MTA Cements Mixed with Hydrophilic Polymer Are Bioactive Endodontic Sealers

Objectives: calcium-silicate cement based on MTA (Mineral Trioxide Aggregate) demonstrated excellent biocompatibility and the ability to set in moist conditions. The hypothesis of the study was that endodontic sealers derived from calcium-silicate MTA cements possess sealing ability and bioactivity properties. Methods: an experimental root canal sealer (TC-PPG) was obtained adding barium sulphate to a tricalcium-silicate/dicalcium silicate hydraulic powder that was mixed with an hydrophilic polymer PPG (polypropilene-glicol). Extracted single-rooted human teeth were instrumented with ProTaper rotary instruments, irrigated with NaOCl and EDTA and filled with single-cone gutta-percha technique in association with the experimental sealer or with CRCS sealer (Hygienic, USA) as control and stored in simulated body fluid DPBS (Dulbecco's Phosphate Buffered Saline) solution at 37°C. The sealing of each root was assessed at 24 hours and 1 and 3 weeks by a digital fluid flow-meter (University of Bologna, Italy). Sealer morphology and bioactivity were evaluated by ESEM/EDX analyses on materials stored for 6 and 24 hours, 1 and 4 weeks in DPBS. Results:statistically significant differences (p<0.05) were found among the sealers at all analysis times. Statistically lower filtration rate was demonstrated by TC-PPG. ESEM showed a dense structure of the experimental cement and EDX revealed high amounts of calcium and silicon on 24 hours-stored samples, while revealed Ca and P on 1 week and 1 month-aged samples. Diffuse deposits of apatite spherulites were detected on 1 and 4 weeks-stored samples only on the experimental cement, whilst CRCS did not showed neither apatite spherulites deposits nor Ca, P peaks. Conclusions: the study confirmed the optimal sealing ability and the bioactivity of calcium-silicate cement and support the proposal of using PPG modified calcium-silicate cement as sealers in association with single-cone gutta-percha for root canal filling. The ability to form apatite may explain the improving sealing demonstrated by materials during the time.