Dickens Sabine H, Flaim Glenn M, Takagi Shozo
American Dental Association Health Foundation, National Institute of Standards and Technology, Paffenbarger Research Center, 100 Bereau Dr Stop 8546, Gaithersburg, MD 20899-8546, USA.
Dent Mater. 2003 Sep;19(6):558-66. doi: 10.1016/s0109-5641(02)00105-7.
This study examined strength and bioactive (remineralizing) properties of a powder/liquid formulation (Cement I) and a more practical two-paste formulation (Cement II) of a fluoride-releasing resin-based Ca-PO(4) cement.
For the remineralization potential, the dissolution of calcium, total ionic phosphate and fluoride from set cement specimens were determined in buffered saline and saliva-like solution (SLS). Artificial caries lesions were produced on coronal dentin of extracted human molars. On each tooth, two defined areas were coated, one with a composite resin (calcium-free control), the other with either Cement I or II. After incubation in SLS, the mineral loss under the cement was analyzed by digitized microradiography and compared to that under the control.
The diametral tensile strength of Cement II of approximately 30 MPa after 24 h and 23 MPa after 4 weeks was 2 to 3 times higher than that of Cement I (ANOVA, t-test, p<0.05). Calculations of the ion-activity products and Gibb's free energy from solution ion concentrations indicated a significant potential for the formation of fluor- and/or hydroxyapatite. Concurrently, both cements caused increases of 47% (Cement I) and 38% (Cement II) in the lesion mineral content over that underneath the corresponding controls.
These in vitro results suggest that the stronger Cement II could serve as a restoration-supporting lining material and could remineralize dentin in areas where complete removal of carious tissue is contra-indicated.
本研究检测了一种含氟树脂基磷酸钙骨水泥的粉末/液体配方（骨水泥I）和一种更实用的双糊剂配方（骨水泥II）的强度及生物活性（再矿化）特性。
对于再矿化潜力，在缓冲盐水和类唾液溶液（SLS）中测定固化骨水泥标本中钙、总离子磷酸盐和氟化物的溶解情况。在拔除的人磨牙的冠部牙本质上制备人工龋损。在每颗牙齿上，两个确定的区域分别涂布，一个用复合树脂（无钙对照），另一个用骨水泥I或骨水泥II。在SLS中孵育后，通过数字化显微放射摄影分析骨水泥下方的矿物质流失，并与对照下方的情况进行比较。
骨水泥II在24小时后的径向拉伸强度约为30MPa，4周后为23MPa，比骨水泥I高2至3倍（方差分析、t检验，p<0.05）。根据溶液离子浓度计算离子活度积和吉布斯自由能表明，有显著的形成氟磷灰石和/或羟基磷灰石的潜力。同时，两种骨水泥使病变矿物质含量比相应对照下方增加了47%（骨水泥I）和38%（骨水泥II）。
这些体外结果表明，强度更高的骨水泥II可作为修复支持衬里材料，并且可以在禁忌完全去除龋坏组织的区域使牙本质再矿化。
