The aim of this study was to asses in vitro the potential of methacrylate-based adhesive resins containing niobium pentoxide (Nb 2 O 5 ) for stimulating phosphate deposition. Adhesive resins were obtained by mixing 50 wt% BisGMA, 25 wt% TEGDMA and 25 wt% HEMA, and Nb 2 O 5 was added on 2.5 or 5 wt% to the resin. Discs 6.5 mm in diameter and 1.5 mm in height of the resin without Nb 2 O 5 and of the resins presenting the oxide were obtained by inserting the resin into a silicon matrix, followed by photo activation. Discs were immersed in simulated body fluid at 36°C for 1, 7 and 28 days, and then their surfaces were examined by Raman spectroscopy. Changes of intensity of the 962 cm −1 peak, related to phosphate bond, over the samples’ surfaces were used to assess the potential of adhesive resins to stimulate phosphate deposition. Experimental groups containing 2.5 and 5 wt% niobium pentoxide presented a phosphate-rich layer deposition over their surfaces after 7 and 28 days of SBF immersion, and this deposition increased over time. Incorporation of 2.5 or 5 wt% niobium pentoxide provides the potential to promote phosphate deposition on methacrylate-based adhesive resins.