Ex vivo evaluation of the influence of cervical preflaring on choice of apical reciprocating file.

The aim of this study was to evaluate the influence of cervical preflaring on the choice of reciprocating file size (Reciproc system) and the difficulty in reaching the working length for instrumentation of molar root canals. A total of 352 human molars were divided into 2 groups of 176 molars each. In the no preflaring (NPF) group, no cervical preflaring was performed. A reciprocating file (R25, R40, or R50) was selected, and instrumentation was performed in accordance with the manufacturer's recommendations. In the preflaring (PF) group, a file was selected, and cervical preflaring was performed with the use of No. 30/.10 or No. 25/.08 orifice shaper instruments. The clinician then selected a new reciprocating file or used the originally selected file to perform the instrumentation as done in the NPF group. Any changes in choice of file after preflaring were documented for the PF group, and the number of insertions required to reach the working length was recorded for both groups. After preflaring, the selected file was changed from R25 to R40 in 20.08% of canals, from R25 to R50 in 0.40% of canals, and from R40 to R50 in 42.14% of canals. After preflaring, 2.88% of the canals with an initial selection of an R50 file required an instrument with a larger diameter for effective preparation. There was a statistically significant difference between the groups for all file size changes (P < 0.001; χ² test). The mean numbers of instrument insertions needed for the NPF and PF groups, respectively, were 4.09 and 2.42 (R25); 3.49 and 2.31 (R40); and 2.70 and 1.81 (R50). There was a statistically significant difference between the groups for all file sizes (P < 0.001; Kruskal-Wallis test). Under the conditions of this study, preflaring enabled a more suitable selection of reciprocating instrument, which, in turn, allowed for fewer insertions of the file up to the working length.

Evaluation of foramen locating accuracy of an endodontic motor integrated with electronic foramen employing optimal glide path kinematics.

OBJECTIVE: This study aimed to evaluate the accuracy of the auto apical function in the maintenance of the apical limit of instrumentation during glide path procedures when associated to OGP kinematics of Tri Auto ZX2, compared to the continuous rotation of the same motor, as well as Root ZX II and VDW Gold. MATERIALS AND METHODS: Forty-eight extracted human mandibular single-rooted premolars were selected. After endodontic access, cervical pre-flaring was performed using size 30, 0.10 taper rotary instruments, and the apical foramen size was standardized to 200 µm. Teeth were randomly divided into four groups (n = 12) according to the device and kinematics. For all the groups, the Auto Apical Stop function (AAS) was set to the 0.0 mark. Glide path instruments size 25, .01 taper were activated inside the canals until the apical limit was reached. Then, the files were fixed with cyanoacrylate to the teeth and decoupled from the equipment. Data were statistically analyzed in GraphPad Prism 6.0 software with the significance set at 5% (Kruskal-Wallis tests). RESULTS: There was no difference in the mean deviation between the groups. No significant difference was found among the groups when the distributions and percentages of differences between the file tip and the apical foramen were compared (P > 0.05). CONCLUSION: The use of auto apical function at the 0.0 mark of all tested devices provided an adequate control of the apical limit during glide path preparation. Foramen locating accuracy of Tri Auto ZX2 in OGP kinematics was similar to those of Tri Auto ZX2, Root ZX II, and VDW Gold in continuous kinematics. CLINICAL RELEVANCE: Clinical strategies in canal negotiation and glide path as OGP motion associated to electronic foramen locators could reduce iatrogenic risk of deviation and file fractures and create an easier initial preparation to facilitate endodontic procedures.

Biological and antimicrobial properties of the association Ambroxol and a water-soluble viscous liquid as a vehicle for a tricalcium silicate-based sealer.

