The aim of this study was to investigate leachable components (monomers) in high and low viscosity dental bulk-fill resin composites and conventional resin composite materials after polymerization. ...Six bulk-fill and six conventional dental resin composite materials were used in this study. The samples of each material (three sets of triplicates) were cured for 20 s with irradiance of 1200 mW/cm
with a LED curing unit and immersed in a 75% ethanol solution at 37 °C. The eluates from each triplicate set were analyzed after 24 h, 7 days or 28 days using liquid chromatography coupled with triple quadrupole tandem mass spectrometry (LC-MS/MS). Detectable amounts of 2-Hydroxyethyl methacrylate (HEMA) were found in both Gradia materials and the amount observed across different time points was statistically different (
˂ 0.05), with the amount in solution increasing for Gradia and decreasing for Gradia Direct flo. Bisphenol A diglycidildimethacrylate (BIS GMA) was found in Filtek and Tetric materials. Triethylene glycol dimethacrylate (TEGDMA) was detected in all materials. On the other hand, there were no statistically significant differences in the amounts of TEGDMA detected across different time points in either of the tested materials. Monomers HEMA, TEGDMA, 4-dimethylaminobenzoic acid ethyl ester (DMA BEE) and BIS GMA in bulk-fill and conventional composites (high and low viscosity) can be eluted after polymerization. The good selection of composite material and proper handling, the following of the manufacturer's instructions for polymerization and the use of finishing and polishing procedures may reduce the elution of the unpolymerized monomers> responsible for the possible allergic and genotoxic potential of dental resin composites.
To investigate the long-term development of the post-cure degree of conversion (DC) for two flowable bulk-fill composites.
Tetric EvoFlow Bulk Fill (TEFBF) and SDR were chosen due to their distinct ...compositional modifications that enable the decrease of translucency during polymerization and lower polymerization rate, respectively. DC was assessed using FT-Raman spectroscopy at the post-cure times of 0 h, 24 h, 7 d and 30 d. The post-cure behavior was analyzed by a mixed model ANOVA and partial eta-squared statistics.
DC ranged from 61.3-81.1% for TEFBF and 58.9-81.6% for SDR. The initial (0 h) DC was significantly lower at a depth of 4 mm than at a depth of 1 mm (4.9% for SDR and 11.1% for TEFBF). Both materials presented a significant post-cure DC increase, up to 16.4% for TEFBF and 20.6% for SDR. The post-cure DC development was depth-dependent for TEFBF, but not for SDR. The post-cure DC increase was observed during 24 h for TEFBF and 7 d for SDR.
Some of the bulk-fill composites may need longer times than the commonly accepted 24 h to reach the final conversion. This may be attributed to their compositional modifications that are mostly undisclosed by manufacturers. Our findings imply that investigations commonly performed 24 h post-cure may underestimate some of the bulk-fill composite properties, if these are affected by the slowly-developing DC. Reactive species may also be available for leaching out of the restoration during an extended time period, with possible implications on biocompatibility.
Svrha: Istražiti dugoročan razvoj stupnja konverzije (SK) dvaju tekućih bulk-fill kompozita. Materijali i postupci: Tetric EvoFlow Bulk Fill (TEFBF) i SDR izabrani su zbog posebnosti u sastavu koje ...omogućuju smanjenje translucencije tijekom polimerizacije i manju brzinu polimerizacije. SK je izmjeren FT-Ramanovom spektroskopijom nakon 0 i 24 sata te 7 i 30 dana poslije svjetlosne aktivacije. Naknadna polimerizacija analizirana je mješovitim modelom ANOVA-e i parcijalnom eta-kvadrat statistikom. Rezultati: Izmjeren je SK u rasponu od 61,3 do 81,1 posto kad je riječ o TEFBF-u i od 58,9 do
81,6 posto za SDR. Početne (0 sati) vrijednosti SK-a bile su značajno niže na dubini od 4 mm negoli na onoj od 1 mm (4,9 % – SDR i 11,1 % – TEFBF). Oba materijala pokazala su značajan porast SK-a nakon svjetlosne aktivacije – do 16,4 posto TEFBF i 20,6 posto SDR. Naknadni porast SK-a ovisio je o dubini, kad je riječ o TEFBF-u, ali ne i o SDR-u. Naknadni porast SK-a zabilježen je tijekom 24 sata pri uporabi TEFBF-a i sedam dana pri uporabi SDR-a. Zaključak: Pri uporabi nekih bulk-fill kompozita bilo je za postizanje konačnoga SK-a potrebno dulje vrijeme od uobičajeno prihvaćenog razdoblja od 24 sata. To se može pripisati izmjenama u sastavu koje proizvođači najčešće ne otkrivaju. Rezultati sugeriraju da istraživanja koja se uobičajeno obavljaju 24 sata nakon polimerizacije mogu podcijeniti
neka svojstva bulk-fill kompozita, ako ona ovise o spororastućem SK-u. Reaktivni spojevi također mogu biti dostupni za otpuštanje iz restoracije tijekom duljeg razdoblja s mogućim implikacijama na biokompatibilnost.
The aim of this study was to investigate leachable components (monomers) in high and low viscosity dental bulk-fill resin composites and conventional resin composite materials after polymerization. ...Six bulk-fill and six conventional dental resin composite materials were used in this study. The samples of each material (three sets of triplicates) were cured for 20 s with irradiance of 1200 mW/cmsup.2 with a LED curing unit and immersed in a 75% ethanol solution at 37 °C. The eluates from each triplicate set were analyzed after 24 h, 7 days or 28 days using liquid chromatography coupled with triple quadrupole tandem mass spectrometry (LC-MS/MS). Detectable amounts of 2-Hydroxyethyl methacrylate (HEMA) were found in both Gradia materials and the amount observed across different time points was statistically different (p ˂ 0.05), with the amount in solution increasing for Gradia and decreasing for Gradia Direct flo. Bisphenol A diglycidildimethacrylate (BIS GMA) was found in Filtek and Tetric materials. Triethylene glycol dimethacrylate (TEGDMA) was detected in all materials. On the other hand, there were no statistically significant differences in the amounts of TEGDMA detected across different time points in either of the tested materials. Monomers HEMA, TEGDMA, 4-dimethylaminobenzoic acid ethyl ester (DMA BEE) and BIS GMA in bulk-fill and conventional composites (high and low viscosity) can be eluted after polymerization. The good selection of composite material and proper handling, the following of the manufacturer’s instructions for polymerization and the use of finishing and polishing procedures may reduce the elution of the unpolymerized monomers> responsible for the possible allergic and genotoxic potential of dental resin composites.
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