• Journal of Dental Rehabilitation and Applied Science
• /
• v.29 no.2
• /
• pp.163-173
• /
• 2013

When the mandible performs opening movement, the condyle-disk complex conducts sliding movement along the articular eminence. Thus, anatomic configuration of articular eminence is very important to normal movement of TMJ. The purpose of this study was to measure the posterior slope of the articular eminence and evaluate the effect of a pathologic bone change in the condylar head on the stiffness of articular eminence, and compare the differences of the articular eminence slope by gender and age using dental cone-beam CT. As using i-CAT Cone-Beam Computed Tomography, the CT images of 204 TMJs of 102 patients(43 men and 59 women, mean age: 37.7 years) who were diagnosed at Wonkwang University Sanbon Dental Hospital were evaluated. All images were converted into a TMJ analysis mode to observe the continuous sagittal section images and coronal section images of the joints. To observe and assess bone changes in the condyle, three dentists measured the stiffness of the articular eminence on the same images, and when two of the three dentists agreed on their reading, these results were adopted and recorded. The articular eminence slope, considering the condylar anatomic configuration, was measured in three regions, namely, lateral part, central part, and medial part of the condyle. In the cases of a normal condyle(NCBC) and a condyle(CBC) with bone change, the articular eminence slopes were $57.0^{\circ}$(NCBC) and $51.8^{\circ}$(CBC) at the medial part, $57.9^{\circ}$(NCBC) and $52.4^{\circ}$(CBC) at the central part, and $55.1^{\circ}$(NCBC) and $49.5^{\circ}$(CBC) at the lateral part of the condyle. And the articular eminence slope of the condyle with bone change demonstrated less steepness than that of normal condyle (p<0.05). The articular eminence slope showed mediolaterally that it was the steepest at the central, followed by at the medial, and at the lateral (p<0.05). There were no significant differences by the gender and the age (p.0.05).

• Korean Journal of Microbiology
• /
• v.52 no.2
• /
• pp.140-147
• /
• 2016

A process for manufacturing virally-safe porcine bone hydroxyapatite (HA) has been developed to serve as advanced xenograft material for dental applications. Porcine bone pieces were defatted with successive treatments of 30% hydrogen peroxide and 80% ethyl alcohol. The defatted porcine bone pieces were heat-treated in an oxygen atmosphere box furnace at $1,300^{\circ}C$ to remove collagen and organic compounds. The bone pieces were ground with a grinder and then the bone powder was sterilized by gamma irradiation. Morphological characteristics such as SEM (Scanning Electron Microscopy) and TEM (Transmission Electron Microscopy) images of the resulting porcine bone HA (THE Graft$^{(R)}$) were similar to those of a commercial bovine bone HA (Bio-Oss$^{(R)}$). In order to evaluate the efficacy of $1,300^{\circ}C$ heat treatment and gamma irradiation at a dose of 25 kGy for the inactivation of porcine viruses during the manufacture of porcine bone HA, a variety of experimental porcine viruses including transmissible gastroenteritis virus (TGEV), pseudorabies virus (PRV), porcine rotavirus (PRoV), and porcine parvovirus (PPV) were chosen. TGEV, PRV, PRoV, and PPV were completely inactivated to undetectable levels during the $1,300^{\circ}C$ heat treatment. The mean log reduction factors achieved were $${\geq_-}4.65$$ for TGEV, $${\geq_-}5.81$$ for PRV, $${\geq_-}6.28$$ for PRoV, and $${\geq_-}5.21$$ for PPV. Gamma irradiation was also very effective at inactivating the viruses. TGEV, PRV, PRoV, and PPV were completely inactivated to undetectable levels during the gamma irradiation. The mean log reduction factors achieved were $${\geq_-}4.65$$ for TGEV, $${\geq_-}5.87$$ for PRV, $${\geq_-}6.05$$ for PRoV, and $${\geq_-}4.89$$ for PPV. The cumulative log reduction factors achieved using the two different virus inactivation processes were $${\geq_-}9.30$$ for TGEV, $${\geq_-}11.68$$ for PRV, $${\geq_-}12.33$$ for PRoV, and $${\geq_-}10.10$$ for PPV. These results indicate that the manufacturing process for porcine bone HA from porcine-bone material has sufficient virus-reducing capacity to achieve a high margin of virus safety.

