WorldWideScience

Sample records for stylolite teeth geometry

  1. A new stylolite classification scheme to estimate compaction and local permeability variations

    Science.gov (United States)

    Koehn, D.; Rood, M. P.; Beaudoin, N.; Chung, P.; Bons, P. D.; Gomez-Rivas, E.

    2016-12-01

    We modeled the geometrical roughening of bedding-parallel, mainly layer-dominated stylolites in order to understand their structural evolution, to present an advanced classification of stylolite shapes and to relate this classification to chemical compaction and permeability variations at stylolites. Stylolites are rough dissolution seams that develop in sedimentary basins during chemical compaction. In the Zechstein 2 carbonate units, an important lean gas reservoir in the southern Permian Zechstein basin in Germany, stylolites influence local fluid flow, mineral replacement reactions and hence the permeability of the reservoir. Our simulations demonstrate that layer-dominated stylolites can grow in three distinct stages: an initial slow nucleation phase, a fast layer-pinning phase and a final freezing phase if the layer is completely dissolved during growth. Dissolution of the pinning layer and thus destruction of the stylolite's compaction tracking capabilities is a function of the background noise in the rock and the dissolution rate of the layer itself. Low background noise needs a slower dissolving layer for pinning to be successful but produces flatter teeth than higher background noise. We present an advanced classification based on our simulations and separate stylolites into four classes: (1) rectangular layer type, (2) seismogram pinning type, (3) suture/sharp peak type and (4) simple wave-like type. Rectangular layer type stylolites are the most appropriate for chemical compaction estimates because they grow linearly and record most of the actual compaction (up to 40 mm in the Zechstein example). Seismogram pinning type stylolites also provide good tracking capabilities, with the largest teeth tracking most of the compaction. Suture/sharp peak type stylolites grow in a non-linear fashion and thus do not record most of the actual compaction. However, when a non-linear growth law is used, the compaction estimates are similar to those making use of the

  2. Compaction and local fluid flow variations estimate through a new stylolite classification

    Science.gov (United States)

    Koehn, Daniel; Beaudoin, Nicolas

    2017-04-01

    Pressure solution is a mechanism commonly affecting sedimentary rocks, developing rough surfaces called bedding-parallel stylolites (BPS) when the stress originates from strata burial. In the Zechstein 2 carbonate units, an important lean gas reservoir in the southern Permian Zechstein basin in Germany, stylolites influence local fluid flow, mineral replacement reactions and hence the permeability of the reservoir. The geometrical growth of the roughening of layer dominated BPS has been modeled numerically in order to understand their structural evolution. Our simulations demonstrate that layer-dominated stylolites can grow in three distinct stages: an initial slow nucleation phase, a fast layer pinning phase and a final freezing phase if the layer is completely dissolved during growth. Dissolution of the pinning layer and thus destruction of the stylolite's compaction tracking capabilities is a function of the background noise in the rock and the dissolution rate of the layer itself. Low background noise needs a slower dissolving layer for pinning to be successful but produces flatter teeth than higher background noise. From comparison between roughness as resulting from the models and as observed in nature, we present a comprehensive classification of BPS that bound the final morphology of a stylolite to its impact on chemical compaction and on local permeability variation. BPS falls into four classes: (1) rectangular layer type, (2) seismogram pinning type, (3) suture/sharp peak type and (4) simple wave-like type. Our results show that the capability of a stylolite to consistently track the amount of chemical compaction is dependent on the linearity of their growth law. As a result, rectangular layer type stylolites are the most appropriate for chemical compaction estimates because they grow linearly and record most of the actual compaction, Seismogram pinning type stylolites also provide good tracking capabilities, with the largest teeth tracking most of the

  3. Potential degradation mechanisms of stylolitic limestones

    Science.gov (United States)

    Aly, Nevin; Török, Ákos; Aguilar Sanchez, Asel Maria; Wangler, Timothy

    2017-04-01

    Stylolites are irregular rough surfaces formed due to the pressure-solution process and commonly developed in carbonate stones. Stylolite formation is usually accompanied by the accumulation of insoluble residues i.e. organic matter, oxides and clays on the stylolitic surfaces. The amount and the type of these clays may play a significant role in the deterioration of the host stone. This study presents the characterization of various stylolitic limestones containing different amounts of clays and used extensively as building cladding and decorative stones in Israel and in Hungary. The first case study focuses on two lithotypes from Israel, both of them are biocalcirudite-calcarenite with high amount of bioclasts. Abundance of open stylolites filled partially with organic matter and minor amounts of clays exist in the first lithotype with cream colour. The second lithotype has grey colour and contains organic matter and pyrite dispersed throughout the stone and more concentrated within the stylolites along with clay and dolomite crystal. Both lithotypes exhibit signs of decay just after a few years of exposure. The first studied Hungarian limestone is a red Jurassic carbonate (ammonitico rosso type) that was formed in pelagic marine environment. This wackestone contains abundant pelagic microfossils. The limestone has been used from Roman period in Central Europe in Hungary, Romania and Poland. The stylolites are seen as darker bedding parallel seams containing minor amounts of clay and hematite. Small amount of clay is also found in isolated nodules. The second Hungarian lithotype is also a Jurassic limestone which contains less clay than the previous one. This yellowish-white limestone is strongly cemented and contains red intersecting stylolites that do not follow the bedding planes or stratification. The main aim of this study is to understand and evaluate the damage mechanism of different stylolitic limestones. Samples were exposed to multiple thermal and wet

  4. Exhumation and stress history in the sedimentary cover during Laramide thick-skinned tectonics assessed by stylolite roughness analysis.

    Science.gov (United States)

    Beaudoin, Nicolas; Lacombe, Olivier; David, Marie-Eléonore; Koehn, Daniel; Coltier, Robin

    2017-04-01

    Basement-involvement in shortening in forelands has a strong impact on the overlying sedimentary cover. The basement influences namely the geometry of folds and structures, the stress evolution and the nature and pathways for fluid migrations. However, these influences are poorly documented in context where the basement/cover interface is shallow (Sevier-Laramide deformation at the front of the Rocky Mountains, in the Bighorn Basin (Wyoming, USA). Stylolite populations have been considered as part of an extensive microstructure investigation including also fractures, striated microfaults and calcite twins in key major structures such as the Sheep Mountain Anticline, the Rattlesnake Mountain Anticline, and the Bighorn Mountains Arch. Stylolite recognized in the field are clearly related to successive stages of deformation of the sedimentary cover, including fold development. We further apply a newly developed roughness analysis of pressure-solution stylolites which grant access (1) to the magnitude of the vertical principal stress, hence the maximum burial depth of the strata based on sedimentary stylolites, (2) to the principal stress orientations and regimes based on tectonic stylolites and (3) ultimately to the complete stress tensor when sedimentary and tectonic stylolites can be considered coeval. This approach was then coupled to mechanical properties of main competent formations exposed in the basin. Results of stylolite paleopiezometry, compared and combined to existing paleostress estimates from calcite twins and to exhumation reconstruction from low-temperature thermochronology, unravel the potential of the method to refine the structural history at the structure- and basin-scale. On top of the advances this case study adds to the methodology, the quantified reconstruction of stress-exhumation evolution in such a broken-foreland context offers a unique opportunity to discuss how thick-skinned tectonics impacts stress distribution in the sedimentary cover.

  5. Compaction of porous rock by dissolution on discrete stylolites

    DEFF Research Database (Denmark)

    Angheluta, Luiza; Mathiesen, Joachim; Aharonov, Einat

    2012-01-01

    Compaction of sedimentary porous rock by dissolution and precipitation is a complex deformation mechanism, that is often localized on stylolites and pressure solution seams. We consider a one-dimensional model of compaction near a thin clay-rich stylolite embedded in a porous rock. Under the assu......Compaction of sedimentary porous rock by dissolution and precipitation is a complex deformation mechanism, that is often localized on stylolites and pressure solution seams. We consider a one-dimensional model of compaction near a thin clay-rich stylolite embedded in a porous rock. Under...... the assumption that the clay enhances solubility, the model predicts a reactive transport away from the clay layer followed by pore cementation. The evolution of the porosity, reactant transport, and compaction rate are studied as functions of model parameters and shown to reach a stationary state. We find good...

  6. Teeth.

    Science.gov (United States)

    Billings, Ronald J; Berkowitz, Robert J; Watson, Gene

    2004-04-01

    Common environmental chemicals, drugs, or physical agents can adversely affect human teeth during their embryonic development and after their eruption into the oral cavity. One of the more common elemental toxicants is lead. Teeth are known to accumulate lead during their development. Both animal and human studies have shown that teeth with high lead levels are generally more susceptible to dental caries. Similarly, although inorganic fluorides have long been recognized for their potential to prevent dental caries, exposure to excessive amounts of fluoride when enamel is forming often leads to a type of enamel hypoplasia referred to as dental fluorosis or mottled enamel. Teratogenic agents, such as tetracyclines, a class of antibiotic drugs commonly administered to infants and children, will often result in the discoloration of tooth enamel when prescribed during tooth development. It has recently been suggested that childhood exposure to passive smoking increases the risk for dental caries. Environmental tobacco smoke has previously been linked to periodontal disease in adults. However, this is the first report of an association between passive tobacco smoke and increased susceptibility to dental caries. Last, an often-overlooked source of damage to teeth among all age groups after their eruption into the oral cavity is physical trauma from a variety of sources, especially sports-related injuries. Epidemiologic data suggest that up to one third of all dental injuries are sports related.

  7. Photon dose conversion coefficients for the human teeth in standard irradiation geometries

    Energy Technology Data Exchange (ETDEWEB)

    Ulanovsky, A.; Wieser, A.; Zankl, M.; Jacob, P.

    2005-07-01

    Photon dose conversion coefficients for the human tooth materials are computed in energy range from 0.01 to 10 MeV by the Monte Carlo method. The voxel phantom Golem of the human body with newly defined tooth region and a modified version of the EGS4 code have been used to compute the coefficients for 30 tooth cells with different locations and materials. The dose responses are calculated for cells representing buccal and lingual enamel layers. The computed coefficients demonstrate a strong dependence on energy and geometry of the radiation source and a weaker dependence on location of the enamel voxels. For isotropic and rotational radiation fields the enamel dose does not show a significant dependence on tooth sample locations. The computed coefficients are used to convert from absorbed dose in teeth to organ dose or to integral air kerma. Examples of integral conversion factors from enamel dose to air kerma are given for several photon fluences specific for the Mayak reprocessing plant in Russia. The integral conversion factors are strongly affected by the energy and angular distributions of photon fluence, which are important characteristics of an exposure scenario for reconstruction of individual occupational doses. (orig.)

  8. Changes of scaling relationships in an evolving population: The example of "sedimentary" stylolites

    Science.gov (United States)

    Peacock, D. C. P.; Korneva, I.; Nixon, C. W.; Rotevatn, A.

    2017-03-01

    Bed-parallel (;sedimentary;) stylolites are used as an example of a population that evolves by the addition of new components, their growth and their merger. It is shown that this style of growth controls the changes in the scaling relationships of the population. Stylolites tend to evolve in carbonate rocks through time, for example by compaction during progressive burial. The evolution of a population of stylolites, and their likely effects on porosity, are demonstrated using simple numerical models. Starting with a power-law distribution, the adding of new stylolites, the increase in their amplitudes and their merger decrease the slope of magnitude versus cumulative frequency of the population. The population changes to a non-power-law distribution as smaller stylolites merge to form larger stylolites. The results suggest that other populations can be forward- or backward-modelled, such as fault lengths, which also evolve by the addition of components, their growth and merger. Consideration of the ways in which populations change improves understanding of scaling relationships and vice versa, and would assist in the management of geofluid reservoirs.

  9. Geometry

    CERN Document Server

    Pedoe, Dan

    1988-01-01

    ""A lucid and masterly survey."" - Mathematics Gazette Professor Pedoe is widely known as a fine teacher and a fine geometer. His abilities in both areas are clearly evident in this self-contained, well-written, and lucid introduction to the scope and methods of elementary geometry. It covers the geometry usually included in undergraduate courses in mathematics, except for the theory of convex sets. Based on a course given by the author for several years at the University of Minnesota, the main purpose of the book is to increase geometrical, and therefore mathematical, understanding and to he

  10. Geometry

    Indian Academy of Sciences (India)

    of geometry he completely changed our way of thinking. Later geometers were to spend entire lifetimes trying ... dimensions up to and including three it is difficult to think of dimensions beyond except abstractly -in one's .... form I. gij ai aj is positive for any collection of numbers. (aI, ... , an). Moreover, the given form can easily ...

  11. Geometri

    DEFF Research Database (Denmark)

    Byg din egen boomerang, kast den, se den flyve, forstå hvorfor og hvordan den vender tilbage, og grib den. Det handler om opdriften på vingerne når du flyver, men det handler også og allermest om den mærkværdige gyroskop-effekt, du bruger til at holde balancen, når du kører på cykel. Vi vil bruge...... matematik, geometri, og fysik til at forstå, hvad det er, der foregår....

  12. New geometry and technology of face-gear forming with circle line of teeth on CNC milling machine

    Directory of Open Access Journals (Sweden)

    P. Frąckowiak

    2012-01-01

    Full Text Available Different types of geometric models of face-gear with circle line of teeth have been shown in the paper. Generation of a new geometrical of a face-gear is performed on CNC milling machine. The basic direction of the development geometrical of a face-gear and technology is in the search of new trends and methods focused on improving the quality of products, shortening the production cycles, their mechanizations, automation and implementation of a high-precision technology.

  13. Estimates of chemical compaction and maximum burial depth from bedding parallel stylolites

    Science.gov (United States)

    Gasparrini, Marta; Beaudoin, Nicolas; Lacombe, Olivier; David, Marie-Eleonore; Youssef, Souhail; Koehn, Daniel

    2017-04-01

    Chemical compaction is a diagenetic process affecting sedimentary series during burial that develops rough dissolution surfaces named Bedding Parallel Stylolites (BPS). BPS are related to the dissolution of important rock volumes and can lead to porosity reduction around them due to post-dissolution cementation. Our understanding of the effect of chemical compaction on rock volume and porosity evolution during basin burial is however too tight yet to be fully taken into account in basin models and thermal or fluid-flow simulations. This contribution presents a novel and multidisciplinary approach to quantify chemical compaction and to estimate maximum paleodepth of burial, applied to the Dogger carbonate reservoirs from the Paris Basin sub-surface. This succession experienced a relatively simple burial history (nearly continuous burial from Upper Jurassic to Upper Cretaceous, followed by a main uplift phase), and mainly underwent normal overburden (inducing development of BPS), escaping major tectonic stress episodes. We considered one core from the depocentre and one from the eastern margin of the basin in the same stratigraphic interval (Bathonian Sup. - Callovian Inf.; restricted lagoonal setting), and analysed the macro- and micro-facies to distinguish five main depositional environments. Type and abundance of BPS were continuously recorded along the logs and treated statistically to obtain preliminary rules relying the occurrence of the BPS as a function of the contrasting facies and burial histories. The treatment of high resolution 2D images allowed the identification and separation of the BPS to evaluate total stylolitization density and insoluble thickness as an indirect measure of the dissolved volume, with respect to the morphology of the BPS considered. Based on the morphology of the BPS roughness, we used roughness signal analysis method to reconstruct the vertical paleo-stress (paleo-depth) recorded by the BPS during chemical compaction. The

  14. Your Teeth

    Science.gov (United States)

    ... you make the "l" sound. Treating Teeth Kindly Brushing your teeth with fluoride toothpaste is your best bet when it comes to keeping your teeth in tip-top shape . Try to brush after eating or at least twice a day. It's especially important to brush before bedtime. The best way to ...

  15. 6. Teeth

    African Journals Online (AJOL)

    The delayed exfoliation of primary teeth among children is a common and frequent dental problem whose most sited cause is misalignment of the crown of the successional permanent tooth with the root apex of the primary tooth. Treatment is often extraction of the over retained primary teeth and reassurance of the guardian ...

  16. Wisdom Teeth Management

    Science.gov (United States)

    Wisdom Teeth Management Wisdom teeth, or third molars, are the last teeth to develop and appear in your mouth. They come ... of third molars, disease status, and to suggest management options ranging from removal to a monitored retention ...

  17. Algebraic Geometry

    CERN Document Server

    Holme, Audun

    1988-01-01

    This volume presents selected papers resulting from the meeting at Sundance on enumerative algebraic geometry. The papers are original research articles and concentrate on the underlying geometry of the subject.

  18. Bilateral tuberculate supernumerary teeth.

    Science.gov (United States)

    Eigbobo, Joycelyn Odegua; Osagbemiro, Babatope Bamidele

    2011-05-16

    Supernumerary teeth are teeth in excess of the normal series occurring in any region of the dental arch. They are located mostly in the anterior maxillary region and are classified according to their location and morphology. The tuberculate type of supernumerary tooth possesses more than one cusp or tubercle (barrel shaped). It is rare to find bilateral tuberculate supernumerary teeth in the premaxillary region and when found they rarely erupt. This report describes a 13-year-old boy with erupted palatally placed bilateral tuberculate supernumerary teeth. The presence of these supernumerary teeth led to the labial displacement and rotations of the anterior maxillary teeth. The treatment involved extraction of the supernumerary teeth and a referral for orthodontic management of the crowding, displacement and rotations. The occurrence of erupted palatally placed tuberculate anterior teeth in this case is a rare experience. However, the associated orthodontic problems are within familiar spectrum.

  19. Differential geometry

    CERN Document Server

    Guggenheimer, Heinrich W

    1977-01-01

    This is a text of local differential geometry considered as an application of advanced calculus and linear algebra. The discussion is designed for advanced undergraduate or beginning graduate study, and presumes of readers only a fair knowledge of matrix algebra and of advanced calculus of functions of several real variables. The author, who is a Professor of Mathematics at the Polytechnic Institute of New York, begins with a discussion of plane geometry and then treats the local theory of Lie groups and transformation groups, solid differential geometry, and Riemannian geometry, leading to a

  20. Molecular geometry

    CERN Document Server

    Rodger, Alison

    1995-01-01

    Molecular Geometry discusses topics relevant to the arrangement of atoms. The book is comprised of seven chapters that tackle several areas of molecular geometry. Chapter 1 reviews the definition and determination of molecular geometry, while Chapter 2 discusses the unified view of stereochemistry and stereochemical changes. Chapter 3 covers the geometry of molecules of second row atoms, and Chapter 4 deals with the main group elements beyond the second row. The book also talks about the complexes of transition metals and f-block elements, and then covers the organometallic compounds and trans

  1. About Kids' Teeth

    Science.gov (United States)

    ... gums and teeth cleaned – and it will make tooth brushing easier later on. Once your child’s teeth start to come into the mouth, brush using ... of a grain of rice. Brush your children’s teeth until they are able ... 8. Then, supervise their brushing to make sure they brush thoroughly 2min2x (2 ...

  2. Tolerance Geometry.

    Science.gov (United States)

    Roberts, Fred S.

    The author cites work on visual perception which indicates that in order to study perception it is necessary to replace such classical geometrical notions as betweeness, straightness, perpendicularity, and parallelism with more general concepts. The term tolerance geometry is used for any geometry when primitive notions are obtained from the…

  3. Architectural geometry

    KAUST Repository

    Pottmann, Helmut

    2014-11-26

    Around 2005 it became apparent in the geometry processing community that freeform architecture contains many problems of a geometric nature to be solved, and many opportunities for optimization which however require geometric understanding. This area of research, which has been called architectural geometry, meanwhile contains a great wealth of individual contributions which are relevant in various fields. For mathematicians, the relation to discrete differential geometry is significant, in particular the integrable system viewpoint. Besides, new application contexts have become available for quite some old-established concepts. Regarding graphics and geometry processing, architectural geometry yields interesting new questions but also new objects, e.g. replacing meshes by other combinatorial arrangements. Numerical optimization plays a major role but in itself would be powerless without geometric understanding. Summing up, architectural geometry has become a rewarding field of study. We here survey the main directions which have been pursued, we show real projects where geometric considerations have played a role, and we outline open problems which we think are significant for the future development of both theory and practice of architectural geometry.

  4. Projective geometry

    CERN Document Server

    Faulkner, T Ewan

    2006-01-01

    This text explores the methods of the projective geometry of the plane. Some knowledge of the elements of metrical and analytical geometry is assumed; a rigorous first chapter serves to prepare readers. Following an introduction to the methods of the symbolic notation, the text advances to a consideration of the theory of one-to-one correspondence. It derives the projective properties of the conic and discusses the representation of these properties by the general equation of the second degree. A study of the relationship between Euclidean and projective geometry concludes the presentation. Nu

  5. Differential geometry

    CERN Document Server

    Graustein, William C

    2006-01-01

    This first course in differential geometry presents the fundamentals of the metric differential geometry of curves and surfaces in a Euclidean space of three dimensions. Written by an outstanding teacher and mathematician, it explains the material in the most effective way, using vector notation and technique. It also provides an introduction to the study of Riemannian geometry.Suitable for advanced undergraduates and graduate students, the text presupposes a knowledge of calculus. The first nine chapters focus on the theory, treating the basic properties of curves and surfaces, the mapping of

  6. Beautiful geometry

    CERN Document Server

    Maor, Eli

    2014-01-01

    If you've ever thought that mathematics and art don't mix, this stunning visual history of geometry will change your mind. As much a work of art as a book about mathematics, Beautiful Geometry presents more than sixty exquisite color plates illustrating a wide range of geometric patterns and theorems, accompanied by brief accounts of the fascinating history and people behind each. With artwork by Swiss artist Eugen Jost and text by acclaimed math historian Eli Maor, this unique celebration of geometry covers numerous subjects, from straightedge-and-compass constructions to intriguing configur

  7. Information geometry

    CERN Document Server

    Ay, Nihat; Lê, Hông Vân; Schwachhöfer, Lorenz

    2017-01-01

    The book provides a comprehensive introduction and a novel mathematical foundation of the field of information geometry with complete proofs and detailed background material on measure theory, Riemannian geometry and Banach space theory. Parametrised measure models are defined as fundamental geometric objects, which can be both finite or infinite dimensional. Based on these models, canonical tensor fields are introduced and further studied, including the Fisher metric and the Amari-Chentsov tensor, and embeddings of statistical manifolds are investigated. This novel foundation then leads to application highlights, such as generalizations and extensions of the classical uniqueness result of Chentsov or the Cramér-Rao inequality. Additionally, several new application fields of information geometry are highlighted, for instance hierarchical and graphical models, complexity theory, population genetics, or Markov Chain Monte Carlo. The book will be of interest to mathematicians who are interested in geometry, inf...

  8. Algebraic geometry

    CERN Document Server

    Lefschetz, Solomon

    2005-01-01

    An introduction to algebraic geometry and a bridge between its analytical-topological and algebraical aspects, this text for advanced undergraduate students is particularly relevant to those more familiar with analysis than algebra. 1953 edition.

  9. Subtracted geometry

    Science.gov (United States)

    Saleem, Zain Hamid

    In this thesis we study a special class of black hole geometries called subtracted geometries. Subtracted geometry black holes are obtained when one omits certain terms from the warp factor of the metric of general charged rotating black holes. The omission of these terms allows one to write the wave equation of the black hole in a completely separable way and one can explicitly see that the wave equation of a massless scalar field in this slightly altered background of a general multi-charged rotating black hole acquires an SL(2, R) x SL(2, R) x SO(3) symmetry. The "subtracted limit" is considered an appropriate limit for studying the internal structure of the non-subtracted black holes because new 'subtracted' black holes have the same horizon area and periodicity of the angular and time coordinates in the near horizon regions as the original black hole geometry it was constructed from. The new geometry is asymptotically conical and is physically similar to that of a black hole in an asymptotically confining box. We use the different nice properties of these geometries to understand various classically and quantum mechanically important features of general charged rotating black holes.

  10. Analytic geometry

    CERN Document Server

    Burdette, A C

    1971-01-01

    Analytic Geometry covers several fundamental aspects of analytic geometry needed for advanced subjects, including calculus.This book is composed of 12 chapters that review the principles, concepts, and analytic proofs of geometric theorems, families of lines, the normal equation of the line, and related matters. Other chapters highlight the application of graphing, foci, directrices, eccentricity, and conic-related topics. The remaining chapters deal with the concept polar and rectangular coordinates, surfaces and curves, and planes.This book will prove useful to undergraduate trigonometric st

  11. Vector geometry

    CERN Document Server

    Robinson, Gilbert de B

    2011-01-01

    This brief undergraduate-level text by a prominent Cambridge-educated mathematician explores the relationship between algebra and geometry. An elementary course in plane geometry is the sole requirement for Gilbert de B. Robinson's text, which is the result of several years of teaching and learning the most effective methods from discussions with students. Topics include lines and planes, determinants and linear equations, matrices, groups and linear transformations, and vectors and vector spaces. Additional subjects range from conics and quadrics to homogeneous coordinates and projective geom

  12. Malocclusion of teeth

    Science.gov (United States)

    ... stabilize the jaw bone. It is important to brush and floss your teeth every day and have regular visits to a general dentist. Plaque builds up on braces and may permanently mark teeth or cause tooth decay if it is not properly removed. You ...

  13. Architectural geometry

    NARCIS (Netherlands)

    Pottmann, Helmut; Eigensatz, Michael; Vaxman, A.; Wallner, Johannes

    2015-01-01

    Around 2005 it became apparent in the geometry processing community that freeform architecture contains many problems of a geometric nature to be solved, and many opportunities for optimization which however require geometric understanding. This area of research, which has been called architectural

  14. Geometry VI

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 8. Geometry VI - Space-the Final Frontier. Kapil H Paranjape. Series Article Volume 1 Issue 8 August 1996 pp 28-33. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/001/08/0028-0033 ...

  15. Geometry -----------~--------------RESONANCE

    Indian Academy of Sciences (India)

    From a different perspective artists had all along pointed out that parallel lines do meet at the horizon (Figure 1). In fact all pairs of coplanar lines meet and parallel lines .... A more advanced treatment can be found in this book. D Hilbert and S Cohn-Vossen. Geometry and the Imagination. Chelsea, NY,. USA. 1952. A difficult ...

  16. Supernumerary teeth in clinical practice

    OpenAIRE

    Anna K. Szkaradkiewicz; Tomasz M. Karpiński

    2011-01-01

    Introduction: Hyperdontia is the condition of having supernumerary teeth, or teeth which appear in addition to the regular number of teeth. The prevalence rates of supernumerary teeth in the permanent dentition amounts 0.1-6.9%, and in deciduous dentition 0.4-0.8%. The presence of supernumerary teeth can be found in everyday dental practice. Case presentation: We describe 3 cases of patients with supernumerary teeth. First patient had supernumerary lateral incisor 12s, second - premolar fu...

  17. Syndromes with supernumerary teeth.

    Science.gov (United States)

    Lubinsky, Mark; Kantaputra, Piranit Nik

    2016-10-01

    While most supernumerary teeth are idiopathic, they can be associated with a number of Mendelian syndromes. However, this can also be a coincidental finding, since supernumerary teeth occur in 6% or more of the normal population. To better define this relationship, we analyzed the evidence for specific associations. We excluded conditions with a single affected patient reported, supernumerary teeth adjacent to clefts or other forms of alveolar disruption (as secondary rather than primary findings), and natal teeth, which can involve premature eruption of a normal tooth. Since, the cause of supernumerary teeth shows considerable heterogeneity, certain findings are less likely to be coincidental, such as five or more supernumerary teeth in a single patient, or locations outside of the premaxilla. We found only eight genetic syndromes with strong evidence for an association: cleidocranial dysplasia; familial adenomatous polyposis; trichorhinophalangeal syndrome, type I; Rubinstein-Taybi syndrome; Nance-Horan syndrome; Opitz BBB/G syndrome; oculofaciocardiodental syndrome; and autosomal dominant Robinow syndrome. There is also suggestive evidence of an association with two uncommon disorders, Kreiborg-Pakistani syndrome (craniosynostosis and dental anomalies), and insulin-resistant diabetes mellitus with acanthosisnigricans. An association of a Mendelian disorder with a low frequency manifestation of supernumerary teeth is difficult to exclude without large numbers, but several commonly cited syndromes lacked evidence for clear association, including Hallermann-Streiff syndrome, Fabry disease, Ehlers-Danlos syndrome, Apert and Crouzon syndromes, Zimmermann-Laband syndrome, and Ellis-van Creveld syndrome. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  18. Riemannian geometry

    CERN Document Server

    Petersen, Peter

    2016-01-01

    Intended for a one year course, this text serves as a single source, introducing readers to the important techniques and theorems, while also containing enough background on advanced topics to appeal to those students wishing to specialize in Riemannian geometry. This is one of the few Works to combine both the geometric parts of Riemannian geometry and the analytic aspects of the theory. The book will appeal to a readership that have a basic knowledge of standard manifold theory, including tensors, forms, and Lie groups. Important revisions to the third edition include: a substantial addition of unique and enriching exercises scattered throughout the text; inclusion of an increased number of coordinate calculations of connection and curvature; addition of general formulas for curvature on Lie Groups and submersions; integration of variational calculus into the text allowing for an early treatment of the Sphere theorem using a proof by Berger; incorporation of several recent results about manifolds with posit...

  19. Geometrie coniugate

    Directory of Open Access Journals (Sweden)

    Leonardo Paris

    2012-06-01

    Full Text Available Lo studio degli ingranaggi si basa sulle geometrie coniugate in cui due curve o due superfici si mantengono costantemente in contatto pur se in movimento reciproco. La teoria geometrica degli ingranaggi fino alla fine del XIX secolo era uno dei molteplici rami nelle applicazioni della Geometria Descrittiva. Lo studio si basa sulla conoscenza delle principali proprietà delle curve piane e gobbe e delle loro derivate. La specificità del tema è che queste geometrie nel momento in cui si devono relazionare con le loro coniugate, devono rispettare dei vincoli che altrimenti non avrebbero. Si vuole evidenziare attraverso casi concreti il ruolo della geometria descrittiva nel passaggio dal teorico al pratico riproponendo in chiave informatica, temi e procedure di indagine spesso passati in secondo piano se non addirittura dimenticati.

  20. Application of Analytical Geometry to the

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 18; Issue 9. Application of Analytical Geometry to the Form of Gear Teeth. V G A Goss. General Article Volume 18 Issue 9 September 2013 pp 817-831. Fulltext. Click here to view fulltext PDF. Permanent link:

  1. Management of supernumerary teeth

    Science.gov (United States)

    Parolia, Abhishek; Kundabala, M; Dahal, Marisha; Mohan, Mandakini; Thomas, Manuel S

    2011-01-01

    Supernumerary paramolars are the rare anomalies of the maxillofacial complex. These are more common in the maxilla than in the mandible. This article reviews the etiology, frequency, classification, complications, diagnosis and management of supernumerary teeth (bilateral maxillary paramolars) PMID:22025821

  2. Impacted Wisdom Teeth

    Science.gov (United States)

    ... Edition. http://www.merckmanuals.com/professional/dental_disorders/periodontal_disorders/gingivitis.html?qt=Wisdom%20teeth&alt=sh. ... and newsletters from Mayo Clinic. The Mayo Clinic Diet Online Learn the science behind a happy mind ...

  3. ESTHETICS IN PRIMARY TEETH

    OpenAIRE

    Mathew Renu Ann

    2013-01-01

    Dental esthetics is an integral part of facial esthetics. Esthetic problems in childhood and adolescence can have a significant effect on psychosocial development and interaction with peers. Esthetic restoration of primary anterior teeth can be especially challenging due to the small size of the teeth, close proximity of pulp to tooth surface, relatively thin enamel and surface area for bonding, issues related to child behavior and finally cost of the treatment. The advent of different techni...

  4. Differential geometry

    CERN Document Server

    Ciarlet, Philippe G

    2007-01-01

    This book gives the basic notions of differential geometry, such as the metric tensor, the Riemann curvature tensor, the fundamental forms of a surface, covariant derivatives, and the fundamental theorem of surface theory in a selfcontained and accessible manner. Although the field is often considered a classical one, it has recently been rejuvenated, thanks to the manifold applications where it plays an essential role. The book presents some important applications to shells, such as the theory of linearly and nonlinearly elastic shells, the implementation of numerical methods for shells, and

  5. Spinor Geometry

    Science.gov (United States)

    Nicolaidis, A.; Kiosses, V.

    2012-09-01

    It has been proposed that quantum mechanics and string theory share a common inner syntax, the relational logic of C. S. Peirce. Along this line of thought we consider the relations represented by spinors. Spinor composition leads to the emergence of Minkowski space-time. Inversely, the Minkowski space-time is istantiated by the Weyl spinors, while the merger of two Weyl spinors gives rise to a Dirac spinor. Our analysis is applied also to the string geometry. The string constraints are represented by real spinors, which create a parametrization of the string worldsheet identical to the Enneper-Weierstass representation of minimal surfaces. Further, a spinorial study of the AdS3 space-time reveals a Hopf fibration AdS3 → AdS2. The conformal symmetry inherent in AdS3 is pointed out. Our work indicates the hidden ties between logic-quantum mechanics-string theory-geometry and vindicates the Wheeler's proposal of pregeometry as a large network of logical propositions.

  6. Supernumerary teeth in clinical practice

    Directory of Open Access Journals (Sweden)

    Anna K. Szkaradkiewicz

    2011-07-01

    Full Text Available Introduction: Hyperdontia is the condition of having supernumerary teeth, or teeth which appear in addition to the regular number of teeth. The prevalence rates of supernumerary teeth in the permanent dentition amounts 0.1-6.9%, and in deciduous dentition 0.4-0.8%. The presence of supernumerary teeth can be found in everyday dental practice.Case presentation: We describe 3 cases of patients with supernumerary teeth. First patient had supernumerary lateral incisor 12s, second - premolar fused, multicuspid, supernumerary deciduous tooth 64s of having several interconnected roots, and third - erupted odontoma between teeth 13 and 14. In all cases treatment involved the removal of the supernumerary tooth.Conclusions: The decision on proceeding with the supernumerary teeth should be based on the full clinical picture and interview. Early diagnosis and removal of supernumerary teeth allow to avoid or reduce possible complications.

  7. Estimating Gear Teeth Stiffness

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2013-01-01

    The estimation of gear stiffness is important for determining the load distribution between the gear teeth when two sets of teeth are in contact. Two factors have a major influence on the stiffness; firstly the boundary condition through the gear rim size included in the stiffness calculation...... and secondly the size of the contact. In the FE calculation the true gear tooth root profile is applied. The meshing stiffness’s of gears are highly non-linear, it is however found that the stiffness of an individual tooth can be expressed in a linear form assuming that the contact length is constant....

  8. Brushing Your Child's Teeth

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000769.htm Brushing Your Child's Teeth To use the sharing features on this page, ... M. Editorial team. Related MedlinePlus Health Topics ... among the first to achieve this important distinction for online health information and services. Learn ...

  9. Complex analysis and geometry

    CERN Document Server

    Silva, Alessandro

    1993-01-01

    The papers in this wide-ranging collection report on the results of investigations from a number of linked disciplines, including complex algebraic geometry, complex analytic geometry of manifolds and spaces, and complex differential geometry.

  10. Non-Riemannian geometry

    CERN Document Server

    Eisenhart, Luther Pfahler

    2005-01-01

    This concise text by a prominent mathematician deals chiefly with manifolds dominated by the geometry of paths. Topics include asymmetric and symmetric connections, the projective geometry of paths, and the geometry of sub-spaces. 1927 edition.

  11. Teeth discoloration during orthodontic treatment.

    Science.gov (United States)

    Baik, Un-Bong; Kim, Hoon; Chae, Hwa-Sung; Myung, Ji-Yun; Chun, Youn-Sic

    2017-09-01

    Teeth discoloration is a rare orthodontic complication. The aim of this study was to report the clinical progression of discoloration during orthodontic treatment. Discolored teeth, detected during orthodontic treatment between January 2003 and December 2012 by a single dentist using similar techniques and appliances, were analyzed. The total number of teeth that showed discoloration was 28. Progression of discoloration was evaluated in only 24 teeth that were observed without any treatment. During the observation period, the discoloration "improved" in 8 of the 24 teeth (33.3%) and was "maintained" in 16 (66.6%). The electric pulp test performed at the time of initial detection of discoloration showed 14.3% positivity, which improved to 21.4% at the final follow-up. None of the initial and final follow-up radiographic findings showed any abnormalities. When teeth discoloration is detected during orthodontic treatment, observation as an initial management is recommended over immediate treatments.

  12. Classical music and the teeth.

    Science.gov (United States)

    Eramo, Stefano; Di Biase, Mary Jo; De Carolis, Carlo

    2013-01-01

    Teeth and their pathologies are frequent themes in classical music. The teeth have inspired popular songwriters such as Thomas Crecquillon, Carl Loewe, Amilcare Ponchielli & Christian Sinding; as well as composers whose works are still played all over the world, such as Robert Schumann and Jacques Offenbach. This paper examines several selections in which the inspiring theme is the teeth and the pain they can cause, from the suffering of toothache, to the happier occasion of a baby's first tooth.

  13. [Multiple supernumerary teeth: a case report].

    Science.gov (United States)

    Chen, Jun; Zhang, Qing-Fu; Liu, Guo-Qin; Zhao, Hai-Jun; Zhang, Xin-Hai

    2010-02-01

    Supernumerary teeth is one of the dysplasia that the number of the teeth are more than physical number. Most cases of reports were with 1-2 supernumerary teeth and rare cases were with more than 3 supernumerary teeth. A 17-year old female patient of 7 impacted supernumerary teeth were found because of toothache of premolar caused by impacted supernumerary teeth and were treated by extraction of impacted supernumerary teeth.

  14. Notes on noncommutative geometry

    OpenAIRE

    Nikolaev, Igor

    2015-01-01

    The book covers basics of noncommutative geometry and its applications in topology, algebraic geometry and number theory. A brief survey of main parts of noncommutative geometry with historical remarks, bibliography and a list of exercises is attached. Our notes are intended for the graduate students and faculty with interests in noncommutative geometry; they can be read by non-experts in the field.

  15. 234U/238U Disequilibrium along stylolitic discontinuities in deep Mesozoic limestone formations of the Eastern Paris basin: evidence for discrete uranium mobility over the last 1–2 million years

    Directory of Open Access Journals (Sweden)

    P. Deschamps

    2004-01-01

    Full Text Available The (234U/238 equilibrium state of borehole core samples from the deep, low-permeability limestone formations surrounding the target argilite layer of the Meuse/Haute-Marne experimental site of the French agency for nuclear waste management -ANDRA- (Agence nationale pour la gestion des déchets radioactifs was examined to improve understanding of naturally occurring radionuclide behaviour in such geological settings. Highly precise, accurate MC-ICP-MS measurements of the (234U/238U activity ratio show that limestone samples characterised by pressure dissolution structures (stylolites or dissolution seams display systematic (234U/238U disequilibria, while the pristine carbonate samples remain in the secular equilibrium state. The systematic feature is observed throughout the zones marked by pressure dissolution structures: (i the material within the seams shows a deficit of 234U over 238U ((234U/238U down to 0.80 and (ii the surrounding carbonate matrix is characterised by an activity ratio greater than unity (up to 1.05. These results highlight a centimetric-scale uranium remobilisation in the limestone formations along these sub-horizontal seams. Although their nature and modalities are not fully understood, the driving processes responsible for these disequilibria were active during the last 1–2 Ma. Keywords: uranium isotopes, multiple-collector ICP-MS, waste management, remobilisation, migration

  16. Sterilization of Extracted Human Teeth.

    Science.gov (United States)

    Pantera, Eugene A., Jr.; Schuster, George S.

    1990-01-01

    At present, there is no specific recommendation for sterilization of extracted human teeth used in dental technique courses. The purpose of this study was to determine whether autoclaving would be effective in the sterilization of extracted teeth without compromising the characteristics that make their use in clinical simulations desirable. (MLW)

  17. Taking Care of Your Teeth

    Science.gov (United States)

    ... the most damaging (especially if you don't brush your teeth afterward) because you don't produce as much ... starches) with a meal. If you can't brush your teeth after eating, rinse your mouth with water or ...

  18. Taking Care of Your Teeth

    Science.gov (United States)

    ... the back. Have your dentist show you the best way to brush to get your teeth clean without damaging your gums. Take your time ... extra clean and can help you learn the best way to brush and floss. It's not just brushing and flossing that keep your teeth healthy — you also need to be careful about ...

  19. Real Algebraic Geometry

    CERN Document Server

    Mahé, Louis; Roy, Marie-Françoise

    1992-01-01

    Ten years after the first Rennes international meeting on real algebraic geometry, the second one looked at the developments in the subject during the intervening decade - see the 6 survey papers listed below. Further contributions from the participants on recent research covered real algebra and geometry, topology of real algebraic varieties and 16thHilbert problem, classical algebraic geometry, techniques in real algebraic geometry, algorithms in real algebraic geometry, semialgebraic geometry, real analytic geometry. CONTENTS: Survey papers: M. Knebusch: Semialgebraic topology in the last ten years.- R. Parimala: Algebraic and topological invariants of real algebraic varieties.- Polotovskii, G.M.: On the classification of decomposing plane algebraic curves.- Scheiderer, C.: Real algebra and its applications to geometry in the last ten years: some major developments and results.- Shustin, E.L.: Topology of real plane algebraic curves.- Silhol, R.: Moduli problems in real algebraic geometry. Further contribu...

  20. Triple Teeth: Report of an Unusual Case

    Directory of Open Access Journals (Sweden)

    Prashant Babaji

    2012-01-01

    Full Text Available Fusion or synodontia is a union of two or more than two developing teeth. Commonly fusion occurs between teeth of the same dentition, mixed dentition, or between normal and supernumerary teeth. Fused primary teeth present with several clinical problems like caries, periodontal problem, arch asymmetry, delayed eruption, ectopic eruption of succedaneous teeth, aesthetic, and other complications. This paper presents a rare and unusual case of triple teeth in mandibular primary dentition.

  1. Triple Teeth: Report of an Unusual Case

    OpenAIRE

    Prashant Babaji; Prasanth, M. A.; Ajith R. Gowda; Soumya Ajith; Henston D'Souza; K. P. Ashok

    2012-01-01

    Fusion or synodontia is a union of two or more than two developing teeth. Commonly fusion occurs between teeth of the same dentition, mixed dentition, or between normal and supernumerary teeth. Fused primary teeth present with several clinical problems like caries, periodontal problem, arch asymmetry, delayed eruption, ectopic eruption of succedaneous teeth, aesthetic, and other complications. This paper presents a rare and unusual case of triple teeth in mandibular primary dentition.

  2. Triple teeth: report of an unusual case.

    Science.gov (United States)

    Babaji, Prashant; Prasanth, M A; Gowda, Ajith R; Ajith, Soumya; D'Souza, Henston; Ashok, K P

    2012-01-01

    Fusion or synodontia is a union of two or more than two developing teeth. Commonly fusion occurs between teeth of the same dentition, mixed dentition, or between normal and supernumerary teeth. Fused primary teeth present with several clinical problems like caries, periodontal problem, arch asymmetry, delayed eruption, ectopic eruption of succedaneous teeth, aesthetic, and other complications. This paper presents a rare and unusual case of triple teeth in mandibular primary dentition.

  3. Geometry and its applications

    CERN Document Server

    Meyer, Walter J

    2006-01-01

    Meyer''s Geometry and Its Applications, Second Edition, combines traditional geometry with current ideas to present a modern approach that is grounded in real-world applications. It balances the deductive approach with discovery learning, and introduces axiomatic, Euclidean geometry, non-Euclidean geometry, and transformational geometry. The text integrates applications and examples throughout and includes historical notes in many chapters. The Second Edition of Geometry and Its Applications is a significant text for any college or university that focuses on geometry''s usefulness in other disciplines. It is especially appropriate for engineering and science majors, as well as future mathematics teachers.* Realistic applications integrated throughout the text, including (but not limited to): - Symmetries of artistic patterns- Physics- Robotics- Computer vision- Computer graphics- Stability of architectural structures- Molecular biology- Medicine- Pattern recognition* Historical notes included in many chapters...

  4. Supernumerary Teeth in Nepalese Children

    Directory of Open Access Journals (Sweden)

    Varun Pratap Singh

    2014-01-01

    Full Text Available Objective. The objectives of the present study were to investigate the prevalence and characteristics of supernumerary teeth in a patient sample of Nepalese children. Study Design. A survey was performed on 2684 patients (1829 females and 1035 males ranging in age from 6 to 14 for the presence of supernumerary teeth. For each patient with supernumerary teeth the demographic variables (age and sex, number, location, eruption status, and morphology were recorded. Descriptive statistics were performed. Results. Supernumerary teeth were detected in 46 subjects (1.6%, of which 26 were males and 20 were females with a male : female ratio of 1.3 : 1. The most commonly found supernumerary tooth was mesiodens followed by maxillary premolars, maxillary lateral incisor, and mandibular lateral incisor. Of the 55 supernumerary teeth examined, 58.18% (n=32 had conical morphology, followed by tuberculate (30.90%, n=17 and supplemental (10.90%, n=6 forms. The majority of the supernumerary teeth were erupted (56.36%, n=31. Conclusion. The prevalence of supernumerary teeth in Nepalese children was found to be 1.6%, the most frequent type being mesiodens. Conical morphology was found to be the most common form of supernumerary tooth.

  5. Supernumerary teeth in Nepalese children.

    Science.gov (United States)

    Singh, Varun Pratap; Sharma, Amita; Sharma, Sonam

    2014-01-01

    The objectives of the present study were to investigate the prevalence and characteristics of supernumerary teeth in a patient sample of Nepalese children. A survey was performed on 2684 patients (1829 females and 1035 males) ranging in age from 6 to 14 for the presence of supernumerary teeth. For each patient with supernumerary teeth the demographic variables (age and sex), number, location, eruption status, and morphology were recorded. Descriptive statistics were performed. Supernumerary teeth were detected in 46 subjects (1.6%), of which 26 were males and 20 were females with a male : female ratio of 1.3 : 1. The most commonly found supernumerary tooth was mesiodens followed by maxillary premolars, maxillary lateral incisor, and mandibular lateral incisor. Of the 55 supernumerary teeth examined, 58.18% (n = 32) had conical morphology, followed by tuberculate (30.90%, n = 17) and supplemental (10.90%, n = 6) forms. The majority of the supernumerary teeth were erupted (56.36%, n = 31). The prevalence of supernumerary teeth in Nepalese children was found to be 1.6%, the most frequent type being mesiodens. Conical morphology was found to be the most common form of supernumerary tooth.

