Vertical Loss Research Articles

Bone and soft tissue changes after alveolar ridge preservation using PRF socket plug technique versus socket plug technique:

Aim: The aim of this study was to compare platelet rich fibrin “PRF socket plug technique”versus the traditionally used “socket plug technique” to improve bone quality without affecting itsvolumetric stability. Research question: In mandibular premolars socket preservation, will “PRFsocket plug” technique improve bone quality without affecting bone quantity, when compared to‘socket plug” technique? Materials and Methods: This was a split-mouth randomized controlledtrial conducted on 9 patients. For each patient, bilateral socket preservation was performed. PRFsocket plug technique (intervention) was performed for one side, while the other was performedusing the traditional socket plug technique (control). After 6 months, bone and soft tissue changeswere measured. Horizontal and vertical alveolar ridge loss and loss percentage were measuredusing cone-beam CT. Bone quality was measured by histomorphometric analysis of areapercentages of mineralized trabecular bone of core biopsies. Keratinized mucosa changes weremeasured using Williams graduated periodontal probe. Results: Intervention group showed slightlyhigher horizontal bone loss, loss percentage, vertical bone loss, loss percentage (1.36 mm, 16.98 %,1.07mm, 7.99 %) with no statistically significant difference when compared to the control group(1.14mm, 13.89 %, 0.97 mm, 7.21 %). Histomorphometric analysis showed higher new boneformation (34.11 %) in intervention group compared to the control group (30.78%) with no statisticallysignificant difference. Both groups showed keratinized mucosa gain (1.28 mm intervention,1 mm control) with no statistically significant difference. Conclusions: Socket plug techniqueis an effective technique for alveolar ridge preservation; PRF clot represents an easy, successful,and economical method to cover the graft in socket plug technique; PRF socket plug techniquerepresents a promising alternative to the routinely used socket plug technique.

Ambient Noise Vertical Directionality and Reflection Loss Estimates for a Shallow Tropical Site with a Fast Sound Speed Bottom

For high frequency ocean acoustic modeling applications, seabed reflection loss is a useful alternative input compared to conventional geoacoustic model parameters. Reflection loss can be estimated by comparing the noise intensity of the up and down components of the ambient noise vertical directionality pattern. The potential of this method is demonstrated with experimental data spanning one week, collected off shallow east coast of India using a 21 element vertical hydrophone array. The compact and easily operable vertical array has been designed for high frequency directionality estimation in the band 2–10 kHz. The ambient noise data are beam formed to arrive at the vertical directionality pattern. Further reflection loss values as a function of frequency and grazing angle have been estimated for 1/3 octave bands for a sandy sea bed in warm tropical waters. This has been compared with modeled reflection loss estimates using OASR reflection loss module of OASES. This will serve as inputs to propagation models for applications such as inverse techniques, ambient noise modelling, and sonar system performance prediction.

Chemical Head Loss Measurements on Multi-Constituent Debris Beds in Small-Scale Experiments

A series of experiments on vertical head loss modules or columns to measure conventional and chemical head loss was carried out to support the resolution of Generic Safety Issue 191 for the Vogtle nuclear power plant (NPP). The head loss (conventional and chemical) was measured on multi-constituent fibrous debris beds of different particulate-to-fiber ratios (η). The debris beds were generated on a horizontal screen following the new procedure developed at the University of New Mexico and are summarized herein. The generated debris beds have been shown to produce repeatable and stable conventional head loss (CHL) and have the ability to detect chemical surrogates. Prototypical Vogtle NPP containment debris materials were used to form three different particulate-to-fiber–ratio (η) debris beds: 6.89 (thin bed), 2 (intermediate bed), and 1.15 (thick bed). The particulates were presented as 90% epoxy paint, 5% inorganic zinc, and 5% latent debris dirt by mass. The obtained results show that the measured CHL increased as the particulate mass increased in the debris beds. The average measured CHL values were 9.37, 6.4, and 5.66 H2O'' for η = 1.15, 2, and 6.89 debris beds, respectively. The debris beds with η = 2 and 1.15 were selected for the chemical head loss experiments.Standard aluminum (Al) chemical precipitates with specific batches were introduced to the head loss columns, and chemical head loss was measured. Precipitates prepared following the WCAP-16530-NP-A procedure [Lane et al., WCAP-16530-NP-A, “Evaluation of Post-Accident Chemical Effects in Containment Sump Fluids to Support GSI-191,” Westinghouse Electric Company (2008)] or formed in situ by injecting metal salts under two different rates (0.75 and 7.5 mL/min) were tested. The results show that the thin debris bed (~10 mm) was more sensitive to the chemical precipitates prepared following the WCAP procedure compared to the intermediate debris bed (~25 mm) and thick debris bed (~55 mm). The measured chemical head loss was 0.35, 0.1, and 0.02 H2O''/mg of Al filtered by the debris beds. The in situ injection method has shown higher measured chemical head loss per unit mass of filtered precipitates than the WCAP surrogates for the debris beds of η = 2 (intermediate bed) and 1.15 (thick bed). Also, the results show a nonconclusive effect on the injection rate of metal salt to form in situ chemical precipitates on the measured chemical head loss.

