MTA versus CEM root-end fillings effect on fracture resistance of endodontically treated simulated immature teeth restored with cast metal posts: an in-vitro study

Abstract

Background: Endodontically treated immature teeth which are restored with cast metal posts are of the most susceptible teeth to fracture. An apical plug is usually used as root end filling in order to seal the wide apical foramen. The current study was performed to evaluate the effect of different root-end filling materials (MTA and CEM) on fracture resistance of teeth restored with cast metal posts.Methods: A total of 40 extracted intact single-rooted human mandibular premolars (removed for orthodontic reasons) were used in the study. The coronal part of each tooth was removed and root canal preparation was performed. A size 4 Gates Glidden drill was used to enlarge the canal and was passed through the apical foramen in order to simulate an immature apex. Samples were randomly divided into 5 groups according to apical plug (Group 1: No plug, Group 2: 5 mm MTA plug, Group 3: 5 mm CEM plug, Group 4: 2 mm MTA plug, Group 5: 2 mm CEM plug). Post-space preparations were performed and cast metal post-and-cores were fabricated and cemented. Fracture resistance was assessed using a universal testing machine. Fracture thresholds were recorded and data were analyzed using SPSS 16.0 with significance level at P value < 0.05. Results The analysis showed a significant difference of fracture resistance between groups (p-value<0.05). The mean fracture resistance of samples in group 1 was significantly lower than group 2 (p-value=0.003). there was no significant difference between other groups (p-value>0.05).Conclusions: Within the limits of this study, the evidence indicated that placement of a 5 mm MTA apical plug increased the fracture resistance in simulated immature teeth which are restored with cast metal posts, compared to control group (gutta-percha and sealer). While the results were not as promising for a 2 mm MTA apical plug or either 2 or 5 mm CEM apical plug.