Calcium Hydroxide Associated With Chitosan Nanoparticles and Propolis: Effects on the Sealer‐Dentin Interface

OBJECTIVE: This study evaluated the effect of calcium hydroxide-based intracanal medication protocols on the sealer-dentin interface, considering bond strength, adhesive interface adaptation, failure pattern, and dentin gelatinolytic activity. MATERIALS AND METHODS: Fifty extracted human single-rooted teeth were biomechanically prepared and assigned to five groups (n = 10): no medication, calcium hydroxide, calcium hydroxide with chitosan nanoparticles, calcium hydroxide with propolis, and calcium hydroxide with chitosan nanoparticles and propolis. After 14 days, the medications were removed and the canals were obturated with AH Plus sealer. Bond strength was assessed by the push-out test, adhesive interface adaptation by confocal laser scanning microscopy, failure mode by stereomicroscopy, and gelatinolytic activity by in situ zymography. RESULTS: No significant differences in bond strength or adhesive interface adaptation were observed among the experimental groups (p > 0.05). Failure mode was associated with the experimental group and root third (p < 0.05), with mixed failures predominating. The combination of calcium hydroxide, chitosan nanoparticles, and propolis showed significantly lower gelatinolytic activity than the non-medicated control and calcium hydroxide alone (p < 0.05), whereas the other medicated groups did not differ from the control. CONCLUSIONS: Calcium hydroxide-based intracanal medications, alone or combined with chitosan nanoparticles and/or propolis, did not affect sealer-dentin bond strength or adhesive interface adaptation. The combination of calcium hydroxide, chitosan nanoparticles, and propolis reduced dentin gelatinolytic activity compared with the non-medicated control and calcium hydroxide alone. CLINICAL SIGNIFICANCE: The tested calcium hydroxide-based medications did not impair sealer-dentin adhesion. The association of calcium hydroxide with chitosan nanoparticles and propolis reduced dentin gelatinolytic activity without affecting immediate adhesive outcomes.