Bioactive glasses are surface-active and able to induce remineralization of dentin. Two resin-modified glass-ionomer cements (RMGICs) doped with bioactive glass (Biosilicate((R))) were used as restorative materials in dentin. Experimental powders were made by incorporating 2, 5, and 10wt% of Biosilicate((R)) in Vitremer((R)) (VT) and Fuji II LC (R) (FL) powders. Commercial FL and VT were used as control materials. Six cylinders of each material were tested for failure in compression (1.0mm/min), after 24h storage in distilled water at 37 degrees C. For microtensile bond strength (MTBS) test, cavity preparations were performed on 30 noncarious human molars and restored with the tested materials. Teeth were stored in water (37 degrees C) for 24h or 7 days, sectioned into beams and tested for failure in tension (0.5mm/min). Data were analyzed by analysis of variance and multiple-comparison tests (p<0.05). Analysis of debonded specimens was performed by scanning electron microscopy. Only incorporation of 2wt% of Biosilicate((R)) did not decrease compressive strength of the RMGICs. Two weight percent of Biosilicate((R)) into RMGICs produced an increase in MTBS after 24h for FL and after 24h and 7 days for VT. Two weight percent of Biosilicate((R)) particles into RMGICs did not affect compressive strength and improved MTBS to dentin.