• Journal of Yeungnam Medical Science
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• 제25권2호
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• pp.108-116
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• 2008

Background : When surgeons plan mandible ortho surgery for patients with skeletal class III facial asymmetry, they must be consider the exact method of surgery for correction of the facial asymmetry. Three-dimensional (3D) CT imaging is efficient in depicting specific structures in the craniofacial area. It reproduces actual measurements by minimizing errors from patient movement and allows for image magnification. Due to the rapid development of digital image technology and the expansion of treatment range, rapid progress has been made in the study of three-dimensional facial skeleton analysis. The purpose of this study was to conduct 3D CT image comparisons of mandible changes after mandibular surgery in facial asymmetry patients. Materials & methods : This study included 7 patients who underwent 3D CT before and after correction of facial asymmetry in the oral and maxillofacial surgery department of Yeungnam University Hospital between August 2002 and November 2005. Patients included 2 males and 5 females, with ages ranging from 16 years to 30 years (average 21.4 years). Frontal CT images were obtained before and after surgery, and changes in mandible angle and length were measured. Results : When we compared the measurements obtained before and after mandibular surgery in facial asymmetry patients, correction of facial asymmetry was identified on the "after" images. The mean difference between the right and left mandibular angles before mandibular surgery was $7^{\circ}$, whereas after mandibular surgery it was $1.5^{\circ}$. The right and left mandibular length ratios subtracted from 1 was 0.114 before mandibular surgery, while it was 0.036 after mandibular surgery. The differences were analyzed using the nonparametric test and the Wilcoxon signed ranks test (p<0.05). Conclusion: The system that has been developed produces an accurate three-dimensional representation of the skull, upon which individualized surgery of the skull and jaws is easily performed. The system also permits accurate measurement and monitoring of postsurgical changes to the face and jaws through reproducible and noninvasive means.

• 치위생과학회지
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• 제16권5호
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• pp.349-354
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• 2016

2015년 실시한 국민구강실태조사에 따르면 우리나라 만 12세 아동들의 우식경험영구치지수(DMFT index)는 1.9로 주요 OECD 국가들의 평균인 1.6에 거의 근접한 것으로 조사되었다. 본 연구의 목적은 인접면 우식증의 진단에 있어 새로 개발된 $Qraypen^{TM}$의 효능을 기존의 방법인 시진 및 구내 치근단 방사선 사진과 비교 평가하고, 임상 적용 시의 문제점을 파악하여 차후 $Qraypen^{TM}$에 필요한 개선안을 제시함과 아울러 치아우식증의 예방 및 초기 우식증 재광화 방법에 대한 기초 연구자료를 마련하고자 하였다. 학교 구강검진을 목적으로 내원한 학령기의 혼합치열을 가진 32명의 어린이들을 대상으로 구강검진 2회, 구치부 치근단 방사선 필름 판독 2회 그리고 구치부 인접면 $Qraypen^{TM}$ 이미지 판독 2회를 실시하고 비교한 결과 $Qraypen^{TM}$ 영상은 변연융선이 파괴되지 않은 유구치의 인접면 우식증의 탐지에 효과적이었다. 또한 방사선 촬영 결과와 비교해 보니 차이가 없음을 확인하였다. 그러나 인접면 우식증이 상아질까지 진행되어 병소가 성숙하여야 뚜렷한 붉은색 형광을 관찰할 수 있었기에 우식 병소의 진행 정도와 붉은색 형광 발생의 관련성을 확인하기 위해서는 향후 발치된 치아를 사용하여 조직학적 검사를 병행한 추가적인 연구가 필요할 것으로 생각된다. 본 연구 결과 $Qraypen^{TM}$은 유구치의 육안으로 보이지 않은 인접면 우식증을 탐지하는 데 도움을 줄 수 있는 유용하고 간편한 보조장비가 될 수 있을 것으로 기대된다.

