The influence of mixing temperature and powder/liquid ratio on the film thickness of three glass-lonomer cements

Three glass-ionomer cements, mixed at room temperature and cold mixed, were evaluated for film thickness at different powder to liquid ratios. Film thickness was measured al 1,2, and 3 minutes after mixing was initiated. The relative accuracy of the manufacturer’s voiumetric dispensing systems was also measured. For two of the three cements tested, cold mixing significantly reduced film thickness at extended working times and increased powder/liquid ratios. The results suggest that the appearance of he cement surface indicates setting in advance of film thickness and that cold mixing should be routinely employed.