This study aimed to investigate the antimicrobial and biological properties of Ambroxol associated with glycerin (GLI), propylene glycol (PG), and polyethylene glycol (PEG) as a possible vehicle for an experimental tricalcium silicate sealer, with the intention of developing a new biomaterial. Mouse undifferentiated dental pulp cells (OD-21) were cultured, and the effects of different association on cell proliferation and inflammatory cytokine production were investigated. Antimicrobial adhesion of Enterococcus faecalis to setting sealers at 2 h was evaluated. Polyethylene tubes containing experimental sealers and empty tubes were implanted into dorsal connective tissues of 12 male 3- to 4-months-old Wistar rats (250-280 g). After 7 and 30 days, the tubes were removed and processed for histological and immunohistochemical analyses. ANOVA followed by Bonferroni correction and ANOVA followed by Tukey test was used for parametric data and Kruskal-Wallis followed by Dunn for nonparametric (p < 0.05). Cell proliferation was dose-dependent, since all association were cytotoxic at higher concentrations; however, Ambroxol-PEG showed significantly higher cytotoxicity than other association (p < 0.05). In addition, irrespective of the association, no cytokine production was observed in vitro. Ambroxol-GLI reduced bacterial viability, whereas Ambroxol-PEG increased (p < 0.05). Histological examination showed no significant difference in the inflammatory response (p > 0.05) and mineralization ability in all association. Additionally, IL-1ß and TNF-α were upregulated on Ambroxol-PEG in relation to Control at 07 days (p < 0.05). Ambroxol-GLI was the best vehicle for experimental tricalcium silicate sealer, as it promoted an increase in antimicrobial activity without altering the inflammatory response or mineralization ability.

Endodontic treatment of hypertaurodontic teeth with anatomical variations: case reports.

Taurodontism, usually associated with genetic disorders, is an anomaly in dental development in which the tooth presents with a vertically elongated pulp chamber due to an invagination failure of the Hertwig epithelial sheath. This article presents 2 case reports describing the endodontic treatment of permanent taurodontic molars in systemically healthy patients. In case 1, a maxillary left first molar presented with hypertaurodontism and 5 root canals. In case 2, a mandibular left second molar presented with hypertaurodontism and a C-shaped canal. Treatment of both teeth was based on careful radiographic evaluation with magnification, which allowed the root canal orifices to be identified and the endodontic treatment to be performed. Chemical-mechanical preparation was performed with mechanized instruments and a 2.5% sodium hypochlorite solution. As an auxiliary protocol to finish cleaning, passive ultrasonic irrigation was performed, and a thermoplastic filling technique was used. When complex internal anatomy and accessory root canals are present, endodontic treatment of a tooth presenting with hypertaurodontism can be challenging. Given the complexities of the present cases, the positive outcomes can be attributed to the use of magnification during endodontic procedures and meticulous attention to tooth preparation and obturation techniques.

Evaluation of Foraminal Enlargement with Thermally Treated Nickel-Titanium Systems.

AIM AND OBJECTIVE: To evaluate morphologic changes in the main foramen after enlargement with four different systems. MATERIALS AND METHODS: One hundred and twenty canals (buccal of maxillary molars and mesial of mandibular molars) with patency and apical foramen ≤200 µm were included. These apical foramina were photographed and then randomly divided into four experimental groups, according to the ProDesign Logic (PDL), ProDesign R (PDR), twisted file adaptive (TFA), and WaveOne Gold (WOG) systems, all of which were composed of three sequential instruments (Glidepath, #25 and #35). Root canals were prepared 1 mm beyond the main foramen (n = 30). The specimens were photographed again to capture intermediate (#25) and final enlargement (#35) images. These were analyzed using an image software that allowed comparison of the enlarged area and shape of the main foramen. RESULTS: In the Intragroup comparison, the Friedman's test showed a statistical difference between each phase of foramen enlargement (p <0.05). In the intergroup comparison, the percentage of foramen enlargement showed statistically significant difference between Groups PDR and TFA only in the analysis from #25 to #35, with 42.88 and 67.34% of foramen area widening, respectively. Relative to the final foramen shape, 81.7% were observed to be circular, 17.5% oval, and 0.8% flattened. CONCLUSION: Our results showed that foramen enlargement allowed an increase in area, maintained the circular shape of the foramen in the majority of cases, irrespective of the system used, and was a feasible option for use during preparation of the root canal system.

Oleaginous yeasts for sustainable lipid production-from biodiesel to surf boards, a wide range of "green" applications.

A growing world population and a growing number of applications for vegetable oils are generating an increasing demand for these oils, causing serious environmental problems. A sustainable lipid production is then fundamental to address these problems. Oleaginous yeasts are a promising solution for sustainable lipid production, but, with the current knowledge and technology, they are still not a serious alternative in the market. In this review, the potential of these yeasts is highlighted and a discussion is made mainly focused on the economics of the oleaginous yeast oil production and identification of the key points to be improved to achieve lower production costs and higher income. Three main stages of the production process, where costs are higher, were identified. To render economically feasible the production of oils using oleaginous yeasts, a reduction in production costs must occur in all stages, lipid yields and productivities must be improved, and production must be targeted to high-value product applications.

Influence of ultrasonic agitation on bond strength, marginal adaptation, and tooth discoloration provided by three coronary barrier endodontic materials.

OBJECTIVES: The effect of ultrasonic agitation (UA) on bond strength and adaptation of cervical plugs prepared with MTA Angelus (MTA), MTA Repair HP (MTAHP), and Biodentine (BIO) was evaluated. Dentin discoloration caused by the materials/treatment was also assessed. MATERIALS AND METHODS: Seventy-two single rooted teeth were divided into six groups depending on the materials/treatment. After cervical plug preparation, dentin discs were excised for the push-out test; additional discs were analyzed under the confocal microscope to determine adaptation (gaps occurrence). For dentin discoloration analysis (ΔE), blocks of bovine incisors had cavities prepared and filled with the materials/treatment (from 7 to 180 days). RESULTS: Both bond strength and adaptation were positively influenced by UA (P < 0.05). Comparison between materials showed an advantage for BIO when compared to MTAHP (P < 0.05). The best and worst results were provided by BIO/UA (12.66 MPa and 1.87%) and MTAHP (2.54 MPa and 28.58%), respectively. For ΔE, significant differences were observed throughout the periods. Just the MTA without UA exhibited noticeable discoloration at 180 days (P < 0.05). CONCLUSIONS: UA favored a better adaptation of the materials to the dentin root, resulting in higher bond strength and adaptation of the materials to the root canal walls. Moreover, UA reduced MTA discoloration, keeping it imperceptible over the period evaluated. CLINICAL RELEVANCE: The better adaptation and higher bond strength provided by UA can be considered clinically relevant due to the importance of maintaining blood clot integrity and the possible esthetic compromise provided by reparative materials when used as coronary barrier in regenerative procedures.

Fused tooth: clinical approach to endodontic treatment.

Tooth fusion, the union of 2 developing dental germs, can affect the primary and permanent dentitions as well as supernumerary teeth. The anatomy of fused teeth represents a challenge when endodontic treatment is needed. This case report describes the endodontic treatment performed in a permanent maxillary incisor fused to a supernumerary tooth. A 10-year-old girl was referred for endodontic treatment in her maxillary left central incisor, which displayed a wide and bifid crown. Periapical radiographs showed that the tooth had 2 crowns with fused roots; the pulp chambers of the crowns communicated with each other at the cervical third of the tooth. Local anesthetic was administered, and a rubber dam was used to isolate the tooth. The clinician then completed preparation of the access cavity and examined the root canals of the fused teeth. After chemical-mechanical instrumentation, the clinician obturated the root canals using Tagger's hybrid technique. The pulp chamber was sealed with glass ionomer cement, and the patient was referred for restorative treatment. Teeth with morphologic abnormalities must be treated with a multidisciplinary approach to ensure a better prognosis.

Durability of Two R-Phase Rotary Systems used in the Mechanical Instrumentation of Dilacerated Root Canals.

AIM: This study was aimed to analyze, through an ex vivo test, the durability of two rotary systems used in curved root canals of extracted molars. MATERIALS AND METHODS: At first, 150 upper and lower molars were selected, presenting curvature at least in one of the root canals. They underwent access cavity and radiographed with a # 15 file into the canal to determine their maximum curvatures, classified as schneider. The teeth with one or more curved canals were included in this study. Finally, 120 curved root canals were statistically divided into six sets of 20 curved canals. Two rotatory systems, K3 XF (RCS sequence) and twisted file (Large Kit), both treatment R-Phase, were analyzed. Three kits were used for each system, each one instrumented one of the six sets of 20 curved canals. File deformations were noted, and the files were used until a fracture occurs or until completion of 20 canals preparation. Fractured files before the end of the instrumentation of the 20 canals were replaced, continuing the full instrumentation set. Statistical analysis was performed by analysis of variance (ANOVA) (p >0.05), and a qualitative assessment was also made. RESULTS: It was found that there was no statistical difference between the K3 XF and TF systems regarding fracture. CONCLUSION: There were no statistical differences between the K3 XF systems in the RCS sequence and the twisted file kit Large system, as to the number of instrumented conduits to the deformation or fracture. CLINICAL SIGNIFICANCE: The findings of this study reinforce that, it is necessary to choose files that support curved roots preventing accidents inside the root canal. Therefore, it is important for professionals to have knowledge and command of these protocols to obtain more satisfactory results.

Evaluation of Influence of Widening Apical Preparation of Root Canals on Efficiency of Ethylenediaminetetraacetic Acid Agitation Protocols: Study by Scanning Electron Microscopy.

AIM: The purpose of this study was to evaluate the influence of widening the apical root canal preparation (RCP) on the efficiency of different ethylenediaminetetraacetic acid (EDTA) agitation protocols on smear layer removal: EDTA; EDTA + Easy Clean in rotary movement (ECROT); EDTA + Easy Clean in reciprocating movement (ECREC); and EDTA + Passive ultrasonic irrigation (PUI). MATERIALS AND METHODS: A total of 80 mandibular premolars had their crowns sectioned and then were divided into two groups according to widening: size 25 or 40, 0.08 taper. Sequentially they were once again allocated to subgroups according to the agitation protocol performing eight experimental groups (n = 10). Ten additional teeth were prepared for controls (C+/C-). The specimens were then submitted to the cleaning protocols and thereafter cleaved and microphotographed by variable pressure scanning electron microscopy (SEM) at previously determined points along their root thirds (750*). Scores were attributed to the images, and data were analyzed by the Kruskal-Wallis, Student-Newman-Keuls and Friedman tests. RESULTS: A higher widening was observed to have a positive influence on cleaning efficiency offering significant differences in global and apical third evaluations (p < 0.05). Relative to the agitation, significant differences were observed mainly in the apical third, with PUI and ECROT providing the best results (p < 0.05); no difference for C+ was observed when higher widening was employed. CONCLUSION: A greater widening of the apical third provided a significant improvement in the action of the agitation/activation protocols. Moreover, the PUI and ECROT activation methods were shown to be superior to the use of EDTA solely, particularly in the apical third. CLINICAL SIGNIFICANCE: The findings of this study reinforce the need for clinical use of additional methods to complement cleaning. Therefore, it is important for professionals to have knowledge and command of these protocols to obtain more satisfactory results.

Tau interactome mapping based identification of Otub1 as Tau deubiquitinase involved in accumulation of pathological Tau forms in vitro and in vivo.

Dysregulated proteostasis is a key feature of a variety of neurodegenerative disorders. In Alzheimer's disease (AD), progression of symptoms closely correlates with spatiotemporal progression of Tau aggregation, with "early" oligomeric Tau forms rather than mature neurofibrillary tangles (NFTs) considered to be pathogenetic culprits. The ubiquitin-proteasome system (UPS) controls degradation of soluble normal and abnormally folded cytosolic proteins. The UPS is affected in AD and is identified by genomewide association study (GWAS) as a risk pathway for AD. The UPS is determined by balanced regulation of ubiquitination and deubiquitination. In this work, we performed isobaric tags for relative and absolute quantitation (iTRAQ)-based Tau interactome mapping to gain unbiased insight into Tau pathophysiology and to identify novel Tau-directed therapeutic targets. Focusing on Tau deubiquitination, we here identify Otub1 as a Tau-deubiquitinating enzyme. Otub1 directly affected Lys48-linked Tau deubiquitination, impairing Tau degradation, dependent on its catalytically active cysteine, but independent of its noncanonical pathway modulated by its N-terminal domain in primary neurons. Otub1 strongly increased AT8-positive Tau and oligomeric Tau forms and increased Tau-seeded Tau aggregation in primary neurons. Finally, we demonstrated that expression of Otub1 but not its catalytically inactive form induced pathological Tau forms after 2 months in Tau transgenic mice in vivo, including AT8-positive Tau and oligomeric Tau forms. Taken together, we here identified Otub1 as a Tau deubiquitinase in vitro and in vivo, involved in formation of pathological Tau forms, including small soluble oligomeric forms. Otub1 and particularly Otub1 inhibitors, currently under development for cancer therapies, may therefore yield interesting novel therapeutic avenues for Tauopathies and AD.

