Evaluation of Morphology, Degradation, and Biocompatibility of Fluorideapatite–Bioactive Glass (453P4) Nanocomposites

Bioceramic nanocomposites are increasingly explored for bone regeneration and dental applications due to their tunable bioactivity and mechanical properties. This study investigates the physicochemical properties, degradation behavior, bioactivity, mechanical performance, cytocompatibility, and antibacterial activity of fluorapatite-based nanocomposite ceramics reinforced with 10, 20, and 30 wt.% of S53P4 bioglass synthesized via the sol-gel method. The composites were characterized for degradation by monitoring weight loss and pH changes, while bioactivity was assessed through apatite layer formation in simulated body fluid (SBF). The release of silicon and fluoride ions was quantified using inductively coupled plasma spectroscopy and a fluoride-selective electrode, respectively. Cytocompatibility was examined via MTT assay on osteoblast-like cells over 1 to 7 days. Antibacterial activity was assessed against Streptococcus mutans using colony count reduction. Results showed that, increasing the S53P4 content enhanced degradation and bioactivity, reflected in higher ion release and more significant apatite formation, while compressive strength increased proportionally with the bioglass content. MTT assays demonstrated favorable cytocompatibility, with no evidence of cytotoxicity, although cell viability slightly decreased after 7 days compared to day 1. Antibacterial tests confirmed a reduction in S. mutans colonies with higher glass phase percentages, indicating improved antibacterial potential. These findings highlight the potential of fluorapatite–S53P4 nanocomposites as promising biomaterials for bone regeneration and dental applications.