The Ability of Dental Practitioners to Light-Cure Simulated Restorations

2021 ◽  
Author(s):  
DD Kojic ◽  
O El-Mowafy ◽  
R Price ◽  
W El-Badrawy
Keyword(s):  
Light Emitting Diode ◽  
Patient Simulator ◽  
Measuring Device ◽  
Light Emitting ◽  
Radiant Exposure ◽  
Paired Samples ◽  
Dental Practitioners ◽  
Dental Offices ◽  
Posterior Restorations ◽  
Dental Professionals

Clinical Relevance Using a patient simulator, dental professionals were tested to determine their ability to light-polymerize simulated restorations in their dental practice. After receiving specific instructions and training using the simulator, their ability to deliver sufficient light to polymerize restorations was significantly and substantially improved. SUMMARY Objectives: To determine the ability of dental professionals to deliver a radiant exposure of at least six J/cm2 in 10 seconds to simulated restorations. Methods and Materials: The study initially examined 113 light-emitting-diode (LED) light polymerization units (LPUs) used in dental offices to determine if they could deliver at least 6 J/cm2 radiant exposure (RE) in 10s. This assessment was completed by using a laboratory-grade light measuring device (checkMARC, BlueLight Analytics, Halifax, NS, Canada). The participating dental professionals whose LPUs could deliver 6 J/cm2 then used their own LPU to light-cure simulated anterior and posterior restorations in the MARC Patient Simulator (BlueLight Analytics). They then received specific instructions and were retested using the same LPUs. Data were statistically analyzed with a series of one-way analysis of variance (ANOVA), two-way ANOVA, paired-samples t-tests, Fisher post hoc multiple comparison tests, and McNemar tests with a preset alpha of 0.05 (SPSS Inc). Results: Ten (8.8%) LPUs could not deliver the required RE to the checkMARC in 10s and were eliminated from the study. For the anterior restoration, most dental practitioners (87.3%) could deliver at least 6 J/cm2 before instructions. After receiving additional light-curing instructions, only two (1.9%) participants were unable to deliver 6 J/cm2 to the anterior location. At the posterior location, only 55.3% (57) participants could deliver at least 6 J/cm2 before the instructions. After receiving these instructions, an additional 32 participants delivered at least 6 J/cm2. Overall, after receiving instructions on how to use the LPU correctly, the participants improved the amount of RE they delivered to anterior and posterior restorations by 22.5% and 30%, respectively. Conclusion: This study revealed that at the baseline, 44.7% of participating dental professionals failed to deliver 6 J/cm2 in 10s to the posterior simulated restoration when using their own LPU.

scholarly journals The Influence of Distance on Radiant Exposure and Degree of Conversion Using Different Light-Emitting-Diode Curing Units

2019 ◽  
Vol 44 (3) ◽  
pp. E133-E144 ◽  
Author(s):  
AO Al-Zain ◽  
GJ Eckert ◽  
JA Platt
Keyword(s):  
Strong Correlation ◽  
Light Emitting Diode ◽  
Pearson Correlation ◽  
Correlation Coefficients ◽  
Degree Of Conversion ◽  
Light Emitting ◽  
Radiant Exposure ◽  
Light Curing ◽  
Irradiance Data ◽  
Resin Curing

SUMMARY Objectives: To investigate the influence of curing distance on the degree of conversion (DC) of a resin-based composite (RBC) when similar radiant exposure was achieved using six different light-curing units (LCUs) and to explore the correlation among irradiance, radiant exposure, and DC. Methods and Materials: A managing accurate resin curing-resin calibrator system was used to collect irradiance data for both top and bottom specimen surfaces with a curing distance of 2 mm and 8 mm while targeting a consistent top surface radiant exposure. Square nanohybrid-dual-photoinitiator RBC specimens (5 × 5 × 2 mm) were cured at each distance (n=6/LCU/distance). Irradiance and DC (micro-Raman spectroscopy) were determined for the top and bottom surfaces. The effect of distance and LCU on irradiance, radiant exposure, and DC as well as their linear associations were analyzed using analysis of variance and Pearson correlation coefficients, respectively (α=0.05). Results: While maintaining a similar radiant exposure, each LCU exhibited distinctive patterns in decreased irradiance and increased curing time. No significant differences in DC values (63.21%-70.28%) were observed between the 2- and 8-mm distances, except for a multiple-emission peak LCU. Significant differences in DC were detected among the LCUs. As expected, irradiance and radiant exposure were significantly lower on the bottom surfaces. However, a strong correlation between irradiance and radiant exposure did not necessarily result in a strong correlation with DC. Conclusions: The RBC exhibited DC values >63% when the top surface radiant exposure was maintained, although the same values were not reached for all lights. A moderate-strong correlation existed among irradiance, radiant exposure, and DC.

