The aim of this study was to evaluate the biomechanical behavior and long-term safety of high performance polymer PEKK as an intraradicular dental post-core material through comparative finite element analysis (FEA) with other conventional post-core materials. A 3D FEA model of a maxillary central incisor was constructed. A cyclic loading force of 50 N was applied at an angle of 45° to the longitudinal axis of the tooth at the palatal surface of the crown. For comparison with traditionally used post-core materials, three materials (gold, fiberglass, and PEKK) were simulated to determine their post-core properties. PEKK, with a lower elastic modulus than root dentin, showed comparably high failure resistance and a more favorable stress distribution than conventional post-core material. However, the PEKK post-core system showed a higher probability of debonding and crown failure under long-term cyclic loading than the metal or fiberglass post-core systems.

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Background/purpose Bacterial infection is closely associated with the failure of endodontic treatment, and use of endodontic sealer with antimicrobial activity and biological compatibility is necessary for the success of root canal treatment. The purpose of this study was to investigate and to compare the antibacterial effect of two calcium silicate-based root canal sealers (Endoseal and EndoSequence BC sealer) as recent development sealers and with three conventional root canal sealers (AH Plus, Sealapex, and Tubli-Seal), before or after setting, on Porphyromonas endodontalis, Porphyromonas gingivalis , and Enterococcus faecalis. Materials and methods The sealers were soaked in phosphate buffered saline to elute its compositions after and before setting, and the elutes were performed the antimicrobial assay. Also, X-ray fluorescence analysis was carried out to compare compositions of two calcium silicate-based sealers. Results The conventional root canal sealers have strong antibacterial activity against the Gram-negative bacteria, P. endodontalis and P. gingivalis . Endoseal sealer showed antibacterial activity against not only the Gram-negative bacteria, but also against the Gram-positive bacteria, E. faecalis . However, Endosequence BC sealer exhibited a weak antibacterial effect on all bacteria in this study. X-ray fluorescence analysis exhibited that Endoseal contained more types and more amount of the oxide compound known to have strong antimicrobial activity such as Al 2 O 3 , Fe 2 O 3 , MgO, Na 2 O, NiO, and SO 2 than Endoseqeunce BC. Conclusion Endoseal, which contains various types of oxide compounds, seems to be a suitable sealer for preventing bacterial infection in both treated and untreated root canals.

The objective of this study was to assess the cytotoxicity of EndoSeal, a novel mineral trioxide aggregate-based root canal sealer in comparison with two commonly used sealers, AH Plus and Sealapex. For cytotoxicity assay, MG-63 cells and human gingival fibroblasts were incubated in culture medium containing eluates of each sealer at 1, 3, and 7 days. Cell metabolism was evaluated by the WST-1 assay. For cell adhesion assay, disc specimens were fabricated from EndoSeal and AH Plus. MG-63 cells and human gingival fibroblasts were seeded on the discs, and after 1 day and 7 days of incubation, cell morphology and cell adhesion were examined by SEM. The order of cytotoxicity of root canal sealers was as follows: EndoSeal < AH Plus < Sealapex. Both types of cells seeded on the EndoSeal specimens were much larger, flat with rough margins compared to those on the AH Plus specimens. These results suggest that EndoSeal has a satisfactory cytocompatibility.