title: The reinforcement effect of polyethylene fibre and composite impregnated glass fibre on fracture resistance of endodontically treated teeth: An in vitro study.
abstract: OBJECTIVE
  The aim of this study was to evaluate the fracture resistance of endodontically treated maxillary premolars with wide mesio-occluso-distal (MOD) cavities restored with either composite resin, or composite resin reinforced with different types of fibres.
  
  
  METHODS
  Fifty human maxillary premolars were selected. Five intact teeth served as positive controls. Endodontic therapy was carried out in the remaining forty-five teeth. Standardized MOD cavities were prepared in all the teeth. The teeth were restored with a nanocomposite using an incremental technique. These forty five teeth were randomly divided into three experimental groups (Group A, B and C) (n = 15). The teeth in Group A did not undergo any further procedures. The teeth in Group B and C were reinforced with composite impregnated glass fibre and polyethylene fibre, respectively. Fracture resistance was measured in Newtons (N).
  
  
  RESULTS
  The positive controls showed the highest mean fracture resistance (811.90 N), followed by Group B (600.49N), Group A (516.96N) and Group C (514.64N), respectively. One Way analysis of variance (ANOVA) test revealed a statistically significant difference between all the groups (P = 0.001). Post-hoc Tukey test revealed a moderately significant difference (P = 0.034) between Control and Group B, and a strongly significant difference between Control and Group A (P = 0.002), and Control and Group C (P = 0.001).
  
  
  CONCLUSIONS
  Endodontic therapy and MOD cavity preparation significantly reduced the fracture resistance of endodontically treated maxillary premolars (P = 0.001). No statistically significant difference was found between the experimental groups (Group A, B and C) (P > 0.1). However, the fracture resistance of the composite impregnated glass fibre reinforced group was much higher than the others.
authors.affiliation: Department of Conservative Dentistry and Endodontics, The Oxford Dental College, Hospital and Research Centre, Bommanhalli, Hosur Road, Bangalore, Karnataka, India.
authors.forename: Archana
authors.initials: A
authors.lastname: Luthria
authors.forename: A
authors.initials: A
authors.lastname: Srirekha
authors.forename: Jayshree
authors.initials: J
authors.lastname: Hegde
authors.forename: Rupali
authors.initials: R
authors.lastname: Karale
authors.forename: Sanjana
authors.initials: S
authors.lastname: Tyagi
authors.forename: Sajeev
authors.initials: S
authors.lastname: Bhaskaran
keywords: Composite impregnated glass fibre; fracture resistance; mesio-occluso-distal cavity; polyethylene fibre