• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.1
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• pp.115-121
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• 2021

Dilacerations generally involve central incisors; most often maxillary incisors rather than their mandibular counterparts. The clinical features of dilaceration include non-eruption of the responsible tooth or prolonged retention of the deciduous predecessor tooth. In Case 1, the tooth showed a dilaceration at the boundary between the crown and the root, more laterally rather than labiolingually. In Case 2, the dilacerated tooth showed a crown dilaceration with a relatively normal orientation of the dental root. In both cases, no significant space losses for eruption were observed. Moreover, it seems that unlike the maxilla with the palate, the mandibular anterior teeth are limited to show severe displacement. From these cases, it is suggested that if a mandibular permanent incisor shows a crown dilaceration or lateral dilaceration at the boundary between the crown and the root, there is a relatively high probability of spontaneous eruption of the dilacerated tooth.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.12-15
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• 2001

Dilaceration is a tooth abnormaly occuring in the histo-morphodifferention stage resulting from disturbance between the uncalcified and already calcified portion that affects both the crown and root. The involved tooth is usually the maxillary central incisor and it also shows high prevalence of impaction. The cause of dilaceration can be either from the trauma of the primary tooth, ectopic development of the tooth germ or from cysts. And it is also found in some cases of Otodental syndrome, Hurler syndrome, Cleidocranial dysostosis. The purpose of this study is to show that periapical lesions caused by dental caries can be another factor in causing dilaceration.

• Restorative Dentistry and Endodontics
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• v.28 no.2
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• pp.146-155
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• 2003

여러 가지 장점으로 인해 Ni-Ti 전동 파일을 근관성형에 사용하는 빈도가 점차 증가되는 추세이지만, 초심자를 대상으로 한 연구는 부족한 실정이다. 이에 본 연구에서는 초심자에서 Ni-Ti 전동 파일을 사용할 때 근관 형성의 효용성을 평가하고, 어떤 방법이 초심자에게 적절한지를 알아보고자 하였다. 근관형태가 재현된 레진 블록을 이용하여 12명의 초심자와 4명의 숙련자가 근관 형성을 시행하였다. 각 술자는 ProFile, ProTaper, Hybrid (ProFile＋ProTaper)를 이용하여 각각의 레진 블록을 세 개씩 근관형성하고, 각 파일 별의 근관 형성 시간을 기록하였다. 근관 형성 전과 후의 digital 이미지를 중첩하여 치근단으로부터 1, 2, 3, 4, 5, 6, 7mm level에서 근관단면의 총길이 변화량, 만곡 외측의 길이 변화량, 만곡 내측의 길이 변화량, 중심이동량, 중심이동율과 치근단에서의 apical transportation을 구하고, 초심자와 숙련자 사이의 차이를 비교 평가하였다. 실험결과 ProFile군의 1, 3, 5, 6, 7mm level과 ProTaper군의 6mm level, Hybrid군의 3mm level에서 초심자의 근관단면의 총길이 변화량이 숙련자보다 많았다. 모든 군에서 치근단으로부터 4, 5, 6, 7mm level에서는 근관 중심이 만곡내측으로 이동하였고, 1 2, 3mm level 에서는 만곡외측으로 이동하였으나, 숙련자가 시행한 Hybrid군의 3mm level과 비숙련자가 시행한 ProTaper 군의 3mm level에서는 만곡내측으로 이동하였다. 모든 군의 3mm level과 ProFile 군의 5mm level에서 초심자의 중심이동율이 숙련자에 비해 컸으며, 초심자가 ProTaper를 사용시 더 큰 apical trans portation을 보였고, 모든 군에서 초심자가 근관형성시 더 많은 시간이 걸렸다. ProFile과 ProTaper를 이용한 Hybrid technique이 초심자에게 추천되며, 초심자들도 충분히 교육받는다면 만곡된 근관의 근관형성에 있어서 Ni-Ti rotary file의 이용이 가능하리라고 사료된다.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.637-642
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• 2003

