ObjectiveConsidering that periodontal ligament simulation may influence the stress
distribution over teeth restored with intraradicular retainers, this study aimed
to assess the combined effect of mechanical cycling and periodontal ligament
simulation on both the bond strength between fiber posts and root dentin and the
fracture resistance of teeth restored using glass fiber posts.Material and MethodsNinety roots were randomly distributed into 3 groups (n=10) (C-MC: control; P-MC:
polyether; AS-MC: addition silicone) to test bond strength and 6 groups (n=10) (C:
control; P: polyether; AS: addition silicone, without mechanical cycling, and
C-MC, P-MC and AS-MC with mechanical cycling) to test fracture strength, according
to the material used to simulate the periodontal ligament. For the bond strength
test, fiber posts were cemented, cores were built, mechanical cycling was applied
(2×106 cycles, 88 N, 2.2 Hz, and 45º incline), and the teeth cut into 3 slices (2
mm), which were then subjected to the push-out test at 1 mm/min. For the fracture
strength test, fiber posts were cemented, cores were built, and half of the groups
received mechanical cycling, followed by the compressive strength (45° to the long
axis and 1 mm/min) performed on all groups.ResultsPeriodontal ligament simulation did not affect the bond strength (p=0.244) between
post and dentin. Simulation of periodontal ligament (p=0.153) and application of
mechanical cycling (p=0.97) did not affect fracture resistance.ConclusionsThe materials used to simulate the periodontal ligament did not affect fracture or
bond strength, therefore periodontal ligament simulation using the tested
materials could be considered optional in the conditions of the study.