Effect of Dentine Surface Treatment on Bonding of Bioactive RMGI-based Restorative Material to Dentine

Objectives: To evaluate the effect of different dentine surface treatment methods on bonding of bioactive RMGI-based restorative material to dentine
Methods: A total number of 25 caries-free human permanent molars were used as the bonding substrate. The occlusal enamel was removed using a low-speed diamond saw (Isomet, Buehler, USA). The selected molars were divided into 5 groups (n=5) according to the dentine surface treatment method used; saline (control), 10% citric acid (10s),17% EDTA (10s), 37% Phosphoric acid (10s) or polyacrylic acid (10s). Then, restorative material was placed to cover the exposed dentine surface following the manufacturer instructions. The hybrid/hybrid-like layer was observed using environmental field emission scanning electron microscopy E-FESEM operated in secondary electron/ back -scattered detection modes. Furthermore, the tooth/restoration interface was subjected to an elemental analysis using Energy Dispersive X-ray (EDX) and EDX mapping.
Results: The micromorphological analysis of tooth/restoration interface showed that bioactive RMGI-based restorative material (Activa) exhibited good hybridization with dentine following surface treatment with 10% citric acid, as well as, saline. The outcome of elemental analysis showed that 10% citric acid did not adversely affect the calcium content of dentine in comparison with surface treatment using phosphoric acid.
Conclusions: Water plays a great role in bonding of bioactive restorative materials to dentine. These materials can directly bond to dentine after rinsing of the surface with saline. Although, bioactive RMGI restorative material manufacturer recommends conditioning the dentine with phosphoric acid prior to insertion of materials, it is highly advisable and more conservative to use 10% citric acid.