Degree of conversion of resin-based orthodontic bonding materials cured with single-wave or dual-wave LED light-curing units

ABSTRACTObjective: The purpose of this study was to evaluate the degree of conversion (DC) using FTRaman spectroscopy and the Knoop hardness (KHN) of composites cured by second and third-generation LED light curing-units (LCU), Radii Cal and Ultralume 5.Methods: Three composites (Filtek Supreme XT, Filtek Z350, and Esthet X) were selected for this study. KHN testing (n=10) was performed with 10 indentations for the top (T) and bottom (B) surfaces. For DC (n=10), both the T and B surfaces were analyzed.Results: For KHN, the three composites differed in hardens. There was a “LCU-surface” interaction, in which Radii Cal showed significantly greater hardens in the B surface. For DC, there was a “composite-surface-LCU” interaction. For the “composite” factor, there was no significant difference between the groups, except for Supreme XT-Radii Cal (T or B surfaces). For the “LCU” factor there was a significant difference for Supreme XT T surface, Ultralume 5 obtained a higher DC. For the Z350 T surface, a significant difference in the DC in which Radii Cal obtained better results. For the “surface” factor, all groups presented T surfaces with a higher DC than the B surfaces, the sole exceptions involved Esthet X-Radii Cal and Z350-Ultralume 5.Conclusion: Knowledge regarding composite composition and the characteristics of LCUs are important for effective polymerization. (Eur J Dent 2012;6:396-401)

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Degree of conversion of resin-based materials cured with dual-peak or single-peak LED light-curing units

International Journal of Paediatric Dentistry ◽

10.1111/ipd.12104 ◽

2014 ◽

Vol 25 (2) ◽

pp. 93-102 ◽

Cited By ~ 8

Author(s):

Siobhan M. Lucey ◽

Ario Santini ◽

Elizabeth M. Roebuck

Keyword(s):

Degree Of Conversion ◽

Single Peak ◽

Led Light ◽

Light Curing

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The Photoinitiators Used in Resin Based Dental Composite—A Review and Future Perspectives

Polymers ◽

10.3390/polym13030470 ◽

2021 ◽

Vol 13 (3) ◽

pp. 470

Author(s):

Andrea Kowalska ◽

Jerzy Sokolowski ◽

Kinga Bociong

Keyword(s):

Current Knowledge ◽

Biomechanical Properties ◽

Degree Of Conversion ◽

Dental Composite ◽

Polymerization Process ◽

Dental Composites ◽

Dental Resin ◽

Dental Resins ◽

Light Curing

The presented paper concerns current knowledge of commercial and alternative photoinitiator systems used in dentistry. It discusses alternative and commercial photoinitiators and focuses on mechanisms of polymerization process, in vitro measurement methods and factors influencing the degree of conversion and hardness of dental resins. PubMed, Academia.edu, Google Scholar, Elsevier, ResearchGate and Mendeley, analysis from 1985 to 2020 were searched electronically with appropriate keywords. Over 60 articles were chosen based on relevance to this review. Dental light-cured composites are the most common filling used in dentistry, but every photoinitiator system requires proper light-curing system with suitable spectrum of light. Alternation of photoinitiator might cause changing the values of biomechanical properties such as: degree of conversion, hardness, biocompatibility. This review contains comparison of biomechanical properties of dental composites including different photosensitizers among other: camphorquinone, phenanthrenequinone, benzophenone and 1-phenyl-1,2 propanedione, trimethylbenzoyl-diphenylphosphine oxide, benzoyl peroxide. The major aim of this article was to point out alternative photoinitiators which would compensate the disadvantages of camphorquinone such as: yellow staining or poor biocompatibility and also would have mechanical properties as satisfactory as camphorquinone. Research showed there is not an adequate photoinitiator which can be as sufficient as camphorquinone (CQ), but alternative photosensitizers like: benzoyl germanium or novel acylphosphine oxide photoinitiators used synergistically with CQ are able to improve aesthetic properties and degree of conversion of dental resin.

