In Vitro Comparison of Microleakage of Two Nanohybrid Flowable Composites and RMGI in Class V Restorations in Primary Molars

Introduction: Composite resins undergo microleakage due to polymerization shrinkage particularly when located in enamel free margins. The purpose of this study was to assess and compare the  microleakage of two nanohybrid  flowable composites and resin modified glass ionomer in class V restorations of primary mandibular second  molars.  Materials and Methods: This in vitro, experimental study was conducted on 30 primary mandibular second  molars which were randomly divided into three groups. Standard class V cavities were prepared and restored with Grandio flow in Group A, G-aenial universal flow in Group B and RMGI in Group C. The restored teeth underwent 3000 thermal cycles between 5–55°C and then immersed in1M silver nitrate solution for 24 hours. The samples were sectioned buccolingually and degree of dye penetration was evaluated by stereomicroscope at ×10 magnification. Mann-Whitney U test and Paired T-test were used to analyze the data.  Results: In occlusal margin, there was no significant difference between three groups but at gingival margin, Grandio flow demonstrated significantly lower microleakage than G-aenial universal flow (P=0.002). There was not significant difference between Grandio flow and RMGI and also between RMGI and G-aenial universal flow (P>0.05). Conclusion: Grandio flow is effective for decreasing the microleakage on enamel free margins.