This literature review has critically analyzed the published research related to the biomechanical preparation of root canals with three-dimensional analysis using micro-computed tomography (micro-CT). In December 2017, six databases (PubMed, Cochrane, Web of Science, Embase, Scopus, and Science Direct) were accessed using keywords to find articles including the use of the micro-CT analysis in biomechanical root canal preparation. There were 60 full articles that were selected, which were screened and read by two authors. The research that was reviewed and analyzed included root canal anatomy and sample selection, changes in canal shape and untouched canal areas, canal transportation and centering ability, and kinematics (motion). Of the studies selected, 49.18% discussed anatomical characteristics, with 54.1% of these studies describing mesial roots of mandibular molars with moderate curvature. Only 35% used a stratified distribution based on root canal system morphology and quantitative data obtained by micro-CT. The analysis of canal transportation and centering ability showed that transport values in the apical third exceeded the critical limit of 0.3 mm in mesial roots of mandibular molars with moderate curvature, especially in the groups in which a reciprocating system was used. In relation to kinematics, 91.70% of the reviewed studies evaluated continuous rotating instruments, followed by reciprocating rotation (38.33%), vibratory (15%), and the adaptive kinematics, which was in only 8.33%. The reciprocating kinematics was associated with higher canal decentralization and transportation indexes, as well as a greater capacity for dentin removal and debris accumulation. This literature review showed that the anatomy, the type of design and kinematics of instruments, and the experimental design are factors that directly influence the quality of biomechanical preparation of root canals analyzed in a qualitative and quantitative manner by micro-CT.

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For CAC with the lower CaCl content, the use of Bi O was detrimental for osteoblastic cell survival and differentiation compared to ZnO, while CAC with the higher CaCl content supported the acquisition of the osteogenic cell phenotype in vitro regardless of the radiopacifier used. Thus, CAC with 10% CaCl would potentially promote bone repair in the context of endodontic therapies.

Purpose. To evaluate the influence of ultrasonic activation on the physicochemical properties of setting time (ST), flow (FL), dimensional change (DC), and solubility (SL) of the cements: MTA, MTA Repair HP, and Biodentine®. Materials and Methods. Two experimental groups were formed according to the cement activation protocol: without ultrasonic activation and with ultrasonic activation. Cements were manipulated according to the manufacturers’ instructions. Ultrasonic activation group was performed with an E1 insert at power 3 (24–32 kHz) for 30 s directly in the center of the cement mass. The molds for analysis of the physicochemical properties were filled out and evaluated according to specification No. 57 from ANSI/ADA. The results were analyzed using the ANOVA test (two-way), complemented by Tukey’s test (α = 0.05). The distilled water used during the solubility test was submitted to spectrometry to verify the release of calcium ions. The morphologies of the external surface and the cross-section of the samples were analyzed by means of a scanning electron microscope (SEM). Results. For the ST, ultrasonic activation reduced the values of MTA, MTA Repair HP, and Biodentine ( P < 0.05 ). For the FL, ultrasonic activation did not alter the flow of MTA ( P > 0.05 ); however, it increased the flow MTA Repair HP and Biodentine ( P < 0.05 ). For the DC, the percentage values of dimensional change were higher when there was ultrasonic activation in all repair cements ( P < 0.05 ). For SL, there was a reduction in the percentage of the values in MTA and MTA Repair HP ( P < 0.05 ); however, there was no change in the values of Biodentine ( P > 0.05 ). Ultrasonic activation favored the release of calcium ions from all cements. The SEM analysis showed, in general, that the ultrasonic activation reduced and altered the particle shape of the cement. Conclusions. The ultrasonic activation interfered in the ST, DC, FL, ultrastructural morphology, and calcium release of the repair cements. However, it did not affect the solubility of Biodentine®.

The aim of this study was to evaluate the effects of proanthocyanidin (PA) and chlorhexidine (CHX) on the bond strength (BS), failure pattern, and resin-dentin interface morphology of the endodontic sealers EndoREZ and AH Plus after 24 h and 6 months of water storage. A total of 120 prepared bovine roots were divided into six groups: AH Plus, CHX+AH Plus, PA+AH Plus, EndoREZ, CHX+EndoREZ, and PA+EndoREZ. Dentin was treated for 1 or 5 min with 2% CHX or 15% PA, respectively. Roots were filled and stored in water for 24 h or 6 months (n = 10). Root slices were subjected to push-out test and scanning electron microscopy (SEM). Data were compared using two-way ANOVA and student's t-test (α = 5%). BS decreased over time for AH Plus and untreated EndoREZ (p < 0.05). At 24 h, AH Plus had higher BS than EndoREZ (p < 0.001), with no differences among treatments for both sealers (p > 0.05). At 6 months, EndoREZ had higher BS values for CHX and PA than control (p < 0.05). AH Plus had higher BS than EndoREZ (p < 0.001), while with CHX or PA, similar BS was observed in both sealers (p > 0.05). Cohesive and mixed failures were observed in all groups. SEM revealed sealer tags in the root dentin. In conclusion, BS decreased with time and AH Plus had higher BS than EndoREZ in untreated dentin; however, CHX or PA enhanced long-term BS of EndoREZ. Overall, dentin treatment affected failure pattern and resin-dentin interface morphology, particularly for EndoREZ.

The color change of teeth is frequent in the dental office and has important role in smile harmony. Objective: To discuss through case report the dental bleaching technique associated with enamel microabrasion to remove localized white spots on the maxillary incisors and canines. Case report: Patient, female, aged 18 years, attended the Clinic of the University of Ribeirão Preto complaining about the negative aesthetics of her smile due to the presence of white spots on teeth #13, #12, #11, #21, #22 and #23. After detailed anamnesis and clinical examination, the spots were diagnosed as enamel demineralization caused by cariogenic challenge occurred during the use of orthodontic brackets. Dental bleaching technique with 38% hydrogen peroxide was applied followed by enamel microabrasion with 6.6% hydrochloric acid and silicon carbide paste. After absolute isolation, 1 mm thick paste was applied on enamel stain with the aid of resin composite polishing abrasive rubber. Each application was followed by copious washing and analysis of the stain removal with wet enamel surface. In total, six applications of 10 seconds each were used. Finally, enamel polishing was executed with felt discs and diamond paste, and topical application of fluoride. Conclusion: It was concluded that bleaching associated with enamel microabrasion technique is a safe, simple, and effective option for solving the esthetics of teeth with white spots.

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