• Restorative Dentistry and Endodontics
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• 제15권2호
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• pp.115-121
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• 1990

Forty extracted human mandibular second molars with C-shaped canal were chosen to study the anatomy of the root canal. The experimental teeth were injected with china ink, decalcified and cleared with Winter green oil, in vitro, to study the number of root, root canal, canal per root, frequency and location of lateral canal and transverse anastomosis. 1. All teedth had one root. 2. Mesial roots with two canals were 25%, and mesial roots with one canal were 75%. All distal roots had one canal. 3. In the roots with two canals, the common apical foramen appeared in 20% and the separte apical foramen appeared in 80%. 4. The frequence of lateral canal was 33.3% and the most frequent region was middle 1/3. 5. All teeth had the transverse anastomosis in all region of the roots.

• Restorative Dentistry and Endodontics
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• 제4권1호
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• pp.23-27
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• 1978

Fifty two mandibular permanent canines were chosen to study the anatomy of the root canal. The experimental teeth were injected with China ink, decalcified, cleared and observed to investigate the number of root canals, frequency and location of lateral canals, the location of apical foramens, the frequency of apical deltas, and the curvature of root canals. The results were as follows: 1) all of the experimental teeth demonstrated single canal. 2) of the 52 canals, 9.6% of the canals were found to have lateral canals and the locations of the lateral canals were in the apical third of the roots 3) Thirty three apical foramens were located laterally on the root apices and nineteen foramens were located on the centers of the root apices. 4) 37 canals showed straight curvature, 12 canals distal curvature. 3 canals labial curvature.

• 대한치과의사협회지
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• 제57권7호
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• pp.392-402
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• 2019

The most important part of everyday root canal treatment is diagnosis about the morphology of tooth, root and root canal. Usually this procedure is performed by visual examination and radiographic (panoramic/periapical) examination. However, 2-dimentional radiography has several limitations such as imposition of anatomic structures including buccal/lingual root canals and distortion of images. Recently, owing to the increased interest in dental implant and affordable cost of CBCT equipment, CBCT has been introduced widely in local dental clinics. CBCT is characterized by their lower radiation dose and shorter exposure time than conventional CT scan, and ability of 3-dimentional reconstruction of the dento-alveolar structure. Also in endodontic field, the data from CBCT could be very helpful in diagnosing complex root canal anatomy, apical periodontitis, cause of failure and in determining treatment plan. However, there are some limitations such as radiation dose and artifact. Therefore, clinicians should know about indication, advantages and limitations of CBCT, and properly use it for successful root canal treatment to save the natural teeth.

• Restorative Dentistry and Endodontics
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• 제3권1호
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• pp.7-11
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• 1977

One hundred and thirteen human mandibular first molars were injected with china ink, decalcified, cleared and used in study, in vitro, to determine the number of root, the number of root canals, canals per root, frequency and location of transverse anastomoses, frequency and location of lateral canals and frequency of the apical deltas. The results were as follows; 1. Most of the teeth showed three canals, but 21. 25% of the teeth were found to have two canals and 21. 25% of them four canals. 2. In so far as observing two canals per root, 77.0% of teeth were found to have two canals in mesial root and 25.7% of them in distal root. 3. In roots with two canals, the separated apical foramen appeared 59.8% in mesial side and 40.0% in distal side, and the common apical foramen 40.2% in mesial side and 60.0% in distal side. 4. Of the two root canals in one root, 37.3% of the canals were found to have transverse anastomoses and were usually located in the apical third of the root. 5. 25.7% of 113 teeth were found to have lateral canals, and ramifications were mainly located in the apical third of the root.

• Restorative Dentistry and Endodontics
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• 제5권1호
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• pp.47-51
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• 1979

Fifty two human mandibular second molars were chosen to study the anatomy of the root canal. The experimental teeth were injected with china ink, decalcified, cleared and used in study, in vitro, to determine the number of root, the number of root canals, canals per root, frequency and location of transverse anastomoses, frequency and location of lateral canals and frequency of the apical deltas. The results were as follows; 1. Most of the teeth showed three canals, but 19.2% of the teeth were found to have two canals and 9.6% of them four canals. 2. In so far as observing two canals per root, 80.8% of the teeth were found to have two canals in mesial root and 9.6% of them in distal canal. 3. In roots with, two canals, the seperated apical foramen appeared in 59.5% in mesial side and 40.0% in distal side, and the common apical foramen appeared in 40.5% in mesial side and 60.0% in distal side. 4. Of the two root canals in one root, 36.2% of the canals were found to have transverse anastomoses and were usually located in the apical third of the root. 5. 23.1% of 52 teeth were found to have lateral canals, and ramifications were mainly located in the apical third of the root.

