Effect of storage time and composite thickness on Degree of Conversion of Bulk-fill and universal composites using FTIR method

Abstract

Objective: Degree of Conversion (DC) of Resin-Based composites (RBCs) is a concern and is affected by different factors. This study was conducted to evaluate the effect of different thicknesses and storage times on DC of bulk-fill and universal RBCs using the FTIR method. Material and methods: For each of dental composite (Tetric N- Ceram Bulk Fill and Tetric N Ceram), 28 samples were prepared (14 samples with 2 mm height and 14 samples with 4 mm height). One and seven days (1d and 7d) after storage in an incubator at 37 ˚C, DC was measured and recorded using a FTIR device. Data were analyzed using t-test and Three-Way ANOVA and Tukey Post-Hoc Test. P < 0.05 was considered statistically significant. Results: DC of Bulk-fill composite is greater than universal composite. DC at 2 mm thickness is more than 4 mm. Unlike universal composite, 7d DC of Bulk-fill composite is greater than 1d. Of course, none of these differences are statistically significant (P-value > 0.05). Conclusions: Considering the limitation of this study, since no difference was found between DC of 1d and 7d, 1d DC is sufficient for clinical procedures, such as polishing, and the laboratory tests.KEYWORDSBulk-fill composites; Degree of Conversion; FTIR.

Influence of Filler Particle Sizes on the Physical Properties of Bulk-Fill Composites Compared to Conventional Composites

“…One strategy for doing this is cutting down on the amount of filler used. When the filler particles' dimensions are increased, the filler-matrix interface is reduced, reducing the scattering of light at the interface and allowing greater penetration of light into the material [ 20 , 21 ]. The change in the distribution and size of these filler particles could be the reason for the inferior performance of bulk fill composite in comparison to nanocomposite which has densely packed nanofillers.…”

Impact of photoinitiator quality on chemical-mechanical properties of dental adhesives under different light intensities

“…The photopolymerization of the experimental adhesive models was monitored in situ with an infrared spectrometer (FT-IR, PerkinElmer, Waltham, MA, EUA) with a resolution of 4cm -1 in the attenuated total reflection (ATR) mode and a transmission range of 650 cm -1 to 4000 cm -1 [7]. The technique consisted of collecting the reflected radiation from the interface between the adhesive and the crystal (ATR), providing evidence for the transformation of carbon double bonds (C=C) in the intensity range of 1638 cm -1 and of single bonds (C-C) in the 1608 cm -1 range [4,16].…”

“…The decrease in band ratio profile for intensity at 1638 cm -1 to that at 1608 cm -1 was monitored continuously during polymerization [16][17][18]. The degree of conversion (DC) was determined using the following formula, which was based on the intensity band ratios before and after lightpolymerization [10,16]:…”