Nd: YAG 레이저 조사가 Clacium Fluoride 형성 및 치아 내산성에 미치는 영향

최병재,김성오,손흥규,이제호,박광균 大韓小兒齒科學會 1999 大韓小兒齒科學會誌 Vol.26 No.2

불소도포시 주로 형성되는 calcium fluoride는 구강내 환경에서 pH에 의해 조절되는 불소의 저장고 역할을 하여 치아우식 예방에 있어서 중요한 역할을 하는 것으로 알려져 있다. 따라서 불소도포의 우식예방 효과는 calcium fluoride를 얼마나 많이 형성시켜 오래 지속시키는 가에 달려있다. 이에 치아 내산성 증가에 효과 있다고 알려진 Nd:YAG 레이저 조사가 calcium fluoride형성 및 치아 내산성에 미치는 영향에 대해 알아보기 위해서 실험을 시행하였다. 소의 영구전치에서 276개의 시편을 제작하여 아무런 처치를 하지 않은 군을 대조군으로 하고 1.23% acidulated phosphate fluoride (APF) 5분, 30분 도포 및 Nd:YAG 레이저 조사에너지 밀도 20J/㎠,40J/㎠의 조건에 따라 불소 도포군, 레이저 조사군, 불소 도포후 레이저 조사군, 레이저 조사후 불소 도포군으로 분류하였다. 불소도포를 시행한 경우 이를 다시 KOH 처리 여부에 따라 나누어 23개의 실험조건을 만들었다. 각 실험조건에 12개의 시편을 배정하고 이중 10개의 시편은 불소 및 무기인 측정에, 나머지 2개의 시편은 표면 관찰에 사용하였다. KOH 비처지군에서 0.1N HCIO4로 enamel biopsy를 시행하여 탈회 법랑질의 불소농도 및 탈회깊이를 측정하였으며, KOH 처치군에서는 1 M KOH로 24시간 처리하여 calcium fluoride를 정량 후 enamel biopsy를 시행하였다. 실험결과 얻어진 자료 및 주사 전자현미경 관찰 소견을 비교하여 다음의 결과를 얻었다. 1. KOH 비처치군에서 탈회된 법랑질의 불소농도는 레이저조사 후 불소도포시 레이저 에너지 밀도 증가에 따라 증가되는 경향을 보였다. 2. KOH 비처치군에서 법랑질 탈회깊이는 불소를 5분 도포후 레이저 20J/㎠를 조사한 경우를 제외하고는 레이저와 불소를 병행하여 처치시 각각을 단독으로 치치시보다 탈회깊이가 작았다 (p<0.05). 3. Calcium fluoride의 양은 레이저의 조사에 의해 유의 있게 증가하지 않았다 (p>0.05). 4. Calcium fluoride 입자는 불소만 도포한 경우에 비해 레이저 조사후 불소도포시 입자크기가 증가되었으며, 불소도포후 레이저 조사시 입자크기의 증가와 함께 일부 융합된 양상을 보였다. 5. KOH 처치군에서 법랑질의 불소농도는 불소를 30분 도포후 레이저를 조사한 경우를 제외하고는 대조군의 불소농도와 유의한 차이가 없었다(p>0.05). 6.KOH 처치군에서 불소와 레이저를 병행한 경우, 불소만 도포한 경우보다 탈횐된 법랑질의 깊이가 작았다 (p<0.05). 7. KOH 비처치군에서 탈회된 법랑질의 불소농도와 탈회깊이의 상관관계 (Spearman correlation coefficient: -0.6281)는 KOH 처치군 (Spearman correlation coefficient: -0.3792)에 비해 높은 음의 상관 관계를 보였고, 동일한 조건으로 불소도포 및 레이저 조사를 시행한 경우에 있어서 KOH 처리 여부에 따른 탈회법랑질 깊이의 유의차가 있는 경우 calcium fluoride의 형성량이 많았다. 이상의 실험결과로 미루어 보아 레이저 조사가 calcium fluoride의 형성량에 영향을 미치지 않았으나 레이저 조사의 영향으로 calcium fluoride의 용해가 감소하는 것으로 판단된다. 또한 불소도포 및 레이저 조사의 병행은 각각을 단독으로 처치한 경우에 비하여 치아 내산성 증가면에서 유리하므로 임상에서 불소도포주기 연장과 같은 유용한 결과를 얻을 수 있을 것으로 생각된다. Calcium fluoride. created by topical fluoride application, is the reservoir for fluoride ion regulated by pH in the oral environment. Therefore, the amount and the maintenance of calcium fluoride have an important role in preventing dental caries. The aim of this study is to evaluate the effect of Nd:YAG laser irradiaiton on the generation of calcium fluoride and the acid resistance of tooth enamel. The bovine anterior permanent teeth were prepared (n=276), and divided into following groups: no treatment(control), fluoride application alone, laser irradiation alone, laser irradiation after fluoride application, and fluoride application after laser irradiation. And each group was subdivided based on the application time of 1.23% acidulated phosphate fluoride (APF) (5 min and 30 min) and the irradiation energy of Nd:YAG laser (20J/㎠ and 40J/㎠). In case of fluoride application, each group was divided according to KOH treatment. Twenty three treatment conditions were made for this experiment and twelve specimens were assigned to each treatment condition. In each treatment condidtion, ten specimens were used for chemical analysis and two specimens were observed under SEM. In groups without treating KOH, fluoride content and the depth of enamel dissolved were measured using enamel biopsy technique. In groups with treating KOH, the amount of calcium fluoride was measured by the treatment with 1 M KOH for 24 hours and enamel biopsy was performed after KOH treatment. The results were analyzed by the fluoride content and the depth of enamel dissolved by enamel biopsy, amount and thickness of calcium fluoride, and the surface structures of enamel. The results are as follows: 1. In groups without treating KOH, the fluoride content of removed enamel showed a positive relationship with the energy density of laser when the laser irradiated before fluoride application. 2. In groups without treating KOH, the depth of enamel dissolved decreased more with the combined laser and fluoride treatment than with laser or fluoride treatment, except for the case of 20J/㎠ laser irradiation after 5 minute fluoride application (p<0.05). 3. The amount of calcium fluoride did not increased by laser treatment with no statistical significance(p>0.05). 4. The particle size of calcium fluoride increased in case of fluoride treatment after laser irradiation, compared with fluoride application alone. In case of laser treatment after fluoride application, the particle size of calcium fluoride increased and some of the particles fused as well. 5. There were no significant differences in the fluoride content of dissolved enamel between groups without treating KOH and control group, except for the case of laser irradiation after treatment of APF for 30 minutes (p>0.05). 6. In groups with treating KOH, depth of removed enamel in the groups of combined treatment with laser and fluoride was shallower than that in fluoride application groups (p<0.05). 7. In groups without treating KOH, the relationship between fluoride content and the depth of enamel dissolved showed more negative (Spearman correlation coefficient: -0.6281)than in groups with treating KOH (Spearman correlation coefficient: -0.3792). The greater amount of calcium fluoride could be found in case where there was a significant differences of the depth of enamel dissolved between groups with and without treating KOH. From these results, it can be concluded that laser seems to be a little effects on the amount of calcium fluoride formation, but has some effect on the lowering the solubility of calicium fluoride. As the combined treatment of laser and fluoride application showed more effective acid-resistant property, more extended recall period for fluoride application can be achieved with this combined treatment in the clinic.

