• Maxillofacial Plastic and Reconstructive Surgery
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• 제40권
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• pp.16.1-16.5
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• 2018

Background: Proliferative verrucous leukoplakia (PVL) is an oral potentially malignant disorder, characterized by multifocal expression, progressive clinical evolution, and a high rate of malignant transformation. Evidence-based information regarding optimal PVL management is lacking, due to the paucity of data. The present report describes a case of PVL associated with HPV-16 infection and epithelial dysplasia treated by diode laser surgery, and the outcome of disease clinical remission over a 2-year follow-up period. Case report: A 61-year-old Caucasian male with oral verrucous hyperkeratosis presented for diagnosis. The lesions were localized on the maxillary gingiva and palatal alveolar ridge. Multiple biopsy specimens have been taken by mapping the keratotic lesion area. Microscopic examination was compatible with a diagnosis of PVL with focal mild dysplasia, localized in the right maxillary gingiva. Polymerase chain reaction (PCR) was done for human papillomavirus (HPV) detection which revealed presence of HPV DNA, and the genotype revealed HPV 16 in the sample. The PVL in the right gingival area was treated on an outpatient basis by excision with a diode laser. This approach resulted in good clinical response and decreased morbidity over a 2-year follow-up period. Conclusions: This case illustrates the benefit of a conservative approach by diode laser treatment than wide surgical excision for management of the PVL lesions associated with mild dysplasia and HPV-16 infection.

• 대한치과교정학회지
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• 제48권2호
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• pp.90-97
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• 2018

Objective: The aim of this study was to assess the analgesic effect of a single application of low-level laser therapy (LLLT) on spontaneous pain and pain on chewing after placement of initial archwires. Methods: Forty-two patients (26 women, 16 men) were randomly recruited for this split-mouth randomized clinical trial. Each patient received super-elastic nickel-titanium (NiTi) initial archwires (0.012, 0.014, 0.016, and 0.018-inch [in]) in the maxilla for leveling and alignment for an interval of 4 weeks between archwires. One side of the mouth was randomly designated as experimental, while the other side served as placebo. After insertion of each archwire, the experimental side was irradiated with a diode laser for 3 seconds each on 5 points facially and palatally per tooth, from the central incisor to first molar. On the placebo side, the laser device was held the same way but without laser application. A numerical rating scale was used to assess the intensity of spontaneous and masticatory pain for the following 7 days. The Mann-Whitney U test was used to compare pain scores between sides. Results: Patients in the LLLT group exhibited significantly lower mean scores for spontaneous pain after insertion of the initial two archwires (0.012-in and 0.014-in NiTi; p < 0.05), while there was no significant difference for 0.016-in and 0.018-in wires between the LLLT and placebo groups. LLLT significantly reduced chewing pain scores (p < 0.05) for all archwires. Conclusions: A single dose of LLLT considerably lessened postoperative pain accompanying the placement of super-elastic NiTi wires for initial alignment and leveling.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1989년도 춘계학술대회
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• pp.9-12
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• 1989

A preliminary study has been conducted to demonstrate the effect of laser heat treatment on Ni Ti alloy dental arch wires ($0.016"\;{\times}\;0.022"$ and $0.018"\;{\times}\;0.026"$, rectangular shape). Changes in mechanical and thermal properties and surface morphologies are investigated by using optical and scanning electron microscope (SEM), energy dispersive x-ray microprobe analysis(EDX), differential scanning calorimeter (DSC), and micro hardness tester. The results indicate that the laser can affect the thermal equilibrium state of the localized surface. Titanium rich surface film is formed by the laser treatment. The surface film and rapidly resolidified underlying structures show better chemical resistance than the matrix material. Phase transition temperatures which are related to shape recovery temperatures are changed after laser treatment. Hardness of resolidified area and heat affected zone are lower than before treatment.

• 대한치과재료학회지
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• 제44권1호
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• pp.33-41
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• 2017

In this study, we prepared PLA-tetracycline complexes coated gold nanoparticle-titania nanotubes and estimated their infrared LASER mediated drug release in the abdominal region of ICR mouse. The results of UV-Vis spectrophotometer showed the highest absorbance at the wavelength of 530 nm and 809 nm indicating the existence of gold nanoparticles. EDX analysis showed that the amounts of gold nanoparticle coated on titania nanotubes were approximately 3.62-36.5 wt%. In vivo test resulted that the tetracycline release value of experimental groups (6.5 ng/mL) was higher than that of control group (5.8 ng/mL) on the condition of 30 minutes of LASER irradiation. Therefore, it is expected that PLA-tetracycline complexes coated gold nanoparticle-titania nanotubes have the feasibility in the field of infrared remote controlled drug device and overcome the limitation of location and time of drug release in dental implant.