Morphology of primary root divergency and curvature determines the pattern of root resorption and periapical lesion, and affects successful root canal treatment. With the purpose of analysing the morphology of primary mandibular second molar roots and canals, the frequency, angle, radius, and start of curvature of the canal were measured. Fifty clinical radiographs were taken from $3{\sim}6$ years old children, followed by digitizing after scanning and analyzing by Scion image Beta 4.02TM(Scion Co. USA). The angle of curvature was determined by Schneider's method and the radius of curvature was determined by Schaefer's method. The results were as follows: 1. The angle of curvatures were $17.3^{\circ}{\pm}5.0$ (mesial), and $27.9^{\circ}{\pm}6.0$ (distal). Distal curvature was significantly larger than mesial.(p<0.05) 2. The radius of curvatures were $8.7mm{\pm}2.5$ (mesial), and $5.8\;mm{\pm}1.5$ (distal). Mesial curvature was significantly larger than distal.(p<0.05) 3. The start of curvatures were $4.1mm{\pm}0.6$ (mesial), and $4.2mm{\pm}0.6$ (distal). There were no difference between two groups. (P<0.05)

• The korean journal of orthodontics
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• v.37 no.2 s.121
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• pp.159-163
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• 2007

Impaction with a severely dilacerated root is seldom reported, especially in the maxillary incisor. It is probably because of the high clinical difficulty associated with bringing the dilacerated tooth into proper position, and the high chance of failure due to ankylosis, external root resolution, and root exposure after orthodontic traction. Even the successful cases may need periodontal surgery to improve the unesthetic gingival shape. However, it has previously been reported that an impacted maxillary central incisor was successfully treated by proper crown exposure and orthodontic traction. This article presents a case of an invertedly impacted maxillary right central incisor with a developing dilacerated root, which was aligned into proper position after orthodontic traction composed of two stages of a closed eruption technique.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.3
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• pp.437-443
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• 2005

Dilaceration is most common in maxillary central incisor. Impaction by dilacerated tooth cause orthodontic problem such as tilting of adjacent tooth, midline deviation. Dilaceration is caused by trauma, cyst, other origin and tooth shape, degree of root curvature, location in the alveolar bone, ability of spontaneous eruption should be considered whether treat or not. Labially and lingually dilacerated tooth is difficult to spontaneous eruption. Thus, Prosthetic treatment alternative with extraction, auto transplantation, orthodontic traction with surgical exposure is included within the treatment alternative. These cases are about impacted central incisor with dilacerated root. We use closed eruption technique and guide impacted tooth into normal position by orthodontic traction.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.2
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• pp.166-173
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• 2012

Dilaceration is a developmental disturbance in shape of teeth. It refers to an angulation, or a sharp bend or curve, in the root or crown of a formed tooth. Dilacerations are estimated to occur in 3% of all permanent dentitions. However, the etiology of dilaceration is not yet fully understood. Traumatic injury to the deciduous predecessors and ectopic development of the tooth germ are the two commonly cited causes of this anomaly. The involved tooth is usually the maxillary central incisor and it also shows high prevalence of impaction. At first, We tried to do surgical exposure with orthodontic traction but to no avail. After then surgical repositioning of the dilacerated tooth was performed. Finally, Satisfactory results were obtained at the end of treatment, with improvement in dental esthetics and functional aspects.

• The Journal of the Korean dental association
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• v.26 no.12 s.235
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• pp.1131-1135
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• 1988

• The Journal of the Korean dental association
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• v.31 no.4 s.287
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• pp.295-304
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• 1993

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.1
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• pp.82-87
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• 2011

The pulp infection of primary tooth is often caused by dental caries or trauma. But, if it is not managed properly, it can be produce the periapical lesion. The periapical lesion can cause some complications such as enamel hypoplasia, displacement, root dilaceration and impaction. Treatment options of displaced permanent successor are clinical and radiological follow-up after extraction of primary teeth, surgical opening, orthodontic traction, transplantation and extraction. In these cases, the premolars with abnormal eruption path caused by periapical lesion of the primary tooth have shown successful spontaneous eruption just as a result of extraction of infected primary tooth and space maintenance.