레이저침 시술에 사용되는 레이저 기기의 적용 범위에 대한 고찰

황의형,양창섭,장인수 대한침구의학회 2009 대한침구의학회지 Vol.26 No.1

Objectives : During the past three decades there has been a significant evolution of laser acupuncture application in the nature of the clinical approach and the research of traditional medicine and laser therapy field. However, there have been no standard and guideline of laser equipment can be applied as laser acupuncture. This study aims to investigate the condition of laser equipment required as a laser acupuncture method. Methods : First, we performed literature search using the Medline (from 1999 to Oct 2008) to confirm types and ranges of laser equipments that can be applied as laser acupuncture. In addition, we investigated the characters of acupoints such as sites and depths, and compared with penetrating depths of each laser. Results : A total of 37 articles for clinical studies using laser acupuncture were selected, and 41 lasers were used. GaAs laser was used three times, GaAlAs laser 14, InGaAlP 18, HeNe laser 4, and Argon laser and CO2 laser were used one time, respectively. From all 361 points of fourteen meridians, depths of 341 points(94.5%) were 1 cun (2.3-3.2cm) or less. The mean depth of all points was 0.48 cun(1.1-1.5cm). Hence, it appeared that the majority of therapeutic lasers satisfied with the condition. HeNe, InGaAlP, GaAlAs, GaAs lasers are recommended for laser acupuncture, however, it may plausible that other surgical lasers could be used as the laser acupuncture, because it have the biostimulation effect to some extent, too. Conclusions : It is suggested that to select appropriate laser type and give the adequate output power to reach the acupoints under the skin using laser acupuncture. Further evaluation and research for the condition of laser acupuncture are warranted.

