• 대한치과기공학회지
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• 제42권1호
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• pp.1-8
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• 2020

Purpose: Among the virtual teeth generated by Deep Convolutional Generative Adversarial Networks (DCGAN), the optimal data was analyzed for the number of learning. Methods: We extracted 50 mandibular first molar occlusal surfaces and trained 4,000 epoch with DCGAN. The learning screen was saved every 50 times and evaluated on a Likert 5-point scale according to five classification criteria. Results were analyzed by one-way ANOVA and tukey HSD post hoc analysis (α = 0.05). Results: It was the highest with 83.90±6.32 in the number of group3 (2,050-3,000) learning and statistically significant in the group1 (50-1,000) and the group2 (1,050-2,000). Conclusion: Since there is a difference in the optimal virtual tooth generation according to the number of learning, it is necessary to analyze the learning frequency section in various ways.

• 대한구강악안면병리학회지
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• 제42권6호
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• pp.183-187
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• 2018

The supernumerary tooth which is extra tooth in comparison to normal dentition is one of the developmental problems. The most common type of supernumerary tooth is mesiodens which may cause several complications like delayed eruption, crowding, spacing et al. Moral Incisor Hypomineralization (MIH) describes the clinical appearance of enamel hypomineralization of systemic origin affecting one or more permanent first molars that associated frequently with affected incisors. We report a case of a 6 - year - old boy who visited our clinic for removal of mesiodentes. The patient was diagnosed by mesiodentes and MIH by clinical examination and radiographic examination. Under local anesthesia, Mesiodentes were removed surgically. The demarcated opacities, a feature of MIH, were observed in the removed mesiodentes. After removal of mesiodentes, the maxillary central incisors erupted normally and in order to manage the teeth affected MIH, follow-up and fluoride varnish application were done every 3 months.

• 대한치과교정학회지
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• 제29권4호
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• pp.491-501
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• 1999

본 연구는 석고모형 분석 중 치아크기 측정시 발생할 수 있는 오차를 줄이고 측정의 재현도와 정확성을 향상시키는데 도움이 될 수 있는 방안을 모색하고자 시행되었다. 치아밀집 치열 특징을 지닌 상하악 20조의 석고모형을 대상으로 하여, 5명의 조사자가 각 치아의 근원심 폭경을 디지털 버니어 캘리퍼스를 사용하여 2주 간격으로 3회 측정하여 실험측정치를 얻은 다음, 측정에 이용된 석고모형을 근원심 접촉점 부위에서 개개 치아로 분리한 후, 마이크로미터를 이용하여 측정한 표준치와 비교$\cdot$분석하여 다음과 같은 결과를 얻었다. 1. 3회 측정에 따른 재현도는 조사자별 치아별로 큰 차이를 나타내지 않았다. 2. 표준치와 비교한 계측오차는 조사자별 또는 치아별로 차이를 보였다. 3. 표준치와의 오차는 전치에서 구치로 갈수록 증가하여 제1대구치에서 가장 큰 차이를 나타내었다. 4. 표준치와 비교시 전반적으로 작게 측정하는 경향을 보였으며 이에 대한 치아별, 조사자별 차이가 두드러졌다. 5. 전반적인 오차 발생 정도는 치아밀집 정도와 유의한 상관성을 보이지 않았다. 이상의 결과는 교정증례 분석시 치아크기 계측오차 발생 가능성의 고려가 필요함을 시사하였다.

• Journal of Periodontal and Implant Science
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• 제32권3호
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• pp.501-521
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• 2002

The purpose of this study is to evaluate the influences of the bone morphogenetic protein (BMP) on the healing of periodontal ligament and alveolar bone after replantation of tooth, and to examine the possibility of its clinical application. 45 Sprague Dawley rats weighted about 100 gram were divided into 3 experimental groups by different dose of BMP. All the upper right and left 1st molar were extracted after 5 days feeding of 0.4% ${\beta}$-aminopropionitrile, and right molar were used as experimental group and left molar were used as control group. The root surface of experimental molar were treated with 25,50 and l00ng/ml of human recombinant Bone morphogenetic protein-4 (rh-BMP-4) with micropipet, and 1M Sodium hypochloride were used on control root surface. All the experimental animals were sacrificed as 1, 2, 4, 7 and 14 days after autoreplantation of upper 1st molar into their own position. The maxilla were disected included both side of 1st molar. The collected tissue were processed from demineralization to paraffin embeding as usual procedure, and the specimens were prepared with Hematoxylin-Eosin stain for the light microscopic evaluation. The results of this study were as follows : 1. There was no significant differences between control and experimental site on 1 and 2 days after replantation of tooth. In the case of 4th days, the evidence of tissue regeneration were observed on experimental site to compare the controls. New osteoid were revealed on high concentration of BMP at 7 days after replantation, and it became more obvious at 14 days, 2. The effect of the rh-BMP-4 coated on root surface was revealed slight influences for the prolifertion of cells of periodontium and tissue regeneration as dose-dependent pattern. 3. Bony ankylosis was observed between alveolar bone and root surface due to the remarkable amount of osteoid formation on the 14 days after replantation of root. In the conclusion, it was suggested that topical application of the rhBMP-4 on the root surface has influence on the periodontal ligament and alveolar bone. The application method of BMP on the root should be designed with calculation of proper concentration.

