Objective: This study aims to evaluate the effects of Pinus massoniana needle extract (PMNE) on inhibiting demineralization of root dentin.
Methods: Root dentin blocks were randomly divided into distilled deionized water (DDW) group, fluoride sodium (NaF) group, and 4%, 8% and 12% PMNE groups according to the experimental solution used in the process of pH cycling in each group. All specimens in each group experienced pH cycling for 8 d. The dentin mineral density (DMD) of the normal dentin and demineralized dentin and their D-value (ΔDMD) were determined using micro computed tomography. The morphology of dentin surface after pH cycling was also observed using a scanning electron microscope.
Results: The ΔDMD values in all PMNE groups and the NaF group were considerably lower than the ΔDMD in the DDW group (P<0.05). The ΔDMD values of the 8% and 12% PMNE groups had no difference (P>0.05), both of which were lower than the ΔDMD in the 4% PMNE group and higher than that in the NaF group (P<0.05). The dentin tubules were partly opened in the PMNE groups. The opening degrees of the dentin tubule in PMNE groups were significantly less and smaller than the opening degree in the DDW group and were larger than that in the NaF group.
Conclusions: PMNE can inhibit the deminera-lization of root dentin and can slow down the reduction in DMD. PMNE has the potential to prevent caries, and 8% PMNE can effectively inhibit dentin demineralization.
目的 评价马尾松松针提取物（PMNE）抑制根面牙本质脱矿的效果。方法 将根面牙本质块根据pH循环中所用实验溶液随机分为去离子蒸馏水（DDW）组，氟化钠（NaF）组，4%、8%和12%PMNE组，试件进行为期8 d的pH循环。显微CT选区测定各组未脱矿牙本质和脱矿牙本质的牙本质矿物密度（DMD）及两者DMD差值（ΔDMD），扫描电镜下观察pH循环后牙本质表面形貌。结果 PMNE各组和NaF组ΔDMD均显著低于DDW组（P<0.05），且8% PMNE组和12%PMNE组ΔDMD组间差异无统计学意义（P>0.05），均显著低于4%PMNE组，高于NaF组（P<0.05）。扫描电镜见PMNE组牙本质小管不全暴露，小管开口程度明显小于DDW组，大于NaF组。结论 PMNE可抑制根面牙本质脱矿，减缓酸对DMD的降低，具有一定的抗龋活性。8%PMNE即可达到较好抑制脱矿的效果。.
Keywords: Pinus massoniana needle extract; demineralization; dentin; mineral density; root caries.