External application of 1444-nm Nd:YAG laser for extensive xanthelasma

( Sang Hyeon Won ),( Woo Il Kim ),( Min Young Yang ),( Won Ku Lee ),( Gun Wook Kim ),( Hyun Chang Ko ),( Byung Soo Kim ),( Moon Bum Kim ),( Hoon Soo Kim ) 대한피부과학회 2019 대한피부과학회 학술발표대회집 Vol.71 No.1

Xanthelasma is a subtype of plane xanthoma occurs on periorbital regions and causes substantial cosmetic and psychosocial burden for patients. Various methods including surgical excision, topical therapy and laser therapy have been used for the treatment of xanthelasma depending on the location and size of the lesion. All these methods have some advantages and disadvantages, gold-standard treatment has not been established. We present the case of a 46-year-old woman with a 1-year history of yellowish large plaques on both lower eyelids, clinically consistent with xanthelasma. Laser therapy was selected in order to prevent possible functional impairment such as ectropion or scar after surgical excision. Split-face trial was performed to allow comparison of therapeutic effect between 1444nm Nd:YAG laser for the right and fractional CO2 laser for the left lesion. 1444nm Nd:YAG laser treatment showed excellent lesion clearance and high patient’s satisfaction, although there was longer down-time and post-laser erythema as compared with fractional CO2 laser. After 6 months of 1444nm Nd:YAG laser therapy, more significant cosmetic improvement was achieved than fractional CO2 laser. To our knowledge, external application of 1444nm Nd:YAG laser for extensive xanthelasma has not been reported in Korean dermatologic literature, and it can be considered as one of effective therapeutic options for xanthelasma based on our experience.

The Effect of Combined Application of Argon and Nd-YAG Laser on Iridectomy in Rabbits

Park, Chan,Rhee, Sang Wook CATHOLIC MEDICAL CENTER 1987 Bulletin of the Clinical Research Institute Vol.15 No.1

Recently iridectomy using argon or Nd-YAG laser to treat narrow angle glaucoma has become popular, and is now a procedure of choice over the standard surgical technique. However, shock wave of Nd-YAG laser causes hemorrhage in almost all cases and high energy level of Nd-YAG laser, which is required for iridectomy, causes injuries to the lens and cornea. Furthermore, there is a tendency toward closure of the iridectomy site after argon laser application. We performed iridectomies by combined application of argon and Nd-YAG laser in pigmented rabbits to improve iris bleeding, iridectomy patency, and lens and corneal damage. The iridectomy patency and the lens and corneal damage were examined with scanning electron microscope. The rabbits that underwent laser iridectomies with only Nd-YAG laser were used as a control group. The following results were obtained: 1. The bleeding rate of the iridectomy in the combined application group was 2.4% and in the control group 98.8% proving the combined application of both laser to be highly effective. 2. In the experimental group, the patency rate of iridectomy was 33.3% at the energy level of 1 mJ, 66.6% at 2 mJ, 83.3% at 4 mJ, and 6 mJ, respectively. In the control group, the patency rate of iridectomy was 33.3% at the energy level of 4 mJ, 63.6% at 6 mJ, 83.3% at 8 mJ, respecively. At the same energy level, the experimental group showed a higher rate of patency than the control group. 3. In both the experimental and control groups, the lens damge was noted at the energy level of 6 mJ or higher. The lens was not affected by lower energy Nd-YAG laser. 4. In the experimental and control groups, the corneal damage was observed at the energy level of 8 mJ or higher. The cornea was not affected by low energy Nd-YAG laser. Based on the above results, it can be concluded that laser iridectomy by combined application of argon and Nd-YAG lasers results in a lower rate of bleeding, a higher rate of patency, and less damage to the lens and cornea as compared with iridectomy performed by Nd-YAG laser only.

