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PDF Cavity Disinfection Using Er,Cr:YSGG Laser Induced Photoacoustic Streaming Technique: Rand kareem Jassim Hussein Ali Jawad*
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Abstract:

Aim: The goal of this research was to study the influence of Er,Cr:YSGG laser at short pulse duration (60 µsec) on the number of streptococcus mutans bacteria in vitro.

Material and Methods:  twenty-eight extracted third molars free of caries, cracks, and other irregularities were used. For the testing of the materials, both the agar well technique and a tooth cavity model were employed. The agar wells of plates that had been inoculated with Streptococcus mutans previously were stuffed with the test materials, in order to conduct the tests. The zones of inhibition were assessed using millimeter measurements, after an incubation period of 48 hours .In order to accomplish the tooth cavity model test, cylindrical cavities were invented in the occlusal surface of the teeth, which was kept even. The teeth were stored for 72 hours at 37°C in a broth culture of Streptococcus mutans. Following this, the teeth were divided arbitrarily into four groups of seven teeth (each including 14 cavity preparations). The experimental cavities in the first group (A) were not treated and considered as a control. In group B, a cavity disinfectant based on chlorhexidine was applied to the experimental cavities for 60 seconds. In group C, an erbium, chromium doped yttrium scandium gallium garnet laser was used at a short pulse duration (60 µsec) (0.25 watts, 15 Hz, 1% air, 1% water). In the last group, a chlorhexidine cavity disinfectant was applied for 60 seconds, followed by a laser treatment for 30 seconds with the same parameters as those described previously. The teeth were stored in saline for a period of three days. Standard amounts of dentin chips were retrieved from the cavity walls. ANOVA test was used to analyze repeated measure mean between tested concentration and control. Data expressed as mean ±SE.  LSD tests was used to calculate the significant differences between tested mean.

Result: After the statistical test, the highly significant difference in the diameter of inhibition zone was observed in group D (26 mm) where both chlorhexidine and laser were used followed by group B (18.71 mm) where the chlorhexidine gluconate based cavity disinfectant used alone, the least significant difference observed in group C (10.26mm) where the laser used alone.

Conclusion: According to this in vitro study, a photon-induced photoacoustic streaming technique using an Er,Cr:YSGG pulse laser at short pulse duration effectively agitates a chlorhexidine-based cavity disinfectant, which leads to the inhibition of Sterptococcus Mutans.

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Publication Date
Sat Oct 01 2011
Journal Name
Iraqi Journal Of Physics
Nanocrystalline -Silicon Carbide Films Prepared by TEACO2 Laser
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Thin films of microcrystalline and nanocrystalline -silicon carbide and silicon, where deposited on glass substrate with substrate temperature ranging from 350-400C, with deposition rate 0.5nm per pulse, by laser induced chemical vapor deposition. The deposition induced by TEACO2 laser. The reactant gases (SiH4 and C2H4) photo decompose throughout collision associated multiple photon dissociate. Such inhomogeneous film structure containing crystalline silicon, silicon carbide and amorphous silicon carbide matrix, give rise to a new type of material nanocrystalline silicon carbide in which the optical transmittance is governed by amorphous SiC phase while nanocrystalline grain are responsible for the conduction processes. This new m

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Publication Date
Thu Dec 23 2021
Journal Name
Iraqi Journal Of Science
Effect Of Nd:YAG Laser On Ants (Camponotus consobrinus)
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     The subject of biophysics is interdisciplinary and covers various fields of biology and physics. In this research the effect of some parameters of Nd:YAG laser on ants (Camponotus consobrinus) has been studied    . This includes the effect on its external shape, as well as the percentage of the killing rate obtained. A laser radiation  of  a wavelength (1.064 µm) with different  energies: (300, 320, 340, 360, 380 and 480 mJ) was used to irradiate ants  placed at a distance  of (10 cm) distance  from the laser source . The irradiation times were (15 and 20 sec) for each energy. The obtained results showed an increase in the rate of ant  mortality, as well

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Publication Date
Mon Oct 01 2018
Journal Name
Iraqi Journal Of Physics
Nanosecond laser pulses for aluminum and copper drilling
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Nd:YAG laser pulses of 9 nanosecond pulse duration and operating wavelength at 1.06 μm, were utilized to drill high thermal conductivity and high reflectivity aluminum and copper foils. The results showed a dependence of drilled holes characteristics on laser power density and the number of laser pulses used. Drilled depth of 74 ϻm was obtained in aluminum at 11.036×108 W/cm2 of laser power density. Due to its higher melting point, copper required higher laser power density and/or larger number of laser pulses to melt, and a maximum depth of 25 μm was reached at 13.46×108 W/cm2 using single laser pulse.

