• 대한치과의사협회지
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• 제58권7호
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• pp.398-403
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• 2020

Odontogenic anomalies can occur as a result of conjoining defects. These include fusion, gemination and concrescence. The presence of fused teeth can lead to various clinical problems, including the aplasia of permanent successor, the supernumerary teeth and delayed eruption of permanent teeth. In general, the supernumerary teeth associated with fusion is mainly found in the maxillary anterior region. This report describes rare cases of supernumerary tooth associated with fused teeth of mandibular primary lateral incisor and canine. In the first case, fused teeth was extracted. The supernumerary teeth was erupted at canine space. The second case is still being observed. Extraction of fused teeth and observation of supernumerary teeth is planned.

• 대한소아치과학회지
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• 제28권1호
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• pp.142-145
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• 2001

소아치과에 내원한 환아 중에서 치아의 수에 따른 이상을 많이 관찰할 수 있는데 그 중의 하나가 과잉치이다. 과잉치는 정상 치판 (dental lamina)의 과도한 증식의 결과로 발생되며 유치열에서 $0.3\sim0.8%$, 영구치열에서는 $1.0\sim3.5%$의 발생빈도를 보인다. 2 : 1로 남자에게 호발하고 9 : 1로 상악에 호발하며 구치부보다 전치부에 많이 발생한다. 가장 호발하는 것은 상악 정중 과잉치로 상악 중절치 사이에 위치하며 하악 전치부에서는 2%로 낮은 빈도를 보인다. 본 증례는 파노라마 사진 촬영 결과 하악 좌우측 유중절치의 선천적 결손과 4개의 영구 절치외에 2개의 과잉치가 전치부에 관찰되어 발치와 교정치료를 통해 양호한 결과를 얻게 되어 보고하는 바이다.

• 대한치과보철학회지
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• 제27권2호
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• pp.143-154
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• 1989

The purpose of this study was to investigate the mandibular opening and closing movements at mandibular incisor region and clinical rest position in normal subject using the newly developed electric mandibular movement analyzing device, (M.K.G.-K6 diagnostic system, Myo-tronics Inc. Seattle, WA, U.S.A.) The 58 normal subjects, who were students of the College of Dentistry, Chonbuk National University, were selected according to sampling criteria. The obtained results were as follows: 1. There was no significant difference of distribution of opening and closing movement patterns at mandibular incisor region between male and female. There was significant difference between habitual and maximum movement patterns both in sagittal and frontal plane. 2. Although the percentage of distribution of crossover pattern was highest in all cases, but there were significant differences between patterns only at habitual opening and closing movement in sagittal plane. 3. The mean of maximum opening was $47.29{\pm}4.68mm$ in male and $42.15{\pm}4.95mm$ in female. Therefore the mean of maximum opening was larger in male than in female. 4. The mean of maximum laterotrusion in frontal trajectory was larger to the left than to the right. Also the proportion of left deviation at maximum opening position was larger than that of other cases. 5. The mean of maximum opening and closing velocity was higher in male than in female and the mean of closing velocity was higher than that of opening velocity. Also the amount of separation from the centric occlusion was higher in maximum closing velocity than in maximum opening velocity. 6. Clinical rest position was $1.70{\pm}0.99mm$ inferior, $0.74{\pm}0.57mm$ anterior, $0.99{\pm}0.51mm$ right from centric occlusion and the A/V ratio was 1:2.7.

• 대한소아치과학회지
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• 제25권2호
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• pp.383-399
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• 1998

Tooth development is usually described in four stages such as bud stage, cap stage, bell stage and crown stage. Exact time of appearance of tooth primordia is different among reports, and up to now there is no timetable regarding initial tooth development. To understand the congenital malformations and other disorders of the orofacial region, there is a need to establish a standard timetable on early tooth development. Till now, studies on the tooth development were mainly on later fetuses, and only few reports on early stage. Also, there were no reports on the time when bud stage turns to cap stage, and cap stage to bell stage. In this study, external morphology of face and the early development of the tooth, and transition of bud stage to cap stage, cap stage to bell stage were studied using 27 staged human embryos and 9 serially sectioned human fetuses. The results are as follows: 1. Mandibular region was formed by union of both mandibular arch at stage 15, and maxillary region by union of maxillary arch, medial nasal prominence, and intermaxillary segment at stage 19. 2. Ectodermal thickening which represents the primordia of tooth appeared in mandibular region at stage 13, and maxillary region at stage 15. 3. Bud stage began from mandibular primary central incisor at stage 17, and maxillary primary central incisor at stage 18. And the sequence of appearance was in the mandibular primary lateral incisor at stage 19, maxillary primary lateral incisor at stage 20, mandibular primary canine at stage 22, maxillary primary canine and primary first molar at stage 23, madibular primary first molar and maxillary primary second molar at 9th week, and mandibular primary second molar at 10th week of development. 4. Cap stage began from the primary anterior teeth at 9th week, and primary second molar still had the characteristics of cap stage at 12th week of development. 5. Transition to bell stage started from the primary anterior teeth at 12th week, and primary second molar started at 16th week of development. 6. Trnasition to crown stage started from primary anterior teeth at 16th week, and primary second molar at 26th week of development.

