• 대한치과의사협회지
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• 제50권6호
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• pp.322-328
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• 2012

Ectopic eruption of the permanent first molar is defined as the eruption of the tooth in an abnormal position or orientation. It may causes distal root resorption and premature exfoliation of the adjacent primary second molar and uncontrolled space loss is followed. Prolonged partial impaction of the permanent molar may also cause undetected caries or abscess formation of the neighbor teeth. The purpose of this paper is to provide a brief review regarding the etiology, classification, and different management techniques for correcting ectopic eruption of permanent first molar.

• 한국콘텐츠학회논문지
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• 제10권7호
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• pp.285-296
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• 2010

이 연구는 상악 대구치 임상치관의 형태 및 크기를 계측하기 위해 건강한 영구치열을 갖는 C보건대학생 100명을 대상으로 다음과 같은 결론을 얻었다. 1. 임상치관의 교두높이, 치관폭, 치관두께는 좌우 대칭관계를 보였다. 2. 협면구의 강한 발육은 우측 제1대구치에서 우세함을 보였고, 협면소와는 우측 제1대구치에서 높은 출현률을 보였다. 3. 4교두형은 좌 우측 제1대구치에서 100%, 좌 우측 제2대구치에서 각각 78%, 75%로 나타났다. 4. 4교두형일때 원심설측교두 크기는 좌, 우 대칭관계를 보였다. 5. 교두정간 거리는 좌 우측 제1,2대구치 모두 근심 교두정간 거리가 컸다. 6. 카라벨리 교두의 발달은, 좌 우측 모두 제1대구치에서 높은 발육을 보였다. 7. 사주융선의 출현률은 우측 제1대구치에서 87.0%, 우측 제 2대구치에서는 73.0%의 출현율을 보였고, 좌측 제1대구치에서는 88.0%, 좌측 제2대구치에서는 73.0%로 이는 제1대구치에서 약한 치관우식증을 가지고 있는 사람 때문인것으로 사료되었다. 8. 근심변연융선결절 출현율은 좌 우측 모두 제1대구치에서 높은 출현율을 보였다. 원심부 결절은 우측 제1대구치에서 16.0%, 우측 제 2대구치에서 26.0%였고, 좌측 제1대구치에서 14.0%, 좌측 제2대구치에서 21.0%의 출현율을 보였다.

• 대한치과교정학회지
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• 제23권2호
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• pp.263-273
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• 1993

The purpose of this study was to analyse the center of resistance of the maxillary first molar using the 3-dimension finite element method. An extracted maxillary first molar of normal shape and average root length was selected and sectioned every 1.5mm parallel to the cementoenamel junction. Each section was traced and digitized to construct 3-D finite element model of the maxillary first molar. After a certain magnitude of counterbalancing moment(M) was applied to the tooth, a varying single force(F) of distomesial direction was applied to a certain point of th tooth until the tooth was translated. The force producing translation(Ft) was substituted to the equation ${\Delta}d=M/Ft$ to calculate the center of resistance of the maxillary first molar. And reducing the alveolar bone level 1.68mm, and 3.36mm below to the cementoenamel junction, the tooth movement was analysed to see the effect of reducing the alveolar bone level to the location of the center of resistance. The results were as follows ; 1. The center of resistance of the maxillary first molar was 3.72mm apical, 1.10mm buccal, and 0.71mm mesial to the geometric center of the horizontally sectioned surface at the cementoenamel junction. This point was 0.36mm apical, 1.20mm buccal, and 0.71mm mesial to the trifurcation point, indicating that it was not on the tooth root. 2. As the alveolar bone level was reduced, the center of resistance of the maxillary first molar was moved to the apical direction.

• 대한소아치과학회지
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• 제43권3호
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• pp.284-291
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• 2016

본 연구는 이소맹출한 상악 제1대구치의 자율적 수정 가능성을 예측할 수 있는 진단적 기초를 제공하기 위하여 정상군과 가역성과 비가역성 이소맹출의 차이점을 비교 평가하고자 후향적으로 분석하였다. 상악 제1대구치와 인접치아 간의 장축과 교합평면간의 각도를 파노라마상에서 측정하였고, 제2유구치의 교합관계도 조사하였다. 이소맹출군과 정상군은 통계학적으로 유의한 차이를 보였지만(p < 0.05), 가역성과 비가역성 이소맹출군 간에는 통계학적으로 유의한 차이는 없었다(p > 0.05). 제2유구치와 제1대구치 그리고 제2대구치 치배 간의 각도는 정상군에 비해 이소맹출 군에서 작은 값을 보였으며, 근심 계단형이 이소맹출군에서 더 높은 빈도로 관찰되었다. 본 연구의 결과를 토대로 상악 제1대구치의 이소맹출은 상악 제1대구치와 제2대구치 치배의 각도와 관련이 있으며, 이소맹출한 상악 제1대구치는 상악 저성장의 3급 부정교합 환자에서 보다 빈번하게 나타나는 경향이 있는 것을 알 수 있었다.

