How light irradiance and curing time affect monomer conversion in light-cured resin composites

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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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.

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Characterization of Experimental Short-Fiber-Reinforced Dual-Cure Core Build-Up Resin Composites

Polymers ◽

10.3390/polym13142281 ◽

2021 ◽

Vol 13 (14) ◽

pp. 2281

Author(s):

Eija Säilynoja ◽

Sufyan Garoushi ◽

Pekka K. Vallittu ◽

Lippo Lassila

Keyword(s):

Fracture Toughness ◽

Resin Composite ◽

Rotating Disk ◽

Monomer Conversion ◽

Short Fiber ◽

Flexural Properties ◽

Resin Composites ◽

Fiber Reinforced ◽

Three Point Bending ◽

Light Curing

As a core build-up material, dual-cured (DC) resin-based composites are becoming popular. The aim of this research was to investigate specific physical and handling properties of new experimental short-fiber-reinforced DC resin composites (SFRCs) in comparison to different commercial, conventional DC materials (e.g., Gradia Core, Rebilda DC, LuxaCore Z, and Visalys® CemCore). Degree of monomer conversion (DC%) was determined by FTIR-spectrometry using either self- or light-curing mode. The flexural strength, modulus, and fracture toughness were calculated through a three-point bending setup. Viscosity was analyzed at room (22 °C) and mouth (35 °C) temperatures with a rotating disk rheometer. The surface microstructure of each resin composite was examined with scanning electron microscopy (SEM). Data were statistically analyzed with analysis of variance ANOVA (p = 0.05). The curing mode showed significant (p < 0.05) effect on the DC% and flexural properties of tested DC resin composites and differences were material dependent. SFRC exhibited the highest fracture toughness (2.3 MPa m1/2) values and LuxaCore showed the lowest values (1 MPa m1/2) among the tested materials (p < 0.05). After light curing, Gradia Core and SFRCs showed the highest flexural properties (p < 0.05), while the other resin composites had comparable values. The novel DC short-fiber-reinforced core build-up resin composite demonstrated super fracture toughness compared to the tested DC conventional resin composites.

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Monomer conversion, microhardness, internal marginal adaptation, and shrinkage stress of bulk-fill resin composites

Dental Materials ◽

10.1016/j.dental.2015.10.001 ◽

2015 ◽

Vol 31 (12) ◽

pp. 1542-1551 ◽

Cited By ~ 81

Author(s):

Bruna Marin Fronza ◽

Frederick Allen Rueggeberg ◽

Roberto Ruggiero Braga ◽

Borys Mogilevych ◽

Luis Eduardo Silva Soares ◽

...

Keyword(s):

Monomer Conversion ◽

Shrinkage Stress ◽

Marginal Adaptation ◽

Resin Composites

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Pre-heating of high-viscosity bulk-fill resin composites: Effects on shrinkage force and monomer conversion

Journal of Dentistry ◽

10.1016/j.jdent.2015.07.014 ◽

2015 ◽

Vol 43 (11) ◽

pp. 1358-1364 ◽

Cited By ~ 36

Author(s):

Tobias T. Tauböck ◽

Zrinka Tarle ◽

Danijela Marovic ◽

Thomas Attin

Keyword(s):

Monomer Conversion ◽

High Viscosity ◽

Resin Composites ◽

Shrinkage Force

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The effects of extended curing time and radiant energy on microhardness and temperature rise of conventional and bulk-fill resin composites

Clinical Oral Investigations ◽

10.1007/s00784-019-02807-1 ◽

2019 ◽

Vol 23 (10) ◽

pp. 3777-3788 ◽

Cited By ~ 3

Author(s):

Matej Par ◽

Igor Repusic ◽

Hrvoje Skenderovic ◽

Ognjen Milat ◽

Jelena Spajic ◽

...

