• Journal of Oral Medicine and Pain
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• v.38 no.3
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• pp.247-253
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• 2013

Renal osteodystrophy(RO) is characterized by skeletal changes in patients with renal disease and developed as a result of alterations in the metabolism of calcium, phosphate and secondary hyperparathyroidism. Bony changes in the craniofacial region include decreased bone density, radiolucent lesions(brown tumors), depletion of cortical bone and loss of lamina dura, but such changes rarely occur in the temporomandibular joint(TMJ). We report an uncommon case of bony changes and pain of both TMJs in a patient with RO. A 41-year-old man with RO came to our clinic due to TMJ pain and sounds. Occlusal change was also reported. Radiographs revealed degenerative changes of the both condyles. The patient had medical history of renal cancer therapy and hemodialysis. The patient was diagnosed with TMJ arthritis of RO and referred for systemic management through medication of calcium and vitamin D and parathyroidectomy. At 15-month follow-up, most of TMD symptoms disappeared and second radiographs revealed that bone density and cortical thickness of the mandible increased and the skeletal outline of the both condyles became relatively clear. As bony changes may begin in the early stage of the renal disease, dentists should be alert to detect the sign of the disease. In addition, it is important to differentiate TMJ arthritis of systemic cause because the treatment protocol is quite different.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.4
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• pp.306-313
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• 2014

Impacted teeth are teeth with a delayed eruption time or that are expected to erupt incompletely. Those teeth can cause a series of potential problems such as root displacement and resorption, periodontal problems in adjacent teeth, referred pain and the formation of cysts and odontogenic tumors. The purpose of this study was to investigate characteristics and treatment of child and adolescent patients younger than 15 years of age that were diagnosed with an impacted tooth who visited the Chosun University Dental Hospital. The impacted tooth, its etiology, treatment and traction period were surveyed through electric medical records, radiographs in 335 patients. We excluded the impacted third molar, supernumerary and deciduous teeth from this study. The most frequently impacted teeth are upper canine, followed by the upper incisor. The most common etiologies of impaction were an abnormal eruption pathway and localized pathologic lesions. The treatment of an impacted tooth was mostly orthodontic traction. The traction period was relatively short in cases with distinct obstacles, with an impacted upper incisor and if patients were younger. An orthodontic traction is considered to be more unfavorable if the patient gets older. Therefore, an early diagnosis and a precise treatment plan through a regular check-ups are mandatory.

• Restorative Dentistry and Endodontics
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• v.27 no.5
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• pp.479-487
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• 2002

복합레진의 중합시 발생하는 수축과 응력은 와동의 형태에 의하여 영향을 받으며 이는 수복재는 물론 접착계면의 물성을 결정하는 요인이 된다. 본 연구는 다양한 C-factor를 갖는 와동에 상아질 접착제 Clearfil SE Bond(Kuraray)를 도포하고 혼합형 복합레진인 Clearfil AP-X(Kuraray)와 미세혼합형의 Esthet-X(Dentsply)를 충전하여 미세인장강도 및 변연누출을 측정 평가함으로써 중합수축이 수복물과 치아계면에 미치는 영향을 평가하고자 시행하였다. 98개의 Bovine 하악전치를 이용하여 표면의 상아질을 #600 SiC paper로 연마한 대조군 및 와동의 넓이를 조절하여 C-factor 2.3, 3.0, 3.7이 되도록 제작한 실험군 와동에 복합레진을 충전한 후 37의 증류수에 24시간 보관하였다. 저속 diamond saw(Buehler)를 이용하여 1mm 두께로 수직절단 후 고속 diamond point(#104 Shofu)를 이용하여 단면적 1mm$^2$가 되도록 hour-glass모양으로 형성하여 시편을 제작하였고, Universal testing machine(EZ-Test; Shimadzu, Japan)에 시편을 부착하고 cross head speed 1mm/min으로 인장력을 가하여 미세인장 결합강도를 측정하였다. 각 C-factor에 따른 변연누출실험을 위하여 복합레진이 수복된 치아를 37$^{\circ}C$의 증류수에 24시간 보관한 후 와동을 제외한 부위에 nail varnish를 도포하고 3mol/L silver nitrate용액에 24시간 암보관한 다음 수세하여 현상액에 24시간 경과시킨 후 치아의 장축에 따라 절단하여 침투된 색소의 정도를 광학현미경상에서 40배로 관찰하였다. 각각의 실험결과는 ANOVA/Tukey's test 및 Kruskal-Wallis non-parametric independent analysis와 Mann-Whitney U test에 의하여 통계 분석하여 다음과 같은 결론을 얻었다. 1. 대조군에 있어서 혼합형 복합레진의 미세인장 결합강도는 미세혼합형에 비하여 높았으며, 실험군 사이에는 유의차를 보이지 않았다. 2.모든 복합레진의 미세인장 결합강도는 와동의 C-factor증가에 따라 감소하는 경향을 나타내었고, 혼합형 복합레진의 실험군은 대조군에 비하여 낮게 나타났으며, 미세혼합형 복합레진에서는 유의차를 보이지 않았다. 3. 절단측 및 치은측 변연부의 미세누출정도는 혼합형 복합레진이 미세혼합형에 비하여 대체로 높게 나타났다. 4. 모든 실험군에서 미세누출은 C-factor증가에 따라 증가하였고 절단측에 비하여 치은측 변연이 높게 나타났으나 통계학적 유의차는 보이지 않았다. C-factor의 변화에 대하여 필러함량과 탄성계수가 높은 혼합형 복합레진이 미세혼합형에 비하여 더 민감한 결과를 보인다. 이는 복합레진 수복시 재료의 선택과 중합수축의 적절한 조절이 중요한 요소임을 시사한다.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.3
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• pp.249-258
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• 2013

