• Restorative Dentistry and Endodontics
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• 제16권1호
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• pp.74-86
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• 1991

The purpose of this study was to evaluate the resulting root canal angulation and shape change after using various enlarging instruments. The mesial canals (120) of extracted human mandibular 1st and 2nd molars were randomly divided into 6 groups; Control, K-type me, Heliapical me, Canal Master me, sonic and ultrasonic instrumentation group. Vertical angulation of each canal was determined by a straight line through the long axis of canal and another straight line through the apical foramen to intersect at the point where the canal began to leave the long axis of the tooth. By recording and comparing the measured angles of the each set of pre-and postinstrumentation. Then, the roots were sectioned horizontally in the apical, middle, coronal thirds and the canal shapes examined, as was the mesiodistal canal diameter as it relates to the external root surface. The results were as follows: 1. Instrumentation using K-type me group resulted in the highest mean change in angulation ($9.900^{\circ}$) (p < 0.005), while Sonic Air MM 3000 group resulted in the least degree of straightening canals ($8.250^{\circ}$) (p < 0.005). 2. Canal Master file group resulted in the best canal shape at the three levels (P < 0.005). 3. Measured minimal mesial root width produced Heliapical me group at the apical 1/3 level, Sonic Air MM 3000 group at the middle 1/3 level, Heliapical me group at the coronal 1/3 level (P < 0.005). 4. Measured minimal distal root width produced Sonic Air MM 3000 group at the apical 1/3 level (P < 0.05), Heliapical me group at the middle 1/3 level (P < 0.005), Canal Master me group at the coronal 1/3 level (P < 0.005). 5. HeIiapical me group produced more increased canal diameter than any other groups (P < 0.005).

• 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.

• Restorative Dentistry and Endodontics
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• 제46권1호
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• pp.14.1-14.7
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• 2021

Objectives: The aim of this study was to evaluate the apical pressure generated by 2 endodontic irrigation needles and the GentleWave system in mandibular molars. Materials and Methods: The mesial and distal root canals of 12 mandibular molars were irrigated with a 30-gauge close-end needle or with a 30-gauge open-end needle. Procedures were performed in the mesial and distal canals. The GentleWave procedure and irrigation at 1 mm from the apex in the distal roots using an open-end needle were used, respectively, as negative and positive controls. The apical pressure was measured using a data acquisition pressure setup. Apical pressure exerted by the different needles in the 2 different canal types was statistically compared using 2-way analysis of variance. Results: Significant differences were found in the apical pressure for both needles and the canal type. The lowest values were obtained with close-end needles and in mesial canals. Negative apical pressure values were obtained using GentleWave. Conclusions: The needle and the canal type influenced the apical pressure. The GentleWave procedure produced negative apical pressure.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제28권5호
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• pp.341-347
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• 2002

This study was designed to determine the location of the mandibular canal on lower molar areas. Thirty-three patients were examined with multi-planar reformatted CT scan($Dentascan^{(R)}$). Three kinds of measurements were performed. The first was the distances between the upper border of the mandibular canal and the root apices of the first and second molars, the second was the distance between the cortical plate of the mandible and mandibular canal, and the last was the location of the mandibular canal in the buccolingual plane. The obtained results are as follows 1. The distance between the root apices of lower molars and the superior border of mandibular canal was largest at the mesial root of the first molar, and shortest at the distal root of the second molar(p<0.05). 2. The longest distance between the outer surface of the buccal cortical plate of the mandible and mandibular canal was measured from the distal root of the second molar, and this distance decrease gradually mesially(p<0.05). 3. The distance between the mandibular base and inferior border of mandibular canal was longest at the distal root of the second molar, and shortest at the mesial root of the first molar(p<0.05). 4. The location of mandibular canal was lingually positioned in relation to the axis of teeth and alveolar ridge in molar areas.

• Restorative Dentistry and Endodontics
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• 제37권2호
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• pp.104-109
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• 2012

Objectives: The purpose of this study was to evaluate the buccolingual curvature at the apical one third in type II mesial canals of mandibular molars using the radius and angle of curvature. Materials and Methods: Total 100 mandibular molars were selected. Following an endodontic access in the teeth, their distal roots were removed. #15 H- or K-files (Dentsply Maillefer) were inserted into the mesiobuccal and mesiolingual canals of the teeth. Radiographs of the teeth were taken for the proximal view. Among them, type II canals were selected and divided into two subgroups, IIa and IIb. In type IIa, two separate canals merged into one canal before reaching the apex and in type IIb, two separate canals merged into one canal within the apical foramen. The radius and angle of curvature of specimens were examined. Results: In type II, mean radius of curvature in mesiolingual and mesiobuccal canals were 2.82 mm and 3.58 mm, respectively. The radius of the curvature of mesiolingual canals were significantly smaller than that of mesiobuccal canals in type II, and especially in type IIa. However, there were no statistically significant differences in radius of curvature between mesiobuccal and mesiolingual canals in type IIb and there were no significant differences in angle of curvature between type IIa and IIb. Conclusion: In this study, type II mesial canals of mandibular molars showed severe curvature in the proximal view. Especially, mesiolingual canals of type IIa had more abrupt curvature than mesiobuccal canals at the apical one third.

