• Journal of Periodontal and Implant Science
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• v.43 no.2
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• pp.101-105
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• 2013

Purpose: The present study aimed to measure root surface roughness in teeth with periodontitis by a profilometer following root planning with ultrasonic and hand instruments with and without erbium-doped yttrium aluminium garnet (Er:YAG) laser irradiation. Methods: Sixty single-rooted maxillary and mandibular teeth, extracted because of periodontal disease, were collected. The crowns and apices of the roots were cut off using a diamond bur and water coolant. The specimens were mounted in an acrylic resin block such that a plain root surface was accessible. After primary evaluation and setting a baseline, the samples were divided into 4 groups. In group 1, the samples were root planned using a manual curette. The group 2 samples were prepared with an ultrasonic scaler. In group 3, after scaling with hand instrumentation, the roots were treated with a Smart 1240D plus Er:YAG laser and in group 4, the roots were prepared with ultrasonic scaler and subsequently treated with an Er:YAG laser. Root surface roughness was then measured by a profilometer (MahrSurf M300+RD18C system) under controlled laboratory conditions at a temperature of $25^{\circ}C$ and 41% humidity. The data were analyzed statistically using analysis of variance and a t-test (P<0.05). Results: Significant differences were detected in terms of surface roughness and surface distortion before and after treatment. The average reduction of the surface roughness after treatment in groups 1, 2, 3, and 4 was 1.89, 1.88, 1.40, and 1.52, respectively. These findings revealed no significant differences among the four groups. Conclusions: An Er:YAG laser as an adjunct to traditional scaling and root planning reduces root surface roughness. However, the surface ultrastructure is more irregular than when using conventional methods.

• Korean Journal of Bronchoesophagology
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• v.16 no.1
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• pp.20-26
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• 2010

Transoral $CO_2$ Laser Microsurgery of glottic Carcinoma is replacing external approaches. The qualify of life after surgery for laryngeal cancer may be as important as complete resection of the tumor for patient. Transoral $CO_2$ laser cordectomy for the management of early laryngeal cancer has advantages with regard to oncological results, preservation of laryngeal functions, morbidity and cost in comparison to those of open surgery or radiation therapy. Moreover, transoral laser surgery can be a useful choice as a salvage surgery in radiation therapy failed early glottic cancer. A classification of laryngeal endoscopic cordectomies which included eight different types was described by the European laryngological Society in 2000. We will also introduce type VI which was newly proposed recently.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.496-496
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• 2007

Low level laser therapy has various therapy effects. This paper performed the basic study for fabricating the low level laser therapy apparatus, and one of the goals of this paper was to make this apparatus used handily. The apparatus has been fabricated using the laser diode and microprocessor unit. The apparatus used a 7850m Laser diode for blood stream improvement and was designed for a pulse width modulation type to increase stimulation effects. In result, we could get the light power of 785nm wavelength.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.40.3-40
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• 2001

The pulsed Nd:YAG laser is the most commonly used type of solid-state laser in many fields. In material processing and medical treatment, the power density control of a laser beam Considered to be significant, which depends on the flashlamp current pulse width and pulse repetition rate. For general laser power supply to control the laser power density, the secondary of the power transformer is connected to the rectifier and filter capacitor. The output of a rectifier is applied to a switching element in the secondary of the transformer. So power supply is complicated and the loss of switching is considerably. In addition, according to increasing pulse repetition rate, charged energy of energy-storage capacitor bank is not transferred sufficiently to flashlamp, and laser output efficiency decreases. In this study, we have ...

• Archives of Plastic Surgery
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• v.42 no.1
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• pp.52-58
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• 2015

Background The erbium:yttrium scandium gallium garnet (Er:YSGG) laser differs from other laser techniques by having a faster and higher cure rate. Since the Er:YSGG laser causes an appropriate proportion of ablation and coagulation, it has advantages over the conventional carbon dioxide ($CO_2$) laser and the erbium-doped yttrium aluminum garnet (Er:YAG) laser, including heating tendencies and explosive vaporization. This research was conducted to explore the effects and safety of the Er:YSGG laser. Methods Twenty patients participated in the pilot study of a resurfacing system using a 2,790-nm Er:YSGG laser. All patients received facial treatment by the 2,790-nm Er:YSGG laser system (Cutera) twice with a 4-week interval. Wrinkle reduction, reduction in pigment inhomogeneity, and improvement in tone and texture were measured. Results Study subjects included 15 women and five men. Re-epithelization occurred in all subjects 3 to 4 days after treatment, and wrinkle reduction, reduction in pigment inhomogeneity, and improvement in tone and texture within 6 months of treatment. Conclusions The 2,790-nm YSGG laser technique had fewer complications and was effective in the improvement of scars, pores, wrinkles, and skin tone and color with one or two treatments. We expect this method to be effective for people with acne scars, pore scars, deep wrinkles, and uneven skin texture and color.