• Journal of the Korean Society of Radiology
• /
• v.16 no.6
• /
• pp.673-680
• /
• 2022

In this study, based on PLA, we analyzed the Hounsfield Unit (HU) of materials containing 20% each of aluminum, wood, copper, carbon, and marble, and tried to analyze how they affect the image. A cylindrical phantom of 5×30×30 ㎣ (thickness×diameter×height) was fabricated using a entry-level 3D printer. The kV was changed to 80, 100 and 120, and the mAs was changed to 100 and 200 mAs, and the phantom in the center of the table was cross-scanned under a total of six conditions. A circular ROI was set using image J program and the quantification value of the material part HU and the quantification value of the peripheral part CNR were obtained. The HU average of the material part increased in the order of [PLA - wood 20%], [PLA - marble 20%], [PLA - carbon 20%], [PLA 100%], [PLA - aluminum 20%], [PLA - copper 20%] (p<0.05) a negative correlation was confirmed with the HU by increasing kV. It was confirmed that the CNR value in the peripheral area increased in the order of [PLA - marble 20%], [PLA - copper 20%], [PLA - carbon 20%], [PLA - wood 20%], [PLA - aluminum 20%], and [PLA - 100%] (p<0.05). Human organs with similar HU values for each material are [PLA - copper 20%] compact bone, [PLA - aluminum 20%] cancellous bone, [PLA 100%] coagulated blood, [PLA - carbon 20%] and [PLA - marble 20%] liver, muscle, spleen and [PLA - wood 20%] had similar values to fat. In addition, we confirmed the blur phenomenon that blurs the image around the filament with all materials, and confirmed that [PLA 100%] especially has the most blur around the filament. Therefore, it is considered desirable to reflect the HU value of the target organ and consider cloudiness around the phantom when selecting materials for medical phantom fabrication, and this research can provide basic data.

• Journal of Nutrition and Health
• /
• v.50 no.2
• /
• pp.142-157
• /
• 2017

Purpose: The purpose of this study was to develop a nutrition quotient for adolescents (NQ-A) to assess overall dietary quality and food behavior of Korean adolescents. Methods: Development of the NQ-A was undertaken in three steps: item generation, item reduction, and validation. Candidate items of the NQ-A checklist were selected based on literature reviews, results of the fifth Korea National Health and Nutrition Examination Survey data, dietary guidelines for Korean adolescents, expert in-depth interviews, and national nutrition policies and recommendations. A total of 213 middle and high school students participated in a one-day dietary record survey and responded to 41 items in the food behavior checklist. Pearson's correlation coefficients between the responses to the checklist items along with nutritional status of the adolescents were calculated. Item reduction was performed, and 24 items were selected for the nation-wide survey. A total of 1,547 adolescents from 17 cities completed the checklist questionnaire. Exploratory factor and confirmatory factor analyses were performed to develop a final NQ-A model. Results: Nineteen items were finalized as the checklist items for the NQ-A. Checklist items were composed of five factors (balance, diversity, moderation, environment, and practice). The five-factor structure accounted for 47.2% of the total variance. Standardized path coefficients were used as weights of the items. The NQ-A and five-factor scores were calculated based on the obtained weights of the questionnaire items. Conclusion: Nutrition Quotient for adolescents (NQ-A) would be a useful instrument for evaluating dietary quality and food behavior of Korean adolescents. Further research on NQ-A is needed to reflect changes in adolescent's food behavior and environment.