• 열병합발전
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• 통권30호
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• pp.21-25
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• 2002

According to recent Korea Electric Power Company report, yearly distribution line brass cramp bolts failure summed up to 4,400 cases emerging as one of main local break-down causes. Naturally, the need for the investigation was proposed To determine the root cause of the cramp bolt failures, mechanical and metallurgical investigation were performed for 90 samples which collected from various sites. For the understanding of the geometric characteristics, stress distribution was evaluated by CAE program and proof load of each bolts was tested. The SEM&EDS was used for metallurgical investigation. Through the investigation, the root causes of failures were confirmed. All damaged bolts showed intergrannular fracture mode and the all fractured bolt showed ß phase morphology contrast to the a&ß mixture morphology of the non-damaged samples. Additionally, EDS analysis confirmed the existence of lead rich layer on grain boundaries.

• Restorative Dentistry and Endodontics
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• 제12권2호
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• pp.11-15
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• 1987

Thirty maxillary second premolars were fixed, decalcified, washed and embedded in celloidin to observe the root canal size and morphology at apical 5mm area. The results were as follows: 1. Single canaled teeth and two canaled teeth were approximately equal numbered. 2. Single canaled teeth have round canal but two canaled teeth have long, slender buccal canal and ovoid lingual canal. 3. The canal size of single canaled teeth was $380{\pm}30{\mu}m,\;340{\pm}22{\mu}m$, but that of buccal canal of two canaled teeth was $360{\pm}32{\mu}m,\;240{\pm}28{\mu}m$, lingual canal was $330{\pm}28{\mu}m,\;280{\pm}20{\mu}m$.

• 대한치과의사협회지
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• 제15권11호
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• pp.753-756
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• 1977

Eighty-two maxillary canine were injected with china ink, decalcified, cleared and used in a study, in vitro, to determine the number of root canals, the frequency and location of lateral canals, the location of apical foramens, and the curvature of root canals. The results were as follows; 1.All of the maxillary canines showed the single canals. 2. Of the 82 canals studied, 20.7% of the canals were found to have lateral canals and most ramification of them were located in the apical third of the root. 3. In the case of the curvature, the mesial curvature of the canals (40.3%) usually showed more than the distal curvature of them (13.4%) 4. 41.2% of the apical foramen were located directly on the root apex and 58.5% of them laterally.

• 대한치과의사협회지
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• 제16권12호통권115호
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• pp.929-933
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• 1978

Sixty six mandibular incisor were injected with China ink, decalcified, cleared and used to study the number of root canals, the frequency and location of lateral canals, the location of apical foramens, the frequency of apical deltas, and the curvature of root canals. The results were as follows: 1. Most of the teeth demonstrated single canal, but 19.7% of the teeth were found to have bifurcated canals. 2. 12% of the teeth were found to have lateral canals and these ramifications were located in the apical third of the root. 3. 25 apical foramens were located directly on the root apex and 41 foramens laterally. 4. 43 canals showed straight, 7 canals distal curvature, 7 labial curvature, 3 mesial curvature.

• Restorative Dentistry and Endodontics
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• 제9권1호
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• pp.121-125
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• 1983

Thirty eight mandibular second premolars were injected with china ink, decalcified, cleared and used in an in vitro study to determine the number of root canals, the frequency and location of lateral canals, the location of apical foramens, the frequency of apical deltas, and the curvature of root canals. The results were as follows: 1. Most of the teeth demonstrated single canal, but 5.3% of the teeth were found to have bifurcated or trifurcated canals. 2. Of the 40 canals studied, 52.5% of the canals were found to have lateral canals and these ramifications were usually located in the apical third of the root. 3. 7 apical foramens were located directly on the root apex and 31 foramens laterally. 4. 4 canals showed mesial curvature, 20 canals distal curvature, 11 canals buccal curvature, and 8 canals lingual curvature.