Next Article in Journal
Study of the Mechanical Properties of Highly Efficient Heat Exchange Tubes
Previous Article in Journal
Influence of Minor Cr Additions on Crystal Growth in Rapidly Solidified Al-20Zn Alloys
Open AccessArticle

Effect of Thermocycling, Surface Treatments and Microstructure on the Optical Properties and Roughness of CAD-CAM and Heat-Pressed Glass Ceramics

1
Department of Dental Prostheses Technology, Universitatea de Medicina si Farmacie Victor Babes, Timisoara, 300041 Timisoara, Romania
2
Department of Oral Reahabilitation, Universitatea de Medicina si Farmacie Victor Babes, Timisoara, 300041 Timisoara, Romania
3
National Institute for Research and Development in Electrochemistry and Condensed Matter, 300569 Timisoara, Romania
*
Author to whom correspondence should be addressed.
Materials 2020, 13(2), 381; https://doi.org/10.3390/ma13020381
Received: 14 December 2019 / Revised: 6 January 2020 / Accepted: 7 January 2020 / Published: 14 January 2020
Dental ceramic restorations are widely spread nowadays due to their aesthetics and biocompatibility. In time, the colour and structure of these ceramic materials can be altered by aging processes. How does artificial aging affect the optical and surface roughness of ceramics? This study aims to assess the effect of thermocycling, surface treatments and microstructure upon translucency, opalescence and surface roughness on CAD-CAM and heat-pressed glass-ceramic. Forty-eight samples (1.5 mm thickness) were fabricated from six types of A2 MT ceramic: heat-pressed and milled glass-ceramic (feldspathic, lithium disilicate and zirconia reinforced lithium silicate). The samples were obtained respecting the manufacturer’s instructions. The resulted surfaces (n = 96) were half glazed and half polished. The samples were subjected to thermocycling (10,000 cycles) and roughness values (Ra and Rz), colour coordinates (L*, a*, b*) and microstructural analyses were assessed before and after thermocycling. Translucency (TP) and opalescence (OP) were calculated. Values were statistically analysed using ANOVA test (one way). TP and OP values were significantly different between heat-pressed and milled ceramics before and also after thermocycling (p < 0.001). Surface treatments (glazing and polishing) had a significant effect on TP and OP and surface roughness (p < 0.05). The heat-pressed and milled zirconia reinforced lithium silicate glass-ceramic experienced a loss in TP and OP. Ra and Rz increased for the glazed samples, TP and OP decreased for all the samples after thermocycling. Microstructural analyse revealed that glazed surfaces were more affected by the thermocycling and especially for the zirconia reinforced lithium silicate ceramic. Optical properties and surface roughness of the chosen ceramic materials were affected by thermocycling, surface treatments and microstructural differences. The least affected of the ceramics was the lithium disilicate ceramic heat-pressed polished and glazed. View Full-Text
Keywords: thermocycling; translucency; opalescence; heat-pressed ceramics; milled ceramics; surface roughness thermocycling; translucency; opalescence; heat-pressed ceramics; milled ceramics; surface roughness
Show Figures

Figure 1

MDPI and ACS Style

Vasiliu, R.-D.; Porojan, S.D.; Bîrdeanu, M.I.; Porojan, L. Effect of Thermocycling, Surface Treatments and Microstructure on the Optical Properties and Roughness of CAD-CAM and Heat-Pressed Glass Ceramics. Materials 2020, 13, 381.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop