Main Cone Research Articles

Structural Control at Monte Somma and Vesuvio during the Last 5600 Years through Time and Space Distribution of Volcanic Vents

Vesuvio is likely the most if not one of the most dangerous volcanoes in the world. It is an active volcano, quiescent since 1944. The activity of the Monte Somma and Vesuvio volcanic complex is commonly referred to as two central volcanic edifices, namely Monte Somma and Vesuvio. Nevertheless, the opening of numerous eruptive fissures and related vents have characterized Monte Somma and Vesuvio throughout their lives. Spatter cones, spatter ramparts, and related eruptive fissures are disseminated downslope of Vesuvio’s main cone and on the southern slopes of the volcano. Similarly, cinder cones, spatter cones, and welded spatters are distributed in the sequence cropping out on the Monte Somma cliff and on the northern slopes of Monte Somma. In this work, a total of 168 eruptive vents have been identified and characterized in a GIS environment in which field data have been merged with relevant information from historical maps and documents. These vents have been arranged into units bounded by unconformities (Unconformity Bounded Stratigraphic Units) defining the eruptive history of the volcano. Alignments of vents and eruptive fissures within each unit have been compared with regional tectonic elements and the volcano-tectonic features affecting Monte Somma and Vesuvio during the last 5600 years, thus inferring that different structural trends were active in the different stratigraphic units. In particular, we show that the N300°–320° regional, Apennine, left-lateral, strike-slip fault system, the N040°–055° Torre del Greco direct fault system, the N70° and the EW fault system, and the generally NS oriented group of local brittle elements, all analyzed here, were differently active during the investigated time span. These tectonic trends might control the position of the eruptive fissures and vents in case of future unrest of the volcano.

A Comparative Evaluation of Push-Out Bond Strength of Six Different Root Canal Sealers: An In-Vitro Study.

Adhesiveness with radicular dentin is absent with gutta-percha, leading to microleakage and hence re-infection. Root canal sealer helps to achieve an adhesive interface between gutta-percha and root dentin thereby resisting the displacement forces during the functioning of teeth which is evaluated by the push-out test. The aim of this study is to compare the push-out bond strength and to assess the relative bond failure between dentin-sealer, sealer-main cone of (1) epoxy resin, (2) silicon, (3) mineral trioxide aggregate (MTA), (4) calcium hydroxide, (5) bioceramic, (6) zinc oxide eugenol containing root canal sealers. Sixty human permanent lower premolars with one root were collected, disinfected, and decoronated at cemento-enamel junction. Instrumentation was done with a K3 40,0.06 Ni-Ti rotary file and obturated using the main cone and sealer. Based on the sealer utilized, six groups were created: Group 1: AH-Plus, Group 2: RoekoSeal, Group 3: MTA Fillapex, Group 4: Apexit, Group 5: Smart Paste Bio, and Group 6: Procosol. One slice each was obtained from the coronal, middle, and apicalsections of all the obturated canals. Push-out bond strength and failure modes were studied. Statistics involved analysis of variance (ANOVA) followed by the post hoc Tukey test. All three sections exhibited the highest strength for Smart Paste Bio sealer and the least was for RoekoSeal. With all the sealers, the apical section had the highest strength followed by the middle and coronal. The smart seal system was superior to all other sealers and displayed a good bond to dentin.

Greek Fir Seeds and Cones as Underestimated Source of Essential Oil: Composition and Biological Properties

Greek fir (Abies cephalonica) seeds and cone scales were used, for the first time, for an analysis of their biologically active volatile compounds. It was observed that the yield of seed essential oil was 18%, which, among plants, is impressive. The seed essential oil was characterized by a distinctive forest scent with a subtle lemon undertone. The determination of the chemical compositions of the hydrodistilled oils isolated from the seeds and cone scales, achieved via chromatographic and spectroscopic methods (MS, NMR), revealed more than 100 compounds, mostly monoterpene hydrocarbons. The above methods allowed for the identification of 99.4% and 98.3% of the total seed and cone scale oil compositions, respectively. Limonene in its enantiomeric levorotatory form (S) constituted over 80% of the essential oil isolated from the Abies cephalonica seeds. This abundance of limonene makes them a potential natural source for obtaining this compound, which has demonstrated various biological properties. The main cone essential oil compounds were α- and β-pinenes as well as limonene. The cytotoxic effects of both essential oils were analyzed using the MTT assay in skin fibroblasts, keratinocytes, and melanoma cell lines, in the range of 0.012–0.2 μL/mL of essential oil. The cone scale essential oil was slightly more cytotoxic and induced a decrease in the cell viability in concentrations of 0.05–0.1 μL/mL, with small differences between the cell lines. The tested essential oils did not have selective effects on the melanoma cells (A375 and C32) when compared with normal cells. Both the seed and cone scale essential oils revealed good antimicrobial effects on Staphylococcus aureus and Escherichia coli.

