scholarly journals Effects of Light Curing Method and Exposure Time on Mechanical Properties of Resin Based Dental Materials

2008 ◽  
Vol 02 (01) ◽  
pp. 37-42 ◽  
Author(s):  
A. Rıza Alpöz ◽  
Fahinur Ertuḡrul ◽  
Dilsah Cogulu ◽  
Aslı Topaloḡlu Ak ◽  
Metin Tanoḡlu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Light Source ◽  
Exposure Time ◽  
Resin Composite ◽  
Dental Materials ◽  
Glass Ionomer Cement ◽  
Curing Time ◽  
Uniform Size ◽  
Halogen Light ◽  
Light Curing

ABSTRACTObjectives: The aim of this study was to investigate microhardness and compressive strength of composite resin (Tetric-Ceram, Ivoclar Vivadent), compomer (Compoglass, Ivoclar, Vivadent), and resin modified glass ionomer cement (Fuji II LC, GC Corp) polymerized using halogen light (Optilux 501, Demetron, Kerr) and LED (Bluephase C5, Ivoclar Vivadent) for different curing times.Methods: Samples were placed in disc shaped plastic molds with uniform size of 5 mm diameter and 2 mm in thickness for surface microhardness test and placed in a diameter of 4 mm and a length of 2 mm teflon cylinders for compressive strength test. For each subgroup, 20 samples for microhardness (n=180) and 5 samples for compressive strength were prepared (n=45). In group 1, samples were polymerized using halogen light source for 40 seconds; in group 2 and 3 samples were polymerized using LED light source for 20 seconds and 40 seconds respectively. All data were analyzed by two way analysis of ANOVA and Tukey’s post-hoc tests.Results: Same exposure time of 40 seconds with a low intensity LED was found similar or more efficient than a high intensity halogen light unit (P>.05), however application of LED for 20 seconds was found less efficient than 40 seconds curing time (P=.03).Conclusions: It is important to increase the light curing time and use appropriate light curing devices to polymerize resin composite in deep cavities to maximize the hardness and compressive strength of restorative materials. (Eur J Dent 2008;2:37-42)

scholarly journals Effect of Light-Sources and Thicknesses of Composite Onlays on Micro-Hardness of Luting Composites

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6849
Author(s):  
Francesco De Angelis ◽  
Mirco Vadini ◽  
Mario Capogreco ◽  
Camillo D’Arcangelo ◽  
Maurizio D’Amario
Keyword(s):  
High Power ◽  
Resin Composite ◽  
Composite Layer ◽  
Resin Cement ◽  
Specimen Thickness ◽  
Light Sources ◽  
Curing Time ◽  
Resin Cements ◽  
Halogen Light ◽  
Light Curing

The aim of this study was to compare three different light-curing-units (LCUs) and determine their effectiveness in the adhesive cementation of indirect composite restorations when a light-curing resin cement is used. Two resin composites were selected: Enamel Plus HRI (Micerium) and AURA (SDI). Three thicknesses (3 mm, 4 mm and 5 mm) were produced and applied as overlays and underlays for each resin composite. A standardized composite layer was placed between underlay and overlay surfaces. Light curing of the resin-based luting composites was attained through the overlay filters using LCUs for different exposure times. All specimens were allocated to experimental groups according to the overlay thickness, curing unit and curing time. Vickers Hardness (VH) notches were carried out on each specimen. Data were statistically evaluated. The curing unit, curing time and overlay thickness were significant factors capable of influencing VH values. The results showed significantly decreased VH values with increasing specimen thickness (p < 0.05). Significant differences in VH values were found amongst the LCUs for the various exposure times (p < 0.05). According to the results, a time of cure shorter than 80 s (with a conventional quartz–tungsten–halogen LCU) or shorter than 40 s (with a high-power light-emitting diode (LED) LCU) is not recommended. The only subgroup achieving clinically acceptable VH values after a short 20 s curing time included the 3 mm-thick overlays made out of the AURA composite, when the high-power LED LCU unit was used (VH 51.0). Composite thickness has an intense effect on polymerization. In clinical practice, light-cured resin cements may result in insufficient polymerization for high thickness and inadequate times. High-intensity curing lights can attain the sufficient polymerization of resin cements through overlays in a significantly shorter time than conventional halogen light.

scholarly journals Influence of the Light Source and Curing Parameters on Microhardness of a Silorane-Based Dental Composite Material

2016 ◽  
Vol 61 (3) ◽  
pp. 1331-1336
Author(s):  
P. Malara ◽  
Z. Czech ◽  
W. Świderski
Keyword(s):  
Composite Material ◽  
Light Source ◽  
Limited Range ◽  
Dental Composite ◽  
Dental Material ◽  
Curing Time ◽  
Led Light ◽  
Halogen Light ◽  
Light Curing ◽  
Microhardness Tester

