• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.29 no.1
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• pp.43-53
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• 1999

Purpose: The aim of this study was to analyze radiologically the location and course of the mandibular canal and to observe the alveolar and basal bone changes during the remodeling procedures of atrophic mandible. Materials and Methods: CT scanning was performed on dry 30 edentulous or partially dentulous mandibles. In 48 edentulous lower halves, measuring areas were determined by three points in the length of the mandibular canal. The distance from the mandibular canal towards cranial and caudal edges, buccal and lingual external borders of the body of the mandible were measured. A statistical comparison between the mean values of different classes of mandibular body was carried out in the selected areas. Results: The distance between the mandibular canal and caudal borders of the body of the mandible and lingual borders dose not change in the atrophic process of mandible. The mandibular canal within the mandible courses downwards from mandibular foramen towards mesial and subsequently it gets to the mental foramen. The distance between the mandibular canal and buccal external border of basal bone changes similar to the change of cranial borders of alveolar bone in the atrophic process of mandible. Conclusion: CT scanning was very effective and practicable to analyze the location and course of the mandibular canal and to observe the alveolar and basal bone changes of atrophic mandible. Also more detailed investigation of basal bone changes observed during the remodeling procedures of atrophic mandibles seems reasonable to rely on the massive anthropologic collections of atrophic mandibles combined with CT scanning.

• Restorative Dentistry and Endodontics
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• v.3 no.1
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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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• v.38 no.3
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• pp.154-159
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• 2013

Objectives: The aim of this study was to compare the cleaning efficacy of different final irrigation regimens in canal and isthmus of mandibular molars, and to evaluate the influence of related variables on cleaning efficacy of the irrigation systems. Materials and Methods: Mesial root canals from 60 mandibular molars were prepared and divided into 4 experimental groups according to the final irrigation technique: Group C, syringe irrigation; Group U, ultrasonics activation; Group SC, VPro StreamClean irrigation; Group EV, EndoVac irrigation. Cross-sections at 1, 3 and 5 mm levels from the apex were examined to calculate remaining debris area in the canal and isthmus spaces. Statistical analysis was completed by using Kruskal-Wallis test and Mann-Whitney U test for comparison among groups, and multivariate linear analysis to identify the significant variables (regular replenishment of irrigant, vapor lock management, and ultrasonic activation of irrigant) affecting the cleaning efficacy of the experimental groups. Results: Group SC and EV showed significantly higher canal cleanliness values than group C and U at 1 mm level (p < 0.05), and higher isthmus cleanliness values than group U at 3 mm and all levels of group C (p < 0.05). Multivariate linear regression analysis demonstrated that all variables had independent positive correlation at 1 mm level of canal and at all levels of isthmus with statistical significances. Conclusions: Both VPro StreamClean and EndoVac system showed favorable result as final irrigation regimens for cleaning debris in the complicated root canal system having curved canal and/or isthmus. The debridement of the isthmi significantly depends on the variables rather than the canals.

• The Journal of the Korean dental association
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• v.16 no.12 s.115
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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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• v.9 no.1
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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.

• Restorative Dentistry and Endodontics
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• v.2 no.1
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• pp.27-31
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• 1976

Eighty mandibular first 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 22.5% of the teeth were found to have bifurcated or trifurcated canals. 2. Of the 99 canals studied, 37.3% of the canals were found to have lateral canals and these ramifications were usually located in the apical third of the root. 3. 27 apical foramens were located directly on the root apex and 66 foramens laterally. 4. 6 canals showed mesial curvature, 49 canals distal curvature, 11 canals buccal curvature, and 25 canals lingual curvature.

• Restorative Dentistry and Endodontics
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• v.10 no.1
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• pp.183-186
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• 1984

Thirty maxillary lateral incisors 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 6.7% of the teeth were found to have bifurcated canals. 2. Of the 32 canals studied, 37.5% of the canals were found to have lateral canals and these ramifications were usually located in the and apical third of the root. 3. 9 apical foramens were located directly on the root apex and 21 foramens laterally. 4. 3 canals showed mesial curvature, 20 canals distal curvature, 4 canals labial curvature, and 3 canals palatal curvature.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.388-395
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• 1997

Maintaining the original canal path during instrumentation is a challenge in narrow curved canals. This study compared the maintenance of the original canal path of curved root canals during instrumentation with two kinds of stainless steel K-files(Brassler USA & Mani Japan), K-flexofiles(Maillefer Swiss) and Ni-Ti files(Brassler USA, Savannah, GA) using circumferential filing technique to # 40 MAF on 60 extracted human molars. Buccal and mesial canals with minimal initial curvature of 20 degrees were used. The maximal initial curvature was 41.5 degrees. Sixty curved canals divided into four groups according to file type(Group 1 : Ni-Ti file, Group 2 : K-flexofile, Group 3: K-file(Brassler), Group 4 : K-file(Mani)). Radiographs of canals were obtained before and after canal shaping. And postoperative radiographs were compared with preoperative radiographs using superimposition method. Data analysis was performed using Covariance analysis and paired-comparison test. The results observed were as follow ; 1. The angle of curvature was better maintained with Ni-Ti file than with stainless steel files. (p<0.01) 2. There was no significant difference in maintaining canal curvature between K-flexofile, Brassler$^{(R)}$ K-file and Mani$^{(R)}$ K-file, although there was some differences in mean values of postoperative canal curvature. 3. Paired-comparison t test revealed significant differences within each of the three stainless steel file types when comparing the mean differences before and after instrumentation, but no significant differences were observed within Ni-Ti file group.

• Restorative Dentistry and Endodontics
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• v.24 no.4
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• pp.623-627
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• 1999

During canal instrumentation of a curved canal, restoring force of endodontic instrument remove more dentin from the inner wall of the curvature. This effect tends to straighten the canal and thus may significantly shorten the working length. This study was to determine the mean reduction in working length after instrumentation according to the curvature. The curvature of mandibular mesial root was determined before instrumentation. 30 canals were divided into 3 groups each 10 on the basis of degree of curvature. Experimental groups as follows. In group 1, canals having curvature from 15 to 20 degrees: in group 2, canals having curvature from 20 to 30degrees; in group 3, canals having curvature above 30 degrees. Experimental teeth in all groups were accessed, and their actual working length determined by passing a size 15 K-file(IAF) just through the minor apical foramen. The canals were sequentially enlarged to size 35 with ProFile .06 series. The change of working length was calculated by measuring the tip of IAF beyond apical foramen by using stereomicroscope. The change of canal curvature following instrumentation were measured using the Schneider technique. The results were as follows. 1. The greatest changes of curvature and working length were observed in the group 3 canals(P<0.05), next were group 2 canals and group 1 canals(P>0.05). 2. Group 1 canals showed a mean reduction in 1.61 degrees and length of 0.12m respectively(P>0.05). 3. Group 2 canals showed a mean reduction in 3.42 degrees(P<0.05) and length of 0.25mm(P>0.05) respectively. 4. Group 3 canals showed a mean reduction in 7.23 degrees(<0.05) and length of 0.64mm respectively(P<0.05).

• The Journal of the Korean dental association
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• v.13 no.5
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• pp.415-416
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• 1975

1. The author have had a case of class V and class Ⅲ combined carious lesion extended on to root surface of upper right lateral incisor. 2. The patient was 40 years old female. 3. After routine root canal treatment of the tooth, the gingival flap was made by vertical incision on gingival tissue between distal surface of upper right lateral incisor and mesial surface of upper right canine. 4. Cavity preparation and amalgam filling on the carious lesion were performed and the flap was sutured.