Effect of using calcium-silicate and silicone based root canal sealers in bulk or with main core material on bond strength.

The purpose of this study was to assess the push-out bond strength of calcium-silicate and silicone based root canal sealers in bulk and with main cone. Roots (n=48) randomly divided into 4 groups (n=12) according to the obturation protocol; (1) iRoot SP in bulk; (2) iRoot SP with gutta-percha; (3) GuttaFlow Bioseal in bulk; (4) GuttaFlow Bioseal with gutta-percha. Six horizontal sections were obtained from each root (n=72). Effect of sealers on bond strength was statistically significant (P<0.05). Highest mean value was obtained in iRoot-Bulk group and lowest in GuttaFlow Bioseal-GP group. Both iRoot SP groups had significantly higher bond strength values than both GuttaFlow Bioseal groups (P<0.05). There was no significant difference between iRoot-GP and iRoot-Bulk groups (P=0.603) also GuttaFlow Bioseal-GP and GuttaFlow Bioseal-Bulk groups (P=0.684). Based on findings, using calcium silicate-based sealer in bulk can be also suitable in clinical practice.

Investigation on the Anisotropic Wetting Properties of Water Droplets on Bio-Inspired Groove Structures Fabricated by 3D Printing and Surface Modifications.

The self-driving structure to orientate the water movement has attracted considerable attention. Inspired by the wedgelike structures of biological materials in nature, such as spider silks and cactus spines, anisotropic spreading can be realized by combining Laplace pressure gradient and hydrophilic surface. In this study, a series of groove patterns were fabricated by a combination of 3D printing and surface modification. PLA pattern was modified by the atmospheric pressure plasma, followed by grafting with hydrolyzed APTES. This work reports the anisotropic transport of water droplets on a series of designed dart-shaped groove patterns with specific angles in the main arrow and tail regions. This structure can induce capillary force to regulate droplets from the main cone to two wedgelike, whereas the droplets are hindered toward the opposite side is oat the vicinity of the groove's tail. By means of the experiment, the mechanism of water transport in this pattern was revealed. This study can contribute a potential approach to manipulate and apply anisotropic wetting in many fields.

Morphometric Analysis of Mount Ararat (Eastern Anatolia, Türkiye)

In this study, the morphometric characteristics of Mount Ararat which is a strato-volcano are analyzed. Türkiye’s highest Mountain, Mount Ararat, is located in Eastern Anatolia. The Mountain takes the shape of two major volcanic cones after 2500 m height; these volcanic cones are named Greater Mount Ararat (5137 m) and Little Mount Ararat (3896 m). In this study, relief morphometry, basin morphometry, and drainage characteristics are morphometrically analyzed with Geographic Information Systems (GIS) using 10x10 m resolution Digital Elevation Model (DEM). According to the analysis results, there is an increase in the elevation on the high and steep slopes of the main cone and the slope values increase up to 56° in some locations towards the summit. On the other hand, according to the aspect analyses, 19.9% of slope faces are north-east direction, 14.7% of the slopes are north-direction, 9.4% are northwest, 9.8% are west, 10.7% are southeast, and 16.4% of the slopes are east direction. These results support the fact that Mount Ararat extends in NW-SE direction and is formed on the basis of a fault line in this direction. According to the grouping made by the altitude ranges analysis, the decrease in the rate of elevation belts starting from the slopes of the mountain towards the top confirms the structure of volcanic cone. Elevation differences in relative relief analyses range between 0 and 1141 m and this value increases to 1141 m on the slopes surrounding the summit. The cone structure of Mount Ararat was prominent in transverse and longitudinal profile analyses.