• 대한의용생체공학회:의공학회지
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• 제20권2호
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• pp.231-236
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• 1999

Q-switch된 Er:YAG 레이저를 이용해서 치아표면에 뿜어준 외부의 물로 인해 유도된 열 및 역학적인 효과를 이해하는 것은 free-running Er:YAG 레이저에 의한 절삭효과를 이해하는데 대단히 중요하다. 이는 (파장 하나의 길이가 250 $\mu\textrm{s}$인) free-running 레이저에 의한 한 거 대효과가 본 실험에서 이용한 (파장 하나의 길이가 1 $\mu\textrm{s}$인) Q-switch된 레이저에 의한 미소효과들의 축적이기 때문이다. 치아표면에 물이 있을 때 Q-Switch된 레이저에 의한 절삭률은 그렇치 않은 때에 비해 증가되었다. 치아표면에 물을 뿜어주는 횟수는 절삭률에 영향을 미쳐서 저에너지에서는 더디게 물을 뿜어줄때 놀은 절삭률을 얻었다. 반동압력의 세기는 치아표면 조건에 의존하는데. 표면이 젖을수록 그리고 뿜어준 물의 양이 증가 할 수록, 반동압력의 세기 또한 증가하였다. 이 연구로부터 우리는 1-$\mu\textrm{s}$-길이의 pulsed 레이저에 의해 유도된 열 및 역학적인 효과가 외부에 물이 있을 때 free-running Er:YAG 레이저에 의한 절삭을 이해하는데 중요한 정보를 제공해 준다는 것을 알았다.

• 대한치과의사협회지
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• 제47권8호
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• pp.479-486
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• 2009

Purpose: The aim of this study was to show the clinical results of combination of Nd-YAP (1340nm) laser therapy with conventional endodontic and periodontal treatment. Materials and Methods: Four patients with chronic advanced periodontitis and endodontic infection were treated with conventional treatment and Nd-YAP laser therapy. Occlusal adjustment and splinting were done for stabilization of the teeth with severe horizontal and vertical mobility. The protocol for periodontal treatment was followed as scaling and root planing, pocket irrigation with 3% $H_2O_2$ and exposure of Nd-YAP laser using 320${\mu}m$ optical fiber with 160mJ/pluse, 30Hz. The other protocol for endodontic treatment was followed as access opening, canal preparation by hand and rotary instrument, canal filling, and exposure of Nd-YAP laser using 200${\mu}m$ optical fiber with 200mJ/pluse, 10Hz and 180mJ/pluse, 5Hz which were used respectively for disinfection and canal filling. The assessments of probing depth, mobility, and radiography were made prior to and after treatment. Result: All of these four clinical cases showed good healing of periodontium, which presented decrease of mobility and pocket depth, and increase of bone regeneration and bone density on the radiography. Conclusion: The bactericidal effect of Nd-YAP laser would provide benefits for improving clinical results that are obtained from conventional therapy.

• 대한치과기공학회지
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• 제36권4호
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• pp.239-246
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• 2014

Purpose: The purpose of this study was to compare the tensile strength and mechanical properties of orthodontic wire joints made by gas soldering and laser welding, with and without filling material, to identify the effectiveness and potential clinical application of laser welded orthodontic wires. Methods: Three joint configurations of orthodontic wire were used: diameter 0.9 to 0.9 mm wire, diameter 0.9 to 0.5 wire and diameter 0.9 mm wire to band. The joints were made using three different methods: gas soldering, laser welding with and without filling material. For each kind of joint configuration or connecting method 7 specimens were carefully produced. The tensile strengths were measured with a universal testing machine (Zwick/Roell, Instron, USA). The hardness measurements were carried out with a hardness tester(Future-Tech Co. Tokyo, Japan). Data were analyzed by AVOVA(p= .05) and Turkey HD test(p= .05). Results: In all cases, gas soldering joints were ruptured on a low level on tensile bonding strength. Significant differences between laser welding and gas soldering(p< .05) were found in each joint configuration. The highest tensile strength means were observed for laser welding, with filling material, of 0.9 to 0.9 mm wire joint. Conclusion: In conclusion, the elastic modulus and tensile strength means of laser soldering with filling material were the highest, and the tensile strength means of laser soldering were higher than those of gas soldering.

• 대한치과보철학회지
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• 제52권2호
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• pp.67-73
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• 2014

