Filler Content, Surface Microhardness, and Rheological Properties of Various Flowable Resin Composites

SUMMARY Objectives: The objectives of this study were to determine the filler content, the surface microhardness (at baseline and after immersion in water for 2 years), and the rheological properties of various flowable resin composites. Methods: Three flowable resin composites (Grandioso Heavy Flow [GHF], Grandio Flow [GRF], Filtek Supreme XTE Flow [XTE]), one pit and fissure sealant resin composite (ClinPro [CLI]), and three experimental flowable resin composites with the same matrix and a variable filler content (EXPA, EXPB, EXPC) were tested. The filler content was determined by calcination. The Vickers surface microhardness was determined after polymerization and then after immersion in distilled water at 37°C for 7, 60, 180, 360, and 720 days. The rheological measurements were performed using a dynamic shear rheometer. Results: The determined filler contents differed from the manufacturers' data for all the materials. The materials with the highest filler content presented the highest microhardness, but filler content did not appear to be the only influencing parameter. With respect to the values recorded after photopolymerization, the values were maintained or increased after 720 days compared with the initial microhardness values, except for GHF. For the values measured after immersion for 7 days, an increase in microhardness was observed for all the materials over time. All the materials were non-Newtonian, with shear-thinning behavior. At all the shear speeds, GRF presented a lower viscosity to GHF and XTE. Conclusions: GRF presented a low viscosity before photopolymerization, associated with high filler content, thereby providing a good compromise between spreadability and mechanical properties after photopolymerization.

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Effect of Heat and Sonic Vibration on Penetration of a Flowable Resin Composite Used as a Pit and Fissure Sealant

Journal of Clinical Pediatric Dentistry ◽

10.17796/1053-4625-44.1.7 ◽

2020 ◽

Vol 44 (1) ◽

pp. 41-46

Author(s):

Hae-Jung Kim ◽

Hyung-Jun Choi ◽

Ki-Yeol Kim ◽

Kwang-Mahn Kim

Keyword(s):

Flexural Strength ◽

Resin Composite ◽

Optical Microscope ◽

Resin Composites ◽

Third Molars ◽

Fissure Sealant ◽

Application Method ◽

Occlusal Surfaces ◽

Pit And Fissure Sealant ◽

Application Methods

Objective: To evaluate penetration of a flowable resin composite into fissures using three different application methods: (1) conventional, (2) heat, and (3) sonic vibration. Study design: Forty-five sound maxillary third molars were divided randomly into three groups (n=15 per group). The occlusal surfaces of the teeth were etched and flowable resin composites were applied into the fissure using the assigned application method. The crowns were sectioned and examined with an optical microscope to assess penetration. In addition, three-point flexural strength was analyzed. Results: The sonic vibration group exhibited significantly greater penetration into the fissure compared with the other test groups (p<0.001). The heat group exhibited greater penetration into the fissure compared with the conventional group (p=0.003). However, three-point flexural strength was similar among all groups (p>0.05). Conclusions: Sonic vibration and heat increased penetration into fissures. Notably, sonic vibration exhibited the greatest penetration. We found that the application method did not influence the three-point flexural strength.

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Bonding Interaction and Shrinkage Stress of Low-viscosity Bulk Fill Resin Composites With High-viscosity Bulk Fill or Conventional Resin Composites

Operative Dentistry ◽

10.2341/18-163-l ◽

2019 ◽

Vol 44 (6) ◽

pp. 625-636 ◽

Cited By ~ 3

Author(s):

ER Cerda-Rizo ◽

M de Paula Rodrigues ◽

ABF Vilela ◽

SSL Braga ◽

LRS Oliveira ◽

...

Keyword(s):

