• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.22 no.2
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• pp.215-219
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• 1992

The author ovserved a case of dentinogenesis imperfecta in a 8-year-old and a 9-year-old brother with complaints of abnormal morphologic changes of the teeth. 1. Clinically, yellowish brown colored teeth, fractured crown and numerous retained root tips of deciduous teeth with severe attrition were observed in the both deciduous and permanent dentitions. 2 Radiographically, small-sized teeth, partial or complete obliteration of the pulp chambers and pulp canals in the anterior teeth, partial obliteration of the pulp chambers and thin enamel in the permanent tooth germs were observed. 3. The familial history was their father has been lose his teeth early.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.16 no.1
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• pp.25-30
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• 1986

The author studied the magnification ratio of teeth length in orthopantomogram through intraoral film taken by standardized paral1eing technique. In this study, intraoral radiograph and orthopantomogram were taken in 2 cases of dry skull and 36 adults (504 teeth). 1. The obtained results were as follows: In case of dry skull, the magnification ratio of standard films was 4.6% to 5.9% and that of Orthopantomograph 5 was 15.1% to 33.1%. The magnification ratio of to the standard film was 9.2% to 26.5% 2. In case of adults, the magnification ratio of Orthopantomograph 5 to the standard films was 9.5% to 24.6%. 3. There were no significant difference in magnification between left and right. 4. Anterior teeth had lesser magnification than posterior teeth. 5. It was considered that teeth length showed in Orthopontomograph 5 was magnified 15.4% to 31.3% than actual teeth length.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.1
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• pp.173-178
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• 1997

As one of the developmental disturbances in shape of teeth, an accessory root may involve any teeth, but has very rare frequency in the deciduous teeth. Because it is possible to diagnose the accessory root only by use of the radiographs, it is important to detect this root early by carefully examining the radiographs. The accessory root produces several problems such as abnormal exfoliation of deciduous teeth, eruption abnormality of successive permanent teeth, infection due to residual root during tooth extraction, and incomplete pulp treatment, and therefore it is necessary to have a continuous follow check-up to prevent these problems.

• Journal of Technologic Dentistry
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• v.13 no.1
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• pp.21-26
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• 1991

The mesiodistal crown diameters and crown length of the permanent anterior teeth have been studied and analyzed about the mean size, S.D, S.E etcs from stone models of 100 Korean male and 74 female. From the study, the following conclusions were made : 1. Statistical differences of left and right teeth were not found in the mesio distal crown diameters and crown length of the permanent anterior teeth. 2. The mean values of mesiodistal crown diameters of permanent anterior teeth were slightly larger in male than in females and statistical differences of males and females were found in maxillary right central incisor, mandibular left canine, mandibular right lateral incisor and mandibular right canine. 3. The mean values of crown length of permanent anterior teeth were slightly larger in male than in female and statistical differences of males and females were found in mandibular left canine, mandibular right canine. 4. Mesiodistal crown diameters and crown length of maxillary left lateral incisors and right lateral incisors of female are larger than that of male.

• The korean journal of orthodontics
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• v.29 no.1 s.72
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• pp.129-136
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• 1999

Etiologies of the molar teeth impaction are cyst, supernumerary teeth, ankylosis by replacement resorption, abnormal eruptive path, improper orthodontic treatment, etc. If the impacted teeth were untreated, the sequallae was as follows : loss of occlusal function, loss of permanent tooth, extrusion of opposite tooth, root resolution of adjacent teeth. The most important factor of solution of impacted teeth is treatment timing & proper application of orthodontic forces.

• The Journal of the Korean dental association
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• v.54 no.7
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• pp.492-500
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• 2016

Crown fractures are a common type of dental injuries and very frequently occurred on maxillary anterior teeth, area of requiring a rapid aesthetic recovery. Crown fragment reattachment is a simple and conservative method to restore the fractured teeth. The technique promotes esthetic outcomes as utilizing natural contour, shade, surface texture of teeth and gives mechanical similarity in terms of wear-resistance. Also it gives emotional positive responses to patients and requires less of chair time and costs. This case report presents two cases of crown fragment reattachments on maxillrary anterior teeth, including one complicated crown fracture and one uncomplicated crown fracture. If the fragment is available in cases of crown fractures, reattachment of fragment can be regarded as a predictable alternative. However, it is all the time important that a close conversation informing the patients about the limitations and prognoses of this treatment option.

• The Journal of the Korean dental association
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• v.16 no.1 s.104
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• pp.37-42
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• 1978

A study on the impacted teeth of the anterior segment was carried out. The data for this study were compiled form 1739 outpatients of the Department of Orthodontics, College of Dentistry, Seoul National University. The following conclusions were obtained; 1. The frequency of the impacted teeth of the anterior segment was 2.8% and the frequency of male was 4.0%, that of female was 2.1%., respectively. 2. The order of occurrence of the impacted teeth in the anterior segment was maxillary canine mesiodens, maxillary central incisor, maxillary lateral incisor, mandibular canine. 3. The etiologic factors of the impaction were the space deficiency for eruption, cleft palate, the prolonged retention of deciduous teeth, dentigerous cyst. 4. The favorable results of treatment and prognosis were obtained from the impacted teeth of the normal shape after surgical exposure and adhered the plastic attachment and inducted them into the dental arch.

• The Journal of the Korean dental association
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• v.44 no.2 s.441
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• pp.123-132
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• 2006

Patients who have impacted tooth are found commonly in orthodontic treatment. Although it is difficult to find the cause of impacted teeth, the most common, causes are prolonged retention of the deciduous teeth, trauma, aberrant sequence of eruption, lack of space and deficiency of Vitamin D. Impacted teeth may lead to esthetic and functional problems and root resorption of adjacent teeth, so we should treat it as soon as possible. Commonly used treatment method is the following: After surgically uncovering of the impacted teeth, a bond of orthodontic appliance is established, and orthodontic traction is started with a removable or fixed appliance. We used the modified lingual arch with a soldered auxiliary appliance in lingual arch for traction of lower impacted teeth. The modified lingual arch could control the magnitude and direction of the applied force with one-arch treatment, and also could give continuous force to impacted tooth without patient patient cooperation. We achieved good results with the modified lingual arch.

• The Journal of the Korean dental association
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• v.50 no.6
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• pp.304-311
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• 2012

Eruption of the teeth can be disturbed by crowding, ectopic eruption path, retention for pathologic condition of follicle and periodontal ligament, local disturbances in the innervation, and delayed eruption for overlying obstacles in the eruption path. Eruption disturbance of permanent posterior teeth is taken with diverse therapeutic approaches according to the patient age, cooperation of patient, tooth position and maturity, degree of impaction, clinical features, and repercussion on the neighboring teeth. However, delayed treatment usually results in less favorable outcomes. Therefore, In order to prevent this situation, periodically radiographic examinations during the early mixed dentition period and early diagnosis of eruption disturbances of permanent posterior teeth are recommended.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.91-92
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• 2006

High precision speed reducer which has a cycloid or involute teeth profile, used to in Robot. In this study, suggest to a new teeth profile, which has basically a triangle teeth profile. We had a stress analysis compare to convenient speed reducer for teeth profile. We has a good results in new teeth profile for strength, stress and stiffness.