• 대한치과의사협회지
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• 제51권8호
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• pp.459-467
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• 2013

The use of autogenous tooth bone graft material has been commercialized since 2008. Autogenous tooth bone grafts always require that the tooth of the patient be extracted, and thus, the use of graft material are limited in many cases. For solution of limitation in quantity and concurrent use of autogenous tooth bone graft material, the grafting of familial teeth has been suggested. It has the following advantages: the teeth of family members are used as bone graft materials, the genetic composition is identical, and potential genetic and infectious risks can be minimized. Because the teeth of family members are used, a good tissue affinity is obtained, and thus, superior bone generation rates compared to those observed for allogenic or xenogenic bones can be anticipated. We used familial tooth bone-graft materials for alveolar ridge augmentation, socket preservation, and maxillary sinus graft in some cases. In most cases, the impacted third molars of their children were prepared as bone graft material and were used for surgery. In one case, the impacted third molar from the patient's brother was used as bone graft material. We obtained satisfactory result and these cases are reported herein.

• 대한치과교정학회지
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• 제16권2호
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• pp.123-133
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• 1986

The purpose of this study was to collect the information of the straight-wire appliance and to determine the amount of second-order bends in clinical orthodontics. The author analysed the study model of 50 individuals with normal occlusion and results were obtained as follows. 1. The crown angulation was 4 degree in upper central incisor, 7 degree in upper lateral incisor, and 0 degree in lower central incisor and lateral incisor. 2. The crown angulation was 8 degree in upper cuspid and 2 degree in lower cuspid. 3. The crown angulations were 4 degree in upper first bicuspid, upper second bicuspid and lower second bicuspid and 1 degree in lower first bicuspid. 4. The crown angulation was 3 degree in upper first molar, 0 degree in upper second molar, 5 degree in lower first molar and 8 degree in lower second molar. 5. The crown angulations in lower arch were progressively increased from first premolar to second molar. 6. In upper arch, as the crown angulation of one tooth was increased, those of adjacent teeth were increased, too. 7. In the case of lower arch, the crown angulation of cuspid was increased as that of lateral incisor was increased, the crown angulation of second premolar was increased as that of first premolar was increased, and similarity the crown angulation of second molar was increased as that of first molar was increased.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권6호
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• pp.684-689
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• 2007

The aim of this study is to examine the change of the osteoclastic activity in the surrounding bone with or without tooth movement after corticotomy by histologic study. Eighteen male Sprague Dawley rats with an average body weight of 300 g(range 250-350 g) were used. The rats were divided into three groups of six animals. They were operated corticotomy-assisted tooth movement and killed after 1 week, 2 weeks, and 3 weeks after tooth movement. Corticotomy was done in the surrounding of the both upper first molar. A split mouth design was used by referring to the contralateral side as control. After flap suturing, the upper left first molar was moved anteriorly by closed coil spring. The force applied was 1 N. The average of tooth movement of the 1 week group was $0.24{\pm}0.09mm,\;0.20{\pm}0.26mm$ in 2 weeks group and $0.41{\pm}0.39mm$ in 3 weeks group, respectively. The difference between the 1 week and the 2 weeks groups was very small to compare with the 3 weeks group. In the treatment group, the average numbers of cells that positively reacted to TRAP were 14.5 in the 1 week group, 12.0 in the 2 weeks group, and 6.0 in the 3 weeks group. In the control group, the numbers were 8.3 in the 1 week group, 12.8 in the 2 week group, and 1.5 in the 3 week group, respectively. The amount of tooth movement of the 3 week group was about twice as large as those of the 1 week and 2 week groups. From the standpoint of histology, the average number of cells that positively reacted to TRAP was initially larger in the treatment group than in the control group, similar in both group in 2 weeks, and became less in the treatment group in 3 weeks. Additionally, in the control group, their activity of osteoclast was higher in 2 weeks than in 1 week, and decreased rapidly in 3 weeks.

