Bioactive glass coating of orthodontic material for the recovery of mechanical properties of etched enamel

This study investigated the effects of a bioactive glass coating of orthodontic material on the recovery of the mechanical properties of etched enamel via remineralization in artificial saliva. Alumina disks were coated with bioactive glass using radiofrequency magnetron sputtering. Human enamel blocks were etched with phosphoric acid, fixed on a specimen stage with alumina disks, and then immersed in artificial saliva for 3 months. Nanoindentation testing of the enamel surfaces was conducted before and after etching and during the immersion. Bioactive-glass-coated alumina disks were immersed individually in artificial saliva for 1 week and the deposited crystals were analyzed using scanning electron microscopy and X-ray diffraction (XRD). The mechanical properties of the etched enamel specimens immersed with bioactive-glass-coated disks recovered significantly compared to those with the non-coated disks. The formation of needle-like structures was observed on the surfaces of the bioactive-glass-coated alumina disks after immersion for 1 week and the XRD pattern of the crystals confirmed that they consisted of calcium phosphate. Bioactive glass coating of alumina can accelerate the remineralization of etched enamel.