Laboratory of Biomaterials, Department of Odontostomatological Science, University of Bologna, Bologna, Italy.
Dent Mater. 2011 Nov;27(11):1055-69. doi: 10.1016/j.dental.2011.07.007. Epub 2011 Aug 15.
The hypothesis was that experimental ion-leaching bioactive composites enhance remineralization of apatite-depleted dentin.
Calcium-aluminosilicate (wTC-Ba) or fluoride-containing calcium-aluminosilicate (FTC-Ba) Portland-derived mineral powders were mixed with HTP-M methacrylate HEMA/TEGDMA/PAA-based resin to prepare experimental composites. Controls were Vitrebond and Gradia Direct LoFlo. Calcium- and fluoride-release, pH of soaking water, solubility and water uptake were evaluated in deionized water using material disks (8 mm diameter and 1.6 mm thick). The apatite-formation ability (bioactivity) and the ability to remineralize previously demineralized dentin were assessed by ESEM-EDX and FTIR after soaking in a phosphate-containing solution. Human dentin slices (0.8 mm thickness) were demineralized in EDTA 17% for 2 h, placed in close contact with the material disks and immersed in a phosphate-containing solution (Dulbecco's Phosphate Buffered Saline, DPBS) to assess the ability of the materials to remineralize apatite-depleted dentin.
Only the experimental materials released calcium and basified the soaking water (released hydroxyl ions). A correlation between calcium release and solubility was observed. FTC-Ba composite released more fluoride than Vitrebond and formed calcium fluoride (fluorite) precipitates. Polyacrylate calcium complexes (between COO(-) groups of polyacrylate and released calcium ions) formed at high pH. The formation of apatite was noticed only on the experimental materials, due to the combination of calcium ions provided by the materials and phosphate from the DPBS. Apatite deposits (spherulites showing Ca and P EDX peaks and IR bands due to phosphate stretching and bending) were detected early on the experimental material disks after only 24 h of soaking in DPBS. Only the experimental composites proved to have the ability to remineralize apatite-depleted dentin surfaces. After 7 days in DPBS, only the demineralized dentin treated with the experimental materials showed the appearance of carbonated apatite (IR bands at about 1400, 1020, 600 cm(-1)). EDX compositional depth profile through the fractured demineralized dentin slices showed the reappearance of Ca and P peaks (remineralization of dentin surface) to 30-50 μm depth.
The ion-leachable experimental composites remineralized the human apatite-depleted dentin. Ion release promotes the formation of a bone-like carbonated-apatite on demineralized dentin within 7 days of immersion in DPBS. The use of bioactive "smart" composites containing reactive calcium-silicate Portland-derived mineral powder as tailored filler may be an innovative method for the biomimetic remineralization of apatite-depleted dentin surfaces and to prevent the demineralization of hypomineralized/carious dentin, with potentially great advantage in clinical applications.
假设实验性离子浸出生物活性复合材料能够增强脱矿牙本质的再矿化。
将钙铝硅酸盐（wTC-Ba）或含氟钙铝硅酸盐（FTC-Ba）波特兰衍生矿物粉末与 HTP-M 甲基丙烯酸酯 HEMA/TEGDMA/PAA 基树脂混合，制备实验性复合材料。对照组为 Vitrebond 和 Gradia Direct LoFlo。使用材料盘（直径 8 毫米，厚 1.6 毫米）在去离子水中评估钙和氟的释放、浸泡水的 pH 值、溶解度和吸水率。通过 ESEM-EDX 和 FTIR 在浸泡在含磷酸盐溶液后评估形成磷灰石的能力（生物活性）和先前脱矿化牙本质的再矿化能力。用人牙本质片（0.8 毫米厚）在 EDTA 17%中脱矿化 2 小时，与材料盘紧密接触，并浸入含磷酸盐的溶液（杜尔贝科磷酸盐缓冲盐水，DPBS）中，以评估材料对脱矿化牙本质的再矿化能力。
只有实验材料释放钙并使浸泡水碱化（释放羟基离子）。观察到钙释放与溶解度之间存在相关性。FTC-Ba 复合材料释放的氟化物多于 Vitrebond，并形成氟化钙（萤石）沉淀物。在高 pH 值下形成聚丙烯酸钙复合物（在聚丙烯酸的 COO(-)基团和释放的钙离子之间）。仅在实验材料上观察到磷灰石的形成，这是由于材料提供的钙离子和 DPBS 中的磷酸盐的结合。在 DPBS 中浸泡仅 24 小时后，仅在实验材料盘上即可检测到磷灰石沉积物（显示 Ca 和 P EDX 峰和由于磷酸盐伸缩和弯曲而产生的 IR 带的球形磷灰石）。仅实验复合材料被证明具有再矿化脱矿化牙本质表面的能力。在 DPBS 中孵育 7 天后，仅用实验材料处理的脱矿化牙本质显示出碳酸磷灰石的出现（约 1400、1020、600 cm(-1)处的 IR 带）。通过断裂的脱矿化牙本质切片的 EDX 组成深度剖面显示，在 30-50 μm 的深度重新出现 Ca 和 P 峰（牙本质表面的再矿化）。
可浸出离子的实验性复合材料使人类脱矿化的牙本质再矿化。离子释放促进了在 DPBS 中浸泡 7 天内脱矿化牙本质上形成类似于骨的碳酸磷灰石。使用含有反应性钙硅波特兰衍生矿物粉末的生物活性“智能”复合材料作为定制填料可能是一种仿生再矿化脱矿化牙本质表面和防止低矿化/龋齿牙本质脱矿化的创新方法，在临床应用中具有潜在的巨大优势。
