Correlation between Microleakage and Tubules Penetration of an Endodontic Sealer

Objective: The aim of the study was to verify the existence of a correlation between fluid filtration and tubular penetration of an endodontic sealer. Methods: Ten pairs of maxillary incisors with a single root canal, circular cross-section, similar sizes and dimensions were selected from a collection. Teeth from each pair were randomly divided in 2 groups. All canals were instrumented using NiTi WaveOne Primary instrument (#25) (Dentsply, Maillefer). In the group 1 all canals were irrigated with 1 mL of 5,25% NaOCl for 30s (Ogna, Muggi\uf2, Italy), followed by 0.5 mL of 10% EDTA for 30 s (Ogna). In the group 2 it\u2019s used the same protocol but without the EDTA. A final irrigation of 2.0 mL 5,25% NaOCl for 3m was performed. Root filling was performed with Thermafil-obturators (Dentsply Tulsa, Tulsa, OK) with TopSeal (Dentsply, Maillefer) mixed with 0.1 wt% alizarin to evaluate the penetration depth of the sealer into tubules with confocal microscope (Leica, Wetzlar, Germany). Microleakage i.e. the volume of a calcein solution infiltrated into the root canal and tubules were evaluated using a digital fluid flow-meter and a confocal microscope. Results: Confocal microscopy showed a penetration of the sealer into tubules in group 1 of approx. 370 \u3bcm at 3 mm from the apex and 630 \u3bcm at 5 mm while in group 2 of approx. 22 \u3bcm at 3 mm and 37 \u3bcm at 5 mm from the apex. The volume of the infiltrated fluid was 0.353 x 10-4 mm3 for group 1 and 0.397 x 10-4 mm3 for group 2. The data of calcein penetration into the root canal were in agreement with the fluid filtration results. Conclusion: A correlation seems to be present between sealer penetration into dentinal tubules and sealability of Thermafil-obturators and TopSeal in root canal shaped with WaveOne Primary file

Arginine-Based Toothpaste Induces Calcium-Phosphates Deposits on Dentin Surface and Tubules

Objective: To test the ability of a calcium carbonate-containing toothpaste for dentinal hypersensitivity to occlude the exposed open tubules of dentin surface. Method: Dentine slices (0.9±0.1 thick) and crown segments (1.5±0.3 cm thick) from human third molars were used. Elmex Sensitive Professional toothpaste (GABA Int AG, Therwill, Switzerland) containing as main active ingredients arginine (8%), sodium monofluorophosphate (1450 ppm Fˉ) and calcium carbonate, was applied (3 min) on coronal dentin surface. Fluid flow/permeation through the dentin thickness (i.e. permeability or hydraulic conductance, Lp in microliters/min) was evaluated using a digital fluid flow-meter after smear layer formation, after EDTA treatment, after Elmex toothpaste treatment (t=0) and after soaking for 1, 7, 28 days in simulated body fluid (HBSS). Tubules occlusion, elemental analysis and mineral content were studied by ESEM-EDX. Toothpaste penetration inside dentinal tubules was analyzed by laser confocal microscopy using calcein as tracer. Result: Lp of EDTA-treated dentin significantly decreased after treatment with Elmex toothpaste (-73,32% at t=0) and after soaking in HBSS the Lp values further decreased (-77,69% at 24h, -78,18% at 7d, -83,01% at 28d). After 24h and 7d in HBSS, ESEM on Elmex-treated dentin showed the presence of precipitates on dentin surface and in the dentinal tubules; EDX revealed N (from arginine) and F (from monofluorophosphate) of the toothpaste. Lp remained significantly lower (-78,18%) than EDTA- treated control dentin. After 28d in HBSS, a calcium phosphate layer was detected on dentin surface so tubules were not visible. EDX detected F and no N. No CaP deposits were found on EDTA-treated dentin soaked in HBSS. Confocal microscopy showed an average penetration depth of the toothpaste into the dentinal tubules of ~85 microns. Conclusion: Elmex sensitive toothpaste can reduce the fluid movement into the exposed dentinal tubules and favour the formation of calcium phosphate minerals

Bioactivity, physical and chemical properties of MTA mixed with propylene glycol

AbstractObjective To investigate the physical (setting time, hardness, flowability, microstructure) and chemical (pH change, calcium release, crystallinity) properties and the biological outcomes (cell survival and differentiation) of mineral trioxide aggregate (MTA) mixed using different proportions of propylene glycol (PG) and water.Material and Methods White MTA was mixed with different water/PG ratios (100/0, 80/20 and 50/50). Composition (XRD), microstructure (SEM), setting time (ASTM C266-13), flowability (ANSI/ADA 57-2000), Knoop hardness (100 g/10 s) and chemical characteristics (pH change and Ca2+ release for 7 days) were evaluated. Cell proliferation, osteo/odontoblastic gene expression and mineralization induced by MTA mixed with PG were evaluated. MTA discs (5 mm in diameter, 2 mm thick) were prepared and soaked in culture medium for 7 days. Next, the discs were removed and the medium used to culture dental pulp stem cells (DPSC) for 28 days. Cells survival was evaluated using MTS assay (24, 72 and 120 h) and differentiation with RT-PCR (ALP, OCN, Runx2, DSPP and MEPE) and alizarin red staining (7 and 14 days). Data were analysed using one-way ANOVA and Tukey’s post-hoc analysis (a=0.05).Results The addition of PG significantly increased setting time, flowability and Ca2+ release, but it compromised the hardness of the material. SEM showed that 50/50 group resulted porous material after setting due to the incomplete setting reaction, as shown by XRD analysis. The addition of PG (80/20 and 50/50) was not capable to improve cell proliferation or to enhance gene expression, and mineralized deposition of DPSC after 7 and 14 days as compared to the 100/0.Conclusion Except for flowability, the addition of PG did not promote further improvements on the chemical and physical properties evaluated, and it was not capable of enhancing the bioactivity of the MTA

