• Anatomy & Biological Anthropology
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• v.26 no.1
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• pp.41-49
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• 2013

Dental epithelial and mesenchymal cells that form the teeth undergo dynamic changes in cell cycle during tooth development and morphogenesis. Although proliferation has been known as a key event during odontogenesis, the cell cycle phases and their relations with the complicated molecular mechanisms of tooth development are not fully understood yet. This study comparatively examined the expression patterns of Ki-67, cyclin A, and cyclin D1 during tooth development in the mouse incisor and molar in order to identify the cell-cycle characteristics during odontogenesis. We found that Ki-67 and cyclin A were expressed in the proliferating cells in the dental epithelial and mesenchymal tissues at the bud, cap and bell stages. Cycln D1 showed distinct expression in the incisor odontoblast region and the enamel knot, in which Ki-67 nor cyclin A was expressed. Our results provide specific information on the cell cycle phases during tooth development that may provide clues to relate them with the complex odontogenic mechanisms. Furthermore, we suggest that our findings enlightened the previous studies on the incisor odontoblasts and the enamel knot during tooth development.

• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.1
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• pp.35-46
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• 2023

Congenitally missing teeth are one of the most prevalent dental anomalies in the oral cavity. In this study, the prevalence, distribution, and symmetry of congenitally missing permanent teeth among 1,865 patients aged 7 to 15 years who visited the Pediatric Dentistry Department of Wonju Severance Christian Hospital from March 2011 to May 2021 and took panoramic radiographs were investigated and analyzed. Most of the patients had one or two congenitally missing teeth, mainly in the second premolars and lateral incisors. Congenitally missing teeth occurred more in the mandible than in the maxilla, and there was no significant difference in prevalence between the left and right sides. Congenitally missing teeth tend to occur symmetrically on the left and right sides and in the maxilla and mandible, depending on the tooth. Early oral examination and radiological examination are required to prevent complications due to congenitally missing teeth, and appropriate interdisciplinary treatment is required.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.618-625
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• 2003

The purpose of this study was to analyze the traumatized primary teeth and investigate the occurrence, types, area, cause, place of trauma to primary teeth and seasonal variation in a hospital population, and to evaluate the interval between injury and treatment. A total 411 children with 745 traumatized teeth participated in this study from 1998 to 2000. The results were as follows : 1. There were slightly more boys than girls giving a male-to-girl ratio of 1.74:1.0. The 1-2, 2-3 year old boys and girls had the highest number of traumatic injuries to their primary dentition. 2. The most common injury was concussion. 3. The majority of traumatized teeth are the upper primary central incisors. 4. Falling down was the most common cause of injury in both sexes. The most of the injuries occurred inside home. 5. 46% of the children visited the dental office within 24 hours after traumatic injury. 6. The most common month was October(12.7%), and June(12.2%), May(11.7%) were followed.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.3
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• pp.394-399
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• 2000

Odontoma is defined as a benign odontogenic tumor containing enmel, dentin as well as cementum. It has come to mean a growth in which both the epithelial and the mesenchymal cells exhibit complete differentiation. Most authorities accept the view today that the odontoma represents a hamartomatous malformation rather than a true neoplasm. The etiology of odontomas is uncertain but hypothesized to involve local trauma, infection, inheritance or mutant gene. The odontomas often cause various disturbances in the eruption and position of the teeth. The steps in removal of an odontoma in close relation to an adjacent impacted normal tooth should comprise 1) removal of odontoma and 2) exposure of the impacted tooth. Orthodontic therapy may be applied. Before treatment, the necessary space for the impacted tooth should be evaluated. If there is lack of space in the dental arch, orthodontic treatment should be carried out before operation.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.4
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• pp.405-417
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• 2010

