Energy dependent polymerization of resin-based composite

Halvorson, Rolf H; Erickson, Robert L.; Davidson, C.L.

doi:10.1016/s0109-5641(01)00069-0

Cited by 254 publications

(235 citation statements)

References 17 publications

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“…The phenomenon of "dark" post cure is in agreement with the findings of other authors [16,17], but is in contrast to conversion measurements performed by Raman spectroscopy, for which little increase in conversion within 24 h was reported [18,19]. Under wet conditions, the lower conversion in BPDM and IPDM composites is attributed to water absorbed in the composites, which may have poisoned the post-polymerization.…”

Section: Discussionsupporting

confidence: 91%

Degree of cure and fracture properties of experimental acid-resin modified composites under wet and dry conditions

López-Suevos

Dickens

2008

Dental Materials

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Objective-Evaluate the effects of core structure and storage conditions on the mechanical properties of acid-resin modified composites and a control material by three-point bending and conversion measurements 15 min and 24 h after curing.Methods-The monomers pyromellitic dimethacrylate (PMDM), biphenyldicarboxylic-acid dimethacrylate (BPDM), (isopropylidene-diphenoxy)bis(phthalic-acid) dimethacrylate (IPDM), oxydiphthalic-acid dimethacrylate (ODPDM), and Bis-GMA were mixed with triethyleneglycol dimethacrylate (TEGDMA) in a 40/60 molar ratio, and photo-activated. Composite bars (Bariumoxide-glass/resin = 3/1 mass ratio, (2 × 2 × 25) mm, n = 5) were light-cured for 1 min per side. Flexural strength (FS), elastic modulus (E), and work-of-fracture (WoF) were determined in threepoint bending after 15 min (stored dry); and after 24 h under dry and wet storage conditions at 37 °C . Corresponding degrees of conversion (DC) were evaluated by Fourier transform infrared spectroscopy. Data was statistically analyzed (2-way analysis of variance, ANOVA, Holm-Sidak, p < 0.05).Results-Post-curing significantly increased FS, E and DC in nearly all cases. WoF did not change, or even decreased with time. For all properties ANOVA found significant differences and interactions of time and material. Wet storage reduced the moduli and the other properties measured with the exception of FS and WoF of ODPDM; DC only decreased in BPDM and IPDM composites.Significance-Differences in core structure resulted in significantly different physical properties of the composites studied with two phenyl rings connected by one ether linkage as in ODPDM having superior FS, WoF and DC especially after 24 h under wet conditions. As expected, post-curing significantly contributed to the final mechanical properties of the composites, while wet storage generally reduced the mechanical properties.

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Section: Discussionsupporting

confidence: 91%

Degree of cure and fracture properties of experimental acid-resin modified composites under wet and dry conditions

López-Suevos

Dickens

2008

Dental Materials

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“…12,22,23,24 The degree of conversion is an another factor that has an impact on water sorption. 17 When 23 concluded that the reciprocal relationship between radiant exitance and exposure duration is invalid when exposure time is short. The higher sorption value at xtra power mode in comparison with the standard mode for SonicFill can be explained with the results of these previous studies.…”

Section: Discussionmentioning

confidence: 99%

Water sorption and solubility of bulk-fill composites polymerized with a third generation LED LCU

Misilli

Gönülol

2017

Braz. oral res.

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“…Probably, the power density supplied for resin cement during light curing was inadequate to excite photoinitiators at deep areas because of light absorption and scraping by superficial areas (5). The reciprocity between exposure time and light intensity could be also applied to overcome the effects on polymerization depth, once such effects are related to energy supplied for activation (7).…”

Section: Discussionmentioning

confidence: 99%

“…As a consequence, lower degree of conversion is expected from resin cements when the energy is lower than that required for a proper resin cement polymerization, leading to postoperative sensitivity, staining, marginal breaking, poor adhesion between the tooth and the indirect restoration (6), microleakage, secondary caries, and changes in some cement mechanical properties. The degree of conversion depends on the energy supplied during light activation, and can be characterized as the product of light intensity and exposure time (7). The hardness test is a simple and reliable method commonly used as indicative of the degree of conversion of resin cements.…”

Section: Effect Of Thickness Of Indirect Restoration and Distance Fromentioning

confidence: 99%

Effect of thickness of indirect restoration and distance from the light-curing unit tip on the hardness of a dual-cured resin cement

et al. 2010

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This study evaluated the Knoop hardness and polymerization depth of a dual-cured resin cement, light-activated at different distances through different thicknesses of composite resin. One bovine incisor was embedded in resin and its buccal surface was flattened. Dentin was covered with PVC film where a mold (0.8-mm-thick and 5 mm diameter) was filled with cement and covered with another PVC film. Light curing (40 s) was carried out through resin discs (2, 3, 4 or 5 mm) with a halogen light positioned 0, 1, 2 or 3 mm from the resin surface. After storage, specimens were sectioned for hardness measurements (top, center, and bottom). Data were subjected to split-plot ANOVA and Tukey's test (a=0.05). The increase in resin disc thickness decreased cement hardness. The increase in the distance of the light-curing tip decreased hardness at the top region. Specimens showed the lowest hardness values at the bottom, and the highest at the center. Resin cement hardness was influenced by the thickness of the indirect restoration and by the distance between the light-curing unit tip and the resin cement surface.

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Energy dependent polymerization of resin-based composite

Cited by 254 publications

References 17 publications

Degree of cure and fracture properties of experimental acid-resin modified composites under wet and dry conditions

Degree of cure and fracture properties of experimental acid-resin modified composites under wet and dry conditions

Water sorption and solubility of bulk-fill composites polymerized with a third generation LED LCU

Effect of thickness of indirect restoration and distance from the light-curing unit tip on the hardness of a dual-cured resin cement

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