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The development of 3D-printed electrochemical sensors by fused deposition modeling (FDM) has been increasing exponentially in the last five years. In this context, commercial conductive filaments composed of a blend of carbon particles ( e.g. , graphene or carbon black (CB)) and insulating thermoplastic polymers ( e.g. , polylactic acid (PLA) or acrylonitrile butadiene styrene (ABS)) have been widely used for electrode fabrication. However, such materials may be expensive and the electrodes when used "as-printed" exhibit poor electrochemical performance as a function of the low content of conductive particles in the composition (∼10 to 20 wt%), which requires one or more post-treatment steps ( e.g. polishing, chemical, electrochemical, and photochemical) to reach good electrochemical performance. In this technical note a less used approach to produce "ready-to-use" electrochemical platforms based on 3D printing is explored, which consists of the coating of 3D-printed insulating substrates with homemade conductive composites. To demonstrate the potentiality of this alternative protocol, 3D-printed ABS insulating substrates at two geometries were coated in a highly loaded graphite (55 wt%) homemade composite (G-ABS) and evaluated for the detection of the ferri/ferrocyanide redox probe and model analytes in stationary and hydrodynamic 3D-printed systems (nitrite in micro-flow injection analysis/μFIA and paracetamol in batch injection analysis/BIA, respectively). The analytical parameters acquired with the coated electrodes were comparable to those obtained using conventional electrodes (glassy carbon, boron-doped diamond and carbon screen-printed) and 3D-printed sensors fabricated with commercial filaments. Moreover, the inclusion of carbon black in the fluid conductive composite was demonstrated as a perspective to obtain modified coated 3D-printed surfaces easily for the first time. This alternative "do it yourself" strategy is promising for the large-scale production of very cheap (US$ 0.08) and high-performance electrodes based on FDM 3D printing. Moreover, this approach dispenses the acquisition of commercial conductive filaments and the laborious development of homemade filaments.

Here, a novel electrically conductive thermoplastic material composed of graphite/acrylonitrile butadiene styrene (G/ABS) is reported for the first time. This material was explored on the production of 3D printing-based electrochemical sensors with enhanced sensitivity using a novel fabrication approach. The developed G/ABS electrodes showed lower charge transfer resistance (157 vs. 3279 Ω), higher electroactive area (0.61 vs. 0.19 cm 2 ) and peak currents ca. 69% higher when compared with electrodes fabricated using carbon black/polylactic acid (CB/PLA) commercial filament, which has been widely explored in recent literature. Moreover, the G/ABS sensor provided satisfactory repeatability, reproducibility and stability (relative standard deviations (RSDs) were 1.14%, 6.81% and 10.62%, respectively). This improved performance can be attributed to the fabrication protocol developed here, which allows the incorporation of greater amounts of conductive material in the polymeric matrix. The G/ABS electrode also required a simpler and quicker protocol for activation when compared to CB/PLA. As proof of concept, the G/ABS sensor was employed for electroanalytical quantification of paracetamol (PAR) in pharmaceutical products. The linear concentration range was observed from 0.20 to 30 μmol L -1 and the limit of detection achieved was 54 nmol L -1 , much lower than several recent studies dealing with the same analyte. The sensitivity of the G/ABS electrode regarding PAR was also far better when compared to CB/PLA sensor (0.50 μA/μmol L -1 vs. 0.12 μA/μmol L -1 ). Analyses in commercial pill samples showed good accuracy (recoveries ca. 108%) and precision (RSDs < 5%), suggesting great potential for use of this novel conductive thermoplastic in electroanalytical applications based on 3D printing., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Introduction: Periapical radiography (PR) is a diagnostic tool to be used by professionals in clinical practice. The method presents limitations, and doubts still exist about its value to evaluate furcation perforation and the reparative process of hard or soft tissues after treatment. Thus, the aim of this study was to evaluate the accuracy of PR as a diagnostic method to detect both resorption of the furcation area after induced experimental perforation and repair after perforation treatment using histopathological findings as a gold standard., Methods: Thirty teeth of beagle dogs with furcation perforation were filled with Biodentine (Septodont, Saint-Maur-des-Fossés, France), ProRoot White mineral trioxide aggregate (Dentsply Tulsa Dental Specialties, Tulsa, OK), or gutta-percha and examined using PR and histology. Sensitivity, specificity, predictive values, and accuracy were calculated., Results: PR detected repair and reabsorption of furcation perforation in 55% and 48% of the teeth, respectively. Histologic analysis showed furcation perforation in 66% and 21% of the teeth, respectively. Sensitivity and specificity of PR for the detection of repair were 0.84 and 1, respectively, whereas for resorption detection, the values were 0.43 and 0.65, respectively. Diagnostic accuracy for PR was 0.89 and 0.72 for repair and resorption of furcation perforation, respectively. PR showed more accurate diagnostic (true positives + true negatives/total) in repair detection compared with resorption of furcation perforation., Conclusions: We conclude that PR is not adequate in detecting resorption progress after the treatment of furcation perforation, and we encourage the use of digital imaging when suspicious of a possible unsuccessful result after furcation perforation treatment., (Copyright © 2020 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Aim: To evaluate the response of the apical and periapical tissues of dog teeth with apical periodontitis after one-session root canal treatment with and without antimicrobial photodynamic therapy (aPDT) compared with the use of an intracanal dressing., Methodology: Sixty root canals with an induced periapical lesion were instrumented and assigned to three groups: I, two-session root canal treatment using antibacterial dressing with calcium hydroxide-based paste; II, one-session root canal treatment using aPDT; and III, one-session root canal treatment in which the root canals were filled immediately after biomechanical preparation. The animals were euthanized after a 90-day experimental period. The maxillas and mandibles with teeth were submitted to histotechnical processing and haematoxylin-eosin staining. Descriptive microscopic analysis of the apical and periapical region characteristics was performed, as well as morphometric assessment of the periapical lesion areas in fluorescence microscopy. Quantitative data were analysed statistically by the nonparametric Kruskal-Wallis test and Dunn's post-test (α = 0.05)., Results: Group I was characterized by progressive repair, with the presence of fibres, cells and blood vessels. Group II had periodontal ligaments with the presence of collagen fibres and residual inflammatory cells. Group III had a dense inflammatory infiltrate with extensive oedematous areas and fibrillar dissociation, suggesting a persistent inflammatory and resorptive condition. Regarding periapical lesion size, group I had significantly smaller lesions (P < 0.05) than groups II and III, which did not differ significantly from each other., Conclusion: Two-session root canal treatment using a calcium hydroxide-based dressing was associated with significantly smaller periapical lesions at 90 days and characterized by progressive repair., (© 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