• Restorative Dentistry and Endodontics
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• 제30권6호
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• pp.477-485
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• 2005

근단부위 형성이 완료되고 우식이 없는 하악 대구치 근심치근 50개를 대상으로 주파수 의존형 전자근관장 측정기를 이용하여 측정한 근관장의 정확도를 평가하기 위해 치수강 개방 후 동일한 치아에서 방사선 사진으로 확인한 실측 근관장을 대조군, 각종 전자근관장 측정기로 측정한 근관장을 실험군 ( I군: Root-ZX, II군: Bingo, III군: Propex, IV군: Diagnostic)으로 분류하여 근심협측과 설측의 근관장을 근관의 입구 측으로부터 치근단 1/3까지 확대여부 및 서로 다른 측정시기에 측정하여 비교 평가한 결과 다음과 같은 결론을 얻었다. 하악대구치 근심치근의 협측과 설측 전자근관장은 측정기의 종류, 근관의 입구 측으로부터 치근단 1/3까지의 확대여부 및 측정시기에 상관없이 0.5mm이내의 오차범위를 나타내었으며, 근관치료시 오차한계인 ${\pm}1mm$에서 정확성은 근관의 입구 측으로부터 치근단 1/3까지 미리 확대한 후에 근관장을 측정할 경우와 측정시기가 반복될 경우에 증가되는 경향을 보여 임상에 유용하게 활용할 수 있을 것으로 사료된다.

• Restorative Dentistry and Endodontics
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• 제10권1호
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• pp.193-198
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• 1984

This study was conducted to compare the chip removal capability of root canal enlarging instruments. Fifty five buccal or mesial canals from upper and lower molar teeth were randomly selected and divided into three groups; Reamer, K-type file and K-flex file. Fifteen canals in each group were individually enlarged with one of three tested instruments and irrigated with 5cc of normal saline solution. After instrumentation, each canal was dried with paper point and the canal was splited longitudinally and the cleanness of root canal surface was evaluated under stereoscope by three observers. The results were as follows; 1. Most of the canals experimented showed varying degree of the presence of debris. 2. The canals prepared with reamers showed the most clean canal surface. 3. There was no significant difference in debridement effect between k-type file and k-flexfile.

• Imaging Science in Dentistry
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• 제51권4호
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• pp.373-382
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• 2021

Purpose: Cone-beam computed tomography (CBCT) reconstructions were analysed to elucidate factors affecting the anatomical relationship between tooth roots and the mandibular canal(MC). Materials and Methods: Images of 300 volumetric tomography scans of patients aged between 20 and 79 years old (167 women and 133 men) were analysed. The mean distances between 2,053 dental root apices and the internal border of the MC were obtained by measuring the horizontal and vertical distances on coronal CBCT images. The actual distance was then calculated mathematically with the Pythagorean formula. The statistical significance of differences between men and women was assessed using the Mann-Whitney test. Correlations with patient age were evaluated with the Spearman rank correlation coefficient. Results: The mean distances ranged from 2.17 mm, for single right third molar roots in women, to 8.02 mm for single left third molar mesiolingual roots in men. The mean distances measured for the mandibular right second molar mesial roots and the right second premolar roots were larger in men than in women. Age showed a significant positive correlation with the measured distances for mesial and distal roots of the first and second molar on both sides and the right third molar, mesiolingual roots of the left third molar, and single roots of the right third molar. Conclusion: The root-to-mandibular canal distance depended on age and the type of tooth. In 2 root types, this distance was impacted by sex.

• Restorative Dentistry and Endodontics
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• 제34권3호
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• pp.215-222
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• 2009

본 연구의 목적은 isthmus가 존재하는 하악 대구치의 근심 근관에서 근관세척방법에 따른 잔사제거효과를 평가하는 것이다. 45개의 하악 대구치의 근심근관을 #30 Profile .06까지 확대하였다. 각 근관을 3개의 군으로 나누고 conventional irrigation syringe와 초음파, RinsEndo를 사용하여 1분간 최종 세척하였다. 조직표본을 제작한 후, 광학현미경으로 치근단 1, 3, 5 mm 부위의 단면을 관찰하였다. 근관과 isthmus의 잔사 양으로 청결도를 계산하고 Mann-Whitney U test로 검정하였다. 1. 초음파 군과 syringe군은 5 mm부위의 isthmus를 제외한 나머지 부위에서 청결도의 유의한 차이가 없었다. 2. RinsEndo군은 syringe군에 비해 1 mm, 3 mm부위의 근관과, 모든 부위의 isthmus에서 유의하게 높은 청결도를 나타내었다 (p<0.05). 3.초음파 군과 RinsEndo군은 3mm부위의 근관을 제외한 나머지 부위에서 청결도의 유의한 차이가 없었다. 임상적으로 RinsEndo를 이용한 근관세척방법의 부가적인 적용이 하악 대구치의 근심근관의 잔사제거에 효과가 있을 것으로 사료된다.

• 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.