Influence of matrix composition on polymerization stress development of experimental composites

Gonçalves, Flávio de Oliveira; Pfeifer, Carmem S.; Stansbury, Jeffrey W.; Newman, Sheldon M.; Braga, Roberta da Rocha

doi:10.1016/j.dental.2010.03.014

Cited by 83 publications

(63 citation statements)

References 32 publications

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“…This finding it is also supported by the higher DC found in these composites. The higher DC should have improved the cohesive forces of the polymer network of these composites, which became more rigid to deformation and can ensure good clinical performance of these composites (19).…”

Section: Discussionmentioning

confidence: 99%

Influence of Different Concentration and Ratio of a Photoinitiator System on the Properties of Experimental Resin Composites

et al. 2017

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The aim in this study was to evaluate the influence of different ratio of camphorquinone/ tertiary amine concentration on the flexural strength (FS), elastic modulus (EM), degree of conversion (DC), yellowing (YL), water sorption (WS) and water solubility (WSL) of experimental composites. Thus, acrylate blends were prepared with different camphorquinone (CQ) and amine (DABE) concentrations and ratios by weight: (CQ/DABE%): 0.4/0.4% (C1), 0.4/0.8% (C2), 0.6/0.6% (C3), 0.6/1.2% (C4), 0.8/0.8% (C5), 0.8/1.6% (C6), 1.0/1.0% (C7), 1.0/2.0% (C8), 1.5/1.5% (C9), 1.5/3.0% (C10). For the FS and EM, rectangular specimens (7x2x1 mm, n=10) were photo-activated by single-peak LED for 20 s and tested at Instron (0.5 mm/ min). Then, the same specimens were evaluated by FTIR for DC measurement. For YL, disks (5x2 mm, n=10) were prepared, light-cured for 20 s and evaluated in spectrophotometer using the b aspect of the CIEL*a*b* system. For WS and WSL, the volume of the samples was calculated (mm³). For WS and WSL, composites disks (5x0.5 mm, n=5) were prepared. After desiccation, the specimens were stored in distilled water for 7 days and again desiccated, in order to measure the WS and WSL. Data were submitted to one-way ANOVA and Tukey's test (5%). The groups C8, C9 and C10 showed higher DC, EM and YL means, compared to other composites. Therefore, the FS and WS values were similar among all groups. Also, C1, C2 and C3 presented higher WSL in 7 days, compared to other composites. In general, higher concentrations of camphorquinone promoted higher physical-mechanical properties; however, inducing higher yellowing effect for the experimental composites. Influence of Different Concentration a n d R a t i o o f a P h o t o i n i t i a t o r S y s t e m o n t h e P r o p e r t i e s o f Experimental Resin Composites

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Section: Discussionmentioning

confidence: 99%

Influence of Different Concentration and Ratio of a Photoinitiator System on the Properties of Experimental Resin Composites

et al. 2017

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“…9,10 Delaying the acquisition of a high elastic modulus allows the polymer chains to rearrange and accommodate the reduction of volume by plastic deformation. 15 Furthermore, polymerization stress is related mainly to volumetric shrinkage and elastic modulus, both these being closely related to degree of conversion. 15 Panavia F reached the highest values of RP max and degree of conversion when the cements were light activated.…”

Section: Discussionmentioning

confidence: 99%

“…15 Furthermore, polymerization stress is related mainly to volumetric shrinkage and elastic modulus, both these being closely related to degree of conversion. 15 Panavia F reached the highest values of RP max and degree of conversion when the cements were light activated. However, polymerization stress of Panavia F was not different from that of the other cements.…”

Section: Discussionmentioning

confidence: 99%

“…3,13 Unfortunately, a higher degree of conversion is also related to an increase in polymerization shrinkage stress. [14][15][16] If stress exceeds the bond strength between the dental substrate and the adhesive system, a contraction gap will be formed, [17][18][19][20] jeopardizing the longevity of the restoration. It has been demonstrated that lower polymerization rate 21,22 and lower elastic modulus [22][23][24][25] may help reduce polymerization stress.…”

Section: Introductionmentioning

confidence: 99%

“…15 For this material, one drop of each of the primer liquids A and B was mixed for 10 seconds and gently air-dried for 5 seconds to evaporate the solvent. Thereafter, 0.1 lL (1.4 mg) of this solution was dispensed onto a glass slab using a micropipette (model NPX2; Nichipet EX, Santa Clara, CA, USA) and mixed with the base and catalyst pastes (27 mg of each paste) of the dual-cure cement for 15 seconds.…”

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confidence: 99%

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Effect of Immediate or Delayed Light Activation on Curing Kinetics and Shrinkage Stress of Dual-Cure Resin Cements

Faria-e-Silva¹,

Boaro²,

Braga³

et al. 2011

Operative Dentistry

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A Faria-e-Silva L Boaro R Braga E Piva V Arias L Martins Clinical RelevanceUnder clinical conditions, delayed light activation of dual-cured resin cements may be advantageous in order to reduce shrinkage stress. SUMMARYObjectives: This study evaluated the effect of light activation (absence, immediate, or delayed) on conversion kinetics and polymerization stress of three commercial dual-cured resin cements (Enforce, RelyX ARC, and Panavia F). Methods: Degree of conversion (DC) was monitored for 30 minutes using real-time nearFourier transform infrared spectroscopy. The cement was mixed, placed on the spectrometer sample holder, and light activated either immediately or after five minutes (delayed light activation). When no light activation was performed, the materials were protected from light exposure (control). DC was evaluated at five and 30 minutes postmixture. Maximum rates of polymerization (Rp max ) were obtained from the first derivative of the DC vs time curve. Polymerization stress was monitored for 30 minutes in 1-mm-thick specimens inserted between two cylinders attached to a uni-

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Stress reduction in phase‐separated, cross‐linked networks: Influence of phase structure and kinetics of reaction

Szczepanski

Stansbury

2014

J of Applied Polymer Sci

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A mechanism for polymerization shrinkage and stress reduction was developed for heterogeneous networks formed via ambient, photo-initiated polymerization-induced phase separation (PIPS). The material system used consists of a bulk homopolymer matrix of triethylene glycol dimethacrylate (TEGDMA) modified with one of three non-reactive, linear prepolymers (poly-methyl, ethyl and butyl methacrylate). At higher prepolymer loading levels (10–20 wt%) an enhanced reduction in both shrinkage and polymerization stress is observed. The onset of gelation in these materials is delayed to a higher degree of methacrylate conversion (~15–25%), providing more time for phase structure evolution by thermodynamically driven monomer diffusion between immiscible phases prior to network macro-gelation. The resulting phase structure was probed by introducing a fluorescently tagged prepolymer into the matrix. The phase structure evolves from a dispersion of prepolymer at low loading levels to a fully co-continuous heterogeneous network at higher loadings. The bulk modulus in phase separated networks is equivalent or greater than that of poly(TEGDMA), despite a reduced polymerization rate and cross-link density in the prepolymer-rich domains.

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Influence of matrix composition on polymerization stress development of experimental composites

Cited by 83 publications

References 32 publications

Influence of Different Concentration and Ratio of a Photoinitiator System on the Properties of Experimental Resin Composites

Influence of Different Concentration and Ratio of a Photoinitiator System on the Properties of Experimental Resin Composites

Effect of Immediate or Delayed Light Activation on Curing Kinetics and Shrinkage Stress of Dual-Cure Resin Cements

Stress reduction in phase‐separated, cross‐linked networks: Influence of phase structure and kinetics of reaction

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