J Korean Acad Prosthodont.  2021 Apr;59(2):190-200. 10.4047/jkap.2021.59.2.190.

Effect of coloring liquids on biaxial flexural strength of monolithic zirconia

• Jung C
• Kim MJ
• Kim JH

• KMID: 2515221
• DOI: http://doi.org/10.4047/jkap.2021.59.2.190

Abstract

Purpose
. The aim of this study was to evaluate biaxial flexural strength and hardness of colored monolithic zirconia after dipping in different time intervals of coloring solution.
Materials and Methods
. Disk shaped specimens were prepared from monolithic zirconia (Eclipse V2.0, AMS, Gimpo, Korea). Four experimental groups were categorized (n = 12) due to coloring time (PU (0s); ST (8s); OV (1 min); PS (preshade)), to evaluate biaxial flexural strength and Vickers hardness. After fracture, X-ray diffraction analysis was performed using fractured specimens. Results were analyzed with one-way ANOVA test.
Results
. There was no significant difference between groups in the biaxial flexural strength test. However, in the Vickers hardness test, the group with standard dipping time (ST) showed significantly higher value than the group without dipping in coloring liquid (PU)(P=.038).Also, there was no significant difference in the rest of the groups (P>.05). As a result of X-ray diffraction analysis, specific peaks of tetragonal phase were shown and the volume of monoclinic phase fraction was lower than 25%.
Conclusion
. Although this study has several limitations, coloring liquids had no significant effect on biaxial flexural strength. Vickers hardness was significantly different between the group to which the coloring liquid was applied and the group to which the coloring solution was not applied, but there was no significant difference between the other groups. Also, the flexural strength of monolithic zirconia corresponds to Class 5 of the minimal flexural strength standard according to the use of dental ceramics.

Keyword

Flexural strength; Hardness; Pigmentation; Prosthesis coloring; Zirconia