Lippert F, Lynch R J M
Department of Preventive and Community Dentistry, Oral Health Research Institute, Indiana University School of Dentistry, 415 Lansing St, Indianapolis, IN 46202, USA.
GlaxoSmithKline, St. George's Avenue, Weybridge KT13 0DE, United Kingdom.
Arch Oral Biol. 2014 Jul;59(7):704-10. doi: 10.1016/j.archoralbio.2014.04.005. Epub 2014 Apr 21.
The aims of the present laboratory study were twofold: a) to investigate the suitability of Knoop and Vickers surface microhardness (SMH) in comparison to transverse microradiography (TMR) to investigate early enamel caries lesion formation; b) to compare the kinetics of caries lesion initiation and progression between human and bovine enamel.
Specimens (90×bovine and 90×human enamel) were divided into six groups (demineralization times of 8/16/24/32/40/48h) of 15 per enamel type and demineralized using a partially saturated lactic acid solution. SMH was measured before and after demineralization and changes in indentation length (ΔIL) calculated. Lesions were characterized using TMR. Data were analyzed (two-way ANOVA) and Pearson correlation coefficients calculated.
ΔIL increased with increasing demineralization times but plateaued after 40h, whereas lesion depth (L) and integrated mineral loss (ΔZ) increased almost linearly throughout. No differences between Knoop and Vickers SMH in their ability to measure enamel demineralization were observed as both correlated strongly. Overall, ΔIL correlated strongly with ΔZ and L but only moderately with the degree of surface zone mineralization, whereas ΔZ and L correlated strongly. Bovine demineralized faster than human enamel (all techniques).
Lesions in bovine formed faster than in human enamel, although the resulting lesions were almost indistinguishable in their mineral distribution characteristics. Early caries lesion demineralization can be sufficiently studied by SMH, but its limitations on the assessment of the mineral status of more demineralized lesions must be considered. Ideally, complementary techniques to assess changes in both physical and chemical lesion characteristics would be employed.
本实验室研究有两个目的：a）与横向显微放射摄影术（TMR）相比，研究努氏硬度和维氏表面显微硬度（SMH）在研究早期釉质龋损形成方面的适用性；b）比较人类和牛牙釉质龋损起始和进展的动力学。
将样本（90个牛牙釉质样本和90个人牙釉质样本）按脱矿时间分为六组（8/16/24/32/40/48小时），每种牙釉质类型各15个，使用部分饱和乳酸溶液进行脱矿。在脱矿前后测量SMH，并计算压痕长度变化（ΔIL）。用TMR对病变进行表征。对数据进行分析（双向方差分析）并计算皮尔逊相关系数。
ΔIL随脱矿时间增加而增加，但在40小时后趋于平稳，而病变深度（L）和累计矿物质损失（ΔZ）几乎呈线性增加。在测量牙釉质脱矿能力方面，未观察到努氏硬度和维氏硬度之间的差异，因为两者相关性都很强。总体而言，ΔIL与ΔZ和L相关性很强，但与表面区域矿化程度相关性中等，而ΔZ和L相关性很强。牛牙釉质脱矿速度比人牙釉质快（所有技术均显示如此）。
牛牙釉质中的病变形成速度比人牙釉质快，尽管最终病变的矿物质分布特征几乎无法区分。SMH可充分研究早期龋损病变的脱矿情况，但必须考虑其在评估脱矿程度更高病变的矿物质状态方面的局限性。理想情况下，应采用互补技术来评估病变物理和化学特征的变化。
