scholarly journals Polymerization Shrinkage, Hygroscopic Expansion, Elastic Modulus and Degree of Conversion of Different Composites for Dental Application

2021 ◽  
Vol 5 (12) ◽  
pp. 322
Author(s):  
Alexandre Luiz Souto Borges ◽  
Amanda Maria de Oliveira Dal Piva ◽  
Sabrina Elise Moecke ◽  
Raquel Coutinho de Morais ◽  
João Paulo Mendes Tribst
Keyword(s):  
Elastic Modulus ◽  
Poisson Ratio ◽  
Volume Measurement ◽  
Degree Of Conversion ◽  
Recording Device ◽  
Resin Composites ◽  
Polymerization Shrinkage ◽  
Significant Difference ◽  
Dental Application ◽  
The Impact

Objectives: To characterize the mechanical properties of different resin-composites for dental application. Methods: Thirteen universal dentin shade composites (n = 10) from different manufacturers were evaluated (4 Seasons, Grandio, Venus, Amelogen Plus, P90, Z350, Esthet-X, Amaris, Vita-l-escence, Natural-Look, Charisma, Z250 and Opallis). The polymerization shrinkage percentage was calculated using a video-image recording device (ACUVOL—Bisco Dental) and the hygroscopic expansion was measured after thermocycling aging in the same equipment. Equal volumes of material were used and, after 5 min of relaxation, baseline measurements were calculated with 18 J of energy delivered from the light-curing unit. Specimens were stored in a dry-dark environment for 24 h then thermocycled in distilled water (5–55 °C for 20,000 cycles) with volume measurement at each 5000 cycles. In addition, the pulse-excitatory method was applied to calculate the elastic modulus and Poisson ratio for each resin material and the degree of conversion was evaluated using Fourier transform infrared spectroscopy. Results: The ANOVA showed that all composite volumes were influenced by the number of cycles (α = 0.05). Volumes at 5 min post-polymerization (12.47 ± 0.08 cm3) were significantly lower than those at baseline (12.80 ± 0.09 cm3). With regard to the impact of aging, all resin materials showed a statistically significant increase in volume after 5000 cycles (13.04 ± 0.22 cm3). There was no statistical difference between volumes measured at the other cycle steps. The elastic modulus ranged from 22.15 to 10.06 GPa and the Poisson ratio from 0.54 to 0.22 with a significant difference between the evaluated materials (α = 0.05). The degree of conversion was higher than 60% for all evaluated resin composites.

Does Layering Minimize Shrinkage Stresses in Composite Restorations?

2003 ◽  
Vol 82 (12) ◽  
pp. 967-971 ◽  
Author(s):  
R.H. Kuijs ◽  
W.M.M. Fennis ◽  
C.M. Kreulen ◽  
M. Barink ◽  
N. Verdonschot
Keyword(s):  
Dynamic Process ◽  
Apparent Viscosity ◽  
Poisson Ratio ◽  
Resin Composite ◽  
Time Dependent ◽  
Polymerization Process ◽  
Fe Model ◽  
Resin Composites ◽  
Polymerization Shrinkage ◽  
Simulated Time

Polymerization shrinkage of resin composites may impair restoration longevity. It is hypothesized that layering, rather than bulk, techniques result in less stress in the tooth-restoration complex. The aim of this study was to compare shrinkage stresses for different restorative techniques used for cusp-replacing restorations with direct resin composite. In a 3-D FE model, the dynamic process of shrinkage during polymerization was simulated. Time-dependent parameters (shrinkage, apparent viscosity, Young’s modulus, Poisson ratio, and resulting creep), which change during the polymerization process, were implemented. Six different restorative procedures were simulated: a chemically cured bulk technique, a light-cured bulk technique, and 4 light-cured layering techniques. When polymerization shrinkage is considered, a chemically cured composite shows the least resulting stress. The differences seen among various layering build-up techniques were smaller than expected. The results indicate that the stress-bearing locations are the interface and the cervical part of the remaining cusp.

scholarly journals Polymerization Behavior and Mechanical Properties of High-Viscosity Bulk Fill and Low Shrinkage Resin Composites

