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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

The mechanical behavior of high-translucent monolithic zirconia after adjustment and finishing procedures and artificial aging

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Hatanaka, Gabriel Rodrigues [1] ; Polli, Gabriela Scatimburgo [1] ; Adabo, Gelson Luis [1]
Total Authors: 3
[1] Sao Paulo State Univ UNESP, Sch Dent, Dept Dent Mat & Prosthodont, Araraquara, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: JOURNAL OF PROSTHETIC DENTISTRY; v. 123, n. 2, p. 330-337, FEB 2020.
Web of Science Citations: 0

Statement of problem. How occlusal adjustments and finishing of high-translucent monolithic zirconia restorations affect their mechanical behavior is unclear. Purpose. The purpose of this in vitro study was to investigate the effect of grinding, and hydrothermal degradation on the roughness, flexural strength, and reliability of fully stabilized zirconia (FSZ) and partially stabilized zirconia (PSZ) for monolithic restorations. Material and methods. Specimens of PSZ and FSZ were divided into 5 groups: control (Ctrl); those ground by using coarse diamond rotary instrument (Gr); those that underwent grinding, polishing (diamond rubber), and glazing (GrPolGl); those that underwent grinding and glazing GrGl); and those that underwent grinding and polishing (GrPol). These groups were subdivided into nonaged and hydrothermally aged in autoclave (134 degrees C, 200 kPa). Three-point bend tests flexural strength {[}FS]) were performed (n=30), and roughness (Ra) was measured by using a contact profilometer (n=30). The Weibull moduli were obtained from the FS data. The intergroup FS was analyzed by the Kruskal-Wallis test and Student-Newman-Keuls method, and the intra- group FS, Mann-Whitney tests (alpha=.05). Results. The median FS for PSZ (MPa) for the aforementioned groups is as follows: Gr (1147.8)=GrPol 1210.3)>GrPolGl (815.6)>GrGI (569.7)=Ctrl (583.0). The FS for FSZ (MPa) for the aforementioned groups is as follows: GrPolGl (404.2)=GrGl (427.0)<Ctrl (484.8)=Gr (435.9)=GrPol (443.7). Grinding led to high roughness values. The Weibull modulus was most influenced by glaze treatment. Conclusions. Monolithic zirconia exhibited a different mechanical behavior after adjustment procedures and hydrothermal aging. Grinding increased the roughness, and polishing reduced the roughness of the ground surface. FS improvement by finishing depended on the type of zirconia. Glazing smoothened the surface but tended to decrease the FS. Aging of PSZ improved the FS except in the control and glazed groups, whereas FSZ was not affected by aging, except in the GrGl group. (AU)

FAPESP's process: 16/09640-0 - Mechanical and microstructural characterization of monolithic zirconia and lithium disilicate and study of step stress accelerated life testing of crowns with different ceramic thickness
Grantee:Gelson Luis Adabo
Support Opportunities: Regular Research Grants