• Imaging Science in Dentistry
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• v.51 no.2
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• pp.107-115
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• 2021

Purpose: This study aimed to demonstrate the presence of dental caries through a photoacoustic imaging system with visible and near-infrared wavelengths, highlighting the differences between the 2 spectral regions. The depth at which carious tissue could be detected was also verified. Materials and Methods: Fifteen permanent molars were selected and classified as being sound or having incipient or advanced caries by visual inspection, radiography, and optical coherence tomography analysis prior to photoacoustic scanning. A photoacoustic imaging system operating with a nanosecond pulsed laser as the light excitation source at either 532 nm or 1064 nm and an acoustic transducer at 5 MHz was developed, characterized, and used. En-face and lateral(depth) photoacoustic signals were detected. Results: The results confirmed the potential of the photoacoustic method to detect caries. At both wavelengths, photoacoustic imaging effectively detected incipient and advanced caries. The reconstructed photoacoustic images confirmed that a higher intensity of the photoacoustic signal could be observed in regions with lesions, while sound surfaces showed much less photoacoustic signal. Photoacoustic signals at depths up to 4 mm at both 532 nm and 1064 nm were measured. Conclusion: The results presented here are promising and corroborate that photoacoustic imaging can be applied as a diagnostic tool in caries research. New studies should focus on developing a clinical model of photoacoustic imaging applications in dentistry, including soft tissues. The use of inexpensive light-emitting diodes together with a miniaturized detector will make photoacoustic imaging systems more flexible, user-friendly, and technologically viable.

• The Journal of Advanced Prosthodontics
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• v.14 no.5
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• pp.305-314
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• 2022

PURPOSE. The aim of this study was to evaluate the flexural strength of a 3D-printed denture base resin (Cosmos Denture), after different immediate repair techniques with surface treatments and thermocycling. MATERIALS AND METHODS. Rectangular 3D-printed denture base resin (Cosmos Denture) specimens (N = 130) were thermocycled (5,000 cycles, 5℃ and 55℃) before and after the different repair techniques (n = 10 per group) using an autopolymerized acrylic resin (Jet, J) or a hard relining resin (Soft Confort, SC), and different surface treatments: Jet resin monomer for 180 s (MMA), blasting with aluminum oxide (JAT) or erbium: yttrium-aluminum-garnet laser (L). The control group were intact specimens. A three-point flexural strength test was performed, and data (MPa) were analyzed by ANOVA and Games-Howell post hoc test (α = 0.05). Each failure was observed and classified through stereomicroscope images and the surface treatments were viewed by scanning electron microscope (SEM). RESULTS. Control group showed the highest mean of flexural strength, statistically different from the other groups (P < .001), followed by MMA+J group. The groups with L treatment were statistically similar to the MMA groups (P > .05). The JAT+J group was better than the SC and JAT+SC groups (P < .05), but similar to the other groups (P > .05). Adhesive failures were most observed in JAT groups, especially when repaired with SC. The SEM images showed surface changes for all treatments, except JAT alone. CONCLUSION. Denture bases fabricated with 3D-printed resin should be preferably repaired with MMA+J. SC and JAT+SC showed the worst results. Blasting impaired the adhesion of the SC resin.

• Journal of Oral Medicine and Pain
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• v.23 no.2
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• pp.101-108
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• 1998