scholarly journals Earable POCER: Development of a Point-of-Care Ear Sensor for Respiratory Rate Measurement

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3020 ◽  
Author(s):  
Kazuhiro Taniguchi ◽  
Atsushi Nishikawa
Keyword(s):  
Respiratory Rate ◽  
Light Emitting Diode ◽  
Point Of Care ◽  
Respiratory Frequency ◽  
Infrared Light ◽  
Rate Measurement ◽  
Ear Canal ◽  
Measuring Device ◽  
Light Emitting ◽  
Reflected Light

We have carried out research and development on an earphone-type respiratory rate measuring device, earable POCER. The name earable POCER is a combination of “earable”, which is a word coined from “wearable” and “ear”, and “POCER”, which is an acronym for “point-of-care ear sensor for respiratory rate measurement”. The earable POCER calculates respiratory frequency, based on the measurement values over one minute, through the simple attachment of an ear sensor to one ear of the measured subject and displays these on a tablet terminal. The earable POCER irradiates infrared light using a light-emitting diode (LED) loaded on an ear sensor to the epidermis within the ear canal and, by receiving that reflected light with a phototransistor, it measures movement of the ear canal based on respiration. In an evaluation experiment, eight healthy subjects first breathed through the nose 12 times per minute, then 16 times per minute, and finally 20 times per minute, in accordance with the flashing of a timing instruction LED. The results of these evaluation tests showed that the accuracy of the respiratory frequency was 100% for nose breathing 12 times per minute, 93.8% at 16 times, and 93.8% at 20 times.

Effect of Thickness on Light Transmission and Vickers Hardness of Five Bulk-fill Resin-based Composites Using Polywave and Single-peak Light-emitting Diode Curing Lights

2019 ◽  
Vol 44 (1) ◽  
pp. 96-107 ◽  
Author(s):  
GA Maghaireh ◽  
RB Price ◽  
N Abdo ◽  
NA Taha ◽  
H Alzraikat
Keyword(s):  
Vickers Microhardness ◽  
Light Transmission ◽  
Light Emitting Diode ◽  
Surface Hardness ◽  
Single Peak ◽  
Distilled Water ◽  
Light Emitting ◽  
Radiant Exposure ◽  
Light Curing ◽  
Post Hoc

SUMMARY Objectives: This study compared light transmission through different thicknesses of bulk-fill resin-based composites (RBCs) using a polywave and a single-peak light-emitting diode light-curing unit (LCU). The effect on the surface hardness was also evaluated. Methods: Five bulk-fill RBCs were tested. Specimens (n=5) of 1-, 2-, 4-, or 6-mm thickness were photopolymerized for 10 seconds from the top using a polywave (Bluephase Style) or single–peak (Elipar S10) LCU, while a spectrophotometer monitored in real time the transmitted irradiance and radiant exposure reaching the bottom of the specimen. After 24 hours of storage in distilled water at 37°C, the Vickers microhardness (VH) was measured at top and bottom. Results were analyzed using multiple-way analysis of variance, Tukey post hoc tests, and multivariate analysis (α=0.05). Results: The choice of LCU had no significant effect on the total amount of light transmitted through the five bulk-fill RBCs at each thickness. There was a significant decrease in the amount of light transmitted as the thickness increased for all RBCs tested with both LCUs (p<0.001). Effect of LCU on VH was minimal (ηp2=0.010). The 1-, 2-, and 4-mm-thick specimens of SDR, X-tra Fill, and Filtek Bulk Restorative achieved a VHbottom/top ratio of approximately 80% when either LCU was used. Conclusions: The total amount of light transmitted through the five bulk-fill RBCs was similar at the different thicknesses using either LCU. The polywave LCU used in this study did not enhance the polymerization of the tested bulk-fill RBCs when compared with the single-peak LCU.

