Investigation of bioactivity, biocompatibility, and antibacterial properties of a hydroxyapatite-enhanced nanocomposite for dental applications

The prolonged setting duration of mineral trioxide aggregate (MTA) constitutes one of its principal limitations. In contrast, Nano Fast Cement (NFC) emerges as an innovative nanocomposite characterized by a rapid setting time. To develop an outstanding dental filler, hydroxyapatite nanoparticles (NHA) were incorporated into NFC to evaluate their effects on setting time, biocompatibility, bioactivity, and antibacterial properties. Specimens containing 0, 10, and 20 weight% (W%) hydroxyapatite were subjected to assessment utilizing the MTT assay for cytotoxicity, the Gilmore needle for measuring setting time, scanning electron microscopy (SEM) and X-ray diffraction (XRD) for microstructural and phase analyses, as well as antibacterial evaluations against Enterococcus faecalis (PTCC 1394). Phase and microstructural investigations confirmed the formation of hydroxyapatite. The addition of 10 and 20 W% hydroxyapatite significantly improved the specimens’ bioactivity while reducing toxicity by 20%. An increase in hydroxyapatite content corresponded with a greater enhancement in bioactivity and a further reduction in toxicity. These findings indicate that the addition of NHA did not detrimentally affect the physical properties of NFC; rather, it augmented the filler’s bioactivity in vitro. Furthermore, the nanocomposite containing a higher concentration of NHA exhibited superior inhibition of E. faecalis compared to NFC in minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) (p-value < 0.001).