Söderholm K J, Mukherjee R, Longmate J
Department of Dental Biomaterials, University of Florida, Gainesville 32610-0446, USA.
J Dent Res. 1996 Sep;75(9):1692-9. doi: 10.1177/00220345960750091201.
Though dental composite materials leach filler elements when stored in distilled water, it is not known whether similar leaching occurs in saliva. The hypothesis to be tested was that due to ion exchange occurring at the filler surfaces, more filler elements leach from composites stored in a salt solution simulating saliva than from composites stored in distilled water. Another aim was to determine how matrix selection, filler composition, and filler silanization affect filler leachability of composites after storage in the simulated saliva and water media. We made 128 batches of experimental composites. Half of these used a bis-GMA/TEGDMA matrix and the other a UEDMA/TEGDMA matrix. Either silica or barium glass filler particles were incorporated into these matrices. Filler silanization was followed by a filler drying at 60 degrees C for 24 h. Half of the silanized particles received an additional heat treatment for 1 h at 110 degrees C in vacuum. One specimen per batch was stored in distilled water and the other in artificial saliva at 37 degrees C. After each 30-day interval for one year, the specimens were transferred to either freshly distilled water or newly mixed artificial saliva. The "old" solutions were analyzed by ICP for determination of the Si, Ba, and Al concentrations. Analysis of variance revealed that storage solution, filler composition, and total time in the storage solution had strong effects on the leachability (p < 0.0001 in all cases). The average monthly leakage of Si for quartz-filled composites was 0.22 +/- 0.20 microgram/mL (distilled water) and 2.80 +/- 1.20 microgram/mL (artificial saliva). For barium-glass-filled composites, the corresponding Si leaching values were 0.73 +/- 0.48 microgram/mL and 5.00 +/- 2.20 microgram/mL. The monthly means of the barium leaching values were 2.00 +/- 1.00 microgram/mL (distilled water) and 3.10 +/- 1.80 microgram/mL (artificial saliva). The large difference between leaching in artificial saliva and in distilled water, as well as the interaction between storage medium and filler, cast doubt on the clinical relevance of in vitro studies using distilled water.
尽管牙科复合材料在蒸馏水中储存时会浸出填充元素，但尚不清楚在唾液中是否会发生类似的浸出。待检验的假设是，由于在填料表面发生离子交换，与储存在蒸馏水中的复合材料相比，储存在模拟唾液的盐溶液中的复合材料浸出的填料元素更多。另一个目的是确定基质选择、填料组成和填料硅烷化如何影响复合材料在模拟唾液和水介质中储存后的填料浸出性。我们制备了128批实验复合材料。其中一半使用双酚A缩水甘油醚/三乙二醇二甲基丙烯酸酯（bis-GMA/TEGDMA）基质，另一半使用聚氨酯二甲基丙烯酸酯/三乙二醇二甲基丙烯酸酯（UEDMA/TEGDMA）基质。将二氧化硅或钡玻璃填料颗粒掺入这些基质中。填料硅烷化后，在60℃下干燥24小时。一半的硅烷化颗粒在真空中于110℃额外热处理1小时。每批取一个样品储存在蒸馏水中，另一个储存在37℃的人工唾液中。在一年中的每个30天间隔后，将样品转移到新鲜蒸馏水中或新配制的人工唾液中。通过电感耦合等离子体发射光谱法（ICP）分析“旧”溶液，以测定硅、钡和铝浓度。方差分析表明，储存溶液、填料组成和在储存溶液中的总时间对浸出性有显著影响（在所有情况下p < 0.0001）。对于石英填充的复合材料，硅的平均每月泄漏量在蒸馏水中为0.22±0.20微克/毫升，在人工唾液中为2.80±1.20微克/毫升。对于钡玻璃填充的复合材料，相应的硅浸出值分别为0.73±0.48微克/毫升和5.00±2.20微克/毫升。钡浸出值的每月平均值在蒸馏水中为2.00±1.00微克/毫升，在人工唾液中为3.10±1.80微克/毫升。人工唾液和蒸馏水中浸出情况的巨大差异，以及储存介质和填料之间的相互作用，让人对使用蒸馏水的体外研究的临床相关性产生怀疑。
