• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.1085-1087
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• 2002

Deformation of soft tissue is known inhomogeneous and non-linear in general. In this study, we propose a measurement methodology of local/global strain during soft tissue elongation precisely using laser extensometer which has high accuracy, resolution and is possible to measure global/local strain. The mechanical tensile test are performed on tibialis cranialis, flexor hallucis longus, extensor digitorum longus of swine hindlimb. In order to measure target displacement, reflective marker is attached to detect elongation on specimen using surgical adhesive. The result of this study is to show that laser extensometer is valid to measure longitudinal elongation which is inhomogeneous and non-linear fur soft tissue.

• Journal of Oral Medicine and Pain
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• 제35권3호
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• pp.177-182
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• 2010

구강 내 연조직 소수술 시, 수술도, 열 요법, 전기요법, 한냉요법 등은 현재까지 사용되고 있는 고전적인 수술법이다. 하지만 이들 통상적인 수술적 방법의 문제로 멸균 상태의 유지, 공간의 제한, 출혈, 창상 치유의 문제, 흉터, 전신질환에 의한 수술의 제한 등이 있다. 최근 레이저가 또 하나의 수술법으로 널리 사용되고 있고, 통상적인 외과적 수술법에 비하여 레이저의 장점으로는 멸균상태 유지, 출혈감소, 통증 감소, 창상의 치유 촉진, 반흔 생성 억제 등이 있다. 특히 탄산가스 레이저는 조직 내수분에 최대한으로 흡수되어 $100{\mu}m$ 정도의 낮은 침투도를 가지며, 주변부 모세 혈관을 응고시켜 구강 내 소수술에 적용 시우수한 지혈 효과 및 수술 시야의 확보를 얻을 수 있다.

• 대한소아치과학회지
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• 제30권1호
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• pp.116-123
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• 2003

소아 환자에서 외과적 처치 후 많은 불편감과 동통이 존재한다. 최근 몇몇의 연구에서 저출력 레이저의 조사로 구강내 창상의 치유 과정이 촉진된다는 보고가 있다. 이에 본 증례에서는 외과적 처치 후 저출력 레이저조사가 연조직의 치유 과정에 미치는 영향을 알아보고자 과잉치 발거와 설소대 절단술을 시행하고, 저출력 레이저(DENS-BIO Laser)를 pulse 8(1000Hz), 2mW의 조사조건으로 4분간 조사 후 그 연조직 창상 치유 양상을 관찰하여 다음과 같은 결과를 얻을 수 있었다. 1. 레이저를 조사한 부위가 레이저를 조사하지 않은 부위보다 빠르게 치유되었다. 2. 레이저 조사한 경우 환자는 술 후 동통을 덜 호소하였다.

• Restorative Dentistry and Endodontics
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• 제22권2호
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• pp.519-535
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• 1997

The responses of human pulp fibroblastic cells to Ga-As Semi-Conductor-Dens-Bio Laser (Frequency: 5 Hz~10,000 Hz Model: SD-101A RCA, U.SA)) were examined in vitro using pulp fibroblastic cells obtained from the pulp tissue of human tooth. The mitogenic effect of soft laser was assessed by measuring the MTT assay. The morphologic effect for soft laser showed under the scanning and transmission electron microscopy. The results as follows; 1. The mitogenic response of the soft laser was not observed until 4th time of radiation, while the mitogenic response at 4th time increased mitogenic effect by as much as 1.7 fold compared to the control value. 2. The mitogenic response of the soft laser on pulp fibroblast differ from the mitogenic response on other fibroblasts. 3. In scanning electron microscopic study, The microvilli of cell surface increased gradually with width and length after laser radiation, it demonstrate that development of microvilli have close connection with differentiation of cells. 4. Under the transmission electron microscope, The laser-treated cells maintained their elongated shape and a high degree of cellular polarization. The large cell body containing a well developed Golgi complex, a large number of profiles of rough endoplasmic reticulum, and great numbers of mitochondria. 5. The laser-treated cells maintained the long straight bundles of closely apposed microfilaments or individual filaments forming a cross-linked network. These findings suggest that the laser may have important roles in promotion of pulp healing and consequently may be useful for clinical application in pulp regenerative procedures.

