The effect of thermocycling on microleakage analysis of bulk filled base composite in comparison to incrementally placed nanohybrid composite in class II MOD restorations (An in vitro study)


Background: The study aim was to evaluate thermocycling effect on microleakage of occlusal and cervical marginsof MOD cavity filled with bulk filled composites in comparison to incrementally placed nanohybrid composite and toevaluate the difference in microleakage between enamel and dentin margins for the three materials groups.Materials and method: Forty eight maxillary first premolars were prepared with MOD cavities. Samples were dividedinto three groups of sixteen teeth according to material used: Grandio: Grandio. SDR: SDR +Grandio. X-tra: X-tra base+ Grandio. Each group was subdivided into two according to be thermocycled or not. After 24 hrs immersion in 2%methylene blue, samples weresectioned and microleakage was estimated.Results: Thermocycling significantly increased microleakage at occlusal margin in Grandio group compared to othergroups. SDR composite use before and after thermocycling significantly reduced microleakage at occlusal andcervical enamel margins compared to other groups. Grandio group had non significant difference to X-tra group inmicroleakage before thermocycling at occlusal and cervical enamel margins while it had a significant increase afterthermocycling. No material had significantly reduced dentin margin microleakage before or after thermocycling.Only SDR group before thermocycling, significantly reduced microleakage in enamel margin compared to dentinmargin.Conclusion: Thermocycling did not increase microleakage in all the groups except for Grandio group in occlusalmargin. SDR group showed reduced microleakage in occlusal and enamel margins in comparison to othergroups.None of the materials reduced microleakage in dentin margin