Measurement of CP-violation asymmetries in D0 to Ks pi+ pi-

We report a measurement of time-integrated CP-violation asymmetries in the resonant substructure of the three-body decay D0 to Ks pi+ pi- using CDF II data corresponding to 6.0 invfb of integrated luminosity from Tevatron ppbar collisions at sqrt(s) = 1.96 TeV. The charm mesons used in this analysis come from D*+(2010) to D0 pi+ and D*-(2010) to D0bar pi-, where the production flavor of the charm meson is determined by the charge of the accompanying pion. We apply a Dalitz-amplitude analysis for the description of the dynamic decay structure and use two complementary approaches, namely a full Dalitz-plot fit employing the isobar model for the contributing resonances and a model-independent bin-by-bin comparison of the D0 and D0bar Dalitz plots. We find no CP-violation effects and measure an asymmetry of ACP = (-0.05 +- 0.57 (stat) +- 0.54 (syst))% for the overall integrated CP-violation asymmetry, consistent with the standard model prediction.Comment: 15 page

Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

X-ray emission from the Sombrero galaxy: discrete sources

We present a study of discrete X-ray sources in and around the bulge-dominated, massive Sa galaxy, Sombrero (M104), based on new and archival Chandra observations with a total exposure of ~200 ks. With a detection limit of L_X = 1E37 erg/s and a field of view covering a galactocentric radius of ~30 kpc (11.5 arcminute), 383 sources are detected. Cross-correlation with Spitler et al.'s catalogue of Sombrero globular clusters (GCs) identified from HST/ACS observations reveals 41 X-rays sources in GCs, presumably low-mass X-ray binaries (LMXBs). We quantify the differential luminosity functions (LFs) for both the detected GC and field LMXBs, whose power-low indices (~1.1 for the GC-LF and ~1.6 for field-LF) are consistent with previous studies for elliptical galaxies. With precise sky positions of the GCs without a detected X-ray source, we further quantify, through a fluctuation analysis, the GC LF at fainter luminosities down to 1E35 erg/s. The derived index rules out a faint-end slope flatter than 1.1 at a 2 sigma significance, contrary to recent findings in several elliptical galaxies and the bulge of M31. On the other hand, the 2-6 keV unresolved emission places a tight constraint on the field LF, implying a flattened index of ~1.0 below 1E37 erg/s. We also detect 101 sources in the halo of Sombrero. The presence of these sources cannot be interpreted as galactic LMXBs whose spatial distribution empirically follows the starlight. Their number is also higher than the expected number of cosmic AGNs (52+/-11 [1 sigma]) whose surface density is constrained by deep X-ray surveys. We suggest that either the cosmic X-ray background is unusually high in the direction of Sombrero, or a distinct population of X-ray sources is present in the halo of Sombrero.Comment: 11 figures, 5 tables, ApJ in pres

Azimuthal anisotropy of charged particles at high transverse momenta in PbPb collisions at sqrt(s[NN]) = 2.76 TeV

The azimuthal anisotropy of charged particles in PbPb collisions at nucleon-nucleon center-of-mass energy of 2.76 TeV is measured with the CMS detector at the LHC over an extended transverse momentum (pt) range up to approximately 60 GeV. The data cover both the low-pt region associated with hydrodynamic flow phenomena and the high-pt region where the anisotropies may reflect the path-length dependence of parton energy loss in the created medium. The anisotropy parameter (v2) of the particles is extracted by correlating charged tracks with respect to the event-plane reconstructed by using the energy deposited in forward-angle calorimeters. For the six bins of collision centrality studied, spanning the range of 0-60% most-central events, the observed v2 values are found to first increase with pt, reaching a maximum around pt = 3 GeV, and then to gradually decrease to almost zero, with the decline persisting up to at least pt = 40 GeV over the full centrality range measured.Comment: Replaced with published version. Added journal reference and DO

Compressed representation of a partially defined integer function over multiple arguments

In OLAP (OnLine Analitical Processing) data are analysed in an n-dimensional cube. The cube may be represented as a partially defined function over n arguments. Considering that often the function is not defined everywhere, we ask: is there a known way of representing the function or the points in which it is defined, in a more compact manner than the trivial one

Search for new physics with same-sign isolated dilepton events with jets and missing transverse energy

A search for new physics is performed in events with two same-sign isolated leptons, hadronic jets, and missing transverse energy in the final state. The analysis is based on a data sample corresponding to an integrated luminosity of 4.98 inverse femtobarns produced in pp collisions at a center-of-mass energy of 7 TeV collected by the CMS experiment at the LHC. This constitutes a factor of 140 increase in integrated luminosity over previously published results. The observed yields agree with the standard model predictions and thus no evidence for new physics is found. The observations are used to set upper limits on possible new physics contributions and to constrain supersymmetric models. To facilitate the interpretation of the data in a broader range of new physics scenarios, information on the event selection, detector response, and efficiencies is provided.Comment: Published in Physical Review Letter