Abstract The aim of the study was to determine the influence of the light source and the light-curing parameters (the distance of the material from the light source and time of light-curing) on microhardness of Flitek Silorane dental composite material. Standardized samples of Filtek Silorane material were cured using two types of Light Curing Units (LCUs) – halogen and LED. The distance of the light source and time of curing differed between samples. The Knoop’s microhardness was tested using microhardness tester Micromet 5103. Using LED light curing unit allowed to achieve significantly higher microhardness of silorane-based dental material Filtek Silorane than using halogen light curing unit. Decreasing the distance from the light source to the surface of silorane-based material Filtek Silorane improved its microhardness. A prolonged curing time could compensate the drop in microhardness of Filtek Silorane material resulting from an increased distance from the light source to the surface of the material only in a limited range of intervals.

scholarly journals Influence of Prolonged Light-curing Time on the Shear Bonding Strength of Resin to Bleached Enamel

2010 ◽  
Vol 35 (6) ◽  
pp. 672-681 ◽  
Author(s):  
M. Hussain ◽  
Y. Wang
Keyword(s):  
Exposure Time ◽  
Bonding Strength ◽  
Clinical Relevance ◽  
Light Exposure ◽  
Light Emitting Diode ◽  
Resin Composite ◽  
Curing Time ◽  
Light Emitting ◽  
Light Curing ◽  
Shear Bonding Strength

Clinical Relevance The bonding strength of resin composite to bleached enamel can be enhanced by increasing the light exposure time of light-emitting diode units if bonding is delayed for 24 hours.

scholarly journals Compressive strength of esthetic restorative materials polymerized with quartz-tungsten-halogen light and blue LED

2009 ◽  
Vol 20 (1) ◽  
pp. 54-57 ◽  
Author(s):  
Cecy Martins Silva ◽  
Katia Regina Hostilio Cervantes Dias
Keyword(s):  
Compressive Strength ◽  
Light Source ◽  
Composite Resin ◽  
Light Emitting Diode ◽  
Testing Machine ◽  
Quartz Tungsten Halogen ◽  
Halogen Light ◽  
Significant Difference ◽  
Restorative Materials ◽  
Light Curing

This study compared the compressive strength of a composite resin and compomer photoactivated with a conventional quartz-tungsten halogen-light (XL 3000, 3M/SPE) and a blue light-emitting diode (LED) (SmartLite PS; Dentsply/De Trey). Forty disc-shaped specimens were prepared using a split polytetrafluoroethylene matrix (4.0 mm diameter x 8.0 mm hight) in which the materials were inserted incrementally. The curing time of each increment was of 40 s with the QTH and 10 s with the LED. The specimens were randomly assigned to 4 groups (n=10), according to the light source and the restorative material. After storage in distilled water at 37oC ± 2oC for 24 h, the specimens was tested in compressive strength in a universal testing machine with load cell of 500 kgf running at a crosshead speed of 0.5 mm/min. Data (in MPa) were analyzed statistically by ANOVA and Student-Newman-Keuls test (p<0.05). For the composite resin, light curing with the QTH source did not produce statistically significant difference (p>0.05) in the compressive strength when compared to light curing with the LED source. However, light curing of the compomer with the QTH source resulted in significantly higher compressive strength than the use of the LED unit (p>0.05). The composite resin presented significantly higher (p>0.05) compressive strength than the compomer, regardless of the light source. In conclusion, the compressive strength of the tested materials photoactivated with a QTH and a LED light source was influenced by the energy density employed and the chemical composition of the esthetic restorative materials.

scholarly journals Effects of ionizing radiation on surface properties of current restorative dental materials

2021 ◽  
Vol 32 (6) ◽  
Author(s):  
Débora Michelle Gonçalves de Amorim ◽  
Aretha Heitor Veríssimo ◽  
Anne Kaline Claudino Ribeiro ◽  
Rodrigo Othávio de Assunção e Souza ◽  
Isauremi Vieira de Assunção ◽  
...  
Keyword(s):  
Ionizing Radiation ◽  
Surface Properties ◽  
Resin Composite ◽  
Dental Materials ◽  
Glass Ionomer Cement ◽  
Contact Angles ◽  
Glass Ionomer ◽  
Post Radiation ◽  
Restorative Dental Materials ◽  
Ionomer Cement

