• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.1
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• pp.123-130
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• 2018

In the root fracture, pulp necrosis tends to involve only the coronal fragment, while the pulp in the apical fragment remains vital. The prognosis of endodontic treatment of the apical fragment is poor due to the possibility of overfilling of the space between the fragments and difficulty in removing necrotic tissue. In the present cases, endodontic treatment of the apical fragment of root fracture was performed. However, in reendodontic treatment, resistance was felt at the fracture site and access to the root canal in the apical fragment was difficult. Therefore, the calcium hydroxide was periodically exchanged only in the coronal fragment without further treatment in the apical fragment and the canal of the coronal fragment was finally filled with Gutta-percha. Regular observation revealed no radiologic complications in the apical fragment. In some cases, we can observe good healing pattern such as absorption of calcium hydroxide and pulp canal obliteration of apical fragment in the long term.

• The Journal of the Korean dental association
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• v.54 no.5
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• pp.365-373
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• 2016

Purpose: Cemental tear is a specific type of root surface fracture characterized by a complete separation of a cemental fragment along the cementodentinal junction or a partial split within the cementum along an incremental line. It is suggested to be a factor for periodontal or periapical tissue destruction. The aim of this study is to present a diagnosis and treatment of cemental tear associated with periapical lesion with root canal treatment and regenerative periodontal surgery. Treatments: A 60-year-old male who had a history of sports trauma on the mandibular right central incisor about 10 years ago presented with apical cemental tear. Clinical examination showed a slightly dark yellowish discoloration and sinus tract that was located on the apical labial mucosa. The mobility and percussion were also assessed on the diseased tooth and recorded as $Miller^{\circ}{\phi}s$ Class II and tenderness to percussion. The probing depth was within the normal limit (<3 mm). Radiographic examination revealed a radiolucent lesion at the apical area and extended to distal aspect of the tooth along the fragment of cemental tear. After root canal treatment, periapical surgery was performed. The bony defect was exposed and then the detached root fragment was removed. Apical root resection and retrograde filling with Mineral Trioxide Aggregate (MTA) were accomplished and the bony defect was filled with deproteinized bovine bone mineral (DBBM) and covered with biodegradable collagen membrane. Results: After 9-month follow-up, healing of the mandibular right central incisor was uneventful and no swelling, purulence or pain was revealed in the associated area. Probing pocket depth was favorably stable, and the tooth mobility was decreased to the Miller's Class I. Conclusions: Apical cemental tear associated periapical lesion could be successfully treated with removal of the detached cementum in combination with apical surgery and GTR procedure.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.2
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• pp.344-350
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• 2000

Incidence of crown-root fracture due to traumatic injury, have been reported 3% in the permanent dentiton, 2% in the deciduous dentition. There are two treatment methods for crown-root fractured teeth with pulp exposure, when the fracture line was located under the alveolar crest. One way is the extrusion by orthodontic force the other way is intra-alveolar transplantation which occlusally repositioning of apical fragment in the alveolar socket. Since intra-alveolar transplantation has introduced in 1970s, it was practiced as alternative to orthodontic extrusion. As the result, this method may thoughted that had a good prognosis. As a result of trauma, completely crown-root fracture was occured in the maxillary right central incisor in this case. We couldn't reposition the deepest fracture line above the alveolar crest by the conventional surgical extrusion, because apical fragment was too short. Thus, after extraction of apical fragment, we repositioned it to the socket following demineralized freezed dried bone graft, which possible to support the apical fragment. At the 15-month recall examination, the root still showed normal mobility and there was not observed any in flammatory or replacement root resorption in the periapical radiograph.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.1
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• pp.156-161
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• 2007

Pediatric dentists are frequently encountered with fractured root fragments of primary teeth caused either by the traumatic injuries or by the accidental fractures during the procedure of tooth extractions. In these situations, we often hesitate which method to choose, extract or retain it. In general, it is recommended to retain apical fragments, as the attempts to extract the apical fragments might harm the developing permanent tooth germ. This study was designed to ensure the validity of intentional retention of the root fragments of primary teeth in the situations described above. 6 children with intentionally root fragments who experienced root fracture in primary anterior teeth were available Periodic radiographic assessment was performed at 3 months interval for $7{\sim}37$ months. The results of this study showed that apical fragments had been resorbed through physiologic process in 5 patients. Apical fragment had been gingival emergence along with the erupting permanent tooth in 1 patient. There were no evidence of interference with eruption of permanent successors. In summary we have been ensured the validity of intentionally retention of the root fragments of primary teeth. Children with being remained apical root fragment should be recalled regularly for assessment and parents should be thoroughly informed about the situation with special emphasis on the necessity of periodic check-up.