• Journal of Periodontal and Implant Science
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• 제32권3호
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• pp.615-630
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• 2002

Various long-term studies have shown that titanium implants as abutments for different types of prostheses have become a predictable adjunct in the treatment of partially or fully edentulous patients. The continuous exposure of dental implants to the oral cavity with all its possible contaminants creates a problem. A lack of attachment, together with or caused by bacterial insult, may lead to peri-implantitis and eventual implant failure. Removal of plaque and calculus deposits from dental titanium implants with procedures and instruments originally made for cleaning natural teeth or roots may cause major alterations of the delicate titanium oxide layer. Therefore, the ultimate goal of a cleaning procedure should be to remove the contaminants and restore the elemental composition of the surface oxide without changing the surface topography and harming the surrounding tissues. Among many chemical and mechanical procedure, air-powder abrasive have been known to be most effective for cleaning and detoxification of implant surface. Most of published studies show that the dental laser may be useful in the treatment of pen-implantitis. $CO_2$ laser and Soft Diode laser were reported to kill bacteria of implant surface. The purpose of this study was to obtain clinical guide by application these laser to implant surface by means of Non-contact Surface profilometer and X-ray photoelectron spectroscopy(XPS) with respect to surface roughness and atomic composition. Experimental rough pure titanium cylinder models were fabricated. All of them was air-powder abraded for 1 minute and they were named control group. And then, the $CO_2$ laser treatment under dry, hydrogen peroxide and wet condition or the Soft Diode laser treatment under Toluidine blue O solution condition was performed on the each of the control models. The results were as follows: 1. Mean Surface roughness(Ra) of all experimental group was decreased than that of control group. But it wasn't statistically significant. 2. XPS analysis showed that in the all experimental group, titanium level were decreased, when compared with control group. 3. XPS analysis showed that the level of oxygen in the experimental group 1, 3($CO_2$ laser treatment under dry and wet condition) and 4(Soft Diode laser was used under toluidine blue O solution) were decreased, when compared with control group. 4. XPS analysis showed that the atomic composition of experimental group 2($CO_2$ laser treatment under hydrogen peroxide) was to be closest to that of control group than the other experimental group. From the result of this study, this may be concluded. Following air-powder abrasive treatment, the $CO_2$ laser in safe d-pulse mode and the Soft Diode laser used with photosensitizer would not change rough titanium surface roughness. Especially, $CO_2$ laser treatment under hydrogen peroxide gave the best results from elemental points of view, and can be used safely to treat peri-implantitis.

• Journal of the Korean Physical Society
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• 제73권12호
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• pp.1834-1839
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• 2018

A tabletop ultrafast soft x-ray has been generated from the laser-produce plasma with a femtosecond pulsed Ti:Sapphire laser. The estimated total flux of Al $K{\alpha}$ is of $2.2{\times}10^9photons/sec$ in $4{\pi}$ radian and the parameters related to the optical performance were obtained. The tungsten/silicon multilayer, flat quartz and bent thallium acid phthalate (TLAP) crystal were used for monochromatization of soft x-ray to refine the aluminum $K{\alpha}$ radiation and compared the respective value of $E/{\Delta}E$. To estimate the size of the x-ray source beam generated by a fs laser, the approximation using the FWHM obtained from the x-ray beam scan near the focal point was discussed, and the size of the diameter was about $9.76{\mu}m$.

• 한국레이저가공학회지
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• 제15권2호
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• pp.1-5
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• 2012

Gelatin is used as a model for soft biological tissues in studying laser interaction with the soft tissues. In this work, we analyze the interaction between gelatin and excimer and Ti:Sapphire femtosecond laser under various conditions, especially by varying the laser, laser fluence and pulse number. The results show that swelling of the surface and ablation depth can be controlled by adjusting the process parameters.

