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OBJECTIVES The aim of this study was to formulate and to evaluate the immediate and long-term physical, chemical and antibacterial properties of an experimental adhesive resin with chitosan or triclosan-loaded chitosan. MATERIALS AND METHODS Chitosan, triclosan and triclosan-loaded chitosan were evaluated for scanning electron microscopy (SEM) and micro-Raman spectroscopy. An experimental adhesive resin was formulated with methacrylate monomers and photoinitiators. Chitosan or triclosan-loaded chitosan were added at 2 (GQ2% and GQT2%) or 5 (GQ5% and GQT5%) wt.% in the base resin. The base resin was used as control (GCTRL). The adhesives were evaluated for degree of conversion (DC), Knoop hardness (KHN), softening in solvent (ΔKHN), immediate and long-term microtensile bond-strength (μ-TBS) and antibacterial activity. RESULTS SEM indicated triclosan sticks and chitosan porosity. Triclosan-loaded chitosan presented structures on chitosan. Micro-Raman indicated no chemical interaction between chitosan and triclosan. There was no difference among groups for DC (p > 0.05). Initial KHN ranged from 17.36 (±1.56) to 20.38 (±1.72), with higher value for GQT5% compared to GCTRL (p < 0.05). GCTRL presented the lowest ΔKHN% (p < 0.05). There were no differences in the immediate or long-term μ-TBS (p > 0.05). GCTRL and GQ2% decreased the μ-TBS after storage (p < 0.05). Chitosan groups showed higher biofilm formation (p < 0.05). Triclosan-loaded chitosan groups presented lower biofilm formation (p < 0.05). There was no activity against planktonic bacteria regardless the time of evaluation (p > 0.05). CONCLUSION Triclosan-loaded chitosan at 5 wt.% addition in an experimental adhesive resin showed reliable properties, with the highest antibacterial activity immediately and after six months, and induced dentin/adhesive interface stability over time. CLINICAL SIGNIFICANCE Triclosan-loaded chitosan groups showed antibacterial activity immediately and over time and induced dentin/adhesive interface stability, may positively affecting long-lasting marginal sealing.