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Source publication
Choosing the right light-curing unit can be a very difficult task for some orthodontists. Currently, there are various types of light curing units available in the market with various trade names and specifications. Most of the time information regarding light curing units is obtained from advertisements, websites or manufacturers' catalogues. Some...
Contexts in source publication
Context 1
... specifications of light-curing units which are available in the market are summarized in Table 1. ...
Citations
... Usually, the light output required for polymerization varies between 360 to 500 nm and more specifically for camphorquinone, which is the most often used photo-initiator in resin composites, the optimum absorption occurs near the wavelength of 470 nm. 19 Therefore, in the present study we preferred three different light units having wavelength range covering the absorbance wavelength of camphorquinone. ...
Objective
To evaluate the effects of three different curing units on the physical and mechanical features of three different orthodontic adhesive resin materials.
Material and Methods
45 specimens (5 mm in diameter, and 2 mm in thickness) of each of the three different adhesive composite resin materials (Transbond XT, Grēngloo™ Adhesive and Light Bond Paste) were cured with three different light units (a polywave third generation (Valo), a monowave (DemiUltra), and a second-generation LED (Optima 10)). To quantify degree of conversion (DC), the Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy was used in transmission mode (ALPHA FT-IR Spectrometer, Bruker Optics, Germany). Vickers hardness value was recorded under constant load 100 g for 10 s with a microhardness tester (HMV M-1, Shimadzu Corp., Kyoto, Japan). The data were statistically analyzed using Kruskal-Wallis and chi-square tests. The level of significance was considered p < 0.05.
Results
The highest DC values were obtained as a result of curing with Optima 10. This rate was followed by Demi Ultra and Valo, respectively. Transbond XT samples showed a lower level of conversion than the samples of Light Bond Paste and Grēngloo™ Adhesive. The top surfaces of each material showed higher hardness values than the bottom surfaces ( p < 0.05). The Light Bond Paste showed the highest hardness values both on the top and bottom surfaces among the three materials, followed by Grēngloo™ Adhesive. While the hardness values of the top surfaces of the samples cured with Demi Ultra and Valo light units were similar, higher hardness values are recorded with Valo on the bottom surfaces (Valo; 85.200/75.200 (top/bottom) versus Demi Ultra; 86.100/66.000 (top/bottom)).
Conclusions
The different DC and the surface hardness properties were recorded for the resin as orthodontic adhesives depending on different light units. Shorter radiation time caused lower DC and surface hardness values.
... The basic components of light-curing units are as follows [ Figure 2]: handpiece, handpiece push button, nose cone, light guide, eye shield, power module, power cord, main switch, indicator light, fuse, plug, bulb, filter, and fan. [5][6][7] Some of the light-curing units have integrated curing meter, microprocessor, and battery charger. [5,8] To lowest to highest intensity • LED lamps • Quartz-tungsten halogen lamps • PAC lamps • Argon laser lamps. ...
... [5][6][7] Some of the light-curing units have integrated curing meter, microprocessor, and battery charger. [5,8] To lowest to highest intensity • LED lamps • Quartz-tungsten halogen lamps • PAC lamps • Argon laser lamps. ...
... The technology came from other industry such as ink, paint, and coating materials that used the UV in photopolymerization process. [5,9,10] This unit utilized the polymerization process of a composite that can be accomplished by the energy derived from ultraviolet light. The wavelength is in the range of 364-367 nm. ...
Introduction
The final physical and mechanical properties of composites are determined by the degree of conversion (DC%) of monomer in the composite, which in turn determines the quality of bonding. Incomplete conversion of monomer might lead to the leach of various chemical compounds from the uncured resin.
Aims and Objectives
This study assessed the DC% of Transbond XT composite resin when cured with three different light-curing units using Fourier transform infrared (FTIR) spectroscopy.
Materials and Methods
A total of 60 metallic brackets were used. The bonding system was Transbond XT Primer, followed by Transbond XT composite resin that cured for 10 s, 3 s with Elipar DeepCure-L 3M and Woodpecker iLED, respectively, as recommended by the manufacturers and 20 s by BeeCool light-emitting diode-corded (taken as control) on extracted natural teeth which were mounted on the plaster of Paris base. One millimetre was used to standardise the distance between the light source and each specimen. Immediately after polymerisation, the debonded cured composites were tested using FTIR spectroscopy to assess DC%. Non-cured resin specimens were also subjected to FTIR spectroscopy, to serve as non-cured references.
Results
With 3M, Woodpecker and BeeCool, the DC% of monomer was 58.83%, 58.53% and 21.55%, respectively. No statistically significant difference was found between 3M and Woodpecker lights. BeeCool showed significantly lower DC%.
Conclusion
It is essential for clinicians to have prior knowledge of light-curing units before committing to purchase one as the reduction in exposure time is beneficial for both the patient and the orthodontist.
The purpose of this study was to investigate the effect of light curing tip angulations on the shear bond strength of an orthodontic adhesive. Three groups of thirty premolar teeth had brackets attached in a standardized man-ner using Transbond XT. The orthodontic adhesive were cured with a Blue LED light curing unit for 40 seconds using three different angulations 0 o , 45 o and 90 o at a standardized 3 mm distance. The debonding force was measured using an Instron Universal Testing Machine. Data were computed and analysed using SPSS version 12.0. Kruskal-Wallis test was employed to compare the shear bond strength of all groups. The study found that there was no significant difference on the shear bond strengths of orthodontic adhesive when cured at the angulations of light curing tip of 0 o , 45 o and 90 o .
The purpose of this study was to investigate the light intensity of selected light curing unit with varying distance and angulation of the light curing tip and lightmeter.
Four types of light units; Spectrum 800 (Dentsply), Coltulux 3 (Coltene), Elipar FreeLight 2 (3M Espe) and Starlight Pro (Mectron) were evaluated for light intensity at various distance between the light curing tip and the lightometer Cure Rite Denstply (0, 1, 3, 5, 10 and 15 mm). The light curing units were angulated at 45°, 60° and 90° at a standardized 5 mm distance.
The intensity of light curing is affected by the distance between the light curing tip and the lightmeter. However, the decrease in light intensity of the light curing unit was found not to obey the inverse square law for the distances 0 to 15 mm.
The study found that there was no significant difference between 45° and 60° angulation between the light curing tip and the lightmeter. However, the decrease in light intensity is significant when compared to the light tip is placed perpendicular (90°) to the aperture of the light meter.
