title: The effect of fiber post presence and restorative technique on the biomechanical behavior of endodontically treated maxillary incisors: an in vitro study.
abstract: BACKGROUND
  Unresolved controversy exists concerning the best technique for restoring endodontically treated teeth. Prefabricated posts have been recommended with some debate as a method of restoring pulpless teeth before placement of the final restoration.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to evaluate the effect on the strain, fracture resistance, and fracture mode of endodontically treated human incisors of 4 types of restorations with or without glass fiber posts after thermal cycling.
  
  
  METHODS
  Ninety human maxillary central incisors were selected and divided into 1 control group and 8 treatment groups (n=10). The teeth were endodontically treated and received 2 large Class III preparations simulating coronal destruction. The teeth were then restored with or without glass fiber posts and by using 4 restorative techniques: direct composite resin, direct composite veneer, feldspathic ceramic veneer, or a feldspathic ceramic crown. After artificial aging by thermal cycling, the incisors were loaded at a 135-degree angle, and the strain was measured by using strain gauges placed on the facial and proximal root surfaces. Specimens were subsequently loaded to the point of fracture. Strain and fracture resistance results were analyzed by a 1-way and 2-way ANOVA, followed by the Tukey HSD and Dunnett tests (α=.05).
  
  
  RESULTS
  One-way analyses showed that the control group and the direct composite resin restoration with and without post groups presented significantly higher fracture resistance values (P<.001). Two-way analyses showed no significant differences for the post system. Proximal strain values were higher in the control and composite resin groups and lower in the feldspathic ceramic groups.
  
  
  CONCLUSIONS
  The presence of glass fiber posts did not increase the fracture resistance of endodontically treated incisors. Conservative composite resin restorations showed higher fracture resistance values.
authors.affiliation: Biomechanics Group, Department of Operative Dentistry and Dental Materials, MG, Brazil.
authors.forename: Andréa Dolores Correia Miranda
authors.initials: AD
authors.lastname: Valdivia
authors.forename: Luís Henrique Araújo
authors.initials: LH
authors.lastname: Raposo
authors.forename: Paulo Cézar
authors.initials: PC
authors.lastname: Simamoto-Júnior
authors.forename: Veridiana Rezende
authors.initials: VR
authors.lastname: Novais
authors.forename: Carlos José
authors.initials: CJ
authors.lastname: Soares
mesh_terms: D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D003188:Composite Resins; D003442:Crowns; D003776:Dental Porcelain; D019232:Dental Restoration Failure; D003793:Dental Restoration, Permanent / Q000379:methods*; D003799:Dental Stress Analysis; D003801:Dental Veneers; D005898:Glass; D006801:Humans; D007180:Incisor / Q000502:physiology; D008437:Maxilla; D011176:Post and Core Technique; D018709:Statistics, Nonparametric; D019553:Tooth, Nonvital
chemical_list: D003188:Composite Resins; C009753:fiberglass; D003776:Dental Porcelain