• 대한소아치과학회지
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• 제32권4호
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• pp.644-648
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• 2005

과잉치는 정상치판(dental lamina)의 과도한 증식의 결과로 발생되어 가족적 성향을 보이며, 쇄골두개이형성(Cleidocranial dysplasia), Gardner 증후군 등의 여러 질환과 관련되어 나타나기도 한다. 그 빈도는 유치열에서 $0.3{\sim}0.8%$, 영구치열에서 $1.0{\sim}3.5%$이고, 남성에서 호발되며(2 : 1), 상악에서 더 많이 발생한다(9 : 1). 상악에서는 mesiodens라고 불리는 중절치 사이의 위치가 가장 흔한 부위이고, 그 다음은 fourth molar와 측절치 부위이다. 하악에서는 소구치 부위가 가장 흔한 부위이고 전치부위에서는 약 2%로 매우 드물게 발생한다. 과잉치의 만기 잔존은 치간 이개, 인접한 치아의 맹출 장애, 치근 흡수 등을 야기하고 과잉치와 관련되어 함치성 낭종이 발생될 수 있으므로 조기진단과 적절한 치료가 중요하다. 본 두 증례는 비교적 드물게 나타나는 하악에 발생한 과잉치로, 하악 전치부와 소구치부에 발생한 과잉치를 발거하고 교정치료를 시행하여 양호한 결과를 얻었기에 보고하는 바이다.

• 대한치과보철학회지
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• 제45권5호
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• pp.633-643
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• 2007

Statement of problem: Recently there are on an increasing trend of using implants-especially in edentulous mandible of severly alveolar bone recessed. Purpose: The aim of this study was to analyze the displacement and stress distribution of various mandibular implant-retained overdenture models supported by two implants in interforaminal region under the occlusion scheme load. Material and method: FEA models were made by the 3D scanning of the edentulous mandibular dentiform. The three models were named as Model M1, M2, and M3 accord ing to the position of implants: M1, Lt. incisor area, M2, Canine area, and M3, 1st Premolar area. Inter-implant angulation model was named as M4. Conventional complete denture was named M5 and used as a control group. Ball implant and Gold matrice were used as a retentive anchors. The occlusion type loads were applied horizontally over each tooth. Results: 1. In mandibular implant retained overdenture Canine Protected Occlusion type load resulted in higher levels of stress to the implants and female matrices than other types of loads. 2. The overdenture model M1, with implants in lateral incisor areas resulted in lower stress concentration to the implants and female matrices than other models. 3. In mandibular implant retained overdenture the stresses of the implant and female matrice were lower in mesially inclined implant than these of parallel installed implant. Conclusion: Lateral incisor areas could be the best site for the implants in mandibular implant-retained overdenture. The mandibular implant retained overdenture models mentioned above showed to the lowest stress to the implants and female matrices.

• 대한치과보철학회지
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• 제29권3호
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• pp.141-170
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• 1991

This study was to analyze the displacement and the magnitude and mode of distribution of the stresses in the lower overdenture, the mucous membrane, the abutment teeth and the mandibular supporting bone when various abutment designs were subjected to different loading schemes. For this study, the two-dimensional finite element method was used. The models of overdenture and mandibe with the canine and the second premolar remaining, were fabricated. In the first design, a 1 mm space was prepared between the denture and the dome abutment with the height of 2 mm(OS). In the second design, a contact between the denture and the occlusal third of the dome abutment with the hight of 2 mm was prepared(OC). In the third design, a 0.5 mm space was prepared between the denture and 8 degree tapered cylindrical abutments with the height of 7 mm(TS). In the fourth design, a contact between the denture and the occlusal two thirds of the conical abutments with the height of 7 mm was prepared(TC). In order to represent the same physiological condition as the fixed areas of the mandible under loading schemes, the eight nodes which lie at the mandibular angle, the coronoid process and the mandibular condyle were assumed to be fixed. Each model was loaded with a magnitude of 10 Kgs on the first molar region (P1) and 7 Kgs on the central incisor region (P2) in a vertical direction. The force of 10 Kgs was then applied distributively from the first premolar to the second molar of each motel in a vertical direction (P3). The results were as follows: 1. The vertical load on the central incisor region(P2) produced the higher displacement and stress concentration than that on the posterior region(P1, P3). 2. The case of space between abutment and denture base produced higher displacement than that of contact, and the case of long abutment produced higher displacement than that of short abutment because of low rigidity of denture base. 3. The magnitude of the torque and vertical force to the abutment teeth and the stress distribution to the denture base was higher in the telescope coping than in the overdenture coping. 4. The vertical load on the central incisor region(P2) produced higher equivalent stress in the mandible than that on the posterior region(P1, P3). 5. The case of space between abutment and denture base produced better stress distribution to the farther abutment from the loading point than that of contact. 6. In case of sound abutment teeth, the type of telescope coping can be used, hilt in case of weak abutment, the type of overdenture coping is considered to be favorable generally.

