• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.2
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• pp.329-334
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• 2007

The infection of primary teeth occurs by caries or trauma. But, if it is not treated on time, the complication may occur such as enamel hypoplasia, discoloration, impaction, displacement and dilaceration of permanent successors. The periapical lesion on primary tooth could displace the permanent successors in any direction. Treatment options of displaced tooth are observation after extracting the primary teeth, surgical exposure orthodontic traction, transplantation and extraction. In these cases, displacement of permanent central incisor caused by the periapical lesion of primary teeth was observed. The spontaneous eruption after extraction of primary teeth was expected considering degree of displacement, development of root and direction of eruption. This case report shows spontaneous eruption of displaced permanent tooth germ was achieved with periodic examination after extraction of primary teeth.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.3
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• pp.475-480
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• 2009

An infraoccluded tooth is a tooth that has failed to erupt to be in line with adjacent teeth in the vertical plane of occlusion. Multiple complications can occur as a result of an infraoccluded tooth. Tipping of neighboring teeth, loss of space opposing teeth elongation, increased susceptibility to dental caries and abnormal eruption path, impaction and rotation of permanent successor are the consequences of infraocclusion of primary molar. Therefore, early diagnosis and treatment is the key to prevent the complications. Treatment options can be periodic follow-up, temporary restoration or extraction of the infraoccluded tooth depending on the presence of the successor, the extent of infraocclusion and the extent of tilting of the neighboring teeth. The infraoccluded primary molars with permanent successors present tend to exfoliate normally. However, failure to do periodic check up of the infraoccluded teeth may lead to serious complications. In these cases, surgical extractions are often necessary after space regaining and space maintainers should be placed until the eruption of the permanent successors are completed.

• Journal of Technologic Dentistry
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• v.33 no.4
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• pp.331-337
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• 2011

Purpose: The purpose of this study was to impact of force system change in finger spring that add helical coil one round on orthodontic force. Methods: The following conclusions were drawn from the experiment conducted after bending 90 samples with a CNC wire forming machine while changing the height and lumen size to 1mm - 3mm - 5mm and 2mm - 3mm - 4mm respectively in the coil of the force system in finger spring added with one wheel of helical coil of 18-8 stainless steel round wire (${\Phi}0.5mm$, spring hard) from Jinsung Co. in domestic market under the following conditions: Laboratory name = Instron 5942; Temperature($deg^{\circ}C$) = 18.00; Humidity(%) = 50.00; Rate 1 = 10.00000 mm/min; Compressive extension = 5.0mm. Results: When Coil height is 1, 3, 5mm and lumen size is 2, 3, 4mm reduce finger spring as mean value of compressive extension occasion maximum load(mN) increases as coil height rises, and lumen size grows to 5.0mm. And was expose that compressive load(mN) increases as coil position of finger spring rises and increase as lumen size is decrescent. Conclusion: As the adherence height of coil was raised from 1mm through 3mm to 5mm, compressive load increased. As the lumen size increased from 2mm through 3mm to 4mm, compressive load decreased. Therefore, these results suggest that it is desirable to lower the coil height and enlarge the lumen size to enhance the biomechanical efficiency of finger spring when manufacturing the finger spring for removable orthodontic devices.

• Journal of Technologic Dentistry
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• v.34 no.4
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• pp.381-390
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• 2012

Purpose: The goal of this study is to investigate the correlation of orthodontic treatment with self-esteem and how orthodontic treatment has an effect on university student's self-esteems by investigating and analyzing the difference in self-esteem of each general characteristic and the difference in self-esteem according to the existence or nonexistence of malocclusion and orthodontic treatment for adult university students. Methods: This study conduced a survey for 420 university students including dental related department, department of health and department of non-dental health in two universities located in Taegu, Gyeongbuk-do province from May 15, 2012 to May 30, 2012, and in 420 questionnaires of the investigated 420 target students, total 400(95.2%) questionnaires except for the questionnaires with falsely or erroneous responses were used for study analysis. Results: In the relations of general characteristic with self-esteem, for self-esteem by each gender, male student showed higher, for self-esteem by residential area, the university student residing at metropolitan area showed higher, for self-esteem by financial status, high class and middle class students in home financial status showed higher, for self-esteem by face shape, the student with triangular face shape showed higher, and in the relation of self-esteem with orthodontic treatment, the university student who is getting orthodontic treatment showed higher self-esteem statistically significantly. Conclusion: For gender, male university student, for residential area, the university student residing at metropolitan area, the high class university student in financial status, the university student with triangular face shape, and the university student who is getting orthodontic treatment showed statistically significantly higher self-esteem.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.2
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• pp.256-261
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• 2000

Trauma to the tooth is the most common accidents in pediatric dentistry and tooth fracture occurs frequently. Fracture is classified into crown fracture, root fracture, and crown-root fracture which involves both. Also, it is classified into simple or complicated fracture depending on whether the pulp is exposed or not. When the fracture is extended down to the subgingival level following the long axis of the root, or when more than 1/3 of the root is involved, extraction is the primary treatment. But alternative treatment such as extruding the root fragment with orthodontic force and restoring it, or intentionally extracting the tooth and replanting it to a position which it can be restored. This is a case report on intentional replantation of a traumatized maxillary central incisor with crown-root fracture of a patient with mixed dentition. The teeth was extracted and immediate endodontic treatment, retrograde filling and resin restoration were carried out.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.1
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• pp.82-87
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• 2011

