title: Time-dependent conversion of a methacrylate-based sealer polymerized with different light-curing units.
abstract: The purpose of this study was to investigate the degree of conversion of a methacrylate-based sealer (Epiphany; Pentron Clinical Technologies, Wallingford, CT) with regard to the method of photoactivation, distance from the light-curing unit (LCU), and post-curing time. Freshly mixed Epiphany sealer was dispensed into half-pipe-shaped silicone moulds (n = 48), after which the specimens were photoactivated with one of the following LCUs from the coronal aspect: (1) quartz tungsten halogen/40 seconds and (2) light-emitting diode/20 seconds. In each specimen, the degree of conversion was measured at three different locations (coronal, middle, and apical) using Fourier transform infrared spectroscopy before and after photoactivation. The amount of conversion was approximately 50% after photoactivation and improved by approximately 10% after 15 days. Conversion of Epiphany was not affected by the type of LCU (p > 0.001) or the distance from the LCU (p > 0.001) but showed a significant increase within time (p < 0.001). These results indicate incomplete polymerization of Epiphany, despite a post-curing time of as long as 2 weeks in vitro.
authors.affiliation: School of Dental Technology, Hacettepe University, Ankara, Turkey.
authors.forename: Nilufer C
authors.initials: NC
authors.lastname: Beriat
authors.forename: Atilla
authors.initials: A
authors.lastname: Ertan
authors.forename: Zafer C
authors.initials: ZC
authors.lastname: Cehreli
authors.forename: Kamran
authors.initials: K
authors.lastname: Gulsahi
mesh_terms: D055117:Curing Lights, Dental; D006219:Halogens; D006244:Hardness; D055115:Light-Curing of Dental Adhesives / Q000295:instrumentation*; D008422:Materials Testing; D044367:Phase Transition; D019279:Resin Cements / Q000528:radiation effects*; D012387:Root Canal Filling Materials / Q000528:radiation effects*; D012666:Semiconductors; D017550:Spectroscopy, Fourier Transform Infrared; D013997:Time Factors
chemical_list: D006219:Halogens; D019279:Resin Cements; D012387:Root Canal Filling Materials; C486893:epiphany sealer