2017 ◽  
Vol 42 (6) ◽  
pp. E177-E187 ◽  
Author(s):  
S Shibasaki ◽  
T Takamizawa ◽  
K Nojiri ◽  
A Imai ◽  
A Tsujimoto ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Resin Composite ◽  
High Viscosity ◽  
The Other ◽  
Light Irradiation ◽  
Volumetric Shrinkage ◽  
Resin Composites ◽  
Polymerization Shrinkage

SUMMARY The present study determined the mechanical properties and volumetric polymerization shrinkage of different categories of resin composite. Three high viscosity bulk fill resin composites were tested: Tetric EvoCeram Bulk Fill (TB, Ivoclar Vivadent), Filtek Bulk Fill posterior restorative (FB, 3M ESPE), and Sonic Fill (SF, Kerr Corp). Two low-shrinkage resin composites, Kalore (KL, GC Corp) and Filtek LS Posterior (LS, 3M ESPE), were used. Three conventional resin composites, Herculite Ultra (HU, Kerr Corp), Estelite ∑ Quick (EQ, Tokuyama Dental), and Filtek Supreme Ultra (SU, 3M ESPE), were used as comparison materials. Following ISO Specification 4049, six specimens for each resin composite were used to determine flexural strength, elastic modulus, and resilience. Volumetric polymerization shrinkage was determined using a water-filled dilatometer. Data were evaluated using analysis of variance followed by Tukey's honestly significant difference test (α=0.05). The flexural strength of the resin composites ranged from 115.4 to 148.1 MPa, the elastic modulus ranged from 5.6 to 13.4 GPa, and the resilience ranged from 0.70 to 1.0 MJ/m3. There were significant differences in flexural properties between the materials but no clear outliers. Volumetric changes as a function of time over a duration of 180 seconds depended on the type of resin composite. However, for all the resin composites, apart from LS, volumetric shrinkage began soon after the start of light irradiation, and a rapid decrease in volume during light irradiation followed by a slower decrease was observed. The low shrinkage resin composites KL and LS showed significantly lower volumetric shrinkage than the other tested materials at the measuring point of 180 seconds. In contrast, the three bulk fill resin composites showed higher volumetric change than the other resin composites. The findings from this study provide clinicians with valuable information regarding the mechanical properties and polymerization kinetics of these categories of current resin composite.

scholarly journals Effect of 4-(N,N-dimethylamino)phenethyl Alcohol on Degree of Conversion and Cytotoxicity of Photo-Polymerized CQ-Based Resin Composites

2014 ◽  
Vol 25 (6) ◽  
pp. 538-542 ◽  
Author(s):  
Dayane Carvalho Ramos Salles de Oliveira ◽  
Camila Batista da Silva ◽  
Bruno Vilela Muniz ◽  
Maria C. Volpato ◽  
Ana Rosa Costa ◽  
...  
Keyword(s):  
Organic Matrix ◽  
Human Keratinocytes ◽  
Filler Loading ◽  
Degree Of Conversion ◽  
Control Group ◽  
Resin Composites ◽  
Cytotoxic Effects ◽  
Phenethyl Alcohol ◽  
Significant Difference ◽  
Post Hoc

The aim of this study was to evaluate the degree of conversion (DC) and the cytotoxicity of photo-cured experimental resin composites containing 4-(N,N-dimethylamino)phenethyl alcohol (DMPOH) combined to the camphorquinone (CQ) compared with ethylamine benzoate (EDAB). The resin composites were mechanically blended using 35 wt% of an organic matrix and 65 wt% of filler loading. To this matrix was added 0.2 wt% of CQ and 0.2 wt% of one of the reducing agents tested. 5x1 mm samples (n=5) were previously submitted to DC measurement and then pre-immersed in complete culture medium without 10% (v/v) bovine serum for 1 h or 24 h at 37 °C in a humidifier incubator with 5% CO2 and 95% humidity to evaluate the cytotoxic effects of experimental resin composites using the MTT assay on immortalized human keratinocytes cells. As a result of absence of normal distribution, the statistical analysis was performed using the nonparametric Kruskal-Wallis to evaluate the cytotoxicity and one-way analysis of variance to evaluate the DC. For multiple comparisons, cytotoxicity statistical analyses were submitted to Student-Newman-Keuls and DC analysis to Tukey's HSD post-hoc test (=0.05). No significant differences were found between the DC of DMPOH (49.9%) and EDAB (50.7%). 1 h outcomes showed no significant difference of the cell viability between EDAB (99.26%), DMPOH (94.85%) and the control group (100%). After 24 h no significant difference were found between EDAB (48.44%) and DMPOH (38.06%), but significant difference was found compared with the control group (p>0.05). DMPOH presented similar DC and cytotoxicity compared with EDAB when associated with CQ.

