• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.4
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• pp.437-448
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• 2021

The purpose of this study is to analyze morphological characteristics of maxillary primary molar's root and root canal. 268 children aged 3 - 7 years (175 boys, 93 girls) who had CBCT (152 children) and 3D CT (116 children) taken in Seoul National University Dental Hospital from January 2006 to April 2020 were included. The number of roots and root canals were analyzed in 1002 teeth without any root resorption or periapical pathologies. Curvature, angulation, length of root and root canal, as well as cross-sectional shapes of the root canal were analyzed in 218 teeth. By using Mimics and 3-Matics software, volume, surface area, and volume ratio of root canal was analyzed in 48 teeth. More than half of maxillary primary molars have 3 roots and 3 root canals. The degree of symmetry of root canal type was about 0.63 (Cohen's kappa coefficient). The most frequent shape of roots and canals was linear in 1^st primary molars and curved in 2^nd primary molars. Angulation, length of root and root canals was the largest on palatal roots. Most teeth showed ovoid or round shapes at apex. The largest root canal volume, surface area, volume ratio was found in the palatal roots.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.1
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• pp.102-107
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• 2009

In clinical pediatric dentistry, we have many chances to encounter the white spot like incipient enamel lesions on the mesial surfaces of the 1st molars with direct vision, especially just after the 2nd primary molars were exfoliated. But it was thought highly desirable to assess if these lesions are properly and effectively managed yet. This study aims at surveying the prevalence of incipient lesions on the mesial surfaces of the 1st molars in children through direct observation and examining the suitability of adhesive sealing on them as a pilot trial in searching for their proper management. 1. Among the 124 mesial surfaces of the 1st molars examined, 34% were sound, 53% had incipient carious lesions and 13% had cavitated lesions. 2. In the sectional views of the specimens, 20% showed microleakage after thermo-cycling and it was thought not recommendable as a permanent method. Therefore in order to effectively fight against the incipient caries lesions in children‘s permanent teeth, it was thought proper not to rely on any one method, but to perform reinforcing oral hygiene and promotion of remineralization in combination with therapeutic sealing which is stronger in short-term sealing effect. Although therapeutic sealing has been considered as the core in minimally invasive concept to treat the white spot lesions, its long-term clinical trials have not been suggested. Continuous research is strongly required for making this approach to acquire permanent nature, especially in regards of proper pretreatment and high molecular materials deeply penetrable into enamel.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.3
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• pp.529-533
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• 2006

Supernumerary teeth are defined as an excess in the number of teeth when compared to the normal dental formula. They are more prevalent in the permanent dentition than the primary dentition. Supernumerary teeth can occur in the maxilla, mandible, or both. But the majority are found in the maxilla and most of it is found in the premaxilla region The present cases documents about the uncommon cases of supernumarary teeth on maxillarty premolar area and mandibular incisal area.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.701-704
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• 2004

In this case, we would like to discuss about the single rooted deciduous mandibular first molar. The deciduous mandibular molar of a five years old boy was shown to have a single root, bilaterally. Ordinarily, the maxilary molars have three roots and the mandibular molars have two roots. However, when the hertwig's epithelial root sheath do not invaginate properly during tooth development, root fusion can occur from the absence of root separation. Molars with fused roots not only have unfavorable crown to root ratio, but also according to many reports, have higher probability of having multiple congenitally missing teeth or dens invaginatus in the maxillary incisors, consequently requiring preventive dental treatment In addition, disorders such as ectodermal dysplasia, syndactyly, clinodactyly, bluish sclera can also be related to this condition. Root fusion is known to be of autosomal recessive inheritance. Up to date, single rooted molars have been reported several times in permanent dentitions but hardly in deciduous dentition, which is the motive for this paper.

