Residual monomers released from glass-fibre-reinforced composite photopolymerised in contact with bone and blood

Abstract

The surface of the bone or contact with blood did not significantly inhibit the photoinitiated free radical polymerisation of the dimethacrylate monomer system of the FRC.

Residual monomers and degree of conversion of partially bioresorbable fiber-reinforced composite

“…These values of DC% are comparable with other studies concerning approximately the same kind of polymer matrix (commercial 75%/25% Bis-GMA/TEGDMA) [32]. However, greater values (%63%) [16,24] and also lower values [15] have been described. In general, fillers or other auxiliary substances decrease DC% [14,19] because there are some filler-resin interactions during curing.…”

“…After photo-initiated polymerization of the monomer resin, the specimens were immediately immersed in water to evaluate the quantity of leakage of the residual monomers of Bis-GMA and TEGDMA. The monomer of TEGDMA was the main residual substance released from the composites (as found also in other studies [23,24]); its quantity was almost 30 times greater than the monomer of Bis-GMA. The quantity of TEGDMA released from the specimens was slightly higher (0.6 wt.%) than that found in the same kinds of composites (0.4 wt.%) [24].…”

“…The monomer of TEGDMA was the main residual substance released from the composites (as found also in other studies [23,24]); its quantity was almost 30 times greater than the monomer of Bis-GMA. The quantity of TEGDMA released from the specimens was slightly higher (0.6 wt.%) than that found in the same kinds of composites (0.4 wt.%) [24]. When comparing the quantity of residual TEGDMA (ppm) to the other studies, our findings are lower (<200 ppm) than others (>250 ppm) for 7 daysÕ immersion [25].…”

“…This is probably caused only by the different Bis-GMA/TEGDMA ratio; in our study, the wt.% of TEGDMA was considerably lower (70/30 vs. 50/50). With regard to the amount of released Bis-GMA there was no difference in results (0.01 vs. 0.02 wt.%) [24], although Inoue and Hayashi described about five times greater amounts for released Bis-GMA from the commercial restorative composite [13]. The quantity of leached TEG-DMA and Bis-GMA measured from the weight of the initial monomer quantity was about 10 times higher than that measured from the weight of the specimen.…”

Degree of conversion and leached monomers of urethane dimethacrylate-hydroxypropyl methacrylate-based dental resin systems

“…Hence, a short chain length and low DC is often observed, leading to somewhat inferior mechanical properties (5,6). On the other side, the oxygen inhibition layer also contains unpolymerized monomers and oligomers (7), which reduce the DC values and can, therefore, be leached out.…”