Fracture strength of the IPS empress crown: The effect of occlusal using depth and axial inclination on lower first molar.
- Author:
Sung Hoon KIM
1
;
Jin Han LEE
;
Yu Lee KIM
;
Jin Keun DONG
Author Information
1. Department of Prosthodontics, College of Dentistry, Wonkwang University, Korea. Dong@wonkwang.ac.kr
- Publication Type:Original Article
- Keywords:
Axial inclination;
Fracture strength;
IPS Empress Crown;
Occlusal depth
- MeSH:
Ceramics;
Crowns*;
Molar*;
Resin Cements
- From:The Journal of Korean Academy of Prosthodontics
2003;41(1):48-60
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
The purpose of this study was to compare the fracture strength of the IPS Empress ceramic crown according to the occlusal depth (1.5mm, 2.0mm, 2.5mm) and axial inclination (4degree, 8degree, 12degree) of the lower First Molar. After 10 metal dies were made for each group, the IPS Empress ceramic crowns were fabricated and cemented with resin cement(Bistite resin cement, Tokuyama Soda Co. LTD., Japan). The cemented crowns were mounted on the testing jig with inclination of 30 degrees and the universal testing machine(Zwick Z020, Zwick, Germany)was used to measure the fracture strength. The results of this study were as follows : 1. The fracture strength of the ceramic crown with 2.5mm depth and 12degree inclination was the highest (1789 N). Crowns of 1.5 mm depth and 4degree inclination had the lowest strength (1091 N). 2. There were no significant differences in the fracture strength by axial inclination of the same occlusal depth group. 3. Most fracture lines began at the loading area and extended through proximal surface perpendicular to the margin, irrespective of occlusal depth. Size of fragment was affected by the amount of occlusal reduction.
