Fracture susceptibility of endodontically treated teeth.

Aim: To assess the influence of cervical preparation on fracture susceptibility of roots.
Material and Methods: During root canal instrumentation, the cervical portions were prepared with different taper instruments: I: no cervical preparation; II: #30/.08; III: #30/.10; IV: #70/.12. The specimens were sealed with the following filling materials (n = 8), A: unfilled; B: Endofill/gutta-percha; C: AH Plus/gutta-percha; D: Epiphany SE/Resilon. For the fracture resistance test, a universal testing machine was used at 1 mm per minute.
Results: anova demonstrated difference (P < 0.05) between taper instruments with a higher value for group I (205.3 ± 77.5 N) followed by II (185.2 ± 70.8 N), III (164.8 ± 48.9 N), and IV (156.7 ± 41.4 N). There was no difference (P > 0.05) between filling materials A (189.1 ± 66.3 N), B (186.3 ± 61.0 N), C (159.7 ± 69.9 N), and D (176.9 ± 55.2 N).
Conclusions: Greater cervical wear using a #70/.12 file increased the root fracture susceptibility, and the tested filling materials were not able to restore resistance.
(© 2011 John Wiley & Sons A/S.)