  6. Affine and Projective Geometry

    CERN Document Server

    Bennett, M K

    1995-01-01

    An important new perspective on AFFINE AND PROJECTIVE GEOMETRY. This innovative book treats math majors and math education students to a fresh look at affine and projective geometry from algebraic, synthetic, and lattice theoretic points of view. Affine and Projective Geometry comes complete with ninety illustrations, and numerous examples and exercises, covering material for two semesters of upper-level undergraduate mathematics. The first part of the book deals with the correlation between synthetic geometry and linear algebra. In the second part, geometry is used to introduce lattice theory

  7. Introduction to projective geometry

    CERN Document Server

    Wylie, C R

    2008-01-01

    This lucid introductory text offers both an analytic and an axiomatic approach to plane projective geometry. The analytic treatment builds and expands upon students' familiarity with elementary plane analytic geometry and provides a well-motivated approach to projective geometry. Subsequent chapters explore Euclidean and non-Euclidean geometry as specializations of the projective plane, revealing the existence of an infinite number of geometries, each Euclidean in nature but characterized by a different set of distance- and angle-measurement formulas. Outstanding pedagogical features include w

  8. Geometry essentials for dummies

    CERN Document Server

    Ryan, Mark

    2011-01-01

    Just the critical concepts you need to score high in geometry This practical, friendly guide focuses on critical concepts taught in a typical geometry course, from the properties of triangles, parallelograms, circles, and cylinders, to the skills and strategies you need to write geometry proofs. Geometry Essentials For Dummies is perfect for cramming or doing homework, or as a reference for parents helping kids study for exams. Get down to the basics - get a handle on the basics of geometry, from lines, segments, and angles, to vertices, altitudes, and diagonals Conque

  9. Restoring primary anterior teeth.

    Science.gov (United States)

    Waggoner, William F

    2002-01-01

    A variety of esthetic restorative materials are available for restoring primary incisors. Knowledge of the specific strengths, weakness, and properties of each material will enhance the clinician's ability to make the best choice of selection for each individual situation. Intracoronal restorations of primary teeth may utilize resin composites, glass ionomer cements, resin-modified ionomers, or polyacid-modified resins. Each has distinct advantages and disadvantages and the clinical conditions of placement may be a strong determining factor as to which material is utilized. Full coronal restoration of primary incisors may be indicated for a number of reasons. Crowns available for restoration of primary incisors include those that are directly bonded onto the tooth, which generally are a resin material, and those crowns that are luted onto the tooth and are some type of stainless steel crown. However, due to lack of supporting clinical data, none of the crowns can be said to be superior to the others under all circumstances. Though caries in the mandibular region is rare, restorative solutions for mandibular incisors are needed. Neither stainless steel crowns nor celluloid crown forms are made specifically for mandibular incisors. Many options exist to repair carious primary incisors, but there is insufficient controlled, clinical data to suggest that one type of restoration is superior to another. This does not discount the fact that dentists have been using many of these crowns for years with much success. Operator preferences, esthetic demands by parents, the child's behavior, and moisture and hemorrhage control are all variables which affect the decision and ultimate outcome of whatever restorative treatment is chosen.

  10. Take Care of Your Child's Teeth

    Science.gov (United States)

    ... Sections The Basics Overview Tooth Decay Take Action! Brushing Tips Use Fluoride Fluoride Supplements Foods and Drinks Dental Checkups The Basics The Basics: Overview Your child’s first teeth, or baby teeth, are important. Baby teeth hold space for adult teeth. Taking ...

  11. Multiple supernumerary teeth in the mixed dentition.

    Science.gov (United States)

    Nadkarni, U M; Muthu, M S; Damle, S G; Sujan, S G; Kakade, A

    1999-03-01

    Supernumerary or extra teeth result from disturbances during the initiation and proliferation stages of dental development. Teeth formed in excess of the normal number are termed supernumerary teeth. A supernumerary tooth may closely resemble the teeth of the group to which it belongs i.e. molars, premolars or anterior teeth or it may bear little resemblance in size or shape to the teeth with which it is associated. Discussed here are reports of three cases with multiple supernumerary teeth in the mixed dentition and its management.

  12. The Geometry Conference

    CERN Document Server

    Bárány, Imre; Vilcu, Costin

    2016-01-01

    This volume presents easy-to-understand yet surprising properties obtained using topological, geometric and graph theoretic tools in the areas covered by the Geometry Conference that took place in Mulhouse, France from September 7–11, 2014 in honour of Tudor Zamfirescu on the occasion of his 70th anniversary. The contributions address subjects in convexity and discrete geometry, in distance geometry or with geometrical flavor in combinatorics, graph theory or non-linear analysis. Written by top experts, these papers highlight the close connections between these fields, as well as ties to other domains of geometry and their reciprocal influence. They offer an overview on recent developments in geometry and its border with discrete mathematics, and provide answers to several open questions. The volume addresses a large audience in mathematics, including researchers and graduate students interested in geometry and geometrical problems.

  13. Supernumerary teeth in non-syndromic patients

    OpenAIRE

    Mali, Santosh; Karjodkar, Freny Rashmiraj; Sontakke, Subodh; Sansare, Kaustubh

    2012-01-01

    Hyperdontia or supernumerary teeth without associated syndrome is a rare phenomenon, as supernumerary teeth are usually associated with cleft lip and palate or other syndromes such as Gardner's syndrome, cleidocranial dysplasia, and so on. Five patients with supernumerary teeth visited our department. They had no familial history or other pathology, certain treatment protocols was modified due to the presence of supernumerary teeth. Non-syndromic supernumerary teeth, if asymptomatic, need to ...

  14. Methods of Geometry

    CERN Document Server

    Smith, James T

    2000-01-01

    A practical, accessible introduction to advanced geometry Exceptionally well-written and filled with historical and bibliographic notes, Methods of Geometry presents a practical and proof-oriented approach. The author develops a wide range of subject areas at an intermediate level and explains how theories that underlie many fields of advanced mathematics ultimately lead to applications in science and engineering. Foundations, basic Euclidean geometry, and transformations are discussed in detail and applied to study advanced plane geometry, polyhedra, isometries, similarities, and symmetry. An

  15. Revolutions of Geometry

    CERN Document Server

    O'Leary, Michael

    2010-01-01

    Guides readers through the development of geometry and basic proof writing using a historical approach to the topic. In an effort to fully appreciate the logic and structure of geometric proofs, Revolutions of Geometry places proofs into the context of geometry's history, helping readers to understand that proof writing is crucial to the job of a mathematician. Written for students and educators of mathematics alike, the book guides readers through the rich history and influential works, from ancient times to the present, behind the development of geometry. As a result, readers are successfull

  16. Euclidean geometry and transformations

    CERN Document Server

    Dodge, Clayton W

    1972-01-01

    This introduction to Euclidean geometry emphasizes transformations, particularly isometries and similarities. Suitable for undergraduate courses, it includes numerous examples, many with detailed answers. 1972 edition.

  17. Fundamental concepts of geometry

    CERN Document Server

    Meserve, Bruce E

    1983-01-01

    Demonstrates relationships between different types of geometry. Provides excellent overview of the foundations and historical evolution of geometrical concepts. Exercises (no solutions). Includes 98 illustrations.

  18. Restoration of endodontically treated teeth.

    Science.gov (United States)

    Mannocci, F; Cowie, J

    2014-03-01

    The restoration of endodontically treated teeth has undergone significant changes in the last 20 years. Most of these changes are associated with the preservation of tooth structure, this has been achieved first of all with the increasing use of operative microscopes, nickel titanium instruments and more recently cone beam computed tomography; these instruments have allowed the clinicians to reduce significantly the amount of coronal and radicular hard tooth tissue removed in the process of cutting access cavities. The use of composites has also allowed the clinicians to restore with adhesive techniques teeth that would otherwise require extensive and destructive mechanical retentions. The use of partial crowns is becoming increasingly popular and this also helps prevent tooth structure loss. This article will focus on the choices available to restore both anterior and posterior teeth and will focus more on these contemporary adhesive techniques.

  19. Impacted Teeth: An Interdisciplinary Perspective.

    Science.gov (United States)

    Kaczor-Urbanowicz, Karolina; Zadurska, Małgorzata; Czochrowska, Ewa

    2016-01-01

    A tooth normally erupts when half to three-quarters of its final root length has developed. Tooth impaction is usually diagnosed well after this period and is generally asymptomatic. It is principally for this reason that patients seek treatment later than optimal. Tooth impaction is a common problem in daily orthodontic practice and, in most cases, it is recognized by chance in a routine dental examination. Therefore, it is very important that dental practitioners are aware of this condition, since early detection and intervention may help to prevent many harmful complications. The treatment of impacted teeth requires multidisciplinary cooperation between orthodontists, oral surgeons and sometimes periodontists. Orthodontic treatment and surgical exposure of impacted teeth are performed in order to bring the impacted tooth into the line of the arch. The treatment is long, more complicated and challenging. This article presents an overview of the prevalence, etiology, diagnosis, treatment and complications associated with the management of impacted teeth.

  20. Tips for splinting traumatised teeth

    LENUS (Irish Health Repository)

    Leith, Rona

    2017-11-01

    A splint is required when teeth are mobile or need to be repositioned following a traumatic injury. The aim of splinting is to stabilise the injured tooth and maintain its position throughout the splinting period, improve function and provide comfort. Current best practice guidelines from the International Association for Dental Traumatology (IADT) recommend splinting for luxated, avulsed, root fractured and traumatically loosened permanent teeth.1,2 Splinting of primary teeth is usually not feasible. In general, the prognosis of a traumatised tooth is determined by the type of injury rather than the type of splint.3 However, correct splinting is important to maximise healing of the soft and hard tissues, and prevent further injury.1

  1. Tips for splinting traumatised teeth

    LENUS (Irish Health Repository)

    Leith, Rona

    2017-10-01

    A splint is required when teeth are mobile or need to be repositioned following a traumatic injury. The aim of splinting is to stabilise the injured tooth and maintain its position throughout the splinting period, improve function and provide comfort. Current best practice guidelines from the International Association for Dental Traumatology (IADT) recommend splinting for luxated, avulsed, root fractured and traumatically loosened permanent teeth.1,2 Splinting of primary teeth is usually not feasible. In general, the prognosis of a traumatised tooth is determined by the type of injury rather than the type of splint.3 However, correct splinting is important to maximise healing of the soft and hard tissues, and prevent further injury.1-6

  2. Bayes reconstruction of missing teeth

    DEFF Research Database (Denmark)

    Sporring, Jon; Jensen, Katrine Hommelhoff

    2008-01-01

     We propose a method for restoring the surface of tooth crowns in a 3D model of a human denture, so that the pose and anatomical features of the tooth will work well for chewing. This is achieved by including information about the position and anatomy of the other teeth in the mouth. Our system...... contains two major parts: A statistical model of a selection of tooth shapes and a reconstruction of missing data. We use a training set consisting of 3D scans of dental cast models obtained with a laser scanner, and we have build a model of the shape variability of the teeth, their neighbors...... regularization of the log-likelihood estimate based on differential geometrical properties of teeth surfaces, and we show general conditions under which this may be considered a Bayes prior.Finally we use Bayes method to propose the reconstruction of missing data, for e.g. finding the most probable shape...

  3. Geometry Professionalized for Teachers.

    Science.gov (United States)

    Christofferson, Halbert Carl

    Written in 1933, this book grew out of the author's concern that college matehmatics sequences of the day, although appropriate in algebra preparation, did not adequately prepare teachers of geometry. This book describes a course intended to remedy this by providing for both a comprehensive study of geometry as an axiomatically defined structure…

  4. Foundations of algebraic geometry

    CERN Document Server

    Weil, A

    1946-01-01

    This classic is one of the cornerstones of modern algebraic geometry. At the same time, it is entirely self-contained, assuming no knowledge whatsoever of algebraic geometry, and no knowledge of modern algebra beyond the simplest facts about abstract fields and their extensions, and the bare rudiments of the theory of ideals.

  5. Geometry + Technology = Proof

    Science.gov (United States)

    Lyublinskaya, Irina; Funsch, Dan

    2012-01-01

    Several interactive geometry software packages are available today to secondary school teachers. An example is The Geometer's Sketchpad[R] (GSP), also known as Dynamic Geometry[R] software, developed by Key Curriculum Press. This numeric based technology has been widely adopted in the last twenty years, and a vast amount of creativity has been…

  6. Designs and finite geometries

    CERN Document Server

    1996-01-01

    Designs and Finite Geometries brings together in one place important contributions and up-to-date research results in this important area of mathematics. Designs and Finite Geometries serves as an excellent reference, providing insight into some of the most important research issues in the field.

  7. Supersymmetric Sigma Model Geometry

    Directory of Open Access Journals (Sweden)

    Ulf Lindström

    2012-08-01

    Full Text Available This is a review of how sigma models formulated in Superspace have become important tools for understanding geometry. Topics included are: The (hyperkähler reduction; projective superspace; the generalized Legendre construction; generalized Kähler geometry and constructions of hyperkähler metrics on Hermitian symmetric spaces.

  8. A Lorentzian quantum geometry

    Energy Technology Data Exchange (ETDEWEB)

    Grotz, Andreas

    2011-10-07

    In this thesis, a formulation of a Lorentzian quantum geometry based on the framework of causal fermion systems is proposed. After giving the general definition of causal fermion systems, we deduce space-time as a topological space with an underlying causal structure. Restricting attention to systems of spin dimension two, we derive the objects of our quantum geometry: the spin space, the tangent space endowed with a Lorentzian metric, connection and curvature. In order to get the correspondence to classical differential geometry, we construct examples of causal fermion systems by regularizing Dirac sea configurations in Minkowski space and on a globally hyperbolic Lorentzian manifold. When removing the regularization, the objects of our quantum geometry reduce to the common objects of spin geometry on Lorentzian manifolds, up to higher order curvature corrections.

  9. Endodontic management of taurodontic teeth

    Directory of Open Access Journals (Sweden)

    Prakash R

    2005-01-01

    Full Text Available Taurodontism is a morpho-anatomical change in the shape of the tooth in which the body of the tooth is enlarged and the roots are reduced in size. Although taurodontism is a dental rarity, this unusual radicular form should merit circumspect considerations in planning and treatment. Endodontic management in taurodont teeth has been described as complex and difficult. The present paper describes the successful completion of endodontic treatment in three taurodontic teeth with appropriate use of instruments and techniques and also emphasizes the need for post endodontic rehabilitation.

  10. MATHEMATICAL MODEL OF FORM MACHINING OF THE CONVEXO-CONCAVE NOVIKOV GEAR TEETH

    Directory of Open Access Journals (Sweden)

    Tadeusz MARKOWSKI

    2016-03-01

    Full Text Available Article presents mathematical model of form machining of cylindrical convexo-concave Novikov gear teeth by means of disk-type tools. Example of these king of tools is disk-type milling cutter or grinding wheel. Moreover based on the given convex and concave tooth geometry the tool profile has been established.

  11. The pulpectomy in primary teeth.

    Science.gov (United States)

    Nedley, Michael P

    2002-08-01

    The pulpectomy is an underutilized treatment modality for severely infected primary teeth. The author presents two pulpectomy cases that were filled with Vitapex. Vitapex is an excellent filling material for primary tooth pulpectomies. Its clinical characteristics and ease of use may make the pulpectomy procedure a more-attractive alternative to extraction.

  12. Non-Euclidean geometry

    CERN Document Server

    Kulczycki, Stefan

    2008-01-01

    This accessible approach features two varieties of proofs: stereometric and planimetric, as well as elementary proofs that employ only the simplest properties of the plane. A short history of geometry precedes a systematic exposition of the principles of non-Euclidean geometry.Starting with fundamental assumptions, the author examines the theorems of Hjelmslev, mapping a plane into a circle, the angle of parallelism and area of a polygon, regular polygons, straight lines and planes in space, and the horosphere. Further development of the theory covers hyperbolic functions, the geometry of suff

  13. Complex and symplectic geometry

    CERN Document Server

    Medori, Costantino; Tomassini, Adriano

    2017-01-01

    This book arises from the INdAM Meeting "Complex and Symplectic Geometry", which was held in Cortona in June 2016. Several leading specialists, including young researchers, in the field of complex and symplectic geometry, present the state of the art of their research on topics such as the cohomology of complex manifolds; analytic techniques in Kähler and non-Kähler geometry; almost-complex and symplectic structures; special structures on complex manifolds; and deformations of complex objects. The work is intended for researchers in these areas.

  14. Students' perceptions of pre-clinical endodontic training with artificial teeth compared to extracted human teeth.

    Science.gov (United States)

    Al-Sudani, D I; Basudan, S O

    2017-11-01

    Artificial teeth have several advantages in pre-clinical endodontics training. This study aimed to compare artificial resin teeth with extracted human teeth, from a student's perspective, during a pre-clinical undergraduate endodontic course for three consecutive academic years (2011-2014). At the end of the course, students completed a questionnaire that included questions about their perceptions of the difficulty of artificial teeth vs. natural teeth and ranked the perceived advantages of artificial teeth. Participants expressed that all procedures, except obturation, were more difficult to perform on artificial teeth than on natural teeth, a result that was due to the hardness of the resin. They ranked the fairness and availability as the best advantages. Artificial teeth have multiple advantages but cannot replace natural teeth. The physical characteristics through the manufacturing material of artificial teeth should be enhanced to increase wider use and acceptance. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Aetiology of supernumerary teeth: a literature review.

    Science.gov (United States)

    Anthonappa, R P; King, N M; Rabie, A B M

    2013-10-01

    Supernumerary teeth are teeth, or tooth-like structures that have either erupted or remain unerupted in addition to the 20 primary and 32 permanent teeth. This paper attempts to (a) provide an overview of the proposed hypotheses and the current understanding of the aetiology of supernumerary teeth, and (b) review the published cases of supernumerary teeth occurring in families. No studies have been able to distinguish between different aetiologies for the different locations of supernumerary teeth, while, from a developmental or molecular perspective, the proposed hypotheses may be plausible and explains the origin of different types of supernumerary teeth. The only clearly evident feature, based on the existing published reports, is that it is logical to state that supernumerary teeth have a genetic component in their aetiology.

  16. Geometry without topology as a new conception of geometry

    Directory of Open Access Journals (Sweden)

    Yuri A. Rylov

    2002-01-01

    geometry. In T-geometry, any space region is isometrically embeddable in the space, whereas in Riemannian geometry only convex region is isometrically embeddable. T-geometric conception appears to be more consistent logically, than the Riemannian one.

  17. Complex algebraic geometry

    CERN Document Server

    Kollár, János

    1997-01-01

    This volume contains the lectures presented at the third Regional Geometry Institute at Park City in 1993. The lectures provide an introduction to the subject, complex algebraic geometry, making the book suitable as a text for second- and third-year graduate students. The book deals with topics in algebraic geometry where one can reach the level of current research while starting with the basics. Topics covered include the theory of surfaces from the viewpoint of recent higher-dimensional developments, providing an excellent introduction to more advanced topics such as the minimal model program. Also included is an introduction to Hodge theory and intersection homology based on the simple topological ideas of Lefschetz and an overview of the recent interactions between algebraic geometry and theoretical physics, which involve mirror symmetry and string theory.

  18. Invitation to geometry

    CERN Document Server

    Melzak, Z A

    2008-01-01

    Intended for students of many different backgrounds with only a modest knowledge of mathematics, this text features self-contained chapters that can be adapted to several types of geometry courses. 1983 edition.

  19. Lectures on Symplectic Geometry

    CERN Document Server

    Silva, Ana Cannas

    2001-01-01

    The goal of these notes is to provide a fast introduction to symplectic geometry for graduate students with some knowledge of differential geometry, de Rham theory and classical Lie groups. This text addresses symplectomorphisms, local forms, contact manifolds, compatible almost complex structures, Kaehler manifolds, hamiltonian mechanics, moment maps, symplectic reduction and symplectic toric manifolds. It contains guided problems, called homework, designed to complement the exposition or extend the reader's understanding. There are by now excellent references on symplectic geometry, a subset of which is in the bibliography of this book. However, the most efficient introduction to a subject is often a short elementary treatment, and these notes attempt to serve that purpose. This text provides a taste of areas of current research and will prepare the reader to explore recent papers and extensive books on symplectic geometry where the pace is much faster. For this reprint numerous corrections and cl...

  20. Introduction to tropical geometry

    CERN Document Server

    Maclagan, Diane

    2015-01-01

    Tropical geometry is a combinatorial shadow of algebraic geometry, offering new polyhedral tools to compute invariants of algebraic varieties. It is based on tropical algebra, where the sum of two numbers is their minimum and the product is their sum. This turns polynomials into piecewise-linear functions, and their zero sets into polyhedral complexes. These tropical varieties retain a surprising amount of information about their classical counterparts. Tropical geometry is a young subject that has undergone a rapid development since the beginning of the 21st century. While establishing itself as an area in its own right, deep connections have been made to many branches of pure and applied mathematics. This book offers a self-contained introduction to tropical geometry, suitable as a course text for beginning graduate students. Proofs are provided for the main results, such as the Fundamental Theorem and the Structure Theorem. Numerous examples and explicit computations illustrate the main concepts. Each of t...

  1. Geometry of differential equations

    CERN Document Server

    Khovanskiĭ, A; Vassiliev, V

    1998-01-01

    This volume contains articles written by V. I. Arnold's colleagues on the occasion of his 60th birthday. The articles are mostly devoted to various aspects of geometry of differential equations and relations to global analysis and Hamiltonian mechanics.

  2. Geometry-controlled kinetics.

    Science.gov (United States)

    Bénichou, O; Chevalier, C; Klafter, J; Meyer, B; Voituriez, R

    2010-06-01

    It has long been appreciated that the transport properties of molecules can control reaction kinetics. This effect can be characterized by the time it takes a diffusing molecule to reach a target-the first-passage time (FPT). Determining the FPT distribution in realistic confined geometries has until now, however, seemed intractable. Here, we calculate this FPT distribution analytically and show that transport processes as varied as regular diffusion, anomalous diffusion, and diffusion in disordered media and fractals, fall into the same universality classes. Beyond the theoretical aspect, this result changes our views on standard reaction kinetics and we introduce the concept of 'geometry-controlled kinetics'. More precisely, we argue that geometry-and in particular the initial distance between reactants in 'compact' systems-can become a key parameter. These findings could help explain the crucial role that the spatial organization of genes has in transcription kinetics, and more generally the impact of geometry on diffusion-limited reactions.

  3. The geometry of geodesics

    CERN Document Server

    Busemann, Herbert

    2005-01-01

    A comprehensive approach to qualitative problems in intrinsic differential geometry, this text examines Desarguesian spaces, perpendiculars and parallels, covering spaces, the influence of the sign of the curvature on geodesics, more. 1955 edition. Includes 66 figures.

  4. Geometry and Combinatorics

    DEFF Research Database (Denmark)

    Kokkendorff, Simon Lyngby

    2002-01-01

    The subject of this Ph.D.-thesis is somewhere in between continuous and discrete geometry. Chapter 2 treats the geometry of finite point sets in semi-Riemannian hyperquadrics,using a matrix whose entries are a trigonometric function of relative distances in a given point set. The distance...... to the geometry of a simplex in a semi-Riemannian hyperquadric. In chapter 3 we study which finite metric spaces that are realizable in a hyperbolic space in the limit where curvature goes to -∞. We show that such spaces are the so called leaf spaces, the set of degree 1 vertices of weighted trees. We also...... establish results on the limiting geometry of such an isometrically realized leaf space simplex in hyperbolic space, when curvature goes to -∞. Chapter 4 discusses negative type of metric spaces. We give a measure theoretic treatment of this concept and related invariants. The theory developed...

  5. Elementary differential geometry

    CERN Document Server

    Pressley, Andrew

    2001-01-01

    Curves and surfaces are objects that everyone can see, and many of the questions that can be asked about them are natural and easily understood Differential geometry is concerned with the precise mathematical formulation of some of these questions, and with trying to answer them using calculus techniques It is a subject that contains some of the most beautiful and profound results in mathematics yet many of these are accessible to higher-level undergraduates Elementary Differential Geometry presents the main results in the differential geometry of curves and surfaces while keeping the prerequisites to an absolute minimum Nothing more than first courses in linear algebra and multivariate calculus are required, and the most direct and straightforward approach is used at all times Numerous diagrams illustrate both the ideas in the text and the examples of curves and surfaces discussed there The book will provide an invaluable resource to all those taking a first course in differential geometry, for their lecture...

  6. d-geometries revisited

    CERN Document Server

    Ceresole, Anna; Gnecchi, Alessandra; Marrani, Alessio

    2013-01-01

    We analyze some properties of the four dimensional supergravity theories which originate from five dimensions upon reduction. They generalize to N>2 extended supersymmetries the d-geometries with cubic prepotentials, familiar from N=2 special K\\"ahler geometry. We emphasize the role of a suitable parametrization of the scalar fields and the corresponding triangular symplectic basis. We also consider applications to the first order flow equations for non-BPS extremal black holes.

  7. Intermediate algebra & analytic geometry

    CERN Document Server

    Gondin, William R

    1967-01-01

    Intermediate Algebra & Analytic Geometry Made Simple focuses on the principles, processes, calculations, and methodologies involved in intermediate algebra and analytic geometry. The publication first offers information on linear equations in two unknowns and variables, functions, and graphs. Discussions focus on graphic interpretations, explicit and implicit functions, first quadrant graphs, variables and functions, determinate and indeterminate systems, independent and dependent equations, and defective and redundant systems. The text then examines quadratic equations in one variable, system

  8. "Early baby teeth": Folklore and facts.

    Science.gov (United States)

    Maheswari, N Uma; Kumar, B P; Karunakaran; Kumaran, S Thanga

    2012-08-01

    Variations in the newborns' oral cavity have been an enduring interest to the pediatric dentist. The occurrence of natal and neonatal teeth is a rare anomaly, which for centuries has been associated with diverse superstitions among many different ethnic groups. Natal teeth are more frequent than neonatal teeth, the ratio being approximately 3:1. The purpose of this case report is to review the literature related to the natal teeth folklore and misconceptions and discuss their possible etiology and treatment.

  9. Coevolutionary patterning of teeth and taste buds

    OpenAIRE

    Bloomquist, R.F.; Parnell, N; Phillips, K A; Fowler, T E; Yu, Tian; Sharpe, Paul T.; Streelman, J T

    2015-01-01

    Teeth and taste buds are iteratively patterned structures that line the oro-pharynx of vertebrates. Biologists do not fully understand how teeth and taste buds develop from undifferentiated epithelium or how variation in organ density is regulated. These organs are typically studied independently because of their separate anatomical location in mammals: teeth on the jaw margin and taste buds on the tongue. However, in many aquatic animals like bony fishes, teeth and taste buds are colocalized...

  10. SOC and Fractal Geometry

    Science.gov (United States)

    McAteer, R. T. J.

    2013-06-01

    When Mandelbrot, the father of modern fractal geometry, made this seemingly obvious statement he was trying to show that we should move out of our comfortable Euclidean space and adopt a fractal approach to geometry. The concepts and mathematical tools of fractal geometry provides insight into natural physical systems that Euclidean tools cannot do. The benet from applying fractal geometry to studies of Self-Organized Criticality (SOC) are even greater. SOC and fractal geometry share concepts of dynamic n-body interactions, apparent non-predictability, self-similarity, and an approach to global statistics in space and time that make these two areas into naturally paired research techniques. Further, the iterative generation techniques used in both SOC models and in fractals mean they share common features and common problems. This chapter explores the strong historical connections between fractal geometry and SOC from both a mathematical and conceptual understanding, explores modern day interactions between these two topics, and discusses how this is likely to evolve into an even stronger link in the near future.

  11. Multiple Unerupted Permanent Teeth Associated with Noonan ...

    African Journals Online (AJOL)

    the atypical dental anomalies such as multiple unerupted permanent teeth; multiple submerged and retained deciduous teeth and supernumerary teeth associated with other known clinical features in a child with NS. Case Report. A 13-year-old boy reported to the Department of Pediatric. Dentistry with the chief complaint of ...

  12. Delayed replantation of avulsed teeth

    Directory of Open Access Journals (Sweden)

    Adil N

    2007-05-01

    Full Text Available Dental injuries are very common and their extent has been classified by Ellis. Avulsion of tooth is a grievous injury and ranges from 1-16% among the traumatic injuries, of which maxillary anterior are commonest. Reimplantation of avulsed teeth is a standard procedure. However, it has certain limitations. Most often their management is very challenging. In this case report we are presenting the management of maxillary incisors by replantation after 36 hrs in a 12 year old girl.

  13. Sources of hyperbolic geometry

    CERN Document Server

    Stillwell, John

    1996-01-01

    This book presents, for the first time in English, the papers of Beltrami, Klein, and Poincaré that brought hyperbolic geometry into the mainstream of mathematics. A recognition of Beltrami comparable to that given the pioneering works of Bolyai and Lobachevsky seems long overdue-not only because Beltrami rescued hyperbolic geometry from oblivion by proving it to be logically consistent, but because he gave it a concrete meaning (a model) that made hyperbolic geometry part of ordinary mathematics. The models subsequently discovered by Klein and Poincaré brought hyperbolic geometry even further down to earth and paved the way for the current explosion of activity in low-dimensional geometry and topology. By placing the works of these three mathematicians side by side and providing commentaries, this book gives the student, historian, or professional geometer a bird's-eye view of one of the great episodes in mathematics. The unified setting and historical context reveal the insights of Beltrami, Klein, and Po...

  14. Students Discovering Spherical Geometry Using Dynamic Geometry Software

    Science.gov (United States)

    Guven, Bulent; Karatas, Ilhan

    2009-01-01

    Dynamic geometry software (DGS) such as Cabri and Geometers' Sketchpad has been regularly used worldwide for teaching and learning Euclidean geometry for a long time. The DGS with its inductive nature allows students to learn Euclidean geometry via explorations. However, with respect to non-Euclidean geometries, do we need to introduce them to…

  15. [Supernumerary teeth located in molar region: three cases report].

    Science.gov (United States)

    Dai, Jie; Yang, Weijiang; Shen, Xuanjiang

    2011-08-01

    Supernumerary teeth is one of the teeth dysplasia that the number of teeth exceeded normal. Most of supernumerary teeth reported were located in anterior teeth region, but rare cases were reported in molar region. This paper reported three cases that supernumerary teeth located in molar region.

  16. Natal and neonatal teeth: Literature review and report of seven ...

    African Journals Online (AJOL)

    Teeth that are present in newborn infants are called "natal teeth" while teeth that erupt within the first 4 weeks after birth are called "neonatal teeth". The incidence of the appearance of natal and neonatal teeth has been reported to be between one in every 1000 and one in every 6000 births. Natal teeth may be ...

  17. Geometry of hypersurfaces

    CERN Document Server

    Cecil, Thomas E

    2015-01-01

    This exposition provides the state-of-the art on the differential geometry of hypersurfaces in real, complex, and quaternionic space forms. Special emphasis is placed on isoparametric and Dupin hypersurfaces in real space forms as well as Hopf hypersurfaces in complex space forms. The book is accessible to a reader who has completed a one-year graduate course in differential geometry. The text, including open problems and an extensive list of references, is an excellent resource for researchers in this area. Geometry of Hypersurfaces begins with the basic theory of submanifolds in real space forms. Topics include shape operators, principal curvatures and foliations, tubes and parallel hypersurfaces, curvature spheres and focal submanifolds. The focus then turns to the theory of isoparametric hypersurfaces in spheres. Important examples and classification results are given, including the construction of isoparametric hypersurfaces based on representations of Clifford algebras. An in-depth treatment of Dupin hy...

  18. Complex differential geometry

    CERN Document Server

    Zheng, Fangyang

    2002-01-01

    The theory of complex manifolds overlaps with several branches of mathematics, including differential geometry, algebraic geometry, several complex variables, global analysis, topology, algebraic number theory, and mathematical physics. Complex manifolds provide a rich class of geometric objects, for example the (common) zero locus of any generic set of complex polynomials is always a complex manifold. Yet complex manifolds behave differently than generic smooth manifolds; they are more coherent and fragile. The rich yet restrictive character of complex manifolds makes them a special and interesting object of study. This book is a self-contained graduate textbook that discusses the differential geometric aspects of complex manifolds. The first part contains standard materials from general topology, differentiable manifolds, and basic Riemannian geometry. The second part discusses complex manifolds and analytic varieties, sheaves and holomorphic vector bundles, and gives a brief account of the surface classifi...

  19. Lectures on discrete geometry

    CERN Document Server

    2002-01-01

    Discrete geometry investigates combinatorial properties of configurations of geometric objects. To a working mathematician or computer scientist, it offers sophisticated results and techniques of great diversity and it is a foundation for fields such as computational geometry or combinatorial optimization. This book is primarily a textbook introduction to various areas of discrete geometry. In each area, it explains several key results and methods, in an accessible and concrete manner. It also contains more advanced material in separate sections and thus it can serve as a collection of surveys in several narrower subfields. The main topics include: basics on convex sets, convex polytopes, and hyperplane arrangements; combinatorial complexity of geometric configurations; intersection patterns and transversals of convex sets; geometric Ramsey-type results; polyhedral combinatorics and high-dimensional convexity; and lastly, embeddings of finite metric spaces into normed spaces. Jiri Matousek is Professor of Com...

  20. Geometry and Cloaking Devices

    Science.gov (United States)

    Ochiai, T.; Nacher, J. C.

    2011-09-01

    Recently, the application of geometry and conformal mappings to artificial materials (metamaterials) has attracted the attention in various research communities. These materials, characterized by a unique man-made structure, have unusual optical properties, which materials found in nature do not exhibit. By applying the geometry and conformal mappings theory to metamaterial science, it may be possible to realize so-called "Harry Potter cloaking device". Although such a device is still in the science fiction realm, several works have shown that by using such metamaterials it may be possible to control the direction of the electromagnetic field at will. We could then make an object hidden inside of a cloaking device. Here, we will explain how to design invisibility device using differential geometry and conformal mappings.

  1. Geometry and symmetry

    CERN Document Server

    Yale, Paul B

    2012-01-01

    This book is an introduction to the geometry of Euclidean, affine, and projective spaces with special emphasis on the important groups of symmetries of these spaces. The two major objectives of the text are to introduce the main ideas of affine and projective spaces and to develop facility in handling transformations and groups of transformations. Since there are many good texts on affine and projective planes, the author has concentrated on the n-dimensional cases.Designed to be used in advanced undergraduate mathematics or physics courses, the book focuses on ""practical geometry,"" emphasi

  2. Non-Riemannian geometry

    CERN Document Server

    Eisenhart, L P

    1927-01-01

    The use of the differential geometry of a Riemannian space in the mathematical formulation of physical theories led to important developments in the geometry of such spaces. The concept of parallelism of vectors, as introduced by Levi-Civita, gave rise to a theory of the affine properties of a Riemannian space. Covariant differentiation, as developed by Christoffel and Ricci, is a fundamental process in this theory. Various writers, notably Eddington, Einstein and Weyl, in their efforts to formulate a combined theory of gravitation and electromagnetism, proposed a simultaneous generalization o

  3. Geometry in everyday life

    OpenAIRE

    Graumann, Günter; Blum, Werner

    1989-01-01

    My conception of "practice-oriented-mathematical-education", which must be seen as one point of view side-by-side with others, has the aim to qualify pupils to master life and is based on a method of working on problems which are true to life. Therefore I plead for geometry teaching, where the formation of sound geometric concepts and the relevance of applications of geometry in everyday life is important. After discussing this conception a schedule of activities of everyday life where geomet...

  4. Geometry of manifolds

    CERN Document Server

    Bishop, Richard L

    2001-01-01

    First published in 1964, this book served as a text on differential geometry to several generations of graduate students all over the world. The first half of the book (Chapters 1-6) presents basics of the theory of manifolds, vector bundles, differential forms, and Lie groups, with a special emphasis on the theory of linear and affine connections. The second half of the book (Chapters 7-11) is devoted to Riemannian geometry. Following the definition and main properties of Riemannian manifolds, the authors discuss the theory of geodesics, complete Riemannian manifolds, and curvature. Next, the

  5. Teething

    Science.gov (United States)

    ... if your baby is eating solids). Use a bottle, if it seems to help, but only fill it with water. Formula, milk, or juice can all cause tooth decay. You can buy the following medicines and remedies ...

  6. Implosions and hypertoric geometry

    DEFF Research Database (Denmark)

    Dancer, A.; Kirwan, F.; Swann, A.

    2013-01-01

    The geometry of the universal hyperkahler implosion for SU (n) is explored. In particular, we show that the universal hyperkahler implosion naturally contains a hypertoric variety described in terms of quivers. Furthermore, we discuss a gauge theoretic approach to hyperkahler implosion....

  7. Foundations of Basic Geometry

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 7. Foundations of Basic Geometry. Jasbir S Chahal. General Article Volume 11 Issue 7 July 2006 pp 30-41. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/011/07/0030-0041. Keywords. Area ...

  8. Non-euclidean geometry

    CERN Document Server

    Coxeter, HSM

    1965-01-01

    This textbook introduces non-Euclidean geometry, and the third edition adds a new chapter, including a description of the two families of 'mid-lines' between two given lines and an elementary derivation of the basic formulae of spherical trigonometry and hyperbolic trigonometry, and other new material.

  9. Diophantine geometry an introduction

    CERN Document Server

    Hindry, Marc

    2000-01-01

    This is an introduction to diophantine geometry at the advanced graduate level. The book contains a proof of the Mordell conjecture which will make it quite attractive to graduate students and professional mathematicians. In each part of the book, the reader will find numerous exercises.

  10. Towards relativistic quantum geometry

    Directory of Open Access Journals (Sweden)

    Luis Santiago Ridao

    2015-12-01

    Full Text Available We obtain a gauge-invariant relativistic quantum geometry by using a Weylian-like manifold with a geometric scalar field which provides a gauge-invariant relativistic quantum theory in which the algebra of the Weylian-like field depends on observers. An example for a Reissner–Nordström black-hole is studied.

  11. Calculus and Geometry

    Indian Academy of Sciences (India)

    IAS Admin

    face area and perimeter of various shapes like sphere, cone, cylinder and circle. But an equally important geo- metric object `torus' { a shape like a scooter tube or a doughnut { is not discussed in school geometry. This is perhaps due to the non availability of this shape at the time when Archimedes (287 BC{212 BC) was ...

  12. Geometry Euclid and beyond

    CERN Document Server

    Hartshorne, Robin

    2000-01-01

    In recent years, I have been teaching a junior-senior-level course on the classi­ cal geometries. This book has grown out of that teaching experience. I assume only high-school geometry and some abstract algebra. The course begins in Chapter 1 with a critical examination of Euclid's Elements. Students are expected to read concurrently Books I-IV of Euclid's text, which must be obtained sepa­ rately. The remainder of the book is an exploration of questions that arise natu­ rally from this reading, together with their modern answers. To shore up the foundations we use Hilbert's axioms. The Cartesian plane over a field provides an analytic model of the theory, and conversely, we see that one can introduce coordinates into an abstract geometry. The theory of area is analyzed by cutting figures into triangles. The algebra of field extensions provides a method for deciding which geometrical constructions are possible. The investigation of the parallel postulate leads to the various non-Euclidean geometries. And ...

  13. History of analytic geometry

    CERN Document Server

    Boyer, Carl B

    2012-01-01

    Designed as an integrated survey of the development of analytic geometry, this study presents the concepts and contributions from before the Alexandrian Age through the eras of the great French mathematicians Fermat and Descartes, and on through Newton and Euler to the "Golden Age," from 1789 to 1850.

  14. Geometry and physics

    Science.gov (United States)

    Atiyah, Michael; Dijkgraaf, Robbert; Hitchin, Nigel

    2010-01-01

    We review the remarkably fruitful interactions between mathematics and quantum physics in the past decades, pointing out some general trends and highlighting several examples, such as the counting of curves in algebraic geometry, invariants of knots and four-dimensional topology. PMID:20123740

  15. Geometry and physics

    NARCIS (Netherlands)

    Atiyah, M.; Dijkgraaf, R.; Hitchin, N.

    2010-01-01

    We review the remarkably fruitful interactions between mathematics and quantum physics in the past decades, pointing out some general trends and highlighting several examples, such as the counting of curves in algebraic geometry, invariants of knots and four-dimensional topology.

  16. Algebraic geometry in India

    Indian Academy of Sciences (India)

    revolutionised by the introduction of new con- cepts and techniques by Grothendieck and others; this progress has been instrumental in solving outstanding and famous problems not only in algebraic geometry but also in related fields like number theory. Mathematicians from India have made influ- ential and extensive ...

  17. Origami, Geometry and Art

    Science.gov (United States)

    Wares, Arsalan; Elstak, Iwan

    2017-01-01

    The purpose of this paper is to describe the mathematics that emanates from the construction of an origami box. We first construct a simple origami box from a rectangular sheet and then discuss some of the mathematical questions that arise in the context of geometry and algebra. The activity can be used as a context for illustrating how algebra…

  18. Sliding vane geometry turbines

    Science.gov (United States)

    Sun, Harold Huimin; Zhang, Jizhong; Hu, Liangjun; Hanna, Dave R

    2014-12-30

    Various systems and methods are described for a variable geometry turbine. In one example, a turbine nozzle comprises a central axis and a nozzle vane. The nozzle vane includes a stationary vane and a sliding vane. The sliding vane is positioned to slide in a direction substantially tangent to an inner circumference of the turbine nozzle and in contact with the stationary vane.

  19. Proyeksi Geometri Fuzzy pada Ruang

    Directory of Open Access Journals (Sweden)

    Muhammad Izzat Ubaidillah

    2012-11-01

    Full Text Available Fuzzy geometry is an outgrowth of crisp geometry, which in crisp geometry elements are exist and not exist, but also while on fuzzy geometry elements are developed by thickness which is owned by each of these elements. Crisp projective geometries is the formation of a shadow of geometries element projected on the projectors element, with perpendicular properties which are represented by their respective elemental, the discussion focused on the results of the projection coordinates. While the fuzzy projective geometries have richer discussion, which includes about coordinates of projection results, the mutual relation of each element and the thickness of each element. This research was conducted to describe and analyzing procedure fuzzy projective geometries on the plane and explain the differences between crisp projective geometries and fuzzy projective geometries on plane.

  20. Supernumerary teeth "mesiodens". Case report.

    Science.gov (United States)

    Itro, A; Difalco, P

    2003-09-01

    The supernumerary tooth is an anomaly of dental eruption that is not rare to find in the clinical practice. Among the supernumerary teeth the "mesiodens" is most frequent. The mesiodens is found in the region of the superior central incisors and it can be the cause of many complications. The aim of this work is the description of a rare symptomatic case of mesiodens and the diagnostic and therapeutic strategies to adopt when this dental anomaly occurs. In particular the authors suggest making radiographic examinations only in the family of patients with dental anomalies of number, thinking that the incidence of such anomalies is too low to justify mass radiographic examinations.

  1. Supernumerary teeth in non-syndromic patients.

    Science.gov (United States)

    Mali, Santosh; Karjodkar, Freny Rashmiraj; Sontakke, Subodh; Sansare, Kaustubh

    2012-03-01

    Hyperdontia or supernumerary teeth without associated syndrome is a rare phenomenon, as supernumerary teeth are usually associated with cleft lip and palate or other syndromes such as Gardner's syndrome, cleidocranial dysplasia, and so on. Five patients with supernumerary teeth visited our department. They had no familial history or other pathology, certain treatment protocols was modified due to the presence of supernumerary teeth. Non-syndromic supernumerary teeth, if asymptomatic, need to have periodical radiographic observation. If they showed no variation as they impacted in the jaw, careful examination is necessary because they may develop into pathological status such as dentigerous cysts. The importance of a precise clinical history and radiographic examination for patients with multiple supernumerary teeth should be emphasized.

  2. Supernumerary teeth in non-syndromic patients

    Energy Technology Data Exchange (ETDEWEB)

    Mali, Santosh; Karjodkar, Freny Rashmiraj; Sontakke, Subodh; Sansare, Kaustubh [Nair Hospital Dental College, Maharashtra (India)

    2012-03-15

    Hyperdontia or supernumerary teeth without associated syndrome is a rare phenomenon, as supernumerary teeth are usually associated with cleft lip and palate or other syndromes such as Gardner's syndrome, cleidocranial dysplasia, and so on. Five patients with supernumerary teeth visited our department. They had no familial history or other pathology, certain treatment protocols was modified due to the presence of supernumerary teeth. Non-syndromic supernumerary teeth, if asymptomatic, need to have periodical radiographic observation. If they showed no variation as they impacted in the jaw, careful examination is necessary because they may develop into pathological status such as dentigerous cysts. The importance of a precise clinical history and radiographic examination for patients with multiple supernumerary teeth should be emphasized.

  3. Are teeth evidence in acid environment

    OpenAIRE

    Makesh Raj; Karen Boaz; N Srikant

    2013-01-01

    Aim: Teeth are the most durable structures that resist destruction more than skeletal tissue Commercially available acids can be used to destroy the body or a part, to mask human identification. The present study examines the effect of caustic acids on human dentition. Materials and Methods: Ten upper anterior teeth each were immersed in 37% hydrochloric acid (conc. HCl), 65% nitric acid (conc. HNO 3 ) and 96% sulfuric acid (conc. H 2 SO 4 ). Teeth were retrieved, washed in distilled water, d...

  4. A coding solution for supernumerary teeth.

    Science.gov (United States)

    van der Westhuijzen, A J; Morkel, J A

    2011-08-01

    In South Africa payments for treatment rendered are routinely delayed because of the medical fund industry's apparent inability to capture codes denoting supernumerary teeth. The suggested protocol allows for up to 13 supernumerary teeth to be identified by two digits. Meetings planned between SADA and key funding stakeholders to "ensure that protocols related to tooth numbering are acceptable", provide the ideal opportunity to introduce the suggested two-digit protocol for numbering supernumerary teeth. If this proposal is implemented, it could alleviate the frustration associated with the rejection of accounts where supernumerary teeth are appropriately identified.

  5. Transformational plane geometry

    CERN Document Server

    Umble, Ronald N

    2014-01-01

    Axioms of Euclidean Plane Geometry The Existence and Incidence Postulates The Distance and Ruler Postulates The Plane Separation Postulate The Protractor Postulate The Side-Angle-Side Postulate and the Euclidean Parallel Postulate Theorems of Euclidean Plane Geometry The Exterior Angle Theorem Triangle Congruence Theorems The Alternate Interior Angles Theorem and the Angle Sum Theorem Similar Triangles Introduction to Transformations, Isometries, and Similarities Transformations Isometries and SimilaritiesAppendix: Proof of Surjectivity Translations, Rotations, and Reflections Translations Rotations Reflections Appendix: Geometer's Sketchpad Commands Required by Exploratory Activities Compositions of Translations, Rotations, and Reflections The Three Points Theorem Rotations as Compositions of Two Reflections Translations as Compositions of Two Halfturns or Two Reflections The Angle Addition Theorem Glide Reflections Classification of Isometries The Fundamental Theorem and Congruence Classification of Isometr...

  6. Curved geometry and Graphs

    CERN Document Server

    Caravelli, Francesco

    2011-01-01

    Quantum Graphity is an approach to quantum gravity based on a background independent formulation of condensed matter systems on graphs. We summarize recent results obtained on the notion of emergent geometry from the point of view of a particle hopping on the graph. We discuss the role of connectivity in emergent Lorentzian perturbations in a curved background and the Bose--Hubbard (BH) model defined on graphs with particular symmetries.

  7. Algebra, Arithmetic, and Geometry

    CERN Document Server

    Tschinkel, Yuri

    2009-01-01

    The two volumes of "Algebra, Arithmetic, and Geometry: In Honor of Y.I. Manin" are composed of invited expository articles and extensions detailing Manin's contributions to the subjects, and are in celebration of his 70th birthday. The well-respected and distinguished contributors include: Behrend, Berkovich, Bost, Bressler, Calaque, Carlson, Chambert-Loir, Colombo, Connes, Consani, Dabrowski, Deninger, Dolgachev, Donaldson, Ekedahl, Elsenhans, Enriques, Etingof, Fock, Friedlander, Geemen, Getzler, Goncharov, Harris, Iskovskikh, Jahnel, Kaledin, Kapranov, Katz, Kaufmann, Kollar, Kont

  8. Emergent geometry, emergent forces

    Science.gov (United States)

    Selesnick, S. A.

