치아 이상의 발생 빈도와 양상에 관한 연구

이제호,손홍규,전승준,최형준 大韓小兒齒科學會 1996 大韓小兒齒科學會誌 Vol.23 No.2

An object definition of the anomaly is not avaliable and most investigators define the term differently or fail to describe their criterion.Because dental anomaly may lead to many complications,early detection and diagnosis of dental anomalies are essential steps in the evaluation of the child patient and in treatment planning.These procedures require detailed medical and dental histories,through clinical examination and the use of radiographs.So,this study was designed to find out the prevalece of dental anomalies.The clinical and roentgenographic examination was undertaken for 8,054 children at age from 0 to 15 years and statistical analysis was done.The results were as follows: 1.Among the examined subjects 2,134 subjects(26.5%) showed dental anomalies.The prevalance of individure dental anomalies were as as follows:Supernumerary teeth 15.6% congenitally missing teeth 6.6%,fusion 2.2%,odontoma 0.35%,microdontia 1.2%,macrodotia 0.05%,gemination 0.22%,talon cusp 0.36%,dens evaginatus 0.24%,dens invaginatus 0.15%,dilaceration 0.27%,taurodontism 0.09%,abnormal tooth position 1.7%,natal $ neonatal teeth 0.92%,amelogenesis imperfecta 0.01%. 2.Significant correlations between the groups with individual dental anomalies were as follows:between groupⅠand other groups,there was nagative correlation,especially groupⅠ and groupⅡ.And the correlation coefficient between male and female showed differences. 3.For the supernumerary teeth group,the prevalence of male was higher than female(p<0.001).While for the congenitally missing teeth,macrodontia,microdontia,abnormal tooth position group,the prevalence of female was greater than male(p<0.001). 4.For the congenitally missing teeth group,the mandibular primary lateral incisor showed the highet incidence in primary dentition,while mandibular lateral incisor in permanent dentition.In the mandible(72.5%),this site showed higher prevelence than in maxilla.In this case with deciduous congenitally missing teeth,the prevelence of successive permanent congenitally missing teeth was about 33.9%,the incidence was highet in mandibular lateral incisors. 5.Most supernumerary teeth existed on middle area and showed inverted position and unerupted state.In addition,supernumerary teeth showed higher incidence on maxilla(99.3%). 6.In the case with deciduous fused teeth,the prevelence of successive permanent congenitally missing teeth was 39.9%,while that of successive permanent fused teeth was 2.7%.And the highet rate of the prevalence(40.3%) appeared in fusion of mandibular deciduous lateral incisor and canine. 7.In the case of odontoma,the prevelence was higher in maxilla(78.6%) and anterior region(82.7%) the mandible and posterior region.

