Evaluatıon the degree of polymerızatıon of bulk fıll composıte resıns

The purpose of this study was to determine the degree of polymerization of seven different brand bulk fill composites. Disk specimens 5 mm in diameter and 4 mm thick were prepared from 7 bulk fill composites (QuixfilTM, SonicFillTM, Tetric EvoCeram Bulk Fill, X-tra fil, SureFil® SDR® flow, Venus® Bulk Fill ve X-tra base). The specimens were cured by LED light curing unit for 20 sec. Light-activated surfaces were polished with Sof-Lex discs. Specimens were stored at 37ºC dry in the dark for 24 hours. A hardness tester was used to obtain 5 measurements of Vickers hardness number for each surface (top and bottom) of each specimen. After that specimens were stored at 37ºC dry in the dark for 7 days. Microhardness measurements were repeated for all specimens after 7 days. Mean Vickers hardness numbers of the top and bottom surfaces of each specimen were calculated. Relative hardness was calculated as the Vickers hardness number of the bottom surface divided by the Vickers hardness number of the top surface. The measurement results were evaluated statistically. Using a minimum Vickers hardness ratio of 0,8 bottom/top, SonicFillTM, X-tra fil, SureFil® SDR® flow, Venus® Bulk Fill and X-tra base achieved in degree of polymerization. The hardness value and degree of polymerization was not statistically significant at days 1 and 7.