• 대한치과의사협회지
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• 제21권12호통권175호
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• pp.1005-1010
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• 1983

To study the eruption process of the permanent tooth, esp., 1st molar, the author took 303 cases of oblique cephalogram (Male. 162 cases, Female: 141 cases) from age 3 to 8 yea old children, and observed the vertical change and axial change. The result were as follow: 1. The mesial end of upper 1st molar was closer to the occlusal plane than the distal, and they were erupting toward the occlusal plane by aging. In the case of lower 1st molar, the distal end was closer to the occlusal plane than the mesial and the occlusion showed the tendency to accord with the plane to be settled by aging. 2. Eruption rate of the upper and lower 1st permanent molar increased rapidly at 5 or 6 years of age. 3. Axial inclination of lower 1st permanent molar to the mandibular plane decreased gradually from 3 years of age, except for 6 years of age. There was some increase at 5 or 6 years of age.

• 대한치과교정학회지
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• 제23권3호
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• pp.359-374
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• 1993

At present, many orthodontists regard the root parallelism of the posterior teeth important not only in diagnosis and treatment planning but also for predicting posttreatment stability. To evaluate it, they usually refer to the orthopantomogram. At this study, 97 samples were collected from students of Yonsei University, who have well-proportioned face, Angle's class I canine & molar relationships and no crown axis deviation of the posterior teeth including canines. Reliability of the root parallelism observed from orthopantomogram was evaluated by comparison with $45^{\circ}$ oblique cephalogram. The results were as follows : 1. In comparing the differences between anglular measurements in $45^{\circ}$ oblique cephalogram & orthopantomogram with $5^{\circ}$, those to mandibular plane were significantly less than to occlusal plane in number of items which showed less differences than $5^{\circ}$. 2. Compared the root parallelisms in the orthopantomogram with those in $45^{\circ}$ oblique cephalogram with $1\%$ significance level, parallelism between upper canine & 1st premolar, lower canine & 1st premolar, lower 1st premolar & 2nd premolar, and lower right 2nd molar & 3rd molar showed statistically significant differences. 3. When the significance between the differences of the root parallelism between above two kinds of film and $5^{\circ}$ was verified by two sided paired t-test, more or less large difference was shown between lower right 2nd molar & 3rd molar, a little larger than $5^{\circ}$ between lower canine & 1st premolar, smaller at the rest of them. 4. In $45^{\circ}$ oblique cephalogram, lower canine & 1st premolar showed convergent root arrangements each other, while in orthopantomogram they were divergent each other. All the others except them showed convergency on the upper, divergency on the lower in both films.

• 대한소아치과학회지
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• 제23권2호
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• pp.389-400
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• 1996

In Class II amalgam restoration in deciduous molar, failure rate and incidence of recurrent caries are high as children become older. In order to preserve deciduous molars till the physiologic exfoliation time, stainless steel crown is a choice of the treatment. As a result of a careless treatment, such as overhanging margin, poor marginal adaptation, poor proximal contour and inadequate mesiodistal width give rise to interfering eruption of the adjacent teeth, recurrent caries and chronic gingival irritation and insufficient arch length respectively. In this study, 252 s.s. crowned teeth extracted due to physiologic exfoliation or periapical lesion. The purpose of this study is to analyze the marginal adaptation of stainless steel crown to the deciduous molar in order to obtain better clinical result. The results were as follows : 1. Between the length of s.s. crown and the marginal gap of crown, positive correlations were shown. 2. Largest amount of marginal gap was shown at buccal side in upper deciduous molars and lower first deciduous molar, lingual side in lower second deciduous molar. But no significant diffrence were found statistically compared to second most largest one. 3. Incidence of exposed restoration and recurrent caries were higher in proximal surface than buccal/lingual surface. And extension of restoration below the margin of s.s. crown gives rise to higher rate of recurrent caries. 4. Defect of contour was found in 34%, frequently found in lower 1st deciduous molar and upper 1st deciduous molar. 5. Marginal polishing defects were found in 23%. 6. Ledge was formed in 10% especially in lower 1st deciduous molar and lower 2nd deciduous molar. 7. 16% of the teeth had wear facet due to traumatic occlusion, 7% of them had occlusal perforation.

