Depth-dependence of Degree of Conversion and Microhardness for Dual-cure and Light-cure Composites

2019 ◽  
Vol 45 (4) ◽  
pp. 396-406 ◽  
Author(s):  
R Wang ◽  
Y Wang
Keyword(s):  
Room Temperature ◽  
Degree Of Conversion ◽  
Light Irradiation ◽  
Surface Microhardness ◽  
Raman Spectroscopic ◽  
Micro Raman Spectroscopy ◽  
Test Conditions ◽  
Significant Difference ◽  
Entire Depth ◽  
Different Depths

Clinical Relevance New dual-cure bulk-fill composites show promise for uniform degree of conversion and microhardness throughout the entire depth of direct restorations. SUMMARY Objective: The aim of this study was to evaluate the degree of conversion (DC) through micro-Raman spectroscopy and surface microhardness in Vickers hardness (VHN) of three new dual-cure bulk-fill resin-based composites (RBCs) compared with light-cure bulk-fill and incremental RBCs at two clinically relevant depths and for two light irradiation times. Methods: Three commercially available restorative dual-cure bulk-fill RBCs (BulkEZ, HyperFIL, and Injectafil) were evaluated and compared with three light-cure RBCs (Filtek Bulk Fill Flowable, Filtek One Bulk Fill, and incremental Filtek Z250) as controls. Specimens were prepared in two different depths (0.5 mm and 5 mm) and were light irradiated for 20 seconds or 40 seconds. Self-cure was also evaluated for the three dual-cure bulk-fill RBCs. Micro-Raman spectroscopic measurements and VHN tests (n=5) were made after 24 hours of dry storage in the dark at room temperature for all test conditions. Data were analyzed using one-way and two-way analyses of variance (α=0.05). Results: All tested RBCs showed significantly higher DC and VHN values at 0.5-mm depth than at 5-mm depth, with the exception of BulkEZ, which showed similar DC and VHN values at two depths. The three dual-cure bulk-fill RBCs showed significantly higher DC than the three light-cure RBCs under the same curing condition. The three dual-cure RBCs showed much smaller differences in VHN values between the two depths than the three light-cure RBCs. Twenty seconds and 40 seconds of light irradiation did not generate significant difference in DC and VHN values for the three dual-cure bulk-fill RBCs at either depth or for the three light-cure RBCs at the 0.5-mm depth; however, 40 seconds of light irradiation generated significantly higher DC and VHN values for One Bulk Fill and Z250 at the 5-mm depth compared with 20 seconds of light irradiation.

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 Effects of Different Temperatures and Storage Time on the Degree of Conversion and Microhardness of Resin-based Composites

2016 ◽  
Vol 17 (3) ◽  
pp. 217-223 ◽  
Author(s):  
Maan M AlShaafi
Keyword(s):  
Room Temperature ◽  
Storage Time ◽  
Light Emitting Diode ◽  
Dental Materials ◽  
Degree Of Conversion ◽  
Curing Temperature ◽  
Significant Difference ◽  
Different Temperatures ◽  
And Storage ◽  
Made In

ABSTRACT Objective Dental materials are often made at room temperature, whereas clinically they are made in the mouth. This study evaluated the effects of temperature on the degree of conversion (DC) and Knoop microhardness (KHN). Materials and methods Two types of resin-based composites (RBCs) were light-cured using a light-emitting diode (LED) lightcuring unit. The resin specimens were centered on an Attenuated Total Reflectance Fourier transform infrared (FT-IR) plate heated to 23°C or 33°C. The DC of the resin was calculated after 120 seconds, the specimens were removed, and the KHN was tested at the bottom of the specimens both immediately, after 24 hours, and after 7 days storage in distilled water in complete darkness at 37°C. The effects of different temperatures on the DC and KHN with their storage time were compared by analysis of variance and Fisher's protected least significant difference post hoc multiple comparison tests (p < 0.05). Results Increasing the temperature had a significant and positive effect on the DC and KHN for immediate values of the RBCs. Greater conversion and hardness occurred when the curing temperature was increased from 23°C to 33°C. The KHN increased significantly after 24 hours of storage. There was a linear relationship between DC and KHN (R2 = 0.86) within the range of DC and KHN studied. Conclusion The physical properties of dental materials can be expected to be better when made in the mouth than when they are made in a laboratory at room temperature. How to cite this article AlShaafi MM. Effects of Different Temperatures and Storage Time on the Degree of Conversion and Microhardness of Resin-based Composites. J Contemp Dent Pract 2016;17(3):217-223.

Degree of Conversion of Luting Resins Around Ceramic Inlays in Natural Deep Cavities: A Micro-Raman Spectroscopy Analysis

2010 ◽  
Vol 35 (5) ◽  
pp. 579-586 ◽  
Author(s):  
U. Lohbauer ◽  
M. Pelka ◽  
R. Belli ◽  
J. Schmitt ◽  
E. Mocker ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Clinical Relevance ◽  
Degree Of Conversion ◽  
Spectroscopy Analysis ◽  
Previous Evidence ◽  
Micro Raman Spectroscopy ◽  
Ceramic Inlays ◽  
Different Depths ◽  
Deep Cavities ◽  
Luting Resins

Clinical Relevance Contrary to previous evidence, the degrees of conversion of resin luting materials have been shown to reach statistically similar values in three different depths around ceramic inlays luted to natural cavities. Both dual-cure and light-cure materials have presented conversion homogeneity, although they have been shown to be material-dependent.

