In vivo apatite-forming ability of second-generation hydraulic calcium silicate cements in rat subcutaneous tissue

Abstract Objectives The objective of this study was to evaluate the in vivo apatite-forming ability of 17 second-generation hydraulic calcium silicate cements (HCSCs) with the first-generation HCSC, white ProRoot MTA (PR). Materials and Methods Seventeen second-generation HCSCs and PR were implanted in rat subcutaneous tissue for 28 days. After inplantation, Raman spectra were taken from the surface of the HCSC implants and blindly evaluated for the presence or absence of a band at 960 cm− 1 indicating apatite. Apatite formation was also assessed with surface characterization and elemental mapping. Results The Raman band for apatite was detected on only seven second-generation HCSCs and PR. These seven HCSCs exhibited apatite-like calcium- and phosphorus-rich spherical precipitates on their surface. Three types of HCSCs had a Raman band at 962 cm− 1 that may have obscured the Raman band for apatite at 960 cm− 1; however, elemental mapping demonstrated the absence of calcium-phosphorus-rich apatite-layer-like regions on these HCSCs. Conclusions Only 7 of the 17 second-generation HCSCs and PR produced apatite in vivo within 28 days. Clinical Relevance: The 10 types of second-generation HCSCs that did not exhibit apatite formation may not be suitable substitutes for PR due to their weak in vivo apatite-forming ability.