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Introduction: This study is a pilot investigation of weight changes during water immersion of experimental composites functionalized with two types of bioactive glass (BG). Materials and methods: Experimental resin composites were prepared using a Bis-GMA/TEGDMA resin system (60:40 by weight). The photo-curable composites were functionalized with 0, 5, 10, 20, and 40 wt% of either BG 45S5 or a low-sodium fluoride- containing BG. The total filler load for all composites was 70 wt%. Three commercial restorative materials (giomer, glass ionomer, and alkasite) were used as references. According to a modified ISO 4049 gravimetric method, cured material specimens were immersed in distilled water and their weight changes were measured after 1, 3, 7, 14, 21, and 28 days. Results: Non- monotonous time-dependence of weight changes characterized by an initial increase followed by a peak and a subsequent decrease were identified for the experimental composites with the highest amounts of BG (40 wt%). At the end of the observation period (28 days), relative weight changes were as follows: 2.6% for the control composite containing only inert fillers, 2.0–3.8% for the experimental composites functionalized with BG 45S5, and 0.9–1.7% for the experimental composites with low-sodium fluoride-containing BG. The highest weight change was identified for the glass ionomer (6.1%), while weight changes for the giomer and the alkasite amounted to 1.0% and 0.4%, respectively. Conclusions: Different patterns of weight gain and loss were identified by subsequently weighing the specimens of water- immersed composite materials, indicating that uptake of water and release of material constituents occurred simultaneously. This study was supported by Croatian Science Foundation, project IP-2019-04-6183. |
