The Fracture Resistance Of The Endodontically Treated Molar Teeth With MOD Preparations Restored With Different Types Of Composit Material

Abstract

Compared to teeth with healthy pulps, root filled teeth are considered more susceptible to fracture. The present study was directed toward improving the effect of using flowable composite with or without polyethylene fiber reinforcement on fracture resistance of the endodontically treated mandibular molars with MOD preparations. Thirty sound extracted human mandibular molars were randomly assigned to three groups (n=10). All teeth were root filled and MOD cavity preparation were created.Group (1) was restored with a dentine bonding system(DBS: SE Bond) and composite resin( CR). In group (2), flowable composite resin ( Protect liner F) was used before restoring teeth with CR. In group (3) leno woven ultra high modulus polyethylene ribbon fiber ( Ribbond, Seattle, WA. USA) was inserted into the cavities in a buccal to lingual direction and teeth were then restored with DBS and CR. After finishing and polishing the specimens were stored in 100% humidity at 37C° for 1 day. Compressive loading of the teeth was performed using a universal testing machine at a crosshead speed of 0.5 mm min "' . the mean load necessary to fracture the samples were recorded in newtons (N) and were subjected to analysis of variance (ANOVA) and Tukey test. The results showed that the used of flowable composite resin under composite restorations had no effect on fracture resistance of root filled molars teeth with MOD preparation . while the used of polyethylene fjtffer under composite restorations in root filled teeth with MOD preparations significantly, increased fracture strength .
 Aim
 To evaluate the effect of using flowable composite with or without ultra high modulus polyethylene fiber reinforcement on fracture resistance of root filled mandibular molars with mesio - occluso-distal(MOD) preparations.