Study on antibacterial and fluoride-releasing properties of
• Fluorine-doped nano-zirconia (F-ZrO2) powders were synthesized successfully by the chemical precipitation method.

• F-ZrO2 showed excellent antibacterial effect through releasing fluoride ions. The novel composite resin (CR) with F-ZrO2 fillers was prepared.

• The CR did release fluoride ions continuously within 28 days. And the fluoride release can be increased in a short time after fluoride-recharging treatment.

• The CR exhibited effective antibacterial properties and no obvious cytotoxicity.

A novel composite resin (CR) with fluorine-doped nano-zirconia (F-ZrO2) fillers was developed as an antibacterial restorative material. This article described the synthesis and investigated the fluoride release, antibacterial property and cytotoxicity of the novel CR.

F-ZrO2 powders with different fluorine contents were synthesized by chemical precipitation method and characterized by XRD, SEM, and TEM-EDS. The content and release of fluoride were also determined. 20% F-ZrO2 powers were selected to develop the novel CRs. The fluoride release from the novel CRs during 28 days was recorded. The antibacterial property of the novel CRs was investigated with a direct contact test (DCT) and metabolic activity test (CCK8). The cytotoxicity of the CRs was also evaluated here.

F-ZrO2 powders with different fluorine contents were obtained. The fluoride release increased with increasing of the fluoride content. Through the antibacterial performance evaluation, 20% F-ZrO2 powders, which exhibit the best antibacterial property, were selected as the fillers for preparing the novel CR. The novel CR with F-ZrO2 fillers exhibited an effective antibacterial effect. Compared with the control group, the antibacterial rates of FZ-25, FZ-50, and FZ-75 were 51.65%, 54.14%, and 66.80%, respectively. No obvious cytotoxicity of the novel CR was detected in this study.

The novel CR with continuous fluoride release and proper antibacterial property is expected to be used as an antibacterial material to reduce secondary caries.