TY  - JOUR
T1  - Effect of Zirconia Coping Design on Fracture Resistance of
Veneering Porcelain in All-Ceramic Posterior Crowns
AU - Ramezani, Mojtaba AU - Alhavaz, Abdol Hamid AU - Bagheri, Mohammad Ali AU - Ahmadi, Sadegh Pour AU - Bijani, Ali 
JO  - Journal of Engineering and Applied Sciences
VL  - 12
IS  - 6
SP  - 1623
EP  - 1628
PY  - 2017
DA  - 2001/08/19
SN  - 1816-949x
DO  - jeasci.2017.1623.1628
UR  - https://makhillpublications.co/view-article.php?doi=jeasci.2017.1623.1628
KW  - Fracture
KW  -zirconia core
KW  -all-ceramic restoration
KW  -core designs
KW  -conventional
AB  - When the zirconia core is fabricated in a uniform thickness and veneering porcelain has variable thicknesses, it maybe undergoes chipping. This study aimed to compare the fracture load of restorations fabricated with two different zirconia core designs. The 24 metal dies were divided into 2 groups for fabrication of zirconia cores: conventionally (0.5 mm thickness); customized design. After the porcelain was applied, the crowns were cemented. Using a universal testing machine a compressive vertical load was applieduntil failure. Data were analyzed with SPSS17, using t-test, <i>X</i><sup>2</sup>-test and Mann-Whitney U test. The mean fracture loads were 2254.1773&plusmn;404.4 and 2885.4327&plusmn;670.5 N for conventional and customized zirconia core designs, respectively. Student&#146;s t-test revealed that the fracture load of the customized group was significantly higher than that of the conventional group (p&lt;0.001). Crowns with customized design have higher fracture resistance than those with conventional design.
ER  -