• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1999년도 정기총회 및 춘계 공동 학술발표회
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• pp.6-7
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• 1999

• Restorative Dentistry and Endodontics
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• 제49권3호
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• pp.26.1-26.14
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• 2024

Objectives: This study aimed to investigate the frequency and type of endodontic procedural errors in cases indicated for retreatment through cone-beam computed tomography (CBCT) analysis. Materials and Methods: The sample consisted of 96 CBCT scans, encompassing 122 permanent teeth with fully formed roots. Errors included perforation, instrument fracture, canal transportation, missed canals, and inadequate apical limit of filling. Additionally, potential risk factors were analyzed and subjected to statistical modeling. Results: The most frequent procedural error observed was the inadequate apical limit of filling, followed by canal transportation, perforation, missed canal, and instrument fracture. Statistically significant associations were identified between various procedural errors and specific factors. These include canal transportation and root canal wall, with the buccal wall being the most commonly affected; missed canal and tooth type, particularly the palatine and second mesiobuccal canal canals; inadequate apical limit of filling and root curvature, showing a higher deviation to the mesial direction in severely curved canals; inadequate apical limit of filling and the presence of calcifications, with underfilling being the most frequent; canal transportation and periapical lesion, notably with deviation to the buccal direction; and the direction of perforation and periapical lesion, most frequently occurring to buccal direction. Conclusions: CBCT emerges as a valuable tool in identifying procedural errors and associated factors, crucial for their prevention and management.

• Restorative Dentistry and Endodontics
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• 제23권1호
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• pp.257-268
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• 1998

During cleaning and shaping of narrow and curved canals, it is very difficult or nearly impossible to maintain the original canal shape. Procedural accidents such as, ledge, zipping, perforation, and instrument breakage are frequently occurred and even may lead to failure of endodontic therapy. To prevent these kinds of accidents, various instrumentation techniques and materials have been introduced. Recently some nickel titanium (NiTi) files are introduced and it is reported that These NiTi files created rounder preparations with less transportation than conventional instruments in curved canals. This study compared the change of the canal curvature and procedural accidents after instrumentation produced by stainless steel K-flexo file, and NiTi rotary files (Profile 29 and Quantec 2000). Thirty narrow and curved canals (25-45 degree) of extracted human molars were randomly divided into three groups. In group 1, canals were instrumented using a step-back and watch-winding/pull motion with K-flexo files. In group 2, canals were prepared with Profile 29. Group 3, canals were prepared with Quantec 2000 files. Before and after preparation of canals, periapical radiographs were taken and scanned. The change of canal curvature were measured using Photoshop 4.0 program and the incidence of procedural accidents were also evaluated. The results were as follows: 1. All group showed some loss of canal curvature after instrumentation. 2. Average loss of canal curvature was $6.70{\pm}5.31$ degree for group 1, $3.80{\pm}2.57$ degree for group 2, and $5.40{\pm}4.83$ degree for group 3. All group There was significant change in curvature between before and after instrumentation (p<0.05). But there was no statistical difference amoung 3 groups. 3. In group I, there were no procedural accidents, such as ledging, perforation, or instrument fracture. In group 2, two cases of ledge and one case of instrument fracture were produced Goup 3, each one case of ledge, perforation and instrument fracture were occurred. Whthin the limits of above results, It seems that NiTi rotary instrumentation is not All Mighty and if we use uncarefully, it is more dangerous to produce some procedural accidents than conventional hand files. But more studies should be taken to evaluate the exact effects of NiTi rotary instrumentations.