Unilateral complex partial denture performance evaluation: 5 years follow up clinical study

Summary Introduction Removable partial denture (RPD) is common treatment option for unilateral partially edentulous patients not indicated for implant therapy. Unilateral complex partial denture (UCPD) could be an alternative approach to RPD treatment, but there is lack of evidence about UCPD treatment outcomes during the long-term clinical performance. The aim of this this study was to use periodontal, prosthodontic and participant satisfaction measures to evaluate the long-term clinical performance of UCPD. Material and methods This 5 year follow-up clinical study evaluated pocket probing depth (PPD) and vertical clinical attachment loss (CAL-V) of direct abutment (DA), indirect abutment (IA) and control teeth (CT). Also complications and failures of UCPD were analysed using questionnaire of participant satisfaction with UCPD (stability, comfort and manipulation). Results Evaluation of data showed that CAL-V and PPD significantly increased over time for DA, IA and CT (p<0.0001), but the tooth function (DA, IA and CT) did not significantly influence changes in PPD and CAL-V. The fracture of one abutment tooth and increase of the number of artificial teeth deformations (p=0.039) were observed after 5 years. Participant satisfaction with denture after 1 year and 5 years vs. 7 days was significantly improved. Conclusion Despite limitations of this clinical study and assuming regular oral maintenance with proper indication, UCPD might be considered as good treatment option for Kennedy II rehabilitation in patients not indicated for implant therapy or who cannot tolerate extensive RPD design.

Influence of low-temperature degradation on the wear characteristics of zirconia against polymer-infiltrated ceramic-network material

Statement of problemLow-temperature degradation may affect zirconia restorations during their clinical service. Concerns have been raised about the effect of low-temperature degradation on the wear behavior of zirconia. Moreover, the wear resistance of this novel polymer-infiltrated ceramic-network material needs to be better evaluated. PurposeThe purpose of this in vitro study was to investigate the influence of aging on the wear resistance of zirconia opposing polymer-infiltrated ceramic-network material. Material and methodsTwelve specimens for 2 newly developed polymer-based materials (a polymer-infiltrated ceramic-network material VITA ENAMIC and a resin nanocomposite material Lava Ultimate), 2 commonly used glass-ceramic materials (IPS e.max CAD and VITABLOCS Mark II), and 2 conventional composite resin materials (VITA CAD-Temp and PMMA Disk) were tested; human enamel was used as a control group. The wear simulator used was a ball-on-disk type with zirconia balls, with and without autoclaving (134°C, 200 kPa, 20 hours) as antagonists. The vertical loss and volume loss of specimens and the roughness average of zirconia antagonists were measured with a 3-dimensional optical profilometer. Vickers hardness values were determined using a micro-Vickers hardness tester. Data were statistically analyzed with a mixed-model ANOVA for wear loss (vertical loss [μm] and volume loss [mm3]) and roughness average (μm) of zirconia antagonists and with the Kruskal-Wallis test for Vickers hardness values (α=.05). The Spearman correlation coefficient was used to determine the relationship between wear loss and hardness. ResultsResults showed that specimens opposing the non-aged zirconia balls demonstrated significantly higher wear than those opposing the aged ones (P<.001). The polymer-infiltrated ceramic-network material VITA ENAMIC group (vertical loss=27.44-33.53 μm, volume loss=0.0198-0.315 mm3) and the resin nanocomposite material Lava Ultimate group (vertical loss=24.42-27.83 μm, volume loss=0.0159-0.0233 mm3) showed lower vertical loss and volume loss than the conventional composite resin groups (vertical loss=43.95-61.87 μm, volume loss=0.0395-0.0593 mm3) but higher wear than the glass-ceramic groups (IPS e.max CAD and VITABLOCS Mark II; vertical loss=8.95-11.47 μm, volume loss=0.0072-0.0094 mm3) and human enamel (vertical loss=9.95-12.32 μm; volume loss=0.0089-0.0103 mm3). The aged zirconia antagonists indicated greater roughness average values than the aged zirconia balls after the wear test (P<.001). Distinct abrasion-induced tracks were observed on the contact surfaces of the aged zirconia antagonists. ConclusionsEven though zirconia ceramic subjected to low-temperature degradation exhibited increased roughness after the wear test, it was still nonabrasive toward opposing materials. The polymer-infiltrated ceramic-network material showed intermediate wear resistance compared with glass-ceramic and conventional composite resin.

