Lack of bioactivity of commercial endodontic sealers.

Objectives: bone like apatite formation on the surface of artificial materials is an essential requirement for materials to apply to living tissues such as apical bone. All endodontic sealers may be place in contact with apical bone tissue. The in vitro bioactivity and biological behaviour of commercial endodontic sealers for root canal therapy was investigated in real-time on wet fresh and set cements by using ESEM/EDX and Raman. Methods: AH Plus (DentSply, USA), CRCS (Hygienic, USA), Pulp Canal Sealer (Kerr, USA), ProRootMTA (DentSply, USA) and TechBiosealer endo (Isasan, Italy) a calcium-silicate cement were tested. Cement discs were prepared according with manufacturer directions and analyzed in wet conditions by ESEM/EDX (Zeiss EVO 50, Carl Zeiss, Germany) and micro-Raman (i) immediately after their preparation, (ii) after 24 hrs of immersion in DPBS used as simulated body fluids solution (SBF) and (iii) after 28 days at 37°C. Setting time, pH and calcium releasing were tested. Results: ESEM/EDX on fresh wet samples displayed the elements of material composition and an homogeneous flat surface with many voids. After 24 hrs and 28 days, only ProRoot MTA and calcium-silicate cements resulted covered by small spherulites deposits which resulted mainly composed by Calcium and Phosphorus. Micro-Raman demonstrated the appearance of apatite bands after 24 hours and after 28 days only on these cements. On the contrary, the other sealers did not displayed any surface deposits at any time. MicroRaman at 24 hrs and 28 days did not showed apatite bands. Conclusions: all commercial endodontic sealers resulted unable to induce formation of bone-like apatite layer and suggest a lack of bioactivity. On the contrary, ProRootMTA and TechBiosealer endo demonstrated earlier bioactivity.