• Journal of Dental Anesthesia and Pain Medicine
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• 제23권4호
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• pp.229-236
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• 2023

Background: Local anesthesia has been reliably used to control pain during dental procedures and is important in pediatric dentistry. However, children occasionally complain of prolonged numbness after dental treatment, leading to several problems. Studies conducted to reverse the effect of local anesthesia using phentolamine mesylate and photobiomodulation therapy (PBM) are encouraging but limited. PBM is a type of light therapy that utilizes visible and near-infrared non-ionizing electromagnetic spectral light sources. Hence, this study used this modality to compare the reversal of local anesthesia at two different wavelengths. This study compared the effect of PBM at 660 and 810 nm wavelengths on the reversal of soft tissue local anesthesia using a diode LASER in pediatric dentistry. Method: Informed consent and assent were obtained, and the participants were then divided randomly into three groups of 20 children each: control group-without LASER irradiation, LASER irradiation at 660 nm, and LASER irradiation at 810 nm. Sixty children aged 4-8 years with deciduous mandibular molars indicated for pulp therapy were administered an inferior alveolar nerve block. After 45 min of injection, a duration that was similar to the approximate duration of treatment, they were exposed to 660- and 810-nm LASER irradiation according to their groups until reversal of local anesthesia was achieved. The control group did not undergo LASER irradiation. The reversal of the soft tissue local anesthetic effect was evaluated using palpation and pin prick tests every 15 min, and the LASER irradiation cycle continued until reversal of the soft tissue local anesthesia was achieved. Results: A significant reduction of 55.5 min (27.6%) in the mean soft tissue local anesthesia reversal time was observed after the application of 810 nm wavelength PBM and 69 min (34.7%) after 660 nm wavelength LASER irradiation. Conclusion: PBM with a 660 nm wavelength was more effective in reducing the mean soft tissue local anesthesia reversal duration, and thus can be used as a reversal agent for soft tissue local anesthesia in pediatric dentistry.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.690-693
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• 2003

Soft x-ray microscopy provides a unique set of capabilities in-between those of visible light and electron microscopy. It has long been recognized that nature provides a 'water window' spectral region between the K shell x-ray absorption edges of carbon (~290eV) and oxygen (~540eV), where organic materials show strong absorption and phase contrast, while water is relatively non-absorbing. This enables imaging of hydrated biological specimens that are several microns thick with high intrinsic contrast using x-rays with a wavelength of 2.3~4.4nm. Soft X-ray microscopy is therefore well suited to the study of specimens like single biological cells. The most direct advantage of X-ray microscope is their high spatial resolution when compared with visible light microscopes, combined with an ability to image hydrated specimens that are several microns with a minimum of preparation. Our study describes the conceptual design of soft x-ray microscope system based on a laser-based source for biomedical application with high resolution ($\leq$50nm) and short exposure time ($\leq$30sec).

• Journal of Periodontal and Implant Science
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• 제31권2호
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• pp.451-463
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• 2001

Following the extensive use of implant, the incidence of peri-implantitis increases. Guided bone regeneration has been used for the optimal treatment of this disease. Because implant surface was contaminated with plaque and calculus, cleaning and detoxification were needed for the reosseointegration when guided bone regeneration was performed. Various mechanical and chemical methods have been used for cleaning and detoxification of implant surface, air-powder abrasive and oversaturated citrate were known to be most effective among these methods. However, these methods were incomplete because these could not thoroughly remove bacteria of implant surface, moreover deformed implant surface. Recent studies for detoxification of the implant surface using laser were going on, $CO_2$ laser and Soft Diode laser were known to be effective among these methods. The purpose of this study was to obtain clinical guide by application these laser to implant surface. 15 experimental machined pure titanium cylinder models were fabricated. The $CO_2$ laser treatment under dry, wet and hydrogen peroxide condition or the Soft Diode laser treatment under Toluidine blue O solution condition was performed on the each of models. Each groups were examined with SPM and SEM to know whether their surface was changed. The results were as follows : 1. Surface roughness and surface form weren't changed when $CO_2$ laser was usedunder dry condition(P>0.05). 2. Surface roughness and surface form weren't changed when $CO_2$ laser was used under wet condition(P>0.05). 3. Surface roughness and surface form weren't changed when $CO_2$ laser was used under hydrogen peroxide condition(P>0.05). 4. Surface roughness and surface form weren't changed when Soft Diode laser was used under toluidine blue O solution condition(P>0.05). From the result of this study, it may be concluded that the $CO_2$ laser having relatively safe pulse mode and the Soft Diode laser used with photosensitizer can be used safely to treat peri-implantitis.