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Raman Spectroscopic Assessment of Degree of Conversion of Bulk-Fill Resin Composites – Changes at 24 Hours Post Cure

2014; Indiana University School of Dentistry; Volume: 40; Issue: 3 Linguagem: Inglês

10.2341/14-091-l

1559-2863

Matej Par, Ozren Gamulin, Danijela Marović, Eva Klarić, Zrinka Tarle,

Dental Implant Techniques and Outcomes

The aim of this study was to determine degree of conversion (DC) of solid and flowable bulk-fill composites immediately and after 24 hours and investigate the variations of DC at surface and depths up to 4 mm.Eight bulk-fill composites (Tetric EvoCeram Bulk Fill [shades IVA and IVB], Quixfil, X-tra fil, Venus Bulk Fill, X-tra Base, SDR, Filtek Bulk Fill) were investigated, and two conventional composites (GrandioSO, X-Flow) were used as controls. The samples (n = 5) were cured for 20 seconds with irradiance of 1090 mW/cm(2). Raman spectroscopic measurements were made immediately after curing on sample surfaces and after 24 hours of dark storage at surface and at incremental depths up to 4 mm. Mean DC values were compared using repeated measures analysis of variance (ANOVA) and t-test for dependent samples.Surface DC values immediately after curing ranged from 59.1%-71.8%, while the 24-hour postcure values ranged from 71.3%-86.1%. A significant increase of DC was observed 24 hours post cure for all bulk-fill composites, which amounted from 11.3% to 16.9%. Decrease of DC through depths up to 4 mm varied widely among bulk-fill composites and ranged from 2.9% to 19.7%.All bulk-fill composites presented a considerable 24-hour postcure DC increase and clinically acceptable DC at depths up to 4 mm. Conventional control composites were sufficiently cured only up to 2 mm, despite significant postcure polymerization.