• 대한치과교정학회지
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• 제51권1호
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• pp.23-31
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• 2021

Objective: To evaluate the mandibular buccal shelf (MBS) in terms of the angulation and bone depth and thickness according to sex, age, and sagittal and vertical skeletal patterns in a Colombian population using cone-beam computed tomography (CBCT). Accordingly, the optimal site for miniscrew insertion in this area was determined. Methods: This descriptive, retrospective study included 64 hemi-arches of 34 patients. On CBCT images, the angulation, buccal bone depth (4 and 6 mm from the cementoenamel junction [CEJ] of MBS), and buccal bone thickness (6 and 11 mm from the CEJ of MBS) were measured at the mesial and distal roots of the mandibular first and second molars. Results: There were no statistically significant differences in the angulation, depth, and thickness of MBS between male and female patients. The values for the bone around the distal root of the mandibular second molar were significantly greater than the other values. The osseous characteristics were significantly better in participants aged 16-24 years. Class III patients exhibited the best osseous characteristics, with the bone depth at 6 mm being significantly different from that in Class I and Class II patients. Although values tended to be greater in patients with low angles, the difference was not statistically significant. Conclusions: MBS provides an optimal bone surface for miniscrew insertion, with better osseous characteristics at the distal root of the mandibular second molar, 4 mm from CEJ. Adolescent patients, Class III patients, and patients with a low angle exhibit the most favorable osseous characteristics in the MBS area.

• 동의생리병리학회지
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• 제26권6호
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• pp.947-952
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• 2012

This Study was conducted to investigate Muscle Test of Point Selection through CRA(Contact Reflex Analysis) Muscel Diagnosis. So this study used to compare and analyze the effects of Muscel(Deltoid Muscel of Posterior) RMS(Root Mean Squared) and MEF(Median Edge Frequency) Among Groups that do not respond to questionnaire, Tonguibogam Naegyeongpyeon Small Intestine Group, Small Intestine MeridianPathway Primary Symptom and Secondary Symptom Group and Kwanwon(CV4) meridian Principal action Group. The questionnaire is composed of 23 items. The questionnaire was intended to elicit information on assorting into 4 groups. After Survey, Subject had to Muscle test subjects. Muscle experimental methods are as follows: Holding the shoulder without contacting Kwanwon. Holding the shoulder contacting Kwanwon. The first iteration. Group 1,2,3 were increased sEMG RMS compared with First experiment and Second experiment. Group 4(Including Uterus and Intestinal Flora Problem) were decreased sEMG RMS compared with First experiment and Second experiment. This test means that it is similar to diagnosis CRA and Small intestine channel of hand taiyang muscle, not Small Intestine MeridianPathway. It is suggested that subjects with a Small Intestine problem(Uterus and Intestinal Flora Problem) shows the results of decreasing posterior Deltoid Muscular strength. It means that CRA muscle diagnosis is associated with Alarm points diagnosis. But it doesn't consider influence of fat on the surface EMG.

• Imaging Science in Dentistry
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• 제38권3호
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• pp.163-167
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• 2008

Purpose : The purpose of this study is to evaluate the position of the mandibular canal in relation to the mandibular third molar by cone beam CT in cases showing a close relationship between the third molar and the mandibular canal on the panoramic radiograph. Materials and Methods : The panoramic images and cone beam CT scans of 87 impacted mandibular third molars in 60 patients were evaluated to assess the tooth relationship to the mandibular canal. The clearness of the canal wall and the vertical depth of the lower third molar were evaluated on panoramic radiographs. The lower third molars were assessed using cone beam CT to determine the proximity and position of the canal relative to the roots. Results : In the 66 cases where the canal wall was unclear on the panoramic radiographs, 58 (87.9%) of the third molars had contact between the canal and root; 34 (51.5%) canals were showed an inferior position and 22 (33.3%) showed a linguoinferior position on cone beam CT. Conclusion : Interruption of the canal wall on panoramic radiographs was highly predictive of contact between the mandibular canal and the third molar. Cross sectional CT may be indicated for localization of the mandibular canal in such cases.