지상-우주 레이저 연구를 위한 큐브위성 CLUB(CNU Laser Unity Bus)의 임무 중심 개념설계

Seok-Min Song,Ho Sub Song,Chae-Ryeong Kim 한국우주과학회 2024 우주기술과 응용 Vol.4 No.1

본 논문에서 우리는 여러 지상-우주 레이저 어플리케이션의 통합 인프라를 제공하는 ‘충남대학교 레이저통합 버스’(Chungnam National University Laser Unity Bus, CLUB) 큐브위성의 컨셉을 소개한다. 오늘날뉴스페이스 시대에 들어 우주공간의 활용이 급속도로 확대되면서 전파의 한계가 드러나기 시작했고, 수행하는 임무들이 다양해짐에 따라 대체 가능한 수단인 레이저가 주목 받고 있다. 레이저는 지상과 우주공간사이에서 인공위성 레이저 거리측정(satellite laser ranging, SLR), 레이저 무기, 레이저 통신 등 다양한 응용분야에 이용할 수 있다. 하지만 지상과 우주공간 사이에서 사용되는 레이저는 지구 대기의 상당한 영향을 받게 된다. 이에 레이저 전파에 영향을 미치는 대기효과에 대한 이해가 필수적으로 요구된다. 특히 레이저의 전파 방향을 굴절시키고 파면을 왜곡시키는 대기 난류는 지상과 가까워질수록 강해지기 때문에 하향링크에 비해 상향링크에 더 큰 영향을 미친다. 하향링크의 경우 지상에서 검출할 수 있기 때문에 검증이용이한 반면, 상향링크의 경우 우주공간에서 검출해야 하는 어려움 때문에 검증에 어려움이 있다. 이에 우리는 상향링크의 레이저 전파에 대한 이해를 돕고 검증하기 위한 큐브위성의 아이디어를 제안한다. 또한체계적인 큐브위성 개발을 위해 시스템공학의 진행단계에 따라 CLUB 큐브위성의 임무설계를 중심으로요구사항을 분석하여 개념설계를 진행한 결과를 제시한다. In this paper, we introduce the concept of the cube satellite Chungnam National University Laser Unity Bus (CLUB), which can provide an integrated infrastructure for various ground-space laser applications. With the advent of the new space era, the rapid expansion of space utilization has begun to reveal the limitations of conventional radio frequencies. As space missions diversify, lasers are garnering attention as a viable alternative. Between ground and space, lasers are applied in various fields including satellite laser ranging (SLR), laser weapons, and laser communication. However, laser used between the ground and space are significantly influenced by the Earth’s atmosphere. Consequently, understanding the atmospheric effects on laser propagation is crucial. In particular, atmospheric turbulence, which refracts and distorts laser beams, intensifies closer to the Earth’s surface, exerting a greater impact on the uplink than on the downlink. While downlink verification is facilitated by ground detection, verifying the uplink poses challenges due to the necessity of space-based detection. In response to these challenges, we propose the idea of cube satellite as a means to enhance understanding and verification of laser propagation in the uplink. Additionally, we present the results of conceptual design by analyzing requirements, focusing on mission design of the CLUB cube satellite, following the stages of systems engineering for systematic cube satellite development.

Target Diagnostic Systems for Proton, Electron, and X-ray Generation Experiments Based on Ultraintense Laser-Target Interactions

최일우,김형택,Nasr Hafz,유태준,JaeHee Sung,Ku Lee,김철민,IJong Kim,Young-Chul Noh,고도경,Jongmin Lee 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.2

We have designed and constructed various experimental systems to perform interaction experimentswith a 100-TW Ti:sapphire laser and a solid or a gas target, and we have used them forproton, electron, and X-ray generations. They consist of a laser beam delivery system, a targetchamber, a laser focusing and monitoring system, a target manipulation system, and target diagnosticsystems, such as a visible emission imager and an X-ray pinhole camera. The laser beamcan be focused with a peak intensity as large as ~1021 W/cm2 and a focal spot size as small as ~4μm. The solid target is precisely positioned at the laser focus with an accuracy of 20 μm, whichis much smaller than the Rayleigh range of the focused laser beam. The target diagnostic systemsallow us to investigate the status of laser-target interactions with real-time and online operationwhen the laser and the target conditions are optimized to obtain the desired characteristics forthe proton, electron, and X-ray sources. Strong correlations between the images in the diagnosticsystems and monoenergetic electron and higher-energy proton generations are presented.

