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This study assessed canal preparation effects on disinfection and dentin preservation. Thirty mandibular incisors were paired into two experimental groups (n = 10). Following contamination, the initial microbial sample was collected. Instruments 30/0.03 (Group 1) and 30/0.05 (Group 2) were employed and a second sample was obtained. Canals were enlarged using instruments 40/0.03 and 40/0.05, respectively, and a third sample was collected. Final irrigation was performed, and sample S4 obtained. A final scan evaluated volume, surface area, unprepared areas, removed dentin and dentin thickness. Data were analysed using Student t‐test, Mann–Whitney, Kruskal–Wallis and Dunn tests. A significant difference was observed between S1 and other time points (p < 0.05). Comparison between groups showed no differences in bacterial loads and in the percentage of microbial reduction (p > 0.05). Group 2 exhibited greater reduction in dentin thickness than group 1 in the mesial aspect of the root (p < 0.05). Instrument 30/0.03 might provide effective disinfection and safety during mandibular incisors canal preparation. [ABSTRACT FROM AUTHOR]

This study evaluated unprepared canal areas, volume of dentine removal, and dentine thickness after the progressive enlargement of the buccal canals of 22 maxillary molars, with and without the MB2, using instruments with the same tip size (0.25 mm) but 4 different tapers (0.03, 0.05, 0.06 and 0.08 v). Micro‐CT scans were performed after each instrument. Data were compared using a general linear mixed model post hoc comparisons with Kenward‐Roger for Wald F tests (α = 5%). After each treatment step, it was observed an increase in the percentage volume of removed dentine and a decrease in the unprepared areas and dentine thickness at the pericervical region of all canals (p < 0.05). The percentage reduction of dentine thickness in MB2 canal was higher than in the mesiobuccal and distobuccal canals (p < 0.05). Knowledge of pre‐operative dimensions and dentine thickness before enlargement of buccal canals of maxillary molars is an important factor to avoid excessive dentine removal. [ABSTRACT FROM AUTHOR]

This study assessed the influence of pH variation on the volumetric change of EndoSequence BC Sealer compared to AH Plus Jet. Eighteen single‐rooted teeth were uniformly prepared and filled with one of the sealers. After 24‐h storing, samples were scanned in a micro‐CT device. Then, roots were immersed in 20 ml phosphate‐buffered saline (PBS) with pH of 5, 7 or 12 at 37°C for 7 and 30 days and rescanned. Statistical analysis was performed using Shapiro–Wilk's test, one‐way ANOVA and Tukey's or Student's t‐tests (p < 0.05). Differences between sealers were observed only at neutral pH and after 30 days of acidic pH exposure, with a higher loss of EndoSequence (p < 0.05). After 7 days, alkaline pH reduced and increased the volumetric loss of EndoSequence and AH Plus, respectively, compared to neutral pH (p < 0.05). It can be concluded that the pH directly influenced the volumetric change of both tested root canal sealers in different ways. [ABSTRACT FROM AUTHOR]