Failure Mode ◽

Resin Composite ◽

High Viscosity ◽

Shrinkage Stress ◽

Resin Composites ◽

Posterior Teeth ◽

Low Viscosity ◽

Bonding Interaction ◽

Significant Difference ◽

Chi Square Analysis

SUMMARY Objective: To analyze the shrinkage stress, bonding interaction, and failure modes between different low-viscosity bulk fill resin composites and conventional resin composites produced by the same manufacturer or a high-viscosity bulk fill resin composite used to restore the occlusal layer in posterior teeth. Methods & Materials: Three low-viscosity bulk fill resin composites were associated with the conventional resin composites made by the same manufacturers or with a high-viscosity bulk fill resin composite, resulting in six groups (n=10). The bonding interaction between resin composites was tested by assessing the microshear bond strength (μSBS). The samples were thermocycled and were tested with 1-mm/min crosshead speed, and the failure mode was evaluated. The post-gel shrinkage (Shr) of all the resin composites was measured using a strain gauge (n=10). The modulus of elasticity (E) and the hardness (KHN) were measured using the Knoop hardness test. Two-dimensional finite element models were created for analyzing the stress caused by shrinkage and contact loading. The μSBS, Shr, E, and KHN data were analyzed using the Student t-test and one-way analysis of variance. The failure mode data were subjected to chi-square analysis (α=0.05). The stress distribution was analyzed qualitatively. Results: No significant difference was verified for μSBS between low-viscosity bulk fill resin composites and conventional or high-viscosity bulk fill composites in terms of restoring the occlusal layer (p=0.349). Cohesive failure of the low-viscosity bulk fill resin composites was the most frequent failure mode. The Shr, E, and KHN varied between low-viscosity and high-viscosity resin composites. The use of high-viscosity bulk fill resin composites on the occlusal layer reduced the stress at the enamel interface on the occlusal surface. Conclusions: The use of high-viscosity bulk fill resin composites as an occlusal layer for low-viscosity bulk fill resin composites to restore the posterior teeth can be a viable alternative, as it shows a similar bonding interaction to conventional resin composites as well as lower shrinkage stress at the enamel margin.

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Bulk-Fill Resin Composites: Polymerization Contraction, Depth of Cure, and Gap Formation

Operative Dentistry ◽

10.2341/13-324-l ◽

2015 ◽

Vol 40 (2) ◽

pp. 190-200 ◽

Cited By ~ 86

Author(s):

AR Benetti ◽

C Havndrup-Pedersen ◽

D Honoré ◽

MK Pedersen ◽

U Pallesen

Keyword(s):

Resin Composite ◽

Class Ii ◽

High Viscosity ◽

International Organization ◽

Resin Composites ◽

Gap Formation ◽

Depth Of Cure ◽

Low Viscosity ◽

Dental Cavities ◽

Fill Materials

SUMMARY The bulk-filling of deep, wide dental cavities is faster and easier than traditional incremental restoration. However, the extent of cure at the bottom of the restoration should be carefully examined in combination with the polymerization contraction and gap formation that occur during the restorative procedure. The aim of this study, therefore, was to compare the depth of cure, polymerization contraction, and gap formation in bulk-fill resin composites with those of a conventional resin composite. To achieve this, the depth of cure was assessed in accordance with the International Organization for Standardization 4049 standard, and the polymerization contraction was determined using the bonded-disc method. The gap formation was measured at the dentin margin of Class II cavities. Five bulk-fill resin composites were investigated: two high-viscosity (Tetric EvoCeram Bulk Fill, SonicFill) and three low-viscosity (x-tra base, Venus Bulk Fill, SDR) materials. Compared with the conventional resin composite, the high-viscosity bulk-fill materials exhibited only a small increase (but significant for Tetric EvoCeram Bulk Fill) in depth of cure and polymerization contraction, whereas the low-viscosity bulk-fill materials produced a significantly larger depth of cure and polymerization contraction. Although most of the bulk-fill materials exhibited a gap formation similar to that of the conventional resin composite, two of the low-viscosity bulk-fill resin composites, x-tra base and Venus Bulk Fill, produced larger gaps.

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Effects of Color Modifier on Degree of Monomer Conversion, Biaxial Flexural Strength, Surface Microhardness, and Water Sorption/Solubility of Resin Composites

Polymers ◽

10.3390/polym13223902 ◽

2021 ◽

Vol 13 (22) ◽

pp. 3902

Author(s):

Pipop Saikaew ◽

Patchara Phimolthares ◽

Pheeratas Phitakthanaakul ◽

Panthira Sirikul ◽

Suwannee Mekrakseree ◽

...

Keyword(s):

Flexural Strength ◽

Water Sorption ◽

Resin Composite ◽

Physical And Mechanical Properties ◽

Monomer Conversion ◽

Resin Composites ◽

Curing Time ◽

Surface Microhardness ◽

Biaxial Flexural Strength ◽

Group 1

Color modifiers can be mixed with resin composites to mimic the shade of severely discolored tooth. The aim of this study was to assess the effects of a color modifier on the physical and mechanical properties of a resin composite. The composite was mixed with a color modifier at 0 wt% (group 1), 1 wt% (group 2), 2.5 wt% (group 3), or 5 wt% (group 4). The degree of monomer conversion (DC) was examined after light curing for 20 or 40 s. Biaxial flexural strength (BFS)/modulus (BFM), surface microhardness (SH), and water sorption (Wsp)/solubility (Wsl) were also tested. The DC of group 1 was significantly higher than that of groups 3 and 4. The increase in curing time from 20 to 40 s increased the DC by ~10%. The BFS, BFM, Wsp, and Wsl of all the groups were comparable. A negative correlation was detected between the concentration of color modifier and the BFS and DC, while a positive correlation was observed with Wsp. In conclusion, the color modifier reduced the DC of composites, but the conversion was improved by extending the curing time. The increase in color modifier concentration also correlated with a reduction in strength and the increase in the water sorption of the composites.