Previous studies have already shown that mouthguard is effective in protecting jaw bone, teeth and oral tissue against sports trauma. However, other than severe trauma, repetitive force, such as disorders like clenching, cause teeth or oral tissue damage. These kinds of disorders usually present pathologic attrition in the posterior teeth, resorption in alveolar bone, loss of teeth and destruction of occlusion. Wearing a mouthguard is believed to be effective in preventing these disorders. But its effect is not examined thoroughly enough. The purpose of this study is to identify whether mouthguard is effective in reducing strain caused by clenching. Mandibular first molars in the normal occlusal relationship without any history of dental treatment were chosen. Biaxial type strain gauge was placed on the buccal surface of the tooth. Having maximum occlusal force, measured by load cell, as a standard, clenching intensity were divided into three stages; moment of slightly tooth contact, medium bite force (50% of maximum bite force), maximum bite force. Strain occurring in dentition in each stage with and without mouthguard was measured. Changes in strain (on dentition) between each stage and difference in strain, between with or without mouthguard were recorded by PCD-300 analyzer and PCD-30 soft ware. The data was statistically analyzed by Wilcoxon signed rank test. The following results were drawn; Without mouthguard, strain given on dentition increased as the clenching force increased. With mouthguard, strain given on dentition also increased as the clenching force increased. With mouthguard, strain decreased, in all cases of clenching force stages. Data on the moment of slightly tooth contact stage, had no statistical significance. However, with mouthguard, 50-90% of decrease in strain could be obtained in maximum occlusal force, compared to the group without mouthguard. Mouthguard decreased the strain on the dentition, caused by clenching. Therefore, mouthguard seems to be effective in preventing damage on dentition, by acting against clenching, which occurs both consciously and unconsciously during sports activities.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1983.05a
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• pp.17.2-17
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• 1983

The author has experienced a case of follicular cyst affecting the left Maxillar which was diagnosed clinically and histopathologically. This cyst was treated successfully by surgery which was done through sublabial route. I report this case with review of the literature.

• The Journal of the Korean dental association
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• v.45 no.8 s.459
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• pp.456-462
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• 2007

1. 치아의 맹출 장애는 국소적 또는 전신적 원인에 의하여 발생할 수 있다. 2. 맹출 장애가 있는 치아는 공간소실 또는 인접치아의 치근 흡수, 심미적 문제, 함치성 낭종, 종양 등 합병증을 일으킬 수 있다. 3. 맹출 장애가 있는 치아의 상태 및 합병증의 발생 가능성을 평가하여 조기 치료할지를 판단하는 것이 중요하다.

• Journal of Periodontal and Implant Science
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• v.35 no.2
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• pp.413-426
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• 2005

수직 치근파절은 특이성을 나타내지 않기 때문에 치과의사가 정확한 진단을 하기 어렵다. 따라서 수직 치근파절의 임상적 특징, 진단적 증상을 파악하여 향후 근관치료된 치아나 치료되지 않은 치아에서 수직 치근파절의 유발인자와의 관련성 및 고찰을 통해 수직 치근파절의 예방 및 치료에 응용할 수 있을 것으로 생각된다. 연구대상은 조선대학교 부속치과병원 치주과에 내원한 환자 중 최근 2년간 144명의 환자에서 근관치료를 받았거나 받지 않았던 치아 중 임상적 및 방사선학적으로 수직 치근파절로 진단된 156개의 증례를 대상으로 하였다. 모든 불확실한 증례에서 수직 지근파절의 최종 진단은 외과적 탐지를 통해 이루어졌고, 금이 간 치아와 관련될 수 있는 치근파절의 증례의 경우는 제외되었다. 근관치료된 치아와 치료되지 않은 치아, 환자의 나이와 성별, 치아종류 및 파절된 치근부위, 자각증상의 유무를 기준으로 각각의 수치와 백분율로 분류하였다. 수직 치근파절의 증상과 증후별로 분류하였으며, 진단방법에 의한 분류, 치료방법에 따른 분류, 근관 치료 후 수직 치근파절이 발생한 기간에 따른 분류를 시행하고 통계분석을 하여 다음과 같은 결과를 얻었다. 1. 근관치료를 받지 않았던 치아의 수직 치근파절의 발생율은 58%였다. 2. 성별에 따른 발생률에 있어서 남성의 호발양상을 나타내었다. 3. 근관치료된 치아에 있어서 치료되지 않은 치아에 비해 호발연령이 낮았다. 4. 전치부의 수직 치근파절은 관찰되지 않았으며 특히, 강한 교합력을 필요로 히는 구치부에서의 높은 발생율을 나타냈다. 5. 수직 치근파절의 가장 주된 증상 및 증후는 깊은 치주낭 깊이였다. 6. 근관 치료 후 수직 치근파절이 발생한 기간은 평균 5.7년이었다. 7. 다수 증례에 있어서 3개 이하의 결손치를 가졌고, 자각증상이 나타났다. 이상의 결괴에서 한국인에 있어서 근관치료를 받지 않은 치아의 수직 치근파절은 드문 현상이 아님을 알 수 있었고 남성과 구치부에 있어서의 높은 발생율을 알 수 있었다. 그 이유로는 강한 교합력, 딱딱한 음식의 저작습관, 치조골 흡수에 따른 낮은 저항성, 골 유연성의 저하 등으로 여겨진다. 그러나, 수직 치근파절은 아직까지 정확한 진단을 내리기는 여전히 어려운 상태이며, 이를 위한 다양한 진단방법 및 더 나은 연구가 필수적이라 하겠다. 그리고, 향후 보다 많은 증례에 대한 분석, 치주질환에 이환되지 않은 경우의 분석, 치료 후 생존 기간에 대한 고찰 등도 필요하리라 사료된다.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.3
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• pp.328-337
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• 2010

