This study's aim was to assess whether the Renewal MI composite can self-etch enamel, seal sound cavities, and stabilize demineralized dentine. Etching was assessed using scanning electron microscopy (SEM). Cavity sealing was quantified using the ISO-11405 dye microleakage test. Demineralized dentine stabilization was evaluated by visualizing resin tag formation, enzyme activity and mineral precipitation at the adhesion interface. Renewal MI provided a mild etching of sound enamel in comparison with 37% phosphoric acid. It provided a comparable seal of sound cavities to Z250/Scotchbond Universal adhesive and a superior seal to Activa, Fuji IX and Fuji II LC. With demineralized dentine, Renewal MI formed 300-400 µm resin tags covering 63% of the adhesion interface compared with 55 and 39% for Z250/Scotchbond and Activa. Fuji IX and Fuji II LC formed no resin tags. A higher tag percentage correlated with lower surface enzyme activity. Unlike Activa and Fuji II LC, Renewal MI promoted mineral precipitation from simulated body fluid, occluding adjacent dentinal tubules within 6 months. These novel etching and sealing properties may facilitate Renewal MI's application in minimally invasive dentistry.
Keywords: dental composite; dentine sealing; enzymatic degradation; microleakage; minimally invasive dentistry; remineralization.