• The Journal of Korea Assosiation for Disability and Oral Health
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• v.12 no.2
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• pp.72-76
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• 2016

Traumatic dental injury (TDI) is a common problem in children and adolescent. The prevalence of dental trauma among children with disability as compared to healthy children. The TDI of an immature permanent tooth can lead to the loss of pulp vitality and arrested root development. Traditionally, the treatment of choice for necrotic immature tooth is apexification, which is induction of hard tissue barrier at the apex to produce more favorable conditions for conventional root canal filling. This case report describes the treatment of a necrotic immature permanent central incisor with complicated crown fracture. The patient had multiple disabilities (cerebral palsy, congenital heart disease, developmental delay, and gait disturbance) and suffered from She was suffered from repetitive traumatic injury. Apexification and resin restoration was performed under general anesthesia, and favorable clinical results were achieved.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.2
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• pp.181-191
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• 2006

NFI-C null mice demonstrated aberrant odontoblast differentiation and thus abnormal dentin formation while other tissues/organs in the body, including ameloblasts, appear to be unaffected and normal. However little is known about the mechanism of NFI-C function in odontoblast differentiation and dentin formation. Odontoblasts are tall, highly polarized cells that are responsible for formation and maintenance of the predentin and dentin. An indication of their polarity is the acquisition of specialized intercellular junctions. As preodontoblasts differentiate into odontoblasts, they are Joined and attached at the apical end by well developed terminal webs of cytoskeletal actins, and associated tight as well as adherent njunctions. In this study, in order to investigate if disruption of the NFI-C gene interferes with formation of a specific or other structural proteins of the intercellular junctions, we examined morphological characteristic of the aberrant odontoblast in NFI-C null mice using light and electron microscope. In addition, we determined the expression of major structural proteins of intercellular junctions, ZO-1 and occludin, during the differentiation of odontoblasts using immunohitochemistry. The results were as follows : 1. In light microscopy, abnormal odontoblasts of incisors of the NFI-C null mice were round in shape, lost their polarity, and trapped in osteodentin-like mineralized tissue. Mutant molars have relatively normal crowns, but short and abnormal differentiating adontoblasts in root formation area. 2. Electron microscopy of abnormal odontoblasts revealed the dissociation of the round osteoblast-like cells, the loss of their cellular polarity, and the absence of an intercellular junctional complex known as the tight junctions. 3. A mutant incisor showed labeling for ZO-1 at the proximal and distal ends of secreting ameloblasts, while staining for ZO-1 was not observed in the abnormal odontoblasts. 4. A normal incisor showed immunoreactivity for occludin in the differentiating odontoblasts. However, staining for occludin was not observed in the abnormal odontoblasts of mutant incisor. These results suggest that NFI-C gene causes dissociation of odontoblast and thus abberant odontoblast differentiation and abnormal dentin formation by interfering with the formation of intercellular junctions.

• The korean journal of orthodontics
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• v.29 no.2 s.73
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• pp.219-237
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• 1999

This study was designed to evaluate the frequency and the severity of root resorption of the permanent teeth before orthodontic treatment by means of radiograph in the malocclusion patients. In this study the author analysed the frequency and the severity of root resorption in individual teeth, the relationships of the frequency and the severity of root resorption and age, sex, Angle's classification, overjet, overbite, and maxillary and mandibular incisor inclination, and the relationships of the frequency of root resorption and the characteristics of malocclusion and marked occlusal attrition showed in individual teeth. The results were as follows. 1. All of the persons examined showed some evidence of root resorption in one or more of the permanent teeth, $35.84\%$ of the teeth examined and more frequent in female group than male group(p<0.01). 2. On the susceptibility of the root resorption in individual teeth in this study, the author found the mandibular incisors and the maxillary incisors, in the order named, to be most susceptible in all affected teeth, but maxillary central incisors, maxillary first bicuspids, and maxillary lateral incisors, in the order named, were more susceptible to marked root resolution. 3. The more proclined maxillary Incisors the more affected root resorption in four maxillary incisors and the more proclined mandibular incisors the more affected root resorption in four mandibular incisors. 4. Overbite more affected root resorption than overjet, and the higher tender to openbite the more frequent was root resorption. 5. On the characteristics of malocclusion showed in individual teeth, the openbite teeth combined with crossbite, were most frequent in root resolution.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.3
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• pp.381-386
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• 2010

