WorldWideScience

Sample records for arrests tooth development

  1. First permanent molar root development arrest associated with compound odontoma.

    Science.gov (United States)

    Gunda, Sachin A; Patil, Anil; Varekar, Aniruddha

    2013-07-04

    Trauma or infection to the primary tooth may have deleterious effects on the underlying developing tooth buds. Anatomically the root apices of primary teeth are in close proximity to the developing permanent tooth buds; hence spread of infection originating from pulp necrosis of primary tooth may not only affect the underlying tooth bud but may also affect the adjacent tooth buds. The extent of malformation depends on the developmental stage of tooth or the age of patient. Presented here is a rare case of complete arrest of maxillary first permanent molar root growth due to spread of periapical infection originating from second primary molar leading to failure of its eruption and finally extraction. Histopathlogical analysis revealed compound odontoma associated with maxillary first permanent molar.

  2. Hedgehog signaling is required at multiple stages of zebrafish tooth development

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    Stock David W

    2010-11-01

    Full Text Available Abstract Background The accessibility of the developing zebrafish pharyngeal dentition makes it an advantageous system in which to study many aspects of tooth development from early initiation to late morphogenesis. In mammals, hedgehog signaling is known to be essential for multiple stages of odontogenesis; however, potential roles for the pathway during initiation of tooth development or in later morphogenesis are incompletely understood. Results We have identified mRNA expression of the hedgehog ligands shha and the receptors ptc1 and ptc2 during zebrafish pharyngeal tooth development. We looked for, but did not detect, tooth germ expression of the other known zebrafish hedgehog ligands shhb, dhh, ihha, or ihhb, suggesting that as in mammals, only Shh participates in zebrafish tooth development. Supporting this idea, we found that morphological and gene expression evidence of tooth initiation is eliminated in shha mutant embryos, and that morpholino antisense oligonucleotide knockdown of shha, but not shhb, function prevents mature tooth formation. Hedgehog pathway inhibition with the antagonist compound cyclopamine affected tooth formation at each stage in which we applied it: arresting development at early stages and disrupting mature tooth morphology when applied later. These results suggest that hedgehog signaling is required continuously during odontogenesis. In contrast, over-expression of shha had no effect on the developing dentition, possibly because shha is normally extensively expressed in the zebrafish pharyngeal region. Conclusion We have identified previously unknown requirements for hedgehog signaling for early tooth initiation and later morphogenesis. The similarity of our results with data from mouse and other vertebrates suggests that despite gene duplication and changes in the location of where teeth form, the roles of hedgehog signaling in tooth development have been largely conserved during evolution.

  3. Developing a biomimetic tooth bud model.

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    Smith, Elizabeth E; Zhang, Weibo; Schiele, Nathan R; Khademhosseini, Ali; Kuo, Catherine K; Yelick, Pamela C

    2017-01-08

    A long-term goal is to bioengineer, fully functional, living teeth for regenerative medicine and dentistry applications. Biologically based replacement teeth would avoid insufficiencies of the currently used dental implants. Using natural tooth development as a guide, a model was fabricated using post-natal porcine dental epithelial (pDE), porcine dental mesenchymal (pDM) progenitor cells, and human umbilical vein endothelial cells (HUVEC) encapsulated within gelatin methacrylate (GelMA) hydrogels. Previous publications have shown that post-natal DE and DM cells seeded onto synthetic scaffolds exhibited mineralized tooth crowns composed of dentin and enamel. However, these tooth structures were small and formed within the pores of the scaffolds. The present study shows that dental cell-encapsulated GelMA constructs can support mineralized dental tissue formation of predictable size and shape. Individually encapsulated pDE or pDM cell GelMA constructs were analysed to identify formulas that supported pDE and pDM cell attachment, spreading, metabolic activity, and neo-vasculature formation with co-seeded endothelial cells (HUVECs). GelMa constructs consisting of pDE-HUVECS in 3% GelMA and pDM-HUVECs within 5% GelMA supported dental cell differentiation and vascular mineralized dental tissue formation in vivo. These studies are the first to demonstrate the use of GelMA hydrogels to support the formation of post-natal dental progenitor cell-derived mineralized and functionally vascularized tissues of specified size and shape. These results introduce a novel three-dimensional biomimetic tooth bud model for eventual bioengineered tooth replacement teeth in humans. Copyright © 2017 John Wiley & Sons, Ltd.

