The effect of weight loss of liquid on the diametral tensile strengths of various kinds of luting cements.

The role of water evaporation from the liquids of the cements were tested, and the effect of this loss on their strength was evaluated for 0, 10, 20 and 30 minute, intervals. After 30 minutes the evaporation of liquid from the cements was so high that they lost their luting consistency. The data suggests that the highest weight loss was with polycarboxylate cement liquids, with glass-ionomer and zinc phosphate cement liquids following respectively. However, when diametral tensile strength test values were evaluated it was determined that glass-ionomer exhibited the highest resistance to fracturing and zinc phosphate the lowest. Upon examination of samples which were fractured, while polycarboxylate and glass-ionomer cracked and split into large fragments, zinc phosphate cements fractured into a multitude of small pieces. On the basis of this study, it appears that the manufacturers' recommendations about the powder-to-liquid ratio and the mixing procedures is confirmed particularly and should be adhered to for optimal results.