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 The effect of radiation exposure and storage time on the degree of conversion and flexural strength of different resin composites

2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Ragia M. Taher ◽  
Lamiaa M. Moharam ◽  
Amin E. Amin ◽  
Mohamed H. Zaazou ◽  
Farid S. El-Askary ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Radiation Exposure ◽  
Storage Time ◽  
Resin Composite ◽  
Degree Of Conversion ◽  
Bending Test ◽  
Resin Composites ◽  
Significant Difference ◽  
Infrared Spectrometer ◽  
And Storage

Abstract Background This study was conducted to evaluate the effect of radiation exposure and storage time on the degree of conversion (DC%) and flexural strength (FS) of three different resin composites. In total, 90 disk-shaped, and 360 rod-shaped composite specimens were prepared to evaluate the DC% and FS, respectively. Specimens were divided into 18 groups (DC%: n = 5 and FS: n = 20) according to the three experimental factors of the study: 1—Radiation (no-exposure and exposure), 2—Resin composite material (Herculite XRV Ultra, Z250 XT and Grandio), and 3—Storage time (24 h in distilled water, 3-m and 6-m in 70% ethanol). Fourier transform infrared spectrometer (FTIR) was used to determine the DC%. For FS, the specimens were subjected to a three-point bending test at 1 mm/min crosshead speed. Data were analyzed using three-way ANOVA/Tukey HSD test. Significant level was set at P = 0.05. Results For DC%, there was no significant difference between no-radiation exposure and radiation exposure (P > 0.05). Herculite XRV Ultra revealed the highest statistically significant DC% (P < 0.05). The 24-h storage time revealed the least significant DC% (P < 0.05). For FS, radiation exposure showed a statistically significant higher value compared to no-radiation exposure (P < 0.05). Herculite XRV Ultra showed the least FS value (P < 0.05). The 24-h storage time showed the highest significant value (P < 0.05). Conclusions Radiation exposure has no significant impact on the DC% of the different resin composites, but it has a significant positive effect on the FS. Storage time had a significant effect on both DC% and FS.

scholarly journals Polymerization shrinkage kinetics and degree of conversion of resin composites

2020 ◽  
Vol 62 (3) ◽  
pp. 275-280
Author(s):  
Tong Xu ◽  
Xuan Li ◽  
Han Wang ◽  
Gang Zheng ◽  
Gaigai Yu ◽  
...  
Keyword(s):  
Degree Of Conversion ◽  
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.

Degree of Conversion and Polymerization Shrinkage of Bulk-Fill Resin-Based Composites

2017 ◽  
Vol 42 (1) ◽  
pp. 82-89 ◽  
Author(s):  
P Yu ◽  
AUJ Yap ◽  
XY Wang
Keyword(s):  
Light Emitting Diode ◽  
Degree Of Conversion ◽  
Attenuated Total Reflectance ◽  
Polymerization Shrinkage ◽  
Light Emitting ◽  
Significant Difference ◽  
Before And After ◽  
Light Curing ◽  
Curing Light ◽  
The Mean

