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 Effect of different light sources on degree of conversion, hardness and plasticization of a composite

2013 ◽  
Vol 1 (2) ◽  
pp. 134
Author(s):  
Bruno de Castro Ferreira Barreto ◽  
Anderson Catelan ◽  
Ricardo Coelho Okida ◽  
Gisele Fernanda Gonçalves ◽  
Gisele Rodrigues da Silva ◽  
...  
Keyword(s):  
Clinical Performance ◽  
Light Emitting Diode ◽  
Knoop Hardness ◽  
Composite Resins ◽  
Degree Of Conversion ◽  
Light Sources ◽  
Light Emitting ◽  
Quartz Tungsten Halogen ◽  
Light Curing ◽  
Ft Ir

Clinical performance of composite resins depends largely on their mechanical properties, and those are influenced by several factors, such as the light-curing mode. The purpose of this study was to evaluate the influence of different light sources on degree of conversion (DC), Knoop hardness (KHN) and plasticization (P) of a composite resin. Disc-shaped specimens (5 x 2 mm) of Esthet-X (Dentsply) methacrylate-based microhybrid composite were light-cured using quartz-tungsten-halogen (QTH) Optilight Plus (Gnatus) or light-emitting diode (LED) Ultraled (Dabi Atlante) curing units at 400 and 340 mW/cm2 of irradiance, respectively. After 24 h, absorption spectra of composite were obtained using Nexus 670 (Nicolet) FT-IR spectrometer in order to calculate the DC. The KHN was measured in the HMV-2000 (Shimadzu) microhardness tester under 50 g loads for 15 s, and P was evaluated by percentage reduction of hardness after 24 h of alcohol storage. Data were subjected to t-Student test (alpha = 0.05). QTH device showed lower P and higher KHN than LED (p < 0.05), and no difference between the light-curing units was found for DC (p > 0.05). The halogen-curing unit with higher irradiance promoted higher KHN and lower softening in alcohol than LED.

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

2017 ◽  
Vol 28 (5) ◽  
pp. 632-637 ◽  
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.

scholarly journals Effects of radiant exposure values using second and third generation light curing units on the degree of conversion of a lucirin-based resin composite

2017 ◽  
Vol 25 (2) ◽  
pp. 140-146 ◽  
Author(s):  
Kelly Antonieta Oliveira Rodrigues de Faria CARDOSO ◽  
Driellen Christine ZARPELLON ◽  
Camila Ferreira Leite MADRUGA ◽  
José Augusto RODRIGUES ◽  
Cesar Augusto Galvão ARRAIS
Keyword(s):  
Resin Composite ◽  
Degree Of Conversion ◽  
Third Generation ◽  
Radiant Exposure ◽  
Light Curing

scholarly journals Effects of delivering the same radiant exposures at 730, 1450, and 2920 mW/cm2 to two resin-based composites

2017 ◽  
Vol 11 (01) ◽  
pp. 022-028 ◽  
Author(s):  
Maan M. AlShaafi
Keyword(s):  
Fourier Transform ◽  
Degree Of Conversion ◽  
Attenuated Total Reflectance ◽  
Curing Time ◽  
Total Reflectance ◽  
Metal Rings ◽  
Significant Difference ◽  
Light Curing ◽  
Knoop Microhardness ◽  
Different Depths

ABSTRACT Objective: To evaluate the effects of curing two resin-based composites (RBC) with the same radiant exposures at 730, 1450, and 2920 mW/cm2. Materials and Methods: Two types of RBC, Filtek Supreme Ultra and Tetric-EvoCeram-Bulk Fill, were light-cured to deliver the same radiant exposures for 5, 10, or 20 s by means of a modified Valo light emitted diode light-curing unit with the light tip placed directly over each specimen. The RBC was expressed into metal rings that were 2.0 and 4.0 mm in thickness, directly on an attenuated total reflectance Fourier transform infrared plate heated to 33°C, and the degree of conversion (DC) of the RBC was recorded. The specimens were then removed and the Knoop microhardness (KHN) was tested at both the bottom and the top of each specimen. The KHN was tested again after 24 h and 7 days of storage in the dark at 37°C and 100% humidity. The DC and KHN results were analyzed with Fisher's protected least significant difference at α = 0.05. Results: The DC values for the specimens cured at the three different irradiance levels were similar. However, at different depths, there were differences in the DC values. In general, there were no clear differences among the samples cured in the three different groups, and the KHN was always greater 24 h and 7 days later (P < 0.05). Conclusions: Despite the curing time, and as long as the samples were cured with the same radiant exposures, there were no significant effects on the DC and KHN of both RBCs.

scholarly journals Comparison of two curing protocols during adhesive cementation: can the step luting technique supersede the traditional one?

Odontology ◽  
2020 ◽  
Author(s):  
Vincenzo Tosco ◽  
Riccardo Monterubbianesi ◽  
Giulia Orilisi ◽  
Simona Sabbatini ◽  
Carla Conti ◽  
...  
Keyword(s):  
Degree Of Conversion ◽  
Third Generation ◽  
Luting Agents ◽  
Light Curing ◽  
Adhesive Cementation ◽  
Removal Of Cement ◽  
Time Point

Abstract This study aims to compare the degree of conversion of two different curing protocols used during adhesive cementation. The following resin luting agents were tested: Hri Flow (MF) and pre-heated Hri Micerium (MH); light-cure Nexus Third Generation (NX3L) and dual-cure Nexus Third Generation (NX3D); dual cured RelyX Ultimate (RXU) and light-cure RelyX Veneers (RXL). For each tested material, ten samples were prepared and divided into two groups which had different curing protocols (P1 and P2): in P1, samples were cured for 40 s; in P2, samples were cured for 5 s, and then, after 20 s, cured again for additional 40 s. The degree of conversion (DC) was evaluated both during the first 5 min of the curing phase and after 1, 2, 7, 14 and 28 days (p = 0.05). Different trends were observed in DC values after 5 min by comparing P1 and P2. In both P1 and P2, DC decreased as follows, MH > MF > NX3L > RXL > RXU > NX3D. There were significant differences of DC values among all resin luting agents (p < 0.05) in P1, while no significant differences existed between MH and MF, and NX3L and RXL in P2. At 1, 2, 7, 14 and 28 days the light curing luting agents had a higher DC than the dual luting agents (p < 0.05). P1 and P2 were not statistically different at each time point (p > 0.05). Both P1 and P2 protocols let achieve an acceptable DC after 28 days. The tested P2 can be safely used to lute indirect restorations, simplifying the removal of cement excesses.

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.

Sign in / Sign up

Export Citation Format

Share Document