Microleakage and Marginal Integrity of Surface-Coated and Laser-Pretreated Class V Composite Restorations in Primary Teeth

Introduction: Despite the advanced formulations of resin composites, microleakage is still among the commonest causes of clinical failure of these restorations. We evaluated the effect of surface coating and laser pretreatment on the microleakage of Class V resin composite restorations in primary teeth. Methods: Sixty extracted primary molar teeth having intact lingual or facial surfaces were randomly allocated into the control, G-Coat Plus surface coating, and erbium-doped yttrium aluminum garnet (Er:YAG) laser pretreatment groups. Class V cavities were provided with the coronal and gingival margins in the dentin and enamel, respectively. Restoration of the cavities was done with Z250 resin composite and they were thermocycled, followed by immersing in 2% basic Fuchsin dye for 24 hrs. Samples underwent sectioning occlusogingivally and the microleakage was assessed under a stereomicroscope (40 x ). Statistical analysis was done via SPSS and Kruskal-Wallis test (alpha= 0.05). Results: The control and G-Coat plus groups were significantly different regarding the microleakage (P < 0.001), and G-Coat Plus and laser pretreatment groups (P < 0.001) at both gingival and occlusal margins. However, it showed no significant difference between the laser and the control group on the enamel (P = 0.063) and dentin margins (P = 0.757). Microleakage at the gingival margins was significantly greater compared to the occlusal margins in the control and laser groups (P< 0.001), but not in the G-Coat Plus group (P= 0.051). Conclusion: G-Coat plus coating significantly reduced microleakage at dentin and enamel margins of Class V composite restorations in primary teeth, in comparison with other groups of the study. Also, dentin margins showed more significant amounts of microleakage versus enamel margins in all groups, except for the G-Coat Plus group.