Interfacial fracture toughness between resin-modified glass ionomer and dentin using three different surface treatments

Objectives To identify the long-term dentin–resin modified glass ionomer cement (RMGIC) interfacial fracture toughness (FT) using three different dentin surface treatments prior to RMGIC placement. Fuji II LC (GC America) was bonded to dentin using cavity conditioner (CC), Scotchbond Multipurpose (3M ESPE) complete system (SS), or Scotchbond etching and priming without adhesive (SP). Twenty-four teeth were used for each of the three groups. Methods Two samples were obtained from each tooth and they were stored in artificial saliva (AS) or oil for 1- or 24-weeks before determining interfacial FT. The results were fit to Weibull distributions with log-rank and Wilcoxon tests for comparison of failure curves over time for each experimental condition. Statistical analysis was performed at a 0.05 level of significance. Results FT values in artificial saliva were as follows: 1 week SS=SP>CC, 6 months SS>SP=CC; in oil SS=SP=CC for both storage times. A significant decline in FT occurred between 1- and 24-week storage for SS and SP. Storage in oil, on the other hand tended to increase FT values for all groups. Significance These observations support findings of hydrolytic degradation in adhesive resin-based surface treatments.