Evaluation of Degree of Conversion, Flexural Strength, and Microhardness of a Novel Flowable Resin Composite

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Aim: This in vitro study aimed to compare the degree of conversion, flexural strength, and microhardness of a recently developed flowable resin composite in clinical use and to evaluate polymerization and mechanical characteristics. Materials & Methods: ZENIFLOW (65% filler ratio by volume) and Dynamic flow (60% filler ratio by volume) composites (President, Germany) were subjected to a three-point bending test (n=10) to determine flexural strength (FS) and flexural modulus (FM); Vickers micro-hardness (VHN) (n=5) and hardness-ratio (HR) were determined with a microhardness tester from bottom/top surfaces after 15-days of storage in distilled water at 37ºC. The degree of conversion (DC) was assessed by using Fourier Transform Infrared Spectroscopy (FTIR) (n=5). All samples were polymerized with a polywave LED curing unit with 1000 mW/cm2 (Valo Cordless, Ultradent) for 20 s. Polishing procedures were performed with 4-step polishing discs (BISCO, USA). The fractured surfaces formed after flexural strength assessment were examined with a stereomicroscope (Leica MZ7.5, Germany) and a Scanning Electron Microscope (SEM) (Zeiss EVO MA10, Germany). Independent samples t-test was used to compare the values according to the groups. The significance level was set at p