Assessment of polymerization shrinkage of different bulk-fill resin composites

The development of composite materials is subject to the desire to overcome polymerization shrinkage and generated polymerization stress. An indicator characterizing the properties of restorative materials, with specific importance for preventing secondary caries, is the integrity and durability of marginal sealing. It is a reflection of the effects of polymerization shrinkage and generated stress. The present study aimed to evaluate and correlate marginal integrity and micropermeability in second-class cavities restored with three different types of composites, representing different strategies to reduce polymerization shrinkage and stress: nanocomposite, silorane, and bulk-fill composite after a ten-month ageing period. Thirty standardized class ΙΙ cavities were prepared on extracted human molars. Gingival margins were 1 mm apical to the cementoenamel junction. Cavities were randomly divided into three groups, based on the composites used: FiltekUltimate-nanocomposite; Filtek Silorane LS-silorane; SonicFill-bulk-fill composite. All specimens were subjected to thermal cycles after that, dipped in saline for 10-mounds. After ageing, samples were immersed in a 2% methylene blue. Thus prepared, they were covered directly with gold and analyzed on SEM for assessment of marginal seal. When the SEM analysis was completed, the teeth were included into epoxy blocks and cut longitudinally on three slices for each cavity. An assessment of microleakage on stereomicroscope followed. Results were statistically analyzed. For marginal seal evaluation: F.Ultimate and F.Silorane differ statistically with more excellent results than SonicFill for marginal adaptation to the gingival margin, located entirely in the dentin. For microleakage evaluation: F.Ultimate and F.Silorane differ statistically with less microleakage than SonicFill. Based on the results obtained: a strong correlation is found between excellent results for marginal adaptation to the marginal gingival ridge and micropermeability at the direction to the axial wall. We observe a more significant influence of time at the gingival margin of the cavities. There is a significant increase in the presence of marginal fissures (p = 0.001). A significant impact of time (p < 0.000) and of the material (p < 0.000) was found in the analysis of the microleakage.

Download Full-text

Effect of Shortened Light-Curing Modes on Bulk-Fill Resin Composites

Operative Dentistry ◽

10.2341/19-101-l ◽

2020 ◽

Vol 45 (5) ◽

pp. 496-505

Author(s):

CS Sampaio ◽

PG Pizarro ◽

PJ Atria ◽

R Hirata ◽

M Giannini ◽

...

Keyword(s):

Tensile Strength ◽

Bond Strength ◽

Shear Bond Strength ◽

Light Output ◽

High Mode ◽

Resin Composites ◽

Curing Time ◽

Micro Computed Tomography ◽

Polymerization Shrinkage ◽

Light Curing

Clinical Relevance Shortened light curing does not affect volumetric polymerization shrinkage or cohesive tensile strength but negatively affects the shear bond strength of some bulk-fill resin composites. When performing shortened light curing, clinicians should be aware of the light output of their light-curing units. SUMMARY Purpose: To evaluate volumetric polymerization shrinkage (VPS), shear bond strength (SBS) to dentin, and cohesive tensile strength (CTS) of bulk-fill resin composites (BFRCs) light activated by different modes. Methods and Materials: Six groups were evaluated: Tetric EvoCeram bulk fill + high mode (10 seconds; TEC H10), Tetric EvoFlow bulk fill + high mode (TEF H10), experimental bulk fill + high mode (TEE H10), Tetric EvoCeram bulk fill + turbo mode (five seconds; TEC T5), Tetric EvoFlow bulk fill + turbo mode (TEF T5), and experimental bulk fill + turbo mode (TEE T5). Bluephase Style 20i and Adhese Universal Vivapen were used for all groups. All BFRC samples were built up on human molar bur-prepared occlusal cavities. VPS% and location were evaluated through micro–computed tomography. SBS and CTS tests were performed 24 hours after storage or after 5000 thermal cycles; fracture mode was analyzed for SBS. Results: Both TEC H10 and TEE H10 presented lower VPS% than TEF H10. However, no significant differences were observed with the turbo-curing mode. No differences were observed for the same BFRC within curing modes. Occlusal shrinkage was mostly observed. Regarding SBS, thermal cycling (TC) affected all groups. Without TC, all groups showed higher SBS values for high mode than turbo mode, while with TC, only TEC showed decreased SBS from high mode to turbo modes; modes of fracture were predominantly adhesive. For CTS, TC affected all groups except TEE H10. In general, no differences were observed between groups when comparing the curing modes. Conclusions: Increased light output with a shortened curing time did not jeopardize the VPS and SBS properties of the BFRCs, although a decreased SBS was observed in some groups. TEE generally showed similar or improved values for the tested properties in a shortened light-curing time. The VPS was mostly affected by the materials tested, whereas the SBS was affected by the materials, curing modes, and TC. The CTS was not affected by the curing modes.

Download Full-text

The Silorane-based Resin Composites: A Review

Operative Dentistry ◽

10.2341/15-311-lit ◽

2017 ◽

Vol 42 (1) ◽

pp. E24-E34 ◽

Cited By ~ 9

Author(s):

GA Maghaireh ◽

NA Taha ◽

H Alzraikat

Keyword(s):

Mechanical Properties ◽

Bond Strength ◽

Clinical Significance ◽

Physical And Mechanical Properties ◽

Marginal Adaptation ◽

Resin Composites ◽

Restorative Material ◽

Polymerization Shrinkage ◽

Tooth Structure

SUMMARY This article aims to review the research done on the silorane-based resin composites (SBRC) regarding polymerization shrinkage and contraction stresses and their ability to improve the shortcomings of the methacrylate-based resin composites (MRBC). Special attention is given to their physical and mechanical properties, bond strength, marginal adaptation, and cusp deflection. The clinical significance of this material is critically appraised with a focus on the ability of SBRC to strengthen the tooth structure as a direct restorative material. A search of English peer-reviewed dental literature (2003-2015) from PubMed and MEDLINE databases was conducted with the terms “low shrinkage” and “silorane composites.” The list was screened, and 70 articles that were relevant to the objectives of this work were included.

Download Full-text

Polymerization shrinkage-stress kinetics of resin-composites

Dental Materials ◽

10.1016/j.dental.2014.08.115 ◽

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

Download Full-text

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

Operative Dentistry ◽

10.2341/13-017-l ◽

2014 ◽

Vol 39 (4) ◽

pp. 374-382 ◽

Cited By ~ 127

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.

Download Full-text

Effect of modulated photo-activation on polymerization shrinkage behavior of dental restorative resin composites

European Journal Of Oral Sciences ◽

10.1111/eos.12139 ◽

2014 ◽

Vol 122 (4) ◽

pp. 293-302 ◽

Cited By ~ 39

Author(s):

Tobias T. Tauböck ◽

Albert J. Feilzer ◽

Wolfgang Buchalla ◽

Cornelis J. Kleverlaan ◽

Ivo Krejci ◽

...

Keyword(s):

Resin Composites ◽

Polymerization Shrinkage ◽

Dental Restorative ◽

Shrinkage Behavior

Download Full-text

Does Layering Minimize Shrinkage Stresses in Composite Restorations?

Journal of Dental Research ◽

10.1177/154405910308201206 ◽

2003 ◽

Vol 82 (12) ◽

pp. 967-971 ◽

Cited By ~ 34

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.

Download Full-text