The degree of conversion of fiber-reinforced composites polymerized using different light-curing sources

Üçtaşli, Sadullah; Tezvergıl, Arzu; Lassila, Lippo; Vallittu, PK

doi:10.1016/j.dental.2004.08.001

Cited by 39 publications

(22 citation statements)

References 23 publications

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“…In addition, the higher degree of conversion of Rebilda DC might be related with its lower viscosity. Lower viscosity results in greater DC％ increasing the mobility of molecules 24) . This study also compared the effects of threestep total-etch technique against two-step self-etch technique.…”

Section: Discussionmentioning

confidence: 99%

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Influence of Polymerization Mode on Degree of Conversion and Micropush-out Bond Strength of Resin Core Systems Using Different Adhesive Systems

et al. 2008

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The aim of this study was to evaluate the influence of different polymerization modes on degree of conversion and micropush-out bond strength of dual-polymerized resin core systems to dentin by using two different adhesive systems. Two resin core systems, Rebilda DC and Build-It FR, were used in combination with total-etch (Adper Scotchbond Multi-Purpose) and self-etch (Clearfil SE Bond) adhesive systems. After treatment of dentin surfaces, resin core systems were applied into the cavities and subjected to different polymerization modes as follows: (1) chemical polymerization; (2) dual polymerization with standard mode of LED (Elipar FreeLight 2 LED); or (3) dual polymerization with exponential mode of LED. The cavities (n=10 per group) were tested in a universal testing machine. Degree of monomer conversion (DC%) was determined by Fourier transform infrared spectroscopy (n=5 cavities per group). ANOVA revealed that resin core (p=0.002), adhesive system (p<0.001), and polymerization mode (p<0.001) had significant effects on bond strength values. The degree of conversion for resin cores decreased significantly (p<0.001) when only chemical polymerization was employed.

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Section: Discussionmentioning

confidence: 99%

“…Thus, no oxygen was present on the resin surface to cause oxygen inhibition of the resin. DC％ was calculated from the aliphatic C＝ C peak at 1638 cm -1 and normalized against the aromatic C＝C peak at 1608 cm -1 according to the following formula 24) :…”

Section: Degree Of Conversion Analysismentioning

confidence: 99%

Influence of Polymerization Mode on Degree of Conversion and Micropush-out Bond Strength of Resin Core Systems Using Different Adhesive Systems

et al. 2008

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“…Adequate polymerization results in enhanced physical properties [19] and decreased cytotoxicity of dimethacrylate-based composites [20]. Different factors such as filler particle size and loading, polymerization initiator concentration [21,22], monomer type and amount, the shade and translucency of the material [23], intensity and wavelength of the light source, as well as irradiation time [24] can influence the DC of dental composite materials. DC is frequently measured to evaluate photopolymerization efficiency by spectroscopic techniques that infer the quantity of remaining double bonds, either mid-infrared Fourier transform (FT) spectroscopy [25], Raman spectroscopy [26] or near-infrared FT spectroscopy (FT NIR) [27].…”

Section: Introductionmentioning

confidence: 99%

Influence of irradiation time on subsurface degree of conversion and microhardness of high-viscosity bulk-fill resin composites

et al. 2014

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OBJECTIVES To evaluate the influence of irradiation time on degree of conversion (DC) and microhardness of high-viscosity bulk-fill resin composites in depths up to 6 mm. MATERIALS AND METHODS Four bulk-fill materials (Tetric EvoCeram Bulk Fill-TECBF; x-tra fil-XF; QuixFil-QF; SonicFill-SF) and one conventional nano-hybrid resin composite (Tetric EvoCeram-TEC) were irradiated for 10, 20, or 30 s at 1,170 mW/cm(2). DC and Knoop microhardness (KHN) were recorded after 24-h dark storage at five depths: 0.1, 2, 4, 5, and 6 mm. Data were statistically analyzed using ANOVA and Bonferroni's post-hoc test ( = 0.05). RESULTS With increasing bulk thickness, DC and KHN significantly decreased for TEC. TECBF and SF showed a significant decrease in DC and KHN at 4-mm depth after 10-s irradiation, but no decrease in DC after 30-s irradiation (p > 0.05). XF and QF demonstrated no significant DC decrease at depths up to 6 mm after irradiation of at least 20 s. At 4-mm depth, all materials tested achieved at least 80 % of their maximum DC value, irrespective of irradiation time. However, at the same depth (4 mm), only XF and QF irradiated for 30 s achieved at least 80 % of their maximum KHN value. CONCLUSIONS Regarding DC, the tested bulk-fill resin composites can be safely used up to at least 4-mm incremental thickness. However, with respect to hardness, only XF and QF achieved acceptable results at 4-mm depth with 30 s of irradiation. CLINICAL RELEVANCE Minimum irradiation times stated by the manufacturers cannot be recommended for placement of highviscosity bulk-fill materials in 4-mm increments. Conclusions: Regarding DC, the tested bulk-fill resin composites can be safely used up to at least 4-mm incremental thickness. However, with respect to hardness, only XF and QF achieved acceptable results at 4-mm depth with 30 s of irradiation.Clinical relevance: Minimum irradiation times stated by the manufacturers cannot be recommended for placement of high-viscosity bulk-fill materials in 4-mm increments.

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“…The degree of monomer conversion after polymerization was measured by Fourier transformation infrared spectroscopy (FTIR, FT/IR-460, JASCO), and was determined from the aliphatic and aromatic C=C peaks for unpolymerized and polymerized resin 19) . For unpolymerized resin, a small amount of resin monomer was placed between two KBr disks, and the spectrum was recorded in transmission mode over the range of 4,000 to 400 cm -1 at a resolution 1 cm -1 .…”

Section: Degree Of Monomer Conversionmentioning

confidence: 99%

Effect of various visible light photoinitiators on the polymerization and color of light-activated resins

et al. 2009

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The purpose of this study was to investigate effects of various visible light photoinitiators on the polymerization efficiency and color of the light-activated resins. Four photoinitiators, including camphorquinone, phenylpropanedione, monoacrylphosphine oxide (TPO), and bisacrylphosphine oxide (Ir819), were used. Each photoinitiator was dissolved in a Bis-GMA and TEGDMA monomer mixture. Materials were polymerized using dental quartz-tungsten halogen lamp (QTH), plasma-ark lamp and blue LED light-curing units, and a custom-made violet LED light unit. The degree of monomer conversion and CIE L*a*b* color values of the resins were measured using a FTIR and spectral transmittance meter. The degree of monomer conversions of TPO-and Ir819-containing resins polymerized with the violet-LED unit were higher than camphorquinone-containing resin polymerized with the QTH light-curing unit. The lowest color values were observed for the TPO-containing resin.Our results indicate that the TPO photoinitiator and the violet-LED light unit may provide a useful and improved photopolymerization system for dental light-activated resins.

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The degree of conversion of fiber-reinforced composites polymerized using different light-curing sources

Cited by 39 publications

References 23 publications

Influence of Polymerization Mode on Degree of Conversion and Micropush-out Bond Strength of Resin Core Systems Using Different Adhesive Systems

Influence of Polymerization Mode on Degree of Conversion and Micropush-out Bond Strength of Resin Core Systems Using Different Adhesive Systems

Influence of irradiation time on subsurface degree of conversion and microhardness of high-viscosity bulk-fill resin composites

Effect of various visible light photoinitiators on the polymerization and color of light-activated resins

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