Aim To evaluate possible modifications in root canal sealers subjected to a variety of heating conditions using vibrational spectroscopy and analysis of physical and chemical properties. Methodology EndoSequence BC Sealer HiFlow, Bio‐C Sealer, BioRoot RCS and AH Plus were analysed chemically using Raman spectroscopy (25–220 °C) and Fourier‐transform infrared spectroscopy (FT‐IR) (37–100 °C ). For FT‐IR, the materials were tested individually and mixed with root dentine powder. Scanning electron microscopy (SEM) and coupled energy dispersive spectroscopy (EDS) were used to evaluate surface and chemical elements. ISO 6876‐2012 and ASTM‐C266‐07 specifications were followed to evaluate flow, setting time (moist and dry), solubility and radiopacity. Also, pH analysis at 37 and 100 °C was performed. Shapiro–Wilk and Mixed ANOVA (within and between the effects of the subjects), Levene, and a post hoc analyses with Bonferroni correction were performed (P < 0.05). Results Vibrational spectroscopy revealed peaks of tricalcium silicate, dicalcium silicate and zirconium dioxide. Chemical changes in the Raman spectra during heating were discrete, as the inorganic content predominated the signalling for all root canal sealers. FT‐IR analysis exhibited spectral changes in water absorption for EndoSequence BC Sealer HiFlow and Bio‐C Sealer, probably related to dehydration. For BioRoot RCS and AH Plus, no significant chemical changes were observed. Bio‐C Sealer exhibited a band of polyethylene glycol only after heating to 100 °C, probably related to its thermal decomposition. SEM/EDS analysis corroborated the composition results observed in vibrational spectroscopy for all materials. Heating to 100 °C significantly changed the flowability of all calcium silicate‐based sealers with a wide variation in setting times at both temperatures, along with solubility levels above ISO standards. For all tested sealers, radiopacity fulfilled the requirements, and pH exhibited alkaline values. Conclusions The tested calcium silicate‐based sealers were affected by heating. Calcium silicate‐based root canal sealers had high solubility which is a concern for their clinical use. AH Plus was the only root canal sealer that was stable after heating.

Endodontic biomaterials have significantly improved dental treatment techniques in several aspects now that they can be used for vital pulp treatments, as temporary intracanal medication, in definitive fillings, in apical surgeries, and for regenerative procedures. Calcium silicate-based cement is a class of dental material that is used in endodontics in direct contact with the dental structures, connective tissue, and bone. Because the material interacts with biological tissues and stimulates biomineralization processes, its properties are of major importance. The main challenge in endodontic treatments is the elimination of biofilms that are present in the root canal system anatomical complexities, as it remains even after chemical-mechanical preparation and disinfection procedures. Thus, an additional challenge for these biomaterials is to exert antimicrobial activity while maintaining their biological properties in parallel. This article reviews the literature for studies considering the antimicrobial properties of calcium silicate-based dental biomaterials used in endodontic practice. Considering the reviewed studies, it can be affirmed that the reduced antimicrobial effect exhibited by calcium silicate-based endodontic materials clearly emphasizes that all clinical procedures prior to their use must be carefully performed. Future studies for the evaluation of these materials, and especially newly proposed materials, under poly-microbial biofilms associated with endodontic diseases will be necessary.

Calcium silicate-based root canal sealers have been developed in powder/liquid or premixed ready-to-use forms. The evaluation of the physico-chemical properties of a prototype powder/liquid MTApex Sealer (Ultradent) in comparison to a ready-to-use material EndoSequence BC Sealer (Brasseler) was performed. The paste/paste epoxy resin-based AH Plus (Dentsply) served as control for comparisons. The sealers were evaluated (n = 6) regarding setting time (in dry and moist environments), flow and radiopacity, following the ISO-6876/2012 standard. Also, the pH was assessed. Material’s surface and chemical characterization was evaluated using scanning-electron-microscopy (SEM) and energy-dispersive-spectrometry (EDS). Mixed ANOVA, Shapiro-Wilk, Levene, and post-hoc analysis with Bonferroni correction were performed at a significance level of 5%. MTApex Sealer exhibited the highest flow and EndoSequence BC Sealer had a significantly longer setting time in dry compared to the moist environment; however, for MTApex Sealer and AH Plus no significant changes occurred when additional moisture was provided. All materials exceeded 7 mm Al of radiopacity and showed a decreasing alkalinity over the 21 day-analysis. SEM/EDS evaluation resulted in peaks of calcium, silicon, and the respective radiopacifier. The prototype powder/liquid MTApex Sealer had the highest flow and similar setting time in both dry and moist environments; opposingly, EndoSequence BC Sealer was crucially influenced by external moisture. This suggests that the powder/liquid materials’ setting seems to be more predictable.