    2017-10-01

    We give a brief account of some aspects of Finkelstein’s quantum relativity, namely an extension of it that derives elements of macroscopic geometry and the Lagrangians of the standard model including gravity from a presumed quantum version of spacetime. These emerge as collective effects in this quantal substrate. Our treatment, which is largely self-contained, differs mathematically from that originally given by Finkelstein. Dedicated to the memory of David Ritz Finkelstein

  9. Integral geometry and valuations

    CERN Document Server

    Solanes, Gil

    2014-01-01

    Valuations are finitely additive functionals on the space of convex bodies. Their study has become a central subject in convexity theory, with fundamental applications to integral geometry. In the last years there has been significant progress in the theory of valuations, which in turn has led to important achievements in integral geometry. This book originated from two courses delivered by the authors at the CRM and provides a self-contained introduction to these topics, covering most of the recent advances. The first part, by Semyon Alesker, is devoted to the theory of convex valuations, with emphasis on the latest developments. A special focus is put on the new fundamental structures of the space of valuations discovered after Alesker's irreducibility theorem. Moreover, the author describes the newly developed theory of valuations on manifolds. In the second part, Joseph H. G. Fu gives a modern introduction to integral geometry in the sense of Blaschke and Santaló, based on the notions and tools presented...

  10. Emergent complex network geometry.

    Science.gov (United States)

    Wu, Zhihao; Menichetti, Giulia; Rahmede, Christoph; Bianconi, Ginestra

    2015-05-18

    Networks are mathematical structures that are universally used to describe a large variety of complex systems such as the brain or the Internet. Characterizing the geometrical properties of these networks has become increasingly relevant for routing problems, inference and data mining. In real growing networks, topological, structural and geometrical properties emerge spontaneously from their dynamical rules. Nevertheless we still miss a model in which networks develop an emergent complex geometry. Here we show that a single two parameter network model, the growing geometrical network, can generate complex network geometries with non-trivial distribution of curvatures, combining exponential growth and small-world properties with finite spectral dimensionality. In one limit, the non-equilibrium dynamical rules of these networks can generate scale-free networks with clustering and communities, in another limit planar random geometries with non-trivial modularity. Finally we find that these properties of the geometrical growing networks are present in a large set of real networks describing biological, social and technological systems.

  11. Natal teeth - Two Case Reports | Kahabuka | Tanzania Dental Journal

    African Journals Online (AJOL)

    Natal teeth are the teeth present in the mouth at birth where as neonatal teeth erupt during the first month of life. Occurrence of these teeth is rare and when they occur, they cause apprehension to parents. For centuries, these teeth have been associated with diverse superstition and folklore or myths. The aim of this report is ...

  12. Geometry success in 20 mins

    CERN Document Server

    Editors, LearningExpress

    2010-01-01

    Whether you're new to geometry or just looking for a refresher, this completely revised and updated third edition of Geometry Success in 20 Minutes a Day offers a 20-step lesson plan that provides quick and thorough instruction in practical, critical skills. Stripped of unnecessary math jargon but bursting with geometry essentials, Geometry Success in 20 Minutes a Day is an invaluable resource for both students and adults.

  13. Supernumerary teeth in a Turkish population.

    Science.gov (United States)

    Esenlik, Elçin; Sayin, M Ozgür; Atilla, A Onur; Ozen, Tuncer; Altun, Ceyhan; Başak, Feridun

    2009-12-01

    Our aim in this study was to investigate the frequency, distribution, sex differences, and characteristics of supernumerary teeth in a referred Turkish population. A total of 2599 patients' panoramic radiographs (1360 girls, 1239 boys) were evaluated, including children in both the mixed and the permanent dentitions. Their mean age was 8.6 +/- 0.23 years. Number, location, classification, side, and impaction of supernumerary teeth were evaluated. Furthermore, the development of these teeth was evaluated. Eighty-four supernumerary teeth were found on 69 radiographs; 9 were deciduous and 75 were permanent teeth. Most supernumerary teeth were in the premaxillary region (67%). Mesiodens (n = 43) was the most frequent supernumerary tooth (51.2%). This was followed by the maxillary lateral incisor (15.5%), the mandibular premolar (14.3%), the maxillary canine (9.5%), the maxillary premolar (6%), the mandibular lateral incisor (2.4%), and the mandibular canine (1.2%). Sixty-two (73.8%) supernumerary teeth were impacted. The male-female ratio was 1.13:1, which was not statistically significant. The prevalence of supernumerary teeth in Turkish children was 2.7% in this study.

  14. Coronal tissue loss in endodontically treated teeth.

    Science.gov (United States)

    Sulaiman, A O; Shaba, O P; Dosumu, O O; Ajayi, D M

    2012-12-01

    To categorize the endodontically treated teeth according to the extent of coronal tissue loss in order to determine the appropriate restoration required. A two year descriptive study was done at the Conservative Clinic of the Department of Restorative Dentistry, Dental Centre, University College Hospital, Ibadan. Successful endodontically treated teeth were assessed and categorized according to the extent of tissue loss based on standard criteria proposed by Smith and Schuman. Two hundred and ninety endodontically treated teeth were assessed for success both clinically and radiographically. Eighty (27.6%) were anterior teeth, 78 (26.9%) were premolars while 132 (45.5%) were molars. Dental caries was found to be the most common (61.4%) indication for endodontic treatment and caused more coronal tissue damage (moderate and significant) when compared with other indications for endodontic treatment. Two hundred and twenty seven (78.3%) endodontically treated teeth had moderate coronal tissue loss, 41 (14.1%) had minimal damage while 22 (7.6%) had significant tissue damage. Dental caries was the most common indication for endodontic treatment of the posterior teeth while trauma was the most common indication for the anterior teeth. Majority of the endodontically treated teeth that were evaluated for tissue loss had moderate coronal tissue damage. It is therefore recommended that proper and prompt evaluation of the remaining coronal tooth tissue following successful endodontic treatment be carried out in order to determine the appropriate definitive restoration required that will be easy for the clinician and less expensive to the patients.

  15. Take Care of Your Teeth and Gums

    Science.gov (United States)

    ... can lead to tooth decay and gum disease. Brushing and flossing help get plaque off your teeth so your mouth can stay healthy. Taking care of your teeth and gums is especially important if you: Have diabetes Have cancer Are an ...

  16. Crouzon syndrome with multiple supernumerary teeth | Torun ...

    African Journals Online (AJOL)

    Although hypodontia is usually present in cases with CS, supernumerary teeth are rarely seen. A 16‑year‑old male patient with CS was referred to our clinic. He had a high forehead, beaked nose, hypertelorism, palpebral ptosis, and asymmetrical orbits. Bilateral multiple supernumerary teeth were observed in his upper and ...

  17. Fracture resistance of tooth restored with four glass fiber post systems of varying surface geometries: an in vitro study

    OpenAIRE

    Jayasenthil, Adhikesavan; Solomon-Sathish, Emmanuel; Venkatalakshmi-Aparna, Potluri; Balagopal, Sunderasan

    2016-01-01

    Background The purpose of this study was to relate the fracture resistance of endodontically treated teeth in relation to post geometry. Material and Methods Forty single rooted mandibular premolars were instrumented by step - back technique and obturated by lateral condensation. Forty teeth were randomly divided into four groups: Reforpost glass fiber X-ray?, RelyX?, Exacto conical? and Parapost Fiber Lux?. The post spaces were prepared using respective drills and luted. The core build up wa...

  18. Graded geometry and Poisson reduction

    OpenAIRE

    Cattaneo, A S; Zambon, M

    2009-01-01

    The main result of [2] extends the Marsden-Ratiu reduction theorem [4] in Poisson geometry, and is proven by means of graded geometry. In this note we provide the background material about graded geometry necessary for the proof in [2]. Further, we provide an alternative algebraic proof for the main result. ©2009 American Institute of Physics

  19. Teaching of Geometry in Bulgaria

    Science.gov (United States)

    Bankov, Kiril

    2013-01-01

    Geometry plays an important role in the school mathematics curriculum all around the world. Teaching of geometry varies a lot (Hoyls, Foxman, & Kuchemann, 2001). Many countries revise the objectives, the content, and the approaches to the geometry in school. Studies of the processes show that there are not common trends of these changes…

  20. Geometry I essentials

    CERN Document Server

    REA, The Editors of

    2012-01-01

    REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Geometry I includes methods of proof, points, lines, planes, angles, congruent angles and line segments, triangles, parallelism, quadrilaterals, geometric inequalities, and geometric

  1. Elementary algebraic geometry

    CERN Document Server

    Kendig, Keith

    2015-01-01

    Designed to make learning introductory algebraic geometry as easy as possible, this text is intended for advanced undergraduates and graduate students who have taken a one-year course in algebra and are familiar with complex analysis. This newly updated second edition enhances the original treatment's extensive use of concrete examples and exercises with numerous figures that have been specially redrawn in Adobe Illustrator. An introductory chapter that focuses on examples of curves is followed by a more rigorous and careful look at plane curves. Subsequent chapters explore commutative ring th

  2. Geometry of conics

    CERN Document Server

    Akopyan, A V

    2007-01-01

    The book is devoted to the properties of conics (plane curves of second degree) that can be formulated and proved using only elementary geometry. Starting with the well-known optical properties of conics, the authors move to less trivial results, both classical and contemporary. In particular, the chapter on projective properties of conics contains a detailed analysis of the polar correspondence, pencils of conics, and the Poncelet theorem. In the chapter on metric properties of conics the authors discuss, in particular, inscribed conics, normals to conics, and the Poncelet theorem for confoca

  3. From geometry to topology

    CERN Document Server

    Flegg, H Graham

    2001-01-01

    This excellent introduction to topology eases first-year math students and general readers into the subject by surveying its concepts in a descriptive and intuitive way, attempting to build a bridge from the familiar concepts of geometry to the formalized study of topology. The first three chapters focus on congruence classes defined by transformations in real Euclidean space. As the number of permitted transformations increases, these classes become larger, and their common topological properties become intuitively clear. Chapters 4-12 give a largely intuitive presentation of selected topics.

  4. Geometry of numbers

    CERN Document Server

    Gruber, Peter M

    1987-01-01

    This volume contains a fairly complete picture of the geometry of numbers, including relations to other branches of mathematics such as analytic number theory, diophantine approximation, coding and numerical analysis. It deals with convex or non-convex bodies and lattices in euclidean space, etc.This second edition was prepared jointly by P.M. Gruber and the author of the first edition. The authors have retained the existing text (with minor corrections) while adding to each chapter supplementary sections on the more recent developments. While this method may have drawbacks, it has the definit

  5. Kinematic geometry of gearing

    CERN Document Server

    Dooner, David B

    2012-01-01

    Building on the first edition published in 1995 this new edition of Kinematic Geometry of Gearing has been extensively revised and updated with new and original material. This includes the methodology for general tooth forms, radius of torsure', cylinder of osculation, and cylindroid of torsure; the author has also completely reworked the '3 laws of gearing', the first law re-written to better parallel the existing 'Law of Gearing" as pioneered by Leonard Euler, expanded from Euler's original law to encompass non-circular gears and hypoid gears, the 2nd law of gearing describing a unique relat

  6. Local analytic geometry

    CERN Document Server

    Abhyankar, Shreeram Shankar

    1964-01-01

    This book provides, for use in a graduate course or for self-study by graduate students, a well-motivated treatment of several topics, especially the following: (1) algebraic treatment of several complex variables; (2) geometric approach to algebraic geometry via analytic sets; (3) survey of local algebra; (4) survey of sheaf theory. The book has been written in the spirit of Weierstrass. Power series play the dominant role. The treatment, being algebraic, is not restricted to complex numbers, but remains valid over any complete-valued field. This makes it applicable to situations arising from

  7. Geometry and trigonometry

    CERN Document Server

    2015-01-01

    This stimulating volume offers a broad collection of the principles of geometry and trigonometry and contains colorful diagrams to bring mathematical principles to life. Subjects are enriched by references to famous mathematicians and their ideas, and the stories are presented in a very comprehensible way. Readers investigate the relationships of points, lines, surfaces, and solids. They study construction methods for drawing figures, a wealth of facts about these figures, and above all, methods to prove the facts. They learn about triangle measure for circular motion, sine and cosine, tangent

  8. New foundations for geometry

    OpenAIRE

    Haran, Shai

    2015-01-01

    We shall describe a simple generalization of commutative rings. The category GR of such "rings", contains the ordinary commutative rings (fully faithfully), but also the "integers" and "residue field" at a real or complex place of a field ; the "field with one element" (the initial object of GR ); the "arithmetical surface" ( the sum in the category GR of the integers with them self: Z(x)Z ) . We shall show that this geometry "see" the real and complex places of a number field (there is an Os...

  9. Concrescent triplets involving primary anterior teeth

    Directory of Open Access Journals (Sweden)

    Urvashi Sharma

    2013-01-01

    Full Text Available Odontogenesis is a complex process wherein more than 200 genes are known to play a significant role in tooth development. An imbalance can lead to an abnormality in the number, size, shape or structure of the developing tooth/teeth. The presence of an extra dental lamina forms a supernumerary tooth. The supernumerary teeth are of two types: A rudimentary tooth where the supernumerary tooth does not resemble any tooth in the normal series or a supplemental tooth in which this anomalous tooth resembles one in the normal series. It is also very rare to encounter triple teeth in primary dentition. The union of these teeth may be through fusion, gemination, concrescence or a combination of fusion and gemination. Presented is a rare case of concrescence involving maxillary deciduous incisors and a supplemental tooth in a 7-year-old boy. The differential diagnosis, etiology, and complications of primary anterior triple teeth are discussed.

  10. Automatic teeth axes calculation for well-aligned teeth using cost profile analysis along teeth center arch.

    Science.gov (United States)

    Kim, Gyehyun; Lee, Jeongjin; Seo, Jinwook; Lee, Wooshik; Shin, Yeong-Gil; Kim, Bohyoung

    2012-04-01

    In dental implantology and virtual dental surgery planning using computed tomography (CT) images, the examination of the axes of neighboring and/or biting teeth is important to improve the performance of the masticatory system as well as the aesthetic beauty. However, due to its high connectivity to neighboring teeth and jawbones, a tooth and/or its axis is very elusive to automatically identify in dental CT images. This paper presents a novel method of automatically calculating individual teeth axes. The planes separating the individual teeth are automatically calculated using cost profile analysis along the teeth center arch. In this calculation, a novel plane cost function, which considers the intensity and the gradient, is proposed to favor the teeth separation planes crossing the teeth interstice and suppress the possible inappropriately detected separation planes crossing the soft pulp. The soft pulp and dentine of each individually separated tooth are then segmented by a fast marching method with two newly proposed speed functions considering their own specific anatomical characteristics. The axis of each tooth is finally calculated using principal component analysis on the segmented soft pulp and dentine. In experimental results using 20 clinical datasets, the average angle and minimum distance differences between the teeth axes manually specified by two dentists and automatically calculated by the proposed method were 1.94° ± 0.61° and 1.13 ± 0.56 mm, respectively. The proposed method identified the individual teeth axes accurately, demonstrating that it can give dentists substantial assistance during dental surgery such as dental implant placement and orthognathic surgery.

  11. Fracture resistance of posterior teeth restored with modern restorative materials.

    Science.gov (United States)

    Hamouda, Ibrahim M; Shehata, Salah H

    2011-11-01

    We studied the fracture resistance of maxillary premolars restored with recent restorative materials. Fifty maxillary premolars were divided into five groups: Group 1 were unprepared teeth; Group 2 were teeth prepared without restoration; Group 3 were teeth restored with tetric ceram HB; Group 4 were teeth restored with InTen S; and Group 5 were teeth restored with Admira. The samples were tested using a universal testing machine. Peak loads at fracture were recorded. The teeth restored with Admira had the highest fracture resistance followed by those restored with InTen-S and tetric ceram HB. Prepared, unrestored teeth were the weakest group. There was a significant difference between the fracture resistance of intact teeth and the prepared, unrestored teeth. There was also a significant difference among the tested restorative materials. Teeth restored with Admira showed no significant difference when compared with the unprepared teeth. It was concluded that the teeth restored with Admira exhibited the highest fracture resistance.

  12. Orthodontics Align Crooked Teeth and Boost Self-Esteem

    Science.gov (United States)

    ... desktop! more... Orthodontics Align Crooked Teeth and Boost Self- esteem Article Chapters Orthodontics Align Crooked Teeth and Boost Self- esteem print full article print this chapter email this ...

  13. Real algebraic geometry

    CERN Document Server

    Bochnak, Jacek; Roy, Marie-Françoise

    1998-01-01

    This book is a systematic treatment of real algebraic geometry, a subject that has strong interrelation with other areas of mathematics: singularity theory, differential topology, quadratic forms, commutative algebra, model theory, complexity theory etc. The careful and clearly written account covers both basic concepts and up-to-date research topics. It may be used as text for a graduate course. The present edition is a substantially revised and expanded English version of the book "Géometrie algébrique réelle" originally published in French, in 1987, as Volume 12 of ERGEBNISSE. Since the publication of the French version the theory has made advances in several directions. Many of these are included in this English version. Thus the English book may be regarded as a completely new treatment of the subject.

  14. Complex geometries in wood

    DEFF Research Database (Denmark)

    Tamke, Martin; Ramsgaard Thomsen, Mette; Riiber Nielsen, Jacob

    2009-01-01

    The versatility of wood constructions and traditional wood joints for the production of non standard elements was in focus of a design based research. Herein we established a seamless process from digital design to fabrication. A first research phase centered on the development of a robust parame...... parametric model and a generic design language a later explored the possibilities to construct complex shaped geometries with self registering joints on modern wood crafting machines. The research was carried out as collaboration with industrial partners.......The versatility of wood constructions and traditional wood joints for the production of non standard elements was in focus of a design based research. Herein we established a seamless process from digital design to fabrication. A first research phase centered on the development of a robust...

  15. [Post and core for endodontically treated teeth].

    Science.gov (United States)

    Labropoulou-Tzortzopoulou, E

    1990-01-01

    The literature is replete with the various techniques used in the restoration of pulpless teeth. Controversies surround the most clinically successful procedures and general dentist is confronted daily with the dilemma of choosing the best treatment modality. Endodontically treated posterior teeth present restorative problems. The remaining tooth tissue requires special treatment to prevent further destruction. This report presents an effective method for succeeding extension and protection for endodontically treated teeth. The advantages of the post-core system against other types of restoration, as well the indications are reviewed. In this paper the preparation of the tooth and the construction of a post-core by the direct and indirect method are described.

  16. An introduction to incidence geometry

    CERN Document Server

    De Bruyn, Bart

    2016-01-01

    This book gives an introduction to the field of Incidence Geometry by discussing the basic families of point-line geometries and introducing some of the mathematical techniques that are essential for their study. The families of geometries covered in this book include among others the generalized polygons, near polygons, polar spaces, dual polar spaces and designs. Also the various relationships between these geometries are investigated. Ovals and ovoids of projective spaces are studied and some applications to particular geometries will be given. A separate chapter introduces the necessary mathematical tools and techniques from graph theory. This chapter itself can be regarded as a self-contained introduction to strongly regular and distance-regular graphs. This book is essentially self-contained, only assuming the knowledge of basic notions from (linear) algebra and projective and affine geometry. Almost all theorems are accompanied with proofs and a list of exercises with full solutions is given at the end...

  17. Supernumerary teeth: Report of four unusual cases

    Directory of Open Access Journals (Sweden)

    Arun Kumar

    2012-01-01

    Full Text Available Supernumerary tooth denotes duplication of tooth in the normal series. It is a developmental anomaly and has been argued to arise from multiple etiologies. These teeth may remain embedded in the alveolar bone or can erupt into the oral cavity. The supernumerary tooth might cause esthetic and/or functional problems, especially if it is situated in the maxillary anterior region. Complications reported were delayed or prevented eruption of succedaneous teeth, displacement or rotation, crowding of the affected region, abnormal diastema, dilacerations, cystic formation, and sometime eruption into the nasal cavity. In this case report, four unusual cases of supernumerary teeth that resulted in varying degrees of disturbances in permanent dentition are presented. Conservative surgical intervention and light orthodontic forces were used to bring the teeth into normal position with minimal disturbance to the surrounding oral structures.

  18. How to Care for Your Baby's Teeth

    Science.gov (United States)

    ... editorial staffCroupMarch 2017September 2000Infants and Toddlersfamilydoctor.org editorial staff Home Family Health Infants and Toddlers Dental Hygiene: How to Care for Your Baby’s Teeth Dental ...

  19. Supernumerary teeth: Report of four unusual cases.

    Science.gov (United States)

    Kumar, Arun; Namdev, Ritu; Bakshi, Lokesh; Dutta, Samir

    2012-04-01

    Supernumerary tooth denotes duplication of tooth in the normal series. It is a developmental anomaly and has been argued to arise from multiple etiologies. These teeth may remain embedded in the alveolar bone or can erupt into the oral cavity. The supernumerary tooth might cause esthetic and/or functional problems, especially if it is situated in the maxillary anterior region. Complications reported were delayed or prevented eruption of succedaneous teeth, displacement or rotation, crowding of the affected region, abnormal diastema, dilacerations, cystic formation, and sometime eruption into the nasal cavity. In this case report, four unusual cases of supernumerary teeth that resulted in varying degrees of disturbances in permanent dentition are presented. Conservative surgical intervention and light orthodontic forces were used to bring the teeth into normal position with minimal disturbance to the surrounding oral structures.

  20. Laser and LED external teeth-bleaching

    Science.gov (United States)

    Zanin, Fatima A.; Brugnera, Aldo, Jr.; Marchesan, Melissa A.; Pecora, Jesus D.

    2004-09-01

    Teeth-bleaching is an initial phase in the reproduction of an aesthetic smile; thus, it is very important that the dentist knows how to diagnose the causes of color changes and indicate whitening before proposing dental treatment. Technological advances in teeth-whitening lead to the development of new techniques, improving comfort, security and decreasing time of execution: argon laser, diode Laser, LED whitening, xenon light whitening. The clearing agent used in all techniques, including home whitening, is hydrogen peroxide (H2O2) in different concentrations. In this study, the authors describe mechanisms of gel activation, the use of Laser and LED"s for teeth-bleaching, the importance of diagnosis and the comfort of the patient in in-office teeth-bleaching techniques.

  1. Taurodontism in association with supernumerary teeth.

    Science.gov (United States)

    Genc, A; Namdar, F; Goker, K; Atasu, M

    1999-01-01

    The dental, radiological, genetic and dermatoglyphic findings of an additional patient with taurodontism in association with supernumerary teeth were presented and the findings of the patient were compared with those in the literature.

  2. Bruxism (Teeth Grinding or Clenching) (For Parents)

    Science.gov (United States)

    ... Late for the Flu Vaccine? Eating Disorders Arrhythmias Bruxism (Teeth Grinding or Clenching) KidsHealth > For Parents > Bruxism ( ... called bruxism , which is common in kids. About Bruxism Bruxism is the medical term for the grinding ...

  3. Thermodynamics of Asymptotically Conical Geometries.

    Science.gov (United States)

    Cvetič, Mirjam; Gibbons, Gary W; Saleem, Zain H

    2015-06-12

    We study the thermodynamical properties of a class of asymptotically conical geometries known as "subtracted geometries." We derive the mass and angular momentum from the regulated Komar integral and the Hawking-Horowitz prescription and show that they are equivalent. By deriving the asymptotic charges, we show that the Smarr formula and the first law of thermodynamics hold. We also propose an analog of Christodulou-Ruffini inequality. The analysis can be generalized to other asymptotically conical geometries.

  4. Self-designing parametric geometries

    OpenAIRE

    Sobester, Andras

    2015-01-01

    The thesis of this paper is that script-based geometry modelling offers the possibility of building `self-designing' intelligence into parametric airframe geometries. We show how sophisticated heuristics (such as optimizers and complex decision structures) can be readily integrated into the parametric geometry model itself using a script-driven modelling architecture. The result is an opportunity for optimization with the scope of conceptual design and the fidelity of preliminary design. Addi...

  5. Geometry aware Stationary Subspace Analysis

    Science.gov (United States)

    2016-11-22

    JMLR: Workshop and Conference Proceedings 63:430–444, 2016 ACML 2016 Geometry -aware Stationary Subspace Analysis Inbal Horev inbal@ms.k.u-tokyo.ac.jp... geometry of the SPD matrix manifold and the invariance properties of its metrics. Most notably we show that these invariances alleviate the need to...Horev, F. Yger & M. Sugiyama. Geometry -aware SSA many theoretical and practical aspects have been addressed (see Sugiyama and Kawanabe (2012) for an in

  6. Planetary Image Geometry Library

    Science.gov (United States)

    Deen, Robert C.; Pariser, Oleg

    2010-01-01

    The Planetary Image Geometry (PIG) library is a multi-mission library used for projecting images (EDRs, or Experiment Data Records) and managing their geometry for in-situ missions. A collection of models describes cameras and their articulation, allowing application programs such as mosaickers, terrain generators, and pointing correction tools to be written in a multi-mission manner, without any knowledge of parameters specific to the supported missions. Camera model objects allow transformation of image coordinates to and from view vectors in XYZ space. Pointing models, specific to each mission, describe how to orient the camera models based on telemetry or other information. Surface models describe the surface in general terms. Coordinate system objects manage the various coordinate systems involved in most missions. File objects manage access to metadata (labels, including telemetry information) in the input EDRs and RDRs (Reduced Data Records). Label models manage metadata information in output files. Site objects keep track of different locations where the spacecraft might be at a given time. Radiometry models allow correction of radiometry for an image. Mission objects contain basic mission parameters. Pointing adjustment ("nav") files allow pointing to be corrected. The object-oriented structure (C++) makes it easy to subclass just the pieces of the library that are truly mission-specific. Typically, this involves just the pointing model and coordinate systems, and parts of the file model. Once the library was developed (initially for Mars Polar Lander, MPL), adding new missions ranged from two days to a few months, resulting in significant cost savings as compared to rewriting all the application programs for each mission. Currently supported missions include Mars Pathfinder (MPF), MPL, Mars Exploration Rover (MER), Phoenix, and Mars Science Lab (MSL). Applications based on this library create the majority of operational image RDRs for those missions. A

  7. Hypersensitive teeth. Part II: Treatment.

    Science.gov (United States)

    Krauser, J T

    1986-09-01

    If the hydrodynamic theory for pain transmission were accepted, occlusion of the patent dentinal tubules would appear to be essential for treatment efficacy. There are many compounds with seemingly varied chemical forms that have been shown to be effective. Their exact mode of action however, is not clearly defined because well-designed, nonbiased, and controlled comparison studies between agents are lacking. The various toothpastes may have ingredients that actually occlude patent tubules or they may cause secondary desensitization by irrational or abrasive action. In any pain study, the nature of the placebo effect and other psychogenic factors play a significant role. Fluoride preparation with and without iontophoresis has been shown to alter tubule structure and form microprecipitates. The natural desensitization process, although slow, is nature's protection, allowing dentinal sclerosis of secondary dentin formation. Although the resin-adhesive systems, especially the new light-cured dentin bonding agents, appear immediately to be effective, the effect on the pulp remains unknown. Perhaps a combination of iontophoresis with sodium fluoride and light-cured dentin bonding material may yield protection and desensitization at a high level of predictability. With the population trends toward a more geriatric society, further research, knowledge, and understanding of dentinal hypersensitivity is of paramount importance. The expected increase in longevity of the dentition suggests that dentin exposure and sensitivity will increase as a clinical problem. There is a clear time-age relationship involved in gingival recession, erosion and attrition of the teeth, and the need for periodontal surgical therapy. For total comprehensive care, patient comfort is important and should be provided along with sound periodontal health and ideal restorative function.

  8. Retrospective study of 145 supernumerary teeth

    OpenAIRE

    Fernández Montenegro, Paula; Valmaseda Castellón, E.; Berini Aytés, Leonardo; Gay Escoda, Cosme

    2006-01-01

    Objective: The goal of the present retrospective study is to describe the distribution of the supernumerary teeth in a population of patients that have been attended at the Public Clinic of the Department of Oral Surgery. Background: Supernumerary teeth and multiple hyperdontia are usually associated with different syndromes, such as Gardner syndrome, or with facial fissures; however, they can appear in patients without any pathology. Their prevalence oscillates to 0.5-3.8% in patients wi...

  9. Retrospective study of 145 supernumerary teeth

    OpenAIRE

    Fernández Montenegro, Paula; Valmaseda Castellón, Eduardo; Berini Aytés, Leonardo; Gay Escoda, Cosme

    2006-01-01

    Objective: The goal of the present retrospective study is to describe the distribution of the supernumerary teeth in a population of patients that have been attended at the Public Clinic of the Department of Oral Surgery. Background: Supernumerary teeth and multiple hyperdontia are usually associated with different syndromes, such as Gardner syndrome, or with facial fissures; however, they can appear in patients without any pathology. Their prevalence oscillates to 0.5-3.8% in patients with p...

  10. Drug-induced disorders of teeth.

    Science.gov (United States)

    Tredwin, C J; Scully, C; Bagan-Sebastian, J-V

    2005-07-01

    It is essential that every health care professional who is involved with the prescription or recommendation of drugs be fully aware of any resultant disorders that may arise as a side-effect. A range of drugs can affect the teeth. In this review article, drugs that have the potential to induce changes in teeth have been classified as those leading to tooth discoloration (intrinsic and extrinsic), physical damage to tooth structure (enamel, dentin, and cementum), and alteration in tooth sensitivity.

  11. Reconstruction of endodontically treated teeth: intraradicular retainers

    OpenAIRE

    Luciano Bonatelli Bispo

    2008-01-01

    There are many ways of restoring endodontically treated teeth. The quantity and quality of the dental remainder after endodontic treatment is questionable in terms of clinical longevity, not because of the coronal opening and therapy in themselves, but because of the destruction inherent to teeth affected by fractures and invasive carious processes. There are many commercial brands of posts and marketing artifices with the goal of maximizing resistance to masticatory forces. However, the majo...

  12. Initiation to global Finslerian geometry

    CERN Document Server

    Akbar-Zadeh, Hassan

    2006-01-01

    After a brief description of the evolution of thinking on Finslerian geometry starting from Riemann, Finsler, Berwald and Elie Cartan, the book gives a clear and precise treatment of this geometry. The first three chapters develop the basic notions and methods, introduced by the author, to reach the global problems in Finslerian Geometry. The next five chapters are independent of each other, and deal with among others the geometry of generalized Einstein manifolds, the classification of Finslerian manifolds of constant sectional curvatures. They also give a treatment of isometric, affine, p

  13. Straight, white teeth as a social prerogative.

    Science.gov (United States)

    Khalid, Abeer; Quiñonez, Carlos

    2015-06-01

    A distinguishing feature of North American society is preoccupation with self-image, as seen in the ritualistic nature of bodily practices aimed at constantly improving the body. Nowhere is this more apparent than in the prevailing fixation with straight, white teeth. While there is an ever-expanding literature on the sociology of body, very little has been written on teeth in this context. Using literature from anthropology, biology, dentistry, sociology and social psychology, this study attempts to answer: (1) Why have straight, white teeth become a beauty ideal in North American society? (2) What is the basis for this ideal? (3) How is this ideal propagated? It demonstrates that dental aesthetic tendencies are biologically, culturally and socially patterned. Concepts from the works of Pierre Bourdieu and Michel Foucault are used to illustrate how straight, white teeth contribute towards reinforcing class differences and how society exercises a disciplinary power on individuals through this ideal. It is concluded that modified teeth are linked to self and identity that are rooted in social structure. Moreover, teeth demonstrate the ways in which class differences are embodied and projected as symbols of social advantage or disadvantage. Implications on professional, public health, sociological and political levels are considered. © 2015 Foundation for the Sociology of Health & Illness.

  14. Coevolutionary patterning of teeth and taste buds.

    Science.gov (United States)

    Bloomquist, Ryan F; Parnell, Nicholas F; Phillips, Kristine A; Fowler, Teresa E; Yu, Tian Y; Sharpe, Paul T; Streelman, J Todd

    2015-11-03

    Teeth and taste buds are iteratively patterned structures that line the oro-pharynx of vertebrates. Biologists do not fully understand how teeth and taste buds develop from undifferentiated epithelium or how variation in organ density is regulated. These organs are typically studied independently because of their separate anatomical location in mammals: teeth on the jaw margin and taste buds on the tongue. However, in many aquatic animals like bony fishes, teeth and taste buds are colocalized one next to the other. Using genetic mapping in cichlid fishes, we identified shared loci controlling a positive correlation between tooth and taste bud densities. Genome intervals contained candidate genes expressed in tooth and taste bud fields. sfrp5 and bmper, notable for roles in Wingless (Wnt) and bone morphogenetic protein (BMP) signaling, were differentially expressed across cichlid species with divergent tooth and taste bud density, and were expressed in the development of both organs in mice. Synexpression analysis and chemical manipulation of Wnt, BMP, and Hedgehog (Hh) pathways suggest that a common cichlid oral lamina is competent to form teeth or taste buds. Wnt signaling couples tooth and taste bud density and BMP and Hh mediate distinct organ identity. Synthesizing data from fish and mouse, we suggest that the Wnt-BMP-Hh regulatory hierarchy that configures teeth and taste buds on mammalian jaws and tongues may be an evolutionary remnant inherited from ancestors wherein these organs were copatterned from common epithelium.

  15. Nonsyndromic multiple supernumerary teeth: A case report of 11 supernumerary teeth

    OpenAIRE

    Balaji Krishnan; Balaji Narasimhan; C Nirupama

    2012-01-01

    Hyperdontia is an odontostomatologic anomaly characterized by an excess in both erupted and non-erupted teeth number. A23-year-old female patient reported to us with a chief complaint of malaligned teeth and inability to maintain oral hygiene. Extraoral examination did not reveal any abnormality. Intraoral examination revealed multiple supernumerary teeth in maxillary and mandibular premolar region. The teeth present were: 11, 12,13,14,16,17,18.21,22,23,24,25,26,27,28,31,32,33, 34, 35. 36, 37...

  16. Non-syndromic supernumerary teeth: report of a case with 6 supernumerary teeth

    Directory of Open Access Journals (Sweden)

    Taghibakhsh M

    2011-02-01

    Full Text Available "nBackground and Aims: Multiple supernumerary teeth are rare and often found in association with syndromes such as Gardner, Cleidocranial dysplasia and cleft lip and palate, with a much less chance for isolated"nnon-syndromic cases. The aim of this study was to report a case with 6 supernumerary teeth without syndromic association."nCase Report: The patient was a 33 year-old female, referred to oral diseases and diagnosis department with chief complaint of sensitivity to cold and hot food in right upper premolar region. Oral examination revealed 5 erupted lingually supernumerary teeth (four in mandibular and one in maxillary premolar region, respectively. Further panoramic radiography clarified an extra impacted tooth in the palatal region of left premolar maxillary area. All extra teeth had been appeared since the age of 17 during one year, as the patient claimed. Medical history and thorough clinical and paraclinical examinations were not significant except for the hypothyroidism, since 5 years ago. No other family member noticed to be the case. Based on our findings, a diagnosis of non-syndromic multiple supernumerary teeth was established."nConclusion: A thorough examination of each patient presented with supernumerary teeth, including panoramic and intraoral radiographic images may provide valuable information regarding accompanying syndromes and unerupted teeth. Early diagnosis is an essential step for orthodontic or surgical decisions making, preventing or avoiding worsening complications such as malocclusion, adjacent normal teeth delayed eruption or rotation, diasthema, cystic lesions and resorption of contiguous teeth.

  17. Color From Geometry

    CERN Document Server

    Guijosa, A

    1999-01-01

    This thesis explores some aspects of the recently uncovered connection between gauge theories and gravity, known as the AdS/CFT, or bulk-boundary, correspondence. This is a remarkable statement of equivalence between string or M-theory on certain backgrounds and field theories living on the boundaries of the corresponding spacetimes. Under the duality between four-dimensional N = 4 SU(N) superYang-Mills (SYM) and Type IIB string theory on AdS5 × S5, a baryon is mapped onto N fundamental strings terminating on a wrapped D5-brane. We examine the structure and energetics of this system from the vantage point of the fivebrane worldvolume action, making use of the Born-Infeld string approach. We construct supersymmetric fivebrane embeddings which correspond to gauge theory configurations with n external quarks, 0 ≤ n ≤ N. The extension of these solutions to the full asymptotically flat geometry of N D3-branes provides a detailed description of the creation of strings as the fivebrane is...

  18. Ostrich eggs geometry

    Directory of Open Access Journals (Sweden)

    Šárka Nedomová

    2013-01-01

    Full Text Available Precise quantification of the profile of egg can provide a powerful tool for the analysis of egg shape for various biological problems. A new approach to the geometry of a Ostrich’s egg profile is presented here using an analysing the egg’s digital photo by edge detection techniques. The obtained points on the eggshell counter are fitted by the Fourier series. The obtained equations describing an egg profile have been used to calculate radii of curvature. The radii of the curvature at the important point of the egg profile (sharp end, blunt end and maximum thickness are independent on the egg shape index. The exact values of the egg surface and the egg volume have been obtained. These quantities are also independent on the egg shape index. These quantities can be successively estimated on the basis of simplified equations which are expressed in terms of the egg length, L¸ and its width, B. The surface area of the eggshells also exhibits good correlation with the egg long circumference length. Some limitations of the most used procedures have been also shown.

  19. Null twisted geometries

    CERN Document Server

    Speziale, Simone

    2013-01-01

    We define and investigate a quantisation of null hypersurfaces in the context of loop quantum gravity on a fixed graph. The main tool we use is the parametrisation of the theory in terms of twistors, which has already proved useful in discussing the interpretation of spin networks as the quantization of twisted geometries. The classical formalism can be extended in a natural way to null hypersurfaces, with the Euclidean polyhedra replaced by null polyhedra with space-like faces, and SU(2) by the little group ISO(2). The main difference is that the simplicity constraints present in the formalims are all first class, and the symplectic reduction selects only the helicity subgroup of the little group. As a consequence, information on the shapes of the polyhedra is lost, and the result is a much simpler, abelian geometric picture. It can be described by an Euclidean singular structure on the 2-dimensional space-like surface defined by a foliation of space-time by null hypersurfaces. This geometric structure is na...

  20. Matrix Information Geometry

    CERN Document Server

    Bhatia, Rajendra

    2013-01-01

    This book is an outcome of the Indo-French Workshop on Matrix Information Geometries (MIG): Applications in Sensor and Cognitive Systems Engineering, which was held in Ecole Polytechnique and Thales Research and Technology Center, Palaiseau, France, in February 23-25, 2011. The workshop was generously funded by the Indo-French Centre for the Promotion of Advanced Research (IFCPAR).  During the event, 22 renowned invited french or indian speakers gave lectures on their areas of expertise within the field of matrix analysis or processing. From these talks, a total of 17 original contribution or state-of-the-art chapters have been assembled in this volume. All articles were thoroughly peer-reviewed and improved, according to the suggestions of the international referees. The 17 contributions presented  are organized in three parts: (1) State-of-the-art surveys & original matrix theory work, (2) Advanced matrix theory for radar processing, and (3) Matrix-based signal processing applications.  

  1. Positive geometries and canonical forms

    Science.gov (United States)

    Arkani-Hamed, Nima; Bai, Yuntao; Lam, Thomas

    2017-11-01

    Recent years have seen a surprising connection between the physics of scattering amplitudes and a class of mathematical objects — the positive Grassmannian, positive loop Grassmannians, tree and loop Amplituhedra — which have been loosely referred to as "positive geometries". The connection between the geometry and physics is provided by a unique differential form canonically determined by the property of having logarithmic singularities (only) on all the boundaries of the space, with residues on each boundary given by the canonical form on that boundary. The structures seen in the physical setting of the Amplituhedron are both rigid and rich enough to motivate an investigation of the notions of "positive geometries" and their associated "canonical forms" as objects of study in their own right, in a more general mathematical setting. In this paper we take the first steps in this direction. We begin by giving a precise definition of positive geometries and canonical forms, and introduce two general methods for finding forms for more complicated positive geometries from simpler ones — via "triangulation" on the one hand, and "push-forward" maps between geometries on the other. We present numerous examples of positive geometries in projective spaces, Grassmannians, and toric, cluster and flag varieties, both for the simplest "simplex-like" geometries and the richer "polytope-like" ones. We also illustrate a number of strategies for computing canonical forms for large classes of positive geometries, ranging from a direct determination exploiting knowledge of zeros and poles, to the use of the general triangulation and push-forward methods, to the representation of the form as volume integrals over dual geometries and contour integrals over auxiliary spaces. These methods yield interesting representations for the canonical forms of wide classes of positive geometries, ranging from the simplest Amplituhedra to new expressions for the volume of arbitrary convex

  2. What are the longevities of teeth and oral implants?

    DEFF Research Database (Denmark)

    Holm-Pedersen, Poul; Lang, Niklaus P; Müller, Frauke

    2007-01-01

    To analyse tooth loss and to evaluate the longevity of healthy teeth and teeth compromised by diseases and influenced by therapy as well as that of oral implants.......To analyse tooth loss and to evaluate the longevity of healthy teeth and teeth compromised by diseases and influenced by therapy as well as that of oral implants....

  3. Spatial geometry and special relativity

    DEFF Research Database (Denmark)

    Kneubil, Fabiana Botelho

    2016-01-01

    In this work, it is shown the interplay of relative and absolute entities, which are present in both spatial geometry and special relativity. In order to strengthen the understanding of special relativity, we discuss firstly an instance of geometry and the existence of both frame-dependent and fr...

  4. Geometry of the quantum universe

    NARCIS (Netherlands)

    Ambjørn, J.; Görlich, A.; Jurkiewicz, J.; Loll, R.

    2010-01-01

    A quantum universe with the global shape of a (Euclidean) de Sitter spacetime appears as dynamically generated background geometry in the causal dynamical triangulation (CDT) regularisation of quantum gravity. We investigate the micro- and macro-geometry of this universe, using geodesic shell

  5. GPS: Geometry, Probability, and Statistics

    Science.gov (United States)

    Field, Mike

    2012-01-01

    It might be said that for most occupations there is now less of a need for mathematics than there was say fifty years ago. But, the author argues, geometry, probability, and statistics constitute essential knowledge for everyone. Maybe not the geometry of Euclid, but certainly geometrical ways of thinking that might enable us to describe the world…

  6. Surrogate Modeling for Geometry Optimization

    DEFF Research Database (Denmark)

    Rojas Larrazabal, Marielba de la Caridad; Abraham, Yonas; Holzwarth, Natalie

    2009-01-01

    A new approach for optimizing the nuclear geometry of an atomic system is described. Instead of the original expensive objective function (energy functional), a small number of simpler surrogates is used.......A new approach for optimizing the nuclear geometry of an atomic system is described. Instead of the original expensive objective function (energy functional), a small number of simpler surrogates is used....

  7. Basic algebraic geometry, v.2

    CERN Document Server

    Shafarevich, Igor Rostislavovich

    1994-01-01

    Shafarevich Basic Algebraic Geometry 2 The second edition of Shafarevich's introduction to algebraic geometry is in two volumes. The second volume covers schemes and complex manifolds, generalisations in two different directions of the affine and projective varieties that form the material of the first volume. Two notable additions in this second edition are the section on moduli spaces and representable functors, motivated by a discussion of the Hilbert scheme, and the section on Kähler geometry. The book ends with a historical sketch discussing the origins of algebraic geometry. From the Zentralblatt review of this volume: "... one can only respectfully repeat what has been said about the first part of the book (...): a great textbook, written by one of the leading algebraic geometers and teachers himself, has been reworked and updated. As a result the author's standard textbook on algebraic geometry has become even more important and valuable. Students, teachers, and active researchers using methods of al...

  8. Forensic identification in teeth with caries.

    Science.gov (United States)

    Alia-García, Esther; Parra-Pecharromán, David; Sánchez-Díaz, Ana; Mendez, Susy; Royuela, Ana; Gil-Alberdi, Laura; López-Palafox, Juan; del Campo, Rosa

    2015-12-01

    Human teeth are biological structures that resist extreme conditions thus becoming a useful source of DNA for human forensic identification purposes. When it is possible, forensic prefer only non-damaged teeth whereas those with cavities are usually rejected to avoid both external and internal bacterial contamination. Cavities are one of the most prevalent dental pathology and its incidence increases with ageing. The aim of this study was to validate the use of teeth with cavities for forensic identification. A total of 120 individual teeth from unrelated patients (60 healthy and 60 with cavities, respectively) extracted by a dentist as part of the normal process of treatment, were submitted for further analysis. Dental pulp was obtained after tooth fragmentation, complete DNA was extracted and the corresponding human identification profile was obtained by the AmpFlSTR® NGM SElect™ kit. Cariogenic microbiota was determined by PCR-DGGE with bacterial universal primers and bands were excised, re-amplified and sequenced. From the 120 dental pieces analyzed, a defined genetic profile was obtained in 81 (67.5%) of them, with no statistical differences between the healthy and the cavities-affected teeth. Statistical association between teeth status, DNA content and genetic profiles was not observed. Complex bacterial communities were only detected in the cavities group, being the Streptococcus/Enterococcus, and Lactobacillus genera the most represented. We conclude that teeth with cavities are as valid as healthy dental pieces for forensic human identification. Moreover, the severity of the cariogenic lesion as well as associated bacterial communities seems not to influence the establishment of human dental profiles. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  9. Missing teeth and pediatric obstructive sleep apnea.

    Science.gov (United States)

    Guilleminault, Christian; Abad, Vivien C; Chiu, Hsiao-Yean; Peters, Brandon; Quo, Stacey

    2016-05-01

    Missing teeth in early childhood can result in abnormal facial morphology with narrow upper airway. The potential association between dental agenesis or early dental extractions and the presence of obstructive sleep apnea (OSA) was investigated. We reviewed clinical data, results of polysomnographic sleep studies, and orthodontic imaging studies of children with dental agenesis (n = 32) or early extraction of permanent teeth (n = 11) seen during the past 5 years and compared their findings to those of age-, gender-, and body mass index-matched children with normal teeth development but tonsilloadenoid (T&A) hypertrophy and symptoms of OSA (n = 64). The 31 children with dental agenesis and 11 children with early dental extractions had at least 2 permanent teeth missing. All children with missing teeth (n = 43) had clinical complaints and signs evoking OSA. There was a significant difference in mean apnea-hypopnea indices (AHI) in the three dental agenesis, dental extraction, and T&A studied groups (p sleep, and presented with OSA recognized at a later age. Due to the low-grade initial symptomatology, sleep-disordered breathing may be left untreated for a prolonged period with progressive worsening of symptoms over time.

  10. Solid modeling of fossil small mammal teeth

    Science.gov (United States)

    Marschallinger, Robert; Hofmann, Peter; Daxner-Höck, Gudrun; Ketcham, Richard A.

    2011-09-01

    This paper presents an approach to create solid models of fossil small mammal teeth using a combination of microcomputed tomography, object based image analysis and voxel modeling. Small mammal teeth, because of their durability, are widely found in Cenozioc sediments the world over and play a key role in stratigraphy as well as in researching the rapid evolution and the paleogeographic spreading of small mammals. Recent advances in microcomputed tomography make this non-destructive analysis method an ideal data source for high-resolution 3D models of fossil small animal teeth. To derive internally consistent solid models of such fossils from micro-CT imagery, we propose a combination of 3D object based image analysis and solid modeling. Incorporating paleontological expert knowledge in the image processing cycle, object based image analysis yields topologically consistent image stacks classified by the main tooth components—enamel, dentine and pulp. Forwarding these data to a voxel modeling system, they can be quantitatively analyzed in an unprecedented manner: going beyond the possibilities of the state-of-art surface models, solid models are capable of unambiguously portraying the entire object volume—teeth can be peeled by material properties, subvolumes can be extracted and automatically analyzed by Boolean operations. The proposed method, which can be flexibly extended to handle a range of paleontological and geological micro-objects, is demonstrated with two typical fossil small mammal teeth.