3-Dimensional Volumetric Analysis of Double Socket-shield for Maximum Tissue Preservation at Immediate Implant Replacement of Multi-Rooted Teeth, A Case Report

Extraction Socket Healing undergoes a remodeling process that leads to vertical and horizontal tissue loss. Ridge volume alteration embeds a huge challenge on restoratively oriented three-dimensional placement of dental Implants. Socket shield technique demonstrated a histologic and clinical evidence on preventing soft and hard tissue alteration following tooth extraction. This case report describes an immediate implant placement with modification on socket-shied technique, where a buccal and palatal tooth fragments where prepared on buccal and palatal roots respectively of a failing upper first premolar, with two divergent roots. 3D deviation analysis of alveolar bone showed minimal loss of volume (-0.052mm, Avg+/-: 0.128/-0.232, SD 0.48), as well as, 3D deviation analysis of the ridge showed minimal loss of volume (-0.122mm, Avg+/-: 0.029/-0.202, SD 0.263). This Double Socket-shield procedure showed to be a feasible treatment option for maximum tissue preservation at immediate implant replacement of multi-rooted teeth.

Forest Above-Ground Biomass Estimation Using Single-Baseline Polarization Coherence Tomography with P-Band PolInSAR Data

Forest above ground biomass (AGB) extraction using Synthetic Aperture Radar (SAR) images has been widely used in global carbon cycle research. Classical AGB inversion methods using SAR images are mainly based on backscattering coefficients. The polarization coherence tomography (PCT) technology which can generate vertical profiles of forest relative reflectivity, has the potential to improve the accuracy of biomass inversion. The relationship between vertical profiles and forest AGB is modeled by some parameters defined based on geometric characteristics of the relative reflectivity distribution curve. But these parameters are defined without physical characteristics. Among these parameters, tomographic height (TomoH) is considered as the most important one. However, TomoH only corresponds to the highest volume relative reflectivity, which is lower than the actual forest height, affecting the accuracy of forest height and AGB inversion. In this paper, we introduce a new parameter, the canopy height (Hac), for AGB inversion by analyzing the vertical backscatter power loss. Then, we construct an inversion model based on the combination of the new parameter (Hac) and other parameters from the tomographic profile. The P-band polarimetric SAR datasets of the European Space Agency (ESA) BioSAR 2008 campaign acquired over Krycklan Catchment are selected for the verification experiment at two different flight directions. The results show that Hac performs better in estimating forest height and AGB than TomoH does. The inversion root mean square error (RMSE) of the proposed method is 18.325 t ha−1, and the result of using TomoH is 21.126 t ha−1.

Quantification of vertical and horizontal loss of Hg in Jiaozhou Bay 1988

This paper quantified the horizontal and vertical loss of Hg in Jiaozhou Bay based on investigation data on surface and bottom waters in six sampling sites in April and July 1988. Results showed that the horizontal absolute loss amounts of Hg contents in surface and bottom waters were 0.004-0.048 μg L-1, and the horizontal relative loss amounts of Pb contents were 8.16-64.00%, respectively. The vertical absolute dilution amounts of Pb contents were 0.000-0.008 μg L-1, and the vertical relative dilution amounts were 0.00-16.32%. The vertical absolute accumulation amounts of Pb contents were 0.003-0.042 μg L-1, and the vertical relative accumulation amounts were 6.25-56.00%. During the transporting process through the bay mouth, no matter from the internal waters to the open water, or from the open waters to the internal waters, the loss of Hg at horizontal direction could be 8.16-64.00%. In case of the horizontal loss of Hg in surface waters was relative high/low, the horizontal loss of Hg in bottom waters would be also relative high/low. The changes of Hg contents in surface and bottom waters were determined by the migration distance of Hg in surface waters.