본 연구는 두 가지 관점, 즉 다이오드레이저를 구강연조직에 접촉식으로 조사하여 조직을 절제할 경우 첫째 심부조직에서의 온도 상승 정도에 대한 분석 평가, 둘째 절제에 따른 조직의 열적 응고에 대한 조직학적 분석 평가를 위해 시도되었다. 연구를 위해 도축된 소의 혀 배면으로부터 5.0mm깊이에 T형 열전대(type T thermocouple)를 설치하고 조사조건에 따른 레이저절제 도주의 온도변화를 측정하고, 또한 해당조사부위의 조직을 대상으로 통법에 의한 H-E염색 후 조직학적 측면에서 열적 응고상을 검색하여 Nd:YAG레이저의 경우에서와 비교하였다. 즉 파장815nm의 다이오드레이저를 0-10W의 출력, 50Hz와 연속파의 주파수조건에서 접촉식으로 조사하였으며, 또한 파장1064nm의 Nd:YAG레이저를 0-10W의 출력, 50Hz와 100Hz의 주파수 조건에서 접촉식으로 조사하였다. 레이저의 접촉조사시 레이저광섬유 첨단부에서 10(10gm의 일정한 압력과 25mm/sec의 이동속도로 조직을 절제하였다. 레이저가 접촉조사된 조직부위를 통법에 의해 조직학적으로 H-E염색을 시행하였으며, 계측현미경을 이용하여 10배율 아래에서 조직절제의 폭과 깊이, 측방 및 하방 쪽으로 열적 응고의 폭을 계측하였다. 계측치에 대한 통계학적 처리결과 조직절제의 폭과 측방쪽으로 열적응고의 폭은 다이오드레이저에와 Nd:YAG레이저에서 같은 정도를 나타냈다. 조직절제의 깊이는 Nd:YAG레이저에서에 비해 다이오드레이저에서 더 깊었다. 하방쪽으로의 열적응고의 폭은 Nd:YAG레이저를 10Hz의 조건에서 조사한 경우에서 가장 넓었으며, 다이오드레이저를 50Hz와 연속파의 조건에서 조사한 경우에서 가장 좁았다. 레이저절제 도중 심부조직에서의 온도변화는 다이오드 레이저에서와 Nd:YAG레이저에서 모두 출력이 증가함에 따라 상승되었으며, 다이오드레이저에서 보다 Nd:YAG레이저에서 더 높이 상승되었다. 결론적으로 본 연구에서 시도된 조사조건 범위 이내에서는 구강연조직 절제시 다이오드레이저가 펄스형 광섬유 전달식 Nd:YAG레이저 보다 심부조직에서의 낮은 온도상승과 하방쪽으로의 좁은 열적 응고의 폭을 보이면서 우수한 조직절제효과를 나타냈다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4D
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• pp.555-561
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• 2009

In lieu of section profile data, a fitting of the bored tunnel shape is more significant confirmation for maintenance of a tunnel. Before the permit on the completion of a tunnel, deformation of the completed tunnel with respect to the design model are considered. And deformation can be produced at continuously along the entire of the tunnel section. This study firstly includes an analysis of algebraic approach and test it with an observed field data. And then a number of methods, line search method, genetic algorithm, and pattern search methods, are compared with the 3D tunnel shape fitting. Algebraic methods can solve a simple circular cylinder type as like a railway tunnel. However, a more complex model (compound circular curve and non circular) as like a highway tunnel has to be solved with soft computing tools in the cause of conditional constraints. The genetic algorithm and pattern search methods are computationally more intensive, but they are more flexible at a complex condition. The line search method is fastest, but it needs a narrow bounds of the initial values.

• Journal of dental hygiene science
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• v.23 no.4
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• pp.369-377
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• 2023

Background: In this study, we investigated the potential use of keratin for oral tissue regeneration. Keratin is well-known for its effectiveness in skin regeneration by promoting keratinization and enhancing the elasticity and activity of fibroblasts. Because of its structural stability, high storability, biocompatibility, and safety in humans, existing research has predominantly focused on its role in skin wound healing. Herein, we propose using keratin proteins as biocompatible materials for dental applications. Methods: To assess the suitability of alpha-keratin protein as a substrate for cell culture, keratin was extracted from human hair via PEGylation. Viabilities of primary human gingival fibroblasts (HGFs) and human oral keratinocytes (HOKs) were assessed. Fluorescence immunostaining and migration assays were conducted using a fluorescence microscope and confocal laser scanning microscope. Wound healing and migration assays were performed using automated software to analyze the experimental readout and gap closure rate. Results: We confirmed the extraction of alpha-keratin and formation of the PEG-g-keratin complex. Treatment of HGFs with keratin protein at a concentration of 5 mg/ml promoted proliferation and maintained cell viability in the test group compared to the control group. HOKs treated with 5 mg/ml keratin exhibited a slight decrease in cell proliferation and activity after 48 hours compared to the untreated group, followed by an increase after 72 hours. Wound healing and migration assays revealed rapid closure of the area covered by HOKs over time following keratin treatment. Additionally, HOKs exhibited changes in cell morphology and increased the expression of the mesenchymal marker vimentin. Conclusion: Our study demonstrated the potential of hair keratin for soft tissue regeneration, with potential future applications in clinical settings for wound healing.