계승영구치가 선천적 결손된 유치의 치근 흡수

이정은,이제호,최형준,김성오,송제선,손흥규,최병재 대한소아치과학회 2009 大韓小兒齒科學會誌 Vol.36 No.4

유치의 정상적인 치근 흡수는 계승 영구치의 맹출 압력으로 단핵구 세포가 방출되어 파골세포로의 분화가 촉진되어 일어나며, 계승 영구치의 맹출 경로를 따라 유치의 치근이 흡수되어서 유치가 탈락하게 된다. 계승 영구치가 선천적으로 결손되었을 때에도 유치의 치근은 흡수될 수 있는데, 유치의 비정상적 치근흡수는 외상이나 염증, 교합압의 증가, 지지조직의 약화 등으로 발생할 수 있다. 치아의 선천적 결손은 인간에서 가장 흔한 발육이상이며, 영구치가 결손되었을 때 유치는 만기 잔존할 수 있다. 영구치의 선천적 결손은 전신질환이 있는 경우뿐만 아니라 국소적 원인이나 인류 진화에 따른 영향 등에 의해서도 발생한다. 이 증례들은 계승 영구치가 선천적으로 결손된 어린이에서 유치의 치근이 비정상적으로 흡수된 경우로 계승 영구치가 결손 된 유전치와 유견치, 유구치의 치근이 1/2 ~ 3/4정도까지 흡수 되었으며 흡수 부위는 불규칙적인 형태를 보였다. 원인으로는 흡수에 감수성이 높은 유치의 치주인대, 그리고 성장에 따라 증가되는 저작근육과 저작력, 혼합치열기에 유발되는 비정상적 교합 등을 생각할 수 있다. 계승 영구치가 결손된 유치가 비정상적인 치근 흡수를 보이는 경우에 유치는 유지될 수도 있지만, 여러 요인에 의하여 탈락될 경우에는 공간을 유지 할 것인지 판단해야 하며, 향후 보철치료나 교정치료를 요하므로 장기적인 치료계획을 수립해야 한다. Root resorption of primary teeth usually occurs as the succeeding permanent teeth erupt, which induces differentiation of the hemopoietic cells into osteoclasts. Their root resorption pattern reflects the eruption path of the succeeding permanent teeth, and eventually the primary teeth shed as their succeeding permanent teeth erupt. Even when a permanent tooth germ is congenitally missing, root resorption of the corresponding primary tooth may still occur due to various factors, such as inflammation, traumatic occlusal force, and weakness of periodontium etc. Such congenital missing of permanent teeth is a commonly observed phenomenon in human be ing, and it often accompanies delayed retention of primary teeth. The etiologic factors for congenital missing in elude not only systemic diseases, but also local factors and human evolution process. In the radiographs of the cases in this report, the primary teeth without succeeding permanent teeth show pathologic root resorption. Root resorption progressed about 1/2~3/4 of the roots, and the surfaces of the resorption area were irregular. Considering high susceptibility of the periodontal ligament of primary teeth to root resorption, pathologic root resorption of primary teeth with delayed retention can be explained by the increased masticatory muscle force and abnormal occlusion developed during the mixed dentition. When the primary teeth without succeeding permanent teeth are lost, decision for space maintenance is required and long-term treatment plan for further prosthetic or orthodontic treatment should be establsihed.

유구치의 편측치아절제술을 이용한 공간유지장치

이제호,김성호,손홍규,김준현 大韓小兒齒科學會 1997 大韓小兒齒科學會誌 Vol.24 No.4

Patient with alveolar abscess due to dental caries with severe alveolar bone loss, severe tooth mobility, root resorption need extraction of tooth because it is impossible to carry out pulp treatment and restoration by using conventional method. Early loss of primary molar might cause masticatory interference, extrusion of opposing tooth, problem in maintaining space and interference on eruption of permanent tooth. Especially, early loss of primary second molar before the eruption of permanent first molar might cause space closure by mesially erupted permanent first molar and impaction of second premolar. In such a case, distal shoe space maintainer and removable space regaining appliance was the first choice of treatment. But, distal shoe space maintainer need precise adaptation and might cause chronic inflammation if the oral hygiene is poor. In a case using removable space regaining appliance, patient's cooperation is most important. If the distal root of primary second molar is comparably sound and alveolar abscess with alveolar bone loss is localized at mesial root, hemisection should be carried out for precise guide to eruption of the permanent first molar, restoration of masticatory fuction and solution to the discomfort of the patient.

2차원 저속절삭에 있어서 버어의 생성에 관한 연구

전태옥,박흥식,이광영,예규현,박윤식 동아대학교 공과대학부설 생산기술연구소 1997 生産技術硏究所硏究論文集 Vol.2 No.2

Recently the development of CNC machine tools seems to bring about progressional high speed, precision, and automation in cutting processing, but is unlikely to avoid the generation of burr arising from plastic deformation, which may result in deterioration of improvement in the precision and productivity of products. This study conducted a comparative analysis of the sizes of burrs via two-dimensional low speed cutting experiments under varied different cutting conditions by taking as its materials of cutting A6061, A2014, STS304 and SM40C commonly used for precision machine paets, motor cars, aircrafts, and so on. When the depths of burrs increase, the size of the burrs are inclined to increase linearly at their final stage rather than the lateral sizes of the burrs. When cutting becomes fast in speed, the lateral sizes of burrs appear consistent, but from a relative perspective the sizes of the final burrs tend to be remarkably increased. An increase in the angle of inclination of α is seen as effective in reducing the thickness of burrs, and burrs were more decreased in size on coating tools rather than in uncoating tools.

