Objective: To compare the anti-caries effect and safety of Er:YAG laser combined with fluoride and methylene blue-photodynamic therapy (MB-PDT).
Methods: A total of 28 rat dental caries models were established and randomly divided into seven groups: photodynamic therapy (PDT) group, laser combined with fluoride group, laser group, sodium fluoride group, and 0.9% saline control group. Spectrophotometric optical density was used to reflect the growth of Streptococcus mutans. Laser-induced fluorescence diagnostic (LF) instrument was utilized to detect the demineralization degree of dental caries. Histopathological sections were employed to observe the damage of dental pulp and buccal mucosa.
Results: The optical density (OD) value of the PDT and combination groups was significantly lower than that of other treatment groups (P<0.05). An increase in LF value and demineralization occurred in varying degrees with different treatment methods. Histopathological observation showed that pulp and buccal mucosa injury was more obvious in the combination group of 70 mw·cm⁻² and Er:YAG laser group compared with other groups.
Conclusions: Under the same parameters, the combined group and PDT have good germicidal efficacy, but PDT has fewer adverse reactions and less damage. It is an effective and safe method for caries prevention.
目的 比较Er:YAG激光-氟化钠联合法与亚甲基蓝-光动力疗法（MB-PDT）的防龋效果及安全性。方法 建立28只大鼠龋齿模型，随机分成7组：不同功率密度的光动力疗法（PDT）组、激光+氟化钠联合组、激光组、氟化钠组和0.9%生理盐水组。分光光度法检测变异链球菌生长抑制情况；激光荧光诊断仪（LF）检测龋损脱矿程度；组织病理观察牙髓及颊黏膜损伤状况。结果 PDT组与激光+氟化钠联合组光密度值明显低于其他处理组（P<0.05）；不同处理方法均可使LF值上升，出现不同程度的脱矿；组织病理学观察，70 mw·cm⁻²的联合组和Er:YAG激光组存在牙髓及颊黏膜损伤。结论 相同参数下，联合组与PDT均有良好的杀菌效果，但PDT不良反应少、损伤小，是一种高效且安全的防龋手段。.
Keywords: Er:YAG laser; fluoride; histopathology; photodynamic therapy.