• The Korean Journal of Physiology and Pharmacology
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• 제21권4호
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• pp.371-376
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• 2017

The caudal subnucleus of the spinal trigeminal nucleus (medullary dorsal horn; MDH) receives direct inputs from small diameter primary afferent fibers that predominantly transmit nociceptive information in the orofacial region. Recent studies indicate that reactive oxygen species (ROS) is involved in persistent pain, primarily through spinal mechanisms. In this study, we aimed to investigate the role of xanthine/xanthine oxidase (X/XO) system, a known generator of superoxide anion ($O_2{^-}$), on membrane excitability in the rat MDH neurons. For this, we used patch clamp recording and confocal imaging. An application of X/XO ($300{\mu}M/30mU$) induced membrane depolarization and inward currents. When slices were pretreated with ROS scavengers, such as phenyl N-tert-butylnitrone (PBN), superoxide dismutase (SOD), and catalase, X/XO-induced responses decreased. Fluorescence intensity in the DCF-DA and DHE-loaded MDH cells increased on the application of X/XO. An anion channel blocker, 4,4-diisothiocyanatostilbene-2,2-disulfonic acid (DIDS), significantly decreased X/XO-induced depolarization. X/XO elicited an inward current associated with a linear current-voltage relationship that reversed near -40 mV. X/XO-induced depolarization reduced in the presence of $La^{3+}$, a nonselective cation channel (NSCC) blocker, and by lowering the external sodium concentration, indicating that membrane depolarization and inward current are induced by influx of $Na^+$ ions. In conclusion, X/XO-induced ROS modulate the membrane excitability of MDH neurons, which was related to the activation of NSCC.

• Imaging Science in Dentistry
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• 제45권2호
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• pp.81-87
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• 2015

Purpose: Contrast, sharpness, enhancement, and density can be changed in digital systems. The important question is to what extent the changes in these variables affect the accuracy of caries detection. Materials and Methods: Forty eight extracted human posterior teeth with healthy or proximal caries surfaces were imaged using a photostimulable phosphor (PSP) sensor. All original images were processed using a six-step method: (1) applying "Sharpening 2" and "Noise Reduction" processing options to the original images; (2) applying the "Magnification 1:3" option to the image obtained in the first step; (3) enhancing the original images by using the "Diagonal/"option; (4) reviewing the changes brought about by the third step of image processing and then, applying "Magnification 1:3"; (5) applying "Sharpening UM" to the original images; and (6) analyzing the changes brought about by the fifth step of image processing, and finally, applying "Magnification 1:3." Three observers evaluated the images. The tooth sections were evaluated histologically as the gold standard. The diagnostic accuracy of the observers was compared using a chi-squared test. Results: The accuracy levels irrespective of the image processing method ranged from weak (18.8%) to intermediate (54.2%), but the highest accuracy was achieved at the sixth image processing step. The overall diagnostic accuracy level showed a statistically significant difference (p=0.0001). Conclusion: This study shows that the application of "Sharpening UM" along with the "Magnification 1:3" processing option improved the diagnostic accuracy and the observer agreement more effectively than the other processing procedures.

• Imaging Science in Dentistry
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• 제45권4호
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• pp.221-226
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• 2015

Purpose: This study evaluated the prevalence of distolingual roots in mandibular molars among Koreans, the root canal system associated with distolingual roots, and the concurrent appearance of a distolingual root in the mandibular first molar and a C-shaped canal in the mandibular second molar. Materials and Methods: Cone-beam computed tomographic images of 264 patients were screened and examined. Axial sections of 1056 mandibular molars were evaluated to determine the number of roots. The interorifice distances from the distolingual canal to the distobuccal canal were also estimated. Using an image analysis program, the root canal curvature was calculated. Pearson's chi-square test, the paired t-test, one-way analysis of variance, and post-hoc analysis were performed. Results: Distolingual roots were observed in 26.1% of the subjects. In cases where a distolingual root was observed in the mandibular molar, a significant difference was observed in the root canal curvature between the buccolingual and mesiodistal orientations. The maximum root canal curvature was most commonly observed in the mesiodistal orientation in the coronal portion, but in the apical portion, maximum root canal curvature was most often observed in the buccolingual orientation. Conclusion: The canal curvature of distolingual roots was found to be very complex, with a different direction in each portion. No correlation was found between the presence of a distolingual root in the mandibular first molar and the presence of a C-shaped canal in the mandibular second molar.