수종 치과재료의 제I급 와동에서의 변연 누출에 관한 실험적 연구

이선희,손흥규,최형준 大韓小兒齒科學會 1996 大韓小兒齒科學會誌 Vol.23 No.1

Microleakage is a problem of all filling materials of losted teeth structure and is clinically undetectable. Because marginal leakage may be responsible for pulp irritation, pulp inflammation, necrosis and recurrent caries, it is essential to prevent and control it. For the evaluations of microleakage of various class I filling materials, 175 extracted teeth were filled with amalgam, light curing composite resin, glass inomer cement, IRM and Fermit-N. After thermocycling, speciemens were placed in 1% methylene blue dye solution for 24 hours in an incubator set 37℃. The teeth were sectioned at filling body center and margin and degree of dye penetration was observed with a stereomicroscope. The following results were obtained. 1. Light cured composite resin has the excellent results and microleakage is increased in the order of amalgam, IRM, Fermit-N, glass ionomer cement.(SAS-6.0 system) and there was a statistically significancy in marginal leakage for each filling materials.(Kruskal-Wallis analysis, P<0.05) 2. Microleakage of the center and margin was statistically insignificant (Mann-Whitney analysis P<0.05) 3. There was less microleakage for amalgam than light cured composite resin but was statistically insignificant (Mann-Whitney analysis, P<0.05) and also showed less marginal leakage for Fermit-N compared to glass ionomer cement but also was statistically insignificant. (Mann-Whitney analysis, P<0.05).

BGA 솔더 볼 로딩장치의 최적설계

이준환,이종원,구홍모 중앙대학교 생산공학연구소 1999 생산공학연구소 논문집 Vol.8 No.2

최근의 정보화 장비와 멀티미디어의 소형화 추세는 생산 설비중 반도체 패키지 기술레 힘입은 바 크다. BGA(Ball Grid Array types of package)와 CPS(Chip Scale Packages)는 QFP(Quad Flat Packages)를 대체하는 기술로 인정되고 있다. 볼을 탑재하는 장치는 기존에 진공 - 흡입장치가 많이 사용되어 왔다. 시소 타입 로더에서는 플래이트의 각도와 카트리지의 속도가 중요한 요소로 간주된다. 본 연구에서는 이에 대한 최적 속도와 각도를 제안하였다. With the trends of the recent micro-miniaturization of mutimedia and information equipment, electronic components packaging technology is playing a key role in production technology. BGA(Ball Grid Array thpes of package) and CSP(Chip Scale Packages) are replacing QFT(Quad Flat Packages). Vacuum-suction type loader is a popular loading device. For the seesaw type loader, the velocity fo cartridge and the angle of plate are very important elements. In this study, the optimal values of the velocity and the angle are proposed for the seesaw type loader.