연구 목적: 본 연구의 목적은 주조, 3-D printing laser sintered 및CAD/CAM technology를 이용한 milling 방법으로 제작된 치과용 코발트-크롬 합금의 기계적 물성을 비교하고 파절 단면의 미세 구조를 살펴보는 데 있다. 이를 통해 새롭게 소개된 제작 기법 - 3D-printing laser sintered - 이 치과용 합금 제작으로 적합한 지 알아보고자 한다. 연구 재료 및 방법: 36개의 flat disc 모양의 시편을 제작하여 제작 방법에 따라 세 집단으로 나누었다; 주조 방식으로 제작한 12개, laser sintering 방법으로 12개, CAD/CAM milling 방법으로 12개의 시편을 제작하여 표면 경도 시험을 시행하였다. 또한 각 집단 별로 12개의 dumbbell 모양의 시편을 제작하여 인장 강도 시험을 시행하였다. 통계량이 비모 수적 통계 분포를 보였으므로 Kruskal-Wallis 검정을 이용하여 각 실험군의 인장 강도 시험 결과를 비교했으며, 통계적 유의 수준은P=.05로 설정하여 Mann-Whitney 및 Bonferroni 사후 검정을 시행하였다. 전자 주사 현미경을 사용하여 파절 단면의 미세 구조를 관찰하였다. 결과: Vickers hardness test에서 세 집단간에 모두 유의한 차이가 있었고, 주조 방식으로 제작된 실험군에서 가장 큰 표면 경도(455.88 Hv)가, CAD/CAM milling으로 제작된 실험군에서 가장 낮은 표면 경도(243.40 Hv)를 나타냈다. 최대 인장 강도, 0.2% 항복강도, elongation 및 elastic modulus에서 세 집단간에 모두 유의한 차이가 나타났으며, CAD/CAM milling으로 제작한 실험군에서 가장 높은 최대 인장 강도(1442.94 MPa)가, laser sintered 실험군에서 가장 큰 0.2% 항복 강도(1136.15 MPa)가 나타났다. 파절 단면의 전자 주사 현미경 관찰 결과, 주조 시편에서는 독특한 성긴 모양과 전형적인 주조 다공성 구조가 관찰되었고, laser sintered 시편에서는 편평한 면을 동반한 거친 결정 구조가, 그리고 milled 시편에서는 균일하고 규칙적인 치밀 미세 구조가 나타났다. 결론: 서로 다른 제작 방법은 코발트-크롬 합금의 물리적 성질과 파절 단면의 미세 구조에 영향을 미쳤다. 주조 방식으로 제작된 시편에서 가장 큰 표면 경도가, milling으로 제작된 시편에서 가장 큰 인장 강도를 나타냈으며, 본 연구의 모든 실험군에서 치과용 합금의 ISO 기준에 부합하는 물성을 보였다.

• 대한치과보철학회지
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• 제37권2호
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• pp.256-268
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• 1999

Submerged implants require secondary surgical uncovering of implants after healing period of 3-6 months. In surgical methods, there are surgical scalpel, tissue punch, electro-surgical, and laser-used uncovering, and so forth The objectives of this study are investigation and assessment of 1) thermal change in clinical application for uncovering of HA-coated implant and pure titanium implant irradiated by pulsed Nd-YAG, $CO_2$, and Er-YAG laser. 2) surface change of cover screws aaer irradiation using laser energy. The temperature of apex & side wall of implants were recorded at 10sec, 20sec, 30sec after 30sec irradiation to implant healing screw; 1) pulsed Nd-YAG laser; 2W, 20pps, contact mode 2) $CO_2$ laser; water-infused & non-water infused state, 2.5-3.5W, contibuous mode, noncontact mode 3) $CO_2$ laser ; non-water infused state, 3W, superpulse, noncontact. mode 4) Er-YAG laser; (1) non-water infused state, 10pps, 60mj, contact mode (2) water-infused state, 10pps, 60mj, 80mj, 101mj, contact mode. According to the results of this study, pulsed Nd-YAG laser is not indicated because of increased thermal change and pitting of metal surface of implant cover screw. By contrast, $CO_2$ laser & Er-YAG laser are presumed to indicate because of narrow range of thermal change & near abscence of thermal damage of metal surface. Dental laser is thought to be much helpful to surgical procedure when it is used as optimal power and time condition considering characteristics and indications of each laser. Further research is needed to verify that these techniques are safe and beneficial to implant success.

• 대한소아치과학회지
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• 제30권1호
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• pp.153-160
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• 2003

연구의 목적은 이산화탄소 레이저의 유치 법랑질 탈회 억제 및 재경화 효과를 레이저형광측정법을 사용하여 평가하는 것이었다. 사람 유치의 건전 평활면으로부터 법랑질 시편을 제작하여, 코카콜라에 담가 24시간 탈회시키는 전후에 정촛점 연속파 또는 탈촛점 펄스파, 3W 또는 6W로 4초간 직경 약 2 mm의 조사점에 이산화탄소 레이저를 조사하고, Diagnodent 측정을 통하여 탈회억제효과와 재경화 효과를 평가하였다. 탈회된 법랑질에 대한 정촛점 연속파 또는 탈촛점 펄스파 조사의 재경화 효과는 두 군 사이에 유의한 차이가 없었으며 모두 탈회 전과 유의한 차이가 없는 수준으로 감소하였다. 건전 법랑질에 대한 3W 또는 6W 탈촛점 펄스파 조사의 탈회 억제 효과에서 3W군은 탈회 후의 측정치가 유의하게 증가하였고(P<0.05), 6W군은 탈회 후 유의한 증가가 없었다. 탈회된 법랑질에 대한 3W또는 6W 탈촛점 펄스파 조사의 재경화 효과에서 3W군은 레이저 조사 후 유의하게 감소하였으나 탈회 전보다 유의하게 컸고(P<0.05), 6W군은 레이저 조사 후 유의하게 감소하였고(P<0.05) 탈회 전과 유의한 차이가 없었다(P>0.05). 유치 법랑질의 색은 6W로 탈회 후 조사하였을 때 갈색 내지 검은색으로 변색되었고 탈회 전 조사하였을 때 갈색으로 변색되었으며, 탈회 전과 후에 3W로 조사하였을 때에는 색의 변화가 없었다.