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To evaluate the efficacy of examinations by endoscope of root canals to determine residual root canal filling materials by comparison with microcomputed tomographic (micro-CT) images as reference.Thirty maxillary second premolars with oval canals received root canal treatment. Then D-Race retreatment files were used to remove the root canal fillings supplemented by XP-endo Finisher. Samples were scanned to reconstruct micro-CT reference images. Images were obtained of all samples from the mesiodistal and buccolingual directions by digital radiography. Then the root canals of specimens mounted in manikins were assessed by endoscope. The radiographic and endoscopic results were scored following comparison with the micro-CT images, which served as a reference, by 2 blinded observers. The interexaminer reliability of the assessments was evaluated by kappa test and the accuracy of endoscopic visualization according to the presence of residual root canal filling materials was compared using Kruskal-Wallis H test and Spearman's rank order correlation with the level of significance set at 5%.The efficiency of the periapical radiography and endoscopy to determine residual root canal filling material was similar in every third of the root canal (P .05).The endoscope detected residual root canal filling material as efficiently as periapical radiography.

Tam Metin / Full Text ESCI WOS:000618359700006 PMID: 33937760 PurposeThe aim of this study was to evaluate the efficacy of endoscopic visualisationto detect the presence and type of isthmuses within the mesial root canals ofmandibular first molar teeth compared with micro-computed tomography (micro-CT) images as reference.Materials and MethodsThirty-two mesial roots of mandibular first molars presenting isthmuses wereselected based on micro-CT scans. In all, 12 type I and 20 band-shaped isthmuseswere collected. The specimens were mounted in the posterior socket of dentalphantom manikin for endoscopic visualisation. The ability of endoscopes to visualizethe presence of isthmuses and distinguish the type of isthmuses was compared.Micro-CT images of the specimens were used as references. Data were analyzedusing Fisher’s exact tests.ResultsSensitivity of endoscope to detect isthmuses were also calculated for eachisthmus type. In 37.5% of the samples, isthmus presence was correctly diagnosedvia orthograde endoscopic visualization. Type I istmuses were significantly moredetected than band-shaped isthmuses (P

WOS: 000518755000001 PubMed: 32141355 Objective: The aim of this study was to investigate the accuracy of endoscopic visualization to detect root canal anastomoses at the coronal half of the mesial root canals of mandibular molars using micro-computed tomographic (micro-CT) images as reference. Material and methods: Seventy-four mesial roots of mandibular first molars with (n = 47) or without (n = 27) intercanal anastomosis were selected based on the micro-CT scans of 269 mandibular first molars at a pixel size of 10 mu m. The specimens were mounted on the mannequins and their root canals were evaluated using dental operating microscope (DOM) and endoscope. The endoscopic probe was inserted into the main mesial root canals and 2 blinded observers evaluated the presence of a divergence point of anastomosis (where the branching occurs) as 'present' or 'absent'. The scorings were compared with the three-dimensional reconstructed images of the specimens and recorded as 'correct' or 'incorrect' evaluation. Degree of agreement between evaluators was assessed with Kappa test and the accuracy of endoscopic visualization according to the presence and location of anastomosis was compared using Fisher exact tests with a significance threshold at 5%. Results: High inter-examiner reliability was reported (0.91). None of the divergence points were identified using DOM whereas 11 divergence points were detected using endoscope, corresponding the 23.4% of the intercanal anastomoses. The endoscope also showed the absence of an intercanal anastomosis correctly in all of the specimens without an anastomosis. Detectability of a divergence point using endoscope was not affected by its location within the coronal half of root canal (p > .05). Conclusions: The endoscopes were able to visualize the divergence points of 23.4% of the intercanal anastomoses located at the coronal halves of root canals. Scientific and Technological Research Council of Turkey-TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [117S139] This study was supported by the Scientific and Technological Research Council of Turkey-TUBITAK (grant no. 117S139).

Versiani, Marco/0000-0001-5277-9827; , Ali/0000-0003-2835-767X WOS: 000499493100001 PubMed: 31705697 Aim To evaluate, using micro-CT, the remaining dentine thickness after preparation of the mesiobuccal (MB), mesiolingual (ML) and middle mesial (MM) canals of mandibular first molars with the ProTaper Next rotary system. Methodology Eleven mesial roots of mandibular first molars having three independent canals from the furcation level up to at least 5 mm towards the apical direction were selected. Preparation of MM canals was performed in two steps using ProTaper Next X2 (step 1) and X3 (step 2) instruments, whilst MB and ML canals were prepared in a single step up to X3 instruments. The roots were scanned (pixel size of 10 mu m) before and after each step, and the dentine volume was calculated. Postoperative models of the roots were coregistered with their preoperative dataset and colour-coded cross-sections of the roots were used to measure the smallest dentine thickness surrounding each canal at 1.0-mm intervals from the furcation level up to 5 mm in the apical direction, in both mesial and distal aspects of the roots. Changes in the remaining wall thickness between mesial canals were analysed with repeated-measures anova and post hoc Tukey test. Significance level was set at 5%. Results Mean percentage reduction of dentine volume after steps 1 and 2 was 4.66% and 5.16%, respectively. Overall, pre- and postoperative dentine thickness of the MM canal walls, in both mesial and distal aspects of the root, were significantly thinner than those of MB and ML canals (P < 0.05). No significant difference was observed when comparing dentine thickness in the mesial and distal directions of MM canal after preparation step 1 (0.88 +/- 0.18 mm and 0.73 +/- 0.26 mm, respectively) or 2 (0.83 +/- 0.17 mm and 0.67 +/- 0.26 mm, respectively) (P > 0.05). Dentine thickness values less than 0.5 mm were observed mostly towards the distal aspect of the MM canal. Mesial roots were not associated with strip perforations after canal preparation procedures. Conclusions A significant decrease in the thickness of canal walls at all levels evaluated in the mesial roots of mandibular molars suggests that files with small tapers should be used in preference to instruments with large tapers to prepare mesial canals in mandibular molars. Ondokuz Mays University Research FundOndokuz Mayis University [PYO.DIS.1901.18.003] This study was supported by Ondokuz Mays University Research Fund (grant no. PYO.DIS.1901.18.003).