• Journal of the korean academy of Pediatric Dentistry
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• v.42 no.1
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• pp.53-61
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• 2015

This study was conducted for the purpose of evaluating the stainless steel crowns on extracted primary molars and thus identifying frequent errors and defects. Visual assessment and micro-computed tomography (micro-CT) image analysis were performed on 97 primary molars for evaluation of the state of marginal adaptation, cement loss, secondary caries, ledge formation, attritive perforation and marginal polishing defect. The results were as follows: In the examination of object teeth by evaluation criteria, cement loss was found most frequently (98%), followed by secondary caries (42.3%), marginal polishing defect (41.2%), ledge formation (29.9%) and attritive perforation (17.5%), in this order. The cement loss at the margins showed a significant relationship with marginal gap and secondary caries: the larger the marginal gap is, the more frequent is the cement loss (p < 0.05). The average marginal gap was $0.31{\pm}0.26mm$ and showed the highest value in the maxillary 2nd primary molars. The location of the crown margin above the cementoenamel junction was found most frequently and it was found that the higher the crown margin is located, the less the marginal gap becomes (p < 0.05). In conclusion, it is thought very desirable to pay closer attention to crown margins and shapes for stainless steel crown restoration in order to minimize the marginal gaps and consequent cement loss.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.4
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• pp.591-596
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• 2009

In the case of the impacted teeth, the clinician has to consider development of tooth, site of impaction, eruption path, and cooperation of patient. Treatment options for the management of impacted teeth are separated into four categories: observation, intervention, orthodontic or surgical relocation and extraction. Autotransplantation may be defined as the transplantation of embedded, impacted or erupted teeth, from one site to another in the same individual into extraction site or surgically prepared sockets. Autotransplantation ensures preservation of natural tooth, induction of alveolar bone growth and root development, offers one of the fastest and most economically feasible means in the replacement of young patients' missing teeth. This case presents a malpositioned impacted mandibular premolar of an 11-year-old girl. It was thought that orthodontic traction was difficult because of its unfavorable impacted position. Therefore the tooth was treated by autotransplantation, we can observe good healing pattern during 12 months.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.2
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• pp.183-189
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• 2019

The purpose of this study was to investigate the changes of the position of the mental foramen according to age by using panorama of children with mixed and early permanent dentition. 180 panorama of 6 to 13-year-old boys and girls were analyzed and PiView(Infinitt, Korea) program was used. The horizontal position of the mental foramen was evaluated by the relative position of the teeth. The vertical position of the mental foramen was evaluated by the ratios between the distance from the center of the mental foramen to the inferior border of the mandible and the distance from to the alveolar crest to the inferior border of the mandible. The mental foramen was horizontally located in the anterior aspect of the second primary molar(premolar), and vertically slight below the half of mandibular body. As the age increased, it moved to the posterior and the downward and showed a significant correlation with age.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.2
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• pp.199-205
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• 2012

Although the stainless steel crowns have been recognized as the most effective and durable form of restoration for primary molars, they have been regarded by many dentists as having definite demerits such as invasive nature of procedural complexity and behavioral aspects of children. As an alternative to conventional technique of stainless steel crown restoration, the Hall technique was first introduced in 1988, which is characterized by just pushing the pre-contoured, cement filled crown form onto the abutment molar with no local anesthesia, no caries removal, no tooth preparation. According to several reports, this can slow, arrest, or even reverse the progress of caries. In addition, its atraumatic feature gives less discomfort and stress to children than conventional one, which is thought excellent especially in younger children. Also, It has been reported to be effective and acceptable to dentist, child patients and their parents. In this case study, three children with age of 4 years 5 months, 4 years 10 months, 6 years 4 months were treated with stainless steel crowns using Hall technique on first primary molar respectively. The teeth were free from pulpal, periapical pathology. After follow up of about 3 to 6 months period, the results showed clinically successful outcomes without any marked complication in pulp, tooth or soft tissue till now. But, it should be kept in mind that this technique is not proper to every child, every carious molar, or every dentist. Thorough distinction of indicated cases and continuous follow-up check is highly required. Conclusively, Hall technique might be an effective and realistic minimally invasive alternative for the carious primary molars especially in younger or disabled children, despite potential doubts on its efficacy and some definite limitations.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.1
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• pp.121-130
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• 2022

Molar-incisor malformation (MIM) is a newly reported dental anomaly with molar root deformity and incisor crown defects. MIM-affected teeth may cause severe pain with no apparent tooth caries. Since the affected molars clinically appear normal, radiographs are recommended for accurate diagnosis on the first visit. Since MIM-affected patients are in mixed dentition, timely and appropriate interventions are needed to avoid unnecessary pain and complicated clinical issues. This report was written to describe two patients who had MIM in early mixed dentition and report their 2-year follow-ups.

• 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.