• The Journal of the Korean dental association
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• v.54 no.8
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• pp.640-650
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• 2016

Nickel-Titanium (NiTi) rotary instruments have brought a big step toward "efficient" practice of endodontic procedure. The rotary files help clinicians to reduce their working time and also increase the clinical success rate with minimal procedural errors. However, NiTi instruments still have a few drawbacks including unpredictable fatigue fracture. Clinicians may reduce the potential risk of instruments fracture by following some clinical guidelines for rotary instruments. In some clinical cases of instruments fracture, we may try to remove the instruments' fragments or bypass the fragment to reach the apical canal. In some limited cases, the fractured instruments' fragments would not jeopardize the clinical prognosis of root canal treatment. Nevertheless, it is impossible to be overemphasized that the prevention of file fracture is much easier than the removal of fracture fragment. Clinicians need to understand the fracture mechanisms and, in clinic, need to discard the used instruments timely.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.2
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• pp.288-292
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• 2009

A crown-root fracture is defined as a fracture involving enamel, dentin, and cementum. The fractures may be grouped according to pulpal involvement into uncomplicated and complicated. Generally a vertically crown-root fractured tooth must be extracted. However, it should be mentioned that the cases have been reported where bonding of the coronal fragment has led to consolidation of the intraalveolar part of the fracture. Definitive conservative therapy comprises one of four treatment alternatives; fragment removal only, fragment removal with gingivectomy, orthodontic extrusion of apical fragment, and surgical extrusion of apical fragment. The choice is primarily determined by the exact information on the site and the type of fracture, but the cost and the complexity of treatment can also be decisional factors. On the other hand, intentional replantation of the teeth with vertical root facture reconstructed with resin bonding has emerged as a new promising method in recent years. This case presents an intentional replantation of the crown-root fractured maxillary central incisor reconstructed with resin bonding. However, an obvious increase of radiolucency was observed after 4 months and the tooth was re-fractured after 16 months.

• The Journal of the Korean dental association
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• v.52 no.2
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• pp.60-68
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• 2014

Nickel-Titanium(NiTi) rotary instruments have brought a big step toward "efficient" practice of endodontic procedure. The rotary files help clinicians to reduce their working time and also increase the clinical success rate with minimal procedural errors by stainless steel instruments. In spite of these advantages, NiTi instruments still have a few drawbacks including unpredictable fatigue fracture. Clinicians may reduce the potential risk of instruments fracture by following some clinical guidelines for rotary instruments. In some clinical cases of instruments fracture, we may try to remove the instruments' fragments or bypass the fragment to reach the apical canal. In some limited cases, the fractured instruments' fragments would not jeopardize the clinical prognosis of root canal treatment. However, it is impossible to be overemphasized that the fragment removal is more difficult than the prevention of fracture. Clinicians need to understand the fracture mechanisms and, in clinic, need to discard the used instruments timely.

• Research in Plant Disease
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• v.21 no.1
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• pp.1-5
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• 2015

A PCR method has been developed for the pathovar-specific detection of Pseudomonas syringae pv. tagetis, which is the causal agent of bacterial leaf spots and apical chlorosis of several species within the Compositae family. One primer set, PSTF and PSTR, was designed using a genomic locus derived from an amplified fragment length polymorphism (AFLP) fragment produced a 554-bp amplicon from 4 isolates of P. syringae pv. tagetis. In DNA dot-blot analysis with the PCR product as probe, a positive signal was identified in only 4 isolates of P. syringae pv. tagetis. These results suggest that this PCR-based assay will be a useful method for the detection and identification of P. syringae pv. tagetis.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.2
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• pp.200-206
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• 2016

Root fracture is defined as a fracture involving the dentin, cementum, and pulp. Most fractures occur in the maxillary anterior teeth between the ages of 11 and 20 years old. The treatment for root fracture in permanent teeth involves the reduction and fixation of the displaced coronal segment. When signs of pulp necrosis or inflammatory root resorption are present, root canal therapy should be performed. Since most apical fragments maintain pulp vitality, root canal therapy is typically limited to coronal fragments. However, it's too difficult to achieve a proper apical stop on coronal fragment. Intentional replantation involves performing root apex treatment outside the mouth after intentional extraction of the tooth in a controlled environment and then replanting it. The objective is 'perfect' root canal therapy. Intentional replantation may be used in cases of failed typical root canal therapy, problematic endodontic retreatment due to the existing restoration or a calcified root canal, and when apical surgery is contraindicated because of a lack of reasonable approaches. In this case, intentional replantation was carried out to treat a horizontal root fracture in a maxillary central incisor with a calcified root canal due to previous trauma. We achieved a clinically and functionally satisfactory result.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.3
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• pp.571-577
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• 2008

Root fracture of primary teeth is relatively uncommon because the more pliable alveolar bone allows displacement of the tooth. Root fracture of primary teeth is occupied $2{\sim}7%$ in trauma pattern of primary teeth. A horizontal root fracture is classified based on the location of the fracture in relation to the root tip : the apical third, middle third, or cervical third of the root. The prognosis worsens the further cervically the fracture has occurrer. Root fracture of primary teeth should be treated by splinting the incisor to the adjacent normal teeth with a resin-wire splint for $8{\sim}12$ weeks. However, if a portion of the root is abscessed or extremely mobile, it can be extracted, and the remaining root fragment will resorb normally. For coronal third fracture in primary teeth, the coronal third is extracted, leaving the apical portion of the root to resorb normally. These root fracture cases of primary teeth were treated by resin-wire splinting despite extremely mobile coronal fragment. Even though they seems like healing well, They need to be monitored regularly until their successors erupt.