The purpose of this study was to investigate how image magnification in dental panoramic radiography is influenced by object position. Five metal balls (4 mm in diameter, 2 for the anterior and 3 for the posterior region on the right side) were placed above alveolar crest of dry skull considering extraction socket and dental arch. Dry skull was radiographed using OP-100D (Instrumentarium Imaging Co., Tuusula, Finland) at proper and displaced position along the sagittal and transverse plane at 3 mm, 6 mm, 9 mm, 12 mm and 15 mm using special mount which can control precise movement. Images were stored in DICOM files and were measured by ruler equipped within INFINITT PACS software (Infinitt Co., Ltd., Seoul, Korea). The mean horizontal magnification was 1.224-1.439 and mean vertical magnification was 1.286 - 1.345 at proper position. Vertical magnification resulted in less variation (1.245-1.418) than horizontal magnification (0.798-6.297) according to the sagittal and transverse displacements. Head positioning is important for linear measurement on panoramic radiography and inclusion of standard object (for instance, metal ball) is helpful to anticipate exact magnification of panoramic radiographs at various location.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.2
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• pp.399-408
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• 1995

The purpose of this study was to obtain information on the clinical and radiographic features of the dentigerous cysts in the jaws. For this study, the authors examined and analysed the clinical records and radiographs of 233 patients who had lesions of dentigerous cyst diagnosed by clinical and radiographic or histopathological examinations. And the obtained results were as follows: 1. Dentigerous cysts occurred the most frequently in the 2nd decade(38.2％) and occurred more frequently in males(67.4％) than in females(32.6％). 2. The most common clinical symptom was swelling of the jaw(33.9％), and the lesions were treated by the method of surgical removal. 3. The type of lesions was mainly observed as central type(72.5％), and size of the lesion was most frequently observed 2 - 2.9cm in the widest length. 4. The lesions were most frequently observed well-defined outline with hyperostotic border(49.8％), and smooth margin(73.4％), and homogeneous lesional radiolucency(79.4％). 5. Cortical thinning and expansion of the lesions(82.0％) were observed, and their direction were most frequently observed toward buccal side(64.0％). 6. The effect on the causative tooth were observed as tooth displacement(41.2％) and delayed root development(l9.3％), and the distance between cemento-enamel junction and lesional wall attachment of the causative tooth was mainly observed as below 2mm(79.6％). 7. The effect on the adjacent tooth were observed as loss of lamina dura(66.8％), root resorption(33.9％), and tooth displacement(31.5％). 8. The effects on the adjacent anatomic structures were observed as displacement of the mandibular canal(46.5％) and maxillary sinus or nasal cavity(72.2％).

• The korean journal of orthodontics
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• v.27 no.1
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• pp.79-89
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• 1997

One of the strenuous problems in orthodontic procedures is postretention stability and retention against relapse. Many investigative trial had been done to disclose the factors associated with relapse and effective prescription to stave off, however, the nature of these jeopardies remained obscure. The objective was to investigate the long-term stability and quantitative changes of dental arches subsequently after Class I nonextraction treatment. Study models,cephalometric headfilms of 26 samples which were taken before, after teatment and postretention were employed to measure the interdental width of corresponding buccal teeth,overbite,overjet and the inclination of incisors and molars. Statistical analysis was carried to compare each measurements across the time period, and followings were brought around. 1. The quantitative amount of relapse in overbite presented positive correlation with the amount of changes through the treatment. 2. Stability of intercanine width was so far secure in the case the expansion had been done through. 3. The amount of changes in intercanine width of the lower regardless of expansion or contraction manifested less than the upper, however, the relapse ratio got high. 4. The upper and lower incisors were likely to be labioversive, and remained stable after retention. 5. The first molars of the upper and lower were conceivably tipped back immediately after treatment and returned to the original angulation. The expansion of intermolar width stayed stable across the time scheme after treatment It was suggested that the maintenance of intercanine width of lower was pertinent to perform the postretention stabilityv and the expansion of dental arch shoed be confined within physiologic boundaries of the patients.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.3
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• pp.550-556
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• 2005

