目的探讨纳米羟基磷灰石对龋病的预防效果及其可能的防龋机制。方法于大鼠口腔内连续接种变形链球菌(ATCC 25135)4 d后,用纳米羟基磷灰石含漱液对实验组大鼠进行含漱,每日早晚各一次,持续60d。鼠龄90 d时处死全部大鼠,并作扫描电镜。结果实验组大鼠口腔内变形链球菌含量明显低于对照组,龋齿评分也明显低于对照组。结论纳米羟基磷灰石具有预防龋病发生,有效抑制变形链球菌增殖,促进牙釉质表面再矿化作用。 Objective To investigate the preventive effect of nano-hydroxyapatite on dental caries and its possible anti-caries mechanism. Methods Four weeks after oral inoculation of Streptococcus mutans (ATCC 25135) in rat oral cavity, rats in the experimental group were rinsed with nano-hydroxyapatite gargle. All rats were sacrificed at 90 days of age and scanned by SEM. Results The content of Streptococcus mutans in the oral cavity of experimental group was significantly lower than that of the control group, and the score of dental caries was also significantly lower than that of the control group. Conclusion Nano-hydroxyapatite can prevent the occurrence of dental caries, effectively inhibit the proliferation of Streptococcus mutans and promote the remineralization of enamel surface.