AbstractTo investigate the impact of radiotherapy on surface properties of restorative dental materials. A conventional resin composite—CRC (Aura Enamel), a bulk-fill resin composite—BFRC (Aura Bulk-fill), a conventional glass ionomer cement—CGIC (Riva self cure), and a resin-modified glass ionomer cement—RMGIC (Riva light cure) were tested. Forty disc-shaped samples from each material (8 mm diameter × 2 mm thickness) (n = 10) were produced according to manufacturer directions and then stored in water distilled for 24 h. Surface wettability (water contact angle), Vickers microhardness, and micromorphology through scanning electron microscopy (SEM) before and after exposition to ionizing radiation (60 Gy) were obtained. The data were statistically evaluated using the two-way ANOVA and Tukey posthoc test (p < 0.05). Baseline and post-radiation values of contact angles were statistically similar for CRC, BFRC, and RMGIC, whilst post-radiation values of contact angles were statistically lower than baseline ones for CGIC. Exposition to ionizing radiation statistically increased the microhardness of CRC, and statistically decreased the microhardness of CGIC. The surface micromorphology of all materials was changed post-radiation. Exposure to ionizing radiation negatively affected the conventional glass ionomer tested, while did not alter or improved surface properties testing of the resin composites and the resin-modified glass ionomer cement tested.

Comparison of Composite Curing Parameters: Effects of Light Source and Curing Mode on Conversion, Temperature Rise and Polymerization Shrinkage

10.2341/05-15 ◽  
2006 ◽  
Vol 31 (2) ◽  
pp. 219-226 ◽  
Author(s):  
Z. Tarle ◽  
A. Knezevic ◽  
N. Demoli ◽  
A. Meniga ◽  
J. Sutalo ◽  
...  
Keyword(s):  
Light Source ◽  
Temperature Rise ◽  
Thermal Injury ◽  
Resin Composite ◽  
Marginal Adaptation ◽  
Low Intensity ◽  
Halogen Light ◽  
Lower Temperature ◽  
Final Degree ◽  
Conversion Temperature

Clinical Relevance The use of a low intensity light source for photopolymerization based on LED technology provides equivalent final degree conversion with possible flow of the resin composite, similar to when QTH technology is used. At the same time, the lower temperature rise in the sample and the more favorable development of shrinkage kinetics compared to the higher intensities of halogen light may aid in maintaining marginal adaptation while avoiding possible thermal injury.

Methods for Hyperspectral Microscope Calibration and Spectra Normalization from Images of Bacteria Cells

2018 ◽  
Vol 61 (2) ◽  
pp. 438-448 ◽  
Author(s):  
Matthew B. Eady ◽  
Bosoon Park ◽  
Seung-Chul Yoon ◽  
Mark A. Haidekker ◽  
Kurt C. Lawrence
Keyword(s):  
Single Cell ◽  
Spectral Data ◽  
Light Source ◽  
Exposure Time ◽  
Scatter Correction ◽  
Peak Shift ◽  
Cellular Level ◽  
Tunable Filter ◽  
Radiometric Calibration ◽  
Halogen Light

Abstract. Hyperspectral microscope images (HMIs) have previously shown promise as a means for rapid and early detection of foodborne bacteria at the cellular level. System calibration and data normalization are critical for comparing information obtained from HMIs collected with multiple instruments and system parameters. Here, we implement a wavelength and radiometric calibration for spectral data obtained from a hyperspectral microscope, assess the spatial uniformity of HMIs, and show the need to normalize data from single-cell regions of interest (ROIs). A hyperspectral microscope with a tungsten halogen light source, acousto-optical tunable filter, and electron multiplying camera with variable gain and exposure time settings were used. HMIs were collected at additional gain settings of 0%, 1.6%, 3.5%, and 5.1% along with ten exposure time settings between 100 and 1000 ms with both calibration lamps. Wavelength peak shift started to occur at an exposure time of 600 ms for 1.6% gain, at 400 ms for 3.5% gain, and at 200 ms for 5.1% gain. HMIs of , Typhimurium, and cells were collected to assess spectral data normalcy and the need for preprocessing spectra from single bacteria cells. Spatial characteristics of cells were assessed by HMIs of a glass slide with a micrometer for determining pixel size from the field of view. HMIs were preprocessed by normalizing cell spectra to the light source and applying multiplicative scatter correction. Data normalcy was assessed on both the raw and preprocessed data sets. Preprocessing the data was found to reduce the cell-to-cell variation associated with a single-cell ROI method, while outliers were detected and verified through HMIs as physically different from other cells. Keywords: Bacteria, Calibration, Food safety, Hyperspectral microscope, Pathogen.

scholarly journals Water sorption of resin-modified glass-ionomer cements photoactivated with LED

