• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.1
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• pp.1-13
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• 1999

To study the caries patterns in primary dentition, 719 preschool children, 4-6 years old, were examined for their caries activity(salivary reductase activity) and caries experience of individual teeth. Teeth groups were made by cluster analysis using dft indexes of individual teeth as criteria. The six major teeth groups in the order of dft index from high to low were (1) lower primary molars, (2) upper primary molars, (3) upper central incisor, (4) upper lateral incisor, (5) canines, and (6) lower incisors. There were significant differences in dft index between teeth groups except upper lateral incisor and canines. Upper and lower primary molars showed the highest correlation in dft index, and the next couples were upper central incisors and upper lateral incisors, upper lateral incisor and canines, upper central incisor and canines, upper lateral incisor and upper primary molars, and canines and upper primary molars in descending order. Upper first primary molar showed the greatest differences in dft index between caries activity levels.

• Journal of the korean academy of Pediatric Dentistry
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• v.7 no.1
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• pp.21-32
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• 1980

The purpose of this study is to determine the developmental relationship between the maxillary primary central incisors and their permanent successor. The auther took 315 cases of lateral cephalogram of the children (males were 171, females were 141) Angular change of the teeth and horizontal and vertical linear change were observed. The obtained results were as follows: 1. The inclination of the long axes of both incisor teeth was relatively stable and labio-version of both incisore was significant at 7 years of age. 2. The distance between the incisal edge of the permanent central insisor and the resorbing apex of the primary maxillary central incisor remained within 2mm of each other, 3. Vertical growth of the maxillary anterior portion was greater than horizontal growth from 6 to 7 years of age. 4. There was not a significant sexual difference.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.3
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• pp.387-393
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• 2009

The purpose of this study was to assess the relationship between interdental spaces and proximal caries in maxillary anterior primary teeth. 555 children aged 3-7 inhabit in Iksan were divided into two groups, depending on the presence of interdental space which was detected by a dental explorer. They were determined to have proximal caries if cavity was formed or the enamel surface was softened. The results were as follows : 1. Regarding interdental spaces, 77.4% had primate spaces; 54.4% had developmental spaces between central and lateral incisor, and 39.0% between central incisors. 2. Interproximal caries incidences in right primary canine, lateral incisor, and central incisor were 6.3%, 14.7%, and 33.5%, respectively. Also interproximal caries incidences in left primary central incisor, lateral incisor, and canine were 33.7%, 16.0%, and 4.7%, respectively. 3. Children with more interdental spaces had less caries incidence, but the relationship was weak(r=-0.024). 4. The mean caries incidence was higher in absence of interdental space of maxillary primary incisors than in presence of space. The mean caries incidence with no interdental space was twice as high as that with presence of interdental space.

• Journal of the korean academy of Pediatric Dentistry
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• v.11 no.1
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• pp.145-150
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• 1984

Author have measured the depth of gingival sulcus of the primary teeth. 333 teeth were selected from the children who attended on the department of pedodontic, College of dentistry, Yonsei University, and kindergarten children at Won Ju city aged from 1 year 8 months to 10 year 2 months. 1998 point were measured. The results were as follows. ; 1. Facial surface was the shallowest in sulcus depth compared with other surfaces. It was 1.56 mm. The depth of sulcus in lingual surface was deeper than facial. 2. The deepest part of each surface was mesial and distal, There were no statistical differences between mesial and distal part of the sulcus depth. 3. The mean sulcus depth of each tooth was as follows. Primary central incisor.....1.71mm. Primary canine....1.75mm. Primary second molar.....2.03mm. 4. The mean sulcus depth of upper was 1.86mm, and the lower was 1.76mg. The upper tooth was deeper than lower in sulcus depth. 5. The lower primary central incisor had the shallowest sulcus and the upper 2nd primary molar had the deepest compared with other tooth. 6. There wasn't specific statistical differences between the age groups of primary dentition and mixed dentition.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.2
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• pp.383-399
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• 1998

