The purpose of this study was to compare in vitro the long-term apical sealing ability of the Bio-Sealers used in association with gutta-pherca.
Materials and methods: A white Portland cement was thermally and mechanically treated and chemical compounds were added (bismuth oxide, calcium sulfate, phyllosilicate, sodium fluoride) to obtain Bio-Sealer TC and Bio-Sealer F-TC. The cement powders were mixed with articaine solution.
Extracted single-rooted human teeth were instrumented, filled with warm gutta-pherca in association with one of different Bio-Sealers or with AH Plus (control) and stored in deionized water at 37°C. The sealing of each root was detected/assessed after 24, 48 hours and 1, 2 weeks and 1,3,6 months from filling by a fluid filtration method. Additional root filled samples were sectioned to evaluate the marginal adaptation and the presence of voids by optical microscopy. Cement disks were prepared, stored in deionized water at 37°C for 24 hours and analyzed by SEM/EDX.
Results: Measurements of fluid filtration rate at 24 and 48 hours revealed no statistically significant differences between the experimental Bio-Sealers and AH Plus groups. Both Bio-Sealers showed similar or lower microleakage values (Bio-Sealer F-TC at 3 and 6 months) compared to AH Plus control group. SEM/EDX revealed high amounts of calcium imputable to the formation of calcium hydroxide (Portlandite) coating layer. Low levels of silicon, sulfur and bismuth, and traces of aluminum were detected. Optical microscopy showed little porosities in all the cement bulk.
Conclusions: This study suggests that Bio-Sealers are able to ensure a stable long-term sealing comparable with AH Plus. The results supports the proposal of using modified Portland cement as sealers in association with warm gutta-pherca for orthograde root filling therapy in clinical tests.