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Knoop hardness depth profiles and compressive strength of selected dental composites polymerized with halogen and LED light curing technologies

Journal of Biomedical Materials Research ◽

10.1002/jbm.10390 ◽

2002 ◽

Vol 63 (6) ◽

pp. 729-738 ◽

Cited By ~ 44

Author(s):

Alexander Uhl ◽

Robin W. Mills ◽

Richard W. Vowles ◽

Klaus D. Jandt

Keyword(s):

Compressive Strength ◽

Knoop Hardness ◽

Dental Composites ◽

Led Light ◽

Depth Profiles ◽

Light Curing ◽

Hardness Depth

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Light curing through glass ceramics with a second- and a third-generation LED curing unit: effect of curing mode on the degree of conversion of dual-curing resin cements

Clinical Oral Investigations ◽

10.1007/s00784-013-0924-4 ◽

2013 ◽

Vol 17 (9) ◽

pp. 2127-2137 ◽

Cited By ~ 15

Author(s):

Simon Flury ◽

Adrian Lussi ◽

Reinhard Hickel ◽

Nicoleta Ilie

Keyword(s):

Glass Ceramics ◽

Degree Of Conversion ◽

Third Generation ◽

Resin Cements ◽

Light Curing ◽

Dual Curing

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Impact of Material Shade and Distance from Light Curing Unit Tip on the Depth of Polymerization of Composites

Brazilian Dental Journal ◽

10.1590/0103-6440201701727 ◽

2017 ◽

Vol 28 (5) ◽

pp. 632-637 ◽

Cited By ~ 4

Author(s):

André L. Faria-e-Silva ◽

Christopher Fanger ◽

Lillian Nguyen ◽

Demetri Howerton ◽

Carmem S. Pfeifer

Keyword(s):

Light Transmission ◽

Degree Of Conversion ◽

Experimental Conditions ◽

Composite Surface ◽

Infra Red ◽

Light Curing ◽

Different Depths ◽

The Mean

Abstract This study aimed to evaluate the effect of the composite shade and distance from the light-curing unit (LCU) tip on the irradiance reaching the bottom of composite disks and on the depth of polymerization. Composites of three shades (opaque - OXDC, bleach - BXL, and A2) were inserted into molds with 3-mm of thickness positioned over a spectrometer and photo-activated with the LCU (Bluephase) tip placed at 0 or 1 cm from the composite surface. The mean irradiance reaching the bottom of composite was recorded during the entire photo-activation (30 s). Specimens (2 x 2 x 4 mm) were polymerized and used to map the degree of conversion achieved in different depths from irradiated surface. Specimens were sectioned into slices that were positioned over the platform of the infra-red microscope connected to the spectrometer to map the conversion. The conversion was measured in eight different depths every 500-µm. Increasing the distance of LCU tip reduced the irradiance only for A2. Interposing OXDC disks resulted in lowest values of irradiance and A2 the highest one. A tendency to decrease the conversion was observed towards the bottom of specimens for all experimental conditions, and the slope was more accentuated for OXDC. Differences among shades and distances from LCU tip were evident only beyond 1.5-2.0 mm of depth. In conclusion, both composite shade and distance from LCU tip might affect the light-transmission and depth of polymerization, while the effect of last was more pronounced.

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Effect of Irradiance and Exposure Duration on Temperature and Degree of Conversion of Dual-Cure Resin Cement for Ceramic Restorations

Operative Dentistry ◽

10.2341/17-283-l ◽

2018 ◽

Vol 43 (6) ◽

pp. E280-E287 ◽

Cited By ~ 1

Author(s):

JS Shim ◽

SH Han ◽

N Jha ◽

ST Hwang ◽

W Ahn ◽

...

Keyword(s):

Fourier Transform ◽

Infrared Spectroscopy ◽

Exposure Duration ◽

Near Infrared ◽

Degree Of Conversion ◽

Resin Cement ◽

Resin Cements ◽

Digital Thermometer ◽

Light Curing ◽

Ceramic Restorations

SUMMARY This study investigated the effects of irradiance and exposure duration on dual-cured resin cements irradiated through ceramic restorative materials. A single light-curing unit was calibrated to three different irradiances (500, 1000, and 1500 mW/cm2) and irradiated to three different attenuating materials (transparent acryl, lithium disilicate, zirconia) with 1-mm thicknesses for 20 or 60 seconds. The changes in irradiance and temperature were measured with a radiometer (or digital thermometer) under the attenuating materials. The degree of conversion (DC) of dual-cure resin cement after irradiation at different irradiances and exposure durations was measured with Fourier transform near infrared spectroscopy. Two-way analysis of variance revealed that irradiance (p<0.001) and exposure duration (p<0.001) significantly affected temperature and DC. All groups showed higher DCs with increased exposure times (p<0.05), but there were no statistically significant differences between the groups irradiated with 1000 mW/cm2 and 1500 mW/cm2 (p>0.05). Higher-intensity irradiances yielded higher temperatures (p<0.05), but exposure time did not affect temperature when materials were irradiated at 500 mW/cm2 (p>0.05).

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