Fracture strengths of endocrown restorations fabricated with different preparation depths and CAD/CAM materials

• Published in: Dental Materials Journal Vol. 37; no. 2; pp. 256 - 265
• Main Authors: Burcu KANAT-ERTURK, Serkan SARIDAG, Ege KOSELER, Dilek HELVACIOGLU-YIGIT, Egemen AVCU, Yasemin YILDIRAN-AVCU
• Format: Journal Article
• Language: Japanese
• Published: Japanese Society for Dental Materials and Devices 01.04.2018
• ISSN: 0287-4547

The objectives of this study were to compare the fracture strength of endocrown restorations fabricated with different preparation depth and various CAD/CAM ceramics, and to assess the fracture types. Endodontically treated 100 extracted human permanent maxillary centrals were divided into two preparation depth groups as short (S : 3-mm-deep) and long (L : 6-mm-deep) , then five ceramic subgroups, namely : feldspathic-ceramic (Vita Mark II-VM2) , lithium-disilicate glass-ceramic (IPS e.max CAD-E.max) , resin-ceramic (LAVA Ultimate-LU) , polymer infiltrated ceramic (Vita Enamic-VE) and monoblock zirconia (inCoris TZI-TZI) (n=10/subgroup) . The endocrowns were fabricated by CAD/CAM and were cemented with resin cement (RelyX U200) . The teeth were thermally cycled (5,000cycles) and fracture tests were performed at 45° angle to the teeth. The data were statistically analyzed (Kruskal-Wallis, Mann Whitney U) , failure modes were evaluated with stereomicroscopy. Zirconia group provided the statistically highest fracture strength, but also exhibited non-repairable failures. Preparation depth has an effect on the fracture strength only for feldspathic ceramic.