The purpose of this study was to research the traumatized primary teeth and investigate following factors: sex, age, cause, place and time(of the year) of injury, elapsed time, area and type of injury, dental treatment and prognosis. The analysis includes total of 1533 traumatized primary teeth from 758 children aging from 6 months to 6 years(mean age: 2.8) from 2003 to 2007. The result follows : 1. The children of age between 1-2 and 2-3 were involved in the largest number of injuries in both sexes with boy/girl ratio of 1.77:1(p<0.001). 2. Fall and collision were the main causes of traumatic dental injury, especially in younger children(p<0.05). Places of injury occurrence varied: home, outdoors, and kindergarten. Warm climate accounts for frequent outdoor injuries in May, September and October(p<0.001). 3. Most of the children visited dental clinic within 24 hours of the injury(77.6%). From March to September, dental trauma occurrences were distributed evenly, except for Winter period(p<0.001). 4. Upper central incisors were the most commonly affected teeth, and the injuries usually involved 1 tooth or 2 teeth. 5. Periodontal tissue injuries dominated and subluxation was the most common type. Lateral luxation, enamel fracture, intrusion and root fracture followed.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.3
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• pp.499-506
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• 1999

The odontoma is relatively a common benign odontogenic tumor and caused by overgrowth of odontogenic tissues. The recent classification by World Health Organization divides odontoma into 2 groups such as compound odontoma and complex odontoma. Compound odontoma comprises dental tissues, resembling the morphology of a tooth and has predilection for the anterior maxilla. In contrast, complex odontoma has unorganized mass, not resembling the normal tooth and has predilection for the posterior mandible. The etiology of odontoma is unknown and almost asymptomatic. So, it usually is found in routine radiographic examination, and most common presenting symptom is impacted or unerupted permanent teeth and retained primary teeth. It can occurs almost anywhere in jaws. It is desirable that odontoma should be removed by surgical enucleation including follicle and surrounding soft tissues. Considering the age and behavioral cooperation of patient, the development of permanent dentition, the location of odontoma in jaw, the need for the concomitant operative dentistry, operation is performed in outpatient department with/without sedation or under general anesthesia with endotracheal intubation. In this case report, 2 patients with compound odontoma were treated by surgical enucleation including follicle and surrounding soft tissues. One patient, about 5 years old, was treated under general anesthesia and concomitant operative dentistry was performed. The other patient, about 11 years old, was treated under local anesthesia in outpatient department. In 2 cases, after 4 months, surgical defects were filled with new bone and normalization of eruption path of impacted permanent teeth was observed.