engleski

Degree of Conversion of Experimental Composites Based on Bioactive Glass 45S5 and Bis-EMA/TEGDMA resin

Objectives: To investigate the depth-dependent degree of conversion (DC) of experimental composites based on Bis-EMA/TEGDMA 60/40 resin and bioactive glass 45S5 (BG). Materials and Methods: An experimental resin composite series was prepared with 0-40 wt% of BG and a total filler load of 70 wt%. Composite specimens (n=5 per material) were light-cured (20 s at 1000 mW/cm2) in stainless steel cylindrical split-molds and the DC was investigated by FT-Raman spectrometry immediately after curing and 24 h post-cure. The DC was evaluated as a function of layer thicknesses for up to 4 mm. Results: The highest DC (80.6-89.7% at layers up to 2 mm) was measured for the control composite containing only 70 wt% of inert fillers. The DC measured at all layer thicknesses was significantly affected by the addition of BG fillers in a dose-dependent manner. Increasing the load of BG fillers in the following steps (wt%): 0, 5, 10, 20, and 40, resulted in a significant decline of the 24-h DC (%) as follows: for 0 mm: 88.3, 89.4, 68.7, 41.5, 33.2 ; for 1 mm: 89.7, 81.5, 50.2, 28.1, 19.9 ; for 2 mm 80.6, 52.3, 26.5, 7.3, 6.1 ; and for 3 mm 59.3, 28.5, 12.7, 3.8, 3.5. For layer thickness of 4 mm, the DC was clinically unacceptable for all materials. The extent of the post-cure reaction was highly variable among the materials and ranged from 2.8 to 20.5%. The depth-dependent DC decline was more severe in composites with higher amounts of BG. Conclusions: The addition of BG fillers into a Bis-EMA/TEGDMA resin had a strong negative effect on the curing potential of experimental composites. The BG amounts of 20 wt% or more resulted in clinically unacceptable DC values.

Degree of Conversion ; Remineralizing Resin Composites ; Bioactive Glass 45S5 ; Raman Spectroscopy

nije evidentirano