有機酸水溶液中におけるリン酸亜鉛セメントの溶解

概要

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Dissolution of dental zinc phosphate cement was inves tigated in acetic, Iactic, oxalic and citric acid solutions with different degrees of neutralization (a) . The disso lution process was discussed based on the ion equilibrium in acid solution. Dissolution was controlled by H^+ ion concentration and/or conrplexing ability of the acid anions. The release of Zn, Mg and P decreased with in creasing a except for oxalic acid. In acid solutions with low complexing ability such as acetic acid, the unreacted ZnO and/or MgO particles dissolved preferentially by the attack of H^+ ion and most of the dissolved Zn or Mg existed as hydrated ions. While in acids with high complexing ability such as citric acid and oxalic acid, both of the phosphate matrix and the unreacted ZnO particles simultaneously dissolved at lower degrees of neutralization. Zn and Mg dissolved to form stable complexes with those acid anions. At high degrees of neutralization, a driving force for the disso lution was complexing ability of acids. The extent of the cement matrix erosion increased, with increasing tendency of the stable complex formation. Hopeite, Zn_3 (PO_4) 2 4H_2O crystallized on the surface of the cement immersed in acetic acid with a from O to 0.9 and zinc oxalate monohydrate, Zn (COO)_2 H_20 did in oxalic acid with a from O to 0.6.
社団法人日本セラミックス協会の論文
1994-05-01