Microleakage and internal voids in class II composite restorations with flowable composite linings

This study determined the influence of a flowable composite lining on margi nal microleakage and internal voids in a Class II composite restoration. Fo rty-eight extracted molars were prepared with Class II cavities and randoml y divided into four groups: Group I-Prodigy filling/ Revolution lining; Gro up IZ-Prodigy filling only; Group III-Tetric Ceram/Tetric Flow lining; Grou p IV-Tetric Ceram filling only. After thermocycling tests and dye soaking, these teeth were sectioned longitudinally. Gingival-marginal microleakage a nd internal voids in three separate portions of the restoration (Interface, Cervical and Occlusal voids) were observed with a stereomicroscope, Result s revealed no significant difference in the marginal sealing between pairs with or without the flowable composite lining. Restorations conducted with a flowable composite lining (Groups I and III) exhibited fewer total voids and fewer voids in the interface (p<0.05). However, there was no significan t correlation between the number of restoration voids and the associated mi croleakage, A flowable composite lining in a Class II resin filling could e ffectively reduce the voids in the interface and the total number of voids in the restoration, but may not necessarily improve marginal sealing.