  11. Quantum Geometry in the Lab

    Energy Technology Data Exchange (ETDEWEB)

    Hogan, Craig

    2013-03-24

    Standard particle theory is based on quantized matter embedded in a classical geometry. Here, a complementary model is proposed, based on classical matter -- massive bodies, without quantum properties -- embedded in a quantum geometry. It does not describe elementary particles, but may be a better, fully consistent quantum description for position states in laboratory-scale systems. Gravitational theory suggests that the geometrical quantum system has an information density of about one qubit per Planck length squared. If so, the model here predicts that the quantum uncertainty of geometry creates a new form of noise in the position of massive bodies, detectable by interferometers.

  12. A first course in geometry

    CERN Document Server

    Walsh, Edward T

    2014-01-01

    This introductory text is designed to help undergraduate students develop a solid foundation in geometry. Early chapters progress slowly, cultivating the necessary understanding and self-confidence for the more rapid development that follows. The extensive treatment can be easily adapted to accommodate shorter courses. Starting with the language of mathematics as expressed in the algebra of logic and sets, the text covers geometric sets of points, separation and angles, triangles, parallel lines, similarity, polygons and area, circles, space geometry, and coordinate geometry. Each chapter incl

  13. Differential geometry curves, surfaces, manifolds

    CERN Document Server

    Kühnel, Wolfgang

    2015-01-01

    This carefully written book is an introduction to the beautiful ideas and results of differential geometry. The first half covers the geometry of curves and surfaces, which provide much of the motivation and intuition for the general theory. The second part studies the geometry of general manifolds, with particular emphasis on connections and curvature. The text is illustrated with many figures and examples. The prerequisites are undergraduate analysis and linear algebra. This new edition provides many advancements, including more figures and exercises, and-as a new feature-a good number of so

  14. Differential geometry and symmetric spaces

    CERN Document Server

    Helgason, Sigurdur

    2001-01-01

    Sigurdur Helgason's Differential Geometry and Symmetric Spaces was quickly recognized as a remarkable and important book. For many years, it was the standard text both for Riemannian geometry and for the analysis and geometry of symmetric spaces. Several generations of mathematicians relied on it for its clarity and careful attention to detail. Although much has happened in the field since the publication of this book, as demonstrated by Helgason's own three-volume expansion of the original work, this single volume is still an excellent overview of the subjects. For instance, even though there

  15. Head First 2D Geometry

    CERN Document Server

    Fallow), Stray

    2009-01-01

    Having trouble with geometry? Do Pi, The Pythagorean Theorem, and angle calculations just make your head spin? Relax. With Head First 2D Geometry, you'll master everything from triangles, quads and polygons to the time-saving secrets of similar and congruent angles -- and it'll be quick, painless, and fun. Through entertaining stories and practical examples from the world around you, this book takes you beyond boring problems. You'll actually use what you learn to make real-life decisions, like using angles and parallel lines to crack a mysterious CSI case. Put geometry to work for you, and

  16. An improved combinatorial geometry model for arbitrary geometry in DSMC

    Science.gov (United States)

    Kargaran, H.; Minuchehr, A.; Zolfaghari, A.

    2017-03-01

    This paper focuses on a new direct simulation Monte Carlo (DSMC) code based on combinatorial geometry (CG) for simulation of any rarefied gas flow. The developed code, called DgSMC-A, has been supplied with an improved CG modeling able to significantly optimize the particle-tracking process, resulting in a highly reduced runtime compared to the conventional codes. The improved algorithm inserts a grid over the geometry and saves those grid elements containing some part of the geometry border. Since only a small part of a grid is engaged with the geometry border, significant time can be saved using the proposed algorithm. Embedding the modified algorithm in the DgSMC-A resulted in a fast, robust and self-governing code needless to any mesh generator. The code completely handles complex geometries created with first-and second-order surfaces. In addition, we developed a new surface area calculator in the CG methodology for complex geometries based on the Monte Carlo method with acceptable accuracy. Several well-known test cases are examined to indicate the code ability to deal with a wide range of realistic problems. Results are also found to be in good agreement with references and experimental data.

  17. Supernumerary teeth vary depending on gender

    Directory of Open Access Journals (Sweden)

    Erika Calvano Küchler

    2011-02-01

    Full Text Available The presence of supernumerary teeth (ST is a dental developmental anomaly of patterning and morphogenesis. Its variability of morphology, location and developmental timing can shed light on its etiology. In this work we report ST patterns. Orthopantomograms of 1,166 pediatric subjects were examined and the morphology, location and timing of the formation of ST were determined. The frequency of supernumerary teeth in the studied population was 2.3% (n = 27. Twenty-five subjects presented one ST. Maxilla midline was the most commonly affected region (nine cases. We noted high incidence of conical morphology in the midline region. Only teeth with tuberculate morphology presented delayed formation. ST in the midline region occurred more often in males whereas ST in the incisor region were more common in females. In conclusion, ST patterns vary depending on gender.

  18. Rotary endodontics in primary teeth - A review.

    Science.gov (United States)

    George, Sageena; Anandaraj, S; Issac, Jyoti S; John, Sheen A; Harris, Anoop

    2016-01-01

    Endodontic treatment in primary teeth can be challenging and time consuming, especially during canal preparation, which is considered one of the most important steps in root canal therapy. The conventional instrumentation technique for primary teeth remains the "gold-standard" over hand instrumentation, which makes procedures much more time consuming and adversely affects both clinicians and patients. Recently nickel-titanium (Ni-Ti) rotary files have been developed for use in pediatric endodontics. Using rotary instruments for primary tooth pulpectomies is cost effective and results in fills that are consistently uniform and predictable. This article reviews the use of nickel-titanium rotary files as root canal instrumentation in primary teeth. The pulpectomy technique is described here according to different authors and the advantages and disadvantages of using rotary files are discussed.

  19. Bioengineered teeth from tooth bud cells.

    Science.gov (United States)

    Yelick, Pamela C; Vacanti, Joseph P

    2006-04-01

    Advances in tissue engineering and materials science have led to significant progress in hard and soft tissue repair and regeneration. Studies demonstrate the successful application of tissue engineering for bioengineering dental tissues. The ability to apply tissue engineering to repair or regenerate dental tissues and even whole teeth is becoming a reality. Current efforts focus on directing the formation of bioengineered dental tissues and whole teeth of predetermined size and shape. Advances in dental progenitor cell characterizations, combined with improved methods of fabricating biodegradable scaffold materials, bring closer the goal of making tooth tissue engineering a clinically relevant practice.

  20. Radiographic analysis of traumatized primary teeth

    OpenAIRE

    Torriani, Dione Dias; Baldisseira, Elaine de Fatima Zanchin; Moura, Sílvia Aparecida Ximenes; Ferro, Renata da Luz; Goettems, Marília Leão

    2016-01-01

    This study aimed to evaluate the frequency of radiographic findings in primary teeth, as well as their supporting tissues, following dental trauma, and the occurrence of sequelae according to the trauma type.One radiograph was taken soon after the trauma, and two follow-up radiographs, with approximately sixmonth intervals between each, were taken of 116 traumatized teeth from 65 patients at the Pelotas DentistrySchool in Pelotas, Santa Catarina, Brazil. One hundred and ninety-five radiograph...

  1. Hyperbolic Metamaterials with Complex Geometry

    DEFF Research Database (Denmark)

    Lavrinenko, Andrei; Andryieuski, Andrei; Zhukovsky, Sergei

    2016-01-01

    We investigate new geometries of hyperbolic metamaterialssuch as highly corrugated structures, nanoparticle monolayer assemblies, super-structured or vertically arranged multilayersand nanopillars. All structures retain basic propertiesof hyperbolic metamaterials, but have functionality improved...

  2. Advances in discrete differential geometry

    CERN Document Server

    2016-01-01

    This is one of the first books on a newly emerging field of discrete differential geometry and an excellent way to access this exciting area. It surveys the fascinating connections between discrete models in differential geometry and complex analysis, integrable systems and applications in computer graphics. The authors take a closer look at discrete models in differential geometry and dynamical systems. Their curves are polygonal, surfaces are made from triangles and quadrilaterals, and time is discrete. Nevertheless, the difference between the corresponding smooth curves, surfaces and classical dynamical systems with continuous time can hardly be seen. This is the paradigm of structure-preserving discretizations. Current advances in this field are stimulated to a large extent by its relevance for computer graphics and mathematical physics. This book is written by specialists working together on a common research project. It is about differential geometry and dynamical systems, smooth and discrete theories, ...

  3. An introduction to differential geometry

    CERN Document Server

    Willmore, T J

    2012-01-01

    This text employs vector methods to explore the classical theory of curves and surfaces. Topics include basic theory of tensor algebra, tensor calculus, calculus of differential forms, and elements of Riemannian geometry. 1959 edition.

  4. Teeth loss, teeth brushing and esophageal carcinoma: a systematic review and meta-analysis.

    Science.gov (United States)

    Chen, Hui; Nie, Shuping; Zhu, Yuhui; Lu, Ming

    2015-10-14

    Esophageal carcinoma (EC) is a serious malignancy, and its epidemiologic etiology is not fully explained. We performed this review to investigate the association between teeth loss and teeth brushing and the risk of EC. A systematic search was conducted to identify all relevant studies. The Q test and I(2) statistic were used to examine between-study heterogeneity. Pooled odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were considered by fixed or random effects models. Furthermore, we conducted subgroup analyses based on study design, the studies' geographic regions and case type of origin. Modified Egger linear regression test was used to estimate publication bias. Ten articles were included. Pooled analyses indicated that teeth loss was associated with an increased risk of EC for Asians (OR, 1.52; 95% CI: 1.30, 1.78), and high frequency of teeth brushing was associated with a lower incidence of EC (OR, 0.62; 95%CI: 0.43, 0.89). Subgroup analyses showed consistent results and no publication bias existed. Teeth loss and teeth brushing play potential roles in the progressing of EC. People should take care of their oral health in daily life. And large well-designed researches are needed to fully describe the association between teeth health and EC risk.

  5. Higgs mass in noncommutative geometry

    Energy Technology Data Exchange (ETDEWEB)

    Devastato, A.; Martinetti, P. [Dipartimento di Fisica, Universita di Napoli Federico II, Via Cintia, 80126 Napoli (Italy); INFN, Sezione di Napoli, Via Cintia, 80126 Napoli (Italy); Lizzi, F. [Dipartimento di Fisica, Universita di Napoli Federico II, Via Cintia, 80126 Napoli (Italy); INFN, Sezione di Napoli, Via Cintia, 80126 Napoli (Italy); Departament de Estructura i Constituents de la Materia, Universitat de Barcelona, Marti y Franques, Barcelona, Catalonia (Spain)

    2014-09-11

    In the noncommutative geometry approach to the standard model, an extra scalar field σ - initially suggested by particle physicist to stabilize the electroweak vacuum - makes the computation of the Higgs mass compatible with the 126 GeV experimental value. We give a brief account on how to generate this field from the Majorana mass of the neutrino, following the principles of noncommutative geometry. (Copyright copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. The Common Geometry Module (CGM).

    Energy Technology Data Exchange (ETDEWEB)

    Tautges, Timothy James

    2004-12-01

    The Common Geometry Module (CGM) is a code library which provides geometry functionality used for mesh generation and other applications. This functionality includes that commonly found in solid modeling engines, like geometry creation, query and modification; CGM also includes capabilities not commonly found in solid modeling engines, like geometry decomposition tools and support for shared material interfaces. CGM is built upon the ACIS solid modeling engine, but also includes geometry capability developed beside and on top of ACIS. CGM can be used as-is to provide geometry functionality for codes needing this capability. However, CGM can also be extended using derived classes in C++, allowing the geometric model to serve as the basis for other applications, for example mesh generation. CGM is supported on Sun Solaris, SGI, HP, IBM, DEC, Linux and Windows NT platforms. CGM also includes support for loading ACIS models on parallel computers, using MPI-based communication. Future plans for CGM are to port it to different solid modeling engines, including Pro/Engineer or SolidWorks. CGM is being released into the public domain under an LGPL license; the ACIS-based engine is available to ACIS licensees on request.

  7. Finite Geometries: a tool for better understanding of Euclidean Geometry

    Directory of Open Access Journals (Sweden)

    Antonio Maturo

    2014-06-01

    Full Text Available An effective tool to really understand Euclidean geometry is the study of alternative models and their applications. In fact, they allow you to understand the real extent of various axioms that, when viewed from the Euclidean geometry, seem obvious or even unnecessary. The work begins with a review of Hilbert's axiomatic, starting from more general point of view adopted by Albrecht Beutelspacher and Ute Rosenbaum in their book on the fundamentals of general projective geometry (1998, defined by a system of incidence axioms.   Le Geometrie Finite: uno strumento per una migliore comprensione della Geometria Euclidea Uno strumento efficace per comprendere realmente la geometria euclidea è lo studio di modelli alternativi e delle loro applicazioni. Infatti essi permettono di capire la reale portata di vari assiomi che visti dall’interno della geometria euclidea sembrerebbero scontati o addirittura inutili. Il lavoro parte da una rivisitazione dell’assiomatica di Hilbert a partire dal punto di vista più generale adottato da Albrecht Beutelspacher e Ute Rosenbaum nel loro libro del 1998 sui fondamenti della geometria proiettiva generale, definita attraverso un sistema di assiomi di incidenza.  Parole Chiave: Critica dei fondamenti; Geometrie finite; Assiomi di Hilbert; Applicazioni.

  8. Teething & Dental Hygiene for Young Children

    Science.gov (United States)

    ... him so that the brush removes all the plaque—the soft, sticky, bacteria- containing deposits that accumulate on the teeth, causing tooth decay. Also, keep an eye out for areas of brown or white spots which might be signs of early decay. Toothbrushing As soon as your child has a tooth ...

  9. Differential expressions of bilaterally unerupted supernumerary teeth.

    Science.gov (United States)

    Masih, S; Sethi, H S; Singh, N; Thomas, A M

    2011-01-01

    This article presents a case of bilateral unerupted supernumerary teeth in the mandibular premolar region. Surgical removal of the right-sided supernumerary tooth had to be carried out as it was impeding the eruption of the mandibular first premolar. However, its supernumerary antimere, lay dormant.

  10. Simulation of a flow around biting teeth

    Science.gov (United States)

    Narusawa, Hideaki; Yamamoto, Eriko; Kuwahara, Kunio

    2008-11-01

    We simulated a flow around biting teeth. The decayed tooth is a disease that a majority of people are annoyed. These are often generated from a deep groove at occlusal surface. It is known that a person who bites well doesn't suffer from a decayed tooth easily. Biting forces reach as much as 60 kg/cm^2 by an adult male, and when chewing, upper and lower teeth approach to bite by those forces. The crushed food mixed with saliva becomes high viscosity fluid, and is pushed out of ditches of teeth in the direction of the cheek or the tongue. Teeth with complex three dimension curved surface are thought to form venturi at this time, and to generate big pressure partially. An excellent dental articulation will possibly help a natural generation of a flow to remove dental plaque, i.e. the cause of the decayed tooth. Moreover, the relation of this flow with the destruction of the filled metal or the polymer is doubted. In this research, we try to clarify the pressure distributions by this flow generation as well as its dynamics when chewing. One of our goals is to enable an objective design of the shape of the dental fillings and the artificial tooth. Tooth has a very small uneven ground and a bluff body. In this case, to calculate a computational numerical simulation to solve the Navier-Stokes equations three dimension Cartesian coordinate system is employed.

  11. Outcome of Endodontically Treated Cracked Teeth

    Science.gov (United States)

    2016-06-01

    Reversible pulpitis _Symptomatic irreversible pulpitis _Asymptomatic irreversible pulpitis _Pulp necrosis _Previously treated _Previously initiated...treatment Diagnosis Pulpal: __ Normal pulp __ Reversible pulpitis __ Asymptomatic irreversible pulpitis __ Symptomatic irreversible pulp!Us...the course of the study. Opdam et al. (2008) followed 40 patients diagnosed with cracked teeth and reversible pulpitis . These patients received either

  12. Restoration of Endodontically-Treated Anterior Teeth.

    Science.gov (United States)

    Shelley, Andrew

    2017-02-28

    Detailed consideration of a case involving the restoration of an endodontically-treated maxillary canine tooth provides opportunity to review the many different considerations and treatment options in such situations. The restoration of endodontically-treated anterior teeth must be patient-centred, applying materials and techniques best suited to achieve a successful clinical outcome.

  13. Teeth: Among Nature's Most Durable Biocomposites

    Science.gov (United States)

    Lawn, Brian R.; Lee, James J.-W.; Chai, Herzl

    2010-08-01

    This paper addresses the durability of natural teeth from a materials perspective. Teeth are depicted as smart biocomposites, highly resistant to cumulative deformation and fracture. Favorable morphological features of teeth at both macroscopic and microscopic levels contribute to an innate damage tolerance. Damage modes are activated readily within the brittle enamel coat but are contained from spreading catastrophically into the vulnerable tooth interior in sustained occlusal loading. Although tooth enamel contains a multitude of microstructural defects that can act as sources of fracture, substantial overloads are required to drive any developing cracks to ultimate failure—nature's strategy is to contain damage rather than avoid it. Tests on model glass-shell systems simulating the basic elements of the tooth enamel/dentin layer structure help to identify important damage modes. Fracture and deformation mechanics provide a basis for analyzing critical conditions for each mode, in terms of characteristic tooth dimensions and materials properties. Comparative tests on extracted human and animal teeth confirm the validity of the model test approach and point to new research directions. Implications in biomechanics, especially as they relate to dentistry and anthropology, are outlined.

  14. Sterilisation of extracted human teeth for educational use

    Directory of Open Access Journals (Sweden)

    Kumar M

    2005-01-01

    Full Text Available Sixty intact, non-carious and unrestored teeth extracted due to periodontal disease were used to determine the most effective method of sterilisation. The teeth were divided into six groups, each containing 10 teeth. Group 1 teeth were immersed in 10% formalin for seven days, group 2 teeth were immersed in 3% hydrogen peroxide for seven days, group 3 teeth were immersed in 2.6% sodium hypochlorite for seven days, group 4 teeth were boiled in water at 100°C for 20 minutes, group 5 teeth were autoclaved at 121°C at 15 lbs psi for 30 minutes, and group 6 teeth were immersed in normal saline for seven days. After the treatment, the teeth were individually inoculated into trypticase soy broth and incubated for 48 hours. A questionnaire survey was also conducted to determine the awareness of dental students regarding infection due to extracted human teeth and the common disinfection/sterilisation methods used. Autoclaving at 121°C, 15 lbs psi for 30 minutes and immersion in 10% formalin for seven days were effective in disinfecting/sterilising extracted human teeth. Chemicals such as 2.6% sodium hypochlorite, 3% hydrogen peroxide and boiling in water were not effective. The results indicate that autoclaving for 30 minutes or immersion in 10% formalin for seven days could be effectively used for disinfection/sterilisation of extracted human teeth.

  15. Three-dimensional simulation of human teeth and its application in dental education and research.

    Science.gov (United States)

    Koopaie, Maryam; Kolahdouz, Sajad

    2016-01-01

    Background: A comprehensive database, comprising geometry and properties of human teeth, is needed for dentistry education and dental research. The aim of this study was to create a three-dimensional model of human teeth to improve the dental E-learning and dental research. Methods: In this study, a cross-section picture of the three-dimensional model of the teeth was used. CT-Scan images were used in the first method. The space between the cross- sectional images was about 200 to 500 micrometers. Hard tissue margin was detected in each image by Matlab (R2009b), as image processing software. The images were transferred to Solidworks 2015 software. Tooth border curve was fitted on B-spline curves, using the least square-curve fitting algorithm. After transferring all curves for each tooth to Solidworks, the surface was created based on the surface fitting technique. This surface was meshed in Meshlab-v132 software, and the optimization of the surface was done based on the remeshing technique. The mechanical properties of the teeth were applied to the dental model. Results: This study presented a methodology for communication between CT-Scan images and the finite element and training software through which modeling and simulation of the teeth were performed. In this study, cross-sectional images were used for modeling. According to the findings, the cost and time were reduced compared to other studies. Conclusion: The three-dimensional model method presented in this study facilitated the learning of the dental students and dentists. Based on the three-dimensional model proposed in this study, designing and manufacturing the implants and dental prosthesis are possible.

  16. Baby Teeth Link Autism and Heavy Metals, NIH Study Suggests

    Science.gov (United States)

    ... Release Thursday, June 1, 2017 Baby teeth link autism and heavy metals, NIH study suggests Cross-section ... Sinai Health System Baby teeth from children with autism contain more toxic lead and less of the ...

  17. [The registration of false teeth and the others].

    Science.gov (United States)

    Huang, Yi-wu

    2006-07-01

    The quality control of false teeth should include the control for designing and processing. The registration of false teeth should emphasize particularly on the qualification of the makers, technology management, quality control and the labeling.

  18. Teeth loss, teeth brushing and esophageal carcinoma: a systematic review and meta-analysis

    OpenAIRE

    Chen, Hui; Nie, Shuping; Zhu, Yuhui; Lu, Ming

    2015-01-01

    Esophageal carcinoma (EC) is a serious malignancy, and its epidemiologic etiology is not fully explained. We performed this review to investigate the association between teeth loss and teeth brushing and the risk of EC. A systematic search was conducted to identify all relevant studies. The Q test and I 2 statistic were used to examine between-study heterogeneity. Pooled odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were considered by fixed or random effects models. Furt...

  19. Teeth whitening versus the influence of extrinsic factors on teeth stains.

    Science.gov (United States)

    Nakonieczna-Rudnicka, Marta; Bachanek, Teresa; Madejczyki, Marlena; Grajewskai, Iwona; Kobyłecka, Elzbieta

    2015-01-01

    The improvement of teeth colour is the effect of using whitening toothpastes, professional removal of dental deposits, pulpless teeth and vital teeth whitening. The aim of the study was evaluation of various methods of teeth whitening in relation to sex and age of the investigated as well as the extrinsic factors causing teeth stains such as cigarette smoking, consumption of coffee and tea. Questionnaire survey was conducted in the group of 204 patients, reporting for a dental treatment at the Chair and Department of Conservative Dentistry with Endodontics of the Medical University of Lublin as well as private dental practice in Lublin. Questionnaire survey was elaborated for the needs of the planned investigation and included questions concerning, among others, socio-demographic data of the investigated, methods of teeth whitening, cigarette smoking, consumption of coffee and tea. Statistic analysis was performed with the use of descriptive statistics, Chi2 test, Mann-Whitney test. The values of p whitening toothpastes more frequently in comparison with men (χ2 = 7.96, p whitening toothpastes more frequently in comparison with the people drinking coffee occasionally and those who didn't drink it (χ2 = 9.99, p < χ0.05).

  20. A survey of natal and neonatal teeth in newborn infants

    OpenAIRE

    Chun-Hsiang Wang; Yai-Tin Lin; Yng-Tzer J. Lin

    2017-01-01

    Since there is no comprehensive research of natal and neonatal teeth in Taiwan, careful investigation of natal or neonatal teeth is worthy of being studied. This retrospective study investigated the prevalence and clinical characteristics of natal or neonatal teeth in a hospital setting, and analyzed the possible relationships between investigated variables of the natal or neonatal teeth. Methods: All of the 12,019 infants born at an assigned hospital between January 1, 2008 and December 3...

  1. Prevalence, etiology, diagnosis, treatment and complications of supernumerary teeth

    OpenAIRE

    Ata-Ali Mahmud, Fadi; Ata-Ali Mahmud, Francisco Javier; Peñarrocha Oltra, David; Peñarrocha Diago, Miguel

    2014-01-01

    The aim of this article was to review the literature on supernumerary teeth, analyzing their prevalence, etiology, diagnosis, treatment and possible complications. An electronic search was made in the Pubmed-Medline database up to January 2014 using the key search terms ?multiple supernumerary teeth? (n=279), ?prevalence supernumerary teeth? (n=361), and ?supernumerary teeth? (n=2412). In addition to the articles initially identified, others were included in the review proceeding from a manua...

  2. Reduction of contact stresses using involute gears with asymmetric teeth

    Directory of Open Access Journals (Sweden)

    Jarmila VOJTKOVÁ

    2015-12-01

    Full Text Available Asymmetrical involute gears have a different value of the operating pressure angle for right and left side of the gear. These teeth are suitable for one direction of rotation. Such teeth enable to change the length of the generating line. They enable to improve the value of reduced radii of curvature. Asymmetrical teeth allow reducing the values of Hertz's pressures, especially on the root of the teeth. Hertz pressures are directly related to the asymmetry.

  3. Bilateral radicular cysts of mandibular deciduous teeth: a case report.

    Science.gov (United States)

    Gaynor, Wanda N

    2012-09-01

    While common in adult teeth, radicular cysts are uncommon in deciduous teeth. When they do occur, they are associated with non-vital teeth and typically present 6 months to 5 years after vitality is lost. They cause swelling, bone-loss and permanent tooth bud displacement. Often, they are incidental findings. A case involving radicular cysts on the left and right sides of the mandible is presented. If non-vital deciduous teeth receive pulp therapy, regular post- operative reviews are recommended.

  4. Quantum geometry and gravitational entropy

    Energy Technology Data Exchange (ETDEWEB)

    Simon, Joan; Balasubramanian, Vijay; Czech, Bart Iomiej; Larjo, Klaus; Marolf, Donald; Simon, Joan

    2007-05-29

    Most quantum states have wavefunctions that are widely spread over the accessible Hilbert space and hence do not have a good description in terms of a single classical geometry. In order to understand when geometric descriptions are possible, we exploit the AdS/CFT correspondence in the half-BPS sector of asymptotically AdS_5 x S5 universes. In this sector we devise a"coarse-grained metric operator" whose eigenstates are well described by a single spacetime topology and geometry. We show that such half-BPS universes have a non-vanishing entropy if and only if the metric is singular, and that the entropy arises from coarse-graining the geometry. Finally, we use our entropy formula to find the most entropic spacetimes with fixed asymptotic moments beyond the global charges.

  5. Euclidean geometry and its subgeometries

    CERN Document Server

    Specht, Edward John; Calkins, Keith G; Rhoads, Donald H

    2015-01-01

    In this monograph, the authors present a modern development of Euclidean geometry from independent axioms, using up-to-date language and providing detailed proofs. The axioms for incidence, betweenness, and plane separation are close to those of Hilbert. This is the only axiomatic treatment of Euclidean geometry that uses axioms not involving metric notions and that explores congruence and isometries by means of reflection mappings. The authors present thirteen axioms in sequence, proving as many theorems as possible at each stage and, in the process, building up subgeometries, most notably the Pasch and neutral geometries. Standard topics such as the congruence theorems for triangles, embedding the real numbers in a line, and coordinatization of the plane are included, as well as theorems of Pythagoras, Desargues, Pappas, Menelaus, and Ceva. The final chapter covers consistency and independence of axioms, as well as independence of definition properties. There are over 300 exercises; solutions to many of the...

  6. Guide to Computational Geometry Processing

    DEFF Research Database (Denmark)

    Bærentzen, Jakob Andreas; Gravesen, Jens; Anton, François

    be processed before it is useful. This Guide to Computational Geometry Processing reviews the algorithms for processing geometric data, with a practical focus on important techniques not covered by traditional courses on computer vision and computer graphics. This is balanced with an introduction...... to the theoretical and mathematical underpinnings of each technique, enabling the reader to not only implement a given method, but also to understand the ideas behind it, its limitations and its advantages. Topics and features: Presents an overview of the underlying mathematical theory, covering vector spaces......, metric space, affine spaces, differential geometry, and finite difference methods for derivatives and differential equations Reviews geometry representations, including polygonal meshes, splines, and subdivision surfaces Examines techniques for computing curvature from polygonal meshes Describes...

  7. Variable geometry Darrieus wind machine

    Science.gov (United States)

    Pytlinski, J. T.; Serrano, D.

    1983-08-01

    A variable geometry Darrieus wind machine is proposed. The lower attachment of the blades to the rotor can move freely up and down the axle allowing the blades of change shape during rotation. Experimental data for a 17 m. diameter Darrieus rotor and a theoretical model for multiple streamtube performance prediction were used to develop a computer simulation program for studying parameters that affect the machine's performance. This new variable geometry concept is described and interrelated with multiple streamtube theory through aerodynamic parameters. The computer simulation study shows that governor behavior of a Darrieus turbine can not be attained by a standard turbine operating within normally occurring rotational velocity limits. A second generation variable geometry Darrieus wind turbine which uses a telescopic blade is proposed as a potential improvement on the studied concept.

  8. Double Teeth in the Sperm Whale (Physeter macrocephalus L.)

    NARCIS (Netherlands)

    Boschma, H.

    1938-01-01

    Recently a fairly large number of teeth of the sperm whale were acquired for the collections of the Rijksmuseum van Natuurlijke Historic These teeth were picked out from an extensive material of sperm whale teeth collected in the Antarctic region and preserved by the whalers for their commercial

  9. A sixteen year sample of surgically treated supernumerary teeth.

    Science.gov (United States)

    Pippi, R

    2011-03-01

    Supernumerary teeth represent a numerical dental anomaly in which more teeth than the norm are present in the dentition. A sixteen year sample of supernumerary teeth has been reviewed in order to analyse epidemiological data, morphological and topographic features of these teeth, especially of those located in the praemaxillary region. All cases in which supernumerary teeth were surgically treated from 1991 to 2006 at the Oral Surgery Unit of the Sapienza University of Rome have been reviewed. 118 Caucasian subjects with supernumerary teeth have been reviewed in the range of age comprised between 5 and 42 years: 191 SNTs were collected, 136 from the upper jaw and 55 from the mandible. In the maxilla the incisor region was more frequently involved (67.65%), while in the mandible the one most frequently involved was the premolar region (69.1%). Conoid was the most frequent type of supernumerary teeth. Uneruption of the contiguous permanent teeth was the most commonly associated pathological condition, found in 81 out of the 191 cases of supernumerary teeth (40 patients, 42.4%). Tuberculated, infundibuliform and incisiform-shaped teeth caused uneruption of permanent teeth more frequently than the other morphological types of supernumerary teeth. In the upper incisor area, the extraction of SNT is mandatory as early as they are diagnosed, especially if they are tuberculated, infundibuliform and incisiform-shaped, if they are located palatally or just in the middle of the ridge and when more than one SNT is present.

  10. Prevalence, etiology, diagnosis, treatment and complications of supernumerary teeth.

    Science.gov (United States)

    Ata-Ali, Fadi; Ata-Ali, Javier; Peñarrocha-Oltra, David; Peñarrocha-Diago, Miguel

    2014-10-01

    The aim of this article was to review the literature on supernumerary teeth, analyzing their prevalence, etiology, diagnosis, treatment and possible complications. An electronic search was made in the Pubmed-Medline database up to January 2014 using the key search terms "multiple supernumerary teeth" (n=279), "prevalence supernumerary teeth" (n=361), and "supernumerary teeth" (n=2412). In addition to the articles initially identified, others were included in the review proceeding from a manual search and from any references considered of relevance. Supernumerary teeth are those that exceed the normal dental formula. They are more common in men, more common in the upper maxilla, and more prevalent in permanent dentition. Complications associated with supernumerary teeth include dental impaction, delayed eruption, ectopic eruption, overcrowding, spacing anomalies and the formation of follicular cysts. The treatment of supernumerary teeth depends on their type, position, and possible complications, detected clinically and radiographically. No clear consensus exists as to the best time to extract unerupted supernumerary teeth. Key words:Hyperdoncia, supernumerary teeth, impacted teeth, treatment, permanent teeth, deciduous teeth.

  11. Teeth and tongue discoloration after linezolid treatment in children.

    Science.gov (United States)

    Petropoulou, Theoni; Lagona, Evagelia; Syriopoulou, Vassiliki; Michos, Athanasios

    2013-11-01

    We describe 3 children who developed teeth and tongue discoloration while receiving intravenous linezolid for 2 to 3 weeks. Linezolid was coadministered with piperacillin-tazobactam or meropenem. Teeth and tongue discoloration was reversible with dental cleaning after discontinuation of linezolid. We review the published pediatric and adult cases regarding teeth and tongue discoloration after linezolid administration.

  12. Natal teeth in an infant with congenital hypothyroidism

    Directory of Open Access Journals (Sweden)

    C Venkatesh

    2011-01-01

    Full Text Available Teeth erupting at birth are referred to as natal teeth. It is a common and benign finding in the neonatal period. However, they may be associated with genetic syndromes like Ellis Van Creveld syndrome and Hallermann-Streiff syndrome. We report here a case of natal teeth in an infant with congenital hypothyroidism.

  13. Characteristics of supernumerary teeth among nonsyndromic dental patients

    Directory of Open Access Journals (Sweden)

    Szu-Ting Chou

    2015-06-01

    Conclusion: The prevalence of supernumerary teeth in this study was 2.6%, the most frequent location being at the anterior maxilla. Numerous factors should be considered when evaluating supernumerary teeth. Specifically, the demographic profiles of patients with supernumerary teeth provide useful epidemiological information.

  14. Fracture resistance of tooth restored with four glass fiber post systems of varying surface geometries-An in vitro study.

    Science.gov (United States)

    Jayasenthil, Adhikesavan; Solomon-Sathish, Emmanuel; Venkatalakshmi-Aparna, Potluri; Balagopal, Sunderasan

    2016-02-01

    The purpose of this study was to relate the fracture resistance of endodontically treated teeth in relation to post geometry. Forty single rooted mandibular premolars were instrumented by step - back technique and obturated by lateral condensation. Forty teeth were randomly divided into four groups: Reforpost glass fiber X-ray®, RelyX®, Exacto conical® and Parapost Fiber Lux®. The post spaces were prepared using respective drills and luted. The core build up was done and metal crowns were luted. Fracture resistance was determined in universal testing machine. The statistical analysis was done using one way ANOVA and post hoc Tukey Kramer test. The teeth restored with Reforpost showed highest fracture resistance followed by Parapost and Exacto conical. The teeth restored with RelyX showed least fracture resistance. The teeth restored with Parapost had less unfavourable fracture followed by exacto conical. Parallel design had less number of catastrophic failure and had better fracture resistance. Fracture resistance, glass fiber post, post geometry, stress.

  15. KEMAJUAN BELAJAR SISWA PADA GEOMETRI TRANSFORMASI MENGGUNAKAN AKTIVITAS REFLEKSI GEOMETRI

    Directory of Open Access Journals (Sweden)

    Irkham Ulil Albab

    2014-10-01

    Full Text Available Abstrak: Penelitian ini bertujuan untuk mendeskripsikan kemajuan belajar siswa pada materi geometri transformasi yang didukung dengan serangkaian aktivitas belajar berdasarkan Pendidikan Matematika Realistik Indonesia. Penelitian didesain melalui tiga tahap, yaitu tahapan perancangan desain awal, pengujian desain melalui pembelajaran awal dan pembelajaran eksperimental, dan tahap analisis retrospektif. Dalam penelitian ini, Hypothetical Learning Trajectory, HLT (HLT berperan penting sebagai desain pembelajaran sekaligus instrumen penelitian. HLT diujikan terhadap 26 siswa kelas VII. Data dikumpulkan dengan teknik wawancara, pengamatan, dan catatan lapangan. Hasil penelitian menunjukkan bahwa desain pembelajaran ini mampu menstimulasi siswa untuk memberikan karakteristik refleksi dan transformasi geometri lainnya secara informal, mengklasifikasikannya dalam transformasi isometri pada level kedua, dan menemukan garis bantuan refleksi pada level yang lebih formal. Selain itu, garis bantuan refleksi digunakan oleh siswa untuk menggambar bayangan refleksi dan pola pencerminan serta memahami bentuk rotasi dan translasi sebagai kombinasi refleksi adalah level tertinggi. Keyword: transformasi geometri, kombinasi refleksi, rotasi, translasi, design research, HLT STUDENTS’ LEARNING PROGRESS ON TRANSFORMATION GEOMETRY USING THE GEOMETRY REFLECTION ACTIVITIES Abstract: This study was aimed at describing the students’ learning progress on transformation geometry supported by a set of learning activities based on Indonesian Realistic Mathematics Education. The study was designed into three stages, that is, the preliminary design stage, the design testing through initial instruction and experiment, and the restrospective analysis stage. In this study, Hypothetical Learning Trajectory (HLT played an important role as an instructional design and a research instrument. HLT was tested to 26 seventh grade students. The data were collected through interviews

  16. Geometry, topology, and string theory

    Energy Technology Data Exchange (ETDEWEB)

    Varadarajan, Uday [Univ. of California, Berkeley, CA (United States)

    2003-01-01

    A variety of scenarios are considered which shed light upon the uses and limitations of classical geometric and topological notions in string theory. The primary focus is on situations in which D-brane or string probes of a given classical space-time see the geometry quite differently than one might naively expect. In particular, situations in which extra dimensions, non-commutative geometries as well as other non-local structures emerge are explored in detail. Further, a preliminary exploration of such issues in Lorentzian space-times with non-trivial causal structures within string theory is initiated.

  17. Stochastic geometry and its applications

    CERN Document Server

    Chiu, Sung Nok; Kendall, Wilfrid S; Mecke, Joseph

    2013-01-01

    An extensive update to a classic text Stochastic geometry and spatial statistics play a fundamental role in many modern branches of physics, materials sciences, engineering, biology and environmental sciences. They offer successful models for the description of random two- and three-dimensional micro and macro structures and statistical methods for their analysis. The previous edition of this book has served as the key reference in its field for over 18 years and is regarded as the best treatment of the subject of stochastic geometry, both as a subject with vital a

  18. Algebraic geometry and theta functions

    CERN Document Server

    Coble, Arthur B

    1929-01-01

    This book is the result of extending and deepening all questions from algebraic geometry that are connected to the central problem of this book: the determination of the tritangent planes of a space curve of order six and genus four, which the author treated in his Colloquium Lecture in 1928 at Amherst. The first two chapters recall fundamental ideas of algebraic geometry and theta functions in such fashion as will be most helpful in later applications. In order to clearly present the state of the central problem, the author first presents the better-known cases of genus two (Chapter III) and

  19. Introduction to topology and geometry

    CERN Document Server

    Stahl, Saul

    2014-01-01

    An easily accessible introduction to over three centuries of innovations in geometry Praise for the First Edition ". . . a welcome alternative to compartmentalized treatments bound to the old thinking. This clearly written, well-illustrated book supplies sufficient background to be self-contained." -CHOICE This fully revised new edition offers the most comprehensive coverage of modern geometry currently available at an introductory level. The book strikes a welcome balance between academic rigor and accessibility, providing a complete and cohesive picture of the science with an unparallele

  20. Combinatorial geometry in the plane

    CERN Document Server

    Hadwiger, Hugo; Klee, Victor

    2014-01-01

    Geared toward advanced undergraduates familiar with analysis and college geometry, this concise book discusses theorems on topics restricted to the plane such as convexity, coverings, and graphs. In addition to helping students cultivate rigorous thought, the text encourages the development of mathematical intuition and clarifies the nature of mathematical research.The two-part treatment begins with specific topics including integral distances, covering problems, point set geometry and convexity, simple paradoxes involving point sets, and pure combinatorics, among other subjects. The second pa

  1. Lectures on Algebraic Geometry I

    CERN Document Server

    Harder, Gunter

    2012-01-01

    This book and the following second volume is an introduction into modern algebraic geometry. In the first volume the methods of homological algebra, theory of sheaves, and sheaf cohomology are developed. These methods are indispensable for modern algebraic geometry, but they are also fundamental for other branches of mathematics and of great interest in their own. In the last chapter of volume I these concepts are applied to the theory of compact Riemann surfaces. In this chapter the author makes clear how influential the ideas of Abel, Riemann and Jacobi were and that many of the modern metho

  2. Teaching Activity-Based Taxicab Geometry

    Science.gov (United States)

    Ada, Tuba

    2013-01-01

    This study aimed on the process of teaching taxicab geometry, a non-Euclidean geometry that is easy to understand and similar to Euclidean geometry with its axiomatic structure. In this regard, several teaching activities were designed such as measuring taxicab distance, defining a taxicab circle, finding a geometric locus in taxicab geometry, and…

  3. Dental Trauma: An inside to Avulsion Teeth

    OpenAIRE

    Mendes PhD, Beatriz

    2015-01-01

    Several studies shows that a wide range from 3-16% of dentoalveolar traumatic injuries result in avulsion. The ideal treatment for avulsion would be the reimplantation of the tooth. Thus, it is recommended to replant the tooth as quickly as possible. However, immediate repositioning of teeth is not always possible, so the choice of a suitable storage medium for maintenance of Periodontal Ligament cell viability is of extreme importance for the success of replantation. At the present article a...

  4. [Injuries to the permanent teeth. Periodontal lesions].

    Science.gov (United States)

    Vinckier, F; Declerck, D; Verhaeghe, V; Vanassche, K

    1998-01-01

    Tooth luxations are relatively common. In case of concussion or subluxation the tooth is not displaced. The treatment will consist of relief of the tooth. Most frequent complications are pulp necrosis and obliteration of pulpal tissues. In case of extrusive luxation pulpal tissues and the periodontal ligament are injured. When tooth mobility is increased flexible splinting should be considered. Endodontic treatment is necessary after extrusive luxation of a tooth with completed root formation. Teeth with open apex often show pulpal obliteration after extensive luxation. Lateral luxation is more complex than extrusive luxation since the alveolar bone is also damaged. Repositioning and splinting of the tooth are necessary. When the apical foramen in closed, endodontic treatment will be necessary. Teeth with incomplete root formation will develop pulp obliteration. Following lateral luxation, external root resorption and loss of marginal bone are not infrequent. Intrusive luxation is the type of trauma with most unfavorable prognosis. All intruded teeth will become necrotic and external root resorption and marginal bone loss are frequent. There is no consensus regarding the therapeutic approach. Orthodontic extrusion or surgical mobilisation are possible options. In case of avulsion, both the pulpal tissues and the periodontal ligament are disrupted. Preservation of the vitality of the periodontal ligament covering the root will determine the prognosis of the reimplanted tooth. Therefore the tooth will be repositioned as soon as possible. When this is not possible, milk or a specific solution are most appropriate for tooth conservation. When the reimplanted tooth has complete root formation, devitalization will be performed one week after after repositioning. In case of a tooth with open apex revascularisation can be awaited. Healing of the periodontal ligament will determine prognosis. When a normal ligament is obtained during healing or when surface resorption is

  5. Pulpectomy procedures in primary molar teeth

    OpenAIRE

    Hany Mohamed Aly Ahmed

    2014-01-01

    Premature loss of primary molars can cause a number of undesirable consequences including loss of arch length, insufficient space for erupting premolars and mesial tipping of the permanent molars. Pulpectomy of primary molar teeth is considered as a reasonable treatment approach to ensure either normal shedding or a long-term survival in instances of retention. Despite being a more conservative treatment option than extraction, efficient pulpectomy of bizarre and tortuous root canals encased ...

  6. Understanding External Cervical Resorption in Vital Teeth.

    Science.gov (United States)

    Mavridou, Athina M; Hauben, Esther; Wevers, Martine; Schepers, Evert; Bergmans, Lars; Lambrechts, Paul

    2016-12-01

    The aim of this study was to investigate the 3-dimensional (3D) structure and the cellular and tissue characteristics of external cervical resorption (ECR) in vital teeth and to understand the phenomenon of ECR by combining histomorphological and radiographic findings. Twenty-seven cases of vital permanent teeth displaying ECR were investigated. ECR diagnosis was based on clinical and radiographic examination with cone-beam computed tomographic imaging. The extracted teeth were further analyzed by using nanofocus computed tomographic imaging, hard tissue histology, and scanning electron microscopy. All examined teeth showed some common characteristics. Based on the clinical and experimental findings, a 3-stage mechanism of ECR was proposed. At the first stage (ie, the initiation stage), ECR was initiated at the cementum below the gingival epithelial attachment. At the second stage (ie, the resorption stage), the resorption invaded the tooth structure 3-dimensionally toward the pulp space. However, it did not penetrate the pulp space because of the presence of a pericanalar resorption-resistant sheet. This layer was observed to consist of predentin, dentin, and occasionally reparative mineralized (bonelike) tissue, having a fluctuating thickness averaging 210 μm. At the last advanced stage (ie, the repair stage), repair took place by an ingrowth and apposition of bonelike tissue into the resorption cavity. During the reparative stage, repair and remodeling phenomena evolve simultaneously, whereas both resorption and reparative stages progress in parallel at different areas of the tooth. ECR is a dynamic and complex condition that involves periodontal and endodontic tissues. Using clinical, histologic, radiographic, and scanning microscopic analysis, a better understanding of the evolution of ECR is possible. Based on the experimental findings, a 3-stage mechanism for the initiation and growth of ECR is proposed. Copyright © 2016 American Association of

  7. Targeted traction of impacted teeth with C-tube miniplates.

    Science.gov (United States)

    Chung, Kyu-Rhim; Kim, Yong; Ahn, Hyo-Won; Lee, Dongjoo; Yang, Dong-Min; Kim, Seong-Hun; Nelson, Gerald

    2014-09-01

    Orthodontic traction of impacted teeth has typically been performed using full fixed appliance as anchorage against the traction force. This conventional approach can be difficult to apply in the mixed dentition if the partial fixed appliance offers an insufficient anchor unit. In addition, full fixed appliance can induce unwanted movement of adjacent teeth. This clinical report presents 3 cases where impacted teeth were recovered in the mixed or transitional dentition with skeletal anchorage on the opposite arch without full fixed appliance. Instead, intermaxillary traction was used to bring the impacted teeth into position. With this approach, side effects on teeth and periodontal tissues adjacent to the impaction were minimized.

  8. Normal forms in Poisson geometry

    NARCIS (Netherlands)

    Marcut, I.T.

    2013-01-01

    The structure of Poisson manifolds is highly nontrivial even locally. The first important result in this direction is Conn's linearization theorem around fixed points. One of the main results of this thesis (Theorem 2) is a normal form theorem in Poisson geometry, which is the Poisson-geometric

  9. Math Sense: Algebra and Geometry.

    Science.gov (United States)

    Howett, Jerry

    This book is designed to help students gain the range of math skills they need to succeed in life, work, and on standardized tests; overcome math anxiety; discover math as interesting and purposeful; and develop good number sense. Topics covered in this book include algebra and geometry. Lessons are organized around four strands: (1) skill lessons…

  10. College geometry a unified development

    CERN Document Server

    Kay, David C

    2011-01-01

    ""The book is a comprehensive textbook on basic geometry. … Key features of the book include numerous figures and many problems, more than half of which come with hints or even complete solutions. Frequent historical comments add to making the reading a pleasant one.""-Michael Joswig, Zentralblatt MATH 1273

  11. GEOMETRY AND COMPLEXITY IN ARCHITECTURE

    Directory of Open Access Journals (Sweden)

    RUSU Maria Ana

    2015-06-01

    Full Text Available As Constantin Brancuși (1876-1956 said „Simplicity is complexity itself“, simplicity and regularity through the use of basic geometric forms has always played a central role in architectural design, during the 20th century. A diachronic perspective, shows as the use of geometry and mathematics to describe built form provided a common basis for communication between the processes of design, fabrication and stability. Classic ways of representing geometry, based on descriptive methods, favor precise language of bidimensionality easy to represent in a rectangular coordinate system. In recent years, the importance of geometry has been re-emphasized by significant advances in the digital age, where computers are increasingly used in design, fabrication and construction to explore the art of the possible. Contemporary architecture transcend the limitations of Euclidean geometry and create new forms that are emerging through the convergence of complex systems, computational design and robotic fabrication devices, but which can also achieve higher levels of performance. Freeform architectural shapes and structures play an increasingly important role in 21st century architectural design. Through a series of examples, the paper relates to contemporary architectural explorations of complex, curvilinear surfaces in the digital age and discusses how it has required rethinking the mode in which we traditionally operate as architects. The analysis creates the possibility of comparisons between original and current design.