Tooth development is usually described in four stages such as bud stage, cap stage, bell stage and crown stage. Exact time of appearance of tooth primordia is different among reports, and up to now there is no timetable regarding initial tooth development. To understand the congenital malformations and other disorders of the orofacial region, there is a need to establish a standard timetable on early tooth development. Till now, studies on the tooth development were mainly on later fetuses, and only few reports on early stage. Also, there were no reports on the time when bud stage turns to cap stage, and cap stage to bell stage. In this study, external morphology of face and the early development of the tooth, and transition of bud stage to cap stage, cap stage to bell stage were studied using 27 staged human embryos and 9 serially sectioned human fetuses. The results are as follows: 1. Mandibular region was formed by union of both mandibular arch at stage 15, and maxillary region by union of maxillary arch, medial nasal prominence, and intermaxillary segment at stage 19. 2. Ectodermal thickening which represents the primordia of tooth appeared in mandibular region at stage 13, and maxillary region at stage 15. 3. Bud stage began from mandibular primary central incisor at stage 17, and maxillary primary central incisor at stage 18. And the sequence of appearance was in the mandibular primary lateral incisor at stage 19, maxillary primary lateral incisor at stage 20, mandibular primary canine at stage 22, maxillary primary canine and primary first molar at stage 23, madibular primary first molar and maxillary primary second molar at 9th week, and mandibular primary second molar at 10th week of development. 4. Cap stage began from the primary anterior teeth at 9th week, and primary second molar still had the characteristics of cap stage at 12th week of development. 5. Transition to bell stage started from the primary anterior teeth at 12th week, and primary second molar started at 16th week of development. 6. Trnasition to crown stage started from primary anterior teeth at 16th week, and primary second molar at 26th week of development.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.3
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• pp.352-358
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• 2021

Molar-incisor malformation (MIM) is characterized by malformation in the root with a normal crown. While MIM mostly occurs in the permanent first molar, it has also been reported in the maxillary central incisor and the primary second molar (PSM), but anatomical analysis of the primary teeth with MIM has not been studied to date. In this case report, a patient with MIM was reported, and an extracted PSM with MIM was analyzed with micro computed tomography (CT). A cervical constriction morphology of the cementoenamel junction (CEJ) can be observed in extracted PSM. In micro CT analysis, characteristics such a mineralized plate (cervical mineralized diaphragm) in the CEJ area, complex root canal morphologies, a calcified mass inside the pulp chamber, and constricted pulp chamber of crown portion were observed.

• The korean journal of orthodontics
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• v.50 no.3
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• pp.216-226
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• 2020

Root resorption can be caused by several factors, including contact with the cortical bone. Here we report a case involving a 21-year-old female with Angle Class II, division 1 malocclusion who exhibited significant root resorption in the maxillary right central incisor after orthodontic treatment. The patient presented with significant left-sided deviation of the maxillary incisors due to lingual dislocation of the left lateral incisor and a Class II molar relationship. Cephalometric analysis demonstrated a Class I skeletal relationship (A point-nasion-B point, 2.5°) and proclined maxillary anterior teeth (upper incisor to sella-nasion plane angle, 113.4°). The primary treatment objectives were the achievement of stable occlusion with midline agreement between the maxillary and mandibular dentitions and appropriate maxillary anterior tooth axes and molar relationship. A panoramic radiograph obtained after active treatment showed significant root resorption in the maxillary right central incisor; therefore, we performed cone-beam computed tomography, which confirmed root resorption along the cortical bone around the incisive canal. The findings from this case, where different degrees of root resorption were observed despite comparable degrees of orthodontic movement in the bilateral maxillary central incisors, suggest that the incisive canal could be an inducing factor for root resorption. However, further investigation is necessary to confirm this assumption.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.3
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• pp.406-411
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• 2004

Inverted Impaction of the permanent maxillary central incisor is rare. The causes of impaction are trauma and periapical inflammation of primary maxillary incisor teeth. Treatment options for a inverted incisor is extraction, surgery and orthodontic traction, transplantation, and spontaneous eruption guidance. Treatment depends on the incisor's root development and the space available for eruption. If root development is immature, prognosis would be good. We reported successful treatment for inverted maxially central incisor of proper eruption and normal root development by correction of a eruption route. But further observation will be required to evaluate the final root development state and amount of at tachment gingiva.

• 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.25 no.4
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• pp.717-730
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• 1998

The Finite Element Analysis has been used for stress analysis of prosthesis, orthodontic or orthopedic appliances and filling materials. The primary purpose of the present studying was to evaluate the effectiveness of needle post in promoting the retention and integrity of composite crown restored on the pulpotomized primary central incisor. Three finite element models-natural tooth (Sample I), composite crown with (Sample II) and without (Sample III) needle post-were constructed and the stress distribution within each model were analyzed and compared one another. The results can be summarized as follows: 1. In sample I, the stress was shown to have distributed uniformly throughout the whole tooth even to the alveolar bone. 2. In sample II, the transmission of stress from the crown to the root area was shown to be very poor and irregular. 3. In sample III, the needle post was proved to be very effective in distributing the stress well to the aveolar bone which might help in maintaining the stability of crown restoration.