title: The effect of fibre insertion on fracture resistance of root filled molar teeth with MOD preparations restored with composite.
abstract: OBJECTIVE
  To evaluate the effect of using flowable composite with or without leno woven ultra high modulus polyethylene fibre reinforcement on fracture resistance of root filled mandibular molars with mesio-occlusodistal (MOD) preparations.
  
  
  METHODS
  Sixty sound extracted human mandibular molars were randomly assigned to five groups (n = 12). Group 1 did not receive any preparation. From groups 2 to 5, the teeth were root filled and MOD preparations were created. Group 2 remained unrestored. Group 3 was restored with a dentine bonding system (DBS; SE Bond, Kuraray, Japan) and composite resin (CR) (AP-X; Kuraray). In group 4, flowable composite resin (Protect Liner F; Kuraray) was used before restoring teeth with CR. In group 5, leno woven ultra high modulus polyethylene ribbon fibre (Ribbond, Seattle, WA, USA) was inserted into the cavities in a buccal to lingual direction and the teeth were then restored with DBS and CR. After finishing and polishing, the specimens were stored in 100% humidity at 37 degrees C for 1 day. Compressive loading of the teeth was performed using a universal testing machine at a crosshead speed of 0.5 mm min(-1). The mean load necessary to fracture the samples were recorded in newtons (N) and were subjected to analysis of variance (ANOVA) and Tukey post-hoc test.
  
  
  RESULTS
  The mean load necessary to fracture the samples in each group were (in N): group 1: 1676.75 +/-154.63(a), group 2: 376.51 +/- 37.36(b), group 3: 733.23 +/- 133.33(c), group 4: 786.48 +/- 145.34(c), group 5: 943.63 +/- 121.15(d). There were statistically significant differences between the groups annotated with different letters.
  
  
  CONCLUSIONS
  (i) Use of flowable composite resin under composite restorations had no effect on fracture resistance of root filled molar teeth with MOD preparations, (ii) use of polyethylene ribbon fibre under composite restorations in root filled teeth with MOD preparations significantly increased fracture strength.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Selcuk University, Konya, Turkey. sbelli@selcuk.edu.tr
authors.forename: S
authors.initials: S
authors.lastname: Belli
authors.forename: A
authors.initials: A
authors.lastname: Erdemir
authors.forename: M
authors.initials: M
authors.lastname: Ozcopur
authors.forename: G
authors.initials: G
authors.lastname: Eskitascioglu
mesh_terms: D000704:Analysis of Variance; D003188:Composite Resins; D019245:Compressive Strength; D003736:Dental Cavity Lining / Q000379:methods*; D003737:Dental Cavity Preparation; D003793:Dental Restoration, Permanent / Q000379:methods*; D003799:Dental Stress Analysis; D017220:Dentin-Bonding Agents; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates; D008963:Molar; D011095:Polyethylenes; D011897:Random Allocation; D019279:Resin Cements; D014082:Tooth Fractures / Q000517:prevention & control*; D019553:Tooth, Nonvital
chemical_list: C112828:Clearfil AP-X; C438313:Clearfil SE Bond; D003188:Composite Resins; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D011095:Polyethylenes; C409388:Protect Liner F; C084063:RIBBOND; D019279:Resin Cements; C111840:flowable hybrid composite