후두 기공 협착 예방을 위한 청색광 레이저의 적용

표한재,김현수,이예찬,강현욱 한국조명.전기설비학회 2021 조명·전기설비학회논문지 Vol.35 No.5

Stomal stenosis is a narrowing of stoma created by surgical incision and one of the most common complications that exist in patients after tracheostomy. Recently, blue laser light (405 nm) has been suggested as a non-surgical and noninvasive tool for preventing stenosis and scar through cell inactivation. However, the excessive photon energy may lead to irreversible damage in biological tissue due to excessive heat generation. Therefore, the purpose of this study is to numerically assess developments of temperature and thermal damage in a multi-layer tissue during 405 nm laser irradiation for the treatment of the stomal stenosis. The proposed simulation evaluates spatio-temporal changes of temperature induced by the 405 nm laser irradiation at 250, 500, and 1000 mW/cm2 for 300 s in the stomal stenosis model. The simulation results show that the irradiation of 250 mW/cm2 for 300 s increases the temperature of the stomal tissue up to 39.6 °C, which can induce a photochemical response with no or minimal thermal damage. Thus, the proposed bio-heat transfer simulation model can predict the extent of the laser-induced heat generation as well as thermal damage in the stomal tissue. Further studies will examine the identified irradiation condition in an animal model to evaluate a therapeutic capacity of the blue laser light for the prevention of the laryngeal stomal tissue.

Changes in laser-induced thermoelastic effects depending on the position of an absorbing layer in indirect laser stimulation

Yang Seung-Jin,Kim Hyung-Sik,Jun Jae-Hoon,Chung Soon-Cheol,박종락 한국물리학회 2022 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.80 No.4

We studied the laser-induced thermoelastic effects in an elastic medium that can be used for indirect laser stimulation, depending on the position of the absorbing layer. The displacement of the front and rear surface centers of the medium was simulated numerically by solving the heat transfer and thermoelastic wave equations. It was observed that by changing the position of the absorbing layer in the medium, the magnitude and more importantly, the direction of displacement can be controlled. In particular, pushing (displacement into the skin) was expected for an absorbing layer near the rear surface of the medium, whereas pulling (displacement away from the skin) was observed for an absorbing layer near the front surface.

Non-contact Tactile Sensation by Pulsed Laser Stimulation

( Ji Sun Kim ),( Han Byeol Oh ),( A Hee Kim ),( Bong Jun Goh ),( Jun Sik Kim ),( Eun Suk Lee ),( Soon Cheol Chung ),( Jong Rak Park ),( Jae Hoon Jun ) 한국감성과학회 2015 추계학술대회 Vol.2015 No.-

With the development of optical techniques, there is a growing interest in laser applications in biological science and medicine. Laser has the merit that it can be quantitatively delivered to the small area with the desired energy, frequency and pulse width. This merit was utilized to non-contact tactile sensation using laser-induced mechanical effects. Various laser parameters were applied to investigate the effect of these parameters on laser stimulation for tactile sensation. This study showed the possibility of non-contact tactile sensation using laser. The results can be used in laser-induced biostimulation and tactile sensation without tissue damage.

CHANGE OF INDUCED STRESS WAVE ON COLLAGEN TISSUE FOR BIOSTIMULATION BY FREQUENCY-DOUBLED Nd:YAG LASER

OH, HAN-BYEOL,KIM, JI-SUN,JUNG, GU-IN,BAEK, JIN-YOUNG,KIM, JUNGGIL,JUN, JAE-HOON World Scientific Publishing Company 2018 JOURNAL OF MECHANICS IN MEDICINE AND BIOLOGY Vol.18 No.7

<P>In this research, thermoelastic effect was investigated for biostimulation without damage on the biological medium using laser. Thermoelastic effect was generated and mechanical stress was induced by laser irradiation on the collagen, the main protein in the human body, under various conditions with short pulsed laser. The threshold laser energy to induce stress wave in each medium thickness was examined with a piezo sensor. Based on the test, the stimulation strength can be controlled through the adjustment of medium thickness, laser energy and beam diameter. The result implies that precise stimulation with various strengths of stress waves can be generated at the target depth without direct contact with the biological medium. This research can be used valuably in various fields such as contactless biostimulation, low power laser treatment and laser haptic applications.</P>