2006 ◽  
Vol 20 (4) ◽  
pp. 342-346 ◽  
Author(s):  
Daniela Francisca Gigo Cefaly ◽  
Linda Wang ◽  
Liliam Lucia Carrara Paes de Mello ◽  
Janaína Lima dos Santos ◽  
Jean Rodrigo dos Santos ◽  
...  
Keyword(s):  
Water Sorption ◽  
Resin Composite ◽  
Composite Resins ◽  
Glass Ionomer Cements ◽  
Glass Ionomer ◽  
Constant Mass ◽  
Light Emitting ◽  
Halogen Light ◽  
Resin Modified Glass Ionomer ◽  
Light Curing

The Light Emitting Diodes (LED) technology has been used to photoactivate composite resins and there is a great number of published studies in this area. However, there are no studies regarding resin-modified glass-ionomer cements (RMGIC), which also need photoactivation. Therefore, the aim of this study was to evaluate water sorption of two RMGIC photoactivated with LED and to compare this property to that obtained with a halogen light curing unit. A resin composite was used as control. Five specimens of 15.0 mm in diameter x 1.0 mm in height were prepared for each combination of material (Fuji II LC Improved, Vitremer, and Filtek Z250) and curing unit (Radii and Optilight Plus) and transferred to desiccators until a constant mass was obtained. Then the specimens were immersed into deionized water for 7 days, weighed and reconditioned to a constant mass in desiccators. Water sorption was calculated based on weight and volume of specimens. The data were analyzed by two-way ANOVA and Tukey test (p < 0.05). Specimens photocured with LED presented significantly more water sorption than those photocured with halogen light. The RMGIC absorbed statistically significant more water than the resin composite. The type of light curing unit affected water sorption characteristics of the RMGIC.

Effect of Light Activation of Pulp-Capping Materials and Resin Composite on Dentin Deformation and the Pulp Temperature Change

2018 ◽  
Vol 43 (1) ◽  
pp. 71-80 ◽  
Author(s):  
CJ Soares ◽  
MS Ferreira ◽  
AA Bicalho ◽  
M de Paula Rodrigues ◽  
SSL Braga ◽  
...  
Keyword(s):  
Resin Composite ◽  
Glass Ionomer Cement ◽  
Adhesive System ◽  
Polymerization Temperature ◽  
Micro Ct ◽  
Light Activation ◽  
Pulp Chamber ◽  
Pulp Capping ◽  
Light Curing ◽  
Composite Restoration

SUMMARY Objectives: To analyze the effect of pulp-capping materials and resin composite light activation on strain and temperature development in the pulp and on the interfacial integrity at the pulpal floor/pulp-capping materials in large molar class II cavities. Methods: Forty extracted molars received large mesio-occlusal-distal (MOD) cavity bur preparation with 1.0 mm of dentin remaining at the pulp floor. Four pulp-capping materials (self-etching adhesive system, Clearfil SE Bond [CLE], Kuraray), two light-curing calcium hydroxide cements (BioCal [BIO], Biodinâmica, and Ultra-Blend Plus [ULT], Ultradent), and a resin-modified glass ionomer cement– (Vitrebond [VIT], 3M ESPE) were applied on the pulpal floor. The cavities were incrementally restored with resin composite (Filtek Z350 XT, 3M ESPE). Thermocouple (n=10) and strain gauge (n=10) were placed inside the pulp chamber in contact with the top of the pulpal floor to detect temperature changes and dentin strain during light curing of the pulp-capping materials and during resin composite restoration. Exotherm was calculated by subtracting postcure from polymerization temperature (n=10). Interface integrity at the pulpal floor was investigated using micro-CT (SkyScan 1272, Bruker). The degree of cure of capping materials was calculated using the Fourier transform infrared and attenuated total reflectance cell. Data were analyzed using one-way analysis of variance followed by the Tukey test (α=0.05). Results: Pulpal dentin strains (μs) during light curing of CLE were higher than for other pulp-capping materials (p&lt;0.001). During resin composite light activation, the pulpal dentin strain increased for ULT, VIT, and CLE and decreased for BIO. The pulpal dentin strain was significantly higher during pulp-capping light activation. The temperature inside the pulp chamber increased approximately 3.5°C after light curing the pulp-capping materials and approximately 2.1°C after final restoration. Pulp-capping material type had no influence temperature increase. The micro-CT showed perfect interfacial integrity after restoration for CLE and ULT; however, gaps were found between BIO and pulpal floor in all specimens. BIO had a significantly lower degree of conversion than ULT, VIT, and CLE. Conclusions: Light curing of pulp-capping materials caused deformation of pulpal dentin and increased pulpal temperature in large MOD cavities. Shrinkage of the resin composite restoration caused debonding of BIO from the pulpal floor.

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