• Imaging Science in Dentistry
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• 제41권3호
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• pp.115-121
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• 2011

Purpose : This article is to describe a modified device for intraoral radiography which was developed to obtain reproducible radiographic images for assessment of distal osseous defects of the mandibular second molar (2 Mm) after impacted third molar (3 Mm) surgery. Materials and Methods : A commercial available alignment system for posterior region was modified by adding a reference gauge pin (millimetric) and threading a hollow acrylic cylinder at the ring of the radiographic positioner to attach the X-ray collimator. The design included customized resin acrylic stent for the occlusal surface of the 2Mm in maximum intercuspal position, individualizing the biteblock positioner. Periapical radiographs were taken before and after surgical extraction of 3 Mm, employing the radiographic technique of parallelism described by Kugelberg (1986) with this modified film holder and inserting the gauge pin on the deepest bone probing depth point. Results : This technique permitted to obtain standardized periapical radiographs with a moderate to high resolution, repeatability, and accuracy. There was no difference between the measurements on the pre- and post-operative radiographs. This technique allowed better maintenance of the same geometric position compared with conventional one. The insertion of the gauge pin provided the same reference point and localized the deepest osseous defect on the two-dimensional radiographs. Conclusion : This technique allowed better reproducibility in posterior radiographic records (distal surface of 2 Mm) and more accurate measurements of radiographic bone level by the use of a millimetric pin.

• Clinical and Experimental Reproductive Medicine
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• 제47권4호
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• pp.237-244
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• 2020

Endometrial cancer (EC) in young women tends to be early-stage and low-grade; therefore, such cases have good prognoses. Fertility-sparing treatment with progestin is a potential alternative to definitive treatment (i.e., total hysterectomy, bilateral salpingo-oophorectomy, pelvic washing, and/or lymphadenectomy) for selected patients. However, no evidence-based consensus or guidelines yet exist, and this topic is subject to much debate. Generally, the ideal candidates for fertility-sparing treatment have been suggested to be young women with grade 1 endometrioid adenocarcinoma confined to the endometrium. Magnetic resonance imaging should be performed to rule out myometrial invasion and extrauterine disease before initiating fertility-sparing treatment. Although various fertility-sparing treatment methods exist, including the levonorgestrel-intrauterine system, metformin, gonadotropin-releasing hormone agonists, photodynamic therapy, and hysteroscopic resection, the most common method is high-dose oral progestin (medroxyprogesterone acetate at 500-600 mg daily or megestrol acetate at 160 mg daily). During treatment, re-evaluation of the endometrium with dilation and curettage at 3 months is recommended. Although no consensus exists regarding the ideal duration of maintenance treatment after achieving regression, it is reasonable to consider maintaining the progestin therapy until pregnancy with individualization. According to the literature, the ovarian stimulation drugs used for fertility treatments appear safe. Hysterectomy should be performed after childbearing, and hysterectomy without oophorectomy can also be considered for young women. The available evidence suggests that fertility-sparing treatment is effective and does not appear to worsen the prognosis. If an eligible patient strongly desires fertility despite the risk of recurrence, the clinician should consider fertility-sparing treatment with close follow-up.

