Delbem A C B, Sassaki K T, Vieira A E M, Rodrigues E, Bergamaschi M, Stock S R, Cannon M L, Xiao X, De Carlo F, Delbem A C B
Department of Pediatric Dentistry, UNESP - São Paulo State University, Araçatuba, Brasil.
Caries Res. 2009;43(5):359-65. doi: 10.1159/000231573. Epub 2009 Aug 1.
This study analyzed degrees of demineralization in bovine enamel using synchrotron microcomputed tomography (SMCT) and hardness measurements (Knoop hardness number, KHN). For 5 days, 40 bovine enamel blocks were individually subjected to a pH cycling model and treatment with fluoride dentifrices (placebo, 275, 550 and 1,100 microg F/g) diluted in deionized water twice a day. Surface hardness number and cross-sectional profiles of hardness and mineral concentration (by SMCT) were determined. Integrated hardness (KHN x microm) for sound and demineralized specimens was calculated and subtracted to give the integrated loss of hardness (DeltaKHN) for the lesions. Increasing fluoride concentration in the dentifrices led to higher values for surface hardness after pH cycling and mineral concentration (g(HAp) cm(-3)), and lower values for DeltaKHN (p < 0.05). From the present results, it may be concluded that hardness measurements revealed demineralization in all groups, which was lower in groups treated with dentifrice with a higher F concentration. SMCT and hardness measurements gave similar results in areas with higher demineralization, but diverged in areas with lower demineralization.
本研究使用同步辐射显微计算机断层扫描（SMCT）和硬度测量（努氏硬度值，KHN）分析了牛牙釉质的脱矿程度。40个牛牙釉质块分别接受为期5天的pH循环模型，并每天两次用去离子水稀释的含氟牙膏（安慰剂、275、550和1100微克氟/克）进行处理。测定了表面硬度值以及硬度和矿物质浓度的横截面轮廓（通过SMCT）。计算并减去完好和脱矿标本的综合硬度（KHN×微米），得出病变的硬度综合损失（ΔKHN）。含氟牙膏中氟浓度的增加导致pH循环后表面硬度值和矿物质浓度（克（羟基磷灰石）厘米-3）升高，而ΔKHN值降低（p<0.05）。根据目前的结果，可以得出结论，硬度测量显示所有组均有脱矿，含氟浓度较高的牙膏处理组脱矿程度较低。在脱矿程度较高区域，SMCT和硬度测量结果相似，但在脱矿程度较低区域则有所不同。