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Training and educational needs in pit and fissure sealant application for graduate dental personnel: continuing education and certification courses

Journal of Dental Education ◽

10.1002/j.0022-0337.1984.48.2.tb01757.x ◽

1984 ◽

Vol 48 (2) ◽

pp. 66-74

Author(s):

L Scheirton

Keyword(s):

Continuing Education ◽

Educational Needs ◽

Fissure Sealant ◽

Pit And Fissure Sealant

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Pit and fissure sealant in individual patient care programs

Journal of Dental Education ◽

10.1002/j.0022-0337.1984.48.2.tb01753.x ◽

1984 ◽

Vol 48 (2) ◽

pp. 42-44

Author(s):

RJ Simonsen

Keyword(s):

Patient Care ◽

Fissure Sealant ◽

Pit And Fissure Sealant

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Rheological and Microbiological Characteristics of Hops and Hot Trub Particles Formed during Beer Production

Molecules ◽

10.3390/molecules26030681 ◽

2021 ◽

Vol 26 (3) ◽

pp. 681

Author(s):

Monika Sterczyńska ◽

Marek Zdaniewicz ◽

Katarzyna Wolny-Koładka

Keyword(s):

Rheological Properties ◽

Raw Materials ◽

Raw Material ◽

Microbiological Analysis ◽

Waste Products ◽

Low Viscosity ◽

Post Process ◽

High Shear Rates ◽

Different Temperatures ◽

Beer Production

During the production of beer, and especially beer wort, the main wastes are spent grain and hot trub, i.e., the so-called “hot break.” Combined with yeast after fermentation, they represent the most valuable wastes. Hot trub is also one of the most valuable by-products. Studies on the chemical composition of these sediments and their rheological properties as waste products will contribute to their effective disposal and even further use as valuable pharmaceutical and cosmetic raw materials. So far, hot trub has been studied for morphology and particle distribution depending on the raw material composition and beer wort extract. However, there are no preliminary studies on the rheological properties of hot trub and hops. In particular, no attention has yet been paid to the dependence of these properties on the hop variety or different protein sources used. The aim of this study was to examine the effect of different hopping methods on hot trub viscosity and beer wort physicochemical parameters. Additionally, the hop solutions were measured at different temperatures. A microbiological analysis of hop sediments was also performed to determine the post-process survival of selected microorganisms in these wastes. For manufacturers of pumps used in the brewing industry, the most convenient material is that of the lowest viscosity. Low viscosity hot trub can be removed at lower velocities, which reduces costs and simplifies washing and transport. The sediments also had similar equilibrium viscosity values at high shear rates.

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A novel route to improve the mechanical and rheological properties of HTPE/AP/Al propellant by adding a modified hyperbranched polyester

High Performance Polymers ◽

10.1177/0954008320983435 ◽

2020 ◽

pp. 095400832098343

Author(s):

Xiaomu Wen ◽

Ximing Zhang ◽

Keke Chen ◽

Yunjun Luo

Keyword(s):

Rheological Properties ◽

Solid Propellant ◽

Casting Process ◽

Hyperbranched Polyester ◽

Low Viscosity ◽

Composite Solid Propellant ◽

Static Tensile ◽

Void Structure ◽

Composite Solid ◽

Hyperbranched Structure

Both better mechanical and rheological properties are pursued for composite solid propellant. In this work, varying proportions of a modified hyperbranched polyester (MHBPE) were added to HTPE/AP/Al propellant. The static tensile property as one kind of mechanical properties of MHBPE/HTPE/AP/Al propellant were found to be superior to those of blank HTPE/AP/Al propellant as a result of the entanglement and interpenetration of molecular chains caused by the introduction of the hyperbranched structure. Evaluations on the related improved creep resistance and stress relaxation performance further demonstrated the advantages of introduction of MHBPE to HTPE/AP/Al propellant. Rheological properties of HTPE/AP/Al propellant with and without MHBPE during the casting process were investigated and compared and the results confirmed the improvement benefiting from low viscosity and loose void structure. Thus, modified hyperbranched polyester provided a novel route to potentially meet the requirements for propellant manufacturing and applications.

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