Studies on Soluble Elements and Solubility of Dental Cement (1)

Abstract

Various improvements have been introduced in dental cement recently, and its physical properties have been developed to a great degree. But still there remains room for improvement as to after-settled dimensional changes and solubilities. Especially, the solubilities of cement has been considered to be one of the causes of secondary caries[1]. That is, the solubility of cement, the smaller the better, should be further examined. Many reports have been published regarding the solubility of dental cement, and the general conception is that the solubility varies to a great degree in accordance with the kinds of solutions in which cement is soaked[2]. That is, as to the solubility in the oral cavity, zinc phosphate cement is larger than silicate cement, while in the distilled water silicate cement is larger. Again, according to SKINNER, et al.[1] and NORMAN et al.[3], the solubility of cement in the organic acid solutions is very large compared with in the water. again, the solubility increases proportionally to the soaking time. KOHATA et al[4] say that the solubility of zinc phosphate cement soaked in the distilled water for a day is 0.08-0.12%), and 0.14-0.18% for 7 days. Carboxylate cement shows the minimum 0.04% and the maximum 0.17% in a day soaking, and the solubility of silicate cement is very large[5-8]. Generally the soluble amount of cement is determined by soaking the set products of cement in solutions to measure the whole dissolved amount by the gravimetric method. But in case the soluble amount is very small, the gravimetric method becomes uncertain, the balance reaching its measuring limit. Again, these methods cannot make the soluble elements determined. Now, from the above-mentioned viewpoints, the authors try to make out the main soluble elements of cement and their amounts, and from the results obtained , perform the present studies to establish the basis for developing the cement with small solubilities. * Studies on the Dental Cement 25 School of Dentistry, Tokyo.

Surface analysis of cements after having been immersed in water - Surface state and elementary analysis of zinc phosphate cement and carboxylate cement.

“…This matrix is believed to be the carboxylate of Zn and Mg. However, because the peak is smaller than that for Mg observed at A, and also because of the soluble element and its solubilities [7], the carboxylate of Mg is believed to be unstable. After all, Mg and Ca in zinc phosphate cement and carboxylate cement create either phosphate or carboxylate.…”

“…This indicates that B is a matrix consisting of Zn, Al and a very small amount of Mg, each of which are thought to be phosphates. However, the Ca in the matrix [7] was not detected. Fig.…”

“…The authors [7,8] examined the composition, the soluble elements and the solubility of the cements, but the surface state of the set cement after the elusion of elements was unknown. Therefore the authors conducted the following research on the surface state of zinc phosphate and carboxylate cements after they had been immersed in distilled water for seven days, with the aim of establishing bases for developing an insoluble cement.…”

Studies on the improvement of zinc phosphate cement (II). Synthesis of lysine derivative and determination of its structure.

“…The authors have hitherto carried out various studies [1][2][3][4][5] on dental luting cement. Especially in the previous report [5], purposing to give adhesiveness to zinc phosphate cement, the authors made L-lysine monohydrochloride reacted with phthalic anhydride to synthesize a lysine derivative to be mixed with zinc phosphate cement.…”