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This study aimed to evaluate the influence of temperature on torsional strength and angular deflection of two experimental NiTi rotary instruments manufactured from Blue and Gold thermal treatments and with identical cross-sections. A total of 40 experimental NiTi instruments 25.06 and with a triangular cross-section and manufactured from Blue and Gold thermal treatments were used (n=20). The torsional test was performed in the 3 mm from the tip of the instrument according to ISO 3630-1. The torsional test evaluated the torsional strength and angular deflection to failure at room temperature (21°C ± 1° C) and body temperature (36°C ±1°C). The fractured surface of each fragment was observed by using scanning electron microscopy (SEM). Data were analyzed using an unpaired t test for inter and intra-group comparison and the level of significance was set at 5%. The results showed that the body temperature did not affect the torsional strength and angular deflection of the instruments when compared with room temperature (P>0.05). However, at body temperature, the Blue NiTi instruments presented significantly lower angular deflection in comparison with Gold NiTi instruments (P0.05). The temperature did not affect the torsional strength of the instruments manufactured from Blue and Gold technology. However, the Blue NiTi instruments presented significantly lower angular deflection than Gold instruments at 36°C temperature.

This study aimed to evaluate physicochemical properties of three ready-to-use calcium silicate-based endodontic sealers: Endosequence BC Sealer, Bio C Sealer, and Sealer Plus BC. Radiopacity was evaluated using specimens of 10 mm in diameter and 1 mm in height, along with an aluminum step wedge. For the flow test, 0.5 mL of each sealer was deposited between glass plates and the mean of the measurement of two diameters was considered the cement flow value. For pH and calcium release, root canals of 30 prototypes of upper incisor acrylic resin teeth were filled with sealer and gutta percha point and then immersed in containers with 13 mL of ultrapure water. Both pH and release of calcium ions (atomic absorption spectrophotometer) were measured at 3, 24, 72, and 168 h. Acrylic resin teeth were scanned by Micro-CT 1174 at the time of pH and calcium ion readings for volumetric change analysis. The data were analyzed by ANOVA, Tukey’s, Kruskal-Wallis, and Dunn’s tests. Endosequence BC Sealer presented the lowest, and Bio C Sealer the highest volumetric change after 72 h and 168 h (p < 0.05). Endosequence BC Sealer presented higher radiopacity (p < 0.05). All materials showed alkalinization capacity. All of them presented calcium ion release, with a higher value for Sealer Plus BC. All materials presented alkalinization, calcium release capacity, radiopacity, and flow above the minimum values required by the ISO standard. The highest volumetric loss was experienced by Bio C Sealer and the lowest one by Endosequence BC Sealer.

Isthmuses are reported as common anatomic complexities in teeth often associated with failures in endodontic treatment. They should be considered before starting treatment and a preoperative computed tomography scan (CT) may demonstrate these complexities. Objective To assess the diagnostic value of the highest resolution settings of a cone-beam CT (CBCT) system in identifying and measuring apical isthmuses, using micro-CT as reference. Methodology After micro-CT scanning, 40 humans’ lower first molars with isthmuses in the apical-3 mm of mesial roots were scanned by the highest resolution settings of the New Generation i-Cat ® CBCT equipment. Two blinded observers recorded the detection of isthmuses in CBCT scans. The lengths of isthmuses were compared between micro-CT and CBCT to assess the diagnostic value of CBCT. Quantitative data for sensitivity were represented as percentages (95% confidence interval). The Bland-Altman method was used to assess differences between gold standard lengths (micro-CT) and CBCT lengths. Results BCT demonstrated 30 positive findings, representing sensitivity for isthmus identification of 75% (95% CI=0.4114–1.1364). Differences between the lengths in micro-CT (1.99±0.40 mm) and CBCT (1.53±0.41 mm) were significant (p