• Economic and Environmental Geology
• /
• v.35 no.1
• /
• pp.25-41
• /
• 2002

In order to investigate the hydrogeochemical characteristics and contamination of dissolved major ions and heavy metals in the Tancheon River, river water and sediment samples were collected at 18 locations, along a distance of 69 km, between Yongin-si in Kyunggi-do and Samsung-dong in Seoul on October in 2000 and April in 2001. After appropriate sample preparation, waters were analyzed for the dissolved constituents and sediments. The pH values of river waters were in the range of 7.0 to 9.3 and could be plotted in the area of surface environment. The level of $Ca^{2+}$, , CI-, sol-, N0$_{3}$ and HC0$_{3}$ in the Tancheon River were higher than those in world average river water. Most of dissolved constituents in the river waters increased toward downstream from upstream. In particular, high concentrations of Zn2+, Na$_{+}$, CI$^{-}$, SO$_{4}^{2-}$ and N03- were found near densely residential areas and the Sungnam waste water treatment plant. The relative ion enrichment was caused by the inflow of local domestic and industrial sewages. Also, Ca2+ and HC03- concentrations were enriched in the middle of the Tancheon River due to the dissolution of cements. This indicates that the apartment complexes were built on a large scale in the upriver since these ten years and large amounts of construction materials such as cements were flowed into the Tancheon River. Concentrations of heavy metals (Mn, Cd, Cu, Pb, Zn) in sediments from the Tancheon River exceeded the lower limit of tolerence level in bottom sediment established by the Ontario Ministry of the Environment (OME) of Canada. In particular, these metals were highly elevated in sediment (TSM-12) collected from near the Sungnam waste water treatment plant. Heavy metals were higher enriched in sediments collected from dry period rather than wet period.

• Journal of Nutrition and Health
• /
• v.53 no.6
• /
• pp.629-647
• /
• 2020

Purpose: This study was undertaken to develop a nutrition quotient for elementary school children (NQ-C) for evaluating the overall dietary quality and eating behaviors. Methods: The NQ-C was developed by implementing 3 stages: item generation, item reduction, and validation. Candidate food behavior checklist (FBC) items of the NQ-C were derived from systematic literature reviews, expert in-depth interviews, statistical analyses of the fifth Korean National Health and Nutrition Examination Survey data, and national nutrition policies and recommendations. For the pilot survey, 260 elementary school students (128 second graders and 132 fifth graders) completed self-administered questionnaires as well as 24-hour dietary intakes, with the help of their parents and survey team staff, if required. Based on the pilot survey results, expert reviews, and priorities of national nutrition policy and recommendations, checklist items were reduced from 41 to 24. A total of 20 items for NQ-C were finally selected from results generated from 1,144 nationwide samples surveyed. Construct validity of the NQ-C was assessed using the confirmatory factor analysis, LInear Structural RELations. Results: Analyses of the exploratory factors of NQ-C identified that 5 dimensions of diet (balance, diversity, moderation, practice and environment) accounted for 46.2% of the total variance. Standardized path coefficients were used as weights of the items. The NQ-C and 5-factor scores of the subjects were calculated using the obtained weights of the FBC items. Conclusion: Our data indicates that NQ-C is a useful and suitable instrument for assessing nutrition adequacy, dietary quality, and eating behaviors of Korean elementary school children.

• Journal of the Daesoon Academy of Sciences
• /
• v.41
• /
• pp.133-178
• /
• 2022