  12. Analogical Reasoning in Geometry Education

    Science.gov (United States)

    Magdas, Ioana

    2015-01-01

    The analogical reasoning isn't used only in mathematics but also in everyday life. In this article we approach the analogical reasoning in Geometry Education. The novelty of this article is a classification of geometrical analogies by reasoning type and their exemplification. Our classification includes: analogies for understanding and setting a…

  13. Algebraic Methods in Plane Geometry

    Indian Academy of Sciences (India)

    Srimath

    group, taxicab number, Carmi- chael number. Algebraic Methods in Plane Geometry. 2. Cubic Curves. Shailesh A Shirali. Shailesh Shirali heads a. Community Mathematics. Center at Rishi Valley. School (KFI). He has a ..... Ian Stewart and David Tall, Algebraic Number Theory and Fermat's Last. Theorem, A K Peters, 2002.

  14. Fractal geometry and stochastics IV

    CERN Document Server

    Bandt, Christoph

    2010-01-01

    Over the years fractal geometry has established itself as a substantial mathematical theory in its own right. This book collects survey articles covering many of the developments, like Schramm-Loewner evolution, fractal scaling limits, exceptional sets for percolation, and heat kernels on fractals.

  15. Learners engaging with transformation geometry

    African Journals Online (AJOL)

    able to move flexibly between the modes and who displayed a deep understanding of the concepts. ... However the strand remains in the curriculum for Grades R to 9, and will still provide rich learning opportunities ... There is limited available research on learners' understanding and learning of transformation geometry.

  16. Optimization Problems in Elementary Geometry

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 13; Issue 6. Optimization Problems in Elementary Geometry. A K Mallik. General Article Volume 13 Issue 6 June 2008 pp 561-582 ... Author Affiliations. A K Mallik1. Department Of Mechanical Engineering, Indian Institute of Technology, Kanpur, India.

  17. Multivariable calculus and differential geometry

    CERN Document Server

    Walschap, Gerard

    2015-01-01

    This text is a modern in-depth study of the subject that includes all the material needed from linear algebra. It then goes on to investigate topics in differential geometry, such as manifolds in Euclidean space, curvature, and the generalization of the fundamental theorem of calculus known as Stokes' theorem.

  18. Geometry of Cuts and Metrics

    NARCIS (Netherlands)

    M. Deza; M. Laurent (Monique)

    1997-01-01

    htmlabstractCuts and metrics are well-known objects that arise - independently, but with many deep and fascinating connections - in diverse fields: in graph theory, combinatorial optimization, geometry of numbers, combinatorial matrix theory, statistical physics, VLSI design etc. This book offers a

  19. Stochastic Modelling of River Geometry

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Schaarup-Jensen, K.

    1996-01-01

    Numerical hydrodynamic river models are used in a large number of applications to estimate critical events for rivers. These estimates are subject to a number of uncertainties. In this paper, the problem to evaluate these estimates using probabilistic methods is considered. Stochastic models for ...... for river geometries are formulated and a coupling between hydraulic computational methods and numerical reliability methods is presented....

  20. Axiomatic Differential Geometry Ⅱ-4

    OpenAIRE

    Nishimura, Hirokazu

    2012-01-01

    In our previous paper (Axiomatic Differential Geometry II-3) we havediscussed the general Jacobi identity, from which the Jacobi identity ofvector fields follows readily. In this paper we derive Jacobi-like identitiesof tangent-vector-valued forms from the general Jacobi identity.

  1. Axiomatic Differential Geometry II-3

    OpenAIRE

    Nishimura, Hirokazu

    2012-01-01

    As the fourth paper of our series of papers concerned with axiomatic differential geometry, this paper is devoted to the general Jacobi identity supporting the Jacobi identity of vector fields. The general Jacobi identity can be regarded as one of the few fundamental results belonging properly to smootheology.

  2. Axiomatic Differential Geometry II-4

    OpenAIRE

    Nishimura, Hirokazu

    2012-01-01

    In our previous paper (Axiomatic Differential Geometry II-3) we have discussed the general Jacobi identity, from which the Jacobi identity of vector fields follows readily. In this paper we derive Jacobi-like identities of tangent-vector-valued forms from the general Jacobi identity.

  3. Improving Student Reasoning in Geometry

    Science.gov (United States)

    Wong, Bobson; Bukalov, Larisa

    2013-01-01

    In their years of teaching geometry, Wong and Bukalov realized that the greatest challenge has been getting students to improve their reasoning. Many students have difficulty writing formal proofs--a task that requires a good deal of reasoning. Wong and Bukalov reasoned that the solution was to divide the lessons into parallel tasks, allowing…

  4. Fubini theorem in noncommutative geometry

    OpenAIRE

    Sukochev, Fedor; Zanin, Dmitriy

    2016-01-01

    We discuss the Fubini formula in Alain Connes' noncommutative geometry. We present a sufficient condition on spectral triples for which a Fubini formula holds true. The condition is natural and related to heat semigroup asymptotics. We provide examples of spectral triples for which the Fubini formula fails.

  5. Aesthetic preformed crowns for primary teeth.

    Science.gov (United States)

    Taylor, Greig D

    2017-06-23

    Data sourcesMedline, Cochrane central register of controlled trials, US National Institutes of Health Trials Register and the World Health Organization International Clinical Trials Registry Platform.Study selectionEnglish language randomised clinical trials comparing APCs with conventional restorative techniques for primary teeth.Data extraction and synthesisStudy selection and data abstraction were conducted independently by two reviewers. Risk of bias was assessed using the Cochrane risk of bias tool. Study characteristics and results were described qualitatively. Meta-analysis was not conducted.ResultsSeven studies were included, six reported on primary molars and one on primary incisors. There was great variety in the design of the RCTs, however, all compared pre-veneered stainless steel crowns (SSCs) with other crowns or two different pre-veneered SSCs. The risk of bias in all studies was high with significantly different outcome measures used.ConclusionsSSCs cannot be replaced by APCs for restoring decayed primary molar teeth due to the insufficient quality of evidence available. After a follow-up of only six months, zircon crowns gave significantly better results than the others regarding gingival health and crown fractures. Due to the small number of RCTs on this topic and their risk of bias, future RCTs should be carried out in primary teeth.

  6. Reconstruction of endodontically treated teeth: intraradicular retainers

    Directory of Open Access Journals (Sweden)

    Luciano Bonatelli Bispo

    2008-01-01

    Full Text Available There are many ways of restoring endodontically treated teeth. The quantity and quality of the dental remainder after endodontic treatment is questionable in terms of clinical longevity, not because of the coronal opening and therapy in themselves, but because of the destruction inherent to teeth affected by fractures and invasive carious processes. There are many commercial brands of posts and marketing artifices with the goal of maximizing resistance to masticatory forces. However, the major complexity found with regard to the definitive restoration is the doubt whether to insert a prefabricated post, cast metal or porcelain core as filling core. However, nothing is feasible if the parameters said to be safe were not used and the minimum mechanical requirements were not demanded. Growing commercial demand leads to unrestrained confusion in professionals that end up forgetting about or ignoring the minimum criteria demandable for a favorable prognosis. Compliance with the biomechanical bases is the most important parameter for increasing the quality of the intraradicular retainer. The aim of this study is to present basic techniques for more reliable restorations, maximizing the quality of the dental remainder when making extensive restorations that use intraradicular retainers in endodontically treated teeth.

  7. Geometry

    Indian Academy of Sciences (India)

    Limit: (of a sequence) A point such that the points of the sequence eventually approach it to within any previously specified distance. Some of the Greek mathematicians were quite confused! For example, let us take an empty cup and put it under a tap. Assume that it is half full in a minute. It is then 3/4-th full in another half.

  8. Geometry

    Indian Academy of Sciences (India)

    cartographer in the days before aerial travel) can determine the curvature. Hence the beauty of a surface is skin deep and yet is naturally associated with it! SERIES I ARTICLE cartographic surveys he was carrying out for the ruler of Germany) gave a new interpretation to Euler's theory. First consider the length of the vector t ...

  9. Geometry

    Indian Academy of Sciences (India)

    In order to utilise this Descartes devised the following scheme. By. fIXing a point, the origin, on a line it becomes possible to talk of a directed distance as a positive or negative number depending on whether the end point is to one or the other side of the origin. Similarly, he assigned a pair of numbers to every point of the.

  10. The epidemiology of supernumerary teeth and the associated molecular mechanism.

    Science.gov (United States)

    Lu, Xi; Yu, Fang; Liu, Junjun; Cai, Wenping; Zhao, Yumei; Zhao, Shouliang; Liu, Shangfeng

    2017-07-03

    Supernumerary teeth are common clinical dental anomalies. Although various studies have provided abundant information regarding genes and signaling pathways involved in tooth morphogenesis, which include Wnt, FGF, BMP, and Shh, the molecular mechanism of tooth formation, especially for supernumerary teeth, is still unclear. In the population, some cases of supernumerary teeth are sporadic, while others are syndrome-related with familial hereditary. The prompt and accurate diagnosis of syndrome related supernumerary teeth is quite important for some distinctive disorders. Mice are the most commonly used model system for investigating supernumerary teeth. The upregulation of Wnt and Shh signaling in the dental epithelium results in the formation of multiple supernumerary teeth in mice. Understanding the molecular mechanism of supernumerary teeth is also a component of understanding tooth formation in general and provides clinical guidance for early diagnosis and treatment in the future.

  11. Shark teeth as edged weapons: serrated teeth of three species of selachians.

    Science.gov (United States)

    Moyer, Joshua K; Bemis, William E

    2017-02-01

    Prior to European contact, South Pacific islanders used serrated shark teeth as components of tools and weapons. They did this because serrated shark teeth are remarkably effective at slicing through soft tissues. To understand more about the forms and functions of serrated shark teeth, we examined the morphology and histology of tooth serrations in three species: the Tiger Shark (Galeocerdo cuvier), Blue Shark (Prionace glauca), and White Shark (Carcharodon carcharias). We show that there are two basic types of serrations. A primary serration consists of three layers of enameloid with underlying dentine filling the serration's base. All three species studied have primary serrations, although the dentine component differs (orthodentine in Tiger and Blue Sharks; osteodentine in the White Shark). Smaller secondary serrations are found in the Tiger Shark, formed solely by enameloid with no contribution from underlying dentine. Secondary serrations are effectively "serrations within serrations" that allow teeth to cut at different scales. We propose that the cutting edges of Tiger Shark teeth, equipped with serrations at different scales, are linked to a diet that includes large, hard-shelled prey (e.g., sea turtles) as well as smaller, softer prey such as fishes. We discuss other aspects of serration form and function by making analogies to man-made cutting implements, such as knives and saws. Copyright © 2016 Elsevier GmbH. All rights reserved.

  12. Do wisdom teeth induce lower anterior teeth crowding? A systematic literature review.

    Science.gov (United States)

    Stanaitytė, Rūta; Trakinienė, Giedrė; Gervickas, Albinas

    2014-01-01

    Individuals with dental crowding are the most frequent patients in the orthodontic practice.The purpose of this article is to find out if the lower third molars are the main reason of crowding in the lower dental arch. As well to find out other factors which can influence the lower incisors crowding. The aim was to identify studies and reviews related to the effect of the lower third molars on the lower dental arch crowding. A literature survey was performed using Medline database. Used key words were lower third molar, influence of wisdom teeth, wisdom teeth and anterior crowding, lower dental arch changes. The articles from 1971 to 2011 related to topic were identified. Selected articles were published in dental journals in English. Full texts of the selected articles were analyzed. Articles about the dental crowding after orthodontic treatment were not included. All studies accomplished with human participants. It was found 223 articles but only 21 articles corresponded to selected criteria and were analyzed. This review is based on the investigations of 12 laboratory researchers, 4 clinical researches, 2 questionnaires and 3 literature reviews. The results are quite contradictory: some authors support the opinion that lower third molars cause teeth crowding, the others confirm conversy. Exist other factors affecting the mandibular incisors crowding: dental (teeth crown size, dental arch length loss, poor periodontal status and primary teeth loss), skeletal (growth of the jaws and malocclusion) and general (age and gender).

  13. Teething myths among nursing mothers in North-Western Nigeria

    Directory of Open Access Journals (Sweden)

    Ibrahim Aliyu

    2015-01-01

    Full Text Available Background: Teething has over the years been associated with complains of systemic symptoms from parents, and at times are over treated by health-care professionals. This study seeks to determine common teething complaints reported by nursing mothers. Materials and Methods: This study was multicenter involving 224 nursing mothers. It was cross-sectional and questionnaire-based relevant information collected were: The socio demographic characteristics, knowledge of teething and myths associated with teething, and the attitude of nursing mothers toward the use of teething remedies. Results: Two hundred and three (90.62% of them believed teething caused symptoms; common complaints that were attributed to teething by mothers were diarrhea, vomiting, increased salivation; however, fever was the predominant complaint, and their parents were the most common source of information on teething in 50% of them, while only a mother (0.4% was informed on the process of teething at the hospital. Furthermore, the number of children did not affect the desire to seek for medical care for teething symptoms. Common remedies used were as follows: 59 (26.3% nursing mothers used teething syrup, 43 (19.2% nursing mothers used teething powder, 16 (7.2% of them used traditional herbs while 8(3.6% of them used multiple preparations; however 91 (40.6% of them did not use any remedy. One hundred and seven (47.8% of the mothers believed that these remedies worked, 67 (29.9% of them disagreed while 50 (22.3% were not sure of their efficacy. Conclusion: Parents should be educated on normal expectations of the teething process; and not to undermine the seriousness of illnesses erroneously attributed to teething.

  14. Cleidocranial dysplasia presenting with retained deciduous teeth and impacted permanent and supernumerary teeth

    Directory of Open Access Journals (Sweden)

    Mahalakshmi Ikkanur Puttaranganaik

    2014-01-01

    Full Text Available Cleidocranial dysplasia is a disease that occurs secondary to a dominant autosomal inheritance. There is no predilection for any genre or ethnic group. As there is a delay in the eruption and/or absence of permanent teeth, the patients usually report to a dental surgeon for replacement of the missing teeth. This condition is characterized by several cranial malformations and underdevelopment, absence of clavicles, and multiple impacted supernumerary and permanent teeth. The diagnosis of the condition is usually based on the presence of the above-mentioned main features and on clinical and familial evidence. Here we report a rare case of cleidocranial dysplasia in a male patient, having most of the characteristic features of this syndrome.

  15. A Diagnostic and Therapeutic Algorithm for Impacted Teeth for Plastic Surgeons: Outcomes of 242 Extracted Teeth

    Directory of Open Access Journals (Sweden)

    Nebil Yeşiloğlu

    2016-09-01

    Full Text Available Objective: Impacted teeth are important for plastic surgeons that frequently perform maxillofacial operations because of their tendency to affect dental occlusion, and thus, cephalometric results. Moreover, severe complications are also caused by the tooth and its surgical removal. In this study, retrospective analysis of 242 extracted teeth and 24 extracted roots was performed and an algorithmic approach to different types and the localizations of impacted teeth was presented. Possible complications and salvage procedures were also discussed. Material and Methods: A retrospective analysis of 128 patients who underwent impacted teeth removal surgery between 2013 and 2015 was performed. Mean age was 26 years (Range: 18–42 years, and the female to male ratio was 39/89. Sixteen of the patients were operated under regional nerve block, whereas the remaining were operated under general anesthesia. In 107 patients, the whole tooth was removed, whereas the residual root of the tooth was removed in 21 patients. In 89 patients, bone interventions like the creation of bone window or peridental milling to loosen the tooth were needed, whereas only oral mucosal incisions were performed in the remaining patients. Results: The most common onset symptom was localized pain, and the most common complications were swelling and edema. The most common extracted tooth was the mandibular 3rd molar. Lower lip hypoesthesia, which was continued up to eight months, was encountered in six patients who underwent mandibular 3rd molar extraction. Conclusion: In our opinion, a wide range of possible complications secondary to impacted teeth surgery makes them important for plastic surgeons who are more experienced than other disciplines, and learning teeth extraction is essential to learn in plastic surgery specialty training.

  16. Grassmannian geometry of scattering amplitudes

    CERN Document Server

    Arkani-Hamed, Nima; Cachazo, Freddy; Goncharov, Alexander; Postnikov, Alexander; Trnka, Jaroslav

    2016-01-01

    Outlining a revolutionary reformulation of the foundations of perturbative quantum field theory, this book is a self-contained and authoritative analysis of the application of this new formulation to the case of planar, maximally supersymmetric Yang–Mills theory. The book begins by deriving connections between scattering amplitudes and Grassmannian geometry from first principles before introducing novel physical and mathematical ideas in a systematic manner accessible to both physicists and mathematicians. The principle players in this process are on-shell functions which are closely related to certain sub-strata of Grassmannian manifolds called positroids - in terms of which the classification of on-shell functions and their relations becomes combinatorially manifest. This is an essential introduction to the geometry and combinatorics of the positroid stratification of the Grassmannian and an ideal text for advanced students and researchers working in the areas of field theory, high energy physics, and the...

  17. Euclidean distance geometry an introduction

    CERN Document Server

    Liberti, Leo

    2017-01-01

    This textbook, the first of its kind, presents the fundamentals of distance geometry:  theory, useful methodologies for obtaining solutions, and real world applications. Concise proofs are given and step-by-step algorithms for solving fundamental problems efficiently and precisely are presented in Mathematica®, enabling the reader to experiment with concepts and methods as they are introduced. Descriptive graphics, examples, and problems, accompany the real gems of the text, namely the applications in visualization of graphs, localization of sensor networks, protein conformation from distance data, clock synchronization protocols, robotics, and control of unmanned underwater vehicles, to name several.  Aimed at intermediate undergraduates, beginning graduate students, researchers, and practitioners, the reader with a basic knowledge of linear algebra will gain an understanding of the basic theories of distance geometry and why they work in real life.

  18. Fractal geometry and computer graphics

    CERN Document Server

    Sakas, Georgios; Peitgen, Heinz-Otto; Englert, Gabriele

    1992-01-01

    Fractal geometry has become popular in the last 15 years, its applications can be found in technology, science, or even arts. Fractal methods and formalism are seen today as a general, abstract, but nevertheless practical instrument for the description of nature in a wide sense. But it was Computer Graphics which made possible the increasing popularity of fractals several years ago, and long after their mathematical formulation. The two disciplines are tightly linked. The book contains the scientificcontributions presented in an international workshop in the "Computer Graphics Center" in Darmstadt, Germany. The target of the workshop was to present the wide spectrum of interrelationships and interactions between Fractal Geometry and Computer Graphics. The topics vary from fundamentals and new theoretical results to various applications and systems development. All contributions are original, unpublished papers.The presentations have been discussed in two working groups; the discussion results, together with a...

  19. Geometry of area without length

    Science.gov (United States)

    Ho, Pei-Ming; Inami, Takeo

    2016-01-01

    To define a free string by the Nambu-Goto action, all we need is the notion of area, and mathematically the area can be defined directly in the absence of a metric. Motivated by the possibility that string theory admits backgrounds where the notion of length is not well defined but a definition of area is given, we study space-time geometries based on the generalization of a metric to an area metric. In analogy with Riemannian geometry, we define the analogues of connections, curvatures, and Einstein tensor. We propose a formulation generalizing Einstein's theory that will be useful if at a certain stage or a certain scale the metric is ill defined and the space-time is better characterized by the notion of area. Static spherical solutions are found for the generalized Einstein equation in vacuum, including the Schwarzschild solution as a special case.

  20. Foliation theory in algebraic geometry

    CERN Document Server

    McKernan, James; Pereira, Jorge

    2016-01-01

    Featuring a blend of original research papers and comprehensive surveys from an international team of leading researchers in the thriving fields of foliation theory, holomorphic foliations, and birational geometry, this book presents the proceedings of the conference "Foliation Theory in Algebraic Geometry," hosted by the Simons Foundation in New York City in September 2013.  Topics covered include: Fano and del Pezzo foliations; the cone theorem and rank one foliations; the structure of symmetric differentials on a smooth complex surface and a local structure theorem for closed symmetric differentials of rank two; an overview of lifting symmetric differentials from varieties with canonical singularities and the applications to the classification of AT bundles on singular varieties; an overview of the powerful theory of the variety of minimal rational tangents introduced by Hwang and Mok; recent examples of varieties which are hyperbolic and yet the Green-Griffiths locus is the whole of X; and a classificati...

  1. The geometry of celestial mechanics

    CERN Document Server

    Geiges, Hansjörg

    2016-01-01

    Celestial mechanics is the branch of mathematical astronomy devoted to studying the motions of celestial bodies subject to the Newtonian law of gravitation. This mathematical introductory textbook reveals that even the most basic question in celestial mechanics, the Kepler problem, leads to a cornucopia of geometric concepts: conformal and projective transformations, spherical and hyperbolic geometry, notions of curvature, and the topology of geodesic flows. For advanced undergraduate and beginning graduate students, this book explores the geometric concepts underlying celestial mechanics and is an ideal companion for introductory courses. The focus on the history of geometric ideas makes it perfect supplementary reading for students in elementary geometry and topology. Numerous exercises, historical notes and an extensive bibliography provide all the contextual information required to gain a solid grounding in celestial mechanics.

  2. Differential geometry and mathematical physics

    CERN Document Server

    Rudolph, Gerd

    Starting from an undergraduate level, this book systematically develops the basics of • Calculus on manifolds, vector bundles, vector fields and differential forms, • Lie groups and Lie group actions, • Linear symplectic algebra and symplectic geometry, • Hamiltonian systems, symmetries and reduction, integrable systems and Hamilton-Jacobi theory. The topics listed under the first item are relevant for virtually all areas of mathematical physics. The second and third items constitute the link between abstract calculus and the theory of Hamiltonian systems. The last item provides an introduction to various aspects of this theory, including Morse families, the Maslov class and caustics. The book guides the reader from elementary differential geometry to advanced topics in the theory of Hamiltonian systems with the aim of making current research literature accessible. The style is that of a mathematical textbook,with full proofs given in the text or as exercises. The material is illustrated by numerous d...

  3. Hyperbolic geometry for colour metrics.

    Science.gov (United States)

    Farup, Ivar

    2014-05-19

    It is well established from both colour difference and colour order perpectives that the colour space cannot be Euclidean. In spite of this, most colour spaces still in use today are Euclidean, and the best Euclidean colour metrics are performing comparably to state-of-the-art non-Euclidean metrics. In this paper, it is shown that a transformation from Euclidean to hyperbolic geometry (i.e., constant negative curvature) for the chromatic plane can significantly improve the performance of Euclidean colour metrics to the point where they are statistically significantly better than state-of-the-art non-Euclidean metrics on standard data sets. The resulting hyperbolic geometry nicely models both qualitatively and quantitatively the hue super-importance phenomenon observed in colour order systems.

  4. Groups and Geometries : Siena Conference

    CERN Document Server

    Kantor, William; Lunardon, Guglielmo; Pasini, Antonio; Tamburini, Maria

    1998-01-01

    On September 1-7, 1996 a conference on Groups and Geometries took place in lovely Siena, Italy. It brought together experts and interested mathematicians from numerous countries. The scientific program centered around invited exposi­ tory lectures; there also were shorter research announcements, including talks by younger researchers. The conference concerned a broad range of topics in group theory and geometry, with emphasis on recent results and open problems. Special attention was drawn to the interplay between group-theoretic methods and geometric and combinatorial ones. Expanded versions of many of the talks appear in these Proceedings. This volume is intended to provide a stimulating collection of themes for a broad range of algebraists and geometers. Among those themes, represented within the conference or these Proceedings, are aspects of the following: 1. the classification of finite simple groups, 2. the structure and properties of groups of Lie type over finite and algebraically closed fields of f...

  5. Preformed crowns for decayed primary molar teeth.

    Science.gov (United States)

    Innes, Nicola P T; Ricketts, David; Chong, Lee Yee; Keightley, Alexander J; Lamont, Thomas; Santamaria, Ruth M

    2015-12-31

    Crowns for primary molars are preformed and come in a variety of sizes and materials to be placed over decayed or developmentally defective teeth. They can be made completely of stainless steel (know as 'preformed metal crowns' or PMCs), or to give better aesthetics, may be made of stainless steel with a white veneer cover or made wholly of a white ceramic material. In most cases, teeth are trimmed for the crowns to be fitted conventionally using a local anaesthetic. However, in the case of the Hall Technique, PMCs are pushed over the tooth with no local anaesthetic, carious tissue removal or tooth preparation. Crowns are recommended for restoring primary molar teeth that have had a pulp treatment, are very decayed or are badly broken down. However, few dental practitioners use them in clinical practice. This review updates the original review published in 2007. Primary objectiveTo evaluate the clinical effectiveness and safety of all types of preformed crowns for restoring primary teeth compared with conventional filling materials (such as amalgam, composite, glass ionomer, resin modified glass ionomer and compomers), other types of crowns or methods of crown placement, non-restorative caries treatment or no treatment. Secondary objectiveTo explore whether the extent of decay has an effect on the clinical outcome of primary teeth restored with all types of preformed crowns compared with those restored with conventional filling materials. We searched the following electronic databases: Cochrane Oral Health Group Trials Register (to 21 January 2015), Cochrane Central Register of Controlled Trials (CENTRAL; The Cochrane Library, 2014, Issue 12), MEDLINE via Ovid (1946 to 21 January 2015) and EMBASE via Ovid (1980 to 21 January 2015). We searched the US National Institutes of Health Trials Register (http://clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform for ongoing trials and Open Grey for grey literature (to

  6. General Relativity by Kawaguchi geometry

    Directory of Open Access Journals (Sweden)

    Tanaka Erico

    2013-09-01

    Full Text Available We construct a parameterisation invariant Lagrange theory of fields up to second order by using multivector bundles and Kawaguchi geometry. In this setup, the spacetime is an dynamical object which is a submanifold of the greater manifold, and the actual spacetime is the solution of Euler-Lagrange equations. Such theory is a reasonable mathematical foundation to describe an extended theory of Einstein’s general relativity, and is capable of being a stage for unification with other physical fields.

  7. Geometry Dependence of Stellarator Turbulence

    Energy Technology Data Exchange (ETDEWEB)

    H.E. Mynick, P. Xanthopoulos and A.H. Boozer

    2009-08-10

    Using the nonlinear gyrokinetic code package GENE/GIST, we study the turbulent transport in a broad family of stellarator designs, to understand the geometry-dependence of the microturbulence. By using a set of flux tubes on a given flux surface, we construct a picture of the 2D structure of the microturbulence over that surface, and relate this to relevant geometric quantities, such as the curvature, local shear, and effective potential in the Schrodinger-like equation governing linear drift modes.

  8. Topics in modern differential geometry

    CERN Document Server

    Verstraelen, Leopold

    2017-01-01

    A variety of introductory articles is provided on a wide range of topics, including variational problems on curves and surfaces with anisotropic curvature. Experts in the fields of Riemannian, Lorentzian and contact geometry present state-of-the-art reviews of their topics. The contributions are written on a graduate level and contain extended bibliographies. The ten chapters are the result of various doctoral courses which were held in 2009 and 2010 at universities in Leuven, Serbia, Romania and Spain.

  9. Age-Dependent Changes in Pb Concentration in Human Teeth.

    Science.gov (United States)

    Fischer, Agnieszka; Wiechuła, Danuta

    2016-09-01

    The result of exposure to Pb is its accumulation in mineralized tissues. In human body, they constitute a reservoir of approx. 90 % of the Pb reserve. The conducted research aimed at determining the accumulation of Pb in calcified tissues of permanent teeth. The concentration of Pb in 390 samples of teeth taken from a selected group of Polish people was determined using the AAS method. Average concentration of Pb in teeth amounted to 14.3 ± 8.18 μg/g, range of changes: 2.21-54.8 μgPb/g. Accumulation of Pb in human body was determined based on changes in Pb concentration in teeth of subjects aged 13-84 years. It was found that in calcified tissues of teeth, the increase in concentration of Pb that occurs with age is a statistically significant process (p = 0.02, the ANOVA Kruskal-Wallis test). It was determined that the annual increase in concentration of Pb in tissues of teeth is approx. 0.1 μg/g. Moreover, a different course of changes in Pb concentration in tissues of teeth in people born in different years was observed. The level of Pb concentration in teeth of the oldest subjects (>60 years) decreased for those born in the 1930s compared to those in the 1950s. Teeth from younger persons (teeth can occur.

  10. Riemannian geometry and geometric analysis

    CERN Document Server

    Jost, Jürgen

    2017-01-01

    This established reference work continues to provide its readers with a gateway to some of the most interesting developments in contemporary geometry. It offers insight into a wide range of topics, including fundamental concepts of Riemannian geometry, such as geodesics, connections and curvature; the basic models and tools of geometric analysis, such as harmonic functions, forms, mappings, eigenvalues, the Dirac operator and the heat flow method; as well as the most important variational principles of theoretical physics, such as Yang-Mills, Ginzburg-Landau or the nonlinear sigma model of quantum field theory. The present volume connects all these topics in a systematic geometric framework. At the same time, it equips the reader with the working tools of the field and enables her or him to delve into geometric research.  The 7th edition has been systematically reorganized and updated. Almost no page has been left unchanged. It also includes new material, for instance on symplectic geometry, as well as the B...

  11. Number theory III Diophantine geometry

    CERN Document Server

    1991-01-01

    From the reviews of the first printing of this book, published as Volume 60 of the Encyclopaedia of Mathematical Sciences: "Between number theory and geometry there have been several stimulating influences, and this book records of these enterprises. This author, who has been at the centre of such research for many years, is one of the best guides a reader can hope for. The book is full of beautiful results, open questions, stimulating conjectures and suggestions where to look for future developments. This volume bears witness of the broad scope of knowledge of the author, and the influence of several people who have commented on the manuscript before publication ... Although in the series of number theory, this volume is on diophantine geometry, and the reader will notice that algebraic geometry is present in every chapter. ... The style of the book is clear. Ideas are well explained, and the author helps the reader to pass by several technicalities. Reading and rereading this book I noticed that the topics ...

  12. Introduction to geometry and relativity

    CERN Document Server

    2013-01-01

    This book provides a lucid introduction to both modern differential geometry and relativity for advanced undergraduates and first-year graduate students of applied mathematics and physical sciences. This book meets an overwhelming need for a book on modern differential geometry and relativity that is student-friendly, and which is also suitable for self-study. The book presumes a minimal level of mathematical maturity so that any student who has completed the standard Calculus sequence should be able to read and understand the book. The key features of the book are: Detailed solutions are provided to the Exercises in each chapter; Many of the missing steps that are often omitted from standard mathematical derivations have been provided to make the book easier to read and understand; A detailed introduction to Electrodynamics is provided so that the book is accessible to students who have not had a formal course in this area; In its treatment of modern differential geometry, the book employs both a modern, c...

  13. Aspects of differential geometry II

    CERN Document Server

    Gilkey, Peter

    2015-01-01

    Differential Geometry is a wide field. We have chosen to concentrate upon certain aspects that are appropriate for an introduction to the subject; we have not attempted an encyclopedic treatment. Book II deals with more advanced material than Book I and is aimed at the graduate level. Chapter 4 deals with additional topics in Riemannian geometry. Properties of real analytic curves given by a single ODE and of surfaces given by a pair of ODEs are studied, and the volume of geodesic balls is treated. An introduction to both holomorphic and Kähler geometry is given. In Chapter 5, the basic properties of de Rham cohomology are discussed, the Hodge Decomposition Theorem, Poincaré duality, and the Künneth formula are proved, and a brief introduction to the theory of characteristic classes is given. In Chapter 6, Lie groups and Lie algebras are dealt with. The exponential map, the classical groups, and geodesics in the context of a bi-invariant metric are discussed. The de Rham cohomology of compact Lie groups an...

  14. [Determination of placement of anterior teeth in removable dental prostheses].

    Science.gov (United States)

    Strajnić, Ljiljana

    2002-01-01

    The aim of this paper was to present methods of placement of artificial anterior teeth in edentulous individuals. The following review takes account of the majority of papers published during the last 100 years. The review has been divided into sections regarding the method used to determine the position of artificial anterior teeth. Gysi (1895-1920) produced the first scientific theory about the position of artificial anterior teeth. The aim of this theory is to find the most natural position for artificial anterior teeth for each individual. Camper's "face angle" as a physiognomic criterion, has been introduced in papers of Wehrli (1961), Marxhors (1966). Tanzer (1968). Lombardi (1973). Important names in the field of dental esthetics are: Schn and Singer (1961), Arnheim (1965), Krajicek (1969), Tanzer (1968), Lombardi (1973), Goldstein (1976). They have introduced principes of visual aspects for selection of contours, dimension and position of artificial anterior teeth. Flagg (1880), Williams (1913) and Hrauf (1957, 1958), have considered body constitution and individual characteristics regarding position of artifical anterior teeth. In 1971, Maxhors pointed to the fact that the position of artificial teeth corresponds with the function of the surrounding soft tissue and from the aspect of physiognomy as well. According to Silverman (1962) artificial anterior teeth are nearest when we pronounce the sound "S". Rayson (1970), Watson (1989), Strajnić Lj. (1999), Bassi F. (2001) have presented cephalometric radiographic analyses of natural anterior teeth compared with cephalometric radiographic analyses of artificial anterior teeth. A review of dental literature shows several factors suggesting modalities which should determine the position of artificial anterior teeth. Numerous methods have been designed for evaluation of the position of artificial anterior teeth. However, there is no universally reliable method regarding determination of the position of

  15. Clinical Characteristics of Abutment Teeth with Gingival Discoloration.

    Science.gov (United States)

    Ristic, Ljubisa; Dakovic, Dragana; Postic, Srdjan; Lazic, Zoran; Bacevic, Miljana; Vucevic, Dragana

    2017-04-06

    The grey-bluish discoloration of gingiva (known as "amalgam tattoo") does not appear only in the presence of amalgam restorations. It may also be seen in cases of teeth restored with cast dowels and porcelain-fused-to-metal (PFM) restorations. The aim of this article was to determine the clinical characteristics of abutment teeth with gingival discoloration. This research was conducted on 25 patients referred for cast dowel and PFM restorations. These restorations were manufactured from Ni-Cr alloys. Ninety days after cementing the fixed prosthodontic restorations, the abutment teeth (n = 61) were divided into a group with gingival discoloration (GD) (n = 25) and without gingival discoloration (NGD) (n = 36). The control group (CG) comprised the contralateral teeth (n = 61). Plaque index, gingival index, clinical attachment level, and probing depth were assessed before fabrication and also 90 days after cementation of the PFM restorations. The gingival index, clinical attachment level, and probing depths of the abutment teeth that had GD were statistically higher before restoration, in comparison with the abutment teeth in the NGD and control groups. Ninety days after cementation, the abutment teeth with GD had significantly lower gingival indexes and probing depths, compared to the abutment teeth in the NGD group. Both abutment teeth groups (GD and NGD) had significantly higher values of clinical attachment levels when compared to the control group. There were no statistically significant differences in plaque index values between the study groups. The results of this study indicated that impairment of periodontal status of abutment teeth seemed to be related to the presence of gingival discolorations. Therefore, fabrication of fixed prosthodontic restorations requires careful planning and abutment teeth preparation to minimize the occurrence of gingival discolorations. With careful preparation of abutment teeth for cast dowels and crown restorations it may be

  16. Algebraic Geometry and Number Theory Summer School

    CERN Document Server

    Sarıoğlu, Celal; Soulé, Christophe; Zeytin, Ayberk

    2017-01-01

    This lecture notes volume presents significant contributions from the “Algebraic Geometry and Number Theory” Summer School, held at Galatasaray University, Istanbul, June 2-13, 2014. It addresses subjects ranging from Arakelov geometry and Iwasawa theory to classical projective geometry, birational geometry and equivariant cohomology. Its main aim is to introduce these contemporary research topics to graduate students who plan to specialize in the area of algebraic geometry and/or number theory. All contributions combine main concepts and techniques with motivating examples and illustrative problems for the covered subjects. Naturally, the book will also be of interest to researchers working in algebraic geometry, number theory and related fields.

  17. Geometry success in 20 minutes a day

    CERN Document Server

    LLC, LearningExpress

    2014-01-01

    Whether you're new to geometry or just looking for a refresher, Geometry Success in 20 Minutes a Day offers a 20-step lesson plan that provides quick and thorough instruction in practical, critical skills. Stripped of unnecessary math jargon but bursting with geometry essentials, Geometry Success in 20 Minutes a Day: Covers all vital geometry skills, from the basic building blocks of geometry to ratio, proportion, and similarity to trigonometry and beyond Provides hundreds of practice exercises in test format Applies geometr

  18. Thermographic analysis of surface damage in teeth

    Science.gov (United States)

    Conde-Contreras, M.; Bante-Guerra, J.; Hernandez-Garcia, E.; Hernandez, A. M.; Trujillo, S.; Quintana, P.; Alvarado-Gil, J. J.

    2008-02-01

    The analysis of the surface of teeth is an important field of research and technological development due to the importance of dental pieces in health and aesthetics. The presence of cracks as well as the etching effects on teeth surface, due to different chemical agents, affects not only the appearance of teeth but its integrity. In this work, laser thermography analysis of dental pieces with damage in the form of cracks is presented. The technique consists in the illumination of the surface at the center of the sample, using a 300 mW pulsed solid state laser beam focused with a gradium lens, and monitoring the spatial and temporal distribution of the temperature field. The heating of the sample is monitored using a focal plane array infrared camera, sensitive in the spectral range 7.5-13 μm with a noise equivalent temperature difference of 0.12°C. The data acquisition was performed by the PC firewire port using a PCI-8254R card and a home-made program in Labview 8.0 was used for data acquisition. The images were processed in a home-made linux program to obtain the experimental table values. Our results are compared with position and frequency scans obtained by infrared photothermal radiometry. It is shown that the crack in the tooth appears as an increase in the photothermal signal. In contrast, the thermographic image shows a more detailed structure in which close to the crack the temperature increases, but at the crack the signal falls.

  19. A review on anterior teeth restorations

    Directory of Open Access Journals (Sweden)

    Gaurav Solanki

    2014-12-01

    Full Text Available Restorations of teeth have been a need of time since very long. As the time have passed, there have been different advances in the field of restorative materials and tooth restorations. Many newer restorative materials are now available to us for the purpose of tooth restorations still some of the older materials are materials of choice for a sector of society. This article focuses on few such restorative materials and also tells us about a few patents granted in such field.

  20. Tutankhamun's Dentition: The Pharaoh and his Teeth.

    Science.gov (United States)

    Pausch, Niels Christian; Naether, Franziska; Krey, Karl Friedrich

    2015-01-01

    Tutankhamun was a Pharaoh of the 18th Dynasty (New Kingdom) in ancient Egypt. Medical and radiological investigations of his skull revealed details about the jaw and teeth status of the mummy. Regarding the jaw relation, a maxillary prognathism, a mandibular retrognathism and micrognathism have been discussed previously. A cephalometric analysis was performed using a lateral skull X-ray and a review of the literature regarding King Tutankhamun´s mummy. The results imply diagnosis of mandibular retrognathism. Furthermore, third molar retention and an incomplete, single cleft palate are present.

  1. Complex aesthetic treatment on anterior maxillary teeth with malposition

    Directory of Open Access Journals (Sweden)

    Febriastuti Febriastuti

    2008-12-01

    Full Text Available Background: Complex aesthetic treatment on anterior teeth involves more than one caries tooth with malformed shape and malposition. Purpose: The purpose of this paper is to find the alternative treatment for anterior maxillary teeth with malposition. Case: In this case, a 25 year-old man with a peg shaped teeth and caries on several teeth and malposition can be treated with complex aesthetic treatment. Case management: Endodontic pulpectomy treatment on anterior maxillary teeth and post construction with splint porcelain fused to metal crowns on 11, 12, and 21, 22 to correct the shape and position into normal position. Conclusion: Malformed and malpositioned teeth with caries can be treated with complex aesthetic treatment.

  2. Chediak-Higashi Syndrome and Premature Exfoliation of Primary Teeth

    OpenAIRE

    Rezende,Karla Mayra; Canela,Alfredo Hiram Carrillo; Ortega,Adriana Oliveira Lira; Tintel,Claudia; Bonecker,Marcelo

    2013-01-01

    The Chediak-Higashi syndrome (CHS) is a rare hereditary fatal disease, if not treated. These changes are associated with various diseases and syndromes that mainly cause periodontal disease and thus the premature loss of teeth. This paper describes the monitoring of premature loss of primary teeth that began when the child was 5 years old. On presentation his teeth were mobile and there was a history of gingival bleeding. Panoramic radiography revealed generalized and severe bone loss, and th...

  3. Anatomical, pathological and clinical study of donkey teeth

    OpenAIRE

    Du Toit, Nicole

    2009-01-01

    Eighty normal cheek teeth and 26 normal incisors extracted from 14 donkeys (median age 19 years) at post mortem were anatomically examined including grossly and by computerised axial tomography (CAT) imaging. Decalcified histology was performed on 54 sections from 18 teeth (8 donkeys), undeclacified histology on 16 sections from 7 donkeys and scanning electron microscopy on 10 sections from 10 teeth (3 donkeys). The dental formulae and tooth number was found to be the same as i...

  4. Rare molariform supernumerary teeth: Why are they bilateral?

    Directory of Open Access Journals (Sweden)

    Parul Jain

    2017-01-01

    Full Text Available Anterior supernumerary teeth in the permanent dentition may be supplemental or rudimentary. Rudimentary types are further classified as conical, tuberculate, and molariform. The molariform type has been only rarely reported. We report a rare variety of anterior supernumerary teeth - the molariform type, occurring bilaterally and in association with a midline supernumerary tooth. We also suggest a hypothesis for the bilateral occurrence of supernumerary teeth.

  5. Histopathologic study on irradiated human developing teeth

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Yasunori (Iwate Medical Coll., Morioka (Japan). School of Dentistry)

    1982-12-01

    The patient was a 7-year-old boy who had been suffering from Ewing's sarcoma originating in the mandible. Irradiation with 8000 rad of Linac was performed on the mandible prior to mandibulectomy. The results of the histopathologic examination of the teeth including resected material were as follows: 1. Although the tumor tissue was not found in the resected material, complete resoption of the medullar trabecular bone with fibrosis was noted in the area between the first molar region and the mandibular ramus. 2. The first and the second premolar teeth were in the early stage of root formation, and conglomerates of dysplastic dentin were formed in the proliferative zones. This dysplastic dentin was surrounded by loose fibrous connective tissues. 3. The dysplastic dentin showed low mineralization, embedded irregular arranged-fibrous tissue matrix and scattered various-sized lacunae containing a few tiny and pyknotic cells. 4. Irregularly arranged odontoblasts with a pyknotic appearance were found along the tubular dentin, but diffuse fibrosis occurred in the pulpal tissues. 5. The first molar tooth had completed its root formation. Various amounts of osteodentin were formed at the secondary dentin layer. Inner-resorption of dentin and fibrosis of the pulpal tissue were also found. These changes concerning the first molar tooth were also due to the effects of irradiation. 6. The second molar tooth was resorbed by tumor infiltration, and dysplastic dentin was on the resorbed surface of the dentin.

  6. The fossil teeth of the Peking Man.

    Science.gov (United States)

    Xing, Song; Martinón-Torres, María; Bermúdez de Castro, José María

    2018-02-01

    This study provides new original data, including the endostructure of most Zhoukoudian H. erectus teeth preserved to date, since the publication of Black in 1927 and Weidenreich in 1937. The new evidence ratifies the similarities of Zhoukoudian with other East Asian mid-Middle Pleistocene hominins such as Hexian and Yiyuan, and allows defining a dental pattern potentially characteristic of this population commonly referred to as classic H. erectus. Given the possible chronological overlaps of classic H. erectus with other archaic Homo, the characterization of this group becomes a key issue when deciphering the taxonomy and evolutionary scenario of the Middle Pleistocene hominins in East Asia. Internally, the most remarkable feature of Zhoukoudian teeth is the highly crenulated enamel-dentine junction (EDJ) and its imprint on the roof of the pulp cavity. So far, this "dendrite-like" EDJ has been found only in East Asia Middle Pleistocene hominins although a large group of samples were assessed, and it could be useful to dentally define classic H. erectus in China. The crenulated EDJ surface, together with the stout roots and the taurodontism could be a mechanism to withstand high biomechanical demand despite a general dentognathic reduction, particularly of the crowns, in these populations.

  7. Root Canal Treatment for Deciduous Teeth: A Review

    Directory of Open Access Journals (Sweden)

    Müge Daloğlu

    2017-08-01

    Full Text Available The early loss of deciduous teeth leads to many negations in terms of physiological, functional and aesthetic. The structure of the deciduous teeth causes decay to progress much easier and less time and this is the need for frequent dental pulp treatment to be kept in the mouth. The new materials that will increase the success of deciduous teeth root canal treatment are continuing to investigate. In this study, it is aimed that recently prominent current approaches are to be compiled in root canal treatment of deciduous teeth.

  8. Triplication of deciduous teeth: A rare dental anomaly

    Directory of Open Access Journals (Sweden)

    Suresh Yadav

    2013-01-01

    Full Text Available Fusion of teeth is the union of two or more tooth germs, which are usually separated. Depending upon the stage of odontogenesis, it can be complete or incomplete. The present case describes fusion between the maxillary primary right central and lateral incisor with a supernumerary tooth. Clinical and radiographic examination revealed the presence of fused triple teeth. The fused teeth were extracted, sectioned and were visualized under stereomicroscope at three levels and the diagnosis of fusion of three teeth was confirmed histologically.

  9. Parental knowledge and practices on infant teething, Taif, Saudi Arabia.

    Science.gov (United States)

    Elbur, Abubaker Ibrahim; Yousif, M A; Albarraq, Ahmed Abdulrahman; Abdallah, Mustafa A

    2015-11-23

    Parents' false beliefs about signs and symptoms associated with teething have been documented in many studies around the world. This study was conducted to assess parental knowledge on infant teething process and to investigate parents' practices used to alleviate teething disturbances. A cross-sectional survey was conducted among parents of children of 6 months-5 years old in Taif, Saudi Arabia during April 2013. Convenience method of sampling was adopted and the data was collected by mean of a structured-questionnaire. Data was processed by SPPS. Logistic regression analysis was performed. P value parents attributed one or more of the listed signs and symptoms to teething process. Desire to bite, fever, gum irritation, increased salivation and diarrhea were the most reported signs and symptoms of teething by 459 (93.1%), 429 (87%), 415 (84.2%), 414 (84%) and 409 (83%) of the parents respectively. The only predictor of ascribing fever as a sign of infant teething was female gender (P = 0.001). However, female gender (P parents responded correctly to all questions designed to assess their knowledge on teething process. Wide gaps in parents' knowledge and practices related infant teething was identified. Educational interventions are needed to upgrade parents' knowledge and improve their practices regarding infant teething process.

