Polymerization shrinkage, stress, and degree of conversion in silorane- and dimethacrylate-based dental composites

2011 ◽  
Vol 122 (3) ◽  
pp. 1882-1888 ◽  
Author(s):  
Jie Xiong ◽  
Xiang Sun ◽  
Yuncong Li ◽  
Jihua Chen
Keyword(s):  
Degree Of Conversion ◽  
Dental Composites ◽  
Shrinkage Stress ◽  
Polymerization Shrinkage

scholarly journals Influence of Modulated Photo-Activation on Shrinkage Stress and Degree of Conversion of Bulk-Fill Composites

2019 ◽  
Vol 30 (6) ◽  
pp. 592-598 ◽  
Author(s):  
Marilia Mattar de Amoêdo Campos Velo ◽  
Linda Wang ◽  
Adilson Yoshio Furuse ◽  
Letícia Ferreira de Freitas Brianezzi ◽  
Cassiana Koch Scotti ◽  
...  
Keyword(s):  
Testing Machine ◽  
Continuous Light ◽  
High Viscosity ◽  
Degree Of Conversion ◽  
Steel Plates ◽  
Attenuated Total Reflectance ◽  
Shrinkage Stress ◽  
Polymerization Shrinkage ◽  
Low Viscosity ◽  
Universal Testing

Abstract This study aimed to evaluate the polymerization properties of bulk-fill materials (low and high-viscosity) by using high-intensity continuous light and intermittent photo-activation in terms of polymerization shrinkage stress and degree of conversion (DC). The following Bulk-fill and Conventional nanofilled resin composites were evaluated: Filtek Z350XT Flow (3M/ESPE), SureFil SDR Flow (Dentsply), Filtek Bulk Fill Flow (3M/ESPE), Filtek Z350XT (3M/ESPE) and Filtek Bulk Fill Posterior (3M/ESPE). A LED device (DB 685, Dabi Atlante) was used for both protocols: continuous uniform and intermittent photo-activation (light-on and light-off cycles) with identical radiant exposure (14 J/cm2). The polymerization shrinkage stress (n=6) was evaluated by inserting a single increment of 12 mm3 between two stainless steel plates (6×2 mm) adapted to a Universal Testing Machine (UTM), at different times. Measurements were recorded after photo-activation. The degree of conversion was evaluated by Fourier transformed infrared spectroscope (FTIR) with an attenuated total reflectance (ATR) accessory (n=5). Data were analyzed by three-way ANOVA and Tukey’s HSD (α=0.05) tests. Bulk Fill Posterior presented higher shrinkage stress values when photo-activated with the intermittent technique (p<0.05). The intermittent photo-activation increased the degree of conversion for the low-viscosity bulk-fills (p<0.05). Therefore, the use of modulated photo-activation (intermittent) must be indicated with caution since its use can influence the shrinkage stress and degree of conversion of composites, which varies according to the resin formulations.

scholarly journals Polymerization Shrinkage, Shrinkage Stress, and Degree of Conversion in Bulk-Fill Resin Composites After Different Photo-Activation Methods

2020 ◽  
Vol 11 (1) ◽  
pp. 4
Author(s):  
Fatemeh Namdar ◽  
Sara Majidinia ◽  
Hossein Bagheri ◽  
Shadi Ramezani ◽  
MohammadJafari Giv ◽  
...  
Keyword(s):  
Degree Of Conversion ◽  
Shrinkage Stress ◽  
Resin Composites ◽  
Polymerization Shrinkage

scholarly journals Polymerization shrinkage behaviour of resin composites functionalized with unsilanized bioactive glass fillers

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Matej Par ◽  
Dirk Mohn ◽  
Thomas Attin ◽  
Zrinka Tarle ◽  
Tobias T. Tauböck
Keyword(s):  
Bioactive Glass ◽  
Degree Of Conversion ◽  
Stress Rate ◽  
Partial Replacement ◽  
Shrinkage Stress ◽  
Resin Composites ◽  
Dental Resin ◽  
Polymerization Shrinkage ◽  
Reinforcing Fillers ◽  
Shrinkage Behaviour

Abstract Previous work has shown that partial replacement of reinforcing fillers with unsilanized silica particles can diminish polymerization shrinkage stress of dental resin composites. The aim of the present study was to investigate whether such an effect can be attained by using unsilanized bioactive glass (BG). Incorporating BG fillers into resin composites is interesting due to their potential for exerting caries-preventive effects. Experimental light-curable composites with a total filler load of 77 wt% were prepared. Reinforcing fillers were partially replaced with 0–60 wt% of BG 45S5 and an experimental low-sodium fluoride-containing BG. The following properties were investigated: linear shrinkage, degree of conversion, shrinkage stress, maximum shrinkage stress rate, and time to achieve maximum shrinkage stress rate. The diminishing effect of BG 45S5 on shrinkage stress was mediated by a decrease in degree of conversion caused by this BG type. In contrast, as the degree of conversion remained unaffected by the experimental BG, the resulting shrinkage behaviour was governed by the effect of varying amounts of silanized and unsilanized fillers on material’s viscoelastic properties. The replacement of silanized reinforcing fillers with unsilanized BG did not reduce polymerization shrinkage stress unless the reduction was attained indirectly through a diminished degree of conversion.

