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Friday, October 12, 2012
Zirconia crowns and wear.
A discussion on the Internet Dental Forum brought up the discussion of the wear of opposing teeth when placing a Zirconia crown. I place a lot of Zirconia crowns in the 1st and 2nd molar regions because of their strength and better (not great) esthetics compared to gold.
Advanced Prosthodontics, Graduate School of Clinical Dentistry, Korea University, Seoul, Korea.
This study was conducted to evaluate clinical validity of a zirconia full-coverage crown by comparing zirconia's wear capacity over antagonistic teeth with that of feldspathic dental porcelain.
MATERIALS AND METHODS:
THE SUBJECT GROUPS WERE DIVIDED INTO THREE GROUPS: the polished feldspathic dental porcelain group (Group 1), the polished zirconia group (Group 2), and the polished zirconia
with glazing group (Group 3). Twenty specimens were prepared from each
group. Each procedure such as plasticity, condensation, and glazing was
conducted according to the manufacturer's manual. A wear test was conducted with 240,000 chewing cycles using a dual-axis chewing simulator. The degree of wear
of the antagonistic teeth was calculated by measuring the volume loss
using a three-dimensional profiling system and ANSUR 3D software. The
statistical significance of the measured degree of wear was tested with a significant level of 5% using one-way ANOVA and the Tukey test.
The degrees of wear
of the antagonistic teeth were 0.119 ± 0.059 mm(3) in Group 1, 0.078 ±
0.063 mm(3) in Group 3, and 0.031 ± 0.033 mm(3) in Group 2. Statistical
significance was found between Group 1 and Groups 2 and between Group 2
and 3, whereas no statistical significance was found between Group 1 and
Despite the limitations of this study on the evaluation of antagonistic teeth wear, the degree of antagonistic tooth wear was less in zirconia than feldspathic dental porcelain, representing that the zirconia may be more beneficial in terms of antagonistic tooth wear.