117 research outputs found

    Zygomatic Implant Survival in 9 Ectodermal Dysplasia Patients with 3.5 to 7-year Follow Up

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    Ectodermal dysplasia syndrome is a complex group of genetic disorders identified by the abnormal development of the ectodermal structures. The aim of this retrospective clinical case series report was to evaluate the outcomes of the ectodermal dysplasia syndrome patients that underwent zygomatic implant surgery. Materials and Methods: A total of 9 ectodermal dysplasia syndrome patients aged between 21 and 56 years (mean age 36.8) with severely atrophic maxilla were included in this study. All the patients were treated with a total of 19 zygomatic implants. The mean follow-up of the patients was 55 months (with a range of 44\u201384 months). The implant survival rate was evaluated as a primary outcome. The intra- and postoperative complications were evaluated as additional criteria for success. Results: The overall implant survival rate was 100% without any complications. Final or provisional prosthesis was delivered on the same day of surgery, which resulted in an improvement of the quality of life of the patients. Conclusion: According to the results of this study, zygomatic surgery can be considered as a viable and safe alternative to conventional treatment modalities for oral rehabilitation of ectodermal dysplasia syndrome patients

    Hemifacial microsomia: Case report and literature review

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    Hemifacial microsomia (HFM) is a sporadic congenital malformation of the craniofacial structures derived from the first and second branchial arches. The incidence of HFM has been reported to range from 1 in 3,0001 to 1 in 26,0002 live births, making HFM the second most common congenital malformation in the face after cleft lip and/or palate. An 11-year-old girl came at Galeazzi Institute (Milan) in January 2017. She presented left hemifacial microsomia with absence of the left ramus of mandible and the left temporomandibular joint (tmj), part of the zygomatic arch, hypoplasia of the lateral and inferior orbital bone and of the zygomatic bone. She also presented a medial canthal dystopia. She underwent to costochondral bone graft and calvaria bone graft for reconstruction of part of the mandible and the TMJ. An emi-Le Fort I, emi-Le Fort III, and sagittal segmental osteotomy of the right mandible were performed to improve the correct occlusion. Traditionally, the costochondral graft has been considered the gold standard for ramus-condyle reconstruction in the pediatric mandible when appropriate. Some studies cite growth unpredictability and ankylosis as concerns with rib. Further studies examining carefully the factors predicting graft growth, such as size of cartilage cap, surgical technique, and postoperative physiotherapy, are warranted

    Perturbation Theory for Metastable States of the Dirac Equation with Quadratic Vector Interaction

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    The spectral problem of the Dirac equation in an external quadratic vector potential is considered using the methods of the perturbation theory. The problem is singular and the perturbation series is asymptotic, so that the methods for dealing with divergent series must be used. Among these, the Distributional Borel Sum appears to be the most well suited tool to give answers and to describe the spectral properties of the system. A detailed investigation is made in one and in three space dimensions with a central potential. We present numerical results for the Dirac equation in one space dimension: these are obtained by determining the perturbation expansion and using the Pad\'e approximants for calculating the distributional Borel transform. A complete agreement is found with previous non-perturbative results obtained by the numerical solution of the singular boundary value problem and the determination of the density of the states from the continuous spectrum.Comment: 10 pages, 1 figur

    One-Dimensional Discrete Stark Hamiltonian and Resonance Scattering by Impurities

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    A one-dimensional discrete Stark Hamiltonian with a continuous electric field is constructed by extension theory methods. In absence of the impurities the model is proved to be exactly solvable, the spectrum is shown to be simple, continuous, filling the real axis; the eigenfunctions, the resolvent and the spectral measure are constructed explicitly. For this (unperturbed) system the resonance spectrum is shown to be empty. The model considering impurity in a single node is also constructed using the operator extension theory methods. The spectral analysis is performed and the dispersion equation for the resolvent singularities is obtained. The resonance spectrum is shown to contain infinite discrete set of resonances. One-to-one correspondence of the constructed Hamiltonian to some Lee-Friedrichs model is established.Comment: 20 pages, Latex, no figure