• 한국재료학회지
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• 제23권3호
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• pp.194-198
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• 2013

In this paper, we studied a p-type reflector based on indium tin oxide (ITO) for vertical-type ultraviolet light-emitting diodes (UV LEDs). We investigated the reflectance properties with different deposition methods. An ITO layer with a thickness of 50 nm was deposited by two different methods, sputtering and e-beam evaporation. From the measurement of the optical reflection, we obtained 70% reflectance at a wavelength of 382 nm by means of sputtering, while only 30% reflectance resulted when using the e-beam evaporation method. Also, the light output power of a $1mm{\times}1mm$ vertical chip created with the sputtering method recorded a twofold increase over a chip created with e-beam evaporation method. From the measurement of the root mean square (RMS), we obtained a RMS value 1.3 nm for the ITO layer using the sputtering method, while this value was 5.6 nm for the ITO layer when using the e-beam evaporation method. These decreases in the reflectance and light output power when using the e-beam evaporation method are thought to stem from the rough surface morphology of the ITO layer, which leads to diffused reflection and the absorption of light. However, the turn-on voltage and operation voltage of the two samples showed identical results of 2.42 V and 3.5 V, respectively. Given these results, we conclude that the two ITO layers created by different deposition methods showed no differences in the electric properties of the ohmic contact and series resistance.

• Imaging Science in Dentistry
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• 제42권3호
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• pp.121-127
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• 2012

Purpose: This study evaluated the association between cone beam computed tomography (CBCT) and panoramic radiographs in the assessment of a superimposed relationship between the mandibular canal and impacted third molars. Materials and Methods: The study samples consisted of 175 impacted third molars from 131 patients who showed a superimposed relationship between the mandibular canal and third molars on panoramic radiographs and were referred for the examination of the mandibular canal with CBCT. Panoramic images were evaluated for the darkening of the root and the interruption of the mandibular canal wall. CBCT images were used to assess the buccolingual position of the mandibular canal relative to the third molar, the proximity of the roots to the canal, and lingual cortical bone loss. The association of the panoramic and CBCT findings was examined using a Chi-square test and Fisher's exact test. Results: Panoramic radiographic signs were statistically associated with CBCT findings (P<0.01). In cases of darkening roots, lingual cortical bone loss or buccally positioned canals were more frequent. In cases in which the mandibular canal wall was interrupted on panoramic radiographs, contact or lingually positioned canals were more frequent. Conclusion: The results of this study suggest that contact between the mandibular third molar and canal and a lingually positioned canal could be more frequently observed in cases of the interruption of the white line of the mandibular canal and that there could be more lingual cortical loss in cases of darkening roots.

• 대한소아치과학회지
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• 제32권3호
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• pp.537-542
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• 2005

구강악안면 영역의 외상은 치아파절, 탈구, 골절, 연조직 손상을 일으킬 수 있으며, 뇌진탕의 원인이 되기도 한다. 미국과 일본에서는 contact sports 일부에서 마우스가드의 장착이 의무화되어 있으나, 현재 한국에서는 운동 시 마우스가드의 장착을 거의 볼 수 없는 실정이다. 마우스가드는 크게 ready-made type과 custom-made type으로 나눌 수 있다. Ready made type의 마우스가드에는 형태가 일정하고 조정이 곤란한 stock mouthguard와 다소 조정이 가능한 mouth formed mouthguard가 있다. Custommade type의 마우스가드는 적합성이 뛰어나며 정확한 교합, 하악위를 재현할 수 있다는 장점이 있다. 마우스가드는 입술과 구강연조직을 치아로부터 보호하고, 치아에 가해지는 충격을 분산시켜 파절이나 탈구가능성을 줄여준다. 또한, 악골의 골절과 변위를 방지하고 충격을 흡수한다. 성장기 아동의 경우 치아손상의 30% 정도가 스포츠나 레포츠에 의한 것이라는 보고가 있으며, 이 경우 치아나 잇몸은 물론 성장 중인 치조골에 악영향을 주게 된다. 이 때 외상처치는 어려우며, 그 예후 또한 불명확하다. 따라서 성장기 아동의 마우스가드 장착은 외상 예방차원에서 중요하다. 이에 저자는 단국대학교 치과병원에 내원한 환아에게 ERKODENT$^{(R)}$사의 ERKOFORM-RVE를 이용한 흡입성형 마우스가드(vacuum type mouthguard)를 적용한 임상경험을 보고하는 바이다.