Distribution of siderophore gene systems on a Vibrionaceae phylogeny: Database searches, phylogenetic analyses and evolutionary perspectives.

Siderophores are small molecules synthesized and secreted by bacteria and fungi to scavenge iron. Extracellular ferri-siderohores are recognized by cognate receptors on the cell surface for transport over membranes. Several siderophore systems from Vibrionaceae representatives are known and well understood, e.g., the molecular structure of the siderophore, the biosynthesis gene cluster and pathway, and the gene expression pattern. Less is known about how these systems are distributed among the ~140 Vibrionaceae species, and which evolutionary processes contributed to the present-day distribution. In this work, we compiled existing knowledge on siderophore biosynthesis systems and siderophore receptors from Vibrionaceae and used phylogenetic analyses to investigate their organization, distribution, origin and evolution. Through literature searches, we identified nine different siderophore biosynthesis systems and thirteen siderophore receptors in Vibrionaceae. Homologs were identified by BLAST searches, and the results were mapped onto a Vibrionaceae phylogeny. We identified 81 biosynthetic systems distributed in 45 Vibrionaceae species and 16 unclassified Vibrionaceae strains, and 409 receptors in 89 Vibrionaceae species and 49 unclassified Vibrionaceae strains. The majority of taxa are associated with at least one type of siderophore biosynthesis system, some (e.g., aerobactin and vibrioferrin) of which are widely distributed in the family, whereas others (i.e., bisucaberin and vibriobactin) are found in one lineage. Cognate receptors are found more widespread. Phylogenetic analysis of three siderophore systems (piscibactin, vibrioferrin and aerobactin) show that their present-day distribution can be explained by an old insertion into Vibrionaceae, followed mainly by stable vertical evolution and extensive loss, and some cases of horizontal gene transfers. The present work provides an up to date overview of the distribution of siderophore-based iron acquisition systems in Vibrionaceae, and presents phylogenetic analysis of these systems. Our results suggest that the present-day distribution is a result of several evolutionary processes, such as old and new gene acquisitions, gene loss, and both vertical and horizontal gene transfers.

Quantile estimators with orthogonal pinball loss function

AbstractTo guarantee stable quantile estimations even for noisy data, a novel loss function and novel quantile estimators are developed, by introducing the effective concept of orthogonal loss considering the noise in both response and explanatory variables. In particular, the pinball loss used in classical quantile estimators is improved into novel orthogonal pinball loss (OPL) by replacing vertical loss by orthogonal loss. Accordingly, linear quantile regression (QR) and support vector machine quantile regression (SVMQR) can be respectively extended into novel OPL‐based QR and OPL‐based SVMQR models. The empirical study on 10 publicly available datasets statistically verifies the superiority of the two OPL‐based models over their respective original forms in terms of prediction accuracy and quantile property, especially for extreme quantiles. Furthermore, the novel OPL‐based SVMQR model with both OPL and artificial intelligence (AI) outperforms all benchmark models, which can be used as a promising quantile estimator, especially for noisy data.

Wear of polyetherketoneketones — Influence of titanium dioxide content and antagonistic material

