scholarly journals Effect of different light curing units on Knoop hardness and temperature of resin composite

2009 ◽  
Vol 20 (3) ◽  
pp. 308
Author(s):  
RicardoDanil Guiraldo ◽  
Simonides Consani ◽  
RafaelLeonardo Xediek Consani ◽  
WilsonBatista Mendes ◽  
Thais Lympius ◽  
...  
Keyword(s):  
Resin Composite ◽  
Knoop Hardness ◽  
Light Curing

scholarly journals Influence of Tip Diameter and Light Spectrum of Curing Units on the Properties of Bulk-Fill Resin Composites

2021 ◽  
Author(s):  
Igor Oliveiros Cardoso ◽  
Alexandre Coelho Machado ◽  
Luísa de Oliveira Fernandes ◽  
Paulo Vinícius Soares ◽  
Luís Henrique Araújo Raposo
Keyword(s):  
Fourier Transform ◽  
Resin Composite ◽  
Knoop Hardness ◽  
Specimen Preparation ◽  
Resin Composites ◽  
Light Spectrum ◽  
Specimen Diameter ◽  
Light Spectra ◽  
Light Curing ◽  
The Fourier Transform

Abstract Objective The aim of this study was to evaluate the influence of different light-curing units (LCUs) with distinct tip diameters and light spectra for activating bulk-fill resins. Materials and Methods The specimens (n = 10) were made from a conventional composite (Amaris, VOCO) and bulk-fill resins (Aura Bulk Fill, SDI; Filtek One, 3M ESPE; Tetric Bulk Fill, Ivoclar Vivadent) with two diameters, 7 or 10 mm, × 2 mm thickness. Following 24 hours of specimen preparation, the degree of conversion (DC) was evaluated using the Fourier-transform infrared unit. Knoop hardness (KHN) readings were performed on the center and periphery of the specimens. Data were assessed for homoscedasticity and submitted to one-way and three-way analysis of variance followed by the Tukey's and Dunnett's tests, depending on the analysis performed (α = 0.05). Results LCUs and specimen diameter significantly affected the DC. The Tetric Bulk Fill provided increased DC results when light-cured with Valo (54.8 and 53.5%, for 7 and 10 mm, respectively) compared with Radii Xpert (52.1 and 52.9%, for 7 and 10 mm, respectively). No significant differences in KHN results were noted for the conventional resin composite (Amaris) compared with LCUs (p = 0.213) or disc diameters (p = 0.587), but the center of the specimen exhibited superior KHN (p ≤ 0.001) than the periphery. Conclusion The light spectrum of the multipeak LCU (Valo) significantly increased the DC and KHN of the bulk-fill resin composite with additional initiator to camphorquinone (Tetric Bulk Fill) compared with the monowave LCU (Radii Xpert). The tip size of the LCUs influenced the performance of some of the resin composites tested.

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 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.

Influence of Ambient Temperature and Light-curing Moment on Polymerization Shrinkage and Strength of Resin Composite Cements

2018 ◽  
Vol 43 (6) ◽  
pp. 619-630 ◽  
Author(s):  
N Rohr ◽  
JA Müller ◽  
J Fischer
Keyword(s):  
Tensile Strength ◽  
Resin Composite ◽  
Indirect Tensile Strength ◽  
Homogeneous Distribution ◽  
Sem Images ◽  
Polymerization Shrinkage ◽  
Ambient Temperatures ◽  
Light Curing ◽  
Indirect Tensile ◽  
Composite Cements

ABSTRACT Objective: The purpose of this study was to establish a clinically appropriate light-curing moment for resin composite cements while achieving the highest indirect tensile strength and lowest polymerization shrinkage. Methods and Materials: Polymerization shrinkage of seven resin composite cements (Multilink Automix, Multilink Speed Cem, RelyX Ultimate, RelyX Unicem 2 Automix, Panavia V5, Panavia SA plus, VITA Adiva F-Cem) was measured at ambient temperatures of 23°C and 37°C. Testing was done for autopolymerized and light-cured specimens after light application at either 1, 5, or 10 minutes after mixing. Indirect tensile strength of all cements was measured after 24 hours of storage at temperatures of 23°C and 37°C, for autopolymerized and light-cured specimens after light application 1, 5, or 10 minutes after mixing. To illustrate filler size and microstructures, SEM images of all cements were captured. Statistical analysis was performed with one-way ANOVA followed by post hoc Fisher LSD test (α=0.05). Results: Final polymerization shrinkage of the resin composite cements ranged from 3.2% to 7.0%. An increase in temperature from 23°C to 37°C as well as the light-curing moment resulted in material dependent effects on the polymerization shrinkage and indirect tensile strength of the cements. Polymerization shrinkage of the cements did not correlate with the indirect tensile strength of the cement in the respective groups. Highest indirect tensile strengths were observed for the materials containing a homogeneous distribution of fillers with a size of about 1 μm (Multilink Automix, Panavia V5, VITA Adiva F-Cem). Conclusion: The magnitude of the effect of light-curing moment and temperature increase on polymerization shrinkage and indirect tensile strength of resin composite cements is material dependent and cannot be generalized.