    Seismic analysis of the Roman Temple of Évora, Portugal

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    The Roman temple of Évora dates back to the 1st century AD and has undergone several changes throughout history, including various additions, which have been removed. Several archaeological studies have recently been carried out, but the structural safety of the temple is unknown. Of particular concern is the temple’s seismic resistance, as it is located in a region subjected to a moderate seismic hazard. The main purpose of this paper is to ascertain the temple’s behaviour under seismic excitation through limit analysis and discrete element analysis. Both analysis techniques will use the assumption that the structure is composed of rigid blocks connected with dry joints. Geometric information has been derived from a recent laser scanning surveying, while calibration undertaken using in-situ results from GPR and dynamic identification tests. The main results are presented and discussed in detail as well as the need for possible repair works within the framework of the ICARSAH guidelines

    Bender-Wu Formula and the Stark Effect in Hydrogen

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    We discuss a close connection between the formula of Banks, Bender, and Wu for the asymptotics of the Rayleigh-Schrödinger coefficients of the two-dimensional rotationally symmetric anharmonic oscillator and the behavior of resonances of the hydrogen Stark problem in two regimes: small field (Oppenheimer's formula) and large field (where we obtain the new results arg E → −π/3, ∣E∣ ∼α[F(lnF)^(2/3) for F, the electric field strength, going to infinity). We also announce a rigorous proof of Bender-Wu-type formulas

    Clinical outcomes of fully and partially threaded zygomatic implants in a cohort of patients with minimum 7.5-year follow-up

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    OBJECTIVE: The aim of this retrospective case series report was to evaluate the results of oral rehabilitation with extra-sinus zygomatic implant surgery with a minimum follow-up of 7.5 years. PATIENTS AND METHODS: A total of 35 patients with 87 zygomatic implants were included. The mean follow-up period of the patients was 93 months. The zygomatic implant survival and complications were evaluated as criteria for success. RESULTS: There were no implant failures. Overall success rate without complications for zygomatic implant was 88.5%. Complications developed in 4 patients (1 cutaneous fistula and 3 mucositis). According to the results on an implant basis, patients with previously failed conventional implants had greater probability of complications. Patients with quad zygomatic implants had higher incidence of complications than those with two zygomatic implants. Fully threaded implant design was associated with higher incidence of mucositis than partially threaded design. No relation was found between implant success and smoking, prosthesis type, and antagonist dentition. When conducting the analysis using the patient as unit, only the antagonist dentition showed significant difference, the worst outcome being associated with the Toronto resin prosthesis. CONCLUSIONS: Zygomatic implants can be considered as a safe alternative to conventional implant insertions and bone grafting procedures in oral rehabilitation of patients with severely atrophic maxillary bone

    Two-parametric PT-symmetric quartic family

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    We describe a parametrization of the real spectral locus of the two-parametric family of PT-symmetric quartic oscillators. For this family, we find a parameter region where all eigenvalues are real, extending the results of Dorey, Dunning, Tateo and Shin.Comment: 23 pages, 15 figure

    Land cover changes in the Brazilian Cerrado and Caatinga biomes from 1990 to 2010 based on a systematic remote sensing sampling approach

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    Abstract - The main objective of our study was to provide consistent information on land cover changes between the years 1990 and 2010 for the Cerrado and Caatinga Brazilian seasonal biomes. These areas have been overlooked in terms of land cover change assessment if compared with efforts in monitoring the Amazon rain forest. For each of the target years (1990, 2000 and 2010) land cover information was obtained through an object-based classification approach for 243 sample units (10 km × 10 km size), using (E)TM Landsat images systematically located at each full degree confluence of latitude and longitude. The images were automatically pre-processed, segmented and labelled according to the following legend: Tree Cover (TC), Tree Cover Mosaic (TCM), Other Wooded Land (OWL), Other Land Cover (OLC) and Water (W). Our results indicate the Cerrado and Caatinga biomes lost (gross loss) respectively 265,595 km2 and 89,656 km2 of natural vegetation (TC + OWL) between 1990 and 2010. In the same period, these areas also experienced gain of TC and OWL. By 2010, the percentage of natural vegetation cover remaining in the Cerrado was 47% and in the Caatinga 63%. The annual (net) rate of natural vegetation cover loss in the Cerrado slowed down from ?0.79% yr?1 to ?0.44% yr?1 from the 1990s to the 2000s, while in the Caatinga for the same periods the rate increased from ?0.19% yr?1 to ?0.44% yr?1. In summary, these Brazilian biomes experienced both loss and gains of Tree Cover and Other Wooded Land; however a continued net loss of natural vegetation was observed for both biomes between 1990 and 2010. The average annual rate of change in this period was higher in the Cerrado (?0.6% yr?1) than in the Caatinga (?0.3% yr?1)
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