Piracicaba Dental School, University of Campinas, Piracicaba, Brazil.
Piracicaba Dental School, University of Campinas, Piracicaba, Brazil,
Caries Res. 2019;53(3):296-304. doi: 10.1159/000493099. Epub 2018 Oct 12.
We aimed to evaluate whether radiotherapy causes changes in the mineral composition, hardness, and morphology of enamel and dentin of primary teeth.
Thirty specimens of primary teeth were subjected to radiotherapy. At baseline and after 1,080, 2,160, and 3,060 cGy, the specimens were subjected to microhardness, FT-Raman spectroscopy, and scanning electron microscopy (SEM) analysis. The pH of artificial saliva was determined, as were the calcium and phosphate concentrations. The data were subjected to the Shapiro-Wilk normality test, showed a nonnormal distribution, and were compared by the Kruskal-Wallis test.
The results showed that the microhardness of the enamel surface decreased after 2,160 cGy (281.5 ± 58 kgf/mm2) when compared to baseline (323.6 ± 59.5 kgf/mm2) (p = 0.045). For dentin, the surface hardness decreased after 1,080 cGy (34.9 ± 11.4 kgf/mm2) and 2,160 cGy (26 ± 3.5 kgf/mm2) when compared to baseline (56.5 ± 7.7 kgf/mm2) (p < 0.0001). The mineral and organic contents of phosphate (p < 0.0001), carbonate (p < 0.0001), amide (p = 0.0002), and hydrocarbons (p = 0.0031) of enamel decreased after 3,060 cGy (5,178 ± 1,082, 3,868 ± 524, 999 ± 180, and 959 ± 168 kgf/mm2, respectively). For dentin, we noticed a growing increase in phosphate v2, amide, and hydrocarbon content after 1,080 cGy (8,210 ± 2,599, 5,730 ± 1,818, and 6,118 ± 1,807 kgf/mm2, respectively) and 2,160 cGy (1,0071 ± 2,547, 7,746 ± 1,916, and 8,280 ± 2,079 kgf/mm2, respectively) and a reduction after 3,060 cGy (6,782 ± 2,175, 3,558 ± 1,884, and 3,565 ± 1,867 kgf/mm2, respectively) (p < 0.0001). SEM images showed cracks on enamel and degradation of peritubular dentin.
We concluded that radiotherapy caused a reduction in surface hardness, changed mineral and organic composition, and promoted morphological changes on the enamel and dentin of primary teeth.
评估放射治疗是否会导致乳牙釉质和牙本质的矿物质组成、硬度和形态发生变化。
对 30 颗乳牙标本进行放射治疗。在基线时以及在 1080、2160 和 3060 cGy 后，对标本进行显微硬度、傅里叶变换拉曼光谱和扫描电子显微镜（SEM）分析。测定人工唾液的 pH 值以及钙和磷酸盐浓度。数据经过 Shapiro-Wilk 正态性检验，呈非正态分布，采用 Kruskal-Wallis 检验进行比较。
结果显示，与基线时（323.6 ± 59.5 kgf/mm2）相比，釉质表面的显微硬度在 2160 cGy 后（281.5 ± 58 kgf/mm2）下降（p = 0.045）。对于牙本质，表面硬度在 1080 cGy 和 2160 cGy 后（分别为 34.9 ± 11.4 kgf/mm2 和 26 ± 3.5 kgf/mm2）低于基线时（56.5 ± 7.7 kgf/mm2）（p < 0.0001）。釉质中磷酸盐（p < 0.0001）、碳酸盐（p < 0.0001）、酰胺（p = 0.0002）和碳氢化合物（p = 0.0031）的矿物和有机含量在 3060 cGy 后（分别为 5178 ± 1082、3868 ± 524、999 ± 180 和 959 ± 168 kgf/mm2）下降。对于牙本质，我们注意到在 1080 cGy 和 2160 cGy 后，磷酸盐 v2、酰胺和碳氢化合物的含量逐渐增加（分别为 8210 ± 2599、5730 ± 1818 和 6118 ± 1807 kgf/mm2），而在 3060 cGy 后减少（分别为 6782 ± 2175、3558 ± 1884 和 3565 ± 1867 kgf/mm2）（p < 0.0001）。SEM 图像显示釉质上出现裂缝，小管周围牙本质退化。
我们得出结论，放射治疗导致乳牙釉质和牙本质的表面硬度降低，矿物质和有机组成发生变化，并促进形态发生变化。
