title: Fracture strength of custom-fabricated Celay all-ceramic post and core restored endodontically treated teeth.
abstract: BACKGROUND
  The increased use of all-ceramic crown provides a rationale for tooth-colored core. Due to superior mechanical properties, Vita Celay infiltration ceramic developed for crown and bridge works presents the potential for fabricating all-ceramic posts and cores in one piece. This study was conducted to compare the fracture strength of endodontically treated teeth which were thereafter given different types of posts and cores and crowns restoration, respectively. The evaluated post-and-core systems are: custom-fabricated Celay all-ceramic post-core, custom cast metal post-core, and prefabricated stainless steel post (Parapost) with and without 2.0 mm dentine ferrule.
  
  
  METHODS
  Sixty freshly extracted human maxillary central incisors were endodontically treated and randomly divided into five groups with 12 samples each. Group A: Celay ceramic post-cores restored teeth with 2.0 mm dentine ferrule. Group B: Celay ceramic post-cores restored teeth with no dentine ferrule. Group C: cast metal post-cores restored teeth with 2.0 mm dentine ferrule. Group D: cast metal post-cores restored teeth with no dentine ferrule. Group E: prefabricated post and composite cores restored teeth with 2.0 mm dentine ferrule. All teeth were restored with Celay ceramic crowns. Each specimen was subjected to a load at a 45-degree angle to the long axis on MTS 810 material testing machine until failure, at crosshead speed of 0.02 cm/minute. Analysis of variance followed by the Newman-Keuls pairwise multiple comparison tests were used to compare the results of the groups tested.
  
  
  RESULTS
  There was a statistically significant difference among the five groups (P < 0.01). Celay ceramic post-cores restored teeth with 2.0 mm dentine ferrule [(758.35+/-19.26) N] and cast metal post-cores restored teeth with 2.0 mm dentine ferrule [(756.63+/-66.22) N] had a significantly greater mean fracture strength than the other three groups in which no significant difference was observed. The 2.0 mm dentine ferrule could cause significant fracture resistance alteration of Celay post-core restored teeth.
  
  
  CONCLUSIONS
  When covered with Celay ceramic crowns, Celay post-cores restored teeth with 2.0 mm dentine ferrule and cast metal post-cores restored teeth with 2.0 mm dentine ferrule have similar fracture strength. There was a statistically significant difference between the fracture resistance of Celay post-core restored teeth with and without 2.0 mm dentine ferrule.
authors.affiliation: Department of Dentistry, Beijing Hospital, Beijing 100730, China. zhangyx1108@yahoo.com.cn
authors.forename: Yu-xing
authors.initials: YX
authors.lastname: Zhang
authors.forename: Wei-hong
authors.initials: WH
authors.lastname: Zhang
authors.forename: Zhi-yue
authors.initials: ZY
authors.lastname: Lu
authors.forename: Ke-li
authors.initials: KL
authors.lastname: Wang
mesh_terms: D002516:Ceramics; D003442:Crowns; D003776:Dental Porcelain; D006801:Humans; D007284:Inlays; D011176:Post and Core Technique; D013314:Stress, Mechanical; D014082:Tooth Fractures / Q000503:physiopathology*; D019553:Tooth, Nonvital / Q000503:physiopathology*
chemical_list: C078572:Celay; D003776:Dental Porcelain