• Restorative Dentistry and Endodontics
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• v.27 no.2
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• pp.196-206
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• 2002

본 연구는 근관의 치관부는 GT Rotary file을 이용하여 성형하고, 근단부는 K-Flexofile, ProFile .04, Lightspeed, HERO642 file로 성형하여 근관용 file의 근관성형력을 비교하는 것이다. 실험 표본으로는 resin simulated root canal blocks(Dentsply, Swiss)를 이용하였고 4개의 군으로 분류하여 실험을 실시하였다. 모든 resin block을 GT Rotary file(Dentsply, Swiss)을 이용하여 치관부를 형성한 후 근단부는 K-Flexofile(Dentsply, Swiss), ProFile .04 taper file(Denstply. Swiss), Lightspeed file(Lightspeed Tech., USA), HERO642 file(Micromega, France)로 ISO size #35까지 형성하였다. 성형 후 preparation time과 instrument failure를 측정하였고 최종 사용한 file을 resin block 내에 재위치시켜 working length의 변화량을 0.5mm 단위로 측정하였다. Resin debris에 의한 canal blockage를 조사하였으며, 근관 내의 인상을 채득하여 canal form을 평가하였다. 성형 전과 성형 후의 사진을 촬영하고 computer software를 이용하여 중첩시킨 후 canal aberration, canal transportation을 평가하여 다음과 같은 결과를 얻었다. 1. Preparation time, working length의 변화량, canal blockage, canal aberration, canal transportation에 있어서 Ni-Ti file이 stainless steel file에 비하여 우수하였다(p<0.05). 반면에 근관성형력에 있어서 canal form과 canal transportation을 제외하고는 세 Ni-Ti file 사이에는 유의차가 없었다(p>0.05). 2. Canal form 중 taper에 있어서 Lightspeed는 적절하지 못한 taper를 보여주었다(p<0.05). 3. Canal transportation에 있어서 Lightspeed 군과 HER0642 군이 K-Flexofile 군과 ProFile .04 군에 비해 적게 나타났고(p<0.05), 특히 만곡의 끝 부분에서는 Lightspeed 군이 가장 적게 나타났다(p<0.05). 이상과 같은 연구결과로 보아 부적절한 taper를 지니고 있던 Lightspeed fie과 HERO642 file 중 HERO642 file은 GT Rotary file과 함께 사용함으로써 적절한 taper로 형성할 수 있었으나 Lightspeed file은 효과적이지 못하였으므로 적절한 taper를 형성하기 위한 file이 치근의 중간부를 형성하기 위해 필요함이 확인되었다.

• Restorative Dentistry and Endodontics
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• v.40 no.3
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• pp.241-248
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• 2015

Variation in root canal morphology, especially in maxillary first molar presents a constant challenge for a clinician in their detection and management. This case report describes the successful root canal treatment of a three rooted right maxillary first molar presenting with three canals each in the mesiobuccal and distobuccal roots and one canal in the palatal root. The clinical detection of this morphologic aberration was made using a dental operating microscope, and the canal configuration was established after correlating and computing the clinical, radiographic and cone-beam computed tomography (CBCT) scan findings. CBCT images confirmed the configuration of the canals in the mesiobuccal and distobuccal roots to be Al-Qudah and Awawdeh type (3-2) and type (3-2-1), respectively, whereas the palatal root had a Vertucci type I canal pattern. This report reaffirms the importance of careful examination of the floor of the pulp chamber with a dental operating microscope and the use of multiangled preoperative radiographs along with advanced diagnostic aids such as CBCT in identification and successful management of aberrant canal morphologies.

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.4
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• pp.324-328
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• 2014

Aberrant anatomy of mandibular premolars is very rare in Korean, but aberration can contribute the endodontic failure as it makes difficult to remove the irritants during cleaning and shaping procedure. This case report describes the successful root canal treatment of a rare mandibular first premolar with C-shaped root canal as using a cone-beam computed tomography to understand the internal shape of root canal system and a dental operating microscope to improve the magnification and illumination.

• Restorative Dentistry and Endodontics
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• v.25 no.1
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• pp.78-84
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• 2000

The aim of this study was to compare shaping ability of nickel-titanium rotary files with different taper in simulated resin canals. The instruments used in this study were GT with .04 taper ProFile with ISO-sized tip, .04 taper ProFile with ISO-sized tip alone, and .02 taper Naviflex file and all canals were prepared by crown-down technique. A total of 30 composite images were made from pre- and post-canal scanned images using Scanjet 4C scanner and Corel photopaint 8.0 and then, prevalence of canal aberrations was measured. The amount of coronal substance the instruments removed was also calculated two-dimensionally on digitized images with the Brain C software to compare the relative enlarging efficiency. Finally, the prepared internal canal form was evaluated three-dimensionally with impression technique. The results were as follows; 1. The incidence of zipping in Naviflex group was significantly high compared to the other two groups(P<.05). 2. The amount of coronal substance the GT combined group removed was significantly larger than the other two groups(P<.05). 3. The GT combined group produced canals with good taper and flow. Under the conditionas of this study, the combined use of larger tapered nickel-titanium rotary files prepared simulated canals safely, efficiently and with good three-dimensional form.

