title: Loading standardization of postendodontic restorations in vitro: impact of restorative stage, static loading, and dynamic loading.
abstract: OBJECTIVE
  The load capability of post-restored endodontically treated teeth (ETT) can be determined at different restorative stages. It was the aim of this study to compare the load capability of ETT at these stages.
  
  
  METHODS
  Maxillary central incisors were divided into 4 groups (n=10) and endodontically treated. Specimens were restored with: (I) only glass fiber posts (GFP); (II) GFP and composite build-up with 2 mm ferrule; (III and IV) with additional adhesively luted all-ceramic crowns. Group (I) to (III) were statically loaded, and group (IV) was exposed to thermomechanical loading (TML) and subsequent static loading.
  
  
  RESULTS
  The lowest median load level of 73 N was determined for group (I). The maximum median load value of 331 N was found for group (III). The comparison of Fmax [N] of group (I), (II) and (III) revealed significant differences between the groups (p<0.001). The specimens of group (IV) failed at significantly lower load values (p<0.005) as similarly restored specimens of group (III) which were only statically loaded. The stage of restoration and TML loading prior to static loading had a significant impact on fracture patterns (p=0.006).
  
  
  CONCLUSIONS
  Every additional restorative step torwards a final crown-restored ETT significantly increased the load capability. TML prior to load-to-fracture testing of the complete restorative complex, ie. post, core and crown, significantly decreased maximum load capability.
authors.affiliation: Department of Prosthodontics, Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Sterzenbach
authors.forename: M
authors.initials: M
authors.lastname: Rosentritt
authors.forename: R
authors.initials: R
authors.lastname: Frankenberger
authors.forename: S
authors.initials: S
authors.lastname: Paris
authors.forename: M
authors.initials: M
authors.lastname: Naumann
mesh_terms: D003188:Composite Resins / Q000737:chemistry; D003442:Crowns; D003764:Dental Materials / Q000737:chemistry; D003776:Dental Porcelain / Q000737:chemistry; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003793:Dental Restoration, Permanent / Q000592:standards*; D003799:Dental Stress Analysis / Q000295:instrumentation; D005898:Glass / Q000737:chemistry; D006801:Humans; D007180:Incisor / Q000473:pathology; D055115:Light-Curing of Dental Adhesives / Q000379:methods; D018020:Lithium Compounds / Q000737:chemistry; D008422:Materials Testing; D011176:Post and Core Technique / Q000295:instrumentation; D019279:Resin Cements / Q000737:chemistry; D012389:Root Canal Obturation / Q000379:methods; D018915:Root Canal Preparation / Q000379:methods; D013314:Stress, Mechanical; D013696:Temperature; D019553:Tooth, Nonvital / Q000628:therapy*
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C118557:Empress 2; D018020:Lithium Compounds; C483522:LuxaCore; C483701:Rely X Unicem; D019279:Resin Cements; C009753:fiberglass; D003776:Dental Porcelain