Soil-vegetation relationships and community structure in a "terra-firme"-white-sand vegetation gradient in Viruá National Park, northern Amazon, Brazil.

Viruá National Park encompasses a vast and complex system of hydromorphic sandy soils covered largely by the white sand vegetation ("Campinarana") ecosystem. The purpose of this study was to investigate a vegetation gradient of "terra-firme"-white sand vegetation at the Viruá National Park. Nine plots representing three physiognomic units were installed for floristic and phytosociological surveys as well as to collect composite soil samples. The data were subjected to assessments of floristic diversity and similarity, phytosociological parameters and to statistical analyses, focused on principal components (PC) and canonical correspondence analysis (CCA). The vegetation of the Campinaranas types and Forest differed in biomass and species density. Ten species, endemic to Brazil, were particularly well-represented. PC and CCA indicated a clear distinction between the studied plots, based on measured soil variables, especially base sum and clay, which were the most differentiating properties between Campinarana and Forest; For the separation of the Campinarana types, the main distinguishing variable was organic matter content and cation exchange capacity. Higher similarity of Campinaranas was associated to a monodominant species and the lower similarity of Forest was related to the high occurrence of locally rare species.

Heterotypic seeding of Tau fibrillization by pre-aggregated Abeta provides potent seeds for prion-like seeding and propagation of Tau-pathology in vivo.

Genetic, clinical, histopathological and biomarker data strongly support Beta-amyloid (Aß) induced spreading of Tau-pathology beyond entorhinal cortex (EC), as a crucial process in conversion from preclinical cognitively normal to Alzheimer's Disease (AD), while the underlying mechanism remains unclear. In vivo preclinical models have reproducibly recapitulated Aß-induced Tau-pathology. Tau pathology was thereby also induced by aggregated Aß, in functionally connected brain areas, reminiscent of a prion-like seeding process. In this work we demonstrate, that pre-aggregated Aß can directly induce Tau fibrillization by cross-seeding, in a cell-free assay, comparable to that demonstrated before for alpha-synuclein and Tau. We furthermore demonstrate, in a well-characterized cellular Tau-aggregation assay that Aß-seeds cross-seeded Tau-pathology and strongly catalyzed pre-existing Tau-aggregation, reminiscent of the pathogenetic process in AD. Finally, we demonstrate that heterotypic seeded Tau by pre-aggregated Aß provides efficient seeds for induction and propagation of Tau-pathology in vivo. Prion-like, heterotypic seeding of Tau fibrillization by Aß, providing potent seeds for propagating Tau pathology in vivo, as demonstrated here, provides a compelling molecular mechanism for Aß-induced propagation of Tau-pathology, beyond regions with pre-existing Tau-pathology (entorhinal cortex/locus coeruleus). Cross-seeding along functional connections could thereby resolve the initial spatial dissociation between amyloid- and Tau-pathology, and preferential propagation of Tau-pathology in regions with pre-existing 'silent' Tau-pathology, by conversion of a 'silent' Tau pathology to a 'spreading' Tau-pathology, observed in AD.

Intracerebral injection of preformed synthetic tau fibrils initiates widespread tauopathy and neuronal loss in the brains of tau transgenic mice.