This study investigates if four propitious sites (四明堂, sa myeongdang) identified in Daesoon Jinrihoe's The Canonical Scripture correspond with the orthodox descriptions of dragon, energy hub, sand, and water (龍穴砂水, yong hyeol sa su) which are held by Fengshui as conditions necessary for that specific designation. In this study, these conditions, based on the shape of the site-formations, were observed via through on-site surveys and the application of the theories presented by traditional books on Fengshui. First, the dragon veins (龍脈, yongmaek) of the energy hub of the Five Immortals Playing Baduk (五仙圍碁穴 oseonwigi- hyeol) on Mount Hoemun in Sunchang consists of solid soil, is like a spiderweb, rises and lays prone, winds in every direction, and looks almost disconnected while actually remaining connected. Second, the Fengshui characteristics of the energy hub of Worship Held by Buddhist Monks from Abroad (胡僧禮佛穴, hoseungyebul- hyeol) on Mount Seungdal in Muan is that the branching feet (枝脚 jigak) support the mountain range by forming a valley to the left and right of the dragon veins that stretch from the peak of Mount Seungdal. Also, the direction-changing helm (橈棹 yodo) supports the mountain range solidly can be said to be well-developed. It is likewise noted that there is an excellent change in dragon veins in that exhibit curvature that spans being high, low, rising, and lying. This makes it appear as though the dragon is wriggling back and forth. Third, the state of the energy hub of Celestial Maidens Weaving Silk (仙女織錦穴, seonnyojikgeum-hyeol) on Sonryong Ridge in Jangseong County demonstrates overall harmony between mountain and water as it is near Mount Ju and Mount An and has a solid water outlet to which it is tightly fastened such that its energy does not leak out. Meanwhile, the positioning of its blue dragon of the east, red phoenix of the south, white tiger of the west, and black tortoise of the north is so intimate that its long flow can be said to be spinning. The Songryong Ridge area where energy hub was formed between soil and bedrock is the right land for a great favored location as it corresponds with Fengshui logic in an exemplary manner. Fourth, the Fengshui characteristics of the energy hub of Subjects Receiving the Imperial Command (群臣奉詔穴, gunshinbongjo-hyeol) at Baerye-jeon Field in Taein can be described as embracing the village snuggly as it centers around Mount Wangja, and its blue dragon and white tiger respond to each other. Additionally, a clear distinction between host and guest is noticeable in the positions of Mount Ju and Mount An. The flowing body of water in front of the village wraps around that village as a Horizontal Water Formation (橫水局, hoengsuguk), and vigorous vapor from the earth draws breath as the yin-yang energy of the landscape courses through the earth. As dragon veins, the range of the mountain, are like the blood vessels within the human body and the dragon is compared to the limbs, the energy hub of Subjects Receiving the Imperial Command at Baerye-jeon Field in Taein can be identified as a favored location that was formed directly by the sky and earth.

• The korean journal of orthodontics
• /
• v.36 no.5
• /
• pp.339-348
• /
• 2006

Objective: With development of the skeletal anchorage system, orthodontic mini-implant (OMI) assisted on masse sliding retraction has become part of general orthodontic treatment. But compared to the emphasis on successful anchorage preparation, the control of anterior teeth axis has not been emphasized enough. Methods: A 3-D finite element Base model of maxillary dental arch and a Lingual tipping model with lingually inclined anterior teeth were constructed. To evaluate factors influencing the axis of anterior teeth when OMI was used as anchorage, models were simulated with 2 mm or 5 mm retraction hooks and/or by the addition of 4 mm of compensating curve (CC) on the main archwire. The stress distribution on the roots and a 25000 times enlarged axis graph were evaluated. Results: Intrusive component of retraction force directed postero-superiorly from the 2 mm height hook did not reduce the lingual tipping of anterior teeth. When hook height was increased to 5 mm, lateral incisor showed crown-labial and root-lingual torque and uncontrolled tipping of the canine was increased.4 mm of CC added to the main archwire also induced crown-labial and root-lingual torque of the lateral incisor but uncontrolled tipping of the canine was decreased. Lingual tipping model showed very similar results compared with the Base model. Conclusion: The results of this study showed that height of the hook and compensating curve on the main archwire can influence the axis of anterior teeth. These data can be used as guidelines for clinical application.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.43 no.1
• /
• pp.93-108
• /
• 2016

One of the fields to which the 3D printing technology can be applied is the field of medicine. Recently, the application of 3D printing technology to the bio-medical field has been gradually increasing with the commercializing of the bio-compatible or bio-degradable materials. The technology is currently contributing to the biomedical field by reducing times required for operations or minimizing adverse effects through preoperative identification of post-surgical consequences or model surgery with artificial bones and organs. This technology also enables the production of customized biomedical auxiliary products like hearing aids or artificial legs etc. For the field of dentistry, the 3D printing technology is also expected to elevate the level of dental treatment by making the customized orthodontic models, crown, bridge, inlay, and surgical guides for implant and surgery. However, issues remaining unidentified or incomplete in printing materials, modeling technology, software technology associated with CAD, verification of bio-stability and bio-effectiveness of materials or in compatibility and standardization of the technology are yet to be solved or be clarified for the full-scale application of the 3D printing technology, thus, it seems such issues should be resolved through further studies.

