Magnetic Hydroxyapatite-Coated Iron–Chromium Microspheres for Dental Surface Polishing and Plaque Removal

This research aimed to engineer magnetic hydroxyapatite-coated iron–chromium (HAp–FeCr) microspheres to enhance dental surface polishing and plaque elimination. Utilizing a tailored sol–gel approach, the HAp–FeCr microspheres were synthesized and exhaustively characterized via scanning electron microscopy, energy-dispersive X-ray spectroscopy, ζ-potential, X-ray diffractometry, and X-ray photoelectron spectroscopy methodologies. Key findings showcased that these microspheres retained their magnetic properties post-HAp coating, as evidenced by the magnetization curves. An innovative magnetic polishing system was developed, incorporating these microspheres and a 2000 rpm magnet. Comparative evaluations between traditional air-powder polishing and the proposed magnetic technique demonstrated the latter's superiority. Notably, the magnetic polishing led to a substantial reduction in dental plaque on the tooth surface, decreasing bacterial adhesion and early biofilm formation by Streptococcus gordonii and Lactobacillus acidophilus, where the most pronounced effects were observed in samples with elevated HAp content. A significant 60% reduction in dental plaque was achieved with the magnetic method relative to air-powder polishing. Furthermore, the HAp–FeCr microspheres' biocompatibility was verified through cytotoxicity tests and animal studies. In essence, the magnetic HAp–FeCr microspheres present a novel and efficient strategy for dental treatments, holding immense potential for improving oral health.