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.

Polymerization shrinkage-stress kinetics of resin-composites

2014 ◽  
Vol 30 ◽  
pp. e57
Author(s):  
H. Al-Sunbul ◽  
N. Silikas ◽  
D.C. Watts
Keyword(s):  
Shrinkage Stress ◽  
Resin Composites ◽  
Polymerization Shrinkage ◽  
Kinetics Of

Polymerization Shrinkage Stress Kinetics and Related Properties of Bulk-fill Resin Composites

2014 ◽  
Vol 39 (4) ◽  
pp. 374-382 ◽  
Author(s):  
HM El-Damanhoury ◽  
JA Platt
Keyword(s):  
Standard Procedure ◽  
Stress Rate ◽  
Shrinkage Stress ◽  
Resin Composites ◽  
Polymerization Shrinkage ◽  
Significance Level ◽  
Microhardness Data ◽  
Knoop Microhardness ◽  
Kinetics Of ◽  
Fill Materials

SUMMARY The present study assessed the polymerization shrinkage stress kinetics of five low-shrinkage light-cured bulk-fill resin composites: Surefil SDR flow (SF, Dentsply), Tetric EvoCeram Bulkfil (TE, Ivoclar Vivadent), Venus Bulk Fill (VB, Heraeus Kulzer), x-tra fil (XF, Voco), and experimental bulk fill (FB, 3M ESPE). Filtek Z250 (FZ, 3M ESPE) was used as a control. Real-time shrinkage stress of investigated composites was measured using a tensometer; maximum shrinkage stress, stress rate (Rmax), and time to reach maximum stress rate (tmax) were recorded. Flexural strength and modulus were measured using a standard procedure, and curing efficiency of 4-mm long specimens was determined using bottom/top percentage Knoop microhardness. Data were analyzed using one-way analysis of variance and Bonferroni multiple range tests at a significance level of α=0.05. Results of shrinkage stress, Rmax, and tmax of all bulk-fill materials were significantly lower (p<0.05) than those of the control except for XF. All tested bulk-fill materials were able to achieve acceptable curing efficiency (≥80% bottom/top percentage) at 4-mm depth. In conclusion, this study reports a significant reduction in polymerization shrinkage stress while maintaining comparable curing efficiency at 4 mm for some bulk-fill composites and supports their potential use in posterior clinical situations.

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.

Polymerization Shrinkage and Depth of Cure of Bulk-Fill Resin Composites and Highly Filled Flowable Resin

2015 ◽  
Vol 40 (2) ◽  
pp. 172-180 ◽  
Author(s):  
J-H Jang ◽  
S-H Park ◽  
I-N Hwang
Keyword(s):  
Surface Hardness ◽  
Bottom Surface ◽  
Shrinkage Stress ◽  
Internal Diameter ◽  
Resin Composites ◽  
Polymerization Shrinkage ◽  
Depth Of Cure ◽  
Custom Made ◽  
Polymerization Behavior ◽  
The Mean

SUMMARY The aim of this study was to evaluate the polymerization behavior and depth of cure (DOC) of recently introduced resin composites for posterior use: highly filled flowable composite and composites for bulk fill. A highly filled flowable (G-aenial Universal Flo [GUF]), two bulk-fill flowables (Surefil SDR Flow [SDR] and Venus Bulk fill [VBF]), and a bulk-fill nonflowable composite (Tetric N-Ceram Bulk fill [TBF]) were compared with two conventional composites (Tetric Flow [TF], Filtek Supreme Ultra [FS]). Linear polymerization shrinkage and polymerization shrinkage stress were each measured with custom-made devices. To evaluate DOC, the composite specimen was prepared using a mold with a hole of 4 mm depth and 4 mm internal diameter. The hole was bulk filled with each of the six composites and light cured for 20 seconds, followed by 24 hours of water storage. The surface hardness was measured on the top and the bottom using a Vickers microhardness (HV) indenter. The linear polymerization shrinkage of the composite specimens after photo-initiation decreased in the following order: TF and GUF &gt; VBF &gt; SDR &gt; FS and TBF (p&lt;0.05). The polymerization shrinkage stress of the six composite groups decreased in the following order: GUF &gt; TF and VBF &gt; SDR &gt; FS and TBF (p&lt;0.05). The mean bottom surface HV of SDR and VBF exceeded 80% of the top surface HV (HV-80%). However, the bottom of GUF and TBF failed to reach HV-80%. A highly filled flowable (GUF) revealed limitations in polymerization shrinkage and DOC. Bulk-fill flowables (SDR and VBF) were properly cured in 4-mm bulk, but they shrank more than the conventional nonflowable composite. A bulk-fill nonflowable (TBF) showed comparable shrinkage to the conventional nonflowable composite, but it was not sufficiently cured in the 4-mm bulk.

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