Bonding behavior of restorative materials in primary teeth submitted to erosive challenge − evidence from an in vitro study

Purpose: To evaluate bond stability of restorative materials to eroded primary teeth after aging. Methods: 120 primary molars were assigned into 12 groups, in according to substrate – enamel or dentin, precondition of substrate – sound or eroded, and restorative material – resin composite/adhesive system-RC, high-viscosity glass ionomer cement–HVGIC or resin-modified GIC–RMGIC. Eroded groups were subjected to erosive challenge prior to bonding procedures. Polyethylene tubes were placed on flat surfaces of substrates and filled up with one of materials. After 24 h, half of the specimens were submitted to microshear bond strength (BS) test, and the other half after 12 months. Results: Generally, sound substrates resulted in higher BS values than eroded ones, with exception of HVGIC that obtained similar performance in both substrates. Furthermore, the storage period negatively influenced BS values for RC groups on dentin assessment. The other groups did not show reduction in BS values after 12 months. RC showed better bonding performance than others materials. Conclusion: Previously eroded substrates result in the worst performance of RC and RMGIC. Moreover, the water storage affects the bonding stability of RC to dentin. On the other hand, HVGIC is not affected by precondition of substrate neither storage.