하악 중절치에 발생한 치내치

이정진,최병재,이제호,최형준,손흥규,김성오 大韓小兒齒科學會 2008 大韓小兒齒科學會誌 Vol.35 No.2

치내치(dens invaginatus)는 형태분화기에 비정상적인 치아발생이 원인으로 경조직이 석회화되기 전에 법랑질 상피가 함입되어 생기는 드문 치아 기형이다. 치내치의 발생 빈도는 0.04-10%이고 대부분이 상악에서 발생하며 특히 상악 측절치에서의 빈도가 높고 하악에서는 드물게 발생한다고 보고되었다. 치내치는 우상치나 왜소치,쌍생치,과잉치,상아질 형성부전증과 같은 형태 이상과 연관되어서 나타나는 경우도 있다. 치내치는 함입된 정도에 따라 3가지로 분류할 수 있고 다양한 해부학적 변이를 보이며,이러한 기형은 미생물의 침입을 용이하게 하므로 치아우식증과 치수감염 및 괴사의 위험성을 높인다. 치수조직에 문제가 생긴 경우 근관의 복잡한 해부학적 형태 때문에 근관치료가 매우 어려우므로 조기에 진단하여 치료하는 것이 중요하다. 본 증례들은 하악 중절치에 드물게 발생하는 치내치를 가진 환아에 대한 것으로 하악 중절치에서의 치내치 유병율과 치료에 대한 고찰을 하였기에 이를 보고하는 바이다. Dens invaginatus is a rare malformation resulting from invagination of the enamel before calcification has occurred. It is mostly found in permanent maxillary lateral incisors and mandibular teeth are rarely affected by this anomaly. The malformation is estimated to affect between 0.04 % and 10 % of people and has been associated with other abnormalities such as taurodontism, microdontia, gemination and dentinogenesis imperfects. Dens invaginatus is classified in three types with respect to the depth of invaginatus and has a broad spectrum of morphologic variations. Invagination frequently allows the entry of irritants and microorganism, which usually lead to caries, pulp infection and pulp necrosis. Root canal treatment on such invaginatus tooth may present severe problems because of its complex anatomy of the tooth. Therefore, the early diagnosis of such malformation is crucial and preventive approach is strongly recommended.

초음파 진동판의 표면조도에 따른 분무특성에 관한 연구

이준백,전인곤,전흥신 경희대학교 레이저공학연구소 2000 레이저공학 Vol.11 No.-

The purpose of this study is to compare the SMD(Sauter mean diameter) according to surface roughness of vibrant plates. Liquid film thickness is measured for explanation how to concern ultrasonic atomization. Ultrasonic waves is used for vibration. Immersion liquid method is used for the measure of SMD and liquid film thickness is measured using of point needle method. Distilled water and gasoline fuel are used to liquids. Supplied liquid flow rates are 18∼296cc/min. Centerline average roughness of vibrant plates are 0.5, 2.0, 4.7, 9.5㎛ and diameter of vibrand plate is 60mm. The Vibrant plate with 70, 80mm diameter are used for verify practical limit of horn diameter. In result, good atomization of liquid is obtained in widen flow rates. The mean droplet size is increased in orders of 4.7, 2.0, 9.5, 0.5㎛ surface roughness. Distilled water has a big mean droplet size than gasoline fuel below 78cc/min flow rate but above 78cc/min flow rate, distilled water has a small mean droplet size than gasoline fuel. According to 0∼20.4W ultrsonic power, liquid film changes are measured. Liquid film thickness are fluctuated in 18, 196cc/min according to capillary wave and cavitation. 25mm diameter of horn has lower liquid film thickness because of big vibration of horn.

평면연삭버어의 가공조건에 의한 영향

이광영,옥철호,서영백,박흥식,전태옥 동아대학교 공과대학부설 생산기술연구소 1998 生産技術硏究所硏究論文集 Vol.3 No.2

This study has been carried out to prevent and decrease the grinding burr under various working conditions; number of grinding passes, depth of cut, hardness of the materials and work speed. Grinding wheel is WA grinding wheel and workpieces are SM45C, SS41, SCM23 and STS 304. The results of tained from this study are as follows; The length of gringing burr increased with increasing grinding passes and it has nothing to do with materials and heat treatment. The size of grinding burr increased with increasing grinding depth and feed speed. The size of grinding burr decreased with increased cross setion and of workpiece. According as the hardness of material was increased, the width of grinding burr decreased conspicuously owing to suppression of plastic zone of burr root part.

열린교육에 대응하는 초등학교 교육환경의 계획기준 연구 : Unit & Block Plan과 Space Program을 중심으로

李承俊,金興起 三陟大學校 2001 論文集 Vol.34 No.2

The purpose of this paper is to examine the educational environments of elementary school among the changes of 21st century. The schools accommodation can be considered under two condition, that is open education and 7th curriculum. For this point, this study is aimed at the first stages analysis of unit plan and space program. Findings of the study are followings ; First, planning of unit class room in Korean open plan Elementary School(above 3.0m² per one person). Second, for the general basis of the elementary school planner, Planning Criteria are suggested by informations/guidelines in the beginning of the design process. Third, proposal about typical space programming(optimum areas of facilities ; 9.0m²per one person)