Objective: The aim of this study was to evaluate the oral manifestations of celiac disease (CD), the chemical composition of dental enamel, and the occurrence of CD in children with dental enamel defects (DEDs)., Study Design: In the study, 52 children with CD and 52 controls were examined for DEDs, recurrent aphthous stomatitis (RAS), dental caries experience, and salivary parameters. In addition, 10 exfoliated primary enamel molars from each group were analyzed by energy dispersive x-ray spectroscopy and Fourier transform infrared spectroscopy. Fifty children with DEDs were submitted to CD diagnosis., Results: Among the children with CD, a higher prevalence of DEDs (P = .00001) and RAS (P = .0052), lower caries experience (P = .0024), and reduction of salivary flow (P = .0060) were observed. Dental enamel from the children with CD demonstrated a lower calcium-to-phosphorus ratio (P = .0136), but no difference in the carbonate-to-phosphate ratio (P = .5862) was observed. In the multivariate analysis, CD was a protective factor for caries (OR = 0.74) and a risk factor for RAS (OR3.23)., Conclusions: The children with CD presented with more RAS, DEDs, reduction of salivary flow, and chemical alterations in the enamel., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Aim: To characterize the formation and progression of experimentally induced periapical lesions in teeth of MyD88 knockout (MyD88 KO) mice compared with wild-type (WT) mice., Methodology: Periapical lesions were induced in the mandibular first molars of 30 WT and 30 MyD88 KO mice. After 7, 21 and 42 days, the animals were euthanized and the mandibles were subjected to histotechnical processing. Histological sections were stained with haematoxylin and eosin (HE), TRAP histoenzymology, Brown and Brenn staining and immunohistochemistry (RANK, RANKL, OPG). Data were subjected to statistical analysis by the nonparametric Mann-Whitney and Kruskal-Wallis tests and the Dunn post-test, using the SPSS software, version 17.0 (α = 0.05)., Results: Regarding the periapical lesion size, the MyD88 KO group had significantly higher values than the WT group in the periods of 7 (P = 0.001) and 21 days (P = 0.05). A larger number of neutrophils in the MyD88 KO group were observed (P = 0.01 at 7 days, P = 0.004 at 21 days and P < 0.001 at 42 days). Regarding the number of osteoclasts, no statistically significant difference was observed between the groups at any of the experimental periods (P = 0.884 at 7 days, P = 0.506 at 21 days and P = 0.211 at 42 days)., Conclusions: In the absence of MyD88, the animals had larger periapical lesions, with a severe inflammatory infiltrate and a significantly larger number of neutrophils., (© 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

This case report describes the nonsurgical endodontic treatment and intentional replantation of a mandibular molar and its nearly 14-year follow-up. A 56-year-old woman sought treatment with complaint of discomfort and sensitivity in the mandibular left area. The radiographic examination showed that the mandibular left first molar was endodontically treated, with over-instrumentation of the distal root and unsatisfactory obturation on the mesial root. A large periapical lesion was observed surrounding the roots. In view of the patient's limited interocclusal space and objection to undergo an apical surgery, intentional replantation was suggested as an alternative. The patient returned for clinical and radiographic follow-up at 15 days, 40 days, 6 months, 12 months, and once yearly thereafter. At the last visit, after 14 years, no painful symptomatology was reported, probing depth was no greater than 3 mm, the periradicular area had normal appearance and no evidence of root resorption or periapical lesion.