• Journal of Oral Medicine and Pain
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• v.35 no.4
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• pp.245-258
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• 2010

Smoking has been identified not as a major risk factor for circulatory and respiratory diseases but also as causes of various oral diseases. A number of clinical studies and regional health surveys have found an association between smoking and poor oral health status and between smoking and prognosis of dental treatments. However, there is few studies about status of smoking cessation treatment and policies in dentistry in Korea. The purpose of this study was to investigate the smoking patterns of outpatients and outcomes of short-term smoking cessation treatment in dental hospitals in Korea and, subsequently, to seek further smoking cessation services in dentistry. This study was sponsored by Korean Dental Association (KDA) and department of culture and welfare. 825 dental patients were voluntarily participated in a 4-week smoking cessation program with nicotine patch and 297 participants of them completed on smoking-related questionnaires. All participants were recruited from outpatients of 11 dental university hospitals (primarily in the department of oral medicine, oral surgery and periodontology) in Korea during 3-month period from October 2009 to January 2010. The Questionnaires included demographics, duration of smoking, heavy smoking index (HSI), number of thinking of quit smoking, duration of stop smoking and reasons to smoking, awareness of smoking effects on oral health, and their success rate after 4 weeks of nicotine patch program was investigated. The statistical analysis was carried by SPSS version 18.0 program and Chi-square test. According to the results of this study, male in their 30s to 50s were the most prevalent of all the participants and duration of smoking increased with age. Attempt rate to quit smoking (Quit smoking) was the highest in 30s and 40s with duration of quit smoking ranging 1 to 3 months. Emotional stresswas the most frequently reported reason for smoking, followed by habit and pleasure in order. All age group showed high HIS over 71% and awareness of smoking effects on oral diseases such as oral soft tissue diseases, periodontal diseases and dental caries was found relatively high (50~60%) Periodontal implant was the main reason for participation in the smoking cessation services in dental clinics and the success rate of, 4-week nicotine patch program of all the participants was 29.4%, extremely low compared to that of medical clinics. Systemic education for dentists to be able to provide interventions to quit smoking including counseling with the 5As'and development of available measures for smokers is needed as considered that the low success rate of the smoking cessation services in dentistry could be explained mainly by lack of dentists' strategies, experience and attention. Awareness and attention of dentists should be emphasized and their participation be encouraged by long-term, multidisciplinary policies such as establishment of insurance fee, which would made a considerable progress in preventing smoking-related oral diseases and promoting public oral health.

• Journal of Periodontal and Implant Science
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• v.29 no.2
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• pp.415-433
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• 1999

Implant stability is the key to long-term successful outcome for osseointegrated implants. To evaluate the initial healing response of bone around HA-coated implants without primary bone contact. 21 HA-coated thread type implants(STERI-OSS?) were placed in the femurs of 5 mongrel dogs, about 1-year old. Implants, 8 mm in length and 3.8mm(experimental 1group), 5.0mm(experimental 2group) and 6.0mm(control group) in diameter, were inserted after 3 holes of 6.0mm in diameter and 10mm in depth were prepared in the surgical sites each dog. Implants were supported by only nonresorbable membrane($Teflon^{(R)}$), in order to prevent the ingrowth of upper soft tissue into the gap between bone and implant, and to maintain each implant to be positioned in the center of the drilled hole. 9 implants with different diameters were inserted in 3 dogs for histologic observation, and 12 implants were inserted in 2 dogs for mobility test and removal torque test. Fluorescent dyes were injected for the observation of new bone formation in order of $Terramycin^{(R)}$, Arizarin $Red^{(R)}$, and $Calcein^{(R)}$ at an interval of 2 weeks. 3 dogs were sacrificed for histologic observation at 4, 8, and 12-week after placement. Light microscopy and confocal laser scanning microscopy were used to qualitatively characterize the bone around HA-coated implant. 2 dogs were sacrificed for mobility test($Periotest^{(R)}$, Simens AG, Bensheim, Germany) and removal torque test($Autograph^{(R)}$ AGS-1000D series, Japan) at 8 and 12-week after placement The results were as follows: 1. Histologic observation showed that osseointegration occurred to both control and experimental groups as time lapse, but delayed bone healing was revealed in 3.8mm group (experimental 1group), compared to contrtol group and 5.0mm group (experimental 2group). 2. The mobility test showed that the experimental groups had no distinguishable movement during experimental periods of 8 and 12-week, and there was no difference in mobility depending on the gap between bone and implant, and time lapse. 3. The removal torque forces were increased depended on the gaps decreasing between bone and implant, and time lapse. The results suggest that HA-coated implant without primary bone contact, based on guided bone regeneration could obtain its stability in all experimental groups as time lapse, but bone healing was delayed in experimental group of 3.8mm. And the results suggested that studies on correlationship between mobility test and removal torque test for implant stability would be necessary.