• 대한소아치과학회지
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• 제8권1호
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• pp.103-117
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• 1981

The data about dental caries obtained from 1438 preschool children (male 797, female 641) in Seoul aged from 3 to 6 were analyzed by their sexes, ages, jaws and teeth surfaces. The results were as follows. 1. dmf rate : 92.63% 2. dmft index : 6.06 dmft rate 30.81 % dmfs index : 11.82 dmfs rate 12.02 % 3. d,m & f rate d rate: 79.45% m rate: 8.15% f rate : 12.40 % 4. dft index : 5.94 5. The order of caries susceptible tooth 1. Lower deciduous 2nd molar 2. Lower deciduous 1st molar 3. Upper deciduous 2nd molar 4. Upper deciduous lateral incisor 5. Upper deciduous cental incisor 6. Upper deciduous lateral incisor 7. Lower deciduous canine 8. Upper deciduous canine 9. Lower deciduous central incisor 10. Lower deciduous lateral incisor 6. Predilection sites of each tooth A) Deciduous central incisor ; Max. : Mesial cavity Mand. : Mesio-distal cavity B) Decidous lateral incisor ; Max. : Mesial cavity Mand. : Distal cavity=Mesial cavity C) Deciduous canine; Max. : Labial cavity Mand. : Distal cavity D) Decidous 1st molar ; Max. : Disto-occlusal cavity Mand.: Disto-occlusal cavity E) Deciduous 2nd molar ; Max. : Linguo-occlusal cavity Mand.: Occlusal cavity 7. All the values in caries criteria in 1981 were somewhat lower than in 1968, but m & f rate were increased.

• 대한치과교정학회지
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• 제20권2호
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• pp.267-280
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• 1990

The purpose of this study was to investigate the force mechanism of Multiloop Edgewise Arch Wire and the intensity and distribution of stresses with vertical and intermaxillary elastics. The obtained results were as follows. 1. When plain wires were inserted and vertical and intermaxillary elastics were used in the upper and lower arch, the stresses of the anterior and posterior ends of wires were observed greatly but the stresses of the premolar were very small. 2. When MEAW were inserted in upper and lower arch, the upper 1st and 2nd premolar and the lower 1st premolar were extruded greatly. 3. In the area of the upper 1st molar and the lower 2nd premolar and the lower 1st molar, any stresses were not observed. 4. The vertical elastic counteracted the intrusion force of the MEAW in the anterior teeth but could not affect on posterior teeth. Using with the Class II elastics, the distal tipping force and extrusion force were exerted in the upper anterior teeth and the intrusion forces of the lower anterior teeth were relieved. Using with the Class III elastics, the extrusion force were exerted in the upper and lower anterior teeth, the distal tipping force were increased in the lower posterior teeth. 5. The Class II elastic counteracted the anterior intrusion force of the MEAW and extruded and tipped mesially the lower 2nd molar. The intrusion force of the MEAW also could not overcome the extrusion force of the class II elastics. 6. When the Class III elastics were engaged, the upper 2nd molar was extruded in spite of the intrusion forces of the MEAW and the extrusion forces of the lower anterior teeth and distal tipping forces in the posterior teeth were observed.

• 대한소아치과학회지
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• 제34권1호
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• pp.27-35
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• 2007

본 연구의 목적은 발거된 기성 금관 수복 유구치를 대상으로 변연 적합도를 관찰 분석하는 것이다. 서울대학교 치과병원 소아치과에서 수거한 3M사의 기성 금관 수복 유구치를 대상으로 하였다. 상악 제 1유구치 42개, 상악 제 2유구치 25개, 하악 제 1유구치 37개, 하악 제 2유구치 28개를 대상으로 기성 금관의 변연에 따라 치근을 절단한 후 단면을 Fine Pix S602 디지털 카메라로 촬영한 후 Kappa image base program을 이용해 우각 부위 및 임의로 20부분의 변연 간격과 전체 기성 금관 면적 중 변연 간격의 면적이 이루는 비율을 측정하여 다음과 같은 결과를 얻었다. 1. 평균 변연 간격은 상악 제 2유구치, 하악 제 1유구치, 하악 제 2유구치, 상악 제1 유구치 순으로 높았다 (P<0.05). 2. 평균 변연 간격 면적의 비율은 치아의 종류에 관계없이 약 20%를 상회하는 값을 보였다. 3. 상악 제 1,2유구치에서는 근심면의 변연 간격이 가장 컸고, 하악 제 1유구치에서는 원심 설면, 하악 제 2유구치에서는 협면에서 변연 간격이 가장 큰 값을 보였다.

• 대한소아치과학회지
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• 제34권2호
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• pp.215-221
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• 2007

