Nanoleakage related to bond strength in RM-GIC and adhesive restorations

Abstract

This was to investigate the nanoleakage of Resin Modified Glass Ionomer Cement (RMGIC) and composite resin (CR) restorations in sound and caries-affected primary dentine, submitted to load cycling and cariogenic challenge in vitro. Occlusal cavities were prepared in 60 sound exfoliated primary second molars and 30 specimens were subjected to chemical induction of artificial caries lesions and the others were restored without caries induction. All prepared teeth were divided into 2 groups according to restorative materials. From each dentine condition 5 restored teeth and restorative material were subjected to microtensile bond strength and nanoleakage tests immediately or after load-cycling or submitted to the pH-cycling procedure before testing. The adhesive presented bigger areas of silver leakage at the interfaces on caries-affected dentine (2.46±0.47)mm2 than sound dentine (0.90±0.19)mm2. RMGIC nanoleakage was not influenced by the sound (1.75±0.11)mm2 or caries-affected (2.08±0.39) condition of the substrate. A significant moderate inverse correlation was revealed between the bond strength and silver leakage area at the interface, (r= -0.55, p<0.001). Nanoleakage is greater in caries-affected primary teeth dentine than sound dentine in adhesive restorations although at the interfaces of RMGIC does not differ. As nanoleakage increases, bond strength decreases significantly.