The pulp infection of primary tooth is often caused by dental caries or trauma. But, if it is not managed properly, it can be produce the periapical lesion. The periapical lesion can cause some complications such as enamel hypoplasia, displacement, root dilaceration and impaction. Treatment options of displaced permanent successor are clinical and radiological follow-up after extraction of primary teeth, surgical opening, orthodontic traction, transplantation and extraction. In these cases, the premolars with abnormal eruption path caused by periapical lesion of the primary tooth have shown successful spontaneous eruption just as a result of extraction of infected primary tooth and space maintenance.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.4
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• pp.407-412
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• 2011

Adenomatoid odontogenic tumor(AOT) is an infrequent odontogenic tumor which arise in the jaw. It was considered as a variant of ameloblastoma. The adenomatoid odontogenic tumor is clearly benign and, in contrast to the ameloblastoma, present a very low recurrence. It most often appears in the canine region of the maxilla. The adenomatoid odontogenic tumor is frequently asymptomatic, however it may cause painless swelling. The radiological findings of adenomatoid odontogenic tumor frequently share characteristics of dentigerous cyst and unicystic ameloblastoma. Conservative surgical enucleation and curettage are the treatment of choice. In this case a 10-year-old child was presented with mandibular right lateral incisor in unerupted. Radiographically, the tooth was impacted and a radiolucency was seen in the area. The lesion was enuclated without extraction of the tooth. Bracket was attached on the tooth for orthodontic extrusion installed. Histopathologically adenomatoid odontogenic tumor was revealed.

• Journal of the korean academy of Pediatric Dentistry
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• v.23 no.2
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• pp.549-558
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• 1996

Light-cured orthodontic composite resin has been widely advertised recently for use in bonding brackets. However, the curability of light-cured resin when light waves are diffused through metal brackets in questionable. The purposes of this study were to evaluate shear bond strength and failure patterns of visible light-cured resin(Lightbond) and chemically cured-resin(Mono-Lok 2), and to determine the relative value of light-cured resin as an alternative to conventional chemically cured resin. Each of the two resins was tested on twenty extracted human first premolars. Standard edgewise metal brackets were bonded to the teeth in accordance with the manufacturers' recommendation. After bonding, the teeth were stored for 24 hours at $37^{\circ}C$, 100% humidity. The shear bond strength was tested with a universal testing machine(Instron 4302), at 0.5mm/min crosshead speed. After debonding, brackets and enamel surfaces were examined with a scanning electron microscope and a stereoscopic microscope. The results were as follows : 1. Metal brackets bonded with Lightbond showed statistically higher shear bond strength than metal brackets bonded with Mono-Lok2. 2. The predominant failure site in Lightbond was the enamel-resin interface, and in Mono-Lok 2 it was the resin itself. 3. Enamel cracks were not found in any specimen. The above results suggest that direct bonding of metal brackets to enamel with light-cured resin bonding agent can be used effectively in clinics.

• Journal of Technologic Dentistry
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• v.36 no.4
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• pp.239-246
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• 2014

Purpose: The purpose of this study was to compare the tensile strength and mechanical properties of orthodontic wire joints made by gas soldering and laser welding, with and without filling material, to identify the effectiveness and potential clinical application of laser welded orthodontic wires. Methods: Three joint configurations of orthodontic wire were used: diameter 0.9 to 0.9 mm wire, diameter 0.9 to 0.5 wire and diameter 0.9 mm wire to band. The joints were made using three different methods: gas soldering, laser welding with and without filling material. For each kind of joint configuration or connecting method 7 specimens were carefully produced. The tensile strengths were measured with a universal testing machine (Zwick/Roell, Instron, USA). The hardness measurements were carried out with a hardness tester(Future-Tech Co. Tokyo, Japan). Data were analyzed by AVOVA(p= .05) and Turkey HD test(p= .05). Results: In all cases, gas soldering joints were ruptured on a low level on tensile bonding strength. Significant differences between laser welding and gas soldering(p< .05) were found in each joint configuration. The highest tensile strength means were observed for laser welding, with filling material, of 0.9 to 0.9 mm wire joint. Conclusion: In conclusion, the elastic modulus and tensile strength means of laser soldering with filling material were the highest, and the tensile strength means of laser soldering were higher than those of gas soldering.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.2
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• pp.311-316
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• 2006

A scissors bite in the posterior teeth occurs when the upper teeth are positioned totally or unilaterally buccal to the lower teeth in centric occlusion. This malocclusion can result from either excessive width of maxilla, deficient width mandible, or combination of both. The malocclusion can lead to hindered growth of jaws or to asymmetry between the jaws, Besides, the severe lingual inclination of the mandibular posterior teeth prevents adequate mastication. Thus, the scissors bite is in need of immediate interceptive orthodontic intervention. The common treatments of the scissors bite is to expand the mandibular arch: fixed or removable appliances. In our clinic, we made a success in treatment of the scissors bite using the Schwarz appliance. We treated the scissors bite using the lower Schwarz appliance for a mean observation period of 21 months. The subjects were 2 boys, aged 4 years.