• Restorative Dentistry and Endodontics
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• v.31 no.2
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• pp.79-85
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• 2006

To evaluate the effect of vital tooth bleaching agent and alcohol pretreatment on dentin bonding, flat dentin windows were produced on the buccal side of the crowns of fifty-five extracted, human premolars. A bleaching gel, $Opalescence^{(R)}$ with 10% of carbamide peroxide (Ultradent Product, USA) was daily applied on the teeth of three experimental groups for six hours for 10 consecutive days, while teeth of a control group were not bleached. After 6 hours of bleaching gel application the specimens were washed and stored in saline until the next day application. After application of $One-step^{(R)}$ dentin bonding agent (Bisco, USA), $Z-250^{(R)}$ resin (3M-ESPE, USA) was bonded to dentin with a mount jig. Shear bond strength was measured with an Instron machine (Type 4202, Instron Corp., USA) after 24 hours. The results were analyzed using one-way ANOVA and Duncan's multiple range test at p < 0.05. Immediate bonding group showed significantly lower bond strength than un-bleached control group (p < 0.05). Ethanol-treated group showed significantly higher bond strength compared to immediate bonding group (p < 0.05). However, the bond strength of the ethanol treatment group was lower than that of the un-bleached control group (p < 0.05). There were no significant difference in shear bond strength between the 2-week delayed bonding group and the ethanol-treated group (p > 0.05) and between delayed bonding group and un-bleached control group (p > 0.05). In the condition of the present study. it seems that alcohol pretreatment after bleaching procedure can reduce the adverse effect of vital bleaching agent on dentin bonding.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.1-6
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• 2000

Dentinogenesis imperfecta is an inherited disorder of dentin formation, usually exhibiting an autosomal dominant mode of transmission. Type I dentinogenesis imperfecta occurs in patients afflicted with osteogenesis imperfecta. Type II dentinogenesis imperfecta is not associated with osteogenesis imperfecta. Type III dentinogenesis imperfecta (Brandywine type) occurs in a racial isolate area in the state of Maryland. In all three types, teeth of both dentitions are affected with variable clinical appearances. The teeth are opalescent with the color ranging from bluish-gray to brown to yellowish. The dentin is abnormally soft, providing inadequate functional support to the overlying enamel. Although the enamel is normal, it fractures or chips away easily, exposing the occlusal and incisal dentin. The exposed soft dentin often undergoes rapid and severe functional attrition. The teeth exhibit bulb-shaped crowns with constricted cementoenamel junctions and thin roots. The teeth will exhibit varying stages of obliteration of the coronal and root pulpal chambers. The cementum, periodontal ligament and supporting alveolar bone appear normal. The enamel is normal. The mantle dentin remains nearly normal, whereas the remaining dentin is severely dysplastic. The dentinal tubules are disoriented, irregular, widely spaced, and usually larger than normal.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.3
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• pp.483-488
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• 2003

Nasopalatine duct cyst(NPDC) is the most common non-odontogenic cyst in the oral area and is thought to be originated from the epithelial remnants of the nasopalatine duct. Many etiologic factors have been proposed for the NPDC; trauma to the region during mastication or from ill fitting dentures, bacterial infection, and spontaneous proliferation of tissue. The majority of cases are seen between the ages of 40th and 60th and it is rare in children. Surgical enucleation is the recommended treatment for NPDC, usually under general anaesthesia. A 9-year-old boy was refered to the chosun university pedodontics clinic that this child who has anterior palatal swelling is in routine check. In this case, swelling was presented at the bottom of the anterior nasal cavity as well as in the labial aspect of the upper alveolar ridge. It was so large that we treated it by marsupialization and obturator was put. This patient is on the continuous observation. We treated the child who had NPDC by marsupialization, and got the successful results such as rapid bone regeneration and the consistency of incisor vitality.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.2
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• pp.270-274
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• 2009

