• Journal of the korean academy of Pediatric Dentistry
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• v.8 no.1
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• pp.47-53
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• 1981

Author have studied with electron microscope on the effect of biscuit solution dissolved in natural saliva on the enamel surface of the primary teeth. Four of the teeth were natural primary teeth and the other four teeth were treated in acidulated phosphate fluoride during four minute. The obtained results were as follows; 1. The pH value of the solution was decreased according to the time passed, and gradually became 3.75 at the end of 48 hours. 2. Natural teeth appeared normal enamel surface appearance during first 12 hours, and at 24 hours, it appeared some degree of decalcified appearance near the enamel rods and surfaces. 3. The decalcified appearances of the enamel surfaces of the fluoride treated teeth were not significant compared with the fluoride untreated teeth. 4. Streptococci of the enamel surface were increased according to the time passed.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.3
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• pp.444-449
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• 2002

The term 'impaction' is used to designate a tooth which remains unerupted in the jaw beyond the time at which it should normally be erupted. The main causal factors are local (lack of space, ectopic positions of teeth, supernumerary teeth, cyst, the occurrence of infectious process in the eruption path, traumatic facial injury etc.). Systemic and genetic disorders, however, may have primary failure of eruption and retarded eruption as additional symptoms (cleidocranial dysplasia, osteopetrosis etc.). Most cases of impacted teeth reported in the literature are of permanent teeth. The absence of primary teeth occur rarely whereas impaction of second primary molars is more numerous than all other impactions. Impaction due to primary failure of eruption must be distinguished from the secondary infraocclusion. The etiology of impaction of primary teeth is probably related to early ankylosis of primary teeth, but it is not clear. Failure of eruption of primary teeth may cause a number of complications, such as interference with development and eruption of succedaneous teeth, formation of cyst, and damage to adjacent teeth. This study is to report cases of primary failure of eruption in the primary dentition.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.4
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• pp.749-760
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• 1998

The main purpose of this study was to evaluate the effect of dentin with various pretreatment application time on the dentin surface structure and the bond strength of glass ionomer restorative matrials between primary and permanent tooth. There are difference of composition, structure and pretreated effect of dentin conditioning between the primary and permanent teeth. Inspite of thease fact, we used the same application time of permanent tooth. This study intends to determine the most effective application time using SEM analysis of the surface change by dentin conditioning. Forty five intact primary and permanent teeth were splited mesiodistally with seperating diamond disk. Each eight specimens were prepared for shear bond strength test. (randomely devided eight group as follows:) group I conditioning for five seconds group II conditioning for ten seconds group III conditioning for fifteen seconds group IV conditioning for twenty seconds Additional specimens were prepared to SEM analysis. The result are as follows: 1. Primary teeth are higher shear bond strength in group I and group II. 2. There was no statistically significant difference between primary and permanent teeth in group III and group IV. 3. In SEM analysis, smear layer removal by dentin pretreatment of primary teeth was faster than permanent teeth. Primary teeth may require shorter pretreatment time of dentin for G-I restoration than that of permanent teeth.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.3
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• pp.407-412
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• 2002

The primary cause of missing teeth vary depending on the region. The loss of posterior teeth is mainly due to dental caries, whereas that of the anterior teeth occur primarily due to trauma at the age of standing and walking and secondarily from the rampant dental caries. Particularly, reduction of the arch length in the cases of premature loss of primary teeth may compromise the eruption of succedaneous permanent teeth. This may result in crowding and impaction of the permanent teeth, and asymmetry of arch, thus a careful consideration for space maintenance should be made in such cases. Space maintainer is required in the case of premature loss of primary posterior teeth, because space loss result from the approximate and centrifugal movement of the neighboring teeth. Generally, in the case of primary incisor, space loss occurs when 1) tooth contact is relevant, 2) crowding in primary dentition is present, and 3) a primary incisor is lost before the eruption of primary canine. Contrarily, in the case of primary dentition with interdental space, space loss will not be observed, mostly when a primary incisor is lost after the eruption of primary canine. Thus, using a space maintainer in cases of premature loss of primary incisor has been introduced primarily not for the purpose of space maintaining but for an aesthetic purpose, prevention of parafunctional oral habits such as tongue thrust, and of pronunciation. Additionally, few case studies have been reported of space loss in cases of premature loss of primary incisor. This study is to report cases of the space loss following the premature loss of primary incisors observed in children.

