Schmidlin Patrick R, Zehnder Matthias, Imfeld Thomas, Swain Michael V
Department of Preventive Denstistry, Periodontology and Cariology, Center for Dental and Oral Medicine,University of Zurich, Switzerland.
J Biomed Mater Res B Appl Biomater. 2007 Oct;83(1):199-205. doi: 10.1002/jbm.b.30784.
The aim of the current in vitro study was to evaluate the influence of three lining materials with a reported mineralizing capacity on hardness and elasticity of demineralized dentin. Four standardized microcavities were prepared in exposed dentin surfaces of 16 extracted human molars each. Dentin was demineralized in 0.5M EDTA for 2 h. One microcavity was left empty. The others were filled with a resin-modified glass ionomer cement (RMGIC), a bioactive glass S53P4 suspension, and a prototype Ca-PO(4) cement. Teeth were then immersed in deionized water or simulated oral fluid. After 3 weeks, hardness and composite elastic modulus of the dentin subjacent to the microcavities were assessed under wet conditions using the ultramicroindentation system (UMIS). After immersion in deionized water, there was no significant improvement of the mechanical properties of dentin irrespective of the material applied beforehand, indicating a lack of direct material effects. Exposure to simulated oral fluid resulted in significantly (p < 0.05) higher hardness and composite elastic modulus values of the dentin subjacent to empty microcavities and counterparts lined with bioactive glass compared to corresponding dentin under the RMGIC. UMIS profiles showed little variance.
当前这项体外研究的目的是评估三种据报道具有矿化能力的衬里材料对脱矿牙本质硬度和弹性的影响。在16颗拔除的人磨牙的暴露牙本质表面上，每颗牙制备四个标准化微腔。牙本质在0.5M乙二胺四乙酸（EDTA）中脱矿2小时。一个微腔保持空的状态。其他微腔分别填充树脂改性玻璃离子水门汀（RMGIC）、生物活性玻璃S53P4悬液和一种原型磷酸钙（Ca-PO₄）水门汀。然后将牙齿浸入去离子水或模拟口腔液中。3周后，使用超微压痕系统（UMIS）在潮湿条件下评估微腔下方牙本质的硬度和复合弹性模量。浸入去离子水后，无论预先应用何种材料，牙本质的力学性能均无显著改善，表明缺乏直接的材料效应。与RMGIC下方的相应牙本质相比，暴露于模拟口腔液导致空微腔和衬有生物活性玻璃的对应微腔下方牙本质的硬度和复合弹性模量值显著更高（p < 0.05）。UMIS剖面图显示差异很小。
