Love W B, Biswas S
University of Manitoba, Faculty of Dentistry, Winnipeg, Canada.
J Prosthet Dent. 1991 Sep;66(3):356-60. doi: 10.1016/0022-3913(91)90263-v.
Aqueous solutions of some denture adhesives will produce a pH below the critical pH of hydroxyapatite. This article measured the pH of selected denture adhesives. The pH and buffering capacity were established for 10 readily available denture adhesives. The pH was determined from samples in dilutions of 1:10, 1:20, 1:30, and 1:40 denture adhesive to deionized water. A glass pH electrode coupled to a pH meter was used for pH determination. Six of the 10 denture adhesives tested had pH values below the critical pH of hydroxyapatite. This pH was maintained for the 2-hour duration of the testing. Prolonged contact of denture adhesive and tooth substances may dissolve hydroxyapatite crystals. Samples of denture adhesives to determine buffering capacity were prepared in a ratio of 1:20 by weight of denture adhesive to deionized water. Another series of samples was prepared in a ratio of 1:20 by weight of adhesive to freshly cannulated submandibular saliva. The pH was determined at the 24-hour time interval. Samples were then titrated with 0.1N sodium hydroxide solution in the presence of phenolphthalein. The same denture adhesives demonstrated low pH values at the 2-hour and 24-hour time intervals. These samples tended to be well buffered. It is recommended that denture adhesives with low pH values not be used in an environment with natural teeth or remnants of natural teeth.
一些假牙粘合剂的水溶液会产生低于羟基磷灰石临界pH值的pH值。本文测量了选定假牙粘合剂的pH值。测定了10种容易获得的假牙粘合剂的pH值和缓冲能力。pH值是通过将假牙粘合剂与去离子水按1:10、1:20、1:30和1:40的比例稀释后取样测定的。使用与pH计相连的玻璃pH电极进行pH值测定。所测试的10种假牙粘合剂中有6种的pH值低于羟基磷灰石的临界pH值。在测试的2小时期间内该pH值保持不变。假牙粘合剂与牙齿物质的长时间接触可能会溶解羟基磷灰石晶体。用于测定缓冲能力的假牙粘合剂样品按假牙粘合剂与去离子水1:20的重量比制备。另一系列样品按粘合剂与新鲜插管的下颌下唾液1:20的重量比制备。在24小时间隔时测定pH值。然后在酚酞存在下用0.1N氢氧化钠溶液滴定样品。相同的假牙粘合剂在2小时和24小时间隔时显示出低pH值。这些样品往往具有良好的缓冲作用。建议不要在有天然牙齿或天然牙齿残根的环境中使用低pH值的假牙粘合剂。