As the vertical fracture occurs at the various locations following the long axis of a root, treatment method of crown-root fractured anterior teeth is decided according to the depth. If the fracture line is close to the crown, gingivectomy, orthodontic - forced eruption or surgical extrusion of apical fragment could be done. If the line is over 1/3 length of the root, the prognosis is poor and extraction is usually undertaken. However, extraction of maxillary incisor at growing children causes many complications such as esthetic, phonetic problem and alveolar bone resorption. Therefore, preservation of tooth is the highest priority. Recently, intentional replantation with composite resin could be considered as alternative treatment of crown-root fractured anterior tooth. This report presents a patient in mixed dentition with deep vertical crown-root fracture of the maxillary permanent central incisors by trauma. Intentional replantation of the fractured teeth was performed using composite resin. After 2 years, specific clinical symptom has not been found and the patient was satisfied of esthetic result. This method suggests the new technique to preserve a tooth as an alternative to extraction, although it is technically sensitive and the reports of long-term prognosis is insufficient.

• The korean journal of orthodontics
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• v.28 no.2 s.67
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• pp.297-310
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• 1998

The purpose of this study was to investigate the initial tissue change, to repair on the teeth & surrounding tissue under the intrusive orthodontic forces by use of elastic chain, through the microscopic findings. For this study, three young adult mongrel dogs were used, and were divied into three group : the control group was deliveried only casting crown and the experimental group 1 was equipped with energy chain during 1 week and experimental 2 group was deliveried using energy chain during 1 week and 3 weeks observation. All experimental groups and control groups were sacrificed to make the samples for microscopic findings on premolar teeth. All samples were examed and compared the histologic changes through the microscopic with H-E stain. The obtained results were as follows. 1. In hematoxylin-eosin stain of the control group, the periodontal ligament was constant width from apical third to cervical third of the root, and the periodontal fiber arrangement was horizontal or oblique in cervical third, oblique in middle and apical third of the root. 2. In Masson Trichrome stain of the control group, osteoblast and osteoclast appeared in cervical third of root, and bone resorption and new bone formation was observed in middle and apical third of the root. 3. In experimental 1, osteoclasts were increased highly, and hyperemia of blood vessels and new bone formation and bone resorption by reversal line in apical third of the root were seen. PDL width was increased apprarently from crest to apex of the root and more in apical third. 4. In experimental 2, osteoclasts and hyperemia of blood vessels were more increased than control material in apical third of the root. PDL width was increased more than control group in root apex, and was seen less than experimental 1. PDL arrangement was similar to experimental 1 and was mixed only in root apex. Therefore, in premolar intrusion of the young adult dog, there were increased osteoclast, hyperemia and dilation of blood vessel, resorption of alveolar bone and cementum and different arrangement of PDL in initial tissue change. There was not observed complete repair after remove intrusive force.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.2
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• pp.174-180
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• 2012

In case of an immature tooth with necrotic pulp, regeneration of pulp tissue into a canal would be the ideal outcome. It may be capable of promoting the continuation of normal root development. Platelet-rich fibrin has been suggested as a potentially ideal scaffold for regenerative endodontic treatment. Immature permanent teeth of young children were diagnosed with pulp necrosis and apical abscess as the result of clinical and radiographic examination. After removal of necrotic pulp, canal was irrigated with 5.25% NaOCl and dried with paper point. A triple antibiotic mixture was placed in canal space in 3 weeks. After removal of the antibiotic mixture, the platelet-rich fibrin was injected into the canal space with MTA placed directly over the platelet-rich fibrin clot. The coronal region was restored by composite resin. On the basis of short-term results of the present 3 cases, regeneration of vital tissues appears to be possible in a tooth with necrotic pulp and a periapical lesion. Also, platelet-rich fibrin proves to be potentially an ideal scaffold for this procedure. Therefore, long-term clinical observation and examination about this treatment using platelet-rich fibrin in immature permanent teeth of young children are considered to be necessary.

