Preparation And Properties Of Ag-TiO₂ Antibacterial Films On 3Y-TZP Surface

Fixed orthodontic appliance has been widely used in clinical with the characteristics of high efficiency and accuracy. Its main material is metal like stainless steel. Zirconia ceramic bas been applied in field of orthodontics because of its excellent mechanical properties, biocompatibility and its color, which is similar to natural teeth. In the course of orthodo ntic treatment, the bonding of fixed orthodontic leads to the accumulation of plaque biofilm on tooth surface which results in complication of enamel decalcification and periodontal damage. As most orthodontic patients are children which are in the high incidence of caries, plaque must be controlled in the course of orthodontic treatment. The antibacterial coating on brackets surface can play a role in controlling plaque biofilm. In this study, Ag-doped Ti O2 sol was prepared by sol- gel technology, and its thin film was obtained by a dip-coating method on the 3Y- TZP surface. The films were characterized by scanning electron microscope(SEM) and X-ray diffraction(XRD); the antibacterial property and cytotoxicity were tested by bactericidal test and MTT test.The results showed that an uniform Ti O2 film can be obtained by dip-coating method with some Ag particles on the surface. W hen the surface is coated with one time, a uniform, no crack, transparent film can be obtained. With the increase of the coating layers, in increase cracks can be found on the surface of the film. The thickness of the film is 1μm on the fracture surface of SEM image. XRD result showed that the doping of Ag can inhibit the grain growth of anatase Ti O2 with average grain size of 13.4 nm. The doping of 5at% Ag increased the photocatalytic activity, which the degradation rate of methylene blue can be reached 43% after 2h under sun light. The Ag-Ti O2 film can be get a good antibacterial propertie under the condition of no light, with a antibacterial distance of 4.5mm by zone of inhibition test. MTT test confirmed that toxicity gradation of the film was I with relative growth rate of 87%, which can be fit the standard of oral biological material. Based on the experimental results obtained in a good antibacterial properties and biological security, Ag-doped Ti O2 films can be considered for preparation of antibacterial dental zirconia brackets.