SUMMARY This study evaluated the degree of conversion (DC) and polymerization shrinkage (PS) of contemporary bulk-fill resin-based composites (RBCs) including giomer materials. Two giomer bulk-fill (Beautifil Bulk Restorative [BBR], Beautifil Bulk Flowable [BBF]), two nongiomer bulk-fill (Tetric N-Ceram Bulk-fill [TNB], Smart Dentin Replacement [SDR]), and three conventional non–bulk-fill (Beautifil II [BT], Beautifil Flow Plus [BF], Tetric N-Ceram [TN]) RBCs were selected for the study. To evaluate the DC, disc-shaped specimens of 5-mm diameter and 2-mm, 4-mm, and 6-mm thickness were fabricated using customized Teflon molds. The molds were bulk filled with the various RBCs and cured for 20 seconds using a light-emitting diode curing light with an irradiance of 950 mW/cm2. The DC (n=3) was determined by attenuated total reflectance Fourier transform infrared spectroscopy by computing the spectra of cured and uncured specimens. PS (n=3) was measured with the Acuvol volumetric shrinkage analyzer by calculating specimen volumes before and after light curing. The mean DC for the various materials ranged from 46.03% to 69.86%, 45.94% to 69.38%, and 30.65% to 67.85% for 2 mm, 4 mm, and 6 mm, respectively. For all depths, SDR had the highest DC. While no significant difference in DC was observed between depths of 2 mm and 4 mm for the bulk-fill RBCs, DC at 2 mm was significantly greater than 6 mm. For the conventional RBCs, DC at 2 mm was significantly higher than at 4 mm and 6 mm. Mean PS ranged from 1.48% to 4.26% for BBR and BF, respectively. The DC at 2 mm and PS of bulk-fill RBCs were lower than their conventional counterparts. At 4 mm, the DC of giomer bulk-fill RBCs was lower than that of nongiomer bulk-fill materials.

scholarly journals Examining the Effect of Radiant Exposure on Commercial Photopolimerizable Dental Resin Composites

2018 ◽  
Vol 6 (4) ◽  
pp. 55 ◽  
Author(s):  
Carlos Cuevas-Suárez ◽  
Belinda Pimentel-García ◽  
Alejandro Rivera-Gonzaga ◽  
Carlos Álvarez-Gayosso ◽  
Adriana Ancona-Meza ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Water Sorption ◽  
Water Solubility ◽  
Light Exposure ◽  
Physical And Mechanical Properties ◽  
Degree Of Conversion ◽  
Resin Composites ◽  
Dental Resin ◽  
Radiant Exposure ◽  
Dental Resin Composites

The objective of this study was to evaluate the effect of radiant exposure on the chemical and physical properties of four commercial dental resin composites. The four dental resin composites used were Kalore, Admira, Tetric N-Ceram Bulk Fill, and Filtek Z350 XT. The composites were subjected to three curing protocols: 1000 mW/cm2 for 5 s, 1000 mW/cm2 for 10 s, and 400 mW/cm2 for 25 s. The flexural strength, elastic modulus, water sorption, water solubility, degree of conversion, and polymerization shrinkage were evaluated. The results were analyzed by means of ANOVA and Tukey tests. For Admira and Kalore, significant differences between light exposure protocols were observed for the elastic modulus (p < 0.001), which was higher when a higher amount of radiant exposure was used. For Filtek Z350, differences were only observed for the degree of conversion (p < 0.001), and a higher amount of radiant exposure allowed us to obtain higher values. The Tetric N-Ceram Bulk Fill analysis showed significant differences for the elastic modulus and water sorption (p < 0.001), and specimens that had been subject to a radiant exposure of 10 J/cm2 showed a higher elastic modulus. In most cases, the physical and mechanical properties analyzed were not affected by different radiant exposure values. Other resin-based composite (RBC) characteristics seem to have a greater influence on material properties.

Measuring Impact of Stress in Sandwich Generation Caring for Demented Parents

GeroPsych ◽  
2014 ◽  
Vol 27 (4) ◽  
pp. 171-179 ◽  
Author(s):  
Laurence M. Solberg ◽  
Lauren B. Solberg ◽  
Emily N. Peterson
Keyword(s):  
Factor Analysis ◽  
Exploratory Factor Analysis ◽  
Social Worker ◽  
Resource Availability ◽  
Well Being ◽  
Sandwich Generation ◽  
Item Questionnaire ◽  
Significant Difference ◽  
Adult Caregivers ◽  
The Impact

Stress in caregivers may affect the healthcare recipients receive. We examined the impact of stress experienced by 45 adult caregivers of their elderly demented parents. The participants completed a 32-item questionnaire about the impact of experienced stress. The questionnaire also asked about interventions that might help to reduce the impact of stress. After exploratory factor analysis, we reduced the 32-item questionnaire to 13 items. Results indicated that caregivers experienced stress, anxiety, and sadness. Also, emotional, but not financial or professional, well-being was significantly impacted. There was no significant difference between the impact of caregiver stress on members from the sandwich generation and those from the nonsandwich generation. Meeting with a social worker for resource availability was identified most frequently as a potentially helpful intervention for coping with the impact of stress.

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