• International Journal of Oral Biology
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• 제35권4호
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• pp.169-175
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• 2010

Cholinesterase (ChE) is one of the most ubiquitous enzymes and in addition to its well characterized catalytic function, the morphogenetic involvement of ChE has also been demonstrated in neuronal tissues and in non-neuronal tissues such as bone and cartilage. We have previously reported that during mouse tooth development, acetylcholinesterase (AChE) activity is dynamically localized in the dental epithelium and its derivatives whereas butyrylcholinesterase (BuChE) activity is localized in the dental follicles. To test the functional conservation of ChE in tooth morphogenesis among different species, we performed cholinesterase histochemistry following the use of specific inhibitors of developing molar and incisors in the hamster from embryonic day 11 (E11) to postnatal day 1 (P1). In the developing molar in hamster, the localization of ChE activity was found to be very similar to that of the mouse. At the bud stage, no ChE activity was found in the tooth buds, but was first detectable in the dental epithelium and dental follicles at the cap and bell stages. AChE activity was found to be principally localized in the dental epithelium whereas BuChE activity was observed in the dental follicle. In contrast to the ChE activity in the molars, BuChE activity was specifically observed in the secretory ameloblasts of the incisors, whilst no AChE activity was found in the dental epithelium of incisors. The subtype and localization of ChE activity in the dental epithelium of the incisor thus differed from those of the molar in hamster. In addition, these patterns also differed from the ChE activity in the mouse incisor. These results strongly suggest that ChE may play roles in the differentiation of the dental epithelium and dental follicle in hamster, and that morphogenetic subtypes of ChE may be variable among species and tooth types.

• 치과방사선
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• 제12권1호
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• pp.27-33
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• 1982

The purpose of this study is to obtain some informations for the differential diagnosis of ameloblastoma from dentigerous cyst by analysis of the radiographic findings of these lesions. The author studied age and sex distribution, the site of the lesion, tooth behavior and several radiographic features of ameloblastoma and dentigerous cyst. The material consisted of 65 patients of ameloblastoma and 37 patients of dentigerous cyst. The results were obtained as followings. 1) The incidence was highest in 2nd decade (29.2%) and total 65 cases consists of 35 males (53.8%) and 30 females (46.2%) in ameloblastoma. 62 cases were found in lower jaw (95.4%) and the highest site of occurence of ameloblastoma was mandibular molar. region 27 cases. (41.5%) 2) In 65 cases of amelobl!!stoma, 18 cases were seen in association with tooth and 15 cases (83.2%) out of those were associated with mandibular molar teeth. Mandibular molar were most frequently involved in dentigerous cyst (11/31 cases, 29.7%). 3) (a) 23 cases (35.3%) of tooth resorption were found in ameloblastoma and 11 cases (29.7%) of tooth resorption were found in dentigerous cyst. (b) 15 cases (23.1%) of tooth migration were found in ameloblastoma and 10 cases (27.0%) of tooth migration were found in dentigerous cyst. 4) Several radiographic features. (a) Monolocular type ameloblastoma were seen in 23 cases (35.4) and multilocular type of ameloblastoma were seen in 42 cases (64.6%). Monolocular type of dentigerous cyst were seen in 33 cases (89.2%) and multilocular type was seen in 4 cases. (b) Monolocular type ameloblastoma showed 20 cases (87.0%) of scalloped border but 32 cases (97.0%) of dentigerous cyst showed smooth border. (c) 34 cases (81.0%) of ameloblastoma showed honey-comb appearance, soap-bubble appearance or mixed appearance. but all 4 cases of dentigerous cyst showed multicystic appearance. (d) 12 cases (52.2%) of monolocular type ameloblastoma showed slightly increased radiopacity in surrounding bone, and 22 cases (66.7%) of monolocular type dentigerous cyst showed sharp osteosclerotic border. 27 cases (64.3%) of multilocular type ameloblastoma and 3 cases (75.0%) of multilocular type dentigerous cyst showed no changes in surrounding bone.

• 치위생과학회지
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• 제20권2호
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• pp.74-81
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• 2020

Background: In the early stages of development, teeth and lingual papillae are induced and developed through special and complex epithelial-mesenchymal interactions. Tooth completion indicates the beginning of the weaning phase, and accordingly, many oral tissues and organs are completed, and it is thought that their developmental completion times are related to each other. The purpose of this study was to clarify the embryonic and neonatal development of the filiform papillae and mandibular molar tooth, and discuss the developmental relationship between these organs by comparing the developmental completion times. Methods: Embryos at embryonic day 15 (EM15), 17 (EM17), and 21 (EM21) and mice at neonatal day 1 (NE1), 5 (NE5), 10 (NE10), and 21 (NE21) were used for experimentation. Tissues dissected from embryos and mice were fixed, and processed for histological analysis. Sections from the tissues were stained with hematoxylin and eosin for observation under a light microscope. Results: Based on the histological analysis results, the developmental process of the lingual epithelium covering the dorsal surface of the tongue was classified into three stages: initiation, morphogenesis, and functional. The development of the filiform papillae begins at EM17; undergoes rapid morphological changes in epithelial cells at EM21, PN1 and PN5, and reaches the functional stage at PN10, which is the sucking phase. Tooth development begins at EM13 or 15 and is completed at NE21 through prenatal and postnatal development. Conclusion: The development of the filiform papillae was initiated late and completed quickly through embryonic and neonatal development in comparison with the mandibular molar tooth. The filiform papillae are considered to play an important role in sucking rather than mastication as it is completed in the sucking phase.