Tooth impaction is defined as a cessation of the eruption of a tooth at the level of the oral mucosa or alveolar bone by any causes. Any tooth in the dental arch can be impacted, but the teeth frequently involved in a descending order are the mandibular and maxillary third molars, the maxillary canines, the mandibular and maxillary second premolars, and the maxillary central incisors. In these teeth, impaction of maxillary incisor occurs in about 0.1-0.5% and major causes are trauma, supernumerary teeth and periapical inflammation of primary maxillary incisor. Delayed eruption of a maxillary central incisor results in midline shift, the space's being occupied by an adjacent tooth and different levels of alveolar height. Treatment options are observation, surgical intervention, surgical exposure and orthodontic traction, transplantation and extraction. These cases were about the patients with delayed eruption of maxillary central incisor. We surgically exposed impacted tooth and guided it into normal position by the orthodontic traction. At the completion of traction, the maxillary central incisor was positoned fairly within the arch and complications such as root resorption were not observed.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.2
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• pp.133-140
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• 2013

Cyclic neutropenia is a hematologic disorder characterized by a marked decrease in the number of circulating neutrophils occurring at regular intervals and after this period, the level of neutrophils usually recovers to a normal range. The clinical symptoms of cyclic neutropenia include fever, malaise, headaches and oral findings associated with painful soft tissue ulceration where lips, tongue and gingiva are typically involved. A 4 year 1 month old boy was presented to the hospital. His chief complaint was mobility of his teeth and swollen gums. The patient had suffered from cyclic neutropenia. Clinical examination revealed evident decay on all primary teeth except for the mandibular anterior teeth and localized alveolar bone loss around mandibullar right and left first primary molars which have mobility was notable. The patient was diagnosed with multiple dental caries, gingivitis and localized periodontitis associated with cyclic neutropenia and treated based on it. The dental treatment, including regular tooth care and appropriate treatment of dental caries or gingivitis, is essential for patients suffering cyclic neutropenia. Especially, proper care at an early stage is needed for young patients to minimize the unwanted consequences for permanent teeth development.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.1
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• pp.122-128
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• 2021

Short root anomaly (SRA) is a rare dental condition with abnormally short and blunt root morphology. It mostly affects maxillary central incisors symmetrically and only has been observed in permanent teeth. A 9-year-old girl was referred from a local dental clinic for short root development in mixed dentition with no symptoms. Radiographic and intraoral examinations revealed SRA on upper and lower incisors and mandibular first molars along with other dental anomalies such as enamel hypoplasia and dens invaginatus. During long - term follow - up for 5 years, her mixed dentition has changed to permanent dentition and generalized SRA was observed in all permanent teeth. Cephalometric radiograph also revealed the calcification between the anterior and posterior clinoid processes described as a sella turcica bridge which was reported associating with dental anomalies. Early diagnosis of SRA is emphasized for successful management and prevention of root resorption and tooth loss. This report aimed to present a rare case of generalized SRA along with other dental anomalies and sella turcica bridging in a female patient through long - term follow - up.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.2
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• pp.140-150
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• 2021

A total of 580 patients, who visited and received an orthodontic diagnosis in the Department of Pediatric Dentistry, Seoul National University Dental Hospital from 2017 to 2019, were investigated in this study. The aim of this study was to evaluate skeletal patterns of pediatric orthodontic patients determined with lateral cephalometric analysis and to analyze the relationship between skeletal pattern and probable associated clinical features. Also, the modality of orthodontic treatment for each skeletal classification was investigated to aid in therapeutic decisions. Patients aged 7 year accounted for the largest age group; 54.2% of patients showed a skeletal class I pattern, 22.2% showed a skeletal class II pattern, and 23.6% showed a skeletal class III pattern. Bi-maxillary retrusion for skeletal class I, retruded mandible with normal positioning of the maxilla for skeletal class II, and retrusion of the maxilla with protrusion of the mandible for skeletal class III were the largest subgroups by skeletal pattern. Brachyfacial type accounted for 55.0% of patients, followed by 31.9% of mesofacial type and 13.1% of dolichofacial type. The prevalence of anterior crossbite in the study was 43.3%, higher than that in previous studies.