Neurofibrillary tangles composed of hyperphosphorylated fibrillized tau are found in numerous tauopathies including Alzheimer's disease. Increasing evidence suggests that tau pathology can be transmitted from cell-to-cell; however the mechanisms involved in the initiation of tau fibrillization and spreading of disease linked to progression of tau pathology are poorly understood. We show here that intracerebral injections of preformed synthetic tau fibrils into the hippocampus or frontal cortex of young tau transgenic mice expressing mutant human P301L tau induces tau hyperphosphorylation and aggregation around the site of injection, as well as a time-dependent propagation of tau pathology to interconnected brain areas distant from the injection site. Furthermore, we show that the tau pathology as a consequence of injection of tau preformed fibrils into the hippocampus induces selective loss of CA1 neurons. Together, our data confirm previous studies on the seeded induction and the spreading of tau pathology in a different tau transgenic mouse model and reveals neuronal loss associated with seeded tau pathology in tau transgenic mouse brain. These results further validate the utility of the tau seeding model in studying disease transmission, and provide a more complete in vivo tauopathy model with associated neurodegeneration which can be used to investigate the mechanisms involved in tau aggregation and spreading, as well as aid in the search for disease modifying treatments for Alzheimer's disease and related tauopathies.

Templated misfolding of Tau by prion-like seeding along neuronal connections impairs neuronal network function and associated behavioral outcomes in Tau transgenic mice.

Prion-like seeding and propagation of Tau-pathology have been demonstrated experimentally and may underlie the stereotyped progression of neurodegenerative Tauopathies. However, the involvement of templated misfolding of Tau in neuronal network dysfunction and behavioral outcomes remains to be explored in detail. Here we analyzed the repercussions of prion-like spreading of Tau-pathology via neuronal connections on neuronal network function in TauP301S transgenic mice. Spontaneous and GABA(A)R-antagonist-induced neuronal network activity were affected following templated Tau-misfolding using synthetic preformed Tau fibrils in cultured primary neurons. Electrophysiological analysis in organotypic hippocampal slices of Tau transgenic mice demonstrated impaired synaptic transmission and impaired long-term potentiation following Tau-seed induced Tau-aggregation. Intracerebral injection of Tau-seeds in TauP301S mice, caused prion-like spreading of Tau-pathology through functionally connected neuroanatomical pathways. Electrophysiological analysis revealed impaired synaptic plasticity in hippocampal CA1 region 6 months after Tau-seeding in entorhinal cortex (EC). Furthermore, templated Tau aggregation impaired cognitive function, measured in the object recognition test 6 months post-seeding. In contrast, Tau-seeding in basal ganglia and subsequent spreading through functionally connected neuronal networks involved in motor control, resulted in motoric deficits reflected in clasping and impaired inverted grid hanging, not significantly affected following Tau-seeding in EC. Immunostaining, biochemical and electron microscopic analysis in the different models suggested early pathological forms of Tau, including Tau-oligomers, rather than fully mature neurofibrillary tangles (NFTs) as culprits of neuronal dysfunction. We here demonstrate for the first time using in vitro, ex vivo and in vivo models, that prion-like spreading of Tau-misfolding by Tau seeds, along unique neuronal connections, causes neuronal network dysfunction and associated behavioral dysfunction. Our data highlight the potential relevance of this mechanism in the symptomatic progression in Tauopathies. We furthermore demonstrate that the initial site of Tau-seeding thereby determines the behavioral outcome, potentially underlying the observed heterogeneity in (familial) Tauopathies, including in TauP301 mutants.

Tauopathy contributes to synaptic and cognitive deficits in a murine model for Alzheimer's disease.