  10. Exodontics: extraction of teeth in the dog and cat.

    Science.gov (United States)

    Gengler, Bill

    2013-05-01

    Dental disease can have a profound effect on the comfort and well-being of pets. Oral disease can be difficult to detect. Patients often hide their discomfort. The identification and treatment or removal of diseased teeth are the responsibility of the veterinarian. When diseased teeth cannot be saved by specialized care, extraction of teeth is necessary. Proper extraction of teeth in dogs and cats can be challenging and frustrating, but with review of the oral anatomy, proper instrumentation, and gentle tissue-handling techniques, this can be a rewarding part of clinical practice. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. Characteristics, clinical features and treatment of supernumerary teeth.

    Science.gov (United States)

    Yassin, Othman M; Hamori, Eman

    2009-01-01

    To determine the characteristics, clinical features and treatment of supernumerary teeth in a general district hospital in the North of Jordan. This retrospective study was conducted at Prince Rashid Al-Hassan Hospital in Irbid. The medical records of 139 patients who were diagnosed to have supernumerary teeth during the period April 1993 - June 2007 were reviewed. Clinical data on the location, number eruption status, stages of development, and the types of supernumerary teeth were recorded, along with information on demographics, treatment, associated systemic syndromes, effects on adjacent teeth, and treatment. The male to female ratio was 2.2:1. Of the 186 supernumerary teeth investigated (65.0%) were conical, (23.7%) supplemental, (10.8%) tuberculate and (0.5%) odontoma. Two-thirds of the supernumeraries were erupted. Of this sample (21.6%) patients had multiple supernumerary teeth. The most frequent location was at the premaxilla level. The most common effect on adjacent teeth was delayed eruption (23.1%). Simple and surgical extractions of supernumerary teeth were done for (81.7%) of the cases and orthodontic treatment was needed in (74.1%) of patients. Supernumerary teeth are an uncommon dental entity. An early diagnosis prevents or reduces the risk of complications and when combined with an earlier removal has a better prognosis.

  12. Prevalence of supernumerary teeth in deciduous and mixed dentition.

    Science.gov (United States)

    Dash, J K; Sahoo, P K; Das, S; Mohanty, U K

    2003-03-01

    Supernumerary teeth are the extra teeth which may have either erupted or unerupted in addition to normal dentition and are seen both in deciduous as well as permanent dentition. The incidence of supernumerary teeth shows more frequent occurrence in permanent dentition than deciduous dentition, affecting both the sexes. The etiology of supernumerary teeth is still unknown and not well understood, but thought to be the result from disturbance during the initiation and proliferation stages of tooth development. In the present study an attempt has been made to asses, its prevalence in deciduous and mixed dentition phase.

  13. Impacted supernumerary teeth: a survey of 50 cases.

    Science.gov (United States)

    Nazif, M M; Ruffalo, R C; Zullo, T

    1983-02-01

    Supernumerary teeth are considered one of the most significant dental anomalies during the primary and early mixed dentition stages. A total of 50 patients, ranging in age from 16 months to 17 years, were studied before, during, and after the surgical removal of their supernumerary teeth. Early removal of such teeth is recommended if they impede the eruption of adjacent permanent teeth, appear inverted or rudimentary, or if they are associated with certain pathological conditions. Complications associated with early removal are infrequent and seem minor in nature.

  14. Predictable management of cracked teeth with reversible pulpitis.

    Science.gov (United States)

    Abbott, P; Leow, N

    2009-12-01

    The aims of this study were to assess symptoms and signs caused by cracks in teeth and to assess a conservative management protocol. The symptoms and signs of 100 consecutive teeth that had reversible pulpitis associated with cracks were compared to findings from other reports. Teeth were managed with a conservative protocol which involved removal of cracks, caries and restorations, followed by placement of a sedative lining and interim restoration unless there were pulp exposures or insufficient tooth structure remaining. Teeth were monitored for pulp healing after three months and for up to five years. Eighty teeth did not require endodontic treatment. One tooth had an uncertain pulp status at review appointments. Fifteen teeth required endodontic treatment at the initial appointment because of carious pulp exposures (4 teeth), cracks extending into the pulp (2), and posts required (9). Four other teeth required endodontic treatment later following conservative pulp treatment due to continued pulpitis under the temporary restoration (1), pulpitis after core restoration (2), and pulp necrosis diagnosed at the review (1). Provided there is an accurate diagnosis of the pulp status and its cause, teeth with reversible pulpitis due to cracks can be treated conservatively without endodontic treatment in about 80 per cent of cases.

  15. Supernumerary teeth: Review of literature and decision support system

    Directory of Open Access Journals (Sweden)

    Deepti Amarlal

    2013-01-01

    Full Text Available Supernumerary teeth are those which are additional or in excess of the normal number. They can be either single or multiple, unilateral or bilateral and can be present anywhere in the dental arch with predilection for the premaxilla. Supernumerary teeth are mostly classified on position and form. Timing of surgical intervention of supernumerary teeth has been controversial with various authors having different opinions. Hence a new decision support system is put forward which can help in the treatment planning of supernumerary teeth.

  16. Immunohistochemical studies of the periodontal membrane in primary teeth

    DEFF Research Database (Denmark)

    Bille, Marie-Louise Bastholm; Nolting, Dorrit; Kjær, Inger

    2009-01-01

    Objectives. To describe the periodontal membrane of human primary teeth immunohistochemically, while focusing on the epithelial layer of Malassez, fibers, and peripheral nerves, and to compare the findings with those of a previous study of human permanent teeth. Material and methods. Nineteen human...... could be identical to those in regions with no resorption. Conclusion. In regions without resorption, spatial organization of the periodontal membrane of primary teeth was similar to that of permanent teeth, although the number and distribution of epithelial cells and fibers differed. In regions...

  17. Blow-Ups in Generalized Complex Geometry

    NARCIS (Netherlands)

    van der Leer Duran, J.L.

    2016-01-01

    Generalized complex geometry is a theory that unifies complex geometry and symplectic geometry into one single framework. It was introduced by Hitchin and Gualtieri around 2002. In this thesis we address the following question: given a generalized complex manifold together with a submanifold, does

  18. Geometry in the Early Years: A Commentary

    Science.gov (United States)

    Dindyal, Jaguthsing

    2015-01-01

    The primary goal of this paper is to provide a commentary on the teaching and learning of geometry in the early years of schooling with the set of papers in this issue as a guiding factor. It is structured around issues about geometry education of young learners, such as: what should we teach in geometry and why; representation of geometrical…

  19. Global affine differential geometry of hypersurfaces

    CERN Document Server

    Li, An-Min; Zhao, Guosong; Hu, Zejun

    2015-01-01

    This book draws a colorful and widespread picture of global affine hypersurface theory up to the most recent state. Moreover, the recent development revealed that affine differential geometry- as differential geometry in general- has an exciting intersection area with other fields of interest, like partial differential equations, global analysis, convex geometry and Riemann surfaces.

  20. Geometry of Space-Time

    Directory of Open Access Journals (Sweden)

    Bruchholz U. E.

    2009-10-01

    Full Text Available The geometry of the space-time is deduced from gravitational and electromagnetic fields. We have to state that Rainich's "already unified field theory" is the ground work of the proposed theory. The latter is deduced independently on Rainich. Rainich's analogies are brilliantly validated. His formulae are verified this way. Further reaching results and insights demonstrate that Rainich's theory is viable. In final result, we can formulate an enhanced equivalence principle. It is the equivalence of Newton's force with the Lorentz force.

  1. The Geometry Of Preposition Meanings

    Directory of Open Access Journals (Sweden)

    Peter Gärdenfors

    2015-12-01

    Full Text Available This article presents a unified approach to the semantics of prepositions based on the theory of conceptual spaces. Following the themes of my recent book The Geometry of Meaning, I focus on the convexity of their meanings and on which semantic domains are expressed by prepositions. As regards convexity, using polar coordinates turns out to provide the most natural representation. In addition to the spatial domain, I argue that for many prepositions, the force domain is central. In contrast to many other analyses, I also defend the position that prepositions have a central meaning and that other meanings can be derived via a limited class of semantic transformations.

  2. The geometry of musical chords.

    Science.gov (United States)

    Tymoczko, Dmitri

    2006-07-07

    A musical chord can be represented as a point in a geometrical space called an orbifold. Line segments represent mappings from the notes of one chord to those of another. Composers in a wide range of styles have exploited the non-Euclidean geometry of these spaces, typically by using short line segments between structurally similar chords. Such line segments exist only when chords are nearly symmetrical under translation, reflection, or permutation. Paradigmatically consonant and dissonant chords possess different near-symmetries and suggest different musical uses.

  3. Porous media geometry and transports

    CERN Document Server

    Adler, Pierre

    1992-01-01

    The goal of ""Porous Media: Geometry and Transports"" is to provide the basis of a rational and modern approach to porous media. This book emphasizes several geometrical structures (spatially periodic, fractal, and random to reconstructed) and the three major single-phase transports (diffusion, convection, and Taylor dispersion).""Porous Media"" serves various purposes. For students it introduces basic information on structure and transports. Engineers will find this book useful as a readily accessible assemblage of al the major experimental results pertaining to single-phase tr

  4. Integral geometry and representation theory

    CERN Document Server

    Gel'fand, I M; Vilenkin, N Ya

    1966-01-01

    Generalized Functions, Volume 5: Integral Geometry and Representation Theory is devoted to the theory of representations, focusing on the group of two-dimensional complex matrices of determinant one.This book emphasizes that the theory of representations is a good example of the use of algebraic and geometric methods in functional analysis, in which transformations are performed not on the points of a space, but on the functions defined on it. The topics discussed include Radon transform on a real affine space, integral transforms in the complex domain, and representations of the group of comp

  5. Projective differential geometry of submanifolds

    CERN Document Server

    Akivis, M A

    1993-01-01

    In this book, the general theory of submanifolds in a multidimensional projective space is constructed. The topics dealt with include osculating spaces and fundamental forms of different orders, asymptotic and conjugate lines, submanifolds on the Grassmannians, different aspects of the normalization problems for submanifolds (with special emphasis given to a connection in the normal bundle) and the problem of algebraizability for different kinds of submanifolds, the geometry of hypersurfaces and hyperbands, etc. A series of special types of submanifolds with special projective structures are s

  6. An invitation to noncommutative geometry

    CERN Document Server

    Marcolli, Matilde

    2008-01-01

    This is the first existing volume that collects lectures on this important and fast developing subject in mathematics. The lectures are given by leading experts in the field and the range of topics is kept as broad as possible by including both the algebraic and the differential aspects of noncommutative geometry as well as recent applications to theoretical physics and number theory. Sample Chapter(s). A Walk in the Noncommutative Garden (1,639 KB). Contents: A Walk in the Noncommutative Garden (A Connes & M Marcolli); Renormalization of Noncommutative Quantum Field Theory (H Grosse & R Wulke

  7. Projective geometry and projective metrics

    CERN Document Server

    Busemann, Herbert

    2005-01-01

    The basic results and methods of projective and non-Euclidean geometry are indispensable for the geometer, and this book--different in content, methods, and point of view from traditional texts--attempts to emphasize that fact. Results of special theorems are discussed in detail only when they are needed to develop a feeling for the subject or when they illustrate a general method. On the other hand, an unusual amount of space is devoted to the discussion of the fundamental concepts of distance, motion, area, and perpendicularity.Topics include the projective plane, polarities and conic sectio

  8. Number Theory, Analysis and Geometry

    CERN Document Server

    Goldfeld, Dorian; Jones, Peter

    2012-01-01

    Serge Lang was an iconic figure in mathematics, both for his own important work and for the indelible impact he left on the field of mathematics, on his students, and on his colleagues. Over the course of his career, Lang traversed a tremendous amount of mathematical ground. As he moved from subject to subject, he found analogies that led to important questions in such areas as number theory, arithmetic geometry, and the theory of negatively curved spaces. Lang's conjectures will keep many mathematicians occupied far into the future. In the spirit of Lang's vast contribution to mathematics, th

  9. Clustering in Hilbert simplex geometry

    KAUST Repository

    Nielsen, Frank

    2017-04-03

    Clustering categorical distributions in the probability simplex is a fundamental primitive often met in applications dealing with histograms or mixtures of multinomials. Traditionally, the differential-geometric structure of the probability simplex has been used either by (i) setting the Riemannian metric tensor to the Fisher information matrix of the categorical distributions, or (ii) defining the information-geometric structure induced by a smooth dissimilarity measure, called a divergence. In this paper, we introduce a novel computationally-friendly non-Riemannian framework for modeling the probability simplex: Hilbert simplex geometry. We discuss the pros and cons of those three statistical modelings, and compare them experimentally for clustering tasks.

  10. Exceptional geometry and Borcherds superalgebras

    Energy Technology Data Exchange (ETDEWEB)

    Palmkvist, Jakob [Mitchell Institute for Fundamental Physics and Astronomy, Texas A& M University,College Station, TX 77843 (United States)

    2015-11-05

    We study generalized diffeomorphisms in exceptional geometry with U-duality group E{sub n(n)} from an algebraic point of view. By extending the Lie algebra e{sub n} to an infinite-dimensional Borcherds superalgebra, involving also the extension to e{sub n+1}, the generalized Lie derivatives can be expressed in a simple way, and the expressions take the same form for any n≤7. The closure of the transformations then follows from the Jacobi identity and the grading of e{sub n+1} with respect to e{sub n}.

  11. Exceptional geometry and Borcherds superalgebras

    Science.gov (United States)

    Palmkvist, Jakob

    2015-11-01

    We study generalized diffeomorphisms in exceptional geometry with U-duality group E n( n) from an algebraic point of view. By extending the Lie algebra {e}_n to an infinite-dimensional Borcherds superalgebra, involving also the extension to {e}_{n+1} , the generalized Lie derivatives can be expressed in a simple way, and the expressions take the same form for any n ≤ 7. The closure of the transformations then follows from the Jacobi identity and the grading of {e}_{n+1} with respect to {e}_n.

  12. Stochastic geometry for image analysis

    CERN Document Server

    Descombes, Xavier

    2013-01-01

    This book develops the stochastic geometry framework for image analysis purpose. Two main frameworks are  described: marked point process and random closed sets models. We derive the main issues for defining an appropriate model. The algorithms for sampling and optimizing the models as well as for estimating parameters are reviewed.  Numerous applications, covering remote sensing images, biological and medical imaging, are detailed.  This book provides all the necessary tools for developing an image analysis application based on modern stochastic modeling.

  13. Evaluation of the effect of using electrosurgery in pulpectomy of deciduous teeth on succedaneous teeth: an animal study.

    Science.gov (United States)

    Sahebalam, Rasoul; Sarraf, Alireza; Abdollahi, Mojtaba; Jafarzadeh, Hamid; Rajati, Hamidreza; Patil, Shankargouda

    2015-03-01

    The aim of this study was to determine the probable side effects of electrosurgery in pulpectomy of deciduous teeth on succedaneous teeth in dogs. In this animal study, all maxillary and mandibular teeth at one side of five puppies' mouths were treated employing electrosurgical pulpectomy and were then compared with those of the other side treated using the conventional method. The electrosurgical dental electrode was placed in canals to the point of working length for the experimental group. After pulpectomy, the canals were filled with zinc oxide eugenol paste and the access cavity was restored with amalgam. The dogs remained under care until their successor teeth erupted and clinical examination was performed. The teeth treated employing electrosurgical pulpectomy presented natural appearance with no observable defects including enamel hypoplasia, diffuse opacities of enamel, demarcated opacities, and enamel discoloration. Electrosurgical pulpectomy can be considered as an option for pulpectomy of deciduous teeth.

  14. Computational geometry algorithms and applications

    CERN Document Server

    de Berg, Mark; Overmars, Mark; Schwarzkopf, Otfried

    1997-01-01

    Computational geometry emerged from the field of algorithms design and anal­ ysis in the late 1970s. It has grown into a recognized discipline with its own journals, conferences, and a large community of active researchers. The suc­ cess of the field as a research discipline can on the one hand be explained from the beauty of the problems studied and the solutions obtained, and, on the other hand, by the many application domains--computer graphics, geographic in­ formation systems (GIS), robotics, and others-in which geometric algorithms play a fundamental role. For many geometric problems the early algorithmic solutions were either slow or difficult to understand and implement. In recent years a number of new algorithmic techniques have been developed that improved and simplified many of the previous approaches. In this textbook we have tried to make these modem algorithmic solutions accessible to a large audience. The book has been written as a textbook for a course in computational geometry, but it can ...

  15. Fuzzy Logic for Incidence Geometry

    Science.gov (United States)

    2016-01-01

    The paper presents a mathematical framework for approximate geometric reasoning with extended objects in the context of Geography, in which all entities and their relationships are described by human language. These entities could be labelled by commonly used names of landmarks, water areas, and so forth. Unlike single points that are given in Cartesian coordinates, these geographic entities are extended in space and often loosely defined, but people easily perform spatial reasoning with extended geographic objects “as if they were points.” Unfortunately, up to date, geographic information systems (GIS) miss the capability of geometric reasoning with extended objects. The aim of the paper is to present a mathematical apparatus for approximate geometric reasoning with extended objects that is usable in GIS. In the paper we discuss the fuzzy logic (Aliev and Tserkovny, 2011) as a reasoning system for geometry of extended objects, as well as a basis for fuzzification of the axioms of incidence geometry. The same fuzzy logic was used for fuzzification of Euclid's first postulate. Fuzzy equivalence relation “extended lines sameness” is introduced. For its approximation we also utilize a fuzzy conditional inference, which is based on proposed fuzzy “degree of indiscernibility” and “discernibility measure” of extended points. PMID:27689133

  16. Entanglement classification with algebraic geometry

    Science.gov (United States)

    Sanz, M.; Braak, D.; Solano, E.; Egusquiza, I. L.

    2017-05-01

    We approach multipartite entanglement classification in the symmetric subspace in terms of algebraic geometry, its natural language. We show that the class of symmetric separable states has the structure of a Veronese variety and that its k-secant varieties are SLOCC invariants. Thus SLOCC classes gather naturally into families. This classification presents useful properties such as a linear growth of the number of families with the number of particles, and nesting, i.e. upward consistency of the classification. We attach physical meaning to this classification through the required interaction length of parent Hamiltonians. We show that the states W N and GHZ N are in the same secant family and that, effectively, the former can be obtained in a limit from the latter. This limit is understood in terms of tangents, leading to a refinement of the previous families. We compute explicitly the classification of symmetric states with N≤slant4 qubits in terms of both secant families and its refinement using tangents. This paves the way to further use of projective varieties in algebraic geometry to solve open problems in entanglement theory.

  17. Foundations of arithmetic differential geometry

    CERN Document Server

    Buium, Alexandru

    2017-01-01

    The aim of this book is to introduce and develop an arithmetic analogue of classical differential geometry. In this new geometry the ring of integers plays the role of a ring of functions on an infinite dimensional manifold. The role of coordinate functions on this manifold is played by the prime numbers. The role of partial derivatives of functions with respect to the coordinates is played by the Fermat quotients of integers with respect to the primes. The role of metrics is played by symmetric matrices with integer coefficients. The role of connections (respectively curvature) attached to metrics is played by certain adelic (respectively global) objects attached to the corresponding matrices. One of the main conclusions of the theory is that the spectrum of the integers is "intrinsically curved"; the study of this curvature is then the main task of the theory. The book follows, and builds upon, a series of recent research papers. A significant part of the material has never been published before.

  18. Clinical Manifestations of pathology of temporomandibular joints and masticatory muscles in patients with teeth occlusion and teeth row disturbances

    Directory of Open Access Journals (Sweden)

    A.V. Lepilin

    2010-06-01

    Full Text Available The aim of the research is a literature review about the problem of temporomandibular joints and masticatory muscles in patients with teeth occlusion and teeth row disturbances. Teeth occlusion and teeth row disturbances are widespread pathology of maxillofacial area, that can lead to different pathology alterations of masticatory system including musculo-articular dysfunction. Some specialists consider that the key factor of pathogenesis of musculo-articular dysfunction is occlusion disturbances, by the other opinion - discoordination of muscle contraction. Thus occlusive and muscular disorders are leading in pathogenesis and clinic of musculo-articular dysfunction

  19. Caring for children: little teeth, big challenges.

    Science.gov (United States)

    Rodd, H

    2012-04-13

    Dental care for young children with carious primary teeth may pose a number of challenges in terms of assessment and diagnosis, behaviour management and treatment planning. These challenges, together with some misconceptions about the value of restoring the primary dentition, have led to a reduction in the proportion of restorations provided for young children in primary care settings. The aim of my presentation at the forthcoming BDA conference is to provide an overview of current practices for caries management in young children. It will particularly focus on restorative interventions, including preformed metal crowns (using the Hall technique), and will consider the evidence-base for a variety of restorative options. In addition, the child's perspective of restorative care will be considered.

  20. Applying tribology to teeth of hoofed mammals.

    Science.gov (United States)

    Schulz, Ellen; Calandra, Ivan; Kaiser, Thomas M

    2010-01-01

    Mammals inhabit all types of environments and have evolved chewing systems capable of processing a huge variety of structurally diverse food components. Surface textures of cheek teeth should thus reflect the mechanisms of wear as well as the functional traits involved. We employed surface textures parameters from ISO/DIS 25178 and scale-sensitive fractal analysis (SSFA) to quantify dental wear in herbivorous mammals at the level of an individual wear enamel facet. We evaluated cheek dentitions of two grazing ungulates: the Blue Wildebeest (Connochaetes taurinus) and the Grevy's Zebra (Equus grevyi). Both inhabit the east African grassland savanna habitat, but they belong to fundamentally different taxonomic units. We tested the hypothesis that the foregut fermenting wildebeest and the hindgut fermenting zebra show functional traits in their dentitions that relate to their specific mode of food-composition processing and digestion. In general, surface texture parameters from SSFA as well as ISO/DIS 25178 indicated that individual enamel ridges acting as crushing blades and individual wear facets of upper cheek teeth are significantly different in surface textures in the zebra when compared with the wildebeest. We interpreted the complexity and anisotropy signals to be clearly related to the brittle, dry grass component in the diet of the zebra, unlike the wildebeest, which ingests a more heterogeneous diet including fresh grass and herbs. Thus, SSFA and ISO parameters allow distinctions within the subtle dietary strategies that evolved in herbivorous ungulates with fundamentally different systematic affinities but which exploit a similar dietary niche. © 2010 Wiley Periodicals, Inc.

  1. Conservative aesthetic techniques for discoloured teeth: 2. Microabrasion and composite.

    Science.gov (United States)

    Nixon, Peter J; Robinson, Stephen; Gahan Matthew; Chan, Martin F W Y

    2007-04-01

    The first article in this series discussed the minimal intervention approach to discoloured teeth, starting with dental bleaching. This second article goes on to explain the technique of microabrasion and the use of direct composite techniques. Microabrasion and composite can provide minimally invasive treatments for discoloured teeth.

  2. A VARIANT OF LAURENCE - MOON - BARDET - BIEDL SYNDROME SUPERNUMERARY TEETH

    OpenAIRE

    Arun Kumar; Ramesh; Yashaswini; Basavaraju; Mohan Kumar

    2014-01-01

    This family had a spectrum of many variants of Laurence moon bardet biedel syndrome in a single family , which had not been reported till date w here the affected family members had supernumerary teeth. Hence we propose a new syndrome complex in this family which is similar to Bardet biedl syndrome , but with added features of supernumerary teeth

  3. Utilization of Teeth Replacement Service Among the Elderly ...

    African Journals Online (AJOL)

    hanumantp

    Teeth play an important role in the maintenance of a positive self-image.[1] Replacement of lost teeth has been documented to be the most common reason for attendance in the prosthetic out-patient clinic of Lagos university teaching hospital (LUTH).[2,3] The adverse effect of tooth loss without replacement includes, drifting ...

  4. Teething myths among nursing mothers in a Nigerian community ...

    African Journals Online (AJOL)

    Background: Many symptoms had been associated with teething in children with the possibility of overlooking potentially fatal condition. Symptoms that had been associated with teething include diarrhoea, fever, vomiting and cough. The possibility that any of these symptoms could have been due to other causes call for ...

  5. The effects of impacted premaxillary supernumerary teeth on permanent incisors

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yun Hoa; Kim, Ji Yeon; Cho, Bong Hae [School of Dentistry, Pusan National University, Yangsan (Korea, Republic of)

    2016-12-15

    The aim of this study was to examine the radiographic features associated with impacted premaxillary supernumerary teeth, to determine the relationship between their characteristics and their effects on permanent incisors, and to investigate the types of orthodontic treatment that patients received after the extraction of impacted supernumerary teeth. The clinical records and radiographs of 193 patients whose impacted premaxillary supernumerary teeth were removed were retrospectively reviewed, and 241 impacted supernumerary teeth were examined. Cone-beam computed tomographic images and panoramic radiographs were examined to determine the number, location, sagittal position, orientation, and morphology of the supernumerary teeth. Their effects on permanent incisors and the orthodontic treatment received by patients after the extraction of the supernumeraries were also investigated. Supernumerary teeth were most frequently observed in the central incisor region, in the palatal position, in the inverted orientation, and were most commonly conical in shape. The most common complication was median diastema, followed by displacement and delayed eruption of the adjacent incisors. Ten (71.4%) of the 14 odontomas showed delayed eruption of the adjacent incisors. Displacement of the incisors was more frequently observed in association with supernumerary teeth with tuberculate or supplemental shapes. Orthodontic traction was most frequently performed after the removal of odontomas. In 32 cases (13.3%), permanent incisors erupted after the orthodontic creation of sufficient space. Median diastema was most common complication. The delayed eruption of incisors was common in supernumerary teeth with a vertical orientation and an odontoma shape.

  6. Modified Anchor Shaped Post Core Design for Primary Anterior Teeth

    Directory of Open Access Journals (Sweden)

    R. Rajesh

    2014-01-01

    Full Text Available Restoring severely damaged primary anterior teeth is challenging to pedodontist. Many materials are tried as a post core but each one of them has its own drawbacks. This a case report describing a technique to restore severely damaged primary anterior teeth with a modified anchor shaped post. This technique is not only simple and inexpensive but also produces better retention.

  7. Patterns of bone loss around teeth restored with endodontic posts

    NARCIS (Netherlands)

    Katsamakis, S.; Timmerman, M.; van der Velden, U.; de Cleen, M.; van der Weijden, F.

    2009-01-01

    Objectives: This retrospective study described the pattern of bone loss around teeth with endodontic posts in periodontitis patients, and compared it with contra-lateral teeth without posts. Material and Methods: From full-mouth radiographic surveys of 146 periodontitis patients (35 years), 194

  8. The effects of impacted premaxillary supernumerary teeth on permanent incisors.

    Science.gov (United States)

    Jung, Yun-Hoa; Kim, Ji-Yeon; Cho, Bong-Hae

    2016-12-01

    The aim of this study was to examine the radiographic features associated with impacted premaxillary supernumerary teeth, to determine the relationship between their characteristics and their effects on permanent incisors, and to investigate the types of orthodontic treatment that patients received after the extraction of impacted supernumerary teeth. The clinical records and radiographs of 193 patients whose impacted premaxillary supernumerary teeth were removed were retrospectively reviewed, and 241 impacted supernumerary teeth were examined. Cone-beam computed tomographic images and panoramic radiographs were examined to determine the number, location, sagittal position, orientation, and morphology of the supernumerary teeth. Their effects on permanent incisors and the orthodontic treatment received by patients after the extraction of the supernumeraries were also investigated. Supernumerary teeth were most frequently observed in the central incisor region, in the palatal position, in the inverted orientation, and were most commonly conical in shape. The most common complication was median diastema, followed by displacement and delayed eruption of the adjacent incisors. Ten (71.4%) of the 14 odontomas showed delayed eruption of the adjacent incisors. Displacement of the incisors was more frequently observed in association with supernumerary teeth with tuberculate or supplemental shapes. Orthodontic traction was most frequently performed after the removal of odontomas. In 32 cases (13.3%), permanent incisors erupted after the orthodontic creation of sufficient space. Median diastema was most common complication. The delayed eruption of incisors was common in supernumerary teeth with a vertical orientation and an odontoma shape.

  9. supernumerary teeth, polimorfisme gen vitamin D reseptor (VDR)

    OpenAIRE

    ASMAWATI

    2014-01-01

    Latar Belakang: Anomali gigi supernumerary teeth adalah kelainan bentuk dan jumlah gigi yang dapat menyebabkan masalah maloklusi, menganggu estetik dan deviasi ordinat gigi. Pada kondisi yang tidak erupsi dapat menyebabkan ameloblastoma dan odontogenic neoplasma. Adanya dugaan kuat faktor herediter sebagai penyebab terjadinya sehingga memerlukan penelitian genetik molekuler untuk membuktikan faktor genetik sebagai faktor risiko terjadinya supernumerary teeth,sehingga meningkatkan optimalisa...

  10. Does incomplete caries removal reduce strength of restored teeth?

    NARCIS (Netherlands)

    Hevinga, M.; Opdam, N.J.M.; Frencken, J.E.F.M.; Truin, G.J.; Huysmans, M.C.D.N.J.M.

    2010-01-01

    Little information is available about whether the presence of residual caries beneath an occlusal restoration affects fracture strength of the tooth. This in vitro study tested the hypothesis that restored teeth after incomplete excavation have lower fracture strengths than restored teeth after

  11. Knowledge and Practice of Pulp Therapy in Deciduous Teeth ...

    African Journals Online (AJOL)

    and stainless steel crowns were the materials of choice for final restoration of endodontically treated deciduous teeth. All 50 answered in the affirmative when asked if they would like to have additional information about pulp therapy in deciduous teeth. Conclusion: The study concluded that general dentists were regularly ...

  12. Diagnosis and clinical management of teeth with vertical root ...

    African Journals Online (AJOL)

    Even though VRF are commoner in endodontically treated teeth, its occurrence in non-restored teeth has been described. Clinical signs and symptoms vary according to the position of the fracture, tooth type, duration after fracture, periodontal condition of the tooth and architecture of the bone adjacent to the fracture.

  13. Surgically facilitated experimental movement of teeth : systematic review

    NARCIS (Netherlands)

    Liem, A. M. L.; Hoogeveen, E. J.; Jansma, J.; Ren, Y.

    Several surgical techniques based on corticotomy and dental distraction have been developed to improve the movement of teeth and reduce the duration of orthodontic treatment. In this systematic review we have critically assessed published studies on the experimental movement of teeth to find out

  14. Analysis of Fractured Teeth Utilizing Digital Microscopy: A Pilot Study

    Science.gov (United States)

    2016-06-01

    dentistry . This is due to longevity of life and ability to maintain natural dentition longer, supporting an increase in the number of fractured teeth...method for producing experimental simple vertical root fractures in dog teeth. J Endod 1993;19:512-5. 17. Bornstein MM, Wölner-Hanssen AB, Sendi P

  15. Replantation of Avulsed Permanent Anterior Teeth: A case report ...

    African Journals Online (AJOL)

    Tooth avulsion in the permanent dentition constitutes a dental emergency. Replantation of the avulsed tooth restores aesthetics and occlusal function shortly after the injury. This article describes the management of a 13-year old male with four avulsed anterior maxillary permanent teeth. The avulsed teeth were replanted ...

  16. Assessment of the periapical health of abutment teeth: A ...

    African Journals Online (AJOL)

    Key words: Abutment teeth, apical periodontitis, endodontics, epidemiology, radiology. Date of Acceptance: 29‑Nov‑2014. Introduction. Extensive removal of enamel and dentin is required during the preparation of teeth for fixed partial dentures. This procedure may lead to irreversible damage of the dental pulp if not carried ...

  17. Diabetes or Hypertension as Risk Indicators for Missing Teeth ...

    African Journals Online (AJOL)

    2018-02-07

    Feb 7, 2018 ... Oral diseases such as caries and chronic periodontitis are considerable public health problems worldwide because they affect a large proportion of the population; the ultimate outcome of those two epidemiologically important diseases is often the loss of affected teeth. Missing teeth reflect the history of ...

  18. Size variation in samples of fossil and recent murid teeth

    NARCIS (Netherlands)

    Freudenthal, M.; Martín Suárez, E.

    1990-01-01

    The variability coefficient proposed by Freudenthal & Cuenca Bescós (1984) for samples of fossil cricetid teeth, is calculated for about 200 samples of fossil and recent murid teeth. The results are discussed, and compared with those obtained for the Cricetidae.

  19. ELECTRIC PULP TEST OF TEETH WITH PERIODONTAL DISEASE.

    Directory of Open Access Journals (Sweden)

    Tsonko Uzunov

    2014-10-01

    Full Text Available Purpose: The aim of the research is to investigate the change in pulp vitality of teeth with periodontal disease using electric pulp tester (EPT. Methods: Subjected to observation were 108 patients with chronic periodontitis. Vitality of 805 teeth with periodontal pocket depth greater than 4 mm was studied by EPT. The research was conducted with EPT "Yonovit ". Results: The highest percentage of surveyed teeth (68.4% respond to the norm when they are tested with EPT – values between 3 μA and 10 μA . Teeth that respond to EPT with values ​​below 3 μA and between 35-100 μA are relatively equal - respectively 4.3% and 3.3%. With increased threshold of irritation – 10-35 μA react 23.4% of teeth. Small number of teeth have threshold of irritation over 100 μA - 0.6%. Conclusion: The value of EPT among periodontal damaged teeth depends on many factors - patient's age, extent of periodontal affect, group affiliation of teeth, etc.

  20. Prevalence of retained primary teeth among children with anterior ...

    African Journals Online (AJOL)

    Conclusion: This study revealed a high predominance of retained primary teeth amongst Orthodontic patients with anterior arch crowding in Benin City. This baseline information will aid in diagnosis, prevention, interception and management of anterior arch crowding in children due to prolonged retention of primary teeth.

  1. Rare occurrence of bilaterally impacted mandibular supernumerary teeth

    Directory of Open Access Journals (Sweden)

    Vinay Kumar Bhardwaj

    2012-01-01

    Full Text Available Introduction: Supernumerary teeth are present in addition to the normal complement of teeth in permanent or deciduous dentitions. Incidence is high in permanent dentition, affects both the gender. They are more common in males, with the male to female ratio of 2:1. When the supernumerary teeth are causing problems such as, extensive resorption of adjacent teeth, hindering the eruption or malposition of permanent teeth, early surgical intervention is recommended. Case Report: A case of bilaterally impacted supernumerary premolars was reported when an orthopentomograph view was taken which revealed the presence of additional teeth impacted in relation to 35-36 and 45-46. Surgical removal was done as they were resorbing the roots of teeth in their vicinity. Discussion: Literature reports increased occurrence of the supernumeraries in the maxilla but supernumerary premolars are more likely to develop in the mandible. Etiology of supernumerary teeth is ambiguous and is due to following conditions:atavism or reversion, heredity, aberrations during embryologic formation, progress zone, and unified etiologic explanation.

  2. Tuberculate Supernumerary Teeth: Report of A Case Showing ...

    African Journals Online (AJOL)

    Tuberculate supernumerary teeth are found in the maxillary anterior region. They usually result in oral problems such as malocclusion, food impaction, poor aesthetics and cyst formation. There is paucity of literature on this anomaly in our environment. This paper describes a case of tuberculate supernumerary teeth with ...

  3. Supernumerary primary teeth and the clinical significance: a report ...

    African Journals Online (AJOL)

    Supernumerary teeth occur frequently in the permanent dentition but they are rare in the primary dentition. Supernumerary teeth in the primary dentition usually erupt normally and are frequently of the supplemental type. The issue of differentiating the supplemental tooth from the normal series requires careful consideration.

  4. Resistance to cyclic loading of teeth restored with posts

    DEFF Research Database (Denmark)

    Sahafi, A; Peutzfeldt, A; Ravnholt, G

    2005-01-01

    This in vitro study evaluated the effect of presence of post, presence of core, and of shape, type, and surface treatment of posts on resistance to cyclic loading of crowned human teeth. For all teeth, crowns designed without ferrule were cast in sterling silver and luted with resin cement (Panavia...

  5. Extrication of DNA from Burnt Teeth Exposed to Environment.

    Science.gov (United States)

    Ramlal, Gantala; Vevaraju, Devarajn; Vemula, Arjun Yadav; Swapna, Tipirisety; Bindu, P Hima

    2017-08-01

    Teeth are good sources of DNA in mass disasters especially in fires and explosions because they are largely protected from environmental and physical conditions. It is possible to obtain mitochondrial DNA (mtDNA) even in cases of degraded human remains. To obtain DNA from burnt teeth exposed to environment for a period of six months and 12 months and to highlight the importance of DNA obtained from tooth in identifying a deceased in fire accidents after being subjected to environment. Randomly 20 extracted teeth samples were collected. The teeth were divided into two groups (Group 1 and 2) and were subjected to 700°C using a Delta burnout furnace. Burnt teeth were exposed to environment for a period of six months and 12 months respectively. Data was analysed by Statistical Package for Social Sciences (SPSS) version 16.0. Data was summarized by percentages for count data. The comparison within group was done by single proportion test and the comparison between two groups was done by two proportion test. All p-value less than 0.05 were considered as statistically significant. The present study revealed that mtDNA was obtained from eight extracted teeth samples among Group 1 and six extracted teeth samples among Group 2. Teeth are good source of DNA, even in cases where the bodies are burnt and exposed to environment.

  6. Some Progress in Conformal Geometry

    Directory of Open Access Journals (Sweden)

    Sun-Yung A. Chang

    2007-12-01

    Full Text Available This is a survey paper of our current research on the theory of partial differential equations in conformal geometry. Our intention is to describe some of our current works in a rather brief and expository fashion. We are not giving a comprehensive survey on the subject and references cited here are not intended to be complete. We introduce a bubble tree structure to study the degeneration of a class of Yamabe metrics on Bach flat manifolds satisfying some global conformal bounds on compact manifolds of dimension 4. As applications, we establish a gap theorem, a finiteness theorem for diffeomorphism type for this class, and diameter bound of the $sigma_2$-metrics in a class of conformal 4-manifolds. For conformally compact Einstein metrics we introduce an eigenfunction compactification. As a consequence we obtain some topological constraints in terms of renormalized volumes.

  7. Kinematic dynamos in spheroidal geometries

    Science.gov (United States)

    Ivers, D. J.

    2017-10-01

    The kinematic dynamo problem is solved numerically for a spheroidal conducting fluid of possibly large aspect ratio with an insulating exterior. The solution method uses solenoidal representations of the magnetic field and the velocity by spheroidal toroidal and poloidal fields in a non-orthogonal coordinate system. Scaling of coordinates and fields to a spherical geometry leads to a modified form of the kinematic dynamo problem with a geometric anisotropic diffusion and an anisotropic current-free condition in the exterior, which is solved explicitly. The scaling allows the use of well-developed spherical harmonic techniques in angle. Dynamo solutions are found for three axisymmetric flows in oblate spheroids with semi-axis ratios 1≤a/c≤25. For larger aspect ratios strong magnetic fields may occur in any region of the spheroid, depending on the flow, but the external fields for all three flows are weak and concentrated near the axis or periphery of the spheroid.

  8. Applied geometry and discrete mathematics

    CERN Document Server

    Sturm; Gritzmann, Peter; Sturmfels, Bernd

    1991-01-01

    This volume, published jointly with the Association for Computing Machinery, comprises a collection of research articles celebrating the occasion of Victor Klee's sixty-fifth birthday in September 1990. During his long career, Klee has made contributions to a wide variety of areas, such as discrete and computational geometry, convexity, combinatorics, graph theory, functional analysis, mathematical programming and optimization, and theoretical computer science. In addition, Klee made important contributions to mathematics education, mathematical methods in economics and the decision sciences, applications of discrete mathematics in the biological and social sciences, and the transfer of knowledge from applied mathematics to industry. In honor of Klee's achievements, this volume presents more than forty papers on topics related to Klee's research. While the majority of the papers are research articles, a number of survey articles are also included. Mirroring the breadth of Klee's mathematical contributions, th...

  9. Hue geometry and horizontal connections.

    Science.gov (United States)

    Ben-Shahar, Ohad; Zucker, Steven W

    2004-01-01

    Primate visual systems support an elaborate specialization for processing color information. Concentrating on the hue component, we observe that, contrary to Mondrian-like assumptions, hue varies in a smooth manner for ecologically important natural imagery. To represent these smooth variations, and to support those information processing tasks that utilize hue, a piecewise smooth hue field is postulated. The geometry of hue-patch interactions is developed analogously to orientation-patch interactions in texture. The result is a model for long-range (horizontal) interactions in the color domain, the power of which is demonstrated on a number of examples. Implications for computer image processing, computer vision, visual neurophysiology and psychophysics are discussed.

  10. Spinors in Physics and Geometry

    Science.gov (United States)

    Trautman, A.; Furlan, G.

    1988-11-01

    The Table of Contents for the full book PDF is as follows: * Preface * Killing Spinors According to O. Hijazi and Applications * Self-Duality Conditions Satisfied by the Spin Connections on Spheres * Maslov Index and Half - Forms * Spin - 3/2 Fields on Black Hole Spacetimes * Indecomposable Conformal Spinors and Operator Product Expansions in a Massless QED Model * Nonlinear Spinor Representations * Nonlinear Wave Equations for Intrinsic Spinor Coordinates * Twistors - "Spinors" of SU(2,2), Their Generalizations and Achievements * Spinors, Reflections and Clifford Algebras: A Review * overline {SL}(n, R) Spinors for Particles, Gravity and Superstrings * Spinors on Compact Riemann Surfaces * Simple Spinors as Urfelder * Applications of Cartan Spinors to Differential Geometry in Higher Dimensions * Killing Spinors on Spheres and Projective Spaces * Spinor Structures on Homogeneous Riemannian Spaces * Classical Strings and Minimal Surfaces * Representing Spinors with Differential Forms * Inequalities for Spinors Norms in Clifford Algebras * The Importance of Spin * The Theory of World Spinors * Final List of Participants

  11. The geometry of dynamical triangulations

    CERN Document Server

    Ambjørn, Jan; Marzuoli, Annalisa

    1997-01-01

    We discuss the geometry of dynamical triangulations associated with 3-dimensional and 4-dimensional simplicial quantum gravity. We provide analytical expressions for the canonical partition function in both cases, and study its large volume behavior. In the space of the coupling constants of the theory, we characterize the infinite volume line and the associated critical points. The results of this analysis are found to be in excellent agreement with the MonteCarlo simulations of simplicial quantum gravity. In particular, we provide an analytical proof that simply-connected dynamically triangulated 4-manifolds undergo a higher order phase transition at a value of the inverse gravitational coupling given by 1.387, and that the nature of this transition can be concealed by a bystable behavior. A similar analysis in the 3-dimensional case characterizes a value of the critical coupling (3.845) at which hysteresis effects are present.

  12. Conformal geometry and quasiregular mappings

    CERN Document Server

    Vuorinen, Matti

    1988-01-01

    This book is an introduction to the theory of spatial quasiregular mappings intended for the uninitiated reader. At the same time the book also addresses specialists in classical analysis and, in particular, geometric function theory. The text leads the reader to the frontier of current research and covers some most recent developments in the subject, previously scatterd through the literature. A major role in this monograph is played by certain conformal invariants which are solutions of extremal problems related to extremal lengths of curve families. These invariants are then applied to prove sharp distortion theorems for quasiregular mappings. One of these extremal problems of conformal geometry generalizes a classical two-dimensional problem of O. Teichmüller. The novel feature of the exposition is the way in which conformal invariants are applied and the sharp results obtained should be of considerable interest even in the two-dimensional particular case. This book combines the features of a textbook an...

  13. Dialogues about geometry and light

    CERN Document Server

    Bermudez, David; Leonhardt, Ulf

    2015-01-01

    Throughout human history, people have used sight to learn about the world, but only in relatively recent times the science of light has been developed. Egyptians and Mesopotamians made the first known lenses out of quartz, giving birth to what was later known as optics. On the other hand, geometry is a branch of mathematics that was born from practical studies concerning lengths, areas and volumes in the early cultures, although it was not put into axiomatic form until the 3rd century BC. In this work, we will discuss the connection between these two timeless topics and show some new things in old things". There has been several works in this direction, but taking into account the didactic approach of the Enrico Fermi Summer School, we would like to address the subject and our audience in a new light.

  14. Integrable systems, geometry, and topology

    CERN Document Server

    Terng, Chuu-Lian

    2006-01-01

    The articles in this volume are based on lectures from a program on integrable systems and differential geometry held at Taiwan's National Center for Theoretical Sciences. As is well-known, for many soliton equations, the solutions have interpretations as differential geometric objects, and thereby techniques of soliton equations have been successfully applied to the study of geometric problems. The article by Burstall gives a beautiful exposition on isothermic surfaces and their relations to integrable systems, and the two articles by Guest give an introduction to quantum cohomology, carry out explicit computations of the quantum cohomology of flag manifolds and Hirzebruch surfaces, and give a survey of Givental's quantum differential equations. The article by Heintze, Liu, and Olmos is on the theory of isoparametric submanifolds in an arbitrary Riemannian manifold, which is related to the n-wave equation when the ambient manifold is Euclidean. Mukai-Hidano and Ohnita present a survey on the moduli space of ...

  15. Noncommutative geometry of multicore bions

    Science.gov (United States)

    Karczmarek, Joanna L.; Sibilia, Ariel

    2013-01-01

    We find new BPS solutions to the nonabelian theory on a world-volume of parallel D1-branes. Our solutions describe two parallel, separated bundles of N D1-branes expanding out to form a single orthogonal D3-brane. This configuration corresponds to two charge N magnetic monopoles in the world-volume of a single D3-brane, deforming the D3-brane into two parallel spikes. We obtain the emergent surface corresponding to our nonabelian D1-brane configuration and demonstrate, at finite N , a surprisingly accurate agreement with the shape of the D3-brane world-volume as obtained from the abelian Born-Infeld action. Our solution provides an explicit realization of topology change in noncommutative geometry at finite N.

  16. Digital breast tomosynthesis geometry calibration

    Science.gov (United States)

    Wang, Xinying; Mainprize, James G.; Kempston, Michael P.; Mawdsley, Gordon E.; Yaffe, Martin J.

    2007-03-01

    Digital Breast Tomosynthesis (DBT) is a 3D x-ray technique for imaging the breast. The x-ray tube, mounted on a gantry, moves in an arc over a limited angular range around the breast while 7-15 images are acquired over a period of a few seconds. A reconstruction algorithm is used to create a 3D volume dataset from the projection images. This procedure reduces the effects of tissue superposition, often responsible for degrading the quality of projection mammograms. This may help improve sensitivity of cancer detection, while reducing the number of false positive results. For DBT, images are acquired at a set of gantry rotation angles. The image reconstruction process requires several geometrical factors associated with image acquisition to be known accurately, however, vibration, encoder inaccuracy, the effects of gravity on the gantry arm and manufacturing tolerances can produce deviations from the desired acquisition geometry. Unlike cone-beam CT, in which a complete dataset is acquired (500+ projections over 180°), tomosynthesis reconstruction is challenging in that the angular range is narrow (typically from 20°-45°) and there are fewer projection images (~7-15). With such a limited dataset, reconstruction is very sensitive to geometric alignment. Uncertainties in factors such as detector tilt, gantry angle, focal spot location, source-detector distance and source-pivot distance can produce several artifacts in the reconstructed volume. To accurately and efficiently calculate the location and angles of orientation of critical components of the system in DBT geometry, a suitable phantom is required. We have designed a calibration phantom for tomosynthesis and developed software for accurate measurement of the geometric parameters of a DBT system. These have been tested both by simulation and experiment. We will present estimates of the precision available with this technique for a prototype DBT system.