scholarly journals Determination of Vitamin C in Foods Using the Iodine-Turbidimetric Method Combined with an Infrared Camera

2020 ◽  
Vol 10 (8) ◽  
pp. 2655 ◽  
Author(s):  
Yi Miao ◽  
Yuanyang Zhu ◽  
Wenzhu Zhao ◽  
Changshuai Jiao ◽  
Hongwei Mo ◽  
...  
Keyword(s):  
Vitamin C ◽  
Light Emitting Diode ◽  
Infrared Camera ◽  
Infrared Light ◽  
Measuring Device ◽  
Light Emitting ◽  
Turbidimetric Method ◽  
Novel Method ◽  
Color Components

A novel method was proposed for the determination of vitamin C (VC) using an infrared camera combined with the iodine-turbidimetric method. Based on the redox between VC and iodine, the residual iodine was measured using the turbidimetric method with an infrared camera to obtain VC content. The light emitted by the infrared light-emitting diode (LED) was absorbed and scattered when it penetrated the residual iodine suspension. The transmitted light was captured by the infrared camera to form a digital image and the responding color components and grayscale values were obtained. The obtained color components and log-grayscale were fitted to the VC concentration, and the fitted relation expressions were used to measure the unknown VC solution. A VC measuring device equipped with an infrared camera and processing software was designed to obtain the color components corresponding to the images of the iodine suspensions. Compared with the spectrophotometry, the method based on the color component of brightness had a higher accuracy for measuring the VC standard solution. For VC measurements in tomatoes, nectarines, and VC tablets, our proposed method was highly consistent with spectrophotometry. Therefore, this method could potentially be implemented in the determination of VC in fruits and tablets, or other foods.

Stability of the Light Output, Oral Cavity Tip Accessibility in Posterior Region and Emission Spectrum of Light-Curing Units

2018 ◽  
Vol 43 (4) ◽  
pp. 398-407 ◽  
Author(s):  
CB André ◽  
G Nima ◽  
M Sebold ◽  
M Giannini ◽  
RB Price
Keyword(s):  
Light Emitting Diode ◽  
Light Output ◽  
Emission Spectra ◽  
Posterior Region ◽  
Light Emitting ◽  
Second Molar ◽  
Radiant Exposure ◽  
Light Curing ◽  
Standard Output ◽  
Lower Irradiance

SUMMARYObjectives: This study evaluated the light output from six light-emitting diode dental curing lights after 25 consecutive light exposures without recharging the battery, tip accessibility in the posterior region, and light beam spread from light-curing units.Methods: Irradiance, spectral peak, and radiant exposure were measured with the battery fully charged (Bluephase Style, ESPE Cordless, Elipar S10, Demi Ultra, Valo Cordless, and Radii-Cal) and monitored for 25 light exposures (each lasting 10 seconds). The tip diameter was measured to identify the beam size and the ability of the six light-curing units to irradiate all areas of the lower second molar in the standard output setting.Results: Four curing lights delivered a single peak wavelength from 454 to 462 nm, and two (Bluephase Style and Valo Cordless) delivered multiple emission peaks (at 410 and 458 nm and 400, 450, and 460 nm, respectively). The irradiance and radiant exposure always decreased after 25 exposures by 2% to 8%, depending on the light unit; however, only ESPE Cordless, Valo Cordless, and Radii-Cal presented a statistical difference between the first and the last exposure. The tip diameter ranged from 6.77 mm to 9.40 mm. The Radii-Cal delivered the lowest radiant exposure and irradiance. This light was also unable to access all the teeth with the tip parallel to the occlusal surface of the tooth.Conclusion: Not all of the blue-emitting lights deliver the same emission spectra, and some curing lights delivered a lower irradiance (as much as 8% lower) after the 25th exposure.