The Combination of CQ-amine and TPO Increases the Polymerization Shrinkage Stress and Does Not Improve the Depth of Cure of Bulk-fill Composites

2019 ◽  
Vol 44 (5) ◽  
pp. 499-509
Author(s):  
MG Rocha ◽  
DCRS de Oliveira ◽  
MAC Sinhoreti ◽  
JF Roulet ◽  
AB Correr
Keyword(s):  
Near Infrared ◽  
Light Emitting Diode ◽  
Flexural Modulus ◽  
Degree Of Conversion ◽  
Light Transmittance ◽  
Volumetric Shrinkage ◽  
Shrinkage Stress ◽  
Polymerization Shrinkage ◽  
Depth Of Cure ◽  
Three Point Bend Test

SUMMARY Objectives: To evaluate the effect of combining camphorquinone (CQ) and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) on the depth of cure and polymerization shrinkage stress of bulk-fill composites. Methods and Materials: Experimental bulk-fill composites were produced containing equal molar concentrations of either CQ-amine or CQ-amine/TPO. The degree of in-depth conversion through each millimeter of a 4-mm-thick bulk-fill increment was evaluated by Fourier transform near-infrared microspectroscopy using a central longitudinal cross section of the increment of each bulk-fill composite (n=3). Light-transmittance of the multi-wave light-emitting diode (LED) emittance used for photoactivation (Bluephase G2, Ivoclar Vivadent) was recorded through every millimeter of each bulk-fill composite using spectrophotometry. The volumetric shrinkage and polymerization shrinkage stress were assessed using a mercury dilatometer and the Bioman, respectively. The flexural modulus was also assessed by a three-point bend test as a complementary test. Data were analyzed according to the different experimental designs (α=0.05 and β=0.2). Results: Up to 1 mm in depth, adding TPO to CQ-based bulk-fill composites increased the degree of conversion, but beyond 1 mm no differences were found. The light-transmittance of either wavelengths emitted from the multi-wave LED (blue or violet) through the bulk-fill composites were only different up to 1 mm in depth, regardless of the photoinitiator system. Adding TPO to CQ-based bulk-fill composites did not affect volumetric shrinkage but did increase the flexural modulus and polymerization shrinkage stress. Conclusion: Adding TPO to CQ-based bulk-fill composites did not increase the depth of cure. However, it did increase the degree of conversion on the top of the restoration, increasing the polymerization shrinkage stress.

Polymerization shrinkage/stress and dentin bond strength of silorane and dimethacrylate-based dental composites

2011 ◽  
Vol 124 (1) ◽  
pp. 436-443 ◽  
Author(s):  
Yuncong Li ◽  
Xiang Sun ◽  
Jihua Chen ◽  
Jie Xiong ◽  
Xiaoyi Hu
Keyword(s):  
Bond Strength ◽  
Dental Composites ◽  
Shrinkage Stress ◽  
Polymerization Shrinkage

scholarly journals Pulse-delay Curing: Influence of Initial Irradiance and Delay Time on Shrinkage Stress and Microhardness of Restorative Composites

2006 ◽  
Vol 31 (5) ◽  
pp. 610-615 ◽  
Author(s):  
C. S. C. Pfeifer ◽  
R. R. Braga ◽  
J. L. Ferracane
Keyword(s):  
Network Structure ◽  
Delay Time ◽  
Clinical Relevance ◽  
Polymer Network ◽  
Degree Of Conversion ◽  
Shrinkage Stress ◽  
Clinical Use ◽  
Pulse Delay ◽  
Polymerization Shrinkage ◽  
Restorative Composites

Clinical Relevance New photoactivation protocols need to be tested before being recommended for clinical use. This study suggests that pulse-delay curing may be an efficient way to reduce polymerization shrinkage stress without compromising degree of conversion or polymer network structure.

scholarly journals The Photoinitiators Used in Resin Based Dental Composite—A Review and Future Perspectives

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 470
Author(s):  
Andrea Kowalska ◽  
Jerzy Sokolowski ◽  
Kinga Bociong
Keyword(s):  
Current Knowledge ◽  
Biomechanical Properties ◽  
Degree Of Conversion ◽  
Dental Composite ◽  
Polymerization Process ◽  
Dental Composites ◽  
Dental Resin ◽  
Dental Resins ◽  
Light Curing

The presented paper concerns current knowledge of commercial and alternative photoinitiator systems used in dentistry. It discusses alternative and commercial photoinitiators and focuses on mechanisms of polymerization process, in vitro measurement methods and factors influencing the degree of conversion and hardness of dental resins. PubMed, Academia.edu, Google Scholar, Elsevier, ResearchGate and Mendeley, analysis from 1985 to 2020 were searched electronically with appropriate keywords. Over 60 articles were chosen based on relevance to this review. Dental light-cured composites are the most common filling used in dentistry, but every photoinitiator system requires proper light-curing system with suitable spectrum of light. Alternation of photoinitiator might cause changing the values of biomechanical properties such as: degree of conversion, hardness, biocompatibility. This review contains comparison of biomechanical properties of dental composites including different photosensitizers among other: camphorquinone, phenanthrenequinone, benzophenone and 1-phenyl-1,2 propanedione, trimethylbenzoyl-diphenylphosphine oxide, benzoyl peroxide. The major aim of this article was to point out alternative photoinitiators which would compensate the disadvantages of camphorquinone such as: yellow staining or poor biocompatibility and also would have mechanical properties as satisfactory as camphorquinone. Research showed there is not an adequate photoinitiator which can be as sufficient as camphorquinone (CQ), but alternative photosensitizers like: benzoyl germanium or novel acylphosphine oxide photoinitiators used synergistically with CQ are able to improve aesthetic properties and degree of conversion of dental resin.

scholarly journals Photoelastic evaluation of the effect of composite formulation on polymerization shrinkage stress

2012 ◽  
Vol 26 (3) ◽  
pp. 202-208 ◽  
Author(s):  
Karla Mychellyne Costa Oliveira ◽  
Simonides Consani ◽  
Luciano Souza Gonçalves ◽  
William Cunha Brandt ◽  
Renzo Alberto Ccahuana-Vásquez
Keyword(s):  
Shrinkage Stress ◽  
Polymerization Shrinkage
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