESP's process: 13/10021-5 - Reliability, failure modes and fit of prosthetic single crowns
• Grantee: José Henrique Rubo
• Support Opportunities: Regular Research Grants