Korean J Dent Mater.  2020 Dec;47(4):221-234. 10.14815/kjdm.2020.47.4.221.

Effect of sintering condition and aging on hardness and optical properties of monolithic zirconia

• Kong MC
• Park MG

• KMID: 2511998
• DOI: http://doi.org/10.14815/kjdm.2020.47.4.221

Abstract

The purpose of this study was to examine the effect of hardness and optical properties of dental zirconia in accordance to sintering condition and aging. 10.0 mm×10.0 mm×1.5 mm zirconia specimens were prepared using Luxen Enamel E2. According to aging, zirconia specimens were sintered under fifteen different conditions. Specimens were divided into six subgroup and sintered with various durations (4 h, 5 h, 6 h, 7 h, and 12 h) at the various maximum temperature (1,500℃, 1,530℃, and 1,560℃). The hardness was measured four times per specimen using a Micro Vickers hardness tester, CIE L * , a * , b * values of each specimen were measured using a spectrophotometer and the TP values were calculated for translucency comparison. In the specimen with aging, there was a difference in hardness according to the sintering temperature, but there was no difference in hardness according to the sintering time. In the specimen with aging, as sintering temperature increased, CIE L * , a * , b * values decreased, resulting in a decrease in brightness and tendency of green and blue trends. In the specimen with aging, there was no change in L * value with decreasing sintering time and as sintering time decreased, CIE a * , b * values decreased, resulting in tendency of green and blue. In the specimen with aging, even if the sintering time decreases from 12 hours to 5 hours, there was no reduce in TP values.

Keyword

Monolithic zirconia; Hardness; Optical properties; Aging; Sintering condition