title: Fracture strength of endodontically treated maxillary premolars supported by a horizontal glass fiber post: an in vitro study.
abstract: BACKGROUND
  The purpose of this study was to evaluate the effect of a horizontal glass fiber post on the fracture strength of endodontically treated maxillary premolars with mesioocclusaldistal (MOD) cavities.
  
  
  METHODS
  Sixty extracted intact upper premolars were collected, treated endodontically (except for the control group), and divided into 5 test groups (n = 12) depending on the restoration type: G1 (control group, untreated teeth), G2 (MOD preparation without restoration), G3 (MOD preparation with resin composite restoration), G4 (MOD preparation with resin composite restoration and a horizontal fiber post inserted between buccal and palatal walls), and G5 (MOD preparation with a horizontal fiber post only). The specimens were stored in normal saline at 37°C for 2 months. Then specimens were quasi-statically loaded in a universal testing machine until fracture occurred. Failure loads were then analyzed with one-way analysis of variance, followed by multiple comparisons by using Tukey honestly significant difference test (α = .05). The mode of failure was determined by visual inspection.
  
  
  RESULTS
  Mean (standard deviation) failure loads for groups ranged from 411.8 N (±103.9) to 994.5 N (±147.3). One-way analysis of variance showed significant differences between fracture resistances of groups (P < .001). Tukey honestly significant difference test showed significant differences in fracture resistance within groups (P ≤ .05) except between the G1 (control group) and group G4 (P ≥ .05). All groups (except G4) had almost favorable fracture mode within the cervical third of the roots.
  
  
  CONCLUSIONS
  Under the conditions of this in vitro study, a horizontal glass fiber post in a MOD cavity increased significantly the fracture resistance of the endodontically treated upper premolars.
authors.affiliation: Department of Fixed Prosthodontics, Faculty of Dentistry, Aleppo, Syria; Department of Restorative Dental Sciences, Al-Farabi Colleges, Riyadh, Saudi Arabia.
authors.forename: Wassim
authors.initials: W
authors.lastname: Karzoun
authors.affiliation: Department of Fixed Prosthodontics, Faculty of Dentistry, Aleppo, Syria.
authors.forename: Amid
authors.initials: A
authors.lastname: Abdulkarim
authors.affiliation: Department of Fixed Prosthodontics, School of Dentistry, Ibb University, Ibb, Yemen; Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University, Kiel, Germany. Electronic address: aasamran@gmail.com.
authors.forename: Abdulaziz
authors.initials: A
authors.lastname: Samran
authors.affiliation: Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University, Kiel, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Kern
mesh_terms: D001641:Bicuspid; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D005898:Glass; D006801:Humans; D011176:Post and Core Technique; D014082:Tooth Fractures / Q000517:prevention & control*; D019553:Tooth, Nonvital / Q000473:pathology* / Q000628:therapy
chemical_list: C009753:fiberglass
keywords: Endodontically treated premolars; MOD cavity; fracture resistance; glass fiber post; resin cement