The effect of different restoration techniques on fracture strength of teeth with flared roots

The aim of this study was to investigate the effect of different restoration techniques on the fracture strength of roots with flared canals. The crowns of 50 extracted single-rooted human teeth were removed and the canals were flared. Five groups were created (n = 10): Group 1: ReforPost (Angelus) was luted using Clearfil SA Cement (Kuraray); Group 2: ReforPost and two accessory posts (Reforpin, Angelus) were luted with Clearfil SA Cement; Group 3: Restored with i-TFC post-core system (Sun Medical); Group 4: The thickness of the root-dentine was increased using composite resin (Clearfil AP-X, Kuraray) and cured with the help of Luminex. ReforPost was then luted; Group 5: Anatomic posts were created by relining ReforPost with Clearfil AP-X and then luted using Clearfil SA Cement. The cores were created with composite resin in all the samples. The crowns of sound teeth were prepared similar to a core (control, n = 10). The specimens were vertically loaded (1 mm/min), the force that was required to fracture each sample was recorded (N) and analyzed (One Way Anova, Tukey tests). No significant difference was found among the groups (p > 0.05). The roots restored by using accessory post and i-TFC post-core (Groups 2 and 3) indicated a 100% favorable fracture pattern. Ten percent of the root fractures were observed in other groups. All techniques saved the root structure and showed 80–100% favorable failure pattern. The use of i-TFC system in flared roots could be an alternative to anatomic, accessory, and prefabricated fiber posts.