ObjectiveThe aim of this laboratory study was to analyze the influence of titanium dioxide (TiO2) content and antagonistic material on the wear of polyetherketoneketones (PEKKs). MethodsTwenty-four disk-shaped specimens of two PEKK materials containing either 10wt% or 20wt% TiO2 particles (P10 and P20) were dynamically loaded in a chewing simulator with 49N and additional thermal cycling (5–55°C). Subgroups of 8 specimens each were loaded with spherical antagonists made from either steatite ceramic (St), zirconia (Zr), or the same PEKK material (P10 or P20). After 120,000, 240,000, 480,000, 840,000, and 1,200,000 loading cycles the vertical substance loss and the volume loss of the loaded specimens were evaluated using a laser scanner. Data were checked considering the normal distribution (Shapiro–Wilk test) and were inspected for significant differences by means of single factor variance analyses and post hoc pair comparison (Games-Howell test). ResultsAfter 1,200,000 chewing cycles, statistical analyses revealed a significant influence of the antagonistic material. A significant difference was also found between the tested PEKKs if Zr was used as the antagonist. The volume loss ranged from between 0.073mm3 (P20-P20) and 0.228mm3 (P10-St), and the vertical substance loss ranged between 73.71μm (P20-P20) and 115.268μm (P10-Zr). SignificanceThe inclusion of TiO2 particles influences the wear behavior of PEKK materials.

Performance Evaluation of LOS and NLOS Vertical Inhomogeneous Links in Underwater Visible Light Communications

In this paper, underwater visible light communication (UWVLC) vertical links are modeled and evaluated, taking account of the inhomogeneous nature of underwater (UW) environment. An equivalent simplified model of stratified $N$ layers is employed in which variations in refractive index and attenuation profiles across UW depth are considered. A generalized path loss expression is deduced which allows estimation of the vertical link loss prior to link design. Mathematical expressions of the received power for line-of-sight (LOS) and non-line-of-sight (NLOS) links between transmitters (Tx) and receivers are deduced. We evaluate the performance by computing the received power and bit error rate for inhomogeneous underwater links. Numerical examples are used to illustrate the proposed models. Deviations from expected results when considering a homogeneous underwater model are discussed. A simple underwater bilayer model is then introduced, which is considered a rough approximate model in comparison to the stratified $N$ layers model. This model assists in estimating the UW link behavior without extensive calculations. The conditions necessary for applying this model are discussed and justified. Moreover, the effects of Tx orientation along with narrowing the transmitted light cone on LOS and NLOS vertical links are examined. A Tx power saving of 30%–50% in UWVLC links is proved to be achieved by rotating the Tx and narrowing its emitted light cone.

Sinteza PMMA/ZnO nanodelcev kompozitov za izdelavo zob iz umetnih smol

Wear resistance is one of the most important physical properties of the artificial teeth used in acrylic dentures. The goal of this research was to synthesize a new composite material made of matrix Poly-(methyl methacrylate)-PMMA with different percentages (2 % and 3 % of volume fractions) of zinc-oxide nanoparticles (ZnO NPs) as reinforcing elements, to improve its mechanical properties. The dynamic mechanical behaviour of this composite was studied through the DMA method in comparison to the pure PMMA supported by the characterization of their microstructures. Then the wear resistance was analysed on the samples, which were prepared in the form of teeth. In this context their vertical height loss was measured after 100,000 chewing cycles on a chewing simulator, before and after the artificial thermal ageing. Investigations showed that the PMMA/ZnO NP composites dampened the vibrations better than the pure PMMA, which could be assigned to the homogenous distribution of ZnO NPs in the PMMA matrix. It was found that the mean vertical height loss for the pure PMMA teeth was significantly higher (more than 4 times) compared to composite teeth made with ZnO NPs. Introducing the thermal artificial ageing led to the finding that there was no effect on the height loss by the composite material with 3 % of volume fractions of ZnO NPs. Based on this it was concluded that PMMA/ZnO NPs composites showed improved in-vitro wear resistance compared to acrylic-resin denture teeth, so this new composite material should be preferred when occlusal stability is considered to be of high priority.

The Facial Platysma and Its Underappreciated Role in Lower Face Dynamics and Contour.

The platysma is a superficial muscle involved in important features of the aging neck. Vertical bands, horizontal lines, and loss of lower face contour are effectively treated with botulinum toxin A (BoNT-A). However, its pars facialis, mandibularis, and modiolaris have been underappreciated. To demonstrate the role of BoNT-A treatment of the upper platysma and its impact on lower face dynamics and contour. Retrospective analysis of cases treated by an injection pattern encompassing the facial platysma components, aiming to block the lower face as a whole complex. It consisted of 2 intramuscular injections into the mentalis muscle and 2 horizontal lines of BoNT-A injections superficially performed above and below the mandible (total dose, 16 onabotulinumtoxinA U/side). Photographs were taken at rest and during motion (frontal and oblique views), before and after treatment. A total of 161 patients have been treated in the last 2 years with the following results: frontal and lateral enhancement of lower facial contour, relaxation of high horizontal lines located just below the lateral mandibular border, and lower deep vertical smile lines present lateral to the oral commissures and melomental folds. The upper platysma muscle plays a relevant role in the functional anatomy of the lower face that can be modulated safely with neuromodulators.