Keyword(s):

Temperature Rise ◽

Radiant Energy ◽

Resin Composites ◽

Curing Time

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The Effect of Different Curing Time Regimens on Immediate Postpolymerization Color Changes of Resin Composites

The Journal of Contemporary Dental Practice ◽

10.5005/jp-journals-10024-1171 ◽

2012 ◽

Vol 13 (4) ◽

pp. 472-475 ◽

Cited By ~ 1

Author(s):

Arash Poorsattar Bejeh Mir ◽

Morvarid Poorsattar Bejeh Mir

Keyword(s):

Color Change ◽

Central Zone ◽

Resin Composites ◽

Curing Time ◽

Tooth Color ◽

System Equation ◽

Color Changes ◽

Light Curing ◽

Color Alteration ◽

Clinically Significant

ABSTRACT Aim Light curing of resin composites may considerably change the color of resin composites. The aim of this study was to evaluate the changing pattern of resin composite's color by different curing times. Materials and methods Fifteen, 1 mm-thick, samples of each A2 shade Clearfill and Filtek P60 composites were prepared. First five samples were cured for 10s (400 mW/cm2) in each pole of the rectangular samples (right upper, right lower, left lower, left upper plus central zone). Consecutive sets of samples, each consists of five, were irradiated by doubling and tripling the curing time to 20 and 30s. Color change were measured by means of CIE 1976 L*a*b system equation (ΔE) for each digitalized picture of the corresponding sample. Results Color of samples was clinically significant changed by increasing the curing time from 10 to 20s and from 20 to 30s for Clearfil (ΔE = 13.86 and 14.11 respectively,) and Filtek P60 (ΔE = 7.68 and 11.66 respectively). The ‘b’ component change was responsible for the most color alteration confirmed by the linear regression model (p < 0.001). Conclusion This study revealed the contrasting pattern of resin composite's color change with the different curing times. Our findings support that light curing is accompanied by a higher attained blue chroma and diminished yellowness of resin composites. Clinical significance A complete and proper curing of sample resin composites on buccal surface of particular tooth, as a common practice to ensure the maximize concordance composite and tooth color, is reassured according to the considerable differences of undercured and overcured in comparison to normocured composite. How to cite this article Poorsattar Bejeh Mir A, Poorsattar Bejeh Mir M. The Effect of Different Curing Time Regimens on Immediate Postpolymerization Color Changes of Resin Composites. J Contemp Dent Pract 2012;13(4):472-475.

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Effect of light-curing time on light-cure/post-cure volumetric polymerization shrinkage and regional ultimate tensile strength at different depths of bulk-fill resin composites

Dental Materials Journal ◽

10.4012/dmj.2018-279 ◽

2019 ◽

Vol 38 (4) ◽

pp. 621-629

Author(s):

Kurumi IDE ◽

Masatoshi NAKAJIMA ◽

Juri HAYASHI ◽

Keiichi HOSAKA ◽

Masaomi IKEDA ◽

...

Keyword(s):

Tensile Strength ◽

Ultimate Tensile Strength ◽

Resin Composites ◽

Curing Time ◽

Polymerization Shrinkage ◽

Light Curing ◽

Different Depths ◽

Effect Of Light

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Evaluation of Two Resin Composites Having Different Matrix Compositions

Dentistry Journal ◽

10.3390/dj8030076 ◽

2020 ◽

Vol 8 (3) ◽

pp. 76

Author(s):

Tarek M. Elshazly ◽

Christoph Bourauel ◽

Dalia I. Sherief ◽

Dalia I. El-Korashy

Keyword(s):

Vickers Microhardness ◽

Resin Composite ◽

Blue Dye ◽

Resin Composites ◽

Methylene Blue Dye ◽

Curing Time ◽

Micro Computed Tomography ◽

Time Data ◽

Polymerization Shrinkage ◽

Dye Penetration

This study compared two resin composites with similar filler systems and different matrix compositions. The depth of cure (DoC), polymerization shrinkage, and marginal leakage were evaluated. A Filtek Bulk Fill resin composite (FB) and a Filtek Supreme resin composite (FS) were used. For the DoC and polymerization shrinkage, cylindrical specimens with different thicknesses were prepared. The DoC was attributed to the bottom/top ratios of Vickers microhardness numbers. For polymerization shrinkage, each specimen was firstly scanned using micro-computed tomography (µCT) then cured for 20 s, then for 10 s, and then for 10 s, and they were rescanned between each curing time. Data were processed using the Mimics software. For marginal leakage, standardized 5 mm cavities were prepared in 90 molars. After etching and bonding, materials were packed according to groups: FB-bulk, FB-incremental, and FS-incremental, which were cured for 20, 30, and 40 s, respectively. After thermo-cycling, teeth were stored in 1% methylene blue dye for 24 h and then sectioned and observed for dye penetration. The results showed insignificant differences in the shrinkage and leakage between the different packing techniques and curing times of both materials. In conclusion, the introduction of a novel matrix into resin composite composition enabled bulk-filling in one layer up to 5 mm deep while keeping a tolerable polymerization shrinkage.

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