The Effect of Powder/Liquid Ratio on Microleakage of Resin-Modified Glass-Ionomer

Introduction: resin modified glassionomer cement (rmgi) is prepared by manual mixing of powder and liquid. different mixing ratios influence on the rmgi properties. the aim was to compare the effect of different mixing ratios on the microleakage of rmgi.materials methods: in this in vitro study, 60 class v cavities (3 times;2 times;1.5 mm) with the gingival margin of 1 mm apical to the cementenamel junction were prepared on the buccal and lingual surfaces of 30 sound premolars. the teeth were randomly divided into 6 groups. group 1: the manufacturer rsquo;s recommended ratio, without conditioning; group2: the manufacturer rsquo;s recommended ratio with conditioning; group 3: 20% lower than the manufacturer rsquo;s ratio without conditioning; group4: 20% lower than the manufacturer rsquo;s ratio with conditioning; group 5: 20% higher than the manufacturer rsquo;s ratio without conditioning; group6: 20% higher than the manufacturer rsquo;s ratio with conditioning. after thermocycling, the microleakage was evaluated using silver nitrate staining. the teeth were cut into two mesial and distal halves, and the microleakage at occlusal and gingival margins was recorded based on a 0‒3 scoring system under a stereomicroscope. data were analyzed using kruskalwallis and mannwhitney tests with significance level at p<0.05.results: the maximum microleakage at gingival margins was recorded for group 4, which was significantly higher than that of group 2 and 6 (p=0.043 and p=0.043, respectively). no significant differences were observed in the microleakage between occlusal and gingival margins.conclusion: a 20% reduction in p/l ratio of rmgi increases the gingival microleakage when surface conditioning was appli.