• 치위생과학회지
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• 제13권2호
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• pp.191-196
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• 2013

본 연구는 미백치약의 효능을 확인하고 미백치약으로 미백된 치아의 식음음료에 따른 재착색의 정도를 확인하고자 실시되었다. 30개의 치아를 두 그룹으로 나누어 미백치약의 효능을 평가하였고 평가된 치아는 다시 착색음료에 담가 색변화를 관찰하였다. 그 결과, 미백치약은 사용한지 21일부터 일반치약을 사용한 치아와의 색변화에서 유의한 차이를 확인할 수 있었다(p>0.05). 미백된 치아의 재착색에서는 오렌지주스에 담군 치아가 가장 색변화가 크고 분명하였으나 일반치약을 사용한 치아와 유의한 차이를 보이지는 않았다(p>0.05). 커피와 녹차에 담근 치아는 각각 15일, 5일부터 유의한 차이를 보였으며 (p>0.05), 녹차에 담근 치아가 음의 색변화가 더 높은 것으로 나타났다. 따라서, 본 실험에 사용된 대표적인 3개의 식음음료 중 커피와 녹차에서 미백된 치아에서 더 착색이 잘 일어나는 것을 확인하였다.

• Imaging Science in Dentistry
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• 제54권2호
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• pp.129-137
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• 2024

Purpose: Patients with head and neck cancer (HNC) who undergo dental procedures during radiotherapy (RT) face an increased risk of developing osteoradionecrosis (ORN). Accordingly, new tools must be developed to extract critical information regarding the dose delivered to the teeth and mandible. This article proposes a novel approach for visualizing 3-dimensional planned dose distributions on panoramic reconstruction computed tomography (pCT) images. Materials and Methods: Four patients with HNC who underwent volumetric modulated arc therapy were included. One patient experienced ORN and required the extraction of teeth after RT. In the study approach, the dental arch curve (DAC) was defined using an open-source platform. Subsequently, pCT images and dose distributions were generated based on the new coordinate system. All teeth and mandibles were delineated on both the original CT and pCT images. To evaluate the consistency of dose metrics, the Mann-Whitney U test and Student t-test were employed. Results: A total of 61 teeth and 4 mandibles were evaluated. The correlation coefficient between the 2 methods was 0.999, and no statistically significant difference was observed (P>0.05). This method facilitated a straightforward and intuitive understanding of the delivered dose. In 1 patient, ORN corresponded to the region of the root and the gum receiving a high dosage (approximately 70 Gy). Conclusion: The proposed method particularly benefits dentists involved in the management of patients with HNC. It enables the visualization of a 3-dimensional dose distribution in the teeth and mandible on pCT, enhancing the understanding of the dose delivered during RT.

• 한국의학물리학회지:의학물리
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• 제26권1호
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• pp.52-58
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• 2015

본 연구팀이 개발한 신개념 강내형 치과 진단 장치에서 촬영한 X선 치아영상으로부터 치아 우식증을 조기 단계에서 판별하고 치과의사의 정확한 진단을 돕기 위해서 병변진단 보조시스템인 치아 와동 자동 검출 프로그램을 개발하고자 하였다. 치아 와동 자동 검출 시스템을 구성하고 있는 기본 알고리즘은 치아 와동과 정상 치아를 구분 할 수 있는 영상분별 알고리즘과 치아 영상의 고유 특성 정보를 분석하고 이를 병변 검출에 적용할 수 있는 알고리즘으로 나눌 수가 있는데, 본 연구에서는 먼저, DRLSE 방법을 적용하여 병변과 정상치아 사이의 윤곽선 분할 성능을 테스트 하였다. 개발된 알고리즘의 와식 판별 성능을 테스트하기 위해서 다양한 형태의 와식을 포함하는 전치, 견치, 소구치 등의 7개의 치아팬텀을 제작하고 치아 와식 분별을 실시하였다. 총 14 개의 와식 중에 와식의 경계를 부분적으로 식별한 2개를 제외하고는 12개 와식의 경계를 정확하게 구별하여 개발된 자동 치아 병변 알고리즘의 가능성을 입증하였다. 그러나 실제 치아 와식의 형태는 개개인마다 다르고 복잡하기 때문에 무작위로 선택된 실제 치아에 적용하기 위해서는 보강된 알고리즘이 필요하다. 향후에는 치아에 대한 사전정보를 처리하고 적용하는 패턴 인식 혹은 기계학습 알고리즘을 추가하여 보다 효과적이고 정확한 병변 알고리즘으로 개선할 예정이다.