Mid-Holocene lateral collapse of Antuco volcano (Chile): debris avalanche deposit features, emplacement dynamics, and impacts

Antuco (37.4°S, 71.4°W; Chile) is a dominantly basaltic stratovolcano whose original ~ 3300 m altitude main cone experienced a catastrophic sector collapse at ~ 7.1 cal ka BP, producing a volcanic debris avalanche deposit (VDAD) with hummocky surface and ~ 6.4 km3 of volume. We carried out geological studies of its debris avalanche deposit, which was distributed to the W and displays a longitudinal facies transformation from edifice’s megablocks and block to mixed facies in distal areas (up to 25 km from the scar). Our observations support the behavior of the avalanche beginning as a translational slide, and then as plug flow when confined within the Laja River valley. Clay abundance and high content of hydrothermally altered material may suggest active participation of water; flow velocities are estimated to ~100 m s−1. We primarily identify the steep-sided flanks of the cone, and hydrothermal alteration promoted the edifice instability, while basement seismogenic structures may have ultimately triggered the landslide. Subsequent landslide-led events include the transformation of the volcanic activity with explosive eruptions producing a sequence of dilute pyroclastic density currents (PDCs) ending ~3.4 ky BP, and extensive lava effusion rapidly reconstructing the collapsed edifice. Moreover, the Antuco VDAD also blocked the natural output of the Laja Lake, increasing its level by ~200 m and then triggering cataclysmic outburst floods by dam rupture, preserved as high-energy alluvial beds with ages between 2.8 and 1.7 ky BP. The Antuco constitutes an excellent example of a critical chain of events initiated by a stratovolcano lateral collapse and warns for detailed hazard investigations to better comprehend its related impacts.

Poor neck posture and longer working duration during root canal treatment correlated with increased neck discomfort in dentists with

ObjectiveThis study investigated the effects of neck posture and working duration during each step of root canal treatment (i.e. opening the canal [OC], length determination, mechanical instrumentation, try main cone, and filling the root canal) on neck discomfort (ND) in dentists with <5‐years' endodontic experience.METHODSTwenty‐four dentists performed a one‐visit endodontic treatment of an upper molar in a phantom head model. A video was recorded to evaluate the dentists᾽ neck postures using the Modified‐Dental Operator Posture Assessment Instrument (M‐DOPAI) and treatment duration. The M‐DOPAI divides the dentists᾽ neck postures into three categories: acceptable, compromised, or harmful posture. The participants rated their ND using Borg᾽s CR‐10 scale every 10 min. and at the end of each treatment step. The relationships between neck posture/treatment duration and Borg᾽s CR‐10 scores were examined using partial correlation.RESULTSThe number of compromised and harmful neck postures during the endodontic procedure (r = 0.43, P = .04) and treatment duration (r = 0.58 P = .005) significantly correlated with ND at the end of treatment. The number of compromised and harmful neck postures during the OC step (r = 0.75, P < .001) and the duration of the OC step (r = .70, P < .001) significantly correlated with ND at the end of the step.CONCLUSIONPoor neck postures and long working duration during endodontic treatment correlated with ND among inexperienced dentists. Neck pain interventions should focus on neck postures and work duration during root canal treatment, particularly in the OC step.

A new middle Eocene bunodont artiodactyl from the Erlian Basin (Nei Mongol, China)

ABSTRACT A new genus and species of middle size bunodont artiodactyl (Mammalia), Erlianhyus primitivus, is established based on a partial maxilla with P3–M3 from the lower middle Eocene Irdin Manha Formation, Erlian Basin, Nei Mongol, China. Erlianhyus is characterised by a low tooth crown, bunodont cusps, a protocone smaller and lower than the paracone on P4, a large metaconule, reduced paraconule, no hypocone and styles on M1–3, and weak crista between the main cones on the upper cheek teeth. Erlianhyus is more similar in dental morphology to the Asian Myanmarius, Myaingtherium and Siamotherium rather than to other artiodactyls. Our cladistics analysis shows that Erlianhyus is positioned outside of the anthracotheriid-suoid-dichobunoid clade and is located more basally within the Artiodactyla, so now it is not referred to any known family or superfamily in artiodactyls.

Abundance and Structure of the Zooplankton Community During a Post-eruptive Process: The Case of the Submarine Volcano Tagoro (El Hierro; Canary Islands), 2013-2018

