Time-depending solubility of different fixed prosthetic permanent luting cements

Abstract

The solubility of dental cements is important property due to their prolonged exposure to oral fluids. Тhe recommended standard is 0.2% mass loss for 24 hours. The aim of the study is to measure and compare the values of the solubility in different types of permanent cements as a function of time of exposure to the solvent. Four types of cements were selected: zinc phosphate (ZP), glass-ionomer (GI), resin-modified glass-ionomer (RG) and polycarboxylate (PC) cement. Totally 120 samples, equally divided in 4 series, were fabricated according to the experimental method recommended for in vitro laboratory measuring of the mass loss of the cement due to solubility. Distilled water was used as a solvent. The measuring of every sample weight was performed before and after immersing in solvent for 1, 7, 14 and 21 days and mass loss was calculated as a percent of initial weight of the sample. According to the results, the mass loss of selected cements after immersion in distilled water for the initial 24hours period was 0.28% for ZP cement, 0.32% for RG, 0.51% for PC and 0.57% for GI cement. After this period, the mass loss decreased and was minimal at the end of the third week. The precise evaluation of this basic characteristic is necessary for predicting clinical behavior of the permanent cement and the exact cement selection in every single case. Keywords: permanent cementation, dental cement, solubility, dissolution