Influence of Irradiance on the Push-out Bond Strength of Composite Restorations Photoactivated by LED

2008 ◽  
Vol 9 (2) ◽  
pp. 89-96 ◽  
Author(s):  
Mário Alexandre Coelho Sinhoreti ◽  
Simonides Consani ◽  
Lourenço Correr-Sobrinho ◽  
Dario Segreto ◽  
William Cunha Brandt
Keyword(s):  
Bond Strength ◽  
Light Emitting Diode ◽  
Testing Machine ◽  
Adhesive System ◽  
Conical Cavity ◽  
Significance Level ◽  
Light Emitting ◽  
Radiant Exposure ◽  
Composite Restorations ◽  
Push Out

Abstract Aim The aim of this study was to compare the bond strength of resin composites to dental structure photoactivated with a light emitting diode (LED) curing unit. Methods and Materials One hundred bovine incisors were selected and a conical cavity was prepared in the facial surface of each tooth. Clearfil SE Bond (Kuraray CO., LTD. Osaka, Japan) adhesive system was applied, and the cavities were filled with a single increment of Filtek™ Z250 (3M ESPE, St. Paul, MN, USA) or Esthet-X (Dentsply-Caulk – Mildford, DE, USA). The specimens were assigned to ten groups (n=10) according to the irradiance used: 100, 200, 300, 400, or 500 mW/cm2. Photoactivation was accomplished using an Ultrablue IS LED (DMC Equipamentos LTDA, São Carlos, SP, Brazil). The radiant exposure time was kept constant. A push-out test was conducted in a universal testing machine. Bond strength values were submitted to a two-way analysis of variance (ANOVA) and a Tukey's test at the 5% significance level. Results The bond strength of the Z250 was higher than the Eshet-X (p<0.05). However, the modulation of irradiance adjusted to the same radiant exposure had no influence on Z250. The bond strength using an irradiance of 100mW/cm2 was higher than the other levels for Esthet-X. When composites were compared, no significant differences were detected between them for activation with irradiances of 100 and 200 mW/cm2. Conclusion The modulation of the luminous energy emitted by LED was almost unable to provide significant differences among the groups for both composites, except for a lower irradiance of Esthet-X. Citation Segreto D, Brandt WC, Correr-Sobrinho L, Sinhoreti MAC, Consani S. Influence of Irradiance on the Push-out Bond Strength of Composite Restorations Photoactivated by LED. J Contemp Dent Pract 2008 February;(9)2:089-096.

scholarly journals Light Transmittance and Depth of Cure of a Bulk Fill Composite Based on the Exposure Reciprocity Law

2021 ◽  
Vol 32 (1) ◽  
pp. 78-84
Author(s):  
Mateus Garcia Rocha ◽  
Jean-François Roulet ◽  
Mario Alexandre Coelho Sinhoreti ◽  
Américo Bortolazzo Correr ◽  
Dayane Oliveira
Keyword(s):  
Wavelength Range ◽  
Light Emitting Diode ◽  
Light Transmittance ◽  
Light Emitting ◽  
Depth Of Cure ◽  
Radiant Exposure ◽  
Reciprocity Law ◽  
Blue Wavelength ◽  
Light Curing ◽  
Microscopy Data

Abstract The objective of this study was to evaluate the effect of the exposure reciprocity law of a multi-wave light-emitting diode (LED) on the light transmittance (LT), depth of cure (DOC) and degree of conversion in-depth (DC) of a bulk fill composite. A bulk fill composite (EvoCeram® bulk fill, Ivoclar Vivadent) was photoactivated using the multi-wave LED (VALO™ Cordless, Ultradent). The LED was previously characterized using a spectrophotometer to standardize the time of exposure when using the Standard or Xtra-Power modes with the same radiant exposure of 20J/cm2. LT was evaluated through samples of the bulk fill composite every millimeter till 4 mm in-depth. DOC was evaluated according to the ISO 4049. DC of the central longitudinal cross-section from each sample of the DOC test was mapped using FT-NIR microscopy. Data were statistically analyzed according to the experimental design (α=0.05; ß=0.2). The radiant exposure in the violet wavelength range for Standard and Xtra-Power was 4.5 and 5.0 J/cm2, respectively; for the blue wavelength range the radiant exposure for Standard and Xtra-Power was 15.5 and 15.0 J/cm2, respectively. There was no statistical difference in the DOC using Standard or Xtra-Power light-curing modes, but the DOC was lower than the claimed by the manufacturer (4 mm). The DC was not significantly affected by the light-curing mode up to 4 mm in depth (p>0.05). According to exposure reciprocity law, the reduction in exposure time using the same radiant exposure did not affect the depth of cure of the bulk fill composite.