• 대한소아치과학회지
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• 제24권4호
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• pp.776-780
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• 1997

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

• Imaging Science in Dentistry
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• 제38권2호
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• pp.95-101
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• 2008

Purpose: To assess the positional relationship between the maxillary sinus floor and the apex of the maxillary first molar using cone beam computed tomograph (CBCT). Materials and Methods: CBCTs from 127 subjects were analysed. A total of 134 maxillary first molars were classified according to their vertical and horizontal positional relationship to the maxillary sinus floor and measured according to the distance between the maxillary sinus floor and the maxillary first molar. Results: Type III (The root projected laterally on the sinus cavity but its apex is outside the sinus boundaries) was dominated between 10 and 19 years and type I (The root apex was not in contact with the cortical borders of the sinus) was dominated (P<0.05) between 20 and 72 years on the vertical relationship between the maxillary sinus floor and the apex of the maxillary first molar. The maxillary sinus floor was located more at the apex (78.2%) than at the furcation (21.3%) for the palatal root. The distance from the root apex to the maxillary sinus floor confined to type I was increased according to the ages (P<0.05). Type M (The maxillary sinus floor was located between the buccal and the palatal root) was most common (72.4%) on the horizontal relationship between the maxillary sinus floor and the apex of the maxillary first molar. Conclusion: CBCT can provide highly qualified images for the maxillary sinus floor and the root apex of the maxillary first molar.

• 대한치과의사협회지
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• 제57권11호
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• pp.654-663
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• 2019

This case report describes the management of a 30-year-old woman with hopeless mandibular first molars and right maxillary second premolar. The treatment plan included mandibular second and third molar protraction after extraction of mandibular first molars. Mini-implants were placed between roots of first and second premolar. Sliding mechanics with lever arm was used to prevent inclination of molars. A good functional occlusion was achieved in 38 months without clinically significant side effects. Most of the extraction space of mandibular first molar was closed by protraction of second and third molars. The skeletal Class II pattern was improved by counterclockwise rotation of mandible through reduction of wedge effect. Mandibular molar protraction with orthodontic mini-implants in adequate cases would be a great alternative to prosthetic implant and reduce the financial and surgical burden of patients.

• 대한소아치과학회지
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• 제44권1호
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• pp.56-63
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• 2017

국소적, 전신적 요인을 동반하지 않는 제1대구치의 맹출 지연은 해당 치아의 발육 지연을 동반한다. 본 연구의 목적은 제1대구치의 발육지연의 임상적 양상 및 동반하는 다른 치아의 발달 이상에 관하여 고찰하는 것이다. 국소적 요인이 없이 제1대구치 맹출 지연을 보이는 건강한 어린이 40명의 파노라마방사선 사진 분석을 시행하였다. 2명의 평가자가 Nolla 방법을 이용하여 해당 치아의 발육지연 여부, 해당 분악의 제2대구치 발육 이상 여부 및 제3대구치를 제외한 다른 치아의 선천적 결손 여부에 관하여 조사하였다. 제1대구치의 발육지연은 상악에서 호발하였고, 여성에게서 양측성 이환, 남성에게서 편측성 이환이 많이 관찰되었다. 제1대구치의 발육지연이 있는 환아는 유의하게 높은 선천적 결손치의 유병률을 보였으며, 이환된 분악의 제2대구치는 모두 발육 지연 혹은 선천적 결손의 이상을 보였다. 본 연구결과 제1대구치의 발육지연은 다른 치아의 선천적 결손과 밀접한 연관이 있는 것으로 나타났다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제48권1호
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• pp.63-67
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• 2022

Controversies exist regarding the need for prophylactic extraction of mandibular third molars in patients who plan to undergo orthognathic surgery. An 18-year-old male patient was diagnosed with mandibular prognathism and maxillary retrognathism with mild facial asymmetry. He had a severely damaged mandibular first molar and a horizontally impacted third molar. After extraction of the first molar, the second molar was protracted into the first molar space, and the third molar erupted into the posterior line of occlusion. The orthognathic surgery involved clockwise rotation of the maxillomandibular complex as well as angle shaving and chin border trimming. Patients who are missing or have damaged mandibular molars should be monitored for eruption of third molars to replace the missing posterior tooth regardless of the timing of orthognathic surgery.

• 대한치과교정학회지
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• 제17권2호
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• pp.311-320
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• 1987

The purpose of this study was to investigate the growth changes of maxilla and mandible and position changes of first permanent molars of growing children The author analyzed the data using cephalometric roentgenogram of 43 boys and 39 girls age of 6 to 11 with normal occlusion The obtained results were as follows 1 The eruption path of maxillary and mandibular first permanent molar superimposed on TM-ANS and mandibular plane shows individual variation 2 There was no correlation between horizontal and vertical changes of maxillary first permanent molar, but positive correlation in mandibular first permanent molar 3 As the eruption, the forward changes of mandibular first permanent molar was significantly greater than that of maxillary first permanent molar 4 As the ages were increased, there were irregular growth changes of maxilla and mandible 5 Growth changes of lower anterior facial height was relatively stable 6 N-S-${\bar{6}}$ was stable after age 7.