Dentigerous cysts generally encompass the crown of an unerupted tooth. These cysts are usually solitary. They are the second most common odontogenic type of cysts following radicular cysts, and are frequently associated with impacted mandibular third molars or maxillary canines. Most multiple cysts found in the jaw are odontogenic keratocysts associated with the nevoid basal cell carcinoma syndrome, mucopolysaccharidoses and cleidocranial dysplasia. Although a single dentigerous cyst is well documented in the medical literature, including the prevalence, treatment and prognosis, multiple dentigerous cysts without any systemic symptoms is unusual. Furthermore, cases involving both the maxilla and mandible are especially rare. We present the case of an 11-year-old boy with nonsyndromic multiple dentigerous cysts associated with a mandibular second premolar and a maxillary canine. The treatment was conservative and included marsupialization and eruption guidance. Further follow up is planned to rule out additional problems and the possible identification of a syndrome.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.1
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• pp.96-101
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• 2009

Regional odontodysplasia(ROD) is relatively rare localized developmental anomaly of tooth formation in which hard tissue is affected. The maxilla is typically affected than the mandible, and especially the maxillary left quadrant is the most commonly involved. Females are affected twice as often as males, and there is no association with race. Its etiology remains undetermined, but local circulatory disorders, somatic mutations, virus infections, local trauma, hyperpyrexia, irradiation, metabolic disturbances, and hereditary transmission are considered as possible etiologic factors. The affected teeth are likely to be small, hypoplastic, brown, and grooved. Eruption failure or delay is frequently seen as well as abscess or fistulae formation in absence of caries. Radiographically, there is a lack of contrast between the enamel and dentin, both of which are less radiopaque than unaffected counterparts. Moreover, enamel and dentin layers are thin, giving the teeth a “ghost-like appearance”. The pulp chambers and canals are large, the roots seem like to be short and indistinct. A 2-year-3-month old boy came to the department of pediatric dentistry, Yonsei University, with the chief complaint of delayed eruption and abnormal tooth shape on the lower left quadrant. He was diagnosed as regional odontodysplasia based on the clinical and radiographic findings.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.4
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• pp.766-770
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• 2008

Gingival fibromatosis is a rare condition characterized by varying degrees of gingival hyperplasia. Gingival fibromatosis usually occurs as an isolated disorder or can be associated with a variety of other syndromes. It usually appears at the time of eruption of permanent dentition but, can develop at the time of eruption of the primary dentition and rarely at birth. It may deform palatal contour and subsequently restrict the tongue movement, resulting in interference during speech and mastication. In addition, it incapacitates maintenance of normal lip closure. A 14-month-old girl visited the department of pediatric dentistry, Yonsei University Dental Hospital, for the congenital gingival overgrowth. There was no one in the family, who showed similar pattern of gingival growth. The intraoral clinical examination revealed generalized severe gingival enlargement throughout the maxillary and the mandibular arches. Enlarged gingival tissue was pink and had firm consistency. She was referred for chromosomal analysis, which confirmed absence of any known syndrome. Under local anesthesia, "Punch-biopsy" was performed on the labial area, and the specimen was histologically diagnosed as gingival fibromatosis. For she did not have any medical problem nor familiar history, she was diagnosed as having idiopathic gingival fibromatosis. Regarding her age and behavior, close follow-up was decided.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.1
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• pp.22-28
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• 2011

Purpose: This article attempted to examine how teeth for restoration is made in a clinical practice and utilize it as future educational material of teeth formation and basic data for additional research. Materials and methods: This experiment investigated the models sent to milling center for production of zirconia crowns. After scanned with Lava CAD/CAM System (3M ESPE, Seefeld, Germany), they are measured on 'ImageJ (version 1.32j, National Institutes of Health, USA)' program and compared and analyzed. Convergence angle from mesio-distal surfaces and bucco-lingual surfaces of each teeth are measured. Also, bucco-lingual diameter of the region lowered as much as 0.4 mm from incisal edge in anterior teeth except canines.(This measure is defined as the Peak 0.4) The analysis of data between each group was conducted by Windows SPSS statistic program, and was proved significant on 95% confidence level by independent t-test, one-way ANOVA and multiple analysis (Sheff${\'{e}}$ test). Results: The mean value of convergence angle was $18.67^{\circ}$ It is ranked as molar ($26.70^{\circ}$) > premolar ($16.87^{\circ}$) > anterior teeth ($14.81^{\circ}$) in the order of mesio-distal convergence angle; anterior teeth ($22.32^{\circ}$) > molar ($20.93^{\circ}$) > premolar ($15.41^{\circ}$) in the order of bucco-lingual convergence angle. The mean value of Peak 0.4 was 1.18 mm. Conclusion: Convergence angle of abutment of zirconia all ceramic crown has difference depending on the location in the arch. Due to the nature of production of zirconia all ceramic crown, convergence angle of abutment and line angle finishing degree can have an effect on internal suitability of restoration.