• Restorative Dentistry and Endodontics
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• 제45권2호
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• pp.22.1-22.10
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• 2020

Objectives: This study investigated the influence of glide path size and operating kinetics on the time to reach the working length and the fracture resistance of Twisted File (TF) and Endostar E3 files. Materials and Methods: A total of 120 mandibular single-rooted premolars were selected. Two methods of kinetic motion (TF adaptive and continuous rotary motion) and file systems (TF and Endostar E3) were employed. The files were used in root canals prepared to apical glide path sizes of 15, 20, and 25. The time taken to reach the working length and the number of canals used before the instrument deformed or fractured were noted. Fractured instruments were examined with scanning electron microscopy. Results: The TF system took significantly more time to reach the working length than the Endostar E3 system. Both systems required significantly more time to reach the working length at the size 15 glide path than at sizes 20 and 25. A greater number of TFs than Endostar E3 files exhibited deformation, and a higher incidence of instrument deformation was observed in adaptive than in continuous rotary motion; more deformation was also observed with the size 15 glide path. One TF was fractured while undergoing adaptive motion. Conclusions: No significant difference was observed between continuous rotary and adaptive motion. The TF system and adaptive motion were associated with a higher incidence of deformation and fracture. Apical glide path sizes of 20 and 25 required significantly less time to reach the working length than size 15.

• 대한두개안면성형외과학회지
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• 제20권5호
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• pp.284-288
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• 2019

Background: Closed reduction of nasal fracture with various instrument is performed to treat nasal fracture. Depending on the type of nasal fracture and the situation in which it is being operated, the surgeon will determine the surgical tool. The objective of this study was to investigate whether a periosteal elevator (PE) was a proper device to perform closed reduction for patients with simple nasal fractures. Methods: From March 2018 to December 2018, 50 cases of simple nasal bone fracture underwent closed reduction performed by a single surgeon. These patients were divided into two groups randomly: nasal bone reduction was performed using only PE (freer) and nasal bone reduction was performed using Walsham, Asch forcep, and Boies elevator (non-freer, non-PE). Results: The paranasal sinus computed tomography was performed on patients before and after operation to carry out an accurate measurement of reduction distance at the same level. According to the results, the interaction between instruments and fracture types had a significant influence on reduction distance (p = 0.021). To be specific, reduction distance was significantly (p= 0.004) increased by 2.157 mm when PE was used to treat patients with partial displacement compared to that when non-PEs were used. Conclusion: Closed reduction using PE and other elevator is generally an effective treatment for nasal fracture. In partial-displacement type of simple nasal fracture, closed reduction using PE can have considerable success in comparison with using classic instruments.

• 대한정형외과스포츠의학회지
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• 제11권1호
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• pp.62-65
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• 2012

소아 전방 십자인대 견열 골절은 비교적 드물게 발생하며, 주로 청소년기에 발생하고 경쟁 경기 중의 발생빈도가 증가하고 있다. 수술 후 합병증을 감소시키기 위해 최근에는 관절경적 수술방법이 많이 사용되고 있다. 나사못, K-강선, 봉합 나사못 등이 사용되고 있으며, 유관 나사못 고정술은 수술 술기가 가장 간단하나 단점으로 성장판 손상의 가능성이 있다. 저자들은 8세 여아의 전방 십자인대 견열 골절에서 관절경을 이용한 유관 나사못 고정술로 좋은 결과를 얻었기에 문헌 고찰과 함께 보고하는 바이다.

• Restorative Dentistry and Endodontics
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• 제8권1호
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• pp.53-59
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• 1982

An in vitro study was performed in order to evaluate the restoring methods in the endodontically treated molar teeth. 68 extracted teeth were divided into 4 groups according to the restoring techniques. The teeth of first group were restored by amalgam. Those of second group were restored by the stainless steel post and amalgam. The teeth of the third group were restored by the amalgam with crown. The teeth of the fourth group were restored by the stainless steel post and amalgam core with crown. All the specimens were tested and measured for the fracture load by means of the Instron (UTM-111-500 Toyo Baldwin Co., LTD. Japan) and the Pressure Instrument (Yonsei University, Department of Metal Engineering.) The results were as follows; 1. There were no statistical differences in the fracture loads between the amalgam restoration and post-amalgam core restorative techniques. 2. The techniques of amalgam core with crown showed lower fracture loads those of post and amalgam core with crown. 3. In the crowned teeth, they presented higher fracture loads than those without crown.

