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J Prosthet Dent. 2017 Sep;118(3):422-429. doi: 10.1016/j.prosdent.2016.10.024. Epub 2017 Feb 21.

Effect of hydrothermal treatment on light transmission of translucent zirconias.

Author information

1
Graduate student, Graduate Prosthodontics, Department of Restorative Dentistry, School of Dentistry, University of Washington, Seattle, Wash.
2
Professor, Department of Restorative Dentistry, University of Washington School of Dentistry, Seattle, Wash. Electronic address: akchung@uw.edu.
3
Research Associate Professor, Materials Science and Engineering, University of Washington School of Engineering, Seattle, Wash.
4
MSE Lab Manager, Materials Science and Engineering, University of Washington School of Engineering, Seattle, Wash.
5
Assistant Professor, Biostatistics, Joseph J Zilber School of Public Health, University of Wisconsin, Milwaukee, Wis.
6
Visiting Lecturer, Department of Restorative Dentistry, University of Washington School of Dentistry, Seattle, Wash; and Adjunct Lecturer, Department of Crown and Bridge, School of Life Dentistry at Tokyo, the Nippon Dental University, Tokyo, Japan.
7
Professor, Department of Restorative Dentistry, University of Washington School of Dentistry, Seattle, Wash.

Abstract

STATEMENT OF PROBLEM:

Studies of the light transmission of translucent zirconias after hydrothermal treatment are limited.

PURPOSE:

The purpose of this in vitro study was to evaluate the effect of hydrothermal treatment on the light transmission of translucent zirconias for monolithic restorations.

MATERIAL AND METHODS:

Four commercially available zirconia products, BruxZir Anterior Solid Zirconia (BruxAnt, BA), Lava Plus High Translucency (LPHT), Katana Zirconia Super Translucent (KST), and Katana Zirconia Ultra Translucent (KUT) were assessed and 1 type of lithium disilicate, e.max Press LT (LDLT) was used as a control. Plate specimens, 20×20×1 mm (n=80) for the translucency assessment were sectioned from postsintered zirconia bulk materials and ground with a #400-grit diamond wheel and coolant. The specimens were placed under hydrothermal conditions of 134°C at 0.2 MPa (n=5 per group at 0, 5, 50, and 100 hours). Percentage of total transmittance of light (Tt%) of each specimen was measured using a spectrophotometer with an integrating sphere. X-ray diffraction analyses were used to measure tetragonal-monoclinic phase transformation. Surfaces were examined by scanning electron microscopy and energy dispersive spectrometry. Data were analyzed using 2-way ANOVA followed by the Tukey test (α=.05).

RESULTS:

The Tt% ranged from 6.5% to 28.3%. Group LDLT obtained significantly higher transmittance than other tested groups, whereas groups KST and KUT had significantly higher Tt% than groups BA and LPHT (P<.05). A statistically significant increase in the amount of monoclinic phase was revealed within all translucent zirconia groups (P<.05), and the increase in group LPHT was significantly higher than those of the other 3 translucent zirconias (P<.05). Minimal changes in the percentages of light transmittance were revealed after 100-hour hydrothermal treatment for all tested translucent zirconias and a lithium disilicate glass-ceramic control.

CONCLUSIONS:

Hydrothermal treatment had minimal effects on the translucency of translucent zirconias. The tetragonal-monoclinic phase transformation rate of translucent zirconias was found to be low, except in group LPHT.

PMID:
28238306
DOI:
10.1016/j.prosdent.2016.10.024
[Indexed for MEDLINE]

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