  4. Bivalent histone modifications during tooth development

    Institute of Scientific and Technical Information of China (English)

    Li-Wei Zheng; Bin-Peng Zhang; Ruo-Shi Xu; Xin Xu; Ling Ye; Xue-Dong Zhou

    2014-01-01

    Histone methylation is one of the most widely studied post-transcriptional modifications. It is thought to be an important epigenetic event that is closely associated with cell fate determination and differentiation. To explore the spatiotemporal expression of histone H3 lysine 4 trimethylation (H3K4me3) and histone H3 lysine 27 trimethylation (H3K27me3) epigenetic marks and methylation or demethylation transferases in tooth organ development, we measured the expression of SET7, EZH2, KDM5B and JMJD3 via immunohistochemistry and quantitative polymerase chain reaction (qPCR) analysis in the first molar of BALB/c mice embryos at E13.5, E15.5, E17.5, P0 and P3, respectively. We also measured the expression of H3K4me3 and H3K27me3 with immunofluorescence staining. During murine tooth germ development, methylation or demethylation transferases were expressed in a spatial–temporal manner. The bivalent modification characterized by H3K4me3 and H3K27me3 can be found during the tooth germ development, as shown by immunofluorescence. The expression of SET7, EZH2 as methylation transferases and KDM5B and JMJD3 as demethylation transferases indicated accordingly with the expression of H3K4me3 and H3K27me3 respectively to some extent. The bivalent histone may play a critical role in tooth organ development via the regulation of cell differentiation.

  5. Fate of HERS during Tooth Root Development

    OpenAIRE

    HUANG, XIAOFENG; BRINGAS, PABLO; Slavkin, Harold C.; Chai, Yang

    2009-01-01

    Tooth root development begins after the completion of crown formation in mammals. Previous studies have shown that Hertwig's epithelial root sheath (HERS) plays an important role in root development, but the fate of HERS has remained unknown. In order to investigate the morphological fate and analyze the dynamic movement of HERS cells in vivo, we generated K14-Cre;R26R mice. HERS cells are detectable on the surface of the root throughout root formation and do not disappear. Most of the HERS c...

  6. Fate of developing tooth buds located in relation to mandibular fractures in three infancy cases.

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    Yamamoto, Kazuhiko; Matsusue, Yumiko; Murakami, Kazuhiro; Horita, Satoshi; Matsubara, Yuri; Kuraki, Miho; Kurihara, Miyako; Imai, Yuichiro; Sugiura, Tsutomu; Kirita, Tadaaki

    2010-08-01

    The fate of developing tooth buds located in relation to mandibular fractures was investigated in three infancy cases. Three infants, 2 girls and a boy, aged from 1 year and 5-months old to 2 years and 6-months old, were treated for dislocated mandibular fracture in the symphyseal region by manual reduction and fixation with a thermoforming splint and circumferential wiring under general anesthesia. Fracture healing was uneventful in all cases. A few years later, no obvious deformity of the jaw or malocclusion was observed; however, malformation of the crown was found in one of the permanent teeth on the fracture line in the first case. In the second case, no abnormality was observed in one of the permanent teeth on the fracture line, but the effect on the other tooth could not be evaluated due to abnormality of the tooth probably not related to the injury. In the third case, root formation was arrested in one of the permanent teeth on the fracture line and the tooth was lost early after eruption. The development of tooth buds on the fracture line is not predictable and therefore, should be monitored by regular follow up.

  7. Antagonistic Functions of USAG-1 and RUNX2 during Tooth Development

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    Togo, Yumiko; Takahashi, Katsu; Saito, Kazuyuki; Kiso, Honoka; Tsukamoto, Hiroko; Huang, Boyen; Yanagita, Motoko; Sugai, Manabu; Harada, Hidemitsu; Komori, Toshihisa; Shimizu, Akira; MacDougall, Mary; Bessho, Kazuhisa

    2016-01-01

    Supernumerary teeth and tooth agenesis are common morphological anomalies in humans. We previously obtained evidence that supernumerary maxillary incisors form as a result of the successive development of the rudimentary maxillary incisor tooth germ in Usag-1 null mice. The development of tooth germs is arrested in Runx2 null mice, and such mice also exhibit lingual epithelial buds associated with the upper molars and incisors. The aim of this study is to investigate the potential crosstalk between Usag-1 and Runx2 during tooth development. In the present study, three interesting phenomena were observed in double null Usag-1-/-/Runx2-/- mice: the prevalence of supernumerary teeth was lower than in Usag-1 null mice; tooth development progressed further compared than in Runx2 null mice; and the frequency of molar lingual buds was lower than in Runx2 null mice. Therefore, we suggest that RUNX2 and USAG-1 act in an antagonistic manner. The lingual bud was completely filled with odontogenic epithelial Sox2-positive cells in the Usag-1+/+/Runx2-/- mice, whereas almost no odontogenic epithelial Sox2-positive cells contributed to supernumerary tooth formation in the rudimentary maxillary incisors of the Usag-1-/-/Runx2+/+ mice. Our findings suggest that RUNX2 directly or indirectly prevents the differentiation and/or proliferation of odontogenic epithelial Sox2-positive cells. We hypothesize that RUNX2 inhibits the bone morphogenetic protein (BMP) and/or Wnt signaling pathways regulated by USