The Influence of a Translucent Fiberglass Post on the Polymerization of Dual Cure Resin Cement Analyzed by Electron Paramagnetic Resonance

Abstract

Electron Paramagnetic Resonance (EPR) was used as an alternative method to study the conversion degree of dual cure resin cement and verify the influence of prefabricated translucent fiberglass post on the dual cure resin cement polymerization at different restoration points. The post cementation of White Post DC (FGM, Joinville, SC, Brasil) was simulated using the dual cured resin cement Allcem (FGM, Joinville, SC, Brasil) in three different protocols: cement irradiated for 40 s; no light irradiation and cement irradiated with sealed cementation line. 2mm samples were obtained from three post sections and EPR spectra were obtained 10 minutes and 24 hours after mixing the base paste and catalyst of the cement. Results shows that the light curing protocol influenced the concentration of free radicals up to 8mm of the restoration, and the capacity of light transmission of the post was significant for the first 8mm of restoration and is non-existent in the deepest points of a simulated root canal. The cure in the apical part of restoration is exclusively chemical.

Influence of Geometrical Configuration of a Translucent Fiberglass Post on the Polymerization of a Dual Cure Resin Cement Analyzed by EPR Spectroscopy

“…Proportionality was observed between the FR concentration and quality of the resinous material, indicating that EPR spectroscopy is an important tool for understanding these dental restorative materials [22]. These data are in accordance with Salomão et al [24]. In that case, authors studied the influence of the irradiation protocol in the depth of cure and observed that the irradiation protocol influences only in the first 8 mm of the 20-mm long double-shaped translucent fiberglass post.…”

Peroxide-Free and Amine-Free Redox Free Radical Polymerization: Metal Acetylacetonates/Stable Carbonyl Compounds for Highly Efficient Synthesis of Composites

“…First, we focused on Mn­(acac) 3 /Dket1 interaction. Interestingly, in Figure A, the final polymer cured using Mn­(acac) 3 /Dket1 (curve 1) or BPO/4- N , N -TMA (curve 2) shows radicals trapped in the polymer matrix at 3500 ± 50 G (see also Figure B), in line with the literature. − On the contrary, the signal of the polymer is clearly showing six bands typical of Mn­(II) when the Mn­(acac) 3 /Dket1 initiating system is used (Figure A, curve 1); we can therefore clearly expect that some Mn­(II) are trapped in the polymer after reaction. In other words, it strongly suggests the reduction of Mn­(III) to Mn­(II) by Dket1.…”

Semi-interpenetrating network composites reinforced with Kevlar fibers for dental post fabrication

“…Nevertheless, KF posts are less translucent than everStick ® and other commercial glass fiber posts. It has been suggested that the ability of light to be transmitted along translucent posts could increase the conversion degree of light-cured resin cements with a consequent improvement of their mechanical properties, however, the efficiency of this propagation, especially in the deeper regions has still to be investigated 33) . A previous report showed no significant difference in root dentine bond strength values between translucent and opaque fiber posts 34) .…”