• Tuberculosis and Respiratory Diseases
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• v.43 no.6
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• pp.1028-1034
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• 1996

The leiomyoma of the bronchus is a very rare benign tumor in the lower respiratory tract. Though classical treatment of the bronchial leiomyoma is surgical resection, bronchoscopic tumor resection has been recently applied to selected cases. We experienced two cases of bronchial leiomyomas which were successfully resected under flexible bronchoscopy using Nd-YAG laser and bronchial snare. We speculated that bronchoscopic resection of the bronchial leiomyoma would be an effective and safe way of treatment, and more technical developments should follow.

• Restorative Dentistry and Endodontics
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• v.39 no.4
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• pp.296-302
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• 2014

Objectives: It is difficult to achieve adhesion between resin cement and zirconia ceramics using routine surface preparation methods. The aim of this study was to evaluate the effects of $CO_2$ and Er:YAG laser treatment on the bond strength of resin cement to zirconia ceramics. Materials and Methods: In this in-vitro study 45 zirconia disks (6 mm in diameter and 2 mm in thickness) were assigned to 3 groups (n = 15). In control group (CNT) no laser treatment was used. In groups COL and EYL, $CO_2$ and Er:YAG lasers were used for pretreatment of zirconia surface, respectively. Composite resin disks were cemented on zirconia disk using dual-curing resin cement. Shear bond strength tests were performed at a crosshead speed of 0.5 mm/min after 24 hr distilled water storage. Data were analyzed by one-way ANOVA and post hoc Tukey's HSD tests. Results: The means and standard deviations of shear bond strength values in the EYL, COL and CNT groups were $8.65{\pm}1.75$, $12.12{\pm}3.02$, and $5.97{\pm}1.14MPa$, respectively. Data showed that application of $CO_2$ and Er:YAG lasers resulted in a significant higher shear bond strength of resin cement to zirconia ceramics (p < 0.0001). The highest bond strength was recorded in the COL group (p < 0.0001). In the CNT group all the failures were adhesive. However, in the laser groups, 80% of the failures were of the adhesive type. Conclusions: Pretreatment of zirconia ceramic via $CO_2$ and Er:YAG laser improves the bond strength of resin cement to zirconia ceramic, with higher bond strength values in the $CO_2$ laser treated samples.

• Korean Journal of Optics and Photonics
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• v.18 no.3
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• pp.208-215
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• 2007

A fiber-coupled laser-diode pumped ceramic Nd:YAG laser for compensating the thermal tensing effect was developed. The thermal tensing effect was compensated using a convex lens, which was 25 mm away from the laser rod, with a focal length of 30 mm and an effective clear aperture of 22 mm. Without a compensator, the laser output power decreased suddenly above a pump power of 6 W. Using a compensator, the laser output power increased linearly according to the pump power. The beam propagation factor $M^{2}$ was 2.4 under a pump power of 12 W.

• Journal of Acupuncture Research
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• v.26 no.6
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• pp.21-30
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• 2009

Objectives : Being introduced in the 1980s, laser acupuncture studies have been steadily carried on such as its thermal effects on human body. However, the mechanisms of effect are not yet clearly explained. Generally, laser acupuncture could be favorable for pediatric patients or people under special conditions (hemophilia, needle-phobia, pathogen-carriers, etc.) because of lower risk of infection, bleeding, pain or fainting. But there are still problems for using laser acupuncture equivalently as the traditional metal needle. The goal of this study is to review the fundamentals, history and present trend of laser acupuncture study, and to suggest how to develop laser acupuncture as an oriental medical device. Method : We performed literature search using PubMed(http://www.ncbi.nlm.nih.gov/pubmed) and Scopus(http://www.scopus.com). Search conditions are laser acupuncture, laser needle, LLLT(as title or abstract) or Litscher G(as author). Main target studies are physical fundamentals, clinical trials, physiological results and device proposals. Results : Many research have shown the similarities of laser acupuncture and traditional metal acupuncture and have reported clinical and physiological effects of laser acupuncture. But, still laser acupuncture is not widely used in Korea due to high-cost of equipments and the lack of clear understanding of laser devices. Additionally, there are still challenges in standardization and device development. Conclusions : Frequencies, laser modes, waveguides, adaptor types, polarization and signal modulations are suggested as future study subjects on laser acupuncture. More various studies and efforts for device development have to be performed to provide oriental medical doctors with evidence based confidence about usage of laser acupuncture.

• Journal of Biomedical Engineering Research
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• v.31 no.6
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• pp.472-480
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• 2010

Mechanically deformed cartilage undergoes a temperature dependent phase transformation resulting in reshaping of cartilage. Laser-assisted cartilage reshaping (LCR) is recently introduced to recreate the underlying cartilage framework in structures such as ear, larynx, trachea, and nose. However, this procedure has not been fully supported by confirmed efficacy because of the lack of scientific research and its safety issues. The purpose of this study is to evaluate current laser sources to determine optimal laser wavelength for LCR using mathematical simulations and investigate optical, thermo-mechanical, and backscattering properties of cartilage after laser irradiation. The results showed that 1444 nm wavelength was effective for reshaping of cartilage with minimal thermal damage in the surrounded tissues by monte carlo simulations. Analysis of bend angle changes, thermo-mechanical characteristics, and backscattered properties may be useful to better identify the biophysical transformation responsible for stress relaxation in cartilage and develop an optical feedback control methodologies.