Purpose: This in vitro study evaluated marginal integrity, 2-body wear, and fracture behavior of an array of bonded and nonbonded posterior restorative materials after thermomechanical loading (TML).
Materials and methods: Eighty-eight MOD cavities with one proximal box beneath the CEJ were prepared in extracted human third molars according to a well-established protocol. Direct restorations were made using the following materials: amalgam (Dispersalloy), Ketac Molar Quick, Surefil One (with or without light curing), Activa, AdheSE Universal/Heliomolar, Fuji II LC improved, Equia Forte, Scotchbond Universal/Filtek Supreme, Xeno V+/CeramX.mono+, Prime&Bond active/Spectra ST CeramX HV, Prime&Bond elect/Spectra ST CeramX HV. Before and after thermomechanical loading (2500/5000/12,500 thermocycles between 5°C and 55°C + 100,000/ 200,000/500,000 x 50 N), marginal gaps and 2-body wear depths were analyzed on epoxy resin replicas using SEM and CLSM. Fractures were observed under a light microscope (20X). Results were analyzed with Kruskal-Wallis and Mann-Whitney U-tests (p < 0.05).
Results: For marginal quality, Surefil One showed promising in vitro behavior close to that of resin composite bonded with a self-etch adhesive (p > 0.05). For wear, amalgam and resin composites with recent filler technology were still superior (p < 0.05), but Surefil One LC outperformed Activa, Ketac Molar Quick, Equia Forte Fil, and Fuji II LC (p < 0.05). When Surefil One was occlusally light cured, no fractures occured, even after 500,000 cycles of TML.
Conclusion: The novel self-adhesive posterior restorative Surefil One did not exhibit superior outcomes for all evaluated aspects. However, it showed stable fracture behavior, good marginal quality, and acceptable wear resistance in vitro.
Keywords: amalgam alternatives; resin composites; resin-modified glass-ionomer cements; self-adhesive materials.