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Objective: Evaluate the cytotoxicity in human osteoblastic cells and antimicrobial activity in different root canal sealers in vitro. Methods: BioRoot RCS, TotalFill BC Sealer, and Bio-C Sealer were used in experimental groups, and AH Plus was used as a control. Human osteoblast-like cells and MTT quantitative colorimetric assay were used to evaluate cytotoxicity. Saos-2 cells were exposed to undiluted sealer extracts for 24 h. The supernatant was then collected and the formazan crystals resulting from MTT reduction were dissolved in pure dimethyl sulfoxide. Absorbance was measured in an automated spectrophotometer at a wavelength of 540 nm. Antimicrobial activity was analyzed by the direct contact test using a polymicrobial biofilm composed of Enterococcus faecalis, Candida albicans, and Streptococcus mutans. At 24, 48, and 72 h, colony-forming units were counted on agar plates. A nonparametric Kruskal-Wallis test was used for the statistical analysis. The level of significance was set at 5%. Results: AH Plus showed the lowest cytotoxicity after 24 h, with a significant difference in relation to BioRoot RCS and Bio-C Sealer (p ≤ 0.01). There was no significant difference in cytotoxicity between TotalFill BC Sealer and Bio-C Sealer (p > 0.05). At 24 h, TotalFill BC Sealer and AH Plus showed the least microbial growth compared to Bio-C Sealer (p < 0.05). At 48 and 72 h, there were no significant differences between sealers (p > 0.05). Conclusions: AH Plus had the lowest cytotoxicity. TotalFill BC Sealer and AH Plus yielded greater reductions in microbial counts in the first 24 h compared to Bio-C Sealer. Clinical Relevance: 2c.

Calcium silicate-based materials are used to block the communication between the root canal and the periodontal ligament space. This brings the materials into contact with tissues and the potential for local and systemic elemental release and movement. The aim of the study was to evaluate the elemental release of bismuth from ProRoot MTA in contact with connective tissues after 30 and 180 days as well as any accumulation in peripheral organs using an animal model. Tricalcium silicate and hydroxyapatite containing 20% bismuth oxide (HAp-Bi) were used as controls. The null hypothesis was that bismuth migrates from tricalcium silicate-based materials when associated with silicon. The materials were examined using scanning electron microscopy, energy dispersive spectroscopy (SEM/EDS) and X-ray diffraction prior to implantation as well as using SEM/EDS, micro X-ray fluorescence and Raman spectroscopy after implantation to assess elemental presence in surrounding tissues. Histological analysis was used to evaluate the changes in tissue architecture and inductively coupled plasma mass spectrometry (ICP-MS) was used to investigate the elemental deposition. For the systemic investigation, routine blood analysis was performed and organs were obtained to evaluate the presence of bismuth and silicon using ICP-MS after acid digestion. In the histological analysis of the implantation sites, macrophages and multinucleated giant cells could be observed after 30 days which after 180 days became a chronic infiltrate; although, no major differences were identified in red and white blood cell analyses and biochemical tests. Implantation altered the materials as observed in the Raman analysis and bismuth was detected both locally and within kidney samples after both periods of analysis, indicating the potential for accumulation of bismuth in this organ. Smaller amounts of bismuth than observed in the kidney were also detected in blood, liver and brain for the ProRoot MTA and HAp-Bi after 180 days. Bismuth was released from the ProRoot MTA locally and was detected systemically and in samples without silicon; thus, the null hypothesis was rejected. The bismuth release demonstrated that this element accumulated both locally and systemically, mainly in the kidneys in comparison with brain and liver regardless of the material base.

Objective: Reuse of endodontic files remains an open issue in clinical practice. This study was designed to evaluate the fracture strength of WaveOne Gold (Dentsply Maillefer, Ballaigues, Switzerland) and Reciproc Blue (VDW, Munich, Germany) files with successive reuse for root canal shaping in up to three molars. Material and Methods: Prospective clinical study carried out by five calibrated endodontists who treated 384 molars (1291 canals) with a curvature <45° over a 12-month period. A total of 128 instruments were used (64 Reciproc Blue and 64 WaveOne Gold). Each instrument was used to treat three posterior teeth. After each use, the instruments were observed under an operating microscope at 8× magnification. Data were tabulated and a chi-square test was applied. Significance was accepted at the 5% level.  Results: Two instruments (one from each group) separated, both on the third use and during instrumentation of a mandibular first molar. In other words, instrument separation occurred in 0.52% of teeth and 0.16% of treated root canals.  Conclusions: There was a low incidence of instrument fracture when reciprocating files were used for up to three endodontic treatments in molars.

The effects of bismuth toxicity on the kidney—the main organ responsible for blood filtration—were systematically reviewed. This review was motivated by availability of several sources of bismuth in contact with humans including environmental, medications, dental materials, and cosmetics, potentially leading to kidney filtration of this chemical. No previous studies have systematically reviewed the literature considering this association. A total of 22 studies with a total of 46 individuals met the inclusion criteria, 19 being case reports with only one patient enrolled. The included studies publication dates ranged from 1961 to 2021 and the countries of publication were the United States of America, United Kingdom, Germany, Turkey, Switzerland, and Canada. Bismuth sources affecting the kidneys were uniquely reported as from medical purposes and mostly associated to overdoses with several symptoms, apparently with dose-dependent consequences. Patient history of renal impairment seemed to affect the outcome of the case. Several therapies were conducted following bismuth intoxication, and few studies performed renal biopsies describing its histological findings. It is crucial to reconsider the nephrotoxicity of bismuth compounds, mainly in patients with previous history of renal impairment.