Bioactivity and sealing ability of polypropyleneglicole-modified MTA as innovative sealer

Objectives: Calcium-silicate cements based on MTA (Mineral Trioxide Aggregate) demonstrated excellent biocompatibility and a wide range of clinical applications. The hypothesis of the study was that MTA cements modified by PPG for root canal sealer have sealing ability and bioactivity properties. Methods: an experimental root canal sealer (PPG-MTA) was obtained adding barium sulphate, sodium fluoride and calcium sulphate to a tricalcium-silicate/dicalcium-silicate powder was mixed with polypropylene-glicole (PPG). Extracted single-rooted human teeth were instrumented with ProTaper NiTi rotary instruments, filled with single-cone gutta-percha technique in association with the experimental sealer or with CRCS sealer (Hygienic, USA) as control and stored in phosphate-containing solution (DPBS) 37°C. The sealing of each root was assessed at 24 hours, 1 week and 1 month by a fluid filtration device working at 1 psi pressure. Surface morphology and bioactivity of cement disks stored for 24 hours, 1 week and 1 month in DPBS were evaluated by ESEM/EDX, RAMAN and FTIR. Results: statistically lower filtration rate (i.e. better sealing ability) was demonstrated by PPG-MTA at 24 hours and 1 week examinations. ESEM showed the dense structure of experimental cement and EDX revealed high amounts of calcium and silicon on 24-hours aged samples, and Ca and P on 1-week and 1-month aged samples. Diffuse deposits of apatite spherulites were detected on aged samples of experimental cement. RAMAN and FTIR showed apatite bands on 24-hours and 1 week aged samples. CRCS did not showed any apatite bands. Conclusions: the ability of the experimental cement PPG–MTA to produce apatite as index of bioactivity was demonstrated. The study support the use of PPG–MTA as sealers in association with gutta-percha for root canal therapy.