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

2002 ◽  
Vol 63 (6) ◽  
pp. 729-738 ◽  
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

Effectiveness of Second-generation Light-emitting Diode (LED) Light Curing Units

2007 ◽  
Vol 8 (2) ◽  
pp. 35-42 ◽  
Author(s):  
Fabrício Aulo Ogliari ◽  
Ulisses Bastos Campregher ◽  
Susana Maria Werner Samuel ◽  
Carmen Beatriz Borges Fortes ◽  
Alberth David Correa Medina ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Second Generation ◽  
Light Emitting Diode ◽  
Strength Properties ◽  
Knoop Hardness ◽  
Curing Time ◽  
Light Emitting ◽  
Led Light ◽  
Three Samples ◽  
Light Curing

Abstract Aim The purpose of this study was to evaluate the effectiveness of three commercially available light emitting diode (LED) light curing units (LCU) (Elipar FreeLight - 3M ESPE; UltraLume LED2 - Ultradent; and Single V - BioArt) for polymerizing Z250-A3 composite (3M ESPE) using Knoop hardness, polymerization depth, and flexural strength properties. Methods and Materials The XL 2500 (3M ESPE) LCU, which is a conventional halogen unit, was used as a control. In all cases the curing time was 20 seconds. Hardness was determined 24 hours after composite cure for 10 samples of 8 mm diameter and 2 mm height for each LCU tested. Samples were stored dry in a lightproof container prior to testing. The depth of cure of the composite was measured immediately after composite polymerization for each LCU using three samples 4 mm in diameter and 6 mm in height. Flexural strength was determined for five samples 24 hours after immersion in distilled water at 37°C. Each sample measured 25 mm in length, 2 mm in width, and 2 mm in height for each LCU tested. Conclusion The results were treated statistically for comparison of the LCUs. In all cases the results obtained by LED LCUs were not different or were higher than a conventional halogen LCU. Clinical Significance Second generation LED LCUs were as effective as/or more effective than a halogen LCU for polymerization of the used composite. The present study shows second generation LEDs have the potential to replace halogen LCUs. Citation Campregher UB, Samuel SMW, Fortes CBB, Medina ADC, Collares FMC, Ogliari FA. Effectiveness of Second-generation Light-emitting Diode (LED) Light Curing Units. J Contemp Dent Pract 2007 February;(8)2:035-042.

scholarly journals Analysis of the Effect of Dental Chair Light on the Knoop Hardness of Composite Resin While Light Curing with QTH and LED Light Units

2012 ◽  
Vol 3 (2) ◽  
pp. 156-160
Author(s):  
Bandish Parekh ◽  
Sucheta Sathe
Keyword(s):  
Composite Resin ◽  
Light Emitting Diode ◽  
Hardness Test ◽  
Knoop Hardness ◽  
Degree Of Polymerization ◽  
Led Light ◽  
Group Iii ◽  
Dental Chair ◽  
Group I ◽  
Light Curing

ABSTRACT Dental chair lights have been known to rapidly polymerize lightcured composites beyond the point of workability. Often in our dental clinics we are advised to switch off the dental chair light while light curing of dental composites. The purpose of this study was to determine whether the dental chair light causes any effect on the degree of polymerization of light cured composites using the quartz tungsten halogen (QTH) and the light emitting diode (LED) light curing units (LCUs). Filtek Z350 composite samples of 2 × 5 mm were prepared in an acrylic mold. Four groups were made having 20 samples each. In group I and II light curing was done using QTH LCU with and without the dental chair light respectively. Similarly in group III and IV LED LCU was used. Microhardness was measured and compared using Knoop's hardness Test. Data was submitted to ANOVA and Tukey's test. Results showed that the average microhardness was significantly higher in group 4 (LED light curing with dental chair light on). Thus, it was concluded that the dental chair light can be left on while using QTH and LED LCU's during light curing of composite material. How to cite this article Parekh B, Sathe S, Hegde V. Analysis of the Effect of Dental Chair Light on the Knoop Hardness of Composite Resin While Light Curing with QTH and LED Light Units. World J Dent 2012;3(2):156-160.

Halogen and LED light curing of composite: temperature increase and Knoop hardness

2006 ◽  
Vol 10 (1) ◽  
pp. 66-71 ◽  
Author(s):  
L. F. Schneider ◽  
S. Consani ◽  
L. Correr-Sobrinho ◽  
A. B. Correr ◽  
M. A. Sinhoreti
Keyword(s):  
Temperature Increase ◽  
Knoop Hardness ◽  
Led Light ◽  
Light Curing

Photoinitiator dependent composite depth of cure and Knoop hardness with halogen and LED light curing units

Biomaterials ◽  
2003 ◽  
Vol 24 (10) ◽  
pp. 1787-1795 ◽  
Author(s):  
Alexander Uhl ◽  
Robin W. Mills ◽  
Klaus D. Jandt
Keyword(s):  
Knoop Hardness ◽  
Led Light ◽  
Depth Of Cure ◽  
Light Curing

scholarly journals Does an additional UV LED improve the degree of conversion and Knoop Hardness of light-shade composite resins?

