The effect of bioactive glass particle size on viscosity, stickiness and packability of resin composites

This study investigated the impact of particle size variation in un-silanized bioactive glass 45S5 (BAG) on the viscosity, stickiness and packability of experimental resin composites, while altering the ratio of 45S5 to inert glass. A series of 25 groups experimental resin composites with a constant total filler loading (65 vol%) were formulated. Filler system contains silanized barium borosilicate (BB, D50 [µm]: 0.7) and un-silanized BAG (45S5). Different ratios of BB and 45S5 were achieved by substituting 65 vol% BB with 0, 5, 10, 15, 20, 25 or 30 vol% of 45S5 (D50 [µm]: 7.0, 10.6, 17.4 and 43.6). The morphology of filler particles and formulated experimental resin composites was examined using a scanning electron microscope (SEM). Viscosity measurements were conducted on both experimental and commercial resin composites measured using an AR-G2 rheometer. A texture analyser instrument was used to measure the stickiness and packability of resin composites. Two commercial resin composites served as control groups for comparison. Statistical analysis, including one-way ANOVA tests, Tukey post-hoc tests (p < 0.05), and Kruskal-Wallis Tests (p < 0.05) for homogeneity of variables, was performed using SPSS software. Results indicated that filler loading and particle size of 45S5 significantly influenced the viscosity, stickiness, and packability of resin composites. Resin composites containing smaller 45S5 particles at lower ratios exhibited characteristics akin to packable resin composites, whereas those with larger 45S5 particles tended to resemble commercial flowable resin composites, contingent upon the particle size and ratio of 45S5.