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The aim of this study was to evaluate the cyclic fatigue resistance of different heat-treated nickel-titanium reciprocating instruments in 2 different situations: new and used instruments after preparing 3 curved canals.A total sample of 60 nickel-titanium instruments of 3 systems (n = 20 per system) were used in this study: ProDesign R (tip 25, 0.06 taper; Easy Dental Equipment, Belo Horizonte, Brazil), Reciproc Blue (tip 25, 0.08v taper; VDW, Munich, Germany), and WaveOne Gold (tip 25, 0.07v taper; Dentsply Sirona, Ballaigues, Switzerland). Thirty new instruments (n = 10 per system) were used to prepare 90 curved single-rooted mandibular premolars (n = 30). Each instrument was used to prepare 3 root canals, and after each canal preparation the instrument was ultrasonic cleaned and submitted to autoclave sterilization procedures. The other 30 instruments (n = 10 per system) were kept without use. Then, the new and used instruments were subjected to the cyclic fatigue test in an artificial canal with a 30° angle and a 5-mm radius of curvature. The time and number of cycles to fatigue were recorded. Data were analyzed using the unpaired t test for intragroup comparison. For intergroup comparison, analysis of variance and the Tukey test for multiple comparisons were used.The intergroup comparison of new instruments showed that ProDesign R had the highest cyclic fatigue resistance followed by Reciproc Blue and WaveOne Gold (P.05). Regarding the used instruments, WaveOne Gold had the lowest cyclic fatigue resistance (P.05). The intragroup comparison between new and used instruments showed that WaveOne Gold and ProDesign R presented a significant reduction in the cyclic fatigue resistance after simulated clinical use (P.05); no difference was found with the Reciproc Blue instruments (P.05).ProDesign R had the highest cyclic fatigue resistance, whereas WaveOne Gold had the lowest for new and used instruments. Simulated clinical use affected the cyclic fatigue resistance of ProDesign R and WaveOne Gold but not of Reciproc Blue instruments.

This study aimed to use micro-computed tomographic imaging to analyze the quality of the endodontic preparation of mesial canals in mandibular molars provided by 3 instrumentation protocols.Forty-five extracted mandibular molars with 2 independent mesial canals were selected, and the initial micro-computed tomographic imaging was performed. The initial volume values of the canals were submitted to statistical analysis for paired division. The groups were determined according to the final enlargement of the canal and the working length adopted (ie, G25.06/+1 mm, G35.05/foramen, and G50.01/-1 mm). At the end of each instrumentation sequence, the root canals were scanned and analyzed with regard to the increase in the total and apical volume, centralization, and preparation transportation and the percentage of the total and apical uninstrumented walls.For the intragroup comparison, the Wilcoxon test was used, and for the intergroup analysis, the Kruskal-Wallis and Dunn tests were used (P .05). In the analysis of the canal total volume, a statistical difference was found between G25.06/+1 mm and the remaining groups (P .05). In the apical third, a statistical difference was observed between G25.06/+1 mm and G50.01/-1 mm (P .05). No statistical difference was found between the groups in terms of centralization and transportation of the preparation or in terms of the percentage of the total or apical uninstrumented walls.The preparation of the mesial canals of mandibular molars up to larger tip files but with a lower taper at 1 mm before the foramen resulted in a larger volume of apical preparation, kept the preparation centralized, and provided safe apical dentin wear without excessive cervical wear.

This study aimed to analyze the chemical-physical properties, including pH, volumetric change, radiopacity, and apatite-forming ability in simulated body fluid, of a new tricalcium silicate material (MTA Flow; Ultradent Products Inc, South Jordan, UT).MTA Flow was tested in comparison with MTA Angelus (Angelus, Londrina, PR, Brazil). The pH of soaking water was tested up to 168 hours in deionized water. In the solubility test, the root-end fillings of 20 acrylic teeth were scanned twice by micro-computed tomographic imaging before and after immersion in ultrapure water for 168 hours. In addition, using an aluminum step wedge, the radiopacity of each material was evaluated as recommended by international standards. The mean gray values of the test materials were measured using ImageJ software (National Institutes of Health, Bethesda, MD). The morphologic and chemical analyses of the material surface were performed using scanning electron microscopic energy-dispersive X-ray spectroscopic analysis after 28 days in Hank's balanced salt solution (HBSS). The data were analyzed using 2-way analysis of variance with the Student-Newman-Keuls test (P .05).MTA Flow showed similar alkalizing activity to that of MTA Angelus. In the solubility test, both materials presented lower values without statistical differences. Both materials showed a marked alkalinizing activity within 3 hours, which continued for 168 hours. MTA Angelus showed statistically higher radiopacity values (P .05). All materials showed the ability to nucleate calcium phosphate on their surface after 28 days in HBSS.MTA Flow showed remarkable alkalinizing capability, low solubility, good radiopacity, and the ability to form calcium phosphate deposits after being soaked in simulated body fluid, showing values similar to those of MTA Angelus.

