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수치지형모델에 있어서 자료점 밀도가 토공량의 정확도에 미치는 영향
권현,손홍규,유복모 연세대학교 산업기술연구소 1987 논문집 Vol.19 No.1
Earthworks play a major role in many civil engineering projects. Due to this fact, in most cases, particularly in undeveloped areas, improving the accuracy of the earthwork calcvlation is very important. In this study, the cut-and-fill volumes for each of two roads were first computed using a data spacing. The results of model cases were analyzed to determine the accuracy requirements for various types of digital elevation data to achieve a certain level of accuracy in volumetric computation, and six levels of elevation accuracy were studied.
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.
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.