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Publication Date
Sun Aug 01 2021
Journal Name
Laser Micro- And Nano-scale Processing
Effective working parameters of laser micro-/nano-machining
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Modern emerged technologies impose development and fabrication of miniatur-ized parts and devices in the micro- and nano-scale. Producing micro- and nano-featured structures requires nonconventional machining processes where con-ventional machining processes such as grinding, milling and eroding have failed. New emerging processes, such laser machining processes, are still fraught with almost invincible processes. Micro-/nano-machining are the pro-cesses of producing parts, microsystems or features at a scale of a few microm-eters and less than one hundred nanometers, respectively. Precise cutting and clean material removal accompanied with a negligible heat affected zone (HAZ), which are usually the characteristics of laser ablation, have

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Publication Date
Wed Dec 01 2021
Journal Name
Baghdad Science Journal
New Spectral Range Generations from Laser-plasma Interaction
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            High-intensity laser-produced plasma has been extensively investigated in many studies. In this demonstration, a new spectral range was observed in the resulted spectra from the laser-plasma interaction, which opens up new discussions for new light source generation. Moreover, the characterizations of plasma have been improved through the interaction process of laser-plasma. Three types of laser were incorporated in the measurements, continuous-wave CW He-Ne laser, CW diode green laser, pulse Nd: YAG laser. As the plasma system, DC glow discharge plasma under the vacuum chamber was considered in this research. The plasma spectral peaks were evaluated, where they refer to Nitrogen gas. The results indicated that the

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Publication Date
Tue Mar 30 2021
Journal Name
Baghdad Science Journal
Experimental Evidence of Chaotic Resonance in Semiconductor Laser
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In this paper, an experimental study has been conducted regarding the indication of resonance in chaotic semiconductor laser.  Resonant perturbations are effective for harnessing nonlinear oscillators for various applications such as inducing chaos and controlling chaos. Interesting results have been obtained regarding to the effect of the   chaotic resonance by adding the frequency on the systems. The frequency changes nonlinear dynamical system through a critical value, there is a transition from a periodic attractor to a strange attractor. The amplitude has a very relevant impact on the system, resulting in an optimal resonance response for appropriate values related to correlation time. The chaotic system becomes regular under

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Publication Date
Sun Mar 06 2011
Journal Name
Baghdad Science Journal
Laser Effect on Fatique Resistance of Carbon Steel
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Laser beam has been widely used to improve the mechanical properties of the metals. It used for cutting, drilling, hardening, welding……etc. The use of Laser beam has many features in accuracy and speeding in work, also in the treatment of metals locally, and in the places that is hard to reach by traditional ways. In this research a surface treatment was done to medium carbon steel (0.4%C) which is common kind of steel that is used in industry. Pulsing Neodymium -YAG Laser has been used and 1.06 micrometer wave length and 5 msec and the distance is about 30 centimeter between the exit area of the Laser beam from the system and the piece that treated . We are going to check the fatigue resistance for samples that is

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Publication Date
Fri Jan 01 2016
Journal Name
Modern Applied Science
New Combined Technique for Fingerprint Image Enhancement
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This paper presents a combination of enhancement techniques for fingerprint images affected by different type of noise. These techniques were applied to improve image quality and come up with an acceptable image contrast. The proposed method included five different enhancement techniques: Normalization, Histogram Equalization, Binarization, Skeletonization and Fusion. The Normalization process standardized the pixel intensity which facilitated the processing of subsequent image enhancement stages. Subsequently, the Histogram Equalization technique increased the contrast of the images. Furthermore, the Binarization and Skeletonization techniques were implemented to differentiate between the ridge and valley structures and to obtain one

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Publication Date
Sat Jan 01 2011
Journal Name
Iraqi Journal Of Science
A CRYPTOGRAPHIC TECHNIQUE BASED ON AVL TREE
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Publication Date
Wed Jun 12 2019
Journal Name
Dirasat: Human And Social Sciences
Teaching by pause technique in the classroom
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Communication represents the essence of language learning. Since the unspecified evolution of conveying information, human beings have been employing the main constituents of language with short pauses. Although the punctuation marks necessitate short expressions among thought group of words in writing, human language demand for understanding how and when to pause orally. This paper presents the pause technique in the classroom. It signifies the relation between pausing and lecturing in the class and determines its sufficient time-management to interact with college learners of different specializations. The conduct study reviewed teaching pause technique in the empirical studies at Special Education and Communication Disorders of Pennsylva

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