Objectives The aim of this study was to determine and correlate the degree of conversion (DC) with Vickers hardness (VH) and translucency parameter (TP) with the depth of cure (DoC) of five bulk-fill composites. Materials and methods Six specimens per group, consisting of Tetric EvoCeram Bulk Fill (BTEC Bulk,^ Ivoclar Vivadent), SonicFill (Kerr), SDR Smart Dentin Replacement (BSDR,^ Dentsply), Xenius base (BXenius,^ StickTech; commercialized as EverX Posterior, GC), Filtek Bulk Fill flowable (BFiltek Bulk,^ 3M ESPE), and Tetric EvoCeram (BTEC,^ control), were prepared for DC and VH: two 2-mm-thick layers, each light-cured for 10 s; one 4-mm bulk-fill, lightcured for 10 or 20 s; and one 6-mm bulk-fill, cured for 20 s. DC was measured using a Fourier-transform infrared spectrometer, VH using a Vi ckers hardness tester. DoC and TP were measured using an acetone-shaking test and a spectrophotometer, respectively. Data were analyzed using ANOVA and Pearson’s correlation (α = 0.05). Results DC and VH ranged between 40–70 % and 30– 80 VHN, respectively. TEC Bulk, Xenius, and SonicFill, bulk-filled as 4-mm-thick specimens, showed bottom-to-top hardness ratios above 80 % after 20 s curing. A positive linear correlation was found for bottom DC and VH. An average DC ratio of 0.9 corresponded to a bottom-to-top VH ratio of 0.8. Conclusions Sculptable bulk-fills require 20 s, whereas 10 s curing time was sufficient for flowable bulk-fills using a highintensity LED unit. Clinical relevance Clinicians should be aware that longer curing times may be required for sculptable than flowable bulkfill composites in order to achieve optimal curing characteristics.
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