title: Fracture strength of teeth restored with all-ceramic posts and cores.
abstract: OBJECTIVE
  The purpose of this in vitro investigation was to evaluate the fracture strength of endodontically treated teeth restored with different all-ceramic posts and cores.
  
  
  METHODS
  Seventy-two endodontically treated human maxillary central incisors were divided into 3 groups with 24 teeth each and restored with 1 of the following methods: prefabricated zirconia ceramic posts and resin composite buildups; zirconia ceramic posts and copy-milled alumina ceramic cores (2-piece technique), or copy-milled all-ceramic posts and cores made from a zirconia-reinforced glass-infiltrated alumina ceramic (1-piece technique). Each group was divided into 3 subgroups of 8 samples each, consisting of teeth that did not receive crown restorations and were stored for 60 days, teeth restored with all-ceramic crowns and stored for 60 days, and teeth restored with all-ceramic crowns and subjected to 1.2 million loading cycles with 30 N in a chewing simulator.
  
  
  RESULTS
  The mean fracture strengths ranged from 205 to 522 N. Prefabricated zirconia posts and resin composite buildups showed a statistically significantly lower fracture strength after chewing simulation than teeth restored with prefabricated zirconia posts and alumina ceramic cores.
  
  
  CONCLUSIONS
  All-ceramic posts and cores made with the 2-piece technique showed promising fracture strengths under the tested conditions.
authors.affiliation: Department of Prosthodontics, Propaedeutic, and Dental Materials, School of Dentistry, Christian-Albrechts University, Kiel, Germany.
authors.forename: Wiebke
authors.initials: W
authors.lastname: Friedel
authors.forename: Matthias
authors.initials: M
authors.lastname: Kern
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D020906:Air Abrasion, Dental; D000537:Aluminum Oxide / Q000737:chemistry; D001732:Bite Force; D002516:Ceramics / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry; D017267:Dental Prosthesis Design; D005898:Glass / Q000737:chemistry; D006801:Humans; D007180:Incisor / Q000503:physiopathology; D018020:Lithium Compounds / Q000737:chemistry; D008409:Mastication / Q000502:physiology; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry; D011176:Post and Core Technique / Q000295:instrumentation; D019279:Resin Cements / Q000737:chemistry; D018915:Root Canal Preparation; D013314:Stress, Mechanical; D014025:Titanium / Q000737:chemistry; D014082:Tooth Fractures / Q000503:physiopathology*; D019553:Tooth, Nonvital / Q000503:physiopathology; D015040:Zirconium / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D003188:Composite Resins; D003764:Dental Materials; C500742:ED Primer II; C118557:Empress 2; D018020:Lithium Compounds; D008689:Methacrylates; C093719:Panavia TPN-S; D010710:Phosphates; D019279:Resin Cements; D003776:Dental Porcelain; D015040:Zirconium; D014025:Titanium; D000537:Aluminum Oxide; C028541:zirconium oxide