A bi-layered coating of nanofluorapatite/nanochitosan to improve antimicrobial and biological properties of zirconia-based dental implants.

Abstract

Yttria-stabilized zirconia has mechanical properties akin to titanium dental implants but lacks osseointegration properties. A bi-layered nano-fluorapatite/nano-chitosan (nFA/nCS) coating was synthesized to improve the osseointegration potential and antimicrobial properties of zirconia. Zirconia discs were coated with bi-layered nFA/nCS using the sol-gel route. The integrity of the coating was tested by x-ray diffraction, atomic force microscopy and field emission scanning electron microscopy-energy-dispersive spectroscopy. Adhesion of the coating to zirconia was evaluated by the adhesive tape test and ultrasonic vibration. By measuring the optical contact angle, differences in the wettability of the coated and non-coated samples were assessed. Antimicrobial activity was investigated againstStaphylococcus aureusandEschericiha coliand cytotoxicity examined using osteoblast-like cells. The bi-layered nFA/nCS coating was 9.26 μm thick and exhibited acceptable adhesion strength (0.50 ± 1.1 N mm^-1) to zirconia and greater resistance to ultrasonic-induced delamination than a single layer of nFA coating; the water contact angle decreased to 5° and the surface roughness increased to 121.3 nm. The coating decreased the count of both bacterial strains and was not cytotoxic to mammalian cells. We conclude that the nFA/nCS coating exhibited acceptable adhesion and enhanced bioactivity and antimicrobial activity, rendering it a potential material for replacing titanium dental implants. Functionalizing zirconia with nFA/nCS is a cost-effective alternative to titanium implants. While still at an early stage of research, nFA/nCS-coated zirconia implants have the potential to widen public availability and increase access to implant treatment.