engleski

Polymerization Kinetics of Composites with Two Types of Bioactive Glass

Objectives: To investigate the effect of two types of bioactive glass (BG) on polymerization kinetics of experimental resin composites. Methods: Resin composites were based on a photo-curable Bis- GMA/TEGDMA (60:40 in wt%) resin system. The composites with a total filler load of 70 wt% were functionalized with varying amounts (5, 10, 20, and 40 wt%) of either BG 45S5 or a low-sodium fluoride-containing BG. Uncured composites were cast in Teflon molds (n= 6, diameter=6 mm, height=2 mm) on top of a diamond ATR crystal and light-cured using 1, 100 mW/cm2 for 20 s. Real- time changes in degree of conversion (DC) occurring during light-curing and 5 min post-cure were monitored at the data collection rate of 2 s- 1 using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). From the time-dependent DC curves, the first derivative was calculated to represent reaction rate. Results: At the end of the 5-min observation period, DC values for the composites functionalized with BG 45S5 ranged from 59.2– 66.5%, and were significantly reduced by increasing BG amounts. In contrast, the 5-min DC values for the low-sodium fluoride-containing BG (64.7–67.0%) were not significantly affected by BG amounts. The polymerization rate for BG 45S5 (6.3– 12.5 %/s) decreased as a function of higher BG amounts. The composites functionalized with low- sodium fluoride-containing BG had comparatively higher polymerization rates (12.7–14.3 %/s) and showed a statistically significant reduction of polymerization rate only for the highest BG amount (40 wt%). Maximum polymerization rate occurred within 0.8–1.4 s from the start of light-curing and represented a less discriminative parameter due to high data scattering. Conclusions: The 5- min DC values and polymerization rate were significantly diminished by the addition of BG 45S5, while the addition of a low-sodium fluoride- containing BG showed a minor effect on kinetic parameters.

polymerization kinetics ; experimental composites ; bioactive glass

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