  17. Non-syndromic multiple supernumerary teeth: a rare entity.

    Science.gov (United States)

    Agrawal, Jiwanasha Manish; Agrawal, Manish Suresh; Nanjannawar, Lalita Girish; Adaki, Raghavendra Vithalappa

    2013-01-10

    Hyperdontia or supernumerary teeth without associated syndromes is a rare phenomenon, as supernumerary teeth are usually associated with cleft lip and palate or other syndromes such as Gardeners syndrome, cleidocranial dysplasia, trichorhinophalangic syndrome, etc. A 15-year-old girl reported for orthodontic treatment with a chief complaint of irregular teeth and unaesthetic smile. On examination class I malocclusion with severe crowding of upper anteriors, anterior open bite of 5 mm, cross bite with upper right posteriors, upper midline shift to right by 5 mm and two supernumerary teeth placed buccally in between 16 & 17 and 26 & 27, respectively, were found. On routine radiographical examination, two additional impacted supernumerary teeth were noticed distal to 18 and in mandibular arch in between roots of 35 and 36. A general physician was consulted who confirmed that there was no associated syndrome. Family history did not reveal any positive findings.

  18. Esthetic rehabilitation of discolored anterior teeth with porcelain veneers

    Science.gov (United States)

    Kamble, Vaibhav D.; Parkhedkar, Rambhau D.

    2013-01-01

    The common man is bombarded by the media extolling the virtues of “the perfect smile.” In the 21st century of esthetic dentistry, fractured, malformed, malposed, and discolored teeth can be changed and restored to highly desirable form due to introduction of wide range of esthetic materials and techniques. Porcelain veneers is a conservative method of restoring the appearance of discolored, pitted teeth, and teeth with diastemas that provide extremely good esthetic results. A 21-year-old female patient with staining in anterior teeth had reported to the Department of Prosthodontics for esthetic rehabilitation. The patient was treated with porcelain veneers on maxillary anterior teeth. The patient was satisfied with the enhanced esthetic appearance. PMID:23853471

  19. Esthetic rehabilitation of discolored anterior teeth with porcelain veneers

    Directory of Open Access Journals (Sweden)

    Vaibhav D Kamble

    2013-01-01

    Full Text Available The common man is bombarded by the media extolling the virtues of "the perfect smile." In the 21 st century of esthetic dentistry, fractured, malformed, malposed, and discolored teeth can be changed and restored to highly desirable form due to introduction of wide range of esthetic materials and techniques. Porcelain veneers is a conservative method of restoring the appearance of discolored, pitted teeth, and teeth with diastemas that provide extremely good esthetic results. A 21-year-old female patient with staining in anterior teeth had reported to the Department of Prosthodontics for esthetic rehabilitation. The patient was treated with porcelain veneers on maxillary anterior teeth. The patient was satisfied with the enhanced esthetic appearance.

  20. Stylolites, porosity, depositional texture, and silicates in chalk facies sediments

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke; Borre, Mai K.

    2007-01-01

    Comparison of chalk on the Ontong Java Plateau and chalk in the Central North Sea indicates that, whereas pressure dissolution is controlled by effective burial stress, pore-filling cementation is controlled by temperature. Effective burial stress is caused by the weight of all overlying water...... and sediments as counteracted by the pressure in the pore fluid, so the regional overpressure in the Central North Sea is one reason why the two localities have different relationships between temperature and effective burial stress. In the chalk of the Ontong Java Plateau the onset of calcite-silicate pressure...... equilibrated to quartz before the onset of pressure dissolution and thus, in this case, dissolution and precipitation of calcite have no lag. This temperature versus effective burial stress induced difference in diagenetic history is of particular relevance when exploring for hydrocarbons in normally pressured...

  1. A survey of natal and neonatal teeth in newborn infants.

    Science.gov (United States)

    Wang, Chun-Hsiang; Lin, Yai-Tin; Lin, Yng-Tzer J

    2017-03-01

    Since there is no comprehensive research of natal and neonatal teeth in Taiwan, careful investigation of natal or neonatal teeth is worthy of being studied. This retrospective study investigated the prevalence and clinical characteristics of natal or neonatal teeth in a hospital setting, and analyzed the possible relationships between investigated variables of the natal or neonatal teeth. All of the 12,019 infants born at an assigned hospital between January 1, 2008 and December 31, 2014 were investigated for natal or neonatal teeth. The identified individuals were reviewed for systemic diseases. Dental examinations included the location, clinical appearance, and degree of mobility. A positive family history of natal or neonatal teeth and mother's physical condition before delivery were also investigated. The collected data were analyzed using Fisher's exact test. Thirty infants were identified with a total of 43 natal or neonatal teeth (females, 19; males, 11). Most of the teeth were in the mandibular primary incisor position (97.6%). A radiographic examination confirmed that not all of the natal or neonatal teeth were supernumerary. No significant differences were observed between males and females in tooth morphology, positive family history, and treatment methods (p > 0.05) or between normal and conical shapes in positive family history, premature infant, mother's physical condition before delivery, and treatment methods (p > 0.05). Most of the natal or neonatal teeth were in the mandibular primary incisor position and not all of them were supernumerary. No gender differences were found in tooth morphology, positive family history, and treatment methods. The tooth morphology was not significantly related to a positive family history, premature delivery, or the mother's physical condition before delivery. Copyright © 2016. Published by Elsevier B.V.

  2. Bond strength test of acrylic artificial teeth with prosthetic base

    Directory of Open Access Journals (Sweden)

    Erna Kurnikasari

    2008-07-01

    Full Text Available Denture consists of acrylic artificial teeth and acrylic prothesis base bond chemically with a bond strength of 315 kgF/cm2. Most of the commercial acrylic artificial teeth do not specify their specifications and all of those acrylic artificial teeth do not include mechanical data (bond strength. The aim of this study is to discover which acrylic artificial teeth meet ADA specification no. 15. This study is a descriptive analytic study performed to 5 acrylic artificial teeth posterior brands commonly used by dentists and technicians. From each brand, 3 sample teeth were taken. The acrylic artificial teeth were prepared into a rectangular shape and were attached between acrylic prothesis base simulation and jigs. The sample was given tensile load using a Universal Testing Machine. The amount of force that causes the teeth to be fractured was recorded and the bond strength was calculated. The results of the study show that the average value for the five acrylic artificial teeth for the five brands were as followed: Brand A, 125.993 kgF/cm2; B, 188.457 kgF/cm2; C, 175.880 kgF/cm2; D, 153.373 kgF/cm2; E, 82.839 kgF/cm2. The data can be tested statistically by using One Way ANOVA test and Dunnett test (alpha = 0.05. From the study, it is concluded that the five acrylic artificial teeth have a bond strength below the ADA specification no. 15.

  3. N=1 Special Geometry, Mixed Hodge Variations and Toric Geometry

    CERN Document Server

    Lerche, Wolfgang; Warner, Nicholas P

    2002-01-01

    We study the superpotential of a certain class of N=1 supersymmetric type II compactifications with fluxes and D-branes. We show that it has an important two-dimensional meaning in terms of a chiral ring of the topologically twisted theory on the world-sheet. In the open-closed string B-model, this chiral ring is isomorphic to a certain relative cohomology group V, which is the appropriate mathematical concept to deal with both the open and closed string sectors. The family of mixed Hodge structures on V then implies for the superpotential to have a certain geometric structure. This structure represents a holomorphic, N=1 supersymmetric generalization of the well-known N=2 special geometry. It defines an integrable connection on the topological family of open-closed B-models, and a set of special coordinates on the space \\cal M of vev's in N=1 chiral multiplets. We show that it can be given a very concrete and simple realization for linear sigma models, which leads to a powerful and systematic method for comp...

  4. The ins and outs of the evolutionary origin of teeth.

    Science.gov (United States)

    Donoghue, Philip C J; Rücklin, Martin

    2016-01-01

    The role of teeth and jaws, as innovations that underpinned the evolutionary success of living jawed vertebrates, is well understood, but their evolutionary origins are less clear. The origin of teeth, in particular, is mired in controversy with competing hypotheses advocating their origin in external dermal denticles ("outside-in") versus a de novo independent origin ("inside-out"). No evidence has ever been presented demonstrating materially the traditional "outside-in" theory of teeth evolving from dermal denticles, besides circumstantial evidence of a commonality of structure and organogenesis, and phylogenetic evidence that dermal denticles appear earlier in vertebrate phylogeny that do teeth. Meanwhile, evidence has mounted in support of "inside-out" theory, through developmental studies that have indicated that endoderm is required for tooth development, and fossil studies that have shown that tooth-like structures evolved before dermal denticles (conodont dental elements), that tooth replacement evolving before teeth (thelodont pharyngeal denticles), and that teeth evolved many times independently through co-option of such structures. However, the foundations of "inside-out" theory have been undermined fatally by critical reanalysis of the evidence on which it was based. Specifically, it has been shown that teeth develop from dermal, endodermal or mixed epithelia and, therefore, developmental distinctions between teeth and dermal denticles are diminished. Furthermore the odontode-like structure of conodont elements has been shown to have evolved independently of dermal and internal odontodes. The tooth-like replacement encountered in thelodont pharyngeal odontodes has been shown to have evolved independently of teeth and tooth replacement and teeth have been shown to have evolved late within the gnathostome stem lineage indicating that it is probable, if not definitive, that teeth evolved just once in gnathostome evolution. Thus, the "inside-out" hypothesis

  5. Automorphisms in Birational and Affine Geometry

    CERN Document Server

    Ciliberto, Ciro; Flenner, Hubert; McKernan, James; Prokhorov, Yuri; Zaidenberg, Mikhail

    2014-01-01

    The main focus of this volume is on the problem of describing the automorphism groups of affine and projective varieties, a classical subject in algebraic geometry where, in both cases, the automorphism group is often infinite dimensional. The collection covers a wide range of topics and is intended for researchers in the fields of classical algebraic geometry and birational geometry (Cremona groups) as well as affine geometry with an emphasis on algebraic group actions and automorphism groups. It presents original research and surveys and provides a valuable overview of the current state of the art in these topics. Bringing together specialists from projective, birational algebraic geometry and affine and complex algebraic geometry, including Mori theory and algebraic group actions, this book is the result of ensuing talks and discussions from the conference “Groups of Automorphisms in Birational and Affine Geometry” held in October 2012, at the CIRM, Levico Terme, Italy. The talks at the conference high...

  6. Subsectors, Dynkin diagrams and new generalised geometries

    Science.gov (United States)

    Strickland-Constable, Charles

    2017-08-01

    We examine how generalised geometries can be associated with a labelled Dynkin diagram built around a gravity line. We present a series of new generalised geometries based on the groups Spin( d, d) × ℝ + for which the generalised tangent space transforms in a spinor representation of the group. In low dimensions these all appear in subsectors of maximal supergravity theories. The case d = 8 provides a geometry for eight-dimensional backgrounds of M theory with only seven-form flux, which have not been included in any previous geometric construction. This geometry is also one of a series of "half-exceptional" geometries, which "geometrise" a six-form gauge field. In the appendix, we consider exam-ples of other algebras appearing in gravitational theories and give a method to derive the Dynkin labels for the "section condition" in general. We argue that generalised geometry can describe restrictions and subsectors of many gravitational theories.

  7. Connections between algebra, combinatorics, and geometry

    CERN Document Server

    Sather-Wagstaff, Sean

    2014-01-01

    Commutative algebra, combinatorics, and algebraic geometry are thriving areas of mathematical research with a rich history of interaction. Connections Between Algebra, Combinatorics, and Geometry contains lecture notes, along with exercises and solutions, from the Workshop on Connections Between Algebra and Geometry held at the University of Regina from May 29-June 1, 2012. It also contains research and survey papers from academics invited to participate in the companion Special Session on Interactions Between Algebraic Geometry and Commutative Algebra, which was part of the CMS Summer Meeting at the University of Regina held June 2–3, 2012, and the meeting Further Connections Between Algebra and Geometry, which was held at the North Dakota State University, February 23, 2013. This volume highlights three mini-courses in the areas of commutative algebra and algebraic geometry: differential graded commutative algebra, secant varieties, and fat points and symbolic powers. It will serve as a useful resou...

  8. Accuracy assessment of high frequency 3D ultrasound for digital impression-taking of prepared teeth

    Science.gov (United States)

    Heger, Stefan; Vollborn, Thorsten; Tinschert, Joachim; Wolfart, Stefan; Radermacher, Klaus

    2013-03-01

    Silicone based impression-taking of prepared teeth followed by plaster casting is well-established but potentially less reliable, error-prone and inefficient, particularly in combination with emerging techniques like computer aided design and manufacturing (CAD/CAM) of dental prosthesis. Intra-oral optical scanners for digital impression-taking have been introduced but until now some drawbacks still exist. Because optical waves can hardly penetrate liquids or soft-tissues, sub-gingival preparations still need to be uncovered invasively prior to scanning. High frequency ultrasound (HFUS) based micro-scanning has been recently investigated as an alternative to optical intra-oral scanning. Ultrasound is less sensitive against oral fluids and in principal able to penetrate gingiva without invasively exposing of sub-gingival preparations. Nevertheless, spatial resolution as well as digitization accuracy of an ultrasound based micro-scanning system remains a critical parameter because the ultrasound wavelength in water-like media such as gingiva is typically smaller than that of optical waves. In this contribution, the in-vitro accuracy of ultrasound based micro-scanning for tooth geometry reconstruction is being investigated and compared to its extra-oral optical counterpart. In order to increase the spatial resolution of the system, 2nd harmonic frequencies from a mechanically driven focused single element transducer were separated and corresponding 3D surface models were calculated for both fundamentals and 2nd harmonics. Measurements on phantoms, model teeth and human teeth were carried out for evaluation of spatial resolution and surface detection accuracy. Comparison of optical and ultrasound digital impression taking indicate that, in terms of accuracy, ultrasound based tooth digitization can be an alternative for optical impression-taking.

  9. Classical geometry Euclidean, transformational, inversive, and projective

    CERN Document Server

    Leonard, I E; Liu, A C F; Tokarsky, G W

    2014-01-01

    Features the classical themes of geometry with plentiful applications in mathematics, education, engineering, and science Accessible and reader-friendly, Classical Geometry: Euclidean, Transformational, Inversive, and Projective introduces readers to a valuable discipline that is crucial to understanding bothspatial relationships and logical reasoning. Focusing on the development of geometric intuitionwhile avoiding the axiomatic method, a problem solving approach is encouraged throughout. The book is strategically divided into three sections: Part One focuses on Euclidean geometry, which p

  10. A vector space approach to geometry

    CERN Document Server

    Hausner, Melvin

    2010-01-01

    The effects of geometry and linear algebra on each other receive close attention in this examination of geometry's correlation with other branches of math and science. In-depth discussions include a review of systematic geometric motivations in vector space theory and matrix theory; the use of the center of mass in geometry, with an introduction to barycentric coordinates; axiomatic development of determinants in a chapter dealing with area and volume; and a careful consideration of the particle problem. 1965 edition.

  11. Applications of Affine and Weyl geometry

    CERN Document Server

    García-Río, Eduardo; Nikcevic, Stana

    2013-01-01

    Pseudo-Riemannian geometry is, to a large extent, the study of the Levi-Civita connection, which is the unique torsion-free connection compatible with the metric structure. There are, however, other affine connections which arise in different contexts, such as conformal geometry, contact structures, Weyl structures, and almost Hermitian geometry. In this book, we reverse this point of view and instead associate an auxiliary pseudo-Riemannian structure of neutral signature to certain affine connections and use this correspondence to study both geometries. We examine Walker structures, Riemannia

  12. Introduction to non-Euclidean geometry

    CERN Document Server

    Wolfe, Harold E

    2012-01-01

    One of the first college-level texts for elementary courses in non-Euclidean geometry, this concise, readable volume is geared toward students familiar with calculus. A full treatment of the historical background explores the centuries-long efforts to prove Euclid's parallel postulate and their triumphant conclusion. Numerous original exercises form an integral part of the book.Topics include hyperbolic plane geometry and hyperbolic plane trigonometry, applications of calculus to the solutions of some problems in hyperbolic geometry, elliptic plane geometry and trigonometry, and the consistenc

  13. A curriculum vitae of teeth: evolution, generation, regeneration.

    Science.gov (United States)

    Koussoulakou, Despina S; Margaritis, Lukas H; Koussoulakos, Stauros L

    2009-01-01

    The ancestor of recent vertebrate teeth was a tooth-like structure on the outer body surface of jawless fishes. Over the course of 500,000,000 years of evolution, many of those structures migrated into the mouth cavity. In addition, the total number of teeth per dentition generally decreased and teeth morphological complexity increased. Teeth form mainly on the jaws within the mouth cavity through mutual, delicate interactions between dental epithelium and oral ectomesenchyme. These interactions involve spatially restricted expression of several, teeth-related genes and the secretion of various transcription and signaling factors. Congenital disturbances in tooth formation, acquired dental diseases and odontogenic tumors affect millions of people and rank human oral pathology as the second most frequent clinical problem. On the basis of substantial experimental evidence and advances in bioengineering, many scientists strongly believe that a deep knowledge of the evolutionary relationships and the cellular and molecular mechanisms regulating the morphogenesis of a given tooth in its natural position, in vivo, will be useful in the near future to prevent and treat teeth pathologies and malformations and for in vitro and in vivo teeth tissue regeneration.

  14. Estimation of age from development and eruption of teeth.

    Science.gov (United States)

    Manjunatha, B S; Soni, Nishit K

    2014-05-01

    The developing dentition is used to assess maturity and estimate the age in many disciplines including anthropology, archeology, forensic science, pediatric dentistry and orthodontics. There is evidence that dental development is less effected than skeletal development by malnutrition and hormonal disorders. There are two methods of dental age assessment, radiographically and by clinically visualization of eruption of teeth. The clinical method to assess dental age is based on the emergence of teeth in the mouth. This method is more suitable since it does not require any special equipment, expertise and is more economical. Tooth formation is the best choice for estimating the age as variations are less as compared to other development factors. Eruption of teeth is one of the changes observed easily among the various dynamic changes that occur from the formation of teeth to the final shedding of teeth. The times of eruption of teeth are fairly constant and this can be made use of in ascertaining the average age of eruption of the tooth. Assessment of age of an individual by examination of teeth is one of the accepted methods of age determination.

  15. Maturation of teeth adjacent to dental agenesis site.

    Science.gov (United States)

    Ben-Bassat, Yocheved; Babadzhanov, Daniel; Brin, Ilana; Hazan-Molina, Hagai; Aizenbud, Dror

    2014-10-01

    The purpose of this study was to evaluate the developmental stage of teeth adjacent to the agenesis site in comparison to their antimeres. Panoramic views of 39 patients with unilateral dental agenesis and 42 normal controls were evaluated. The dental developmental stage (normal or delayed) of the teeth adjacent to the agenesis site was determined for each patient using the Haavikko's method, while the overall dental age was determined by Becker's method. No statistically significant difference was found in the developmental stage of teeth adjacent to the agenesis, compared to their antimere and to the same teeth in the normal control group. However, the prevalence of cases with no difference in development was almost double for the tooth distal to the agenesis site compared to the tooth mesial to the agenesis site in the hypodontia group (84.6% distal and 43.6% mesial; p teeth adjacent to the agenesis site and their antimeres. (2) Teeth mesial to the agenesis site showed some delay in development compared to teeth distal to the agenesis site, in this study. (3) The 1st molars, which were in most of the cases the distal adjacent tooth to the site of agenesis, showed developmental stability. (4) Additional longitudinal studies are needed to examine the dental developmental pattern in patients with agenesis.

  16. Management and outcome following extraction of 303 supernumerary teeth in pediatric patients.

    Science.gov (United States)

    Mínguez-Martinez, Ignacio; Ata-Ali, Javier; Bonet-Coloma, Cristina; Peñarrocha-Oltra, David; Peñarrocha-Diago, Maria A; Minguez-Sanz, Juan M

    2012-01-01

    The purpose of this study was to describe the treatment of permanent teeth impacted by supernumerary teeth and their outcome following extraction. The study population comprised 200 2- to 14-year-olds. A total of 303 supernumerary teeth were removed from the 200 patients. Surgery was performed on: 129 teeth (~43%) from the vestibular and palatine/lingual (mixed) side; 110 teeth (~36%) from the palatine/lingual side; and 64 teeth (~21%) from the vestibular side. Regarding the shape of the supernumerary teeth, the distribution was: 118 conoid teeth; 92 supplementary teeth; 66 tuberculate teeth; and 27 teeth of varied shapes. In approximately 61% of the permanent teeth (159 teeth), the supernumerary teeth caused impaction of the former, while no case of impaction was recorded in the case of the primary dentition. The impacted permanent teeth evolved favorably in 100% of the orthodontic tractions, in 80% of the relocations, and in approximately 65% of the conductive alveolectomies. The highest percentage success rate in treating permanent teeth impacted by supernumerary teeth corresponded to those cases in which surgery could be combined with orthodontic treatment. There were no displacements of neighboring buds during removal of the supernumerary teeth in the primary dentition.

  17. Topics in Cubic Special Geometry

    CERN Document Server

    Bellucci, Stefano; Roychowdhury, Raju

    2011-01-01

    We reconsider the sub-leading quantum perturbative corrections to N=2 cubic special Kaehler geometries. Imposing the invariance under axion-shifts, all such corrections (but the imaginary constant one) can be introduced or removed through suitable, lower unitriangular symplectic transformations, dubbed Peccei-Quinn (PQ) transformations. Since PQ transformations do not belong to the d=4 U-duality group G4, in symmetric cases they generally have a non-trivial action on the unique quartic invariant polynomial I4 of the charge representation R of G4. This leads to interesting phenomena in relation to theory of extremal black hole attractors; namely, the possibility to make transitions between different charge orbits of R, with corresponding change of the supersymmetry properties of the supported attractor solutions. Furthermore, a suitable action of PQ transformations can also set I4 to zero, or vice versa it can generate a non-vanishing I4: this corresponds to transitions between "large" and "small" charge orbit...

  18. Latent geometry of bipartite networks

    Science.gov (United States)

    Kitsak, Maksim; Papadopoulos, Fragkiskos; Krioukov, Dmitri

    2017-03-01

    Despite the abundance of bipartite networked systems, their organizing principles are less studied compared to unipartite networks. Bipartite networks are often analyzed after projecting them onto one of the two sets of nodes. As a result of the projection, nodes of the same set are linked together if they have at least one neighbor in common in the bipartite network. Even though these projections allow one to study bipartite networks using tools developed for unipartite networks, one-mode projections lead to significant loss of information and artificial inflation of the projected network with fully connected subgraphs. Here we pursue a different approach for analyzing bipartite systems that is based on the observation that such systems have a latent metric structure: network nodes are points in a latent metric space, while connections are more likely to form between nodes separated by shorter distances. This approach has been developed for unipartite networks, and relatively little is known about its applicability to bipartite systems. Here, we fully analyze a simple latent-geometric model of bipartite networks and show that this model explains the peculiar structural properties of many real bipartite systems, including the distributions of common neighbors and bipartite clustering. We also analyze the geometric information loss in one-mode projections in this model and propose an efficient method to infer the latent pairwise distances between nodes. Uncovering the latent geometry underlying real bipartite networks can find applications in diverse domains, ranging from constructing efficient recommender systems to understanding cell metabolism.

  19. The geometry of population genetics

    CERN Document Server

    Akin, Ethan

    1979-01-01

    The differential equations which model the action of selection and recombination are nonlinear equations which are impossible to It is even difficult to describe in general the solve explicitly. Recently, Shahshahani began using qualitative behavior of solutions. differential geometry to study these equations [28]. with this mono­ graph I hope to show that his ideas illuminate many aspects of pop­ ulation genetics. Among these are his proof and clarification of Fisher's Fundamental Theorem of Natural Selection and Kimura's Maximum Principle and also the effect of recombination on entropy. We also discover the relationship between two classic measures of 2 genetic distance: the x measure and the arc-cosine measure. There are two large applications. The first is a precise definition of the biological concept of degree of epistasis which applies to general (i.e. frequency dependent) forms of selection. The second is the unexpected appearance of cycling. We show that cycles can occur in the two-locus-two-allele...

  20. Linguistic geometry for technologies procurement

    Science.gov (United States)

    Stilman, Boris; Yakhnis, Vladimir; Umanskiy, Oleg; Boyd, Ron

    2005-05-01

    In the modern world of rapidly rising prices of new military hardware, the importance of Simulation Based Acquisition (SBA) is hard to overestimate. With SAB, DOD would be able to test, develop CONOPS for, debug, and evaluate new conceptual military equipment before actually building the expensive hardware. However, only recently powerful tools for real SBA have been developed. Linguistic Geometry (LG) permits full-scale modeling and evaluation of new military technologies, combinations of hardware systems and concepts of their application. Using LG tools, the analysts can create a gaming environment populated with the Blue forces armed with the new conceptual hardware as well as with appropriate existing weapons and equipment. This environment will also contain the intelligent enemy with appropriate weaponry and, if desired, with a conceptual counters to the new Blue weapons. Within such LG gaming environment, the analyst can run various what-ifs with the LG tools providing the simulated combatants with strategies and tactics solving their goals with minimal resources spent.

  1. Fractal Geometry and Stochastics V

    CERN Document Server

    Falconer, Kenneth; Zähle, Martina

    2015-01-01

    This book brings together leading contributions from the fifth conference on Fractal Geometry and Stochastics held in Tabarz, Germany, in March 2014. The book is divided into five sections covering different facets of this fast developing area: geometric measure theory, self-similar fractals and recurrent structures, analysis and algebra on fractals, multifractal theory, and random constructions. There are state-of-the-art surveys as well as papers highlighting more specific recent advances. The authors are world-experts who present their topics comprehensibly and attractively. The book provides an accessible gateway to the subject for newcomers as well as a reference for recent developments for specialists. Authors include: Krzysztof Barański, Julien Barral, Kenneth Falconer, De-Jun Feng, Peter J. Grabner, Rostislav Grigorchuk, Michael Hinz, Stéphane Jaffard, Maarit Järvenpää, Antti Käenmäki, Marc Kesseböhmer, Michel Lapidus, Klaus Mecke, Mark Pollicott,  Michał Rams, Pablo Shmerkin, and András Te...

  2. Tooth size patterns in patients with hypodontia and supernumerary teeth.

    Science.gov (United States)

    Brook, A H; Griffin, R C; Smith, R N; Townsend, G C; Kaur, G; Davis, G R; Fearne, J

    2009-12-01

    Anomalies of tooth number may not be isolated conditions but may have wider associations in the development of the dentition including tooth size. This study aimed to examine links between hypodontia, supernumerary teeth and crown size, considering the effect on the development of the whole dentition and so increase understanding of the aetiology of these conditions. The patients, who were all of European ancestry, were 60 young adults (30 males and 30 females) with hypodontia and 60 age and sex matched controls together with 60 young adults (39 males and 21 females) with supernumerary teeth and 60 age and sex matched controls. Hand measurements of mesiodistal and buccolingual dimensions were made of the teeth on dental study models using Mitutoyo electric callipers. The mean value of two measurements was used and intra-operator and inter-operator reliability determined. Patients with hypodontia had smaller teeth than the control group and this difference was statistically significant (pteeth except the MD dimensions of 13, 23, 24 and 44. The difference in size was greatest for the BL dimensions in hypodontia patients. Further, the greater the number of missing teeth the smaller the tooth size. The hypodontia patients also showed higher variability in tooth dimensions than the control group. Patients with supernumerary teeth had larger teeth than the controls, with the greatest differences in the MD dimensions. In both hypodontia and supernumerary patients the differences in tooth size were generalised throughout the dentition. In anomalies of tooth number the size of teeth is also involved. In patients with hypodontia and supernumerary teeth the crown size of the whole dentition is affected. These findings are compatible with a multifactorial aetiology of these conditions.

  3. Oral biofilm architecture on natural teeth.

    Directory of Open Access Journals (Sweden)

    Vincent Zijnge

    Full Text Available Periodontitis and caries are infectious diseases of the oral cavity in which oral biofilms play a causative role. Moreover, oral biofilms are widely studied as model systems for bacterial adhesion, biofilm development, and biofilm resistance to antibiotics, due to their widespread presence and accessibility. Despite descriptions of initial plaque formation on the tooth surface, studies on mature plaque and plaque structure below the gum are limited to landmark studies from the 1970s, without appreciating the breadth of microbial diversity in the plaque. We used fluorescent in situ hybridization to localize in vivo the most abundant species from different phyla and species associated with periodontitis on seven embedded teeth obtained from four different subjects. The data showed convincingly the dominance of Actinomyces sp., Tannerella forsythia, Fusobacterium nucleatum, Spirochaetes, and Synergistetes in subgingival plaque. The latter proved to be new with a possibly important role in host-pathogen interaction due to its localization in close proximity to immune cells. The present study identified for the first time in vivo that Lactobacillus sp. are the central cells of bacterial aggregates in subgingival plaque, and that Streptococcus sp. and the yeast Candida albicans form corncob structures in supragingival plaque. Finally, periodontal pathogens colonize already formed biofilms and form microcolonies therein. These in vivo observations on oral biofilms provide a clear vision on biofilm architecture and the spatial distribution of predominant species.

  4. Postpubertal nonfamilial cherubism and teeth transposition.

    Science.gov (United States)

    Ozan, Bora; Muğlali, Mehtap; Celenk, Peruze; Günhan, Omer

    2010-09-01

    Cherubism is a rare, nonneoplastic, fibro-osseous disease. It is an autosomal-dominant disorder in which the normal bone is replaced by cellular fibrous tissue and immature bone. It is genetically inherited, although many nonfamilial cases have been reported. Cherubism is a bone disease clinically characterized by bilateral, painless enlargements of the jaws. The mandible is the most severely affected craniofacial component, in which uncontrolled growth of the malady deteriorates the aesthetic balance of the face. A malocclusive and abnormal dentition, worse in the mandible, can be seen. Histopathologically, numerous randomly distributed multinucleated giant cells and vascular spaces within a fibrous connective tissue stroma with or without eosinophilic collagen perivascular cuffing were apparent. The appearance of the affected children is normal at birth. Between the ages of 2 and 7 years, swellings within the mandibular body or tuberosities of maxilla appear. This article relates to a postpubertal nonfamilial cherubism case that was noticed with multiple radiolucencies in radiographic examination and its effects on teeth.

  5. POST-MORTEM CHANGES IN TEETH- FORENSIC ISSUES

    Directory of Open Access Journals (Sweden)

    Irina MANOILESCU

    2015-12-01

    Full Text Available Teeth have an increased resistance to environmental factors and decomposition processes, which makes them highly valuable in forensic investigations. The either physical (wind, water, sun, soil type or biological (plant roots, insects, animals environmental factors and the decomposition processes induce post-mortem changes in teeth, which are relevant to forensic investigation in terms of estimating the post-mortem interval or of elucidating the conditions in which the body stood after death. In this paper, based on the data provided in the literature, the authors present the main changes induced by environmental factors and decomposition processes in teeth and refer to their relevance in forensic activity.

  6. Bilateral supernumerary teeth in deciduous dentition-a rarity.

    Science.gov (United States)

    Acharya, Sonu; Ghosh, Chiranjit; Mondal, Pradeep Kumar

    2014-05-01

    Supernumerary teeth are considered as one of the most significant dental anomalies during the primary and early mixed dentition stages. They are of great concern to the dentists and parents because of the eruption, occlusal, and esthetic problems they can cause. Supernumerary teeth occur more frequently in the permanent dentition but rarely in primary dentition and more often seen in males. A supernumerary tooth in the primary dentition can cause ectopic or delayed eruption of permanent central incisors which will further alter occlusion and may compromise esthetics and formation of dentigerous cysts. Here we discuss a case of bilateral supernumerary teeth in deciduous dentition in a female child.

  7. Real-Time Rendering of Teeth with No Preprocessing

    DEFF Research Database (Denmark)

    Larsen, Christian Thode; Frisvad, Jeppe Revall; Jensen, Peter Dahl Ejby

    2012-01-01

    We present a technique for real-time rendering of teeth with no need for computational or artistic preprocessing. Teeth constitute a translucent material consisting of several layers; a highly scattering material (dentine) beneath a semitransparent layer (enamel) with a transparent coating (saliva......). In this study we examine how light interacts with this multilayered structure. In the past, rendering of teeth has mostly been done using image-based texturing or volumetric scans. We work with surface scans and have therefore developed a simple way of estimating layer thicknesses. We use scattering properties...

  8. The Happy End of Tragic Story: Recycling of Avulsed Teeth

    Directory of Open Access Journals (Sweden)

    Zuhal Kırzıoğlu

    2016-08-01

    Full Text Available Recurrent traumatic injury to immature permanent teeth and environmental tissue may result in extraction of teeth. Due to the growing process of young patients is not completed, until the completion of this process and the fixed prosthesis is fabricated, space maintenance should be prepared for aesthetic and function. This case report presents the use of the clinical crown of failed teeth as the part of partial space maintenance and its beneficial effect on the patient who had multiply dental trauma many times from seven years of age.

  9. Treatment of avulsed teeth with Emdogain--a case report.

    Science.gov (United States)

    Caglar, Esber; Tanboga, Ilknur; Süsal, Seckin

    2005-02-01

    The present case report describes the reimplantation of avulsed teeth with the treatment of Emdogain. Case was avulsed right maxillary permanent central and lateral incisor in a 9-year-old girl suffering from a traumatic injury. After pretreatment of avulsed teeth, Emdogain was applied to the root surface and into the extraction socket with subsequent replantation of the tooth. Evaluation parameters included horizontal and vertical percussion sound and periapical radiographs. At 1-2-6-12-month follow-up period, the clinical and radiographic appearance of the teeth showed resolution of mobility and no signs of replacement resorbption.

  10. Comparison of Periodontal Ligament Stem Cells Isolated from the Periodontium of Healthy Teeth and Periodontitis-Affected Teeth

    Directory of Open Access Journals (Sweden)

    Sara Soheilifar

    2016-11-01

    Full Text Available Objectives: Stem cell (SC therapy is a promising technique for tissue regeneration. This study aimed to compare the viability and proliferation ability of periodontal ligament stem cells (PDLSCs isolated from the periodontium of healthy and periodontitis-affected teeth to obtain an autologous, easily accessible source of SCs for tissue regeneration in periodontitis patients.Materials and Methods: The PDLSCs were isolated from the roots of clinically healthy premolars extracted for orthodontic purposes and periodontally involved teeth with hopeless prognosis (with and without phase I periodontal treatment. Cells were cultured and viability and proliferation ability of third passage cells in each group were evaluated using the methyl thiazol tetrazolium assay. The results were statistically analyzed using t-test.Results: No SCs could be obtained from periodontitis-affected teeth without phase I periodontal treatment. The viability of cells was 0.86±0.13 OD/540 in healthy group and 0.4±0.25 OD/540 in periodontitis-affected group (P=0.035. The proliferation ability (population doubling time of cells obtained from healthy teeth was 4.22±1.23 hours. This value was 2.3±0.35 hours for those obtained from periodontitis-affected teeth (P=0.02.Conclusions: Viability and proliferation ability of cells isolated from the periodontium of healthy teeth were significantly greater than those of cells isolated from the periodontitis-affected teeth.Keywords: Stem Cells; Periodontitis; Tooth; Regeneration

  11. PREFACE: Water in confined geometries

    Science.gov (United States)

    Rovere, Mauro

    2004-11-01

    The study of water confined in complex systems in solid or gel phases and/or in contact with macromolecules is relevant to many important processes ranging from industrial applications such as catalysis and soil chemistry, to biological processes such as protein folding or ionic transport in membranes. Thermodynamics, phase behaviour and the molecular mobility of water have been observed to change upon confinement depending on the properties of the substrate. In particular, polar substrates perturb the hydrogen bond network of water, inducing large changes in the properties upon freezing. Understanding how the connected random hydrogen bond network of bulk water is modified when water is confined in small cavities inside a substrate material is very important for studies of stability and the enzymatic activity of proteins, oil recovery or heterogeneous catalysis, where water-substrate interactions play a fundamental role. The modifications of the short-range order in the liquid depend on the nature of the water-substrate interaction, hydrophilic or hydrophobic, as well as on its spatial range and on the geometry of the substrate. Despite extensive study, both experimentally and by computer simulation, there remain a number of open problems. In the many experimental studies of confined water, those performed on water in Vycor are of particular interest for computer simulation and theoretical studies since Vycor is a porous silica glass characterized by a quite sharp distribution of pore sizes and a strong capability to absorb water. It can be considered as a good candidate for studying the general behaviour of water in hydrophilic nanopores. But there there have been a number of studies of water confined in more complex substrates, where the interpretation of experiments and computer simulation is more difficult, such as in zeolites or in aerogels or in contact with membranes. Of the many problems to consider we can mention the study of supercooled water. It is

  12. Development of cyclic shedding teeth from semi-shedding teeth: the inner dental arcade of the stem osteichthyan Lophosteus

    Science.gov (United States)

    Chen, Donglei; Blom, Henning; Sanchez, Sophie; Tafforeau, Paul; Märss, Tiiu; Ahlberg, Per E.

    2017-05-01

    The numerous cushion-shaped tooth-bearing plates attributed to the stem group osteichthyan Lophosteus superbus, which are argued here to represent an early form of the osteichthyan inner dental arcade, display a previously unknown and presumably primitive mode of tooth shedding by basal hard tissue resorption. They carry regularly spaced, recumbent, gently recurved teeth arranged in transverse tooth files that diverge towards the lingual margin of the cushion. Three-dimensional reconstruction from propagation phase-contrast synchrotron microtomography (PPC-SRµCT) reveals remnants of the first-generation teeth embedded in the basal plate, a feature never previously observed in any taxon. These teeth were shed by semi-basal resorption with the periphery of their bases retained as dentine rings. The rings are highly overlapped, which evidences tooth shedding prior to adding the next first-generation tooth at the growing edge of the plate. The first generation of teeth is thus diachronous. Successor teeth at the same sites underwent cyclical replacing and shedding through basal resorption, producing stacks of buried resorption surfaces separated by bone of attachment. The number and spatial arrangement of resorption surfaces elucidates that basal resorption of replacement teeth had taken place at the older tooth sites before the addition of the youngest first-generation teeth at the lingual margin. Thus, the replacement tooth buds cannot have been generated by a single permanent dental lamina at the lingual edge of the tooth cushion, but must have arisen either from successional dental laminae associated with the individual predecessor teeth, or directly from the dental epithelium of these teeth. The virtual histological dissection of these Late Silurian microfossils broadens our understanding of the development of the gnathostome dental systems and the acquisition of the osteichthyan-type of tooth replacement.

  13. Quantum groups: Geometry and applications

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Chong -Sun [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Theoretical Physics Group; Univ. of California, Berkeley, CA (United States)

    1996-05-13

    The main theme of this thesis is a study of the geometry of quantum groups and quantum spaces, with the hope that they will be useful for the construction of quantum field theory with quantum group symmetry. The main tool used is the Faddeev-Reshetikhin-Takhtajan description of quantum groups. A few content-rich examples of quantum complex spaces with quantum group symmetry are treated in details. In chapter 1, the author reviews some of the basic concepts and notions for Hopf algebras and other background materials. In chapter 2, he studies the vector fields of quantum groups. A compact realization of these vector fields as pseudodifferential operators acting on the linear quantum spaces is given. In chapter 3, he describes the quantum sphere as a complex quantum manifold by means of a quantum stereographic projection. A covariant calculus is introduced. An interesting property of this calculus is the existence of a one-form realization of the exterior differential operator. The concept of a braided comodule is introduced and a braided algebra of quantum spheres is constructed. In chapter 4, the author considers the more general higher dimensional quantum complex projective spaces and the quantum Grassman manifolds. Differential calculus, integration and braiding can be introduced as in the one dimensional case. Finally, in chapter 5, he studies the framework of quantum principal bundle and construct the q-deformed Dirac monopole as a quantum principal bundle with a quantum sphere as the base and a U(1) with non-commutative calculus as the fiber. The first Chern class can be introduced and integrated to give the monopole charge.

  14. Algebra and Geometry of Hamilton's Quaternions

    Indian Academy of Sciences (India)

    IAS Admin

    Inspired by the relation between the algebra of complex numbers and plane geometry, William. Rowan Hamilton sought an algebra of triples for application to three-dimensional geometry. Un- able to multiply and divide triples, he invented a non-commutative division algebra of quadru- ples, in what he considered his most ...

  15. Cognitive Styles, Dynamic Geometry and Measurement Performance

    Science.gov (United States)

    Pitta-Pantazi, Demetra; Christou, Constantinos

    2009-01-01

    This paper reports the outcomes of an empirical study undertaken to investigate the effect of students' cognitive styles on achievement in measurement tasks in a dynamic geometry learning environment, and to explore the ability of dynamic geometry learning in accommodating different cognitive styles and enhancing students' learning. A total of 49…

  16. Reasoning by Contradiction in Dynamic Geometry

    Science.gov (United States)

    Baccaglini-Frank, Anna; Antonini, Samuele; Leung, Allen; Mariotti, Maria Alessandra

    2013-01-01

    This paper addresses contributions that dynamic geometry systems (DGSs) may give in reasoning by contradiction in geometry. We present analyses of three excerpts of students' work and use the notion of pseudo object, elaborated from previous research, to show some specificities of DGS in constructing proof by contradiction. In particular, we…

  17. Visual and Analytic Strategies in Geometry

    Science.gov (United States)

    Kospentaris, George; Vosniadou, Stella; Kazic, Smaragda; Thanou, Emilian

    2016-01-01

    We argue that there is an increasing reliance on analytic strategies compared to visuospatial strategies, which is related to geometry expertise and not on individual differences in cognitive style. A Visual/Analytic Strategy Test (VAST) was developed to investigate the use of visuo-spatial and analytic strategies in geometry in 30 mathematics…

  18. Symposium on Differential Geometry and Differential Equations

    CERN Document Server

    Berger, Marcel; Bryant, Robert

    1987-01-01

    The DD6 Symposium was, like its predecessors DD1 to DD5 both a research symposium and a summer seminar and concentrated on differential geometry. This volume contains a selection of the invited papers and some additional contributions. They cover recent advances and principal trends in current research in differential geometry.

  19. A Multivariate Model of Achievement in Geometry

    Science.gov (United States)

    Bailey, MarLynn; Taasoobshirazi, Gita; Carr, Martha

    2014-01-01

    Previous studies have shown that several key variables influence student achievement in geometry, but no research has been conducted to determine how these variables interact. A model of achievement in geometry was tested on a sample of 102 high school students. Structural equation modeling was used to test hypothesized relationships among…

  20. Making Euclidean Geometry Compulsory: Are We Prepared?

    Science.gov (United States)

    Van Putten, Sonja; Howie, Sarah; Stols, Gerrit

    2010-01-01

    This study investigated the attitude towards, as well as the level of understanding of Euclidean geometry in pre-service mathematics education (PME) students. In order to do so, a case study was undertaken within which a one group pre-post-test procedure was conducted around a geometry module, and a representative group of students was interviewed…

  1. Applications Of Nonclassical Geometry To String Theory

    CERN Document Server

    Zunger, Y

    2003-01-01

    String theory is built on a foundation of geometry. This thesis examines several applications of geometry beyond the classical Riemannian geometry of curved surfaces. The first part considers the use of extended spaces with internal dimensions to each point (“twistors”) to probe systems with a great deal of symmetry but complicated dynamics. These systems are of critical interest in understanding holographic phenomena in string theory and the origins of entropy. We develop a twistor formulation of coset spaces and use this to write simplified actions for particles and strings on anti-de Sitter space, which are easier to quantize than the ordinary (highly nonlinear) actions. In the second part, we consider two aspects of noncommutative geometry, a generalization of ordinary geometry where points are “fuzzed out” and functions of space become noncommuting operators. We first examine strings with one endpoint on a D-brane in a background magnetic field. (Strings with both ...

  2. Special metrics and group actions in geometry

    CERN Document Server

    Fino, Anna; Musso, Emilio; Podestà, Fabio; Vezzoni, Luigi

    2017-01-01

    The volume is a follow-up to the INdAM meeting “Special metrics and quaternionic geometry” held in Rome in November 2015. It offers a panoramic view of a selection of cutting-edge topics in differential geometry, including 4-manifolds, quaternionic and octonionic geometry, twistor spaces, harmonic maps, spinors, complex and conformal geometry, homogeneous spaces and nilmanifolds, special geometries in dimensions 5–8, gauge theory, symplectic and toric manifolds, exceptional holonomy and integrable systems. The workshop was held in honor of Simon Salamon, a leading international scholar at the forefront of academic research who has made significant contributions to all these subjects. The articles published here represent a compelling testimony to Salamon’s profound and longstanding impact on the mathematical community. Target readership includes graduate students and researchers working in Riemannian and complex geometry, Lie theory and mathematical physics.

  3. FINAL REPORT: GEOMETRY AND ELEMENTARY PARTICLE PHYSICS

    Energy Technology Data Exchange (ETDEWEB)

    Singer, Isadore M.

    2008-03-04

    The effect on mathematics of collaborations between high-energy theoretical physics and modern mathematics has been remarkable. Mirror symmetry has revolutionized enumerative geometry, and Seiberg-Witten invariants have greatly simplified the study of four manifolds. And because of their application to string theory, physicists now need to know cohomology theory, characteristic classes, index theory, K-theory, algebraic geometry, differential geometry, and non-commutative geometry. Much more is coming. We are experiencing a deeper contact between the two sciences, which will stimulate new mathematics essential to the physicists’ quest for the unification of quantum mechanics and relativity. Our grant, supported by the Department of Energy for twelve years, has been instrumental in promoting an effective interaction between geometry and string theory, by supporting the Mathematical Physics seminar, postdoc research, collaborations, graduate students and several research papers.

  4. Geometry-Related Children's Literature Improves the Geometry Achievement and Attitudes of Second-Grade Students

    Science.gov (United States)

    McAndrew, Erica M.; Morris, Wendy L.; Fennell, Francis

    2017-01-01

    Use of mathematics-related literature can engage students' interest and increase their understanding of mathematical concepts. A quasi-experimental study of two second-grade classrooms assessed whether daily inclusion of geometry-related literature in the classroom improved attitudes toward geometry and achievement in geometry. Consistent with the…

  5. Visuospatial Working Memory in Intuitive Geometry, and in Academic Achievement in Geometry

    Science.gov (United States)

    Giofre, David; Mammarella, Irene C.; Ronconi, Lucia; Cornoldi, Cesare

    2013-01-01

    A study was conducted on the involvement of visuospatial working memory (VSWM) in intuitive geometry and in school performance in geometry at secondary school. A total of 166 pupils were administered: (1) six VSWM tasks, comprising simple storage and complex span tasks; and (2) the intuitive geometry task devised by Dehaene, Izard, Pica, and…

  6. Analogy and Dynamic Geometry System Used to Introduce Three-Dimensional Geometry

    Science.gov (United States)

    Mammana, M. F.; Micale, B.; Pennisi, M.