• Journal of Korean Neurosurgical Society
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• v.29 no.1
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• pp.35-43
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• 2000

Objective : Percutaneous lumbar approaches such as arthroscopic discectomy, laser discectomy, and nucleotome remain controversial and have technical limitations to free fragment disc, bony pathology and access to L5-S1, The purpose of this study was to determine efficacy of this new endoscopic system and to report techniques and tactics. Methods : From July 1997 to May 1998, we treated 40 consecutive patients(43 levels) with the MED system. Mean age was 32 years(range ; 18 to 62). There were 30 males and 10 females. All patients had sciatica with SLRT limitation. There were 23 patients with disc herniation at L4-5 and 14 patients at L5-S1. Three patients had 2 level disc herniations. There was one far lateral disc herniation at L4-5. Results : Using modified MacNab criteria, there were 37 excellent results and 3 good result. Most patients were discharged within 3-4 days except 2 patients with dural tearing. There were no other complications. Mean operation time was 1.5 hours(range : 40 minutes to 2.5 hours). Conclusion : The MED system is a reliable approach to lumbar disc herniations. This system combines the advantages of conventional open surgery and a minimally invasive technique. As tactics for the doctors who wish to attempt, "palpate" the lamina by first dilator, identification of interlaminar space by removal of overlying soft tissue and confirmation of the shoulder portion of nerve root before discectomy are important to this procedure. We conclude that lumbar disc herniations can be successfully treated with MED approach.

• Archives of Plastic Surgery
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• v.42 no.5
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• pp.552-558
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• 2015

Background The Klippel-Trenaunay syndrome (KTS) is characterized by three clinical features, namely cutaneous capillary malformations, venous malformations, and soft tissue and/or bony hypertrophy of the extremities. The varied manifestations are attributed to the unpredictable clinical nature and prognosis of the syndrome. To elucidate the clinical characteristics of this disease, we reviewed a relatively large number of KTS patients who presented to our vascular anomalies center. Methods We conducted a retrospective study with 19 patients who were diagnosed with KTS and treated in our vascular anomalies clinic between 2003 and 2014, and examined their demographic characteristics, their clinical features, and the treatments administered. Results The sex distribution was balanced, with 9 (47%) males and 10 (53%) females. The mean follow-up period was 4.1 years (range, 7 months-9 years). Most of the patients received conservative treatments such as medication or physiotherapy. Compression therapies such as wearing of elastic garments/bandages were also administered, and surgical interventions were considered only when the patients became excessively symptomatic. Other treatments included laser therapy and sclerotherapy, and all the treatments were adjusted according to each case, tailored to the conditions of the individual patients. Conclusions KTS is an extremely rare, multifactorial disorder that induces widely varied symptoms. Because of this unique feature, plastic surgeons, when not careful, tend to attach a one-sided importance to typical symptoms such as limb hypertrophy or capillary malformation and thus overlook other symptoms and clinical features. KTS can be suspected in all infants who show capillary malformations or limb hypertrophy and require a multi-disciplinary approach for comprehensive management.