• The korean journal of orthodontics
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• v.36 no.3 s.116
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• pp.207-217
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• 2006

Although ceramic brackets have been used widely for improved esthetics during treatment, ceramic brackets have some inherent problems; brittleness, attrition of the opposing teeth and high frictional resistance. This study was performed to understand the frictional resistance of the ceramic brackets, as well as to be a helpful reference for finding the solutions to the problem of frictional resistance. Three different kinds of brackets were used; metal bracket, polycrystalline ceramic brackets with a metal slot to reduce the high frictional resistance and monocrystalline ceramic brackets. The brackets were tested with a $.019{\times}.025$ stainless steel wire with a second order angulation of $0^{\circ}\;and\;10^{\circ}$, and the static and kinetic frictional forces were measured on the universal testing machine. The results of this study showed that the ceramic brackets, especially the monocrystalline ceramic bracket without a metal slot, generated higher frictional resistance than the metal bracket, and the frictional resistance was increased as the angulation between the bracket slot and the wire increased. Therefore, the development of the ceramic bracket with reduced frictional resistance and the prevention of excessive crown tipping during orthodontic treatment will lead to the simultaneous attainment of more efficient and improved esthetic treatment goals.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.4
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• pp.657-661
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• 2005

Various chemotherapeutic agents have been recommended for pulpotomy of primary teeth, and there are formocresol, ferric sulfate, and calcium hydroxide. Of those, formocresol has fixation effect of pulp tissue and high clinical success rate, so it is most commonly used agent. But formocresol has strong cytotoxic effects, thus many articles reported displacement and loss of permanent successor, amelogenesis imperfecta, mutation by general absorption, possibility of cancer induction. Recently, it has been reported that leakage by imperfect temporary sealing when FC-soaked cotton was inserted into the root canal caused necrosis of surrounding tissues. and that necrosis of alveolar bone related to the use of excessive formocresol. In this case, 2nd primary molar of upper left jaw was treated using formocresol in local clinic, but extracted because of lasting pain. Furthermore, symptoms didn't disappear so patient was refered to us. The patient was 8-year-old male, had foul odor from oral cavity and circular alveolar bone necrosis around the permanent successor' crown. Thus sequestrectomy was operated and observed through 19 months after operation, we found normal root development of permanent successor but no complete regeneration of alveolar bone defect and attached gingiva. Lesion of periodontal tissues by formocresol is irreversible, so we have to confirm the indication in using formocresol and pay attention to complete temporary sealing.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.262-266
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• 2004

The parathyroid hormone plays a major role in the metabolism of calcium and phosphorus. In hypoparathyroidism the parathyroid glands are atrophied or absent associated with autoantibodies against parathyroid tissue. Pseudohypoparathyroidism is a metabolic disease caused by the disturbance in peripheral action of parathormone, but parathormone level is normal. In general, patients with pseudohypoparathyroidism have short stature, round face, brachydactylia, obesity, mental retardation, cataracts & ectopic calcifications on soft tissues. Dental manifestations are enamel hypoplasia, delayed eruption, blunting of root apex, hypodontia, pulp calcification, thickened lamina dura, excessive caries & malocclusion. In this case, intraoral examination showed enamel hypoplasia on the erupted permanent teeth & hypermobility on the remaining deciduous teeth. From the radiographic view severe dental anomalies were observed on canines and shortening and blunting of root apex was observed on mandibular incisors. Pathologic root resorption was also observed on deciduous teeth.