The effect of Bioglass addition on mechanical and physical properties of photoactive UDMA-TEGDMA resin composites Laura Nicolae, William Palin, Richard Shelton, Paul Cooper Aim: To determine the effect of Bioglass incorporation on the polymerisation rate (Rp), degree of conversion (DC), flexural strength and modulus (FS/FM) of light-curable filled resin composites (FRCs). Methods: Experimental photoactive resins containing various UDMA-TEGDMAratios and filled with non-silanised irregular or spherical 45S5-Bioglass (50μm; 5-40mass%) and/or silanised silicate glass filler particulates (0.7μm; 50-70mass%) weretested. Rp and DC wereanalysed by real-time near-infrared spectroscopy. FS/FM of resins and FRCs were determined using three-point flexural strength tests. Results: Addition of up to 20mass%45S5-Bioglass filler significantly increased DC and FS(p<0.05), although >20mass% had deleterious effects on mechanical properties. The addition of spherical Bioglass particles resulted in an increased DC compared with that of irregular filler morphology although no significant differences mechanical properties were observed (p>0.05). Conclusion: Addition of 45S5-Bioglass with specific filler content, size and morphology resulted in enhanced mechanical and physical properties compared with conventional silicate glass FRCs.