بررسی مقایسهای مقاومت به شکست در دندانهای درمان ریشه شده با دو نوع پست و کور

Introduction: most endodontically treated teeth need post and core restoration to do acceptablepercentage of their function but selection of proper post and core system can be difficult andambiguous .this study compared the effect of cast post and core and fiberglass post and core systemon the fracture resistance and fracture pattern of crowned endodontically treated teeth. Material and method: A total of 30 recently extracted human canines with their crown removedwere endodontically treated. Two groups of 15 specimens were formed. Teeth were restored withcast post core in the 1st group and with fiberglass post in the 2ndgroup. All posts were cementedwith panavia F2 adhesive system. All fiber posts were restored with composite core. Cemented with zinc phosphate cement. Each specimen embedded in acrylic resin and then scored in universal load-testing machine (Instron). A compressive load was applied at a 45 angle to the long axis of thetooth until fracture at a crosshead speed of 1mm/min. Result: the Fracture resistance of 2 groups according to the (t) test analysis didn't have anysignificant difference. The mean fracture resistance of the teeth restored with cast - post systemwere 1489.33 ± 1045.34 and facture resistance of the teeth restored with fiber glass were 1195.93± 624.12.teeth restored with cast post exhibited higher fracture resistance than the other group.Fracture that occur in teeth restored with fiberglass post and composite core usually arerestorable and %80 of fracture that occur in teeth restored with cast post and core are notrestorable. Discussion: considering that fracture resistance of teeth in tow groups evaluated in this studywere not significantly different and fracture of tooth restored with Fiber glass post were from apoint that was more easily restorable , compare to cast post and core if seems reasonable to useFiber glass post in appropriate cases. Although it is suggested to do and evaluate other clinicalstudy's in long term. Key word: Post and Core technique, Fiber glass post, fracture resistance