scholarly journals Irradiance and Radiant Exposures Delivered by LED Light-Curing Units Used by a Left and Right-Handed Operator

2018 ◽  
Vol 29 (3) ◽  
pp. 282-289 ◽  
Author(s):  
Carlos José Soares ◽  
Gabriel Felipe de Bragança ◽  
Renata Afonso da Silva Pereira ◽  
Monise de Paula Rodrigues ◽  
Stella Sueli Lourenço Braga ◽  
...  
Keyword(s):  
Emission Spectrum ◽  
Light Emitting Diode ◽  
Resin Composite ◽  
Emission Spectra ◽  
Hand Preference ◽  
Second Molar ◽  
Left Hand ◽  
Radiant Exposure ◽  
Light Curing ◽  
The Right

Abstract The combination of the restoration location, the hand preference of the operator using the light-curing unit (LCU), and the design of the LCU all can have an impact on the amount of the light delivered to the restoration. To evaluate the effect of left-handed or right-handed users, the position of the operator (dentist or assistant), and the LCU design on the irradiance, radiant exposure and emission spectrum delivered to the same posterior tooth. Two light emitting diode (LED) LCUs were tested: an angulated monowave LCU Radii-Cal (SDI, Victoria, Australia) and a straight aligned multi-peak LCU Valo Cordless (Ultradent, South Jordan, UT, USA). The irradiance values (mW/cm2), radiant exposure (J/cm2) and emission spectrum were measured using a sensor in maxillary left second molar tooth. The irradiance and radiant exposure were analyzed using three-way ANOVA followed by Tukey test (a=0.05). The emission spectra (nm) were analyzed descriptively. The interaction between LCU design, operator position, and hand preference significantly influenced the irradiance and radiant exposure (P<0.001). In all cases, Valo delivered significantly higher irradiance than Radii-Cal. The handedness and the operator position affected the irradiance and radiant exposure delivered from Valo. Operator position and access affect the irradiance and radiant exposure delivered to the maxillary left second molar. The irradiance and radiant exposure can be greater when a right-hand operator is positioned on the right side of the chair and a left-hand operator is positioned on the left side of the chair. This may result in better resin composite polymerization.

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.

Influence of light-curing protocols on polymerization shrinkage and shrinkage force of a dual-cured core build-up resin composite

2010 ◽  
Vol 118 (4) ◽  
pp. 423-429 ◽  
Author(s):  
Tobias T. Tauböck ◽  
Tissiana Bortolotto ◽  
Wolfgang Buchalla ◽  
Thomas Attin ◽  
Ivo Krejci
Keyword(s):  
Resin Composite ◽  
Polymerization Shrinkage ◽  
Shrinkage Force ◽  
Light Curing

scholarly journals Influence of Sealer and Light-Curing Units on Push-Out Bond Strength Of Composite Resin to Weakened Roots

2016 ◽  
Vol 27 (4) ◽  
pp. 430-435 ◽  
Author(s):  
Adriana Corrêa de Lima ◽  
Fuad Jacob Rached-Junior ◽  
Natália Spadini de Faria ◽  
Danielle Cristine Messias ◽  
Carolina de Andrade Lima Chaves ◽  
...  
Keyword(s):  
Bond Strength ◽  
Composite Resin ◽  
Resin Composite ◽  
Laser Scanning Microscopy ◽  
Cervical Region ◽  
Confocal Laser ◽  
Filling Material ◽  
Ah Plus ◽  
Light Curing ◽  
Push Out

Abstract The aim of this study was to assess the influence of sealer and light-curing unit on regional bond strength of resin composite to the weakened roots. Ninety roots of incisors were experimentally weakened, subjected to biomechanical preparation and filled with either Endofill, AH Plus or MTA Fillapex The roots were desobturated e reinforced with resin composite and fiber post light-activated with one of the light sources: halogen at 600 mW/ cm2 (QTH-600), LED at 800 mW/ cm2 (LED-800) and LED at 1500 mW/ cm2 (LED-1500). The roots were sectioned in slices from cervical, middle and apical root-reinforcement regions and analyzed by push out test, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Bond strength data were analyzed using three-way ANOVA and Tukey´s test (α=0.05). Specimens filled with AH Plus had higher bond strength, followed by MTA Fillapex and Endofill (p<0.05). For light-curing unit, LED-1500 presented superior bond strength than LED-800, which was higher than QTH-600 (p<0.05). The cervical region had the greatest mean values (p<0.05) while apical part showed the lowest bond strength (p<0.05). CLMS revealed remaining filling material in the dentinal tubules for all groups. The eugenol-containing sealer (Endofill) compromised the push-out bond strength of composite resin to the root dentin. Bond strength was favored in the cervical region, and when LED-1500 was used.

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