Influence of Light Energy Density, Composite Type, Composite Thickness,and Postcuring Phase on Degree of Conversion of Bulk‑fill Composites

Gupta, Ravi (2018) Influence of Light Energy Density, Composite Type, Composite Thickness,and Postcuring Phase on Degree of Conversion of Bulk‑fill Composites. Contemporary Clinical Dentistry, 9. pp. 147-152. ISSN 0976-237X

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Abstract

Context: Achieving a high degree of conversion (DC) is one of the major concerns during photopolymerization of bulk‑fill composites. Aims: To evaluate the effect of light energy densities (11.2 J/cm2 and 20 J/cm2) on the DC and variation of DC in the 24‑h postcuring of four bulk‑fill composites: SDR, Venus Bulk Fill, MI FIL, and Tetric N‑Ceram Bulk Fill at simulated clinically relevant filling depths. Settings and Design: This was an in vitro comparative study.Subjects and Methods: A total of twenty samples were prepared using a teflon mold. VALO curing light was used with two light intensity modes of 1000 mW/cm2 for curing time of 20 s and 1400 mW/cm2 for curing time of 8 s. The energy density was calculated as follows: energy density (J/cm2) is the light intensity (mW/cm2) applied during a certain time (s) divided by 1000.The DC was measured at two time intervals: immediately postcure and after 24‑h storage in artificial saliva using an Fourier‑transform infrared spectroscopy equipped with attenuated total reflectance accessory. Statistical Analysis Used: ANOVA and Bonferroni test at P < 0.05. Results: High energy density (20 J/cm2) leads to higher DC. Thickness, type of composites, and postcuring phase strongly influence the DC. DC values of the top surface for all the bulk‑fill materials investigated were found significantly greater (P < 0.005) than those of their bottom surface. Among composites, SDR showed highest DC. DC strongly increased after 24‑h postcure by 32% on top surface and 76% on bottom surface. Conclusions: Energy density more than 20 J/cm2, derived by increasing curing time and low power density, helps obtain a high DC of bulk‑fill composites for adequate clinical performance.

Item Type: Article
Uncontrolled Keywords: Bulk‑fill composites; Curing; Degree of conversion; Energy density; Post; Thickness
Subjects: Dentistry > MCODS Manipal > Conservative Dentistry and Endontics
Depositing User: KMC Library
Date Deposited: 23 Aug 2018 04:33
Last Modified: 23 Aug 2018 04:33
URI: http://eprints.manipal.edu/id/eprint/151836

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