The mesozooplankton community was analyzed over a 6-year period (2013-2018) during the post-eruptive stage of the submarine volcano Tagoro, located south of the island of El Hierro (Canary Archipelago, Spain). Nine cruises from March 2013 to March 2018 were carried out in two different seasons, spring (March-April) and autumn (October). A high-resolution study was carried out across the main cones of Tagoro volcano, as well as a large number of reference stations surrounding El Hierro (unaffected by the volcano). The zooplankton community at the reference stations showed a high similarity with more than 85% of the variation in abundance and composition attributable to seasonal differences. Moreover, our data showed an increase in zooplankton abundance in waters affected by the volcano with a higher presence of non-calanoid copepods and a decline in the diversity of the copepod community, indicating that volcanic inputs have a significant effect on these organisms. Fourteen different zooplankton groups were found but copepods were dominant (79%) with 59 genera and 170 species identified. Despite the high species number, less than 30 presented a larger abundance than 1%. Oncaea and Clausocalanus were the most abundant genera followed by Oithona and Paracalanus (60%). Nine species dominated (&amp;gt;2%):O. media, O. plumifera, andO. setigeraamong the non-calanoids andM. clausi, P. nanus,P. parvus, C. furcatus, C. arcuicornis, andN. minoramong the calanoids. After the initial low abundance of the copepods as a consequence of the eruption, an increase was observed in the last years of the study, where besides the small Paracalanus and Clausocalanus, the Cyclopoids seem to have a good adaptive strategy to the new water conditions. The increase in zooplankton abundance and the decline in the copepod diversity in the area affected by the volcano indicate that important changes in the composition of the zooplankton community have occurred. The effect of the volcanic emissions on the different copepods was more evident in spring when the water was cooler and the mixing layer was deeper. Further and longer research is recommended to monitor the zooplankton community in the natural laboratory of the Tagoro submarine volcano.

Acoustic Emission Test of Changlongshan Pumped Storage Power Station Steel Bifurcation Pipe

The maximum test load of Changlongshan pumped storage power station steel bifurcation pipe is 10MPa. To ensure the safety of the water pressure test, acoustic emission is used to monitor the main welds of the crescent rib steel bifurcation and main cone. Taking NO.3 pipe’s data as an example, acoustic emission source location system was used to find the possible position of harmful defects, through the activity and intensity of the acoustic emission sources to confirm the defect significance. After analysis, the acoustic emission integrated level of the steel bifurcation pipe is in level II, the pipe’s data comply with the design requirements.

Chronology of the 2014–2016 Eruptive Phase of Volcán de Colima and Volume Estimation of Associated Lava Flows and Pyroclastic Flows Based on Optical Multi-Sensors

The eruption at Volcán de Colima (México) on 10–11 July 2015 represents the most violent eruption that has occurred at this volcano since the 1913 Plinian eruption. The extraordinary runout of the associated pyroclastic flows was never observed during the past dome collapse events in 1991 or 2004–2005. Based on Satellite Pour l’Observation de la Terre (SPOT) and Earth Observing-1 (EO-1) ALI (Advanced Land Imager), the chronology of the different eruptive phases from September 2014 to September 2016 is reconstructed here. A digital image segmentation procedure allowed for the mapping of the trajectory of the lava flows emplaced on the main cone as well as the pyroclastic flow deposits that inundated the Montegrande ravine on the southern flank of the volcano. Digital surface models (DSMs) obtained from SPOT/6 dual-stereoscopic and tri-stereopair images were used to estimate the volumes of some lava flows and the main pyroclastic flow deposits. We estimated that the total volume of the magma that erupted during the 2014–2016 event was approximately 40 × 107 m3, which is one order of magnitude lower than that of the 1913 Plinian eruption. These data are fundamental for improving hazard assessment because the July 2015 eruption represents a unique scenario that has never before been observed at Volcán de Colima. Volume estimation provides complementary data to better understand eruptive processes, and detailed maps of the distributions of lava flows and pyroclastic flows represent fundamental tools for calibrating numerical modeling for hazard assessment. The stereo capabilities of the SPOT6/7 satellites for the detection of topographic changes and the and the availability of EO-1 ALI imagery are useful tools for reconstructing multitemporal eruptive events, even in areas that are not accessible due to ongoing eruptive activity.

In vitro evaluation of gutta-percha dissolution ability of different solvents

Introduction: The removal of the filling material during the Endodontic retreatment is essential, so a better action of solvents on the gutta-percha is desired. Objective: To evaluate in vitro the gutta-percha dissolution ability of different solvents. Material and methods: Four solvents (xylol, eucalyptol, citrol, and orange oil) were applied on gutta-percha points, which had been later submitted to the weight loss analysis at 2, 5, and 10 minutes. For each solvent, 30 size #60 main cones were used, divided into three groups. Distilled water was used as control group. The statistical test applied was Kruskal-Wallis. Results: No statistically significant difference occurred among the solvents at 2 minutes (p &gt; 0.05); however, during this period, citrol had the best performance. In longer time intervals, the xylol showed differences compared to eucalyptol at 5 minutes and to eucalyptol and citrol at 10 minutes (p &lt; 0.05). The worst results were found for eucalyptol. Conclusion: This xylol was thesolvent with improved ability to dissolve the gutta-percha points, with better results at longer time periods.