Tyrosine-Selective Bioconjugation with Iminoxyl Radicals

2020 ◽  
Author(s):  
Katsuya Maruyama ◽  
Takashi Ishiyama ◽  
Yohei Seki ◽  
Kounosuke Oisaki ◽  
Motomu Kanai
Keyword(s):  
Reaction Time ◽  
Steric Hindrance ◽  
Room Temperature ◽  
Water Soluble ◽  
Light Irradiation ◽  
Sodium Ascorbate ◽  
Iminoxyl Radical ◽  
Short Reaction Time ◽  
Modified Peptides ◽  
The Stability

A novel Tyr-selective protein bioconjugation using the water-soluble persistent iminoxyl radical is described. The conjugation proceeded with high Tyr-selectivity and short reaction time under biocompatible conditions (room temperature in buffered media under air). The stability of the conjugates was tunable depending on the steric hindrance of iminoxyl. The presence of sodium ascorbate and/or light irradiation promoted traceless deconjugation, restoring the native Tyr structure. The method is applied to the synthesis of a protein-dye conjugate and further derivatization to azobenzene-modified peptides.

scholarly journals Integrated Bimodal Fitting for Unilateral CI Users with Residual Contralateral Hearing

2021 ◽  
Vol 11 (2) ◽  
pp. 200-206
Author(s):  
Gennaro Auletta ◽  
Annamaria Franzè ◽  
Carla Laria ◽  
Carmine Piccolo ◽  
Carmine Papa ◽  
...  
Keyword(s):  
Cochlear Implants ◽  
Hearing Aids ◽  
Speech Intelligibility ◽  
Hearing Aid ◽  
Performance Difference ◽  
Test Conditions ◽  
Significant Difference ◽  
Noisy Conditions ◽  
New Formula ◽  
Better Than

Background: The aim of this study was to compare, in users of bimodal cochlear implants, the performance obtained using their own hearing aids (adjusted with the standard NAL-NL1 fitting formula) with the performance using the Phonak Naìda Link Ultra Power hearing aid adjusted with both NAL-NL1 and a new bimodal system (Adaptive Phonak Digital Bimodal (APDB)) developed by Advanced Bionics and Phonak Corporations. Methods: Eleven bimodal users (Naìda CI Q70 + contralateral hearing aid) were enrolled in our study. The users’ own hearing aids were replaced with the Phonak Naìda Link Ultra Power and fitted following the new formula. Speech intelligibility was assessed in quiet and noisy conditions, and comparisons were made with the results obtained with the users’ previous hearing aids and with the Naída Link hearing aids fitted with the NAL-NL1 generic prescription formula. Results: Using Phonak Naìda Link Ultra Power hearing aids with the Adaptive Phonak Digital Bimodal fitting formula, performance was significantly better than that with the users’ own rehabilitation systems, especially in challenging hearing situations for all analyzed subjects. Conclusions: Speech intelligibility tests in quiet settings did not reveal a significant difference in performance between the new fitting formula and NAL-NL1 fittings (using the Naída Link hearing aids), whereas the performance difference between the two fittings was very significant in noisy test conditions.

In2S3/BiOI composites boost visible-light photocatalytic degradation of tetracycline hydrochloride

CrystEngComm ◽  
2021 ◽  
Author(s):  
Panbing Hu ◽  
Yanmei Xin ◽  
Congfei Yao ◽  
Yuqing Miao
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Visible Light Irradiation ◽  
Room Temperature ◽  
Light Irradiation ◽  
Tetracycline Hydrochloride ◽  
Structure And Morphology ◽  
Morphology Characterization ◽  
Visible Light Photocatalytic

The In2S3/BiOI composites were synthesized at room temperature which significantly improved the photocatalytic degradation performance of tetracycline hydrochloride (TC) under visible light irradiation. Structure and morphology characterization have been performed...

CsOH and its Lighter Homologues – a Comparison

2014 ◽  
Vol 69 (11-12) ◽  
pp. 1229-1236
Author(s):  
Matthias Wörsching ◽  
Constantin Hoch
Keyword(s):  
Gas Phase ◽  
Room Temperature ◽  
Structure Type ◽  
Alkali Metal Hydroxide ◽  
X Ray ◽  
Raman Spectroscopic ◽  
Cesium Hydroxide ◽  
Free Ion ◽  
The One ◽  
First Time

Abstract Cesium hydroxide, CsOH, was for the first time characterised on the basis of single-crystal data. The structure is isotypic to the one of the room-temperature modification of NaOH and can be derived from the NaCl structure type thus allowing the comparison of all alkali metal hydroxide structures. Raman spectroscopic investigations show the hydroxide anion to behave almost as a free ion as in the gas phase. The X-ray investigations indicate possible H atom positions.

Study on formaldehyde gas-sensing of In2O3-sensitized ZnO nanoflowers under visible light irradiation at room temperature

2012 ◽  
Vol 22 (25) ◽  
pp. 12915 ◽  
Author(s):  
Lina Han ◽  
Dejun Wang ◽  
Jiabao Cui ◽  
Liping Chen ◽  
Tengfei Jiang ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Room Temperature ◽  
Gas Sensing ◽  
Light Irradiation
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