Three years of morphologic changes at a bowl blowout, Cape Cod, USA

This study presents measurements of blowout topography obtained with annual terrestrial laser surveys carried out over a three-year period at a single, large bowl blowout located in the Provincelands Dunes section of Cape Cod National Seashore, in Massachusetts. The study blowout was selected because its axis is aligned with northwest winds that dominate the region, and because it was seemingly interacting with a smaller saucer blowout that had recently formed on the southern rim of the primary feature. Assuming that blowouts enlarge both horizontally and vertically in response to the wind regime, the objectives of the study were to determine both the amount of horizontal growth that the blowout experiences annually and the spatial patterns of vertical change that occur within the blowout. Changes to the blowout lobe surrounding the feature were also determined for areas with sparse enough vegetation cover to allow laser returns from the sand surface. The results show that the blowout consistently expanded outward during the three years, with the greatest expansion occurring at its southeast corner, opposite the prevailing winds. The most significant occurrence was the removal, in the first year, of the ridge that separated the two blowouts, resulting in a major horizontal shift of the southern rim of the new combined blowout. This displacement then continued at a lesser rate in subsequent years. The rim also shifted horizontally along the northwest to northeast sections of the blowout. Significant vertical loss occurred along the main axis of the blowout with the greatest loss concentrated along the southeast rim. On the lobe, there were large areas of deposition immediately downwind of the high erosion zones inside the blowout. However, there were also small erosion areas on the lobe, extending downwind from eroding sections of the rim. This study shows that: 1. blowouts can experience significant areal and volumetric changes in short periods of time; 2. significant changes may occur relatively suddenly when adjacent blowouts combine into a single feature; and 3. the sediment transport paths are highly controlled by the topography. The joining of two blowouts not only creates a new larger feature, but it also releases large amounts of sediment that are then distributed across the landscape downwind, creating a potential for major changes to a landscape over the longer term.

SPACE CLOSURE IN BIALVEOLAR DENTAL PROTRUSION CASES - A COMPARATIVE COMBINATION METHOD

Objective: To measure and compare the amount, rate and anchor loss after the en masse retraction of all anteriors with titanium mini-implant anchorage and conventional molar anchorage.Methods: This comparative clinical study sample comprised 12 patients (10 females, 2 males; mean age between 16 and 22 years). The implants were placed in the maxillary and mandibular arches. Preretraction and post retraction lateral cephalograms were taken for measuring the amount, rate and anchor loss after the retraction.Results: Mean en masse retraction amounts, the rate of movement per month, and horizontal and vertical anchor loss at the maxillary implant site were 4.79 mm, 0.58 mm, 0 mm, and 0 mm, respectively. In the mandible, on implant sides were 4.66 mm, 0.56 mm, 0 mm, and 0 mm. Mean en masse retraction amounts, the rate of movement per month, and horizontal and vertical anchor loss at the maxillary conventional molar anchor side were 4.08 mm, 0.49 mm, 2.91 mm, and 1.66 mm. In the mandible, on conventional anchor sides were 3.54 mm, 0.48 mm, 3.12 mm, and 1.95 mm.Conclusion: En masse retraction had a faster rate of space closure with mini-implants as anchor units than the conventional molar anchorage preparation.

Influence of zinc borate on flame retardant and thermal properties of polyurethane elastomer composites containing huntite‐hydromagnesite mineral

SummaryThe effect of zinc borate (ZnB) was studied on the flame retardant and thermal properties of thermoplastic polyurethane containing huntite‐hydromagnesite. The flame retardant properties of thermoplastic polyurethane–based composites were investigated using limiting oxygen index, vertical burning test (UL 94), thermogravimetric analysis, and mass loss calorimeter. No remarkable effect of ZnB was observed on the flammability properties of composites. UL 94 rating did not change regardless of the added amount of ZnB, and the slight increase in limiting oxygen index value was observed at ratio of 1:1. The adjuvant effect of ZnB was observed during the mass loss calorimeter studies by increasing the barrier effect of the residue in the condensed phase and by increasing the formation of incombustible gasses in the gas phase. The highest fire performance was achieved at ratio of 1:1.

