|
KMID : 0362420110490020161
|
|
Journal of Korean Academy of Prosthodontics
2011 Volume.49 No. 2 p.161 ~ p.167
|
|
|
Influence of porcelain re-firing on the formation of surface bubble and on the change in shade of metal-ceramic crown exposed to artificial saliva
|
|
Park Ji-Hyun
Yeo In-Sung
Kim Sung-Hun
Han Jung-Suk
Lee Jai-Bong
Yang Jae-Ho
|
|
|
Abstract
|
|
|
PURPOSE: The purpose of this study was to evaluate the influence of porcelain re-firing on the formation of surface bubble and on the change in shade of metal-ceramic crown exposed to artificial saliva.
MATERIALS AND METHODS: Thirty disk-shaped specimens were made in 10 mm diameter with 0.5 mm metal core thickness and 1 mm ceramic thickness. A spectroradiometer was used to determine the CIE Lab coordinates. The number and size of surface bubble were observed with a stereomicroscope. After the exposure to artificial saliva for 7 days, re-firing was performed at glazing temperature. After re-firing, the CIE Lab were calculated, and the number and size of surface bubble were observed again. The change in shade was expressed with △E . Statistical analysis was done with paired t-test for the change in the number of surface bubble and student t-test for the change in the size of surface bubble (α= 0.05).
RESULTS: Shade difference was calculated 2.14 △E units. The mean number of surface bubble was 1.33 ± 1.49 before re-firing, 3.27 ± 2.90 after re-firing. After re-firing, the number of surface bubble was significantly increased (P<.05). The mean size of surface bubble was 81.97 ± 32.03 ㎛ before re-firing, 142.94 ± 47.40 ㎛ after re-firing. After re-firing, the size of surface bubble was significantly increased (P<.05).
CONCLUSION: Shade change after re-firing was perceptible (△E < 2.0) and clinically acceptable (△E < 3.7). The number and size of surface bubble was significantly increased after re-firing. Further investigation to decrease the surface bubble on the extra oral repair of metal-ceramic crown, will be needed in future study.
|
|
|
KEYWORD
|
|
|
Metal ceramic crown, Re-firing, Shade, Surface bubble
|
|
|
FullTexts / Linksout information
|
|
|
|
|
Listed journal information
|
|
 
|