Sealing Ability of an MTA-Based-Sealer After Post Space Preparation

Method: Forty-six mandibular premolars roots were subjected to biomechanical preparation (n = 10). Roots were sterilized and the subsequent steps were performed on a laminar flow cabinet. The specimens were obturated by lateral condensation technique with an MTA-based sealer (MTA Fillapex, Angelus) or an epoxy resin-sealer (AH Plus, Dentsply). The removal of the filling material was made immediately after the obturation, leaving two different lengths of remaining filling at the apical third of the root (4mm and 8mm). The six remaining teeth were the positive and negative controls. Eppendorf tubes had their bottom portions cut to produce sample holders. The specimens were inserted into the holders in a way that the apical thirds of the roots could pass the bottom aperture of the eppendorfs, with roots apices in contact to sterile BHI. After assembling the roots into the holders, the interfaces apical third/holder were sealed with epoxy resin. An inoculum of 1x10⁷ CFU/ml was inserted on the top of the holders. Every 48h, the inoculum received sterile BHI, with daily observation for 60 days.

Result: In general, the bacterial leakage occurred 35 days after the inoculation. Some samples did not infiltrate even after 60 days. No infiltration occurred in 40% (AH Plus) and 50% (MTA Fillapex) of the roots with 8mm of remaining obturation. For both lengths of post space preparation roots filled with AH Plus showed 10% more infiltration than roots filled with MTA Fillapex.

Conclusion: The bacterial leakage after post space preparation depends on the type of cement and length of preparation.