The violent Strombolian eruption of 10 ka Pelado shield volcano, Sierra Chichinautzin, Central Mexico

Pelado volcano is a typical example of an andesitic Mexican shield with a summital scoria cone. It erupted ca. 10 ka in the central part of an elevated plateau in what is today the southern part of Mexico City. The volcano forms a roughly circular, 10-km wide lava shield with two summital cones, surrounded by up to 2.7-m thick tephra deposits preserved up to a distance of 3 km beyond the shield. New cartographic, stratigraphic, granulometric, and componentry data indicate that Pelado volcano was the product of a single, continuous eruption marked by three stages. In the early stage, a > 1.5-km long fissure opened and was active with mild explosive activity. Intermediate and late stages were mostly effusive and associated with the formation of a 250-m high lava shield. Nevertheless, during these stages, the emission of lava alternated and/or coexisted with highly explosive events that deposited a widespread tephra blanket. In the intermediate stage, multiple vents were active along the fissure, but activity was centered at the main cone during the late stage. The final activity was purely effusive. The volcano emitted > 0.9 km3 dense-rock equivalent (DRE) of tephra and up to 5.6 km3 DRE of lavas. Pelado shares various features with documented “violent Strombolian” eruptions, including a high fragmentation index, large dispersal area, occurrence of plate tephra, high eruptive column, and simultaneous explosive and effusive activity. Our results suggest that the associated hazards (mostly tephra fallout and emplacement of lava) would seriously affect areas located up to 25 km from the vent for fallout and 5 km from the vent for lava, an important issue for large cities built near or on potentially active zones, such as Mexico City.

Evaluation of the tip of standardized D0 gutta percha cones of four Rotary systems, by means of an endodontic ruler

ABSTRACT Objective : This study aimed to evaluate the D0 diameter of standardized gutta-percha cones for four mechanized systems: ProTaper Universal®, Mtwo®, Wave One® and Reciproc®. Methods: An endodontic calibrator ruler was used to measure the D0 diameter of 60 main cones of the above systems. Measurements were made according 3 scores as follows: gutta-percha cone fits exactly into the same hole as the endodontic ruler gauge (score 1), cone falls short of the ruler gauge whole size (score 2); or exceeding the ruler gauge hole size (score 3). The diameters D0 obtained were compared with the values reported by manufacturers. All data were analyzed by means of T Test, at 1% level of significance. Results: The average value measured was significantly higher than the measures established by manufacturers (p &lt;0.001). Conclusion : The gutta-percha cones of ProTaper Universal® systems Mtwo®, Wave One® and Reciproc® were not standardized, except for R40 cone of the Reciproc® system (Reciproc®). The trend was for variation in the D0 Diameter towards increasing measurement values.

In vitro evaluation of gutta-percha dissolution ability of different solvents

The removal of the filling material during the Endodontic retreatment is essential, so a better action of solvents on the gutta-percha is desired. Objective: To evaluate in vitro the gutta-percha dissolution ability of different solvents. Material and methods: Four solvents (xylol, eucalyptol, citrol, and orange oil) were applied on gutta-percha points, which had been later submitted to the weight loss analysis at 2, 5, and 10 minutes. For each solvent, 30 size #60 main cones were used, divided into three groups. Distilled water was used as control group. The statistical test applied was Kruskal-Wallis. Results: No statistically significant difference occurred among the solvents at 2 minutes (p &gt; 0.05); however, during this period, citrol had the best performance. In longer time intervals, the xylol showed differences compared to eucalyptol at 5 minutes and to eucalyptol and citrol at 10 minutes (p &lt; 0.05). The worst results were found for eucalyptol. Conclusion: This xylol was the solvent with improved ability to dissolve the gutta-percha points, with better results at longer time periods.

AH Plus extrusion into periapical tissue: literature review of main related properties and report of clinical cases

The sealers were developed for filling of root canals. Due to their physicochemical and technical properties used for obturation, often, extrusion is observed through apical constriction and occasionally by lateral and secondary canals. Objective: To review the literature on important properties to be considered in AH Plus sealer extrusion and report a case series of this sealer extrusion. Literature review: Articles evaluating the cytotoxicity and biocompatibility properties, besides flow and solubility were selected. Case report: In the presented cases, endodontic treatment was performed with rotary instrumentation and irrigation with 2.5% NaOCl. Obturation employed visual, tactile, and radiographic proof of gutta-percha main cone, and different obturation techniques. There were no reports of pain during and after endodontic treatment. Conclusion: AH Plus has adequate properties for a filling material and causes no major damage to the periapical tissues due to its little cytotoxic.

