title: Effect of ferrule location on the fracture resistance of crowned mandibular premolars: An in vitro study.
abstract: BACKGROUND
  How the location of a ferrule affects the fracture resistance of endodontically treated mandibular premolars is unclear.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to compare the effect of ferrule location on the fracture resistance of endodontically treated mandibular premolars.
  
  
  METHODS
  Seventy-two extracted human mandibular premolars were selected and divided into 6 test groups (n = 12) according to ferrule location: control group, GHT; endodontically treated teeth without endodontic posts and crowns, GCF; teeth with a 2 mm circumferential ferrule, GBF; teeth with a 2 mm buccal ferrule; GLF, teeth with a 2 mm lingual ferrule; GBLF, teeth with a 2 mm buccal and lingual ferrule; and teeth without ferrule, GWF. After glass fiber posts were cemented with a self-adhesive resin cement and foundation restorations were placed, NiCr crowns were luted to each prepared tooth. All specimens were quasistatically loaded at 30 degrees in a universal testing machine until fractured. Data were then analyzed with 1-way ANOVA, followed by multiple comparisons using the Tukey honestly significant difference test (α=.05).
  
  
  RESULTS
  Mean ± SD failure loads for groups ranged from 791.1 ± 177.5 N to 1086.1 ± 181.1 N. One-way ANOVA revealed a statistically signiﬁcant difference between the groups (P ≤ .05). However, no statistically significant differences were observed among groups (P > .05), except between GHT (control group) and groups GBLF and GWF (P = .025, P = .022).
  
  
  CONCLUSIONS
  Within the limitations of this study, the location of the ferrule had no significant effect on the fracture resistance of endodontically treated mandibular premolars.
authors: Visiting Assistant Professor, Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University at Kiel, Germany; and Department of Fixed Prosthodontics, Faculty of Dentistry, University of Aleppo, Aleppo, Syria. Department of Fixed Prosthodontics, School of Dentistry, Ibb University, Yemen. Electronic address: asamran@proth.uni-kiel.de.
authors: Abdulaziz
authors: A
authors: Samran
authors: Lecturer, Department of Fixed Prosthodontics, Faculty of Dentistry, University of Aleppo, Syria; and Department of Restorative Dental Sciences, Al-Farabi Dental College, Riyadh, Saudi Arabia.
authors: Mahmoud
authors: M
authors: Al-Afandi
authors: Assistant Professor, Department of Fixed Prosthodontics, School of Dentistry, Aleppo University, Syria.
authors: Jad-Alkareem
authors: JA
authors: Kadour
authors: Professor and Chairman, Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University at Kiel, Germany.
authors: Matthias
authors: M
authors: Kern
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D001641:Bicuspid / Q000503:physiopathology*; D002484:Cementation / Q000379:methods; D002858:Chromium Alloys / Q000737:chemistry; D003442:Crowns; D045662:Dental Etching / Q000379:methods; D003764:Dental Materials / Q000737:chemistry; D017267:Dental Prosthesis Design; D003799:Dental Stress Analysis / Q000295:instrumentation; D005898:Glass / Q000737:chemistry; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D008334:Mandible; D011176:Post and Core Technique / Q000295:instrumentation*; D019279:Resin Cements / Q000737:chemistry; D018915:Root Canal Preparation / Q000379:methods; D013314:Stress, Mechanical; D013499:Surface Properties; D014082:Tooth Fractures / Q000503:physiopathology*; D019231:Tooth Preparation, Prosthodontic / Q000295:instrumentation*; D014092:Tooth Root / Q000293:injuries; D019553:Tooth, Nonvital / Q000503:physiopathology*
chemical_list: D002858:Chromium Alloys; D003764:Dental Materials; D005899:Glass Ionomer Cements; D019279:Resin Cements; C009753:fiberglass; D000537:Aluminum Oxide