• 한국주조공학회지
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• 제32권6호
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• pp.305-312
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• 2012

As the industrial civilization develops, humankind can expect to receive the convenience and richness. But the various by-product which it leaves as the pollution threatens the natural environment. Especially, noise and vibration of these pollutions are causative of the mental instability and hard of hearing. In addition, they cause the performance degradation of the precision instrument and the early rising fatigue fracture of parts of precision instrument from the industry side. So recently interest in the damping technology and damping alloy is increasing. Therefore, in order to grasp the advanced technology of the damping alloy, we analyzed global techniques and patents information in this paper.

• 대한치과교정학회지
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• 제26권5호
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• pp.613-622
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• 1996

도재브라켓의 제거방법에 따라 법랑질표면에 미치는 영향을 비교 평가하기 위하여 80개의 발거된 소구치를 대상으로 통법에 의해 도재브라켓을 부착시키고 일 주일후 각각 40개의 기계적 방법에 의한 제거군과 전기열전도 방법에 의한 제거군으로 구분하여 도재브라켓의 제거를 유도한 후, 그 탈락양상 및 도재브라켓과 법랑질 표면의 주사선사현미경 관찰을 시행하였으며, 전기열전도 방법에 의한 제거군을 다시 각가 10개씩 고속 tungsten carbide but에 의한 연마군, 저속 sof-lex disc에 의한 연마군, 고속 resin polishing bur에 의한 연마군, 그리고 초음파 치속제거기에 의한 연마군으로 분류하여 잔여레진의 연마를 시행한 후, 잔여레진의 평가에 의해 다음과 같은 결론을 얻었다. 1) 결찰와이어 절단용 겸자를 이용한 도재브라켓의 기계적 제거시, 0.69의 평균 잔여레진 부착지수를 보임으로써 법랑질과 레진 경계부에서 파절이 가장 빈발한 양상을 보였다. 2) 전기열전도 방법을 이용한 도재브라켓의 제거시 2.19의 평균 잔여레진 부착지수를 보임으로써 브라켓과 레진 경계부에서의 파절이 가장 빈발한 양상을 보였다. 3) 기계식 방법으로 도재브라켓의 제거시, 법랑질표면의 주사현미경 관찰소견은 실험군의 $7.5\%$에서 법랑질표면의 탈락과 패임 등의 손상을 보였다. 4) 잔여레진의 제거의 고속 resin polishing bur사용군에서 가장 적은 잔여레진막을 보였다.

• Restorative Dentistry and Endodontics
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• 제46권2호
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• pp.28.1-28.10
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• 2021

Objectives: This study evaluated the effect of repeated uses and autoclaving in the instrumented area, fracture resistance, and time of instrumentation of thermally treated nickel-titanium reciprocating systems. Materials and Methods: Two hundred simulated canals were instrumented using Reciproc Blue and WaveOne Gold. Each file was used up to 10 times or until fracture. The instrumented area was measured in pre- and post-operative images, using ImageJ software. Kaplan-Meier survival analysis evaluated the number of uses of instruments before fracture. Instrumented area and time of instrumentation were analyzed by Mann-Whitney U test and Kruskal-Wallis. Correlations among the number of uses and instrumented area were measured. The level of statistical significance was set at p < 0.05. Results: Reciproc Blue presented a higher estimated number of uses in comparison with WaveOne Gold (p = 0.026), but autoclaving did not affect the resistance to fracture of instruments (p > 0.05). The instrumented area was different among the evaluated groups (p = 0.039), and the instrumented area along the uses of both tested instruments was reduced. With the time of instrumentation, there was also a significant difference among the evaluated groups; the groups without sterilization cycles were faster, in comparison to those submitted to autoclaving (p = 0.010). Conclusions: Reciproc Blue was more resistant than WaveOne Gold, suffering later fracture. Additionally, the sterilization cycles did not influence the estimated number of uses of thermally treated reciprocating instruments, but the instrumented area of root canals was reduced along with the repeated uses of both instruments.