Incorporation of chitosan into a universal adhesive system: Physicochemical characteristics, gelatinolytic activity, bond strength and interface micromorphology analyses

ABSTRACT This study evaluated the physicochemical characteristics (particle size, zeta potential and polydispersity index) of a universal adhesive system (Scotchbond Universal/3M ESPE) containing 0.5% chitosan (Ch), used as a self-etching (SE) or a total-etching (TE) strategy, and the effects of this chitosan-incorporated adhesive on microtensile bond strength stability to dentin, dentin-restoration interface, and gelatinolytic activity by in situ zymography. Dentin surfaces received treatments applying adhesive systems with or without Ch, and were used with an SE or a TE strategy. Composite resin blocks were built, and sticks were obtained and separated for microtensile bond strength tests (n=10). Assessments were made after 24-hour and 6-month storage, and the dentin/resin interface was evaluated by scanning electron microscopy (SEM) and zymography analyses (n=4). Particle size and polydispersity index increased significantly, whereas zeta potential increased and decreased significantly over time. Microtensile bond strength for the SE (without Ch) and TE (with Ch) strategies decreased significantly after 6 months (p