    2012-01-01

    We present a sequence of classroom activities on Euclidean geometry, both plane and space geometry, used to make three dimensional geometry more catchy and simple. The activity consists of a guided research activity that leads the students to discover unexpected properties of two apparently distant geometrical entities, quadrilaterals and…

  7. A review on vital pulp therapy in primary teeth.

    Science.gov (United States)

    Parisay, Iman; Ghoddusi, Jamileh; Forghani, Maryam

    2015-01-01

    Maintaining deciduous teeth in function until their natural exfoliation is absolutely necessary. Vital pulp therapy (VPT) is a way of saving deciduous teeth. The most important factors in success of VPT are the early diagnosis of pulp and periradicular status, preservation of the pulp vitality and proper vascularization of the pulp. Development of new biomaterials with suitable biocompatibility and seal has changed the attitudes towards preserving the reversible pulp in cariously exposed teeth. Before exposure and irreversible involvement of the pulp, indirect pulp capping (IPC) is the treatment of choice, but after the spread of inflammation within the pulp chamber and establishment of irreversible pulpitis, removal of inflamed pulp tissue is recommended. In this review, new concepts in preservation of the healthy pulp tissue in deciduous teeth and induction of the reparative dentin formation with new biomaterials instead of devitalization and the consequent destruction of vital tissues are discussed.

  8. The longevity of different restorations in primary teeth

    DEFF Research Database (Denmark)

    Qvist, Vibeke; Poulsen, Agneta; Teglers, Poul Thorpen

    2010-01-01

    This paper reviews three published papers and adds results from a fourth study which aimed to determine which restorative material would be the best alternative(s) to amalgam (AM) in primary teeth....

  9. Implant restoration of external resorption teeth in the esthetic zone.

    Science.gov (United States)

    Block, Michael S; Casadaban, Michael C

    2005-11-01

    The purposes of this article were to review the literature for treatment of teeth with external resorption secondary to avulsive injuries and to illustrate treatment of patients with teeth following different clinical scenarios to develop a predictable course of therapy. Cases that demonstrate treatment of teeth with external resorption following injury during the growing period, external resorption treated with a delayed approach after tooth extraction, immediate grafting of the extraction site to repair labial bone loss, and immediate implant placement with provisionalization are shown. Based on a review of the literature, the decision to place dental implants to replace teeth with external resorption can be timed depending on the location and type of the resorption, with excellent esthetic results.

  10. [Decision-making of restorations for endodontically treated teeth].

    Science.gov (United States)

    Zhi, Chen; Binwen, Chen

    2015-04-01

    Coronal restoration of endodontically treated teeth may be viewed as one of the main parameters that influence the outcome of endodontic treatment. The purposes of restoring endodontically-treated teeth include preventing recontamination of the root canal system and periapical area, replacing the compromised dental hard tissue, restoring the coronal morphology and function, providing necessary strength for the restoration/tooth complex for functional stress, and avoiding crown and/or root fracture. This article reviewed recent researches on the restoration of endodontically treated teeth, provided evidence for clinical practice on topics as when to restore them, basic principles to be considered during treatment planning, and specific restoration options for both anterior and posterior teeth under different functional occulsal load conditions. Several issues should be taken into account during the decision making process, such as remaining tooth tissue, functional masticatory forces, comprehensive oral rehabilitation, and esthetic requirements.

  11. Preservation of Seawater Strontium and Neodymium in Fossil Fish Teeth

    Science.gov (United States)

    Martin, E. E.; Scher, H.

    2003-04-01

    Sr isotope chemostratigraphy of fossil fish teeth, or ichthyoliths, has been suggested as a potential technique for dating carbonate-poor sediments, such as red clays. Data from three DSDP/ODP sites: site 757 in the Indian Ocean, and sites 689 and 1090 in the Southern Ocean, illustrate that fish teeth do not reliably record seawater Sr isotopic signatures. We compared 87Sr/86Sr values measured on foraminifera, fish teeth and pore waters for all three sites for intervals ranging from 0.5 Ma to 38 Ma. Pore waters for both sites 757 and 1090 are less radiogenic than contemporaneous seawater by 0.00010 to 0.00040. Both sites contain a hiatus midway through the section, and the fish teeth and foraminifera values agree below the hiatuses. However, in the overlying section fish teeth values are 0.00008 to 0.00017 lower than contemporaneous foraminifera, indicating that they are altered in the direction of pore water Sr. Age estimates based on Sr isotope chemostratigraphy of these teeth would yield ages that are ˜1.5 m.y. (site 1090) to 4 m.y. (site 757) too old. In contrast, pore water values are more radiogenic than contemporaneous seawater for the section from 25 to 36 Ma at site 689 (Egeberg, et al., 1990). As a result, the fish teeth values plot above the foraminifera values by ˜0.00013, an offset that correlates to an age error of ˜3.5 m.y. for this section of the curve. The hydroxyfluorapatite of fossil fish teeth is a post mortem diagenetic product. Therefore, the integrity of the Sr isotopic signal depends on the timing and rate of recrystallization, as well as the composition of pore waters. Our data imply that the teeth continue to exchange Sr during burial. Consequently, age estimates based on Sr isotopes of fish teeth in sections with altered pore waters can provide gross age determinations (+/- 5 m.y.), but can not be used to fine tune age models. Fish teeth are also utilized as archives for deep water Nd isotopes. The hydroxyapatite of living fish teeth

  12. Cultural significance of primary teeth for caregivers in Northeast Brazil.

    Science.gov (United States)

    Nations, Marilyn K; Calvasina, Paola Gondim; Martin, Michele N; Dias, Hilma Fontenele

    2008-04-01

    This anthropological study critically evaluates Brazilian caregivers' symbolic production and significance of their malnourished offspring's primary teeth, as well as their own, and describes popular dental practices. From January to June 2004, ethnographic interviews of 27 poor, low-literacy mothers were conducted at a public Malnutrition Treatment Center in Fortaleza, Ceará State. Participant observation of clinical pathways and home environments supplemented the data. Content analysis was performed. Results confirm that primary teeth are imbued with cultural significance in Northeast Brazil. Mothers examine mouths, perceive signs of decay, associate primary with permanent tooth healthiness, identify ethnodental illnesses, seek assistance, and perform rituals with exfoliated teeth. The mother's motivation to care for primary teeth is sparked by her memories of past toothache and attempts to avoid stigma and discrimination. Social determinants, not mothers' beliefs or behaviors, are the most critical obstacles to effective dental care. Legitimizing lay knowledge and empowering caregivers and children can improve oral health in Northeast Brazil.

  13. Mouth and Teeth: How To Keep Them Healthy

    Science.gov (United States)

    ... as you get older. Taking care of your teeth means brushing and flossing every day and seeing the dentist regularly.Path to improved healthA healthy mouth is more important than you might think. Consider everything you expect ...

  14. Advanced endodontic developments in pulpectomy of primary teeth.

    Science.gov (United States)

    Yanko, Nataliia; Khmil, Olena; Kaskova, Lyudmyla; Vashchenko, Irina

    2016-01-01

    To appraise studies about pulpectomy in primary teeth with nickel-titanium rotary files and smear layer removal and to find out may these developments enhance pulpectomy outcomes in primary teeth. A systematic search was implemented for PubMed, Google and Google Scholar between the years 1995-January 2016 to identify eligible studies. Studies design was established according to the CEBM recommendations. Evidence quality of studies was appraised by risk of bias. Six studies about pulpectomy met the inclusion criteria, of which five were randomized controlled trials. Only one research demonstrates the enhanced outcome of pulpectomy in primary teeth with smear layer removal. Chosen studies have low overall evidence quality. Given the paucity, high heterogeneity of high-quality articles and their level of bias, recommendation for the use of nickel-titanium rotary files and smear layer removal in pulpectomy in primary teeth can yet not be formulated.

  15. Histopathologic and SEM analysis of primary teeth with pulpectomy failure.

    Science.gov (United States)

    Tannure, Patricia Nivoloni; Barcelos, Roberta; Portela, Maristela Barbosa; Gleiser, Rogerio; Primo, Laura Guimarães

    2009-07-01

    The objective of this study was to identify the probable factors associated with pulpectomy failure of primary teeth through qualitative analysis by histopathology (HIST) and scanning electron microscopy (SEM). A longitudinal clinical investigation of the efficacy of pulpectomy in primary teeth with irreversible pulp changes was carried out with 133 teeth (66 children) evaluated up to 48 months. The overall success was 86.1% during follow-up. Of the 18 teeth extracted as a result of treatment failure, 8 presented sufficiently undamaged roots to be randomly selected for HIST (n = 4) and SEM (n = 4) analysis. Necrotic tissue and chronic inflammatory cells were observed in all specimens submitted to HIST as external radicular resorption associated with Howship's lacunae. SEM analysis showed apical and furcation areas heavily infected with microorganisms and Howship's lacunae. These findings suggest that the main factors responsible for pulpectomy failure were technique limitations associated with the morphological irregularities created by external/inflammatory resorption.

  16. Triplication of Deciduous Teeth: A Rare Dental Anomaly

    African Journals Online (AJOL)

    Figure 6]. Based on these findings, a final diagnosis of incomplete fusion was confirmed. Figure 1: Pre‑operative intraoral photograph. Figure 2: Pre‑operative intraoral maxillary occlusal view depicting triple fusion. Figure 3: Extracted fused teeth.

  17. Astronauts Culbertson and Bursch brush their teeth on Discovery's middeck

    Science.gov (United States)

    1993-01-01

    Astronauts Frank L. Culbertson (right), mission commander, and Daniel W. Bursch, mission specialist, brush their teeth on Discovery's middeck. Two sleep restraints form part of the backdrop for the photograph.

  18. The management of over closured anterior teeth due to attrition

    Directory of Open Access Journals (Sweden)

    Eha Djulaeha

    2009-12-01

    Full Text Available Background: Tooth is the hardest tissue in human body, that can be injured because of attrition process. For old people, denture attrition process is caused by psysiological process relating with the mastication function which also supported by some bad habits such an bruxism, premature contact, and consuming habit of abrasive food. Attrition or abrasion can also be happened with patien’t dentition who does not have teeth subtutition for long time due the lost of their maxillary as well as mandibulary. The pasient will loose their vertical dimension of occlusion, injure, and the lower jaw becomes over closed which is called over closure. Purpose: This article reported the management of over closured anterior teeth due to attrition. Case: a seventy six year old woman patient came to Prosthodontic Clinic in Faculty of Dentistry, Airlangga University, to rehabilitate her upper and lower severe attrited anterior teeth and her posterior teeth. The patient has experienced of wearing acrylic removable mandibular partial denture ten years ago. Unfortunaly, the denture was uncomfortable, and she did not wear it anymore since five years ago. Case management: The severe attrition of anterior teeth with the lost of occlusal vertical dimension can be treated by improving the occlusal vertical dimension gradually. The treatment is then followed by the increasing of the height of the anterior teeth by lengthening the crown teeth of upper jaw with 12 units of span bridge and the acrylic removable partial denture of lower jaw. Conclusion: The severe attrition of anterior teeth with the lost of occlusal vertical dimension can be treated by improving the occlusal vertical dimension gradually, using long span bridge and acrylic removable partial denture.

  19. Bilateral Supernumerary Teeth in Deciduous Dentition-A Rarity

    OpenAIRE

    Acharya, Sonu; Ghosh, Chiranjit; Mondal, Pradeep Kumar

    2014-01-01

    Supernumerary teeth are considered as one of the most significant dental anomalies during the primary and early mixed dentition stages. They are of great concern to the dentists and parents because of the eruption, occlusal, and esthetic problems they can cause. Supernumerary teeth occur more frequently in the permanent dentition but rarely in primary dentition and more often seen in males. A supernumerary tooth in the primary dentition can cause ectopic or delayed eruption of permanent centr...

  20. Mounting ground sections of teeth: Cyanoacrylate adhesive versus Canada balsam

    OpenAIRE

    Manogna R.L. Vangala; Amrutha Rudraraju; Subramanyam, R. V.

    2016-01-01

    Introduction: Hard tissues can be studied by either decalcification or by preparing ground sections. Various mounting media have been tried and used for ground sections of teeth. However, there are very few studies on the use of cyanoacrylate adhesive as a mounting medium. Aims: The aim of our study was to evaluate the efficacy of cyanoacrylate adhesive (Fevikwik™) as a mounting medium for ground sections of teeth and to compare these ground sections with those mounted with Canada balsam. Mat...

  1. Clinical Considerations in Orthodontic Treatment of Teeth with Dentoalveolar Trauma

    OpenAIRE

    Torres Restrepo, Adriana María; Preciado Sánchez, José Camilo

    2014-01-01

    Dentoalveolar trauma is a very common public health problem. Its influence goes beyond accidents and their impact on teeth, because in the future it becomes a decisive factor if orthodontic treatment is required, because these traumas tend to lead to complications such as root resorption and pulp necrosis. Proper treatment of teeth with a medical history of trauma is essential for successful orthodontic treatment. Los traumas dentoalveolares son un problema de salud pública muy común. La i...

  2. Rotary endodontics in primary teeth – A review

    OpenAIRE

    George, Sageena; Anandaraj, S.; Issac, Jyoti S.; John, Sheen A.; Harris, Anoop

    2015-01-01

    Endodontic treatment in primary teeth can be challenging and time consuming, especially during canal preparation, which is considered one of the most important steps in root canal therapy. The conventional instrumentation technique for primary teeth remains the “gold-standard” over hand instrumentation, which makes procedures much more time consuming and adversely affects both clinicians and patients. Recently nickel–titanium (Ni–Ti) rotary files have been developed for use in pediatric endod...

  3. Antibacterial Effect of Diode Laser in Pulpectomy of Primary Teeth

    OpenAIRE

    Bahrololoomi, Zahra; Fekrazad, Reza; Shiva ZAMANINEJAD

    2017-01-01

    Introduction: Laser irradiation has been suggested as an adjunct to traditional methods of canal preparation but few studies are available on the antibacterial effect of diode laser in pulpectomy of primary teeth. The purpose of the present study is to investigate the antibacterial effect of diode laser in pulpectomy of primary teeth, in addition to define the optimal and harmless diode lasing conditions in the root canal.

  4. Treatment planning decisions: implant placement versus preserving natural teeth.

    Science.gov (United States)

    Moshaverinia, Alireza; Kar, Klan; Chee, Winston W L

    2014-12-01

    Dental implants are routinely used as a treatment modality for replacing missing teeth. An assessment of whether to extract teeth and place implants or preserve natural dentition can be a complex decision-making process. The purpose of this article is to review some of the factors that influence prosthetic planning of functional and esthetic rehabilitation for patients with diseased dentition either with conventional treatment options or with extractions and replacement with implant-supported prosthesis.

  5. Pulp Revascularization For Immature Replanted Teeth: A Case Report.

    OpenAIRE

    Nagata, J Y; Rocha-Lima, T F; Gomes, B P; Ferraz, C C; Zaia, A A; Souza-Filho, F J; De Jesus-Soares, A

    2016-01-01

    Immature avulsed teeth are not usually treated with pulp revascularization because of the possibility of complications. However, this therapy has shown success in the treatment of immature teeth with periapical lesions. This report describes the case of an immature replanted tooth that was successfully treated by pulp revascularization. An 8-year-old boy suffered avulsion on his maxillary left lateral incisor. The tooth showed incomplete root development and was replanted after 30 minutes. Af...

  6. Antioxidant therapy enhances pulpal healing in bleached teeth.

    Science.gov (United States)

    Lima, Adriano Fonseca; Marques, Marcelo Rocha; Soares, Diana Gabriela; Hebling, Josimeri; Marchi, Giselle Maria; de Souza Costa, Carlos Alberto

    2016-02-01

    The purpose of this study was to evaluate the histopathological effects of an antioxidant therapy on the pulp tissue of rat teeth exposed to a bleaching gel with 35% hydrogen peroxide. Forty rats were subjected to oral ingestion by gavage of distilled water (DW) or ascorbic acid (AA) 90 min before the bleaching therapy. For the bleaching treatment, the agent was applied twice for 5 min each to buccal surfaces of the first right mandibular molars. Then, the animals were sacrificed at 6 hr, 24 hr, 3 day, or 7 day post-bleaching, and the teeth were processed for microscopic evaluation of the pulp tissue. At 6 hr, the pulp tissue showed moderate inflammatory reactions in all teeth of both groups. In the DW and AA groups, 100% and 80% of teeth exhibited pulp tissue with significant necrosis and intense tissue disorganization, respectively. At 24 hr, the AA-treated group demonstrated a greater regenerative capability than the DW group, with less intense inflammatory reaction and new odontoblast layer formation in 60% of the teeth. For up to the 7 day period, the areas of pulpal necrosis were replaced by viable connective tissue, and the dentin was underlined by differentiated odontoblast-like cells in most teeth of both groups. A slight reduction in initial pulpal damage during post-bleaching was promoted by AA therapy. However, the pulp tissue of AA-treated animals featured faster regenerative potential over time.

  7. Comparative analysis of human and bovine teeth: radiographic density

    Directory of Open Access Journals (Sweden)

    Jefferson Luis Oshiro Tanaka

    2008-12-01

    Full Text Available Since bovine teeth have been used as substitutes for human teeth in in vitro dental studies, the aim of this study was to compare the radiographic density of bovine teeth with that of human teeth to evaluate their usability for radiographic studies. Thirty bovine and twenty human teeth were cut transversally in 1 millimeter-thick slices. The slices were X-rayed using a digital radiographic system and an intraoral X-ray machine at 65 kVp and 7 mA. The exposure time (0.08 s and the target-sensor distance (40 cm were standardized for all the radiographs. The radiographic densities of the enamel, coronal dentin and radicular dentin of each slice were obtained separately using the "histogram" tool of Adobe Photoshop 7.0 software. The mean radiographic densities of the enamel, coronal dentin and radicular dentin were calculated by the arithmetic mean of the slices of each tooth. One-way ANOVA demonstrated statistically significant differences for the densities of bovine and human enamel (p 0.05. Based on the results, the authors concluded that: a the radiographic density of bovine enamel is significantly higher than that of human enamel; b the radiodensity of bovine coronal dentin is statistically lower than the radiodensity of human coronal dentin; bovine radicular dentin is also less radiodense than human radicular dentin, although this difference was not statistically significant; c bovine teeth should be used with care in radiographic in vitro studies.

  8. Antioxidant therapy enhances pulpal healing in bleached teeth

    Directory of Open Access Journals (Sweden)

    Adriano Fonseca Lima

    2016-02-01

    Full Text Available Objectives The purpose of this study was to evaluate the histopathological effects of an antioxidant therapy on the pulp tissue of rat teeth exposed to a bleaching gel with 35% hydrogen peroxide. Materials and Methods Forty rats were subjected to oral ingestion by gavage of distilled water (DW or ascorbic acid (AA 90 min before the bleaching therapy. For the bleaching treatment, the agent was applied twice for 5 min each to buccal surfaces of the first right mandibular molars. Then, the animals were sacrificed at 6 hr, 24 hr, 3 day, or 7 day post-bleaching, and the teeth were processed for microscopic evaluation of the pulp tissue. Results At 6 hr, the pulp tissue showed moderate inflammatory reactions in all teeth of both groups. In the DW and AA groups, 100% and 80% of teeth exhibited pulp tissue with significant necrosis and intense tissue disorganization, respectively. At 24 hr, the AA-treated group demonstrated a greater regenerative capability than the DW group, with less intense inflammatory reaction and new odontoblast layer formation in 60% of the teeth. For up to the 7 day period, the areas of pulpal necrosis were replaced by viable connective tissue, and the dentin was underlined by differentiated odontoblast-like cells in most teeth of both groups. Conclusions A slight reduction in initial pulpal damage during post-bleaching was promoted by AA therapy. However, the pulp tissue of AA-treated animals featured faster regenerative potential over time

  9. Primes, Geometry and Condensed Matter

    Directory of Open Access Journals (Sweden)

    Al Rabeh R. H.

    2009-07-01

    Full Text Available Fascination with primes dates back to the Greeks and before. Primes are named by some "the elementary particles of arithmetic" as every nonprime integer is made of a unique set of primes. In this article we point to new connections between primes, geometry and physics which show that primes could be called "the elementary particles of physics" too. This study considers the problem of closely packing similar circles/spheres in 2D/3D space. This is in effect a discretization process of space and the allowable number in a pack is found to lead to some unexpected cases of prime configurations which is independent of the size of the constituents. We next suggest that a non-prime can be considered geometrically as a symmetric collection that is separable (factorable into similar parts- six is two threes or three twos for example. A collection that has no such symmetry is a prime. As a result, a physical prime aggregate is more difficult to split symmetrically resulting in an inherent stability. This "number/physical" stability idea applies to bigger collections made from smaller (prime units leading to larger stable prime structures in a limitless scaling up process. The distribution of primes among numbers can be understood better using the packing ideas described here and we further suggest that differing numbers (and values of distinct prime factors making a nonprime collection is an important factor in determining the probability and method of possible and subsequent disintegration. Disintegration is bound by energy conservation and is closely related to symmetry by Noether theorems. Thinking of condensed matter as the packing of identical elements, we examine plots of the masses of chemical elements of the periodic table, and also those of the elementary particles of physics, and show that prime packing rules seem to play a role in the make up of matter. The plots show convincingly that the growth of prime numbers and that of the masses of

  10. Primes, Geometry and Condensed Matter

    Directory of Open Access Journals (Sweden)

    Al Rabeh R. H.

    2009-07-01

    Full Text Available Fascination with primes dates back to the Greeks and before. Primes are named by some “the elementary particles of arithmetic” as every nonprime integer is made of a unique set of primes. In this article we point to new connections between primes, geometry and physics which show that primes could be called “the elementary particles of physics” too. This study considers the problem of closely packing similar circles / spheres in 2D / 3D space. This is in effect a discretization process of space and the allowable num- ber in a pack is found to lead to some unexpected cases of prime configurations which is independent of the size of the constituents. We next suggest that a non-prime can be considered geometrically as a symmetric collection that is separable (factorable into similar parts- six is two threes or three twos for example. A collection that has no such symmetry is a prime. As a result, a physical prime aggregate is more difficult to split symmetrically resulting in an inherent stability. This “number / physical” stability idea applies to bigger collections made from smaller (prime units leading to larger sta- ble prime structures in a limitless scaling up process. The distribution of primes among numbers can be understood better using the packing ideas described here and we further suggest that differing numbers (and values of distinct prime factors making a nonprime collection is an important factor in determining the probability and method of possible and subsequent disintegration. Disintegration is bound by energy conservation and is closely related to symmetry by Noether theorems. Thinking of condensed matter as the packing of identical elements, we examine plots of the masses of chemical elements of the periodic table, and also those of the elementary particles of physics, and show that prime packing rules seem to play a role in the make up of matter. The plots show con- vincingly that the growth of prime numbers and that

  11. basement reservoir geometry and properties

    Science.gov (United States)

    Walter, bastien; Geraud, yves; Diraison, marc

    2017-04-01

    Basement reservoirs are nowadays frequently investigated for deep-seated fluid resources (e.g. geothermal energy, groundwater, hydrocarbons). The term 'basement' generally refers to crystalline and metamorphic formations, where matrix porosity is negligible in fresh basement rocks. Geothermal production of such unconventional reservoirs is controlled by brittle structures and altered rock matrix, resulting of a combination of different tectonic, hydrothermal or weathering phenomena. This work aims to characterize the petro-structural and petrophysical properties of two basement surface analogue case studies in geological extensive setting (the Albert Lake rift in Uganda; the Ifni proximal margin of the South West Morocco Atlantic coast). Different datasets, using field structural study, geophysical acquisition and laboratory petrophysical measurements, were integrated to describe the multi-scale geometry of the porous network of such fractured and weathered basement formations. This study points out the multi-scale distribution of all the features constituting the reservoir, over ten orders of magnitude from the pluri-kilometric scale of the major tectonics structures to the infra-millimetric scale of the secondary micro-porosity of fractured and weathered basements units. Major fault zones, with relatively thick and impermeable fault core structures, control the 'compartmentalization' of the reservoir by dividing it into several structural blocks. The analysis of these fault zones highlights the necessity for the basement reservoirs to be characterized by a highly connected fault and fracture system, where structure intersections represent the main fluid drainage areas between and within the reservoir's structural blocks. The suitable fluid storage areas in these reservoirs correspond to the damage zone of all the fault structures developed during the tectonic evolution of the basement and the weathered units of the basement roof developed during pre

  12. Moving KML geometry elements within Google Earth

    Science.gov (United States)

    Zhu, Liang-feng; Wang, Xi-feng; Pan, Xin

    2014-11-01

    During the process of modeling and visualizing geospatial information on the Google Earth virtual globe, there is an increasing demand to carry out such operations as moving geospatial objects defined by KML geometry elements horizontally or vertically. Due to the absence of the functionality and user interface for performing the moving transformation, it is either hard or impossible to interactively move multiple geospatial objects only using the existing Google Earth desktop application, especially when the data sets are in large volume. In this paper, we present a general framework and associated implementation methods for moving multiple KML geometry elements within Google Earth. In our proposed framework, we first load KML objects into the Google Earth plug-in, and then extract KML geometry elements from the imported KML objects. Subsequently, we interactively control the movement distance along a specified orientation by employing a custom user interface, calculate the transformed geographic location for each KML geometry element, and adjust geographic coordinates of the points in each KML objects. And finally, transformed KML geometry elements can be displayed in Google Earth for 3D visualization and spatial analysis. A key advantage of the proposed framework is that it provides a simple, uniform and efficient user interface for moving multiple KML geometry elements within Google Earth. More importantly, the proposed framework and associated implementations can be conveniently integrated into other customizable Google Earth applications to support interactively visualizing and analyzing geospatial objects defined by KML geometry elements.

  13. Discrete quantum geometries and their effective dimension

    Energy Technology Data Exchange (ETDEWEB)

    Thuerigen, Johannes

    2015-07-02

    In several approaches towards a quantum theory of gravity, such as group field theory and loop quantum gravity, quantum states and histories of the geometric degrees of freedom turn out to be based on discrete spacetime. The most pressing issue is then how the smooth geometries of general relativity, expressed in terms of suitable geometric observables, arise from such discrete quantum geometries in some semiclassical and continuum limit. In this thesis I tackle the question of suitable observables focusing on the effective dimension of discrete quantum geometries. For this purpose I give a purely combinatorial description of the discrete structures which these geometries have support on. As a side topic, this allows to present an extension of group field theory to cover the combinatorially larger kinematical state space of loop quantum gravity. Moreover, I introduce a discrete calculus for fields on such fundamentally discrete geometries with a particular focus on the Laplacian. This permits to define the effective-dimension observables for quantum geometries. Analysing various classes of quantum geometries, I find as a general result that the spectral dimension is more sensitive to the underlying combinatorial structure than to the details of the additional geometric data thereon. Semiclassical states in loop quantum gravity approximate the classical geometries they are peaking on rather well and there are no indications for stronger quantum effects. On the other hand, in the context of a more general model of states which are superposition over a large number of complexes, based on analytic solutions, there is a flow of the spectral dimension from the topological dimension d on low energy scales to a real number between 0 and d on high energy scales. In the particular case of 1 these results allow to understand the quantum geometry as effectively fractal.

  14. [Comparison between children with missing anterior deciduous teeth and posterior deciduous teeth by analysis of speech sounds].

    Science.gov (United States)

    Takagi, M; Takahashi, M; Narita, E; Shimooka, S

    1989-01-01

    Growing human offsprings are creatures that communicate by language. If rapidly growing children lose their deciduous teeth very early in life, their language and pronunciation functions may be seriously affected. The authors conducted a series of tests to find how the voice changes when deciduous teeth are extracted. The results may be summarized as follows. 1. There was no significant difference in the formants of vowels on "a-gyo", the first line of the Japanese syllabary, but an appreciable difference was recognized between children (four to six years old) with missing anterior teeth and posterior teeth when there were consonants before and after these vowels. 2. In the formants of the vowels, there was a marked difference in the vowel "i" when children were fitted with no appliance. 3. The strength of voice components in each frequency range was compared between children with missing anterior teeth and posterior teeth. It differed widely in "o ka a sa n" (which means "Mother") and "a-gyo", when children were fitted with no appliance. These findings indicate that the pronunciation of "o ka a sa n" and "a-gyo" can be recovered to some extent if the children are provided with an appliance. However, a sound analysis indicates that their pronunciation ability of sounds on "ka-gyo", "sa-gyo" and "ta-gyo" (the second, third and fourth lines of the Japanese syllabary) can hardly be fully recovered.

  15. Wormhole inspired by non-commutative geometry

    Energy Technology Data Exchange (ETDEWEB)

    Rahaman, Farook, E-mail: rahaman@iucaa.ernet.in [Department of Mathematics, Jadavpur University, Kolkata 700032, West Bengal (India); Karmakar, Sreya, E-mail: sreya.karmakar@gmail.com [Department of Physics, Calcutta Institute of Engineering and Management, Kolkata 700040, West Bengal (India); Karar, Indrani, E-mail: indrani.karar08@gmail.com [Department of Mathematics, Saroj Mohan Institute of Technology, Guptipara, West Bengal (India); Ray, Saibal, E-mail: saibal@iucaa.ernet.in [Department of Physics, Government College of Engineering & Ceramic Technology, Kolkata 700010, West Bengal (India)

    2015-06-30

    In the present Letter we search for a new wormhole solution inspired by noncommutative geometry with the additional condition of allowing conformal Killing vectors (CKV). A special aspect of noncommutative geometry is that it replaces point-like structures of gravitational sources with smeared objects under Gaussian distribution. However, the purpose of this letter is to obtain wormhole solutions with noncommutative geometry as a background where we consider a point-like structure of gravitational object without smearing effect. It is found through this investigation that wormhole solutions exist in this Lorentzian distribution with viable physical properties.

  16. Digital and discrete geometry theory and algorithms

    CERN Document Server

    Chen, Li

    2014-01-01

    This book provides comprehensive coverage of the modern methods for geometric problems in the computing sciences. It also covers concurrent topics in data sciences including geometric processing, manifold learning, Google search, cloud data, and R-tree for wireless networks and BigData.The author investigates digital geometry and its related constructive methods in discrete geometry, offering detailed methods and algorithms. The book is divided into five sections: basic geometry; digital curves, surfaces and manifolds; discretely represented objects; geometric computation and processing; and a

  17. Wormhole inspired by non-commutative geometry

    Directory of Open Access Journals (Sweden)

    Farook Rahaman

    2015-06-01

    Full Text Available In the present Letter we search for a new wormhole solution inspired by noncommutative geometry with the additional condition of allowing conformal Killing vectors (CKV. A special aspect of noncommutative geometry is that it replaces point-like structures of gravitational sources with smeared objects under Gaussian distribution. However, the purpose of this letter is to obtain wormhole solutions with noncommutative geometry as a background where we consider a point-like structure of gravitational object without smearing effect. It is found through this investigation that wormhole solutions exist in this Lorentzian distribution with viable physical properties.

  18. Information geometry near randomness and near independence

    CERN Document Server

    Arwini, Khadiga A

    2008-01-01

    This volume will be useful to practising scientists and students working in the application of statistical models to real materials or to processes with perturbations of a Poisson process, a uniform process, or a state of independence for a bivariate process. We use information geometry to provide a common differential geometric framework for a wide range of illustrative applications including amino acid sequence spacings in protein chains, cryptology studies, clustering of communications and galaxies, cosmological voids, coupled spatial statistics in stochastic fibre networks and stochastic porous media, quantum chaology. Introduction sections are provided to mathematical statistics, differential geometry and the information geometry of spaces of probability density functions.

  19. Fractal geometry mathematical foundations and applications

    CERN Document Server

    Falconer, Kenneth

    2013-01-01

    The seminal text on fractal geometry for students and researchers: extensively revised and updated with new material, notes and references that reflect recent directions. Interest in fractal geometry continues to grow rapidly, both as a subject that is fascinating in its own right and as a concept that is central to many areas of mathematics, science and scientific research. Since its initial publication in 1990 Fractal Geometry: Mathematical Foundations and Applications has become a seminal text on the mathematics of fractals.  The book introduces and develops the general theory and applica

  20. Differential geometry and topology of curves

    CERN Document Server

    Animov, Yu

    2001-01-01

    Differential geometry is an actively developing area of modern mathematics. This volume presents a classical approach to the general topics of the geometry of curves, including the theory of curves in n-dimensional Euclidean space. The author investigates problems for special classes of curves and gives the working method used to obtain the conditions for closed polygonal curves. The proof of the Bakel-Werner theorem in conditions of boundedness for curves with periodic curvature and torsion is also presented. This volume also highlights the contributions made by great geometers. past and present, to differential geometry and the topology of curves.

  1. Introduction into integral geometry and stereology

    DEFF Research Database (Denmark)

    Kiderlen, Markus

    This text is the extended version of two talks held at the Summer Academy Stochastic Geometry, Spatial Statistics and Random Fields in the Soellerhaus, Germany, in September 2009. It forms (with slight modifications) a chapter of the Springer lecture notes Lectures on Stochastic Geometry, Spatial...... Statistics and Random Fields and is a self-containing introduction into integral geometry and its applications in stereology. The most important integral geometric tools for stereological applications are kinematic formulas and results of Blaschke-Petkantschin type. Therefore, Crofton's formula...

  2. Post-traumatic complications of severe luxations and replanted teeth.

    Science.gov (United States)

    Rocha Lima, Thiago Farias; Nagata, Juliana Yuri; de Souza-Filho, Francisco José; de Jesus Soares, Adriana

    2015-01-01

    The aim of this study was to evaluate the main post-traumatic complications of severe luxation and replanted teeth using clinical and radiographic analyses. Eighty-three patients aged between 7 and 55 years old presenting 180 traumatized teeth that suffered extrusive luxation (n=67), lateral luxation (n=69), intrusive luxation (n=10) and tooth avulsion (n=34) followed by replantation were evaluated. The follow-up period was 24 months. The complications examined were: pulp canal obliteration, pulp necrosis and root resorption (infammatory and replacement). Furthermore, the relationship between time elapsed before receiving dental attendance and development of infammatory resorption was observed. Pulp necrosis was the main complication, occurring in 147 teeth (82.7%). All of the teeth that suffered intrusive luxation and tooth avulsion were diagnosed with pulp necrosis, with significant difference in comparison with another traumas (pcases and replacement resorption was more related to tooth replantation (94.1%), showing significant prevalence among tooth luxations (pdental trauma (Odds ratio test). It may be concluded that pulp necrosis was the main post-traumatic complication observed in traumatized teeth and that delay in seeking treatment may damage the prognosis of severe luxation and replanted teeth. Clinical studies describing the main complications that may affect traumatized teeth present great relevance to make the population aware of the importance of seeking immediate treatment and to alert the professional to the need for follow-up. When traumatic injuries are diagnosed and treated early, post-traumatic complications may be controlled, allowing conservation of the tooth in oral cavity.

  3. Influence of oral health behavior and sociodemographic factors on remaining teeth in Korean adults

    Science.gov (United States)

    Song, In-Seok; Han, Kyungdo; Choi, Yeon-Jo; Ryu, Jae-Jun; Park, Jun-Beom

    2016-01-01

    Abstract In this study, the number and location of remaining teeth were analyzed according to sociodemographic variables, anthropometric measurements, and oral health behavior patterns. The hypothesis was that the number and location of remaining teeth would be affected by oral health behavior and by sociodemographic factors, such as education levels, household income, and urban/rural residency. This nationwide cross-sectional study was performed with a total of 36,026 representative Korean adults aged 19 and older. The data were taken from the 2012–2012 Korea National Health and Nutrition Examination Survey. Men had, on average, significantly more remaining teeth than women did. Women brushed their teeth more often than men per day and were more likely to brush their teeth after meals. The participants with higher education levels or household income had significantly more remaining teeth; the number of daily tooth brushing was positively associated with the number of remaining teeth; urban residents had significantly more remaining teeth than rural residents; and elderly adults had fewer remaining teeth than younger adults had (all with P teeth than maxillary teeth, but among molars, they had more maxillary teeth than mandibular teeth. Elementary graduates with low household income had fewer remaining teeth than did university graduates with high household income (P teeth than anterior teeth compared to those with low socioeconomic status. The participants who brushed their teeth fewer times per day, those with low household incomes and/or education levels, and those who lived in rural districts had significantly higher prevalence of tooth loss than did other groups in Korean adults. Participants had more anterior and premolar teeth on mandible, but they had more molars on maxilla. In addition, participants with high socioeconomic status were more likely to lose their molar teeth than anterior teeth compared to those with low socioeconomic status. PMID

  4. Structure analysis for plane geometry figures

    Science.gov (United States)

    Feng, Tianxiao; Lu, Xiaoqing; Liu, Lu; Li, Keqiang; Tang, Zhi

    2013-12-01

    As there are increasing numbers of digital documents for education purpose, we realize that there is not a retrieval application for mathematic plane geometry images. In this paper, we propose a method for retrieving plane geometry figures (PGFs), which often appear in geometry books and digital documents. First, detecting algorithms are applied to detect common basic geometry shapes from a PGF image. Based on all basic shapes, we analyze the structural relationships between two basic shapes and combine some of them to a compound shape to build the PGF descriptor. Afterwards, we apply matching function to retrieve candidate PGF images with ranking. The great contribution of the paper is that we propose a structure analysis method to better describe the spatial relationships in such image composed of many overlapped shapes. Experimental results demonstrate that our analysis method and shape descriptor can obtain good retrieval results with relatively high effectiveness and efficiency.

  5. Gravity, Cartan geometry, and idealized waywisers

    CERN Document Server

    Westman, H F

    2012-01-01

    The primary aim of this paper is to provide a simple and concrete interpretation of Cartan geometry by pointing out that it is nothing but the mathematics of idealized waywisers. Waywisers, also called hodometers, are instruments traditionally used to measure distances. The mathematical representation of an idealized waywiser consists of a choice of symmetric space called a {\\em model space} and represents the `wheel' of the idealized waywiser. The geometry of a manifold is then completely characterized by a pair of variables $\\{V^A(x),A^{AB}(x)\\}$, each of which admit simple interpretations: $V^A$ is the point of contact between the waywiser's idealized wheel and the manifold whose geometry one wishes to characterize, and $A^{AB}=A_\\mu^{\\ AB}dx^\\mu$ is a connection one-form dictating how much the idealized wheel of the waywiser has rotated when rolled along the manifold. The familiar objects from differential geometry (e.g. metric $g_{\\mu\

  6. Geometry, structure and randomness in combinatorics

    CERN Document Server

    Nešetřil, Jaroslav; Pellegrini, Marco

    2014-01-01

    This book collects some surveys on current trends in discrete mathematics and discrete geometry. The areas covered include:  graph representations, structural graphs theory, extremal graph theory, Ramsey theory and constrained satisfaction problems.

  7. Homological mirror symmetry and tropical geometry

    CERN Document Server

    Catanese, Fabrizio; Kontsevich, Maxim; Pantev, Tony; Soibelman, Yan; Zharkov, Ilia

    2014-01-01

    The relationship between Tropical Geometry and Mirror Symmetry goes back to the work of Kontsevich and Y. Soibelman (2000), who applied methods of non-archimedean geometry (in particular, tropical curves) to Homological Mirror Symmetry. In combination with the subsequent work of Mikhalkin on the “tropical” approach to Gromov-Witten theory, and the work of Gross and Siebert, Tropical Geometry has now become a powerful tool. Homological Mirror Symmetry is the area of mathematics concentrated around several categorical equivalences connecting symplectic and holomorphic (or algebraic) geometry. The central ideas first appeared in the work of Maxim Kontsevich (1993). Roughly speaking, the subject can be approached in two ways: either one uses Lagrangian torus fibrations of Calabi-Yau manifolds (the so-called Strominger-Yau-Zaslow picture, further developed by Kontsevich and Soibelman) or one uses Lefschetz fibrations of symplectic manifolds (suggested by Kontsevich and further developed by Seidel). Tropical Ge...

  8. Track Geometry Measurement System Software Manual

    Science.gov (United States)

    1978-04-01

    The Track Geometry Measurement System (TGMS) was developed through the United States Department of Transportation's, Urban Mass Transportation Administration by the Transportation Systems Center in Cambridge, Massachusetts under its Test and Evaluati...

  9. 10th China-Japan Geometry Conference

    CERN Document Server

    Miyaoka, Reiko; Tang, Zizhou; Zhang, Weiping

    2016-01-01

    Since the year 2000, we have witnessed several outstanding results in geometry that have solved long-standing problems such as the Poincaré conjecture, the Yau–Tian–Donaldson conjecture, and the Willmore conjecture. There are still many important and challenging unsolved problems including, among others, the Strominger–Yau–Zaslow conjecture on mirror symmetry, the relative Yau–Tian–Donaldson conjecture in Kähler geometry, the Hopf conjecture, and the Yau conjecture on the first eigenvalue of an embedded minimal hypersurface of the sphere. For the younger generation to approach such problems and obtain the required techniques, it is of the utmost importance to provide them with up-to-date information from leading specialists. The geometry conference for the friendship of China and Japan has achieved this purpose during the past 10 years. Their talks deal with problems at the highest level, often accompanied with solutions and ideas, which extend across various fields in Riemannian geometry, sympl...

  10. The Soap-Bubble-Geometry Contest.

    Science.gov (United States)

    Morgan, Frank; Melnick, Edward R.; Nicholson, Ramona

    1997-01-01

    Presents an activity on soap-bubble geometry using a guessing contest, explanations, and demonstrations that allow students to mesh observation and mathematical reasoning to discover that mathematics is much more than just number crunching. (ASK)

  11. ARC Code TI: Geometry Manipulation Protocol (GMP)

    Data.gov (United States)

    National Aeronautics and Space Administration — The Geometry Manipulation Protocol (GMP) is a library which serializes datatypes between XML and ANSI C data structures to support CFD applications. This library...

  12. Quasi-crystalline geometry for architectural structures

    DEFF Research Database (Denmark)

    Weizierl, Barbara; Wester, Ture

    2001-01-01

    . The purpose of the paper is to investigate some possibilities for the application of Quasi-Crystal geometry for structures in architecture. The basis for the investigations is A: to use the Golden Cubes (the two different hexahedra consisting of rhombic facets where the length of the diagonals has the Golden......Artikel på CD-Rom 8 sider. The quasi-crystal (QC) type of material was discovered in 1983 by Dan Schechtman from Technion, Haifa. This new crystalline structure of material broke totally with the traditional conception of crystals and geometry introducing non-periodic close packing of cells...... ratio) as basic elements for aperiodic 3D geometries and B: to raise aperiodic Penrose tilings and its binary substitutions from their 2D basis into 3D QC geometries and describe the structural behaviour for these spatial configurations....

  13. Extracting Entanglement Geometry from Quantum States

    Science.gov (United States)

    Hyatt, Katharine; Garrison, James R.; Bauer, Bela

    2017-10-01

    Tensor networks impose a notion of geometry on the entanglement of a quantum system. In some cases, this geometry is found to reproduce key properties of holographic dualities, and subsequently much work has focused on using tensor networks as tractable models for holographic dualities. Conventionally, the structure of the network—and hence the geometry—is largely fixed a priori by the choice of the tensor network ansatz. Here, we evade this restriction and describe an unbiased approach that allows us to extract the appropriate geometry from a given quantum state. We develop an algorithm that iteratively finds a unitary circuit that transforms a given quantum state into an unentangled product state. We then analyze the structure of the resulting unitary circuits. In the case of noninteracting, critical systems in one dimension, we recover signatures of scale invariance in the unitary network, and we show that appropriately defined geodesic paths between physical degrees of freedom exhibit known properties of a hyperbolic geometry.

  14. Algebra, Geometry and Mathematical Physics Conference

    CERN Document Server

    Paal, Eugen; Silvestrov, Sergei; Stolin, Alexander

    2014-01-01

    This book collects the proceedings of the Algebra, Geometry and Mathematical Physics Conference, held at the University of Haute Alsace, France, October 2011. Organized in the four areas of algebra, geometry, dynamical symmetries and conservation laws and mathematical physics and applications, the book covers deformation theory and quantization; Hom-algebras and n-ary algebraic structures; Hopf algebra, integrable systems and related math structures; jet theory and Weil bundles; Lie theory and applications; non-commutative and Lie algebra and more. The papers explore the interplay between research in contemporary mathematics and physics concerned with generalizations of the main structures of Lie theory aimed at quantization, and discrete and non-commutative extensions of differential calculus and geometry, non-associative structures, actions of groups and semi-groups, non-commutative dynamics, non-commutative geometry and applications in physics and beyond. The book benefits a broad audience of researchers a...

  15. Robot Geometry and the High School Curriculum.

    Science.gov (United States)

    Meyer, Walter

    1988-01-01

    Description of the field of robotics and its possible use in high school computational geometry classes emphasizes motion planning exercises and computer graphics displays. Eleven geometrical problems based on robotics are presented along with the correct solutions and explanations. (LRW)

  16. Kerr geometry in f(T) gravity

    Energy Technology Data Exchange (ETDEWEB)

    Bejarano, Cecilia; Guzman, Maria Jose [Instituto de Astronomia y Fisica del Espacio (IAFE, CONICET-UBA), Buenos Aires (Argentina); Ferraro, Rafael [Instituto de Astronomia y Fisica del Espacio (IAFE, CONICET-UBA), Buenos Aires (Argentina); Universidad de Buenos Aires, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina)

    2015-02-01

    Null tetrads are shown to be a valuable tool in teleparallel theories of modified gravity. We use them to prove that Kerr geometry remains a solution for a wide family of f(T) theories of gravity. (orig.)

  17. The geometry of René Descartes

    CERN Document Server

    Descartes, René

    1954-01-01

    The great work that founded analytical geometry. Includes the original French text, Descartes' own diagrams, and the definitive Smith-Latham translation. "The greatest single step ever made in the progress of the exact sciences." - John Stuart Mill.

  18. The elements of non-Euclidean geometry

    CERN Document Server

    Sommerville, D MY

    2012-01-01

    Renowned for its lucid yet meticulous exposition, this classic allows students to follow the development of non-Euclidean geometry from a fundamental analysis of the concept of parallelism to more advanced topics. 1914 edition. Includes 133 figures.

  19. Tame geometry with application in smooth analysis

    CERN Document Server

    Yomdin, Yosef

    2004-01-01

    The Morse-Sard theorem is a rather subtle result and the interplay between the high-order analytic structure of the mappings involved and their geometry rarely becomes apparent. The main reason is that the classical Morse-Sard theorem is basically qualitative. This volume gives a proof and also an "explanation" of the quantitative Morse-Sard theorem and related results, beginning with the study of polynomial (or tame) mappings. The quantitative questions, answered by a combination of the methods of real semialgebraic and tame geometry and integral geometry, turn out to be nontrivial and highly productive. The important advantage of this approach is that it allows the separation of the role of high differentiability and that of algebraic geometry in a smooth setting: all the geometrically relevant phenomena appear already for polynomial mappings. The geometric properties obtained are "stable with respect to approximation", and can be imposed on smooth functions via polynomial approximation.

  20. Evaluation of the Dentistry course of UNIVILLE students’ knowledge about the use of the extracted teeth in the graduation and the teeth bank

    OpenAIRE

    Débora ZUCCO; Renata KOBE; Fabre, Caroline; Luciano MADEIRA; Flares BARATTO FILHO

    2006-01-01

    The aim of this study was, through a questionnaire, evaluate the levelof knowledge of the students from graduation in Dentistry course –UNIVILLE –, about the teeth bank: its activities and functioning,biosecutity in teeth manipulation and, especially, to find out the reason why the students do not donate spontaneously extracted teeth to the bank.A questionnaire was elaborated and applied to the studentsfrom the first to the fifth year of graduation with pertinent questions about the teeth ba...