Flexural strength and crystalline stability of a monolithic translucent zirconia subjected to grinding, polishing and thermal challenges
| Autor: | Gisele Maria Correr, Marina R. Kaizer, Carla Castiglia Gonzaga, Raisa Hintz De Souza, Yu Zhang, Ana Beatriz Franco Fernandes, Alysson Nunes Diógenes, Carolina Elisa Pereira Borges |
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| Rok vydání: | 2021 |
| Předmět: |
010302 applied physics
Materials science Process Chemistry and Technology Polishing Diamond 02 engineering and technology Surface finish engineering.material 021001 nanoscience & nanotechnology 01 natural sciences Article Surfaces Coatings and Films Electronic Optical and Magnetic Materials Grinding Autoclave Flexural strength Grind 0103 physical sciences Materials Chemistry Ceramics and Composites engineering Cubic zirconia Composite material 0210 nano-technology |
| Zdroj: | Ceram Int |
| ISSN: | 0272-8842 |
| Popis: | The objective of this study is to investigate the magnitude of structural degradation of a monolithic translucent zirconia caused by clinically relevant grinding and polishing procedures, when associated or not with low temperature degradation (LTD), induced by accelerated hydrothermal aging using autoclave or thermocycling Ninety disks (Ø12 × 1 mm) were prepared from dental zirconia for monolithic restorations (Vipi Block Zirconn Translucent, Vipi). The specimens were divided into 3 groups (n = 30) according to surface treatment: As Sintered (untreated), Grind (diamond bur), Grind + Polish (diamond bur + polish); and then subdivided according to aging method (n = 10): Baseline (no aging), Autoclave (134°C, 2.2 kgf/cm(2) pressure for 5 h), and Thermocycling (200,000 cycles, 5°C and 55°C, for 15 s each). Roughness, biaxial flexural strength and percentage of monoclinic phase were evaluated. Regarding surface treatment, the Grind group presented higher roughness and greater flexural strength compared to As Sintered group, while Grind + Polish showed intermediate roughness and flexural strength similar to Grind group. Aging had little effect on roughness, but yielded a significant reduction in flexural strength. Tetragonal to monoclinic phase transformation was observed in all groups, caused by both mechanical stresses (grinding and polishing) and LTD, which was similarly induced by the traditional autoclave method, as well as the thermocycling method The use of diamond burs to grind zirconia surface may result in deleterious effects on the surface quality of monolithic zirconia restorations, yet has a potential toughening effect by phase transformation. However, when zirconia is exposed to LTD, regardless of the surface treatment, degradation of the surface quality and strength are observed. |
| Databáze: | OpenAIRE |
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