Made available in DSpace on 2018-11-26T17:15:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-01-01 Introduction: The objective of the present study was to evaluate the in vitro antibiofilm activity and pH of calcium hydroxide associated with different nonsteroidal anti-inflammatory drugs (NSAIDs). Methods: The groups analyzed were as follows: group 1, calcium hydroxide paste with propylene glycol; group 2, calcium hydroxide paste with propylene glycol + 5% diclofenac sodium; group 3, calcium hydroxide paste with propylene glycol + 5% ibuprofen; group 4, calcium hydroxide paste with propylene glycol + 5% ciprofloxacin; and group 6, positive control (without medication). For analysis of the pH, the pastes were inserted into tubes and immersed in flasks containing ultrapure water. At the time intervals of 3, 24, 72, and 168 hours, the pH was measured with a calibrated pH meter. For microbial analysis, biofilm was induced in 30 bovine dentin blocks for 21 days. Subsequently, the pastes were placed on the blocks with biofilm for 7 days. Afterward, the pastes were removed by irrigation with sterile water, and the specimens were analyzed with a laser scanning confocal microscope with the 50 mu L Live/Dead BacLight Bacterial Viability solution L7012 Kit (Molecular Probes, Inc, Eugene, OR). Data were subjected to statistical analysis at a significance level of 5%. Results: The highest pH values were found for calcium hydroxide associated with ciprofloxacin in all periods analyzed. With the exception of pure calcium hydroxide paste, the other groups showed statistically significant differences (P

The purpose of this study was to evaluate the accuracy of small-volume cone-beam computed tomography (CBCT) to detect and measure isthmi in the apical root canals of mandibular molars by using micro-computed tomography (μ-CT) as the reference standard.Forty mandibular first molars selected on the basis of μ-CT scan and presenting isthmi in the apical 3-mm mesial roots were scanned by using the highest-resolution settings of a small-volume CBCT unit. Isthmi lengths were measured and compared between both μ-CT and CBCT images to study the accuracy of CBCT readings. Quantitative data for sensitivity rate were depicted as percentage value with 95% confidence interval. Results were analyzed by using linear regression between true lengths (μ-CT) and CBCT lengths, Bland-Altman plot and t test, at α = 0.05.CBCT sensitivity for isthmi detection was 65% (95% confidence interval, 0.4667-0.8333). An average of 74.7% of the lengths could be measured, and differences among the lengths in μ-CT and CBCT were significant (P .05; mean, 0.756 ± 0.655; t test), showing that there was no agreement between both methods.Accuracy of identifying apical isthmi of mandibular molars was highly influenced by the evaluation method. Small-volume CBCT imaging could not detect and measure apical isthmi length accurately. Moreover, using high-resolution settings in CBCT, it was not reliable to forecast the actual apical root canal anatomy.

The aim of this study was to evaluate some of the physicochemical properties of a new root canal sealer.The sealers tested were Sealer Plus compared with AH Plus. For the radiopacity, flow, solubility, and fabrication of test specimens relative to setting times, the American National Standards Institute/American Dental Association No. 57 (2000) and International Organization for Standardization 6876 (2012) specifications were followed. To measure the initial and final setting times, the ASTM C266/2008 standard was used. pH was evaluated in the time intervals of 3, 24, 72, and 168 hours. Statistical tests were applied to the results obtained at a level of significance of 5%.The results demonstrated that the Sealer Plus sealer showed a lower radiopacity value than AH Plus sealer (P .05); however, this was higher than the minimum value recommended by the specifications (ie, 3 mm Al). Relative to flow, the value for Sealer Plus was 19.19 mm and for AH Plus, 19.81 mm (P .05). Sealer Plus presented initial and final setting times of 138 minutes and 210 minutes, respectively, whereas the values for AH Plus were 437 minutes and 849 minutes, respectively (P .05). Relative to solubility, Sealer Plus presented 0.21% and AH Plus, 0.27% (P .05). None of the sealers showed a significant increase in pH (P .05).Sealer Plus sealer presented physicochemical properties in accordance with American National Standards Institute/American Dental Association (2000) No. 57 and International Organization for Standardization 6876 (2012) specifications.

Made available in DSpace on 2018-11-26T17:35:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-07-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Introduction: The aim of this study was to evaluate the cyclic and torsional fatigue resistance of the following reciprocating single-file systems: ProDesign R 25.06 (Easy Equipamentos Odontologicos, Belo Horizonte, Brazil), Reciproc R25 (VDW GmbH, Munich, Germany), and Unicone L25 (Medin SA, Nove Mesto in Morave, Czech Republic). Methods: Sixty instruments of the Pro Design R, Reciproc R25, and Unicone L25 systems (n = 20) were used. Cyclic fatigue resistance was tested measuring the time to failure in an artificial stainless steel canal with a 60 angle and a 5-mm radius of curvature (n = 10). Torque and angle of rotation at failure of new instruments (n = 10) in the 3 mm from the tip portion were measured during torsional testing according to ISO 3630-1. The fractured surface of each fragment was examined by scanning electron microscopy. Data were analyzed using 1-way analysis of variance and Tukey tests, and the level of significance was set at 5%. Results: The cyclic fatigue resistance values of ProDesign.R 25.06 were significantly higher than the other groups (P < .05). Reciproc R25 showed higher fatigue resistance than Unicone L25 (P < .05). In relation to the torsional test, the ProDesign R 25.06 and Unicone L25 systems showed higher angular rotation until fracture than Reciproc R25 (P