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.

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 Polywave And Monowave Light-Curing Units Effects On Polymerization Efficiency Of Different Photoinitiators

2021 ◽  
Vol 24 (4) ◽  
Author(s):  
Peterson Oliveira Boeira ◽  
Mateus De Azevedo Kinalski ◽  
Mateus Bertolini Fernandes dos Santos ◽  
Rafael Ratto de Moraes ◽  
Giana Silveira Lima
Keyword(s):  
Phosphine Oxide ◽  
Second Generation ◽  
Degree Of Conversion ◽  
Polymerization Reaction ◽  
Third Generation ◽  
Test Results ◽  
Vis Spectroscopy ◽  
Light Curing ◽  
Post Hoc ◽  
High Degree

Objective: of this study was to characterize and correlate the absorption spectra of three photoinitiators [camphorquinone (CQ), diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TPO) and phenylbis (2,4,6-trimethylbenzoyl)-phosphine oxide (BAPO)], using second or third-generation light curing units (LCU), and to evaluate the degree of conversion and the physical properties of an experimental resin adhesive.  Material and methods: Second-generation (Radii-cal® and Emitter D®) and third-generation (Valo® Cordless and Bluephase N®) LCU were assessed regarding spectrum and irradiance rate of emitted light. Also, the photoinitiators (CQ, TPO and BAPO) were characterized by a light absorption spectrum assessed by UV-Vis spectroscopy, degree of conversion and yellowing effect. Statistical analyzes considered two-way ANOVA and post-hoc Tukey test.  Results: BAPO presented higher reactivity compared to TPO. Regarding degree of conversion of the photoinitiators activated by different light-curing units, the Emitter D® device promoted a high degree of conversion. BAPO presented the highest yellowing effect values. Conclusions: The emission and absorption characteristics of the photoinitiators were different. The polymerization reaction activated by the second-generation light-curing unit was reduced when using an experimental resin with photoinitiator TPO, and the third-generation light-curing unit showed a higher polymerization potential regardless of the photoinitiator. Keywords Light-curing of dental adhesives;  Photoinitiators dental; Curing lights dental.

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 The influence of delayed light curing on the degree of conversion and polymerization contraction stress in dual-cured resin luting agents

2017 ◽  
Vol 32 (5) ◽  
pp. 516-526
Author(s):  
Nawaf Labban ◽  
Mounir Iskandar ◽  
Jeffrey A. Platt ◽  
Carl J. Andres ◽  
John A. Levon ◽  
...  
Keyword(s):  
Degree Of Conversion ◽  
Luting Agents ◽  
Light Curing ◽  
Contraction Stress

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.

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.

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

2018 ◽  
Vol 43 (6) ◽  
pp. E280-E287 ◽  
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&lt;0.001) and exposure duration (p&lt;0.001) significantly affected temperature and DC. All groups showed higher DCs with increased exposure times (p&lt;0.05), but there were no statistically significant differences between the groups irradiated with 1000 mW/cm2 and 1500 mW/cm2 (p&gt;0.05). Higher-intensity irradiances yielded higher temperatures (p&lt;0.05), but exposure time did not affect temperature when materials were irradiated at 500 mW/cm2 (p&gt;0.05).

scholarly journals Evaluation of the influence of light-curing units on the degree of conversion in depth of a bulk-fill resin

2020 ◽  
pp. e1117-e1123
Author(s):  
F. Tsuzuki ◽  
L. de Castro-Hoshino ◽  
L. Lopes ◽  
F. Sato ◽  
M. Baesso ◽  
...  
Keyword(s):  
Degree Of Conversion ◽  
Light Curing
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