Aim: This study aimed to evaluate the volumetric change of root canal sealers through micro‐computed tomographic analysis using a novel in vivo model and to compare the results with those obtained using an ex vivo test. Methodology: Eighteen single‐rooted teeth were cut to 5 mm length from the root apex. The root canals were uniformly enlarged and filled with EndoSequence BC Sealer or AH Plus Jet root canal sealers. Samples were stored at 37°C and 95% relative humidity for 24 h and then scanned with a micro‐CT device. Twelve samples (n = 6 for each sealer) were implanted in the subcutaneous tissue of Wistar rats, while six samples (n = 3 for each sealer) were immersed in 20 mL of phosphate‐buffered saline (PBS) at 37°C at neutral pH. After 7 and 30 days, teeth were removed from subcutaneous tissue or PBS and rescanned. Statistical analysis of volume changes was performed using Shapiro–Wilk's test and independent t‐test (p <.05). Results: AH Plus Jet had smaller volume changes (−2.2 to +0.77%) than EndoSequence BC Sealer (−2.0 to +4.0%) (p <.05), in the two tested models. The volume of the root canal sealers decreased over time (p <.05), in vivo. AH Plus Jet results varied between the in vivo and ex vivo results (p <.05), while EndoSequence BC Sealer presented similar volume losses for both experimental models (p >.05). Conclusion: EndoSequence BC Sealer lost more volume than AH Plus Jet. The experimental conditions influenced the volumetric change of AH Plus Jet but not the EndoSequence BC Sealer. The ex vivo model should be further explored as a methodological alternative to assess the volumetric changes of root canal sealers without causing harm to animals. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of glycolic acid (GA) and EDTA on dentin mechanical properties. For the cohesive strength, flexural strength and fracture strength tests, the hourglass of root dentin, dentin sticks and roots standardised to 1 mm thickness were used respectively. ANOVA and Tukey tests were used for statistical analysis (P < 0.05). The results showed that EDTA and GA 17% reduced the cohesive strength values when compared to distilled water (control; P = 0.0022 and P = 0.0016 respectively), whereas the values for GA 10% group were similar to those of the control group (P = 0.093). No statistically significant difference was found among the groups for the flexural strength test (P = 0.1974). Fracture strength test showed that EDTA and GA 17% were statistically similar to each other (P = 0.7694) and statistically inferior to GA 10% (P = 0.0007 and P = 0.0004 respectively). It was concluded that 10% GA showed fewer negative effects on dentin mechanical properties. [ABSTRACT FROM AUTHOR]

A root‐end filling material is required to fill the root‐end cavity without gaps or voids, to prevent root canal reinfection and to provide periapical healing. Thus, this study evaluated the volume of marginal gaps and voids of three root‐end filling materials using microcomputed tomography (micro‐CT). Thirty maxillary incisors were prepared and filled with gutta‐percha and endodontic sealer. The specimens were scanned using micro‐CT and distributed into three groups (n = 10): White MTA, MTA Repair HP, and Bio‐C Repair. The root tips were resected at 90° to the longitudinal axis and the cavity (3 mm depth) was prepared with an ultrasonic tip. The materials were handled, and the cavities were filled. The specimens were rescanned and the percentual volume of gaps and voids were analyzed. The data were analyzed using Kruskal–Wallis and Dunn tests (p <.05). No statistical difference was found in the percentage of gaps among the tested materials (p >.05). White MTA presented less voids than Bio‐C and MTA Repair HP (p <.05). The materials presented a similar percentual volume of gaps and White MTA presented less voids than other tested materials. [ABSTRACT FROM AUTHOR]

Aim Methodology Results Conclusion To investigate the development of dentinal microcracks resulting from the progressive enlargement of the buccal canals of maxillary molars with and without the MB2 canal employing instruments with the same tip and four different tapers.Twenty maxillary molars with (n = 10) and without (n = 10) the MB2 canal underwent micro‐CT scanning. Their mesiobuccal and distobuccal canals were sequentially enlarged using nickel–titanium instruments with sizes 25/.03, 25/.05, 25/.06 and 25/.08v. Subsequent scans were conducted after each canal enlargement. The preoperative scans were coregistered with their respective datasets, and the cross‐sectional images were carefully examined to identify dentinal defects. This process, conducted twice at two‐week intervals, involved two examiners. Intra‐ and inter‐examiner calibrations were validated using the Kappa index. The incidence of microcracks was reported as a percentage frequency.The intra‐ and inter‐examiner Kappa values were 0.85 and 0.88, respectively, indicating excellent agreement. Dentinal microcracks were detected in 1206 out of 42 975 cross‐sectional image slices (2.8%). Molars with MB2 canal exhibited more slices (4.5%) than teeth without MB2 (0.9%). Every dentinal microcrack observed in the images after root canal preparation was already present in the corresponding images taken before root canal preparation.The progressive enlargement of root canals using instruments with different tapers did not induce the formation of new dentinal microcracks in maxillary molars, regardless of the presence of the MB2 canal. [ABSTRACT FROM AUTHOR]