• Restorative Dentistry and Endodontics
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• 제40권4호
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• pp.286-289
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• 2015

Objectives: The aim was to evaluate dentinal crack formation after root canal preparation with ProTaper Next system (PTN) with and without a glide path. Materials and Methods: Forty-five mesial roots of mandibular first molars were selected. Fifteen teeth were left unprepared and served as controls. The experimental groups consist of mesiobuccal and mesiolingual root canals of remaining 30 teeth, which were divided into 2 groups (n = 15): Group PG/PTN, glide path was created with ProGlider (PG) and then canals were shaped with PTN system; Group PTN, glide path was not prepared and canals were shaped with PTN system only. All roots were sectioned perpendicular to the long axis at 1, 2, 3, 4, 6, and 8 mm from the apex, and the sections were observed under a stereomicroscope. The presence/absence of cracks was recorded. Data were analyzed with chi-square tests with Yates correction. Results: There were no significant differences in crack formation between the PTN with and without glide path preparation. The incidence of cracks observed in PG/PTN and PTN groups was 17.8% and 28.9%, respectively. Conclusions: The creation of a glide path with ProGlider before ProTaper Next rotary system did not influence dentinal crack formation in root canals.

• Restorative Dentistry and Endodontics
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• 제34권2호
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• pp.137-144
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• 2009

본 연구는 한국인의 하악 제1 대구치 60개를 대상으로 생리적 근단공의 크기와 형태, 근심 치근의 치근단 3mm에서 isthmus의 발생 빈도와 형태, 그리고 원심 치근의 치근단 3mm의 근관 형태를 입체현미경하에서 60배로 조사한 결과 다음과 같은 결론을 얻었다. 1.근심 치근은 두 개의 근단공을 가지는 비율이 높았으며(51.67%), 원심 치근은 하나의 근단공을 가지는 비율이 높았다(71.66%). 2. 부근단공의 빈도는 근심 치근의 1개의 근단공을 가지는 경우가 가장 높았다(26.07%) 3. 생리적 근단공의 크기는 근심 치근에서 하나의 근단공을 가지는 경우 0.329mm, 근심 협측 근단공은 0.266mm, 근심 설측 근단공은 0.246mm였으며, 원심 치근에서 하나의 근단공을 가지는 경우 0.375mm, 원심 협측 근단공은 0.291mm, 원심 설측 근단공은 0.237mm로 나타났다. 4. 근단공의 형태는 oval 형태 (69.93%)가 가장 많았다. 5.근심 치근의 치근단 3mm에서 isthmus의 발생빈도는 55%였으며, partial isthmus는 31.66%, complete isth-mus는 23.34%로 나타났다. 6.원심 치근의 치근단 3mm의 근관 형태는 oval형태(50.64%)가 가장 많았다. 이상의 연구 결과 하악 제1대구치의 성공적인 근관 치료를 위해서는 생리적 근단공의 실제 크기와 형태 및 isthmus의 존재에 대한사전 지식이 필요할 것이다.

• Restorative Dentistry and Endodontics
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• 제45권1호
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• pp.7.1-7.9
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• 2020

Objectives: This study was performed to assess the anatomy of mandibular first molars. Materials and Methods: In this in vivo study, cone-beam computed tomography (CBCT) volumes of 312 bilateral intact first mandibular molars from 156 patients (79 men and 77 women; average age, 35.6 ± 11.2 years) were investigated in terms of the direction of each canal's curvature in the buccolingual and mesiodistal dimensions (direction of the position of the apex in relation to the longitudinal axis of the root), the presence of an isthmus (a narrow, ribbon-shaped communication between 2 root canals) in 3 segments (0-2, 2-4, and 4-6 mm) from the apex), and the presence and number of accessory canals (smaller canals besides the main root canals, connecting the pulp to the periodontium). Data were analyzed statistically (α = 0.05). Results: Mesiolingual canals were mostly buccally and distally inclined, while mesiobuccal and distolingual canals were mostly distally curved. Isthmuses were more common in younger patients (χ² test, p < 0.05). The average numbers of accessory canals in the apical, middle, and coronal segments were 9.9 ± 4.2, 6.9 ± 2.9, and 9.3 ± 3.0 canals per segment, respectively (analysis of variance, p < 0.001). Age and sex were not associated with the number of accessory canals (p > 0.05). Conclusions: The complex anatomy of these teeth deserves attention during non-surgical or surgical endodontic treatment. Around the apex, isthmuses might be more prevalent in younger and female individuals.

• Restorative Dentistry and Endodontics
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• 제43권4호
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• pp.46.1-46.10
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• 2018

Objectives: This study was to evaluate the antibacterial effect of different instrumentation and irrigation techniques using confocal laser scanning microscopy (CLSM) after root canal inoculation with Enterococcus faecalis (E. faecalis). Materials and Methods: Mesiobuccal and mesiolingual canals of extracted mandibular molars were apically enlarged up to a size 25 hand K-file, then autoclaved and inoculated with E. faecalis. The samples were randomly divided into 4 main groups according to the system of instrumentation and irrigation: an XP-endo Shaper (XPS) combined with conventional irrigation (XPS/C) or an XP-endo Finisher (XPF) (XPS/XPF), and iRaCe combined with conventional irrigation (iRaCe/C) or combined with an XPF (iRaCe/XPF). A middle-third sample was taken from each group, and then the bacterial reduction was evaluated using CLSM at a depth of $50{\mu}m$ inside the dentinal tubules. The ratio of red fluorescence (dead cells) to green-and-red fluorescence (live and dead cells) represented the percentage of bacterial reduction. The data were then statistically analyzed using the Kruskal-Wallis test for comparisons across the groups and the Dunn test was used for pairwise comparisons. Results: The instrumentation and irrigation techniques had a significant effect on bacterial reduction (p < 0.05). The iRaCe/XPF group showed the strongest effect, followed by the XPS/XPF and XPS/C group, while the iRaCe/C group had the weakest effect. Conclusions: Combining iRaCe with XPF improved its bacterial reduction effect, while combining XPS with XPF did not yield a significant improvement in its ability to reduce bacteria at a depth of $50{\mu}m$ in the dentinal tubules.