scholarly journals Performance of Multiple Light-curing Units used by Dental Students

2020 ◽  
Vol 14 (1) ◽  
pp. 671-680
Author(s):  
Afnan O. Al-Zain ◽  
Ziyad A. Al-Ghamdi ◽  
Mahfouz M. Basahal ◽  
Rozana M. Al-Bukhary ◽  
EliseuAldrighi Münchow
Keyword(s):  
Clinical Setting ◽  
Dental Students ◽  
Dental Student ◽  
Patient Simulator ◽  
Posterior Teeth ◽  
Light Emitting ◽  
Radiant Exposure ◽  
Light Curing ◽  
Resin Curing ◽  
Over Time

Aim: To investigate the performance of multiple Light-curing Units (LCUs) of different manufacturers used in a dental student clinical setting. Background: Manufacturers claim that the irradiance values of the LCUs stay stable over time. However, this may not be accurate among the different units. Objective: This study investigated the performance in terms of the irradiance, radiant exposure, and DOC of multiple LCUs of different types used in a dental student clinical setting. Methods: Four different LCU were investigated (n=5 units/LCU manufacturer): three Light-Emitting-Diodes (LED) units (Demi Ultra, Mini LED, and E-Morlit) and one quartz-tungsten-halogen (QTH) (PolyluxII). Irradiance and radiant exposure were collected [Managing Accurate Resin Curing-Patient Simulator (MARC-PS)](n=5 readings/unit/tooth). Depth of Cure (DOC) was performed (ISO 4049:2009standards) using a micro-hybrid composite (n=5/unit). Data were analyzed using Kruskal-Wallis and ANOVA followed by Student-Newman-Keuls and Tukey post hoc methods, respectively (α=0.05). Results: Using the MARC-PS anterior and posterior teeth sensors, respectively, the mean irradiance for Demi Ultra was (1625.7±38.8) and (1250.4±25.2); Mini LED (1381.1±37.8) and (1058.1±27.3); E-Morlit (1831.1±294.7) and (1545.2±176.0); and Polylux II (932.4±368.5) and (840.4±353.4)mW/cm2. The radiant exposure range was 16-38 J/cm2 for all LCUs. LCUs’ mean DOC ranged from 2.9 to 3.1 mm. Significant differences in irradiance and radiant exposure values were detected among the multiple units and manufacturers. Significant differences in DOC values among the Demi Ultra and Polylux II units were detected. DOC met the standards except for onePolylux II unit. Conclusion: The irradiance and radiant exposure values were not the same among the different units, regardless of the manufacturers’ claim of the irradiance values stability over time. Polymerization was not compromised except for one QTH unit per the DOC measurements. Itis highly recommended to closely monitor LCUs used in dental student clinical areas due to the high demand in this type of setting.

Synchronization of Chaotic Quantum Dot Light Emitting Diodes under Optical Feedback Effect

2020 ◽  
pp. 144-148
Keyword(s):  
Quantum Dot ◽  
Delay Time ◽  
Chaos Synchronization ◽  
Optical Feedback ◽  
Light Emitting Diode ◽  
Feedback Effect ◽  
Complete Synchronization ◽  
Light Emitting ◽  
Coupling Methods ◽  
Coupling Parameters

Chaos synchronization of delayed quantum dot light emitting diode has been studied theortetically which are coupled via the unidirectional and bidirectional. at synchronization of chaotic, The dynamics is identical with delayed optical feedback for those coupling methods. Depending on the coupling parameters and delay time the system exhibits complete synchronization, . Under proper conditions, the receiver quantum dot light emitting diode can be satisfactorily synchronized with the transmitter quantum dot light emitting diode due to the optical feedback effect.

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