• 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.37 no.2
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• pp.260-266
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• 2010

Trauma to the primary teeth may have an effect on the successive permanent teeth. Thus, the treatment plans should be focused on safety of their permanent teeth. The degree of developmental disturbances in those permanent teeth depends upon many factors including the age of the children, developmental conditions of the affected teeth, types and severities of trauma and time interval from the moment of trauma to the initial treatment the patients received. The complications of the effected permanent teeth vary from the mild enamel hypoplasia to the premature finishing of teeth development. In this study, children whose ages were 33 months, 5 years, and 26 months presented the developmental disturbances to their permanent teeth, which resulted from the trauma to the primary teeth: the intrusion, the avulsion, and the subluxation. There showed a mild complication in the case of subluxation resulting in enamel hypoplasia, but, the more severe complication of the root dilacerations occurred in the case of intrusion. Furthermore, the 5-year-old patient whose primary dentition was near in transition period to the permanent one, the more complicated problem such as stop of root development of the permanent teeth was resulted from the avulsion. Thus, one should assume that the types of trauma and the age of the children at the moment of trauma have different effects on those successive permanent teeth. In conclusion, when the trauma that causes changes in the position of primary teeth happened, it is important to arrange an appropriate treatment procedure considering the types of trauma and the developmental conditions of the permanent teeth.

• Journal of the korean academy of Pediatric Dentistry
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• v.8 no.1
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• pp.65-75
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• 1981

The author have studied on the pulp responses to the electric pulp stimulator (Pyo-Cure)(R) in the primary molar age from 4 to 11 of the 186 children (male 100, female 86). The total numbers of teeth used in this study were 1096. The results were as follows ; 1. The difference in responses between the teeth of the male and female was not statistically significant. 2. The difference in responses between the teeth of the right and left sides was not statistically significant. 3. The difference in responses between the teeth of the upper and lower jaws was not statistically significant. 4. The responses of the teeth in the older age is higher than its of the early age. 5. Inspite of advanced root resorption of the primary molars, except severe root resorption, the responses of the teeth was higher according to increasing the age. 6. The responses of the teeth were decreased severely in the primary molars as it becomes exfoliation time.

• Journal of the korean academy of Pediatric Dentistry
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• v.10 no.1
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• pp.67-76
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• 1983

The state of pulp and dental hard tissue during the process of resorption and shedding of 104 non-carious primary teeth was assessed by histomorphologic study. The teeth were extracted from the Korean school children aged 5 to 15 and classified into preshedding, shedding, delayed shedding groups according to the age of the child at the time of extraction, The results were as follows: 1. The inflammatory cell infiltration in primary pulp tissues occurred in 61.5% of observed teeth and were increased in the order of preshedding, shedding and delayed shedding stages. 2. The odontoclasts were appeared in 43.3% of observed teeth and were increased in the order of preshedding, shedding and delayed shedding stages. 3. The polymorphonuclear leukocytes and odontoclasts couldn't be observed in the exfoliated primary pulp tissues before the process of resorption has involved the root surface about 1.8mm subjacent to the cemento-enamel junction. 4. The intact root surface was the longest and largest in the preshedding stage. 5. The resorption process of primary teeth roots occurred mainly in the stage of preshedding and shedding stages. 6. There was a tendency of repair of resorbing root surfaces in the delayed shedding stage.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.4
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• pp.642-651
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• 2008

This study was carried out to give basic information of traumatic injuries of primary and permanent teeth which can be used for diagnosis and management of injured teeth. From January 2003 to July 2007, 570 children with 1394 teeth who came to pediatric dentistry and emergency center of Chonnam National University Hospital due to the traumatized teeth participated in this study. The following data were investigated. : age, sex, causes and places of trauma, position of injured teeth, types of injury, and treatment at the first visit. 1. Trauma prevailed at the age of 1, $6{\sim}8$, $17{\sim}18$ and the rate of males was more likely to be higher than the rate of females(1.9 : 1). 2. The main cause of injury is a fall-down injury for primary and mixed dentition, but is a traffic accident and fighting for permanent dentition, respectably. The place of injury for primary dentition is mainly home(45.3%), while street for mixed and permanent dentition. 3. The position of injured teeth according to the area in the mouth is mainly maxillary anterior teeth in both case of primary and permanent teeth and especially, the ratio of central incisors is high. 4. The periodontal tissue injury occurred the most frequently in the primary and the permanent teeth, but the ratio of hard tissue injury in the permanent teeth increased, compared with the primary teeth. 5. Among treatments at the first visit, observation without actual treatment comprised 75.6% in the primary teeth and 55.4% in the permanent teeth, respectably. The pulp necrosis occurred in 20.3% of the primary teeth and 26.6% of the permanent teeth in the case of the periodontal tissue injuries, respectably.

• The Journal of the Korean dental association
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• v.58 no.7
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• pp.398-403
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• 2020

Odontogenic anomalies can occur as a result of conjoining defects. These include fusion, gemination and concrescence. The presence of fused teeth can lead to various clinical problems, including the aplasia of permanent successor, the supernumerary teeth and delayed eruption of permanent teeth. In general, the supernumerary teeth associated with fusion is mainly found in the maxillary anterior region. This report describes rare cases of supernumerary tooth associated with fused teeth of mandibular primary lateral incisor and canine. In the first case, fused teeth was extracted. The supernumerary teeth was erupted at canine space. The second case is still being observed. Extraction of fused teeth and observation of supernumerary teeth is planned.