• Journal of Korean Neurosurgical Society
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• v.38 no.1
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• pp.16-22
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• 2005

Objective : The authors characterize a syndrome of multiple neurogenic tumors in the spinal canal, which is unclassifiable by the current National Institute of Health[NIH] criteria for neurofibromatosis. Methods : We retrospectively examined cases in which two or more spinal neurogenic tumors were detected by magnetic resonance[MR] imaging and which had been pathologically confirmed. Eighteen patients were recruited between February 1986 and March 2002. According to NIH criteria, eight cases were neurofibromatosis type 1[NF1], four were type 2[NF2], and six were neither type 1 nor type 2 [Unclassifiable : UC]. The locations of lesions, clinical presentations, radiological findings, and pathological results with immunohistochemistry were reviewed. Results : In the case of NF2, three of four cases were intradural tumors. Pathological examinations revealed neurilemmomas in two of four NF2 and all of the UC cases. In the case of NF1, pathological examinations showed seven neurofibromas and one neurilemmoma. Concerning UC, the age at presentation was middle-aged to late [mean age 48.5, range 35 to 64], which contrasted with ordinary NF2, where patients tended to become symptomatic before 20years of age. The pathological examinations of UC cases revealed neurilemmoma similar to most of NF2 and the immunohistochemical study showed characteristic of NF1. Conclusion : Multiple neurogenic tumors in the spinal canal are an under-recognized disease entity. Further studies for genetic aberration in multiple spinal neurogenic tumors are needed.

• Proceedings of the KACD Conference
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• 2001.05a
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• pp.247-251
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• 2001

;A dental developmental anomaly is defined as an isolated aberration in tooth form, caused by a disturbance or abnormality which occurred during tooth development. There are numerous types of dental anomalies, and a considerable variation in the extent of the defects occurs with each type. Teeth with these anomalies pose unique challenges. Since the defects are not always apparent clinically, they can confuse diagnosticians investigating the etiology of pulpal pathosis. When endodontic treatment is required, the defects often hinder access cavity preparation and canal instrumentation. Treatment planning also becomes more challenging, since the defects can create complicated periodontal problems, and the malformed teeth can be difficult to restore, particularly those weakened by endodontic therapy. Fusion is defined as the joining of two developing tooth germs resulting in a single large tooth structure. The incidence of fusion is < 1% in the Caucasian population, and it is believed that physical force or pressure produces contact of the developing teeth. Clinically and radiographically, a fused tooth usually appears as one large crown with at least partially separated roots and root canals. There may be a vertical groove in the tooth crown delineating the originally separate crowns. Dens invaginatus is a deep surface invagination of the crown or root that is lined by enamel. Teeth in both maxillary and mandibular arches may be affected, but the permanent maxillary lateral incisor is the tooth most commonly involved. Studies have revealed an incidence ranging from 0.25% to as high as 10%. The invagination ranges from a slight pitting to an anomaly occupying most of the crown and root. The invagination frequently communicates with the oral cavity, allowing the entry of irritants and microorganism either directly into pulpal tissues or into an area that is deparated from pulpal tissues by only a thin layer of enamel and dentin. This continuous ingress of irritants and the subsequent inflammation usually lead to necrosis of the adjacent pulp tissue and then to periapical or periodontal abscesses. If the invagination extends from the crown to the periradicular tissue and has no communication with the root canal system, the pulp may remain vital. Recommended treatment of fused tooth and dens invaginatus has been reported in the endodontic literature. This case report describes the endodontic treatment of a maxillary laterl incisors having fused crown and dens invaginatus.natus.

• Restorative Dentistry and Endodontics
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• v.30 no.1
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• pp.38-48
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• 2005

The purpose of this study was to compare and evaluate the shaping ability of the three different Ni-Ti file systems used by undergraduate students. Fifty undergraduate students prepared 150 simulated curved root canals in resin blocks with three Ni-Ti file systems - $ProFile^{(R)}$ (PF), Manual $ProTaper^{(R)}$ (MPT), Rotary $ProTaper^{(R)}$ (RPT). Every student prepared 3 simulated root canals with each system respectively. After root canal preparation, the Ni-Ti files were evaluated for distortion or breakage Assessments were made according to the presence of various types of canal aberrations. The pre- and post-instrumented canal images were attained and superimposed. The instrumented root canal width were measured and calculated for the net transportation (deviation) and the centering ratio. Under the condition of this study, both $ProTaper^{(R)}$ systems allowed significantly more removal of root canal wall than the $ProFile^{(R)}$ system. In the important other aspects such as the centering ratio, there was no significant differences between the systems. Novice dental students were able to prepare curved root canals with any kinds of Ni-Ti file systems with little aberration and great conservation of tooth structure. Students want to learn effective methods and at the same time simple rotary procedures. The rotary $ProTaper^{(R)}$ systems were one of the most compatible to these students from the point of view of cutting ability The $ProFile^{(R)}$ system was also compatible in safe and gentle shaping.