Tau alterations are now considered an executor of neuronal demise and cognitive dysfunction in Alzheimer's disease (AD). Mouse models combining amyloidosis and tauopathy and their parental counterparts are important tools to further investigate the interplay of abnormal amyloid-ß (Aß) and Tau species in pathogenesis, synaptic and neuronal dysfunction, and cognitive decline. Here, we crossed APP/PS1 mice with 5 early-onset familial AD mutations (5xFAD) and TauP301S (PS19) transgenic mice, denoted F(+)/T(+) mice, and phenotypically compared them to their respective parental strains, denoted F(+)/T(-) and F(-)/T(+) respectively, as controls. We found dramatically aggravated tauopathy (~10-fold) in F(+)/T(+) mice compared to the parental F(-)/T(+) mice. In contrast, amyloidosis was unaltered compared to the parental F(+)/T(-) mice. Tauopathy was invariably and very robustly aggravated in hippocampal and cortical brain regions. Most important, F(+)/T(+) displayed aggravated cognitive deficits in a hippocampus-dependent spatial navigation task, compared to the parental F(+)/T(-) strain, while parental F(-)/T(+) mice did not display cognitive impairment. Basal synaptic transmission was impaired in F(+)/T(+) mice compared to nontransgenic mice and the parental strains (≥40%). Finally, F(+)/T(+) mice displayed a significant hippocampal atrophy (~20%) compared to nontransgenic mice, in contrast to the parental strains. Our data indicate for the first time that pathological Aß species (or APP/PS1) induced changes in Tau contribute to cognitive deficits correlating with synaptic deficits and hippocampal atrophy in an AD model. Our data lend support to the amyloid cascade hypothesis with a role of pathological Aß species as initiator and pathological Tau species as executor.

Redox-Active Profile Characterization of Remirea maritima Extracts and Its Cytotoxic Effect in Mouse Fibroblasts (L929) and Melanoma (B16F10) Cells.

Remirea maritima is a tropical plant with a reticulated root system belonging to the family Cyperaceae, also known to have biologically active secondary metabolites. However, very few data on R. maritima's biological actions are available and there are no reports regarding the redox-active profile of this plant. In this study, we examined the total phenolic content of Remirea maritima hydroalcoholic (RMHA) extracts, redox properties against different reactive species generated in vitro and their cytotoxic effect against fibroblasts (L929) and melanoma (B16F10) cells. Total reactive antioxidant potential index (TRAP) and total antioxidant reactivity (TAR) results revealed that RMHA at all concentrations tested showed significant antioxidant capacity. RMHA was also effective against hydroxyl radical formation, reduction of Fe3+ to Fe2+ and in scavenging nitric oxide (NO) radicals. In vitro, the level of lipid peroxidation was reduced by RMHA extract and the data showed significant oxidative damage protection. The RMHA cytotoxicity was evaluated by a neutral red assay in fibroblast (L929) and melanome (B16F10) cells. The obtained results showed that the RMHA (40 and 80 µg/mL, respectively) reduced 70% of the viable cells. In conclusion, this study represents the first report regarding the antioxidant and anti-proliferative potential of R. maritima against B16F10 melanoma cells.

Influence of Different Apical Foramen Morphologies on the Accuracy of Four Electronic Foramen Locators.

OBJECTIVE: The aim of this study was to evaluate the accuracy of the Root ZX II (RZX), Raypex 6 (RAY), EPex Pro (EPEX), and CanalPro (CNP) electronic foramen locators (EFLs) in different foraminal morphologies (fully formed foramen, immature foramen with parallel walls, and immature foramen with divergent walls); this article also evaluated the influence of different penetration levels (0.0 mm and -1.0 mm). MATERIALS AND METHODS: Thirty single-rooted human premolars were accessed and had their cervical/middle thirds prepared with SX ProTaper files. The apical foramens (AF) were standardized to 250 µm and the initial root canal length (RCL1) was measured under 16x magnification with aid of a digital caliper. Using the alginate model, electronic measurements (EM) were taken 1.0 mm up to AF (EM1/-1) and at AF (EM1/0), always using adjusted hand K-files. The root apexes were then cross-sectioned 3.0 mm from the foramen; then, new RCL (RCL2) and electronic measurements were performed (EM2/-1 and EM2/0.0). Finally, retropreparations were performed with instruments SX ProTaper files introduced 4.0 mm in the apicocervical direction. Then new RCL (RCL3) and electronic measurements (EM3/-1 and EM3/0) were performed. STATISTICAL ANALYSIS: Values were tabulated and tested for normality using the Shapiro-Wilk test, which yielded nonparametric distributions of the data. Data were subjected to the Kruskal-Wallis and Dunn tests to estimate possible differences between devices as a function of foramen morphology and/or apical limit. The significance level was set at 5.0%. RESULTS: In general, the EFLs were accurate in determining the RCL. Statistically significant differences were observed between EPEX and RAY at 0.0, when measuring the divergent AF canals (p < 0.05). Regarding the different foramen morphologies in each EFL, RZX and EPEX showed no interference (p > 0.05), whereas RAY and CNP had lower accuracy levels at 0.0 with divergent AF (p < 0.05). CONCLUSION: The four devices evaluated are accurate to determine the RCL in the conditions tested. The apical limit of penetration did not have significant influence on their accuracy. Conversely, the presence of divergence in the AF walls negatively influenced de RAY and CNP precisions at the foraminal level.