• The Journal of Korean Academy of Prosthodontics
• /
• v.8 no.1
• /
• pp.48-55
• /
• 1968

1958년(年) Fullmer와 $Lillie^9$에 의(依)하여 최초(最初)로 보고(報告)된 Oxytalan 섬유(纖維)는 산(酸)에 내성(耐性)이 강(强)한 섬유(纖維)로 치근막(齒根膜)에 많이 출현(出現)하고 기계적(機械的) 자극(刺戟)에 의(依)하여 배열(配列), 주행(走行) 및 수적(數的)인 변화(變化)를 가져온다. 저자(著者)는 교정력(矯正力)을 이용(利用)하여 치아(齒牙)를 이동(移動) 시킨후(後) 치근막내(齒根膜內) Oxytalan섬유(纖維)의 수(數), 주행(走行) 및 형태(形態)의 변화(變化)를 실험적(實驗的)으로 관찰(觀察)한바 있어 이를 보고(報告)하는 바이다. 본연구(本硏究)에 사용(使用)된 실험동물(實驗動物)로는 체중(體重) 60gram내외(內外)의 자성백서(雌性白鼠) 15마리를 택(澤)하였다. 각동물(各動物)은 Ether마취후(麻醉後) 교정용(矯正用) 고무줄편(片)을 상악우측(上顎右側) 제1구치(第一臼齒)와 제2구치(第二臼齒) 사이에 삽입(揷入)하여 24, 48, 72시간(時間) 간격(間隔)으로 관찰(觀察)하였다. 동물(動物)을 도살후(屠殺後) 상악골(上顎骨)을 적출(摘出)하여 10%중성(中性) 호루마린에 고정후(固定後) 3%의산(蟻酸)으로 탈회(脫灰)하였다. 파라핀 포매후(包埋後) 근원심적(近遠心的)으로 $4{\sim}6{\mu}$의 절편(切片)을 만들어 Hematoxylin-eosin 및 Aldehyde fuchsin염색(染色)을 시행(施行)하여 경험(鏡險)한 결과(結果)는 하기(下記)와 같다. 1. 치아이동후(齒牙移動後) 교원성섬유(膠原性纖維) 및 Oxytalan섬유(纖維)들의 배열(配列)에 있어 뚜렷한 차이(差異)를 보였다. 2. 치아이동후(齒牙移動後) 사주섬유(斜走纖維)는 염박측(壓迫側)에서는 치아장축(齒牙長軸)에 수직(垂直)되게, 견인측(牽引側)에서는 평행(平行)되게 주행(走行)하고 있었다. 3. 48시간군(時間群)에서 세포증식(細胞增殖)이 심(甚)하였다. 4. Oxytalan섬유(纖維)는 치아(齒牙)들에 교정력(矯正力)을 가(加)한후(後) 견인(牽引) 염박(壓迫) 양측(兩側) 공(共)히 수(數)가 증가(增加)하였다. 5. 염박측(壓迫側)에서 Oxytalan섬유(纖維)는 속(束)을 형성(形成)하며 치아장축(齒牙長軸)에 평행(平行)되게 주행(走行)하였다. 6.견인측(牽引側)에서는 하나 또는 두세개의 섬유(纖維)들이 산발적(散發的)으로 치아장축(齒牙長軸)에 평행(平行)되게 하였다. 7. Oxytalan섬유(纖維)의 수(數)는 염박측(壓迫側)에서 보다 견인측(牽引側)에서 더 변화(變化)가 많았다.