title: Fracture resistance of compromised endodontically treated teeth restored with bonded post and cores: An in vitro study.
abstract: BACKGROUND
  It is unclear which post and core system performs best when bonded to severely compromised endodontically treated teeth.
  
  
  OBJECTIVE
  The purpose of this study was to investigate the fracture resistance and mode of failure of severely compromised teeth restored with 3 different adhesively bonded post and core systems.
  
  
  METHODS
  Thirty extracted endodontically treated maxillary anterior teeth were randomly divided into 3 groups, CPC, gold cast post and core; TPC, titanium prefabricated post/composite resin core; and FPC, quartz fiber reinforced post/composite resin core. All posts were adhesively cemented. All cores resembled a central incisor preparation with no remaining tooth structure above the finish line. Cast gold crowns were fabricated and cemented adhesively. The specimens were aged with thermocycling and cyclic loading. Two specimens per group were randomly selected for micro-computed tomographic imaging before and after aging. Failure was induced with a universal testing machine. The mode of failure was characterized by the interface separation. Data were analyzed with 1-way ANOVA (α=.05) followed by post hoc tests (Bonferroni).
  
  
  RESULTS
  A statistically significant difference was found among the 3 groups (P=.002). CPC was significantly different than TPC (P=.008) or FPC (P=.003). The primary mode of failure for CPC and TPC was root fracture, and for FPC post debonding.
  
  
  CONCLUSIONS
  Severely compromised endodontically treated teeth restored with bonded gold cast post and cores showed significantly higher fracture resistance.
authors.affiliation: Assistant Professor, Department of General Dental Sciences, Marquette University School of Dentistry, Milwaukee, Wis. Electronic address: gmaroulakos@yahoo.gr.
authors.forename: Georgios
authors.initials: G
authors.lastname: Maroulakos
authors.affiliation: Professor and Director, Graduate Prosthodontics, Department of Restorative Sciences, Texas A&M University, Baylor College of Dentistry, Dallas, Texas.
authors.forename: William W
authors.initials: WW
authors.lastname: Nagy
authors.affiliation: Associate Professor, Department of Restorative Sciences, Texas A&M University, Baylor College of Dentistry, Dallas, Texas.
authors.forename: Elias D
authors.initials: ED
authors.lastname: Kontogiorgos
mesh_terms: D003188:Composite Resins / Q000737:chemistry; D003442:Crowns; D003738:Dental Cements; D003764:Dental Materials; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D005898:Glass / Q000737:chemistry; D006047:Gold Alloys / Q000737:chemistry*; D006801:Humans; D007180:Incisor; D011176:Post and Core Technique; D019279:Resin Cements / Q000737:chemistry; D014082:Tooth Fractures / Q000503:physiopathology / Q000628:therapy*; D014092:Tooth Root / Q000503:physiopathology*; D019553:Tooth, Nonvital / Q000503:physiopathology / Q000628:therapy*
chemical_list: D003188:Composite Resins; D003738:Dental Cements; D003764:Dental Materials; D006047:Gold Alloys; D019279:Resin Cements