Does the mixing method of AH Plus Jet affect its physicochemical and mechanical properties?

INTRODUCTION: The purpose of this study was to evaluate whether the mixing method of AH Plus Jet sealer affects its physicochemical and mechanical properties. METHODS: The properties of AH Plus Jet sealer were analyzed when mixed using either the Auto Mix Tip or manual mixing. The evaluated properties included radiopacity (n=5), initial and final setting times (n=5), flow (n=5), and solubility (n=3), following specifications outlined in ISO 6876/2012 and ADA Nº 57/2000. pH levels were measured at intervals of 3, 24, 72, and 168 hours (n=10). The push-out bond strength test was conducted using a universal testing machine and using bovine teeth (n=30). Failure modes were analyzed with stereomicroscopy. Porosity was evaluated under micro-CT (n=5) and scanning electron microscopy was also performed (n=5). One-way analysis of variance and Tukey, unpaired t-tests, or Mann-Whitney tests were used with a significance level of 5%. RESULTS: The Auto Mix exhibited a radiopacity value of 12.11 mmAl, whereas manual mixing resulted in 12.55 mmAl (P>0.05). For initial and final setting times, Auto Mix showed 901 minutes and 1779 minutes, respectively, while manual mixing recorded values of 631 minutes and 1504 minutes (P<0.05). In terms of flow, Auto Mix demonstrated higher values (25.26 mm) than manual mixing (21.71 mm) (P<0.05). No statistical differences were observed between the two methods for solubility and pH (P>0.05). Manual mixing presented a higher bond strength value (14.52 MPa) than Auto Mix (9.81 MPa) (P<0.05). The mixed failure mode was the most frequent outcome for both methods. The highest porosity was observed for Auto Mix (P<0.05). Scanning electron microscopy analysis revealed that manual mixing resulted in a smoother surface with fewer pores and smaller, more evenly distributed agglomerates compared to automatic mixing. CONCLUSION: The mixing method employed for AH Plus Jet sealer influences some physicochemical and mechanical properties of the material.

New Ultrasonic Tip for Root Canal Filling of the Mesial Canals of Mandibular Molars with Isthmus: A Laboratory Evaluation Using Computed Microtomography.

INTRODUCTION: The obturation quality of the mandibular molar mesial canals and isthmuses with two thermoplastic techniques, ultrasonic vertical condensation (UVC) and continuous wave of condensation (CWC), was evaluated using computed microtomography (µCT). METHODS: Thirty-six human mandibular molars had been previously scanned and analyzed using µCT for mesial roots with morphologically similar isthmuses for this study. Coronal access and confirmation of foraminal patency were performed, and the actual length of the teeth was established using a clinical microscope (40X magnification). The canals were prepared using ProTaper Gold instruments up to #F3, with 2.5% sodium hypochlorite as the irrigant solution, followed by a passive ultrasonic irrigation protocol. The specimens were randomly divided into the UVC and CWC groups based on the obturation technique to be used. Obturation was performed with #F3 gutta-percha cones cemented using AH Plus Jet sealer. The µCT scans were performed after 15 days, and the images were evaluated by a calibrated examiner blinded to the experimental groups to determine the filling rate of the entire canal area, including the main canal and isthmus. Student's t-test was used for statistical analysis; P values ≤0.05 were considered significant. RESULTS: Neither of the thermoplastic obturation techniques achieved complete filling of the canals (86.3% for UVC and 91.4% for CWC), with a statistically significant difference between them (P = .029). CONCLUSIONS: Under the conditions of the study, it can be concluded that none of the techniques completely filled the canal/isthmus of the mandibular molars; however, the CWC exhibited better performance.