Emissions of Fe(II) and its kinetic of oxidation at Tagoro submarine volcano, El Hierro

Abstract The eruptive process that took place in October 2011 in the submarine volcano Tagoro off the Island of El Hierro and the subsequent degasification stage, five months later, have increased the concentration of TdFe(II) (Total dissolved iron(II)) in the waters nearest to the volcanic edifice. In order to detect any variation in concentrations of TdFe(II) due to hydrothermal emissions, three cruises were carried out two years after the eruptive process in October 2013, March 2014 and May 2015. The results from these cruises confirmed important positive anomalies in TdFe(II), which coincided with negatives anomalies in pHF,is (pH in free scale, at in situ conditions) located in the proximity of the main cone. Maximum values in TdFe(II) both at the surface, associated to chlorophyll a maximum, and at the sea bottom, were also observed, showing the important influence of organic complexation and particle re-suspension processes. Temporal variability studies were carried out over periods ranging from hours to days in the stations located over the main and two secondary cones in the volcanic edifice with positive anomalies in TdFe(II) concentrations and negative anomalies in pHF,is values. Observations showed an important variability in both pHF,is and TdFe(II) concentrations, which indicated the volcanic area was affected by a degasification process that remained in the volcano after the eruptive phase had ceased. Fe(II) oxidation kinetic studies were also undertaken in order to analyze the effects of the seawater properties in the proximities of the volcano on the oxidation rate constants and t1/2 (half-life time) of ferrous iron. The increased TdFe(II) concentrations and the low associated pHF,is values acted as an important fertilization event in the seawater around the Tagoro volcano at the Island of El Hierro providing optimal conditions for the regeneration of the area.

Impact of the ‘Little Ice Age’ climate cooling on the maar lake ecosystem affected by penguins: A lacustrine sediment record, Penguin Island, West Antarctica

A Pliocene-age volcano on Penguin Island became active again in the Pleistocene/Holocene, forming the main cone of the island – Deacon Peak, and leaving late-Holocene phreatomagmatic craters, including ‘Petrel Crater’, about 200 m in diameter and filled currently by a maar lake with a flat bottom at 18 m water depth. Petrographic, geochemical, photosynthetic pigment, and diatom data from the 72-cm-long sediment core reveal that the crater was initially a marine lagoon with typical phytoplankton assemblages. Most probably, tectonic–volcanic activity about 1250 years ago, documented in tephra fallout, triggered an abrupt glacio-isostatic uplift that separated the lake from the sea. The horizon of tephra, probably from the Deception Island volcano, marks a sudden change in environment from brackish to lacustrine. The ecological evolution of the lake was initially constrained by an uplift, whereas the influence of marine water vanished with time, the lake became meromictic, and the freshwater mixolimnion layer expanded, while the monimolimnion became anoxic due to the influence of a penguin rookery situated on the shore. During the ‘Little Ice Age’ (LIA), the maar may have been covered by permanent ice. A discharge of mineralized guano from the possibly enlarged penguin rookery on the lake shore caused an expansion of the anoxic monimolimnion to the ice surface and an important reduction of autochthonous lacustrine biota of the maar, whereas a substantially increased participation of allochthonous biota passively supplied with guano. That record in the lake sediment core reaffirms the occurrence of a regional LIA event in the maritime Antarctic.

AH Plus extrusion into periapical tissue: literature review of main related properties and report of clinical cases

The sealers were developed for filling of root canals. Due to their physicochemical and technical properties used for obturation, often, extrusion is observed through apical constriction and occasionally by lateral and secondary canals. Objective: To review the literature on important properties to be considered in AH Plus sealer extrusion and report a case series of this sealer extrusion. Literature review: Articles evaluating the cytotoxicity and biocompatibility properties, besides flow and solubility were selected. Case report: In the presented cases, endodontic treatment was performed with rotary instrumentation and irrigation with 2.5% NaOCl. Obturation employed visual, tactile, and radiographic proof of gutta-percha main cone, and different obturation techniques. There were no reports of pain during and after endodontic treatment. Conclusion: AH Plus has adequate properties for a filling material and causes no major damage to the periapical tissues due to its little cytotoxic.