• 접착 및 계면
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• 제13권1호
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• pp.24-30
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• 2012

폴리아릴레이트(polyarylate, PAR) 섬유의 산 처리와 자외선 조사 처리에 의한 섬유표면의 미세구조 변화를 SEM과 AFM을 통하여 살펴보고 RMS roughness로 분석하였으며, 접촉각 측정을 하였다. 또한, PAR 섬유의 표면개질이 폴리에틸렌 나프탈레이트(polyethylene naphthalate, PEN) 수지와의 계면접착력에 어떠한 영향을 미치는지를 섬유 풀-아웃 시험(Fiber Pull-out)을 통해 분석하였다. 산처리 농도와 자외선 조사 처리 시간이 증가함에 따라 PAR 섬유의 표면에 에칭이나 크랙이 발생하면서 표면의 거칠기가 증가하는 양상을 보였으며, 물에 대한 접촉각은 감소하는 결과를 보였다. PEN 수지와의 계면접착력을 분석한 결과, 산 처리 농도의 증가와 자외선 조사처리 시간이 경과에 따라 증가하였고 특히, 산 처리 농도 pH 3, 자외선 조사 처리시간이 24 h일 때 최대 계면접착력을 보였다. 이는 섬유표면조도의 증가에 따른 섬유 표면적의 증가로, 계면에서 상호작용할 수 있는 면적이 증가하기 때문이라고 볼 수 있다.

• 대한한의진단학회지
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• 제16권3호
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• pp.41-48
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• 2012

Objectives: The aims of this study are to design a optimized mechanical structure of digital tongue imaging system (DTIS) equipped with LEDs in aspects of object distance and camera angle of coverage. Methods and Results: We tried to find optimized object distance while recording a rectangular object of common tongue size. In case object distance is 22 cm or less, edge of the rectangle was not taken beyond the shooting range. In contrast, if object distance is 40 cm or more, the rectangle image was too small. Therefore when considering the variation of subjects, we selected distance of 35-40 cm as appropriate object distance for the DTIS. We also tried to find optimized angle between camera view axis and horizontal line. We photographed from the side of the face of 7 adults with exposed tongue. We drew an exposed tongue lines to connect the tongue tip points and the tongue root points by using the photos acquired from the side faces. And then we calculated the tongue exposure angles between the vertical line and the exposed tongue lines. Mean tongue exposure angle was $28.3^{\circ}$ when tongue was lightly exposed and $13.3^{\circ}$ when maximally. So we determined $73^{\circ}$ as appropriate slope angle of part in contact with face of the DTIS and by considering that the standard variation was great, we designed control gears to adjust the slope of the camera view axis and to regulate the object distance. Conclusions: We designed a optimized mechanical structure in object distance and slope angle of part in contact with face of the DTIS.

• The Journal of Advanced Prosthodontics
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• 제13권6호
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• pp.351-360
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• 2021

PURPOSE. The aim of this study was to evaluate the efficiency of occlusal and interproximal adjustments of single implant crowns (SIC), comparing a digital cast-free approach (CF) and a protocol using 3D printed casts (PC). MATERIALS AND METHODS. A titanium implant was inserted at position of lower right first molar in a typodont. The implant position was scanned using an intraoral scanner and SICs were fabricated accordingly. Ten crowns (CF; n = 10) were subject to a digital cast-free workflow without any labside occlusal and interproximal modifications. Ten other identical crowns (PC) were adjusted to 3D printed casts before delivery. All crowns were then adapted to the testing model, simulating chair-side adjustments during clinical placement. Adjustment time, quantity of adjustments, and contact relationship were assessed. Data were analyzed using SPSS software (P < .05). RESULTS. Median and interquartile range (IQR) of clinical adjustment time was 02:44 (IQR 00:45) minutes in group CF and 01:46 (IQR 00:21) minutes in group PC. Laboratory and clinical adjustment time in group PC was 04:25 (IQR 00:59) minutes in total. Mean and standard deviation (±SD) of root mean squared error (RMSE) of quantity of clinical adjustments was 45 ± 7 ㎛ in group CF and 34 ± 6 ㎛ in group PC. RMSE of total adjustments was 61 ± 11 ㎛ in group PC. Quality of occlusal contacts was better in group CF. CONCLUSION. Time effort for clinical adjustments was higher in the cast-free protocol, whereas quantity of modifications was lower, and the occlusal contact relationship was found more favourable.

• 한국멀티미디어학회논문지
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• 제24권11호
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• pp.1481-1491
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• 2021

Since most biosignals rely on contact-based measurement, there is still a problem in that it is hard to provide convenience to users by applying them to daily life. In this paper, we present a mobile application for estimating heart rate based on a deep learning model. The proposed application measures heart rate by capturing real-time face images in a non-contact manner. We trained a three-dimensional convolutional neural network to predict photoplethysmography (PPG) from face images. The face images used for training were taken in various movements and situations. To evaluate the performance of the proposed system, we used a pulse oximeter to measure a ground truth PPG. As a result, the deviation of the calculated root means square error between the heart rate from remote PPG measured by the proposed system and the heart rate from the ground truth was about 1.14, showing no significant difference. Our findings suggest that heart rate measurement by mobile applications is accurate enough to help manage health during daily life.