• 대한소아치과학회지
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• 제36권4호
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• pp.580-585
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• 2009

소아치과 영역에서 치아수의 이상은 흔히 관찰할 수 있으며, 그 중 대표적인 것의 하나가 과잉치이다. 과잉치의 발생원인에 대해서는 여러가지 가설이 있으며 유전적 또는 환경적 요인에 의해 치배 형성기의 정상 치판이 과도하게 증식하여 발생되는 것으로 알려져 있다. 과잉치가 가장 흔하게 발생되는 부위는 상악에서는 절치부로 그 빈도는 80-94% 정도로 보고되고 있고 그 다음으로는 구치부와 소구치부 순서로 나타난다. 상악에 비해 하악에서는 대부분 소구치 부위에서 발생되며 절치부에서는 전체 과잉치 발생빈도 중 단지 1-2% 이하로 매우 낮은 빈도로 발생되는 것으로 보고되고 있다. 이 증례는 드물게 나타나는 하악 절치부에 2개의 과잉치가 있다는 주소로 내원한 만 6세 남아에서, 임상 및 방사선학적 검사 결과 하악 절치부에 정상치와 크기와 형태가 비슷한 정상치형의 과잉치 2개를 포함하여 6개의 절치가 존재하는 것이 관찰되었다. 발치할 치아의 정확한 진단 및 결정을 위해 컴퓨터 단층 촬영을 시행하였고 발치 후 하악 전치부의 정상적인 배열을 위해 치아 맹출에 대한 주기적 정기 검진 후 교정적 평가와 치료를 진행할 예정이다.

• 대한치과교정학회지
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• 제47권3호
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• pp.176-185
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• 2017

Objective: To evaluate the relationship of gingival thickness (GT) and the width of keratinized gingiva (WKG) with different malocclusion groups and the level of crowding. Methods: A total of 187 periodontally healthy subjects (121 females and 66 males) who presented at the Faculty of Dentistry in $Y{\ddot{u}}z{\ddot{u}}nc{\ddot{u}}$ Yil University for orthodontic treatment were enrolled in the study. The individuals involved in the study were divided into three groups; Angle Class I malocclusion, Angle Class II malocclusion, and Angle Class III malocclusion. Each group was classified as mild, moderate, or severe according to the level of crowding. WKG was determined as the distance between the mucogingival junction and the free gingival margin. GT was determined by the transgingival probing technique. Factorial variance analysis and the Duncan multiple comparison test were employed to identify the extent to which a difference was apparent between the groups according to these parameters. Results: It was determined that teeth in the mandibular anterior region display the thin gingival biotype. WKG and GT were observed as being higher at the mandibular incisor teeth in the severe crowding group and at the mandibular canine teeth in the mild crowding group. The GT of the mandibular right central and lateral incisors was found to be thinner in the Angle Class III group. Conclusions: Within the limits of this study, the results demonstrate that, there is no significant relationship of WKG and the mean GT in the mandibular anterior region according to the Angle classification.

• 대한소아치과학회지
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• 제23권2호
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• pp.429-449
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• 1996

An objective 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 prevalence 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 prevalence of individual dental anomalies were as follows : supernumerary teeth 15.6%, congenitally missing teeth 6.6%, fusion 2.2%, odontoma 0.35%, microdontia 1.2%, macrodontia 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 group I and other groups, there was negative correlation, especially group I and group II. 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 highest incidence in primary dentiton, while mandibular lateral incisor in permanent dentition. In the mandible(72.5%), this site showed higher prevalence than in maxilla. In the case with deciduous congenitally missing teeth, the prevalence of successive permanent congenitally missing teeth was about 33.9%, the incidence was highest 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 prevalence of successive permanent congenitally missing teeth was 39.9%, while that of successive permanent fused teeth was 2.7%. And the highest rate of the prevalence (40.3%) appeared in fusion of mandibular deciduous lateral incisor and canine. 7. In the case of odontoma, the prevalence was higher in maxilla(78.6%) and anterior region(82.7%) than mandible and posterior region.