2012 ◽  
Vol 06 (04) ◽  
pp. 396-401 ◽  
Author(s):  
Maria Cecília Caldas Giorgi ◽  
Flávio Henrique Baggio Aguiar ◽  
Luís Luís Soares ◽  
Airton Abrahão Martin ◽  
Priscila Christiane Suzy Liporoni ◽  
...  
Keyword(s):  
Knoop Hardness ◽  
Surface Interaction ◽  
Composite Resins ◽  
Degree Of Conversion ◽  
Third Generation ◽  
Composite Surface ◽  
Led Light ◽  
Uv Led ◽  
Significant Difference ◽  
Light Curing

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)

scholarly journals A Comparative Evaluation of Curing Depth and Compressive Strength of Dental Composite Cured with Halogen Light Curing Unit and Blue Light Emitting Diode: An in vitro Study

2012 ◽  
Vol 13 (6) ◽  
pp. 834-837 ◽  
Author(s):  
R Divyashree ◽  
M Gururaj ◽  
CN Vijaya Kumar ◽  
Joseph Paul ◽  
L Krishnaprasada
Keyword(s):  
Compressive Strength ◽  
Light Emitting Diode ◽  
Dental Composite ◽  
Light Emitting ◽  
Led Light ◽  
Group I ◽  
Halogen Light ◽  
Light Curing ◽  
Group B

ABSTRACT Purpose To evaluate the curing depth and compressive strength of dental composite using halogen light curing unit and light emitting diode light curing unit. Materials and methods Eighty cylindrical composite specimens were prepared using posterior composite P60(3M). Forty specimens, out of which 20 samples (group A) cured with halogen light and 20 samples (group B) cured using light emitting diode (LED) light were checked for curing depth according to ISO 4049. Remaining 40 samples out of which 20 samples (group I) cured using halogen light and 20 samples (group II) cured using LED light were checked for compressive strength using Instron universal testing machine. Results Twenty samples (group A) cured with halogen light showed better curing depth than 20 samples (group B) cured with LED light. Twenty samples (group I) cured with halogen light showed almost similar results as 20 samples (group II) cured with LED light for compressive strength. Conclusion Halogen light commonly used to cure composite resin have greater depth of cure, when compared to LED light, while both the lights produced compressive strength which is almost similar. Clinical significance Lower depth of cure with the LED unit, compared to the QTH unit, is associated with different light scattering due to differences in spectral emission. LED technology differs from QTH by the spectral emission that favorably matches the absorption spectrum of camphorquinone. How to cite this article Kumar CNV, Gururaj M, Paul J, Krishnaprasada L, Divyashree R. A Comparative Evaluation of Curing Depth and Compressive Strength of Dental Composite cured with Halogen Light Curing Unit and Blue Light Emitting Diode: An in vitro Study. J Contemp Dent Pract 2012;13(6):834-837.

scholarly journals Depth of cure of dental composites submitted to different light-curing modes

2006 ◽  
Vol 14 (2) ◽  
pp. 71-76 ◽  
Author(s):  
Raphael Vieira Monte Alto ◽  
José Guilherme Antunes Guimarães ◽  
Laiza Tatiana Poskus ◽  
Eduardo Moreira da Silva
Keyword(s):  
Original Data ◽  
Knoop Hardness ◽  
Dental Composites ◽  
Depth Of Cure ◽  
Soft Start ◽  
Composites Materials ◽  
Light Curing ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

OBJECTIVE: This study evaluated the depth of cure of five dental composites submitted to different light-curing modes. MATERIAL AND METHODS: Canal-shaped cavities with 5mm of length were prepared on the buccal surfaces of extracted third molars, and restored using P-60, A-110, Admira, Z-250 and Supreme resin composites. Materials were light-cured from the top, according to three modes (Group 1- Conventional (C): 500 mW/cm² / 40 s; Group 2 - Soft-Start (SS): 250 mW/cm²/ 20 s + 500 mW/cm²/ 20 s + 500 mW/cm²/ 10 s and Group 3 - LED: 250 mW/cm²/ 40 s). After that, cavity longitudinal surfaces were polished and marked with a millimeter scale of 4mm of length. Depth of cure was evaluated by means of Knoop hardness number (KHN), so that five indentations were performed at each millimeter. Original data were submitted to three-way ANOVA and Fisher's LSD test (alpha = 0.01). RESULTS: All materials presented a significant reduction on KHN from first to third millimeter. Regarding depth of cure, the results obtained for Conventional and Soft-Start modes were similar, but statistically superiors to those found for group 3 (LED). CONCLUSION: This performance may be related to the differences among energy densities obtained with different light-curing modes.

Effect of LED Light-Curing Spectral Emission Profile on Light-Cured Resin Cement Degree of Conversion

2020 ◽  
Author(s):  
RQ Ramos ◽  
RR Moraes ◽  
GC Lopes
Keyword(s):  
Clinical Relevance ◽  
Degree Of Conversion ◽  
Resin Cement ◽  
Light Activation ◽  
Spectral Emission ◽  
Led Light ◽  
Emission Profile ◽  
Light Curing

Clinical Relevance The use of multipeak LED light-curing guarantees efficiency on light activation of Ivocerin-containing light-cured resin cement.

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

Polymers ◽  
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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