Bonding of Calcium Silicate-based Restorative Material to Dentine

Abstract

Objectives: To evaluate the micromorphology of calcium silicate-based restorative material/dentine and CPP-ACP modified glass ionomer/dentine interfaces. Also, this study was designed to investigate the effect dentine-surface treatment using poly acrylic acid (conditioner) on the bonding of calcium silicate-based restorative material to dentine. Methods: Eighty sound human molars were used in this study after total removal of the enamel. Exposed dentine samples were randomly divided into two groups according to type of restorative material used; calcium silicate-based (Biodentine, Septodont, France) or CPP-ACP modified glass ionomer (Fuji VII-EP, GC Corporation, Tokyo, Japan). Each group was further divided into two sub-groups according to the dentine surface treatment method; the dentine in control group was left without treatment, while the dentine surface in test groups was conditioned with poly acrylic acid (PAA) for 10s prior to the application of restorative materials. In each subgroup, ten bonded specimens were utilized in micromorphological analysis of restorative material/dentine interface using a double-labeling confocal laser scanning microscopy (CLSM) technique. While the remaining specimens were observed under scanning electron microscopy (SEM) then subjected to EDX elemental analysis. Results: CLSM micrographs showed that the mineral rich zones (MRZ) were obvious in the non-conditioned Biodentine groups, in comparison with the conditioned corresponding groups. The ion-exchange zone was distinct in the non-conditioned Biodentine ,as well as, the conditioned CPP/ACP -modified GIC groups. In the non-conditioned Biodentine groups, a ‘unique’ crystal formation was clearly observed on/beneath the hybrid layer. These findings were confirmed by EDX-mapping outcome. Conclusions: Calcium silicate-based restorative material showed a great potential for chemical bonding to dentine. The outcome of this study revealed that that application of Calcium silicate-based restorative material (Biodentine) does not require any dentine surface treatment prior to its application.