본 연구는 혼합치열기 아동에 있어서 연령을 추정하는데 치아의 발육을 이용하면서 치아발육의 평가에 객관적인 수치를 이용하여 방정식을 도출함으로써 간단하게 연령을 추정할 수 있는 방법을 연구하고자 하였다. 이를 위해 2002년에서 2004년까지 전남대학교 병원에 내원한 환아 중 $7{\sim}9$세 어린이 120명을 대상으로 얻어진 파노라마 방사선사진을 이용하여 Mornstad에 의해 제시된 발육치아의 치관 길이, 치근 길이, 치근단공 너비를 측정하여 다음과 같은 결과를 얻었다. 1. 연령과 상관성이 높은 계측치로 남아에서는 제 2대구치 치관 길이, 제 1대구치 치근 길이, 제 1소구치 치근단공 너비가 높은 상관성을 보인 반면 여아에서는 제 2소구치 치관 길이, 제 2대구치 치근 길이, 제 1대구치 치근단공 너비가 높은 상관성을 보였다. 2. 상관성이 높은 계측치를 중다선형회귀분석을 사용하여 역령과 연관시켜 연령추정 방정식을 산출하였다. 남아(개월) = 43.958 + 하악 제 2대구치 치관 길이 ${\times}$ 4.392 + 하악 제 1대구치 치근 길이 ${\times}$ 2.225 - 하악 제 1소구치 치근단공 너비 ${\times}$ 2.046, 여아(개월) = 75.213 + 하악 제 2소구치 치관 길이 ${\times}$ 3.910 + 하악 제 2대구치 치근 길이 ${\times}$ 2.280 - 하악 제 1대구치 치근단공 너비 ${\times}$ 6.217 위 식을 토대로 측정에 사용되지 않은 남녀 각각 10명의 파노라마 방사선사진을 이용하여 나이를 추정한 결과 남아에서는 $-2.1{\pm}6.8$개월의 편차를, 여아에서는 $6.1{\pm}6.2$개월의 편차를 보였다. 이처럼 연령을 모르는 우리나라의 혼합치 열기 아동에서 파노라마 방사선 사진을 이용하여 연령 추정시 위의 방정식을 사용한다면 비교적 정확하게 연령을 추정할 수 있으리라고 사료된다.

• Journal of Oral Medicine and Pain
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• 제6권1호
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• pp.23-34
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• 1981

In order to evaluate the correlation of age with development stage on permanent lower posterior teeth. the author exmined the roentgeregrams in standard films taken by intraoral technic and analysed the development phases of 1358 teeth of 500 males ranging from 9 to 15 years. The development was divided into 7 phases : Crown complete (Cr. C.). Root length 1/4(R. 1/4) Root length /2 (R. 1/2) Apical closure complete (A.C) The obtained results were as follows : 1. The formation of roots in full length on posterior teeth was complete as follow : a. Roots of 1st premolar : 12.72 years b. Roots of 2nd premolar : 12.94 years c. Meral Roots of 2nd molar : 13.38 years d. Distal Roots of 2nd molar : 13.46 years 2. The formation of apical forman of premolar was closured as follows : a. Apical foramen of root of 1st premolar : 13.64 years b. Apical foramen of root of 2nd premolar : 13.93 years 3. As a general rule. the mesial roots of second molar were developed earlier than distal roots of second molar. 4. In the correlation of age with the development stage, the regression equations. the correlation coefficents. and the sample numbers were “Y = 0.8370x + 10.2160, r = 0.71(p<0.01), n = 318”on lower first premolar, “Y = 0.6984x + 10.2148, r = 0.71(p<0.01), n = 385”on lower second premolar, “Y = 0.8810x + 10.2040, r = 0.65(p<0.01), n = 344”on mesial Root of lower second molar, and “Y = 0.7310x + 10.7940, r = 0.66(p<0.01), n = 311”on Distal Root of lower second molar respectively.

• 치과방사선
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• 제26권2호
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• pp.181-189
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• 1996

Ameloblastic odontoma is a mixed odontogenic tumor, which is characterized as being extremely rare, displaying aggressive clinical behavior, resembling a mixed radiopaque and radiolucent radiographic appearance and containing both ameloblastoma and a composite odontoma. Seven-year-old boy complaining of delayed eruption of the left lower permanent 1st molar came to the department of Oral & Maxillofacial Radiology at Chonbuk National University Hospital. The list of our radiographic differential diagnosis included the dental follicle, compound odontoma, complex odontoma and cystic odontoma. The microscopic analysis showed the lesion with the characteristics of an ameloblastic odontoma. The obtained results were as follows; 1. The area was asymptomatic, but the delayed eruption of the left lower permanent 1st molar was observed. Radiographically, well-defined widened pericoronal radiolucency containing several tooth-like radiopacities involving the impacted left lower permanent 1st molar and well-defined round radiolucency containing irregular radiopaque mass were observed. 3. Histopathologically, several tooth-like structures, odontoma components with the area of typical enamel, dentin and pulp, and ameloblastic components with typical follicular ameloblastoma were observed.

• 대한소아치과학회지
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• 제11권1호
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• pp.1-6
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• 1984

The author studied the prevalence of proximal dental caries of deciduous molar by observing intraoral radiographies of 478 children aging from 2 to 5 who visited the Dep. of Pedodontics, Seoul National University Hospital. The following results were obtained; 1. The prevalence of proximal caries of deciduous molar did not show significant difference between male and female, right and left side. 2. Mandibular deciduous molar had higher prevalence than maxillary deciduous molar. 3. The prevalence was increased with age. 4. The prevalence was highest in the distal surface of lower 1st deciduous molar and lowest in the distal surface of upper 2nd deciduous molar.