title: [Fracture strength of custom-fabricated celay all-ceramic post and core].
abstract: OBJECTIVE
  The purpose of this study is to compare the fracture strengths of custom-fabricated Celay all-ceramic post-core, custom cast metal post-core, and prefabricated stainless steel post (Parapost) plus composite resin core with or without a 2.0 mm dentine ferrule.
  
  
  METHODS
  A total of 60 recently extracted human maxillary central incisors were endodontically treated and divided into five groups of 12. They were given the following treatments: Group A: Celay ceramic post-core with 2.0 mm dentine ferrule, Group B: Celay ceramic post-core with no dentine ferrule, Group C: cast metal post-core with 2.0 mm dentine ferrule, Group D: cast metal post-core with no dentine ferrule, and Group E: prefabricated post and composite core with 2.0 mm dentine ferrule. All specimens were stored at 100% humidity at room temperature for 30 days before testing. Each specimen was in a special jig at a 45 degrees angle to the long axis and subjected to a load on MTS 810 universal material testing machine until failure, with crosshead speed of 0.02 cm/min. Analysis of variance followed by the Newman-Keuls pairwise multiple comparison test was used to compare the results of the groups tested.
  
  
  RESULTS
  There was a statistically significant difference between five groups (P < 0.01). Celay ceramic post-core with 2.0 mm dentine ferrule (758.35 N +/- 119.26 N) and cast metal post-core with 2.0 mm dentine ferrule (756.63 N +/- 166.22 N) had a significantly larger mean failure threshold for fracture than the other three groups which had no significant difference between each other. There was a statistically significant difference between the fracture resistance of Celay post-core restored teeth with and without 2.0 mm dentine ferrule.
  
  
  CONCLUSIONS
  The custom-fabricated Celay post-core could be a choice for clinical use in endodontically treated tooth when the final restoration is an all-ceramic crown and the preparation has a 2.0 mm dentine ferrule.
authors.affiliation: Department of Dentistry, Beijing Hospital.
authors.forename: Yuxing
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zhiyue
authors.initials: Z
authors.lastname: Lu
authors.forename: Keli
authors.initials: K
authors.lastname: Wang
mesh_terms: D002516:Ceramics; D003442:Crowns; D003776:Dental Porcelain / Q000737:chemistry*; D019232:Dental Restoration Failure; D006801:Humans; D007180:Incisor; D007284:Inlays; D008422:Materials Testing; D011176:Post and Core Technique; D013314:Stress, Mechanical; D014082:Tooth Fractures / Q000517:prevention & control
chemical_list: C078572:Celay; D003776:Dental Porcelain