The percolation threshold and permeability evolution of ascending magmas

The development of gas permeability in magmas is a complex phenomenon that directly influences the style of a volcanic eruption. The emergence of permeability is linked to the concept of percolation threshold, which is the point beyond which gas bubbles are connected in a continuous network that allows gas escape. Measurements of the percolation threshold, however, range from ∼30 to 78 vol%. No known combination of parameters can explain such a wide range of threshold values, which affects our understanding of the relationship between percolation and permeability. We present permeability calculations on bubble-bearing rhyolitic melts that underwent experimental decompression. Samples were analyzed by X-ray microtomography to image the bubble networks in 3D. We develop a percolation threshold for magmas that depends on the bubble network characteristics of this sample set. This relationship recovers the behavior of a wide range of volcanic samples by separating permeable samples from impermeable ones with a success rate of 88%. We use this percolation threshold to propose simplified permeability relationships that rely on parameters widely used in numerical modeling of magma flow. These relationships are valid within one order of magnitude for the viscous permeability coefficient and within two orders of magnitude for the inertial coefficient. They recover the ranges of values previously covered by isolated relationships, reassembling them within a single framework. We test the implications of such unification on eruptive dynamics with a 1D, two-phase conduit flow model. This test shows that varying the percolation threshold has little influence on vertical gas loss and ascent dynamics.

Tissue Engineering Therapy for Atrophic Maxilla Using Minimally Manipulated CD90 and CD105 Bone Marrow Stem Cells: A Case Report

Bone deficiencies in the jaws of edentulous patients limit the possibility of successful placement and osseointegration of endosseous implants. Bone resorption is defined as a vertical and horizontal loss of quality and quantity in the residual bone ridges; lack of bone structure requires bone grafting procedures to enable implant placement and to improve the function, predictability, and longevity of implants. The objective of this case study was to demonstrate the feasibility of a novel cell therapy treatment for localized jaw bone defects with tissue repair cells composed of a mixture of bone marrow-derived cells, including CD90+ mesenchymal stem cells and CD105+ monocytes/macrophages, and xenograft blocks, in what would be a safe and efficacious approach to the regeneration of localized craniofacial bone defects. The use of stem cells represents an alternative that could offer improved results, better quality histologically, and greater quantity in millimeters of tissue in bone regeneration.

Survival of labial inversely impacted maxillary central incisors: A retrospective cone-beam computed tomography 2-year follow-up.

The aim of this study was to analyze the development and stability of roots and alveolar bone in orthodontically treated labial inversely impacted maxillary central incisors in a long-term follow-up by cone-beam computed tomography. Comparisons were made between the labial inversely impacted maxillary central incisors after treatment and normally erupted mature contralateral incisors. The sample consisted of 12 participants, with a mean age of 7.80±0.91years. Cone-beam computed tomography scanning data at the completion of treatment and the long-term follow-up were available for each participant.The mean length of follow-up was 24.57±4.33months. Root length, crown height, root canal width, labial/lingual alveolar bone vertical loss, and bone thickness of the impacted and contralateral incisors were measured with the SimPlant Pro program (version 13.0; Materialise Dental, Leuven, Belgium). In the follow-up, the root lengths of both the labial inversely impacted dilacerated maxillary central incisors (10.99±1.96mm) and the contralateral mature maxillary central incisors (11.65±1.37mm) were significantly longer than at posttreatment (8.37±1.74mm and 9.81±1.65mm, respectively). The root canal widths of the impacted and contralateral incisors were significantly narrower during the follow-up. The size of the angle between the long axis of the crown and apical third of the root decreased significantly. The lingual alveolar bone loss of the impacted incisors was greater than that of the contralateral incisors. The labial bone thickness at the apex of the impacted incisors increased significantly during the follow-up period. The treated labial inversely impacted maxillary central incisors had continuous and similar growth as did the mature contralateral incisors in the follow-up period. The roots had an increase in length and a change in direction of the apex, with a relatively stable condition of the surrounding alveolar bone. Neither the labial inversely impacted maxillary central incisors nor the contralateral incisors had further alveolar bone loss.