• The korean journal of orthodontics
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• v.35 no.2 s.109
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• pp.106-115
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• 2005

This study was aimed to investigate the effects of indomethancin on physiologic root resorption and to examine the dental pulp and tissue changes around the resorbing teeth 13-14 week old six mongrel dogs were divided into 3 groups, two experimental groups administered indomethacin 2mg/kg/day and 8mg/kg/day orally two times a day for 14 days respectively. and control group administered a placebo The deciduous incisors showing root resorption were selected. fixed for 24 hrs in $10\%$ formalin solution. demineralized in $10\%$ EDTA solution. Invested in paraffin and sectioned in $5{\mu}m$ thick sections. The preparations were stained with H&E staining and Masson's trichrome staining and examined under the light microscope Observation revealed that deciduous root resorbing tissue resembles inflammatory tissue and accompanies bore remodelling. The dental pulp was formal except the area near root resorption. well organized columnar odontoblasts layer under the predentin, anud the odontoblasts near root resorption were cuboidal or flat cells in the disrupted layer under the predentin. Indomethacin administered group showed a partial decrease in the number of odontoclasts and nucleus But there was no sign of pulp change by indomethacin. These results suggest that indomethacin inhibits recruitment of odontoclasts partially and that of osteoclasts more. and so when it is administered for long periods deciduous root resorption can be delayed and eruption of the successor can be delayed for a short period.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.1-6
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• 2000

Dentinogenesis imperfecta is an inherited disorder of dentin formation, usually exhibiting an autosomal dominant mode of transmission. Type I dentinogenesis imperfecta occurs in patients afflicted with osteogenesis imperfecta. Type II dentinogenesis imperfecta is not associated with osteogenesis imperfecta. Type III dentinogenesis imperfecta (Brandywine type) occurs in a racial isolate area in the state of Maryland. In all three types, teeth of both dentitions are affected with variable clinical appearances. The teeth are opalescent with the color ranging from bluish-gray to brown to yellowish. The dentin is abnormally soft, providing inadequate functional support to the overlying enamel. Although the enamel is normal, it fractures or chips away easily, exposing the occlusal and incisal dentin. The exposed soft dentin often undergoes rapid and severe functional attrition. The teeth exhibit bulb-shaped crowns with constricted cementoenamel junctions and thin roots. The teeth will exhibit varying stages of obliteration of the coronal and root pulpal chambers. The cementum, periodontal ligament and supporting alveolar bone appear normal. The enamel is normal. The mantle dentin remains nearly normal, whereas the remaining dentin is severely dysplastic. The dentinal tubules are disoriented, irregular, widely spaced, and usually larger than normal.

• 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.

• The korean journal of orthodontics
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• v.29 no.5 s.76
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• pp.551-562
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• 1999

This study was undertaken to investigate the relation between orthodontic force magnitude and the amount of tooth movement. And more light force application for reducing root resorption Twenty-four rats were divided into three experimental groups(A, B, C) based on force magnitude and application method. Springs of 50g force were applied to A group, springs of 100g force were applied to B group and springs of 25g force were applied to C group initially, and after 4 days springs of C group were changed to springs of 50g force. Two kinds of $sentally^{(R)}$(GAC U.S.A.) closed coil spring, 50g and 100g, were used. And we made 25g springs by heat treatment process of 50g springs. Each spring was inserted between the maxillary central incisor and the maxillary left first molar. Amounts of tooth movement were measured everyday by digital caliper($Digimatic^{(R)}$, Mitutoyo, Japan) under inhalation anesthesia for 15 days. After 15 days, all rats were sacrificed and histological samples were obtained with Hematoxyline-Eosin stain and Masson's trichrome stain. Following conclusion were made; 1. Group B showed the mean cumulative tooth movement of $2.19{\pm}0.41mm$ at 15th day, which was greatest among three groups, followed by group C($2.06{\pm}0.10mm$), group A($1.90{\pm}0.49mm$) respectively. however, there was no statistically difference among three groups. 2. All groups showed general tooth movement pattern and A, B, C group finished lag phase at 9th, 8th, 7th day, but there was no statistical significance. 3. Group A,B,C showed root resorption and especially group B showed the most severe root resorption and group C showed milder root resorption than other groups. According to the above results, large initial force with the development of a flirty widespread hyalinized zone may cause severe root resorption, so initial force should be applied lightly to reduce hyalinized area and eventually root resorption and then increased force will induce efficient tooth movement.