Publication date: December 2018
Source: The Journal of Prosthetic Dentistry, Volume 120, Issue 6
Author(s): Min-Gyeong Nam, Mi-Gyoung Park
Abstract
Statement of problem
Surface glazing and low-temperature degradation (LTD) can affect the mechanical properties of zirconia, which is used to fabricate monolithic ceramic crowns.
Purpose
The purpose of this in vitro study was to assess the changes in flexural strength of monolithic ceramic crowns fabricated from translucent zirconia due to surface glazing and LTD.
Material and methods
Sixty plates of zirconia (25×4×1.2 mm) were milled and sintered. They were classified into 4 groups according to glazing and LTD (n=15): control, glazing, LTD, and LTD after glazing. A 3-point flexural test was performed with a universal testing machine. X-ray diffraction (XRD) was used to observe changes in the crystal structures of each group, and field emission scanning electron microscopy was used to observe the sizes of the crystal grains. Two-way analysis of variance was used to evaluate the results of the flexural strength tests, and the Tukey honestly significant difference test was performed for post hoc analysis (α=.05).
Results
The flexural strength showed significant differences due to glazing (P<.01). No significant differences were found due to LTD (P>.05). The crystal grain size increased with decreasing flexural strength of the specimens. XRD showed monoclinic phases in the groups subjected to LTD.
Conclusions
Glazing significantly reduced the flexural strength of translucent zirconia. LTD decreased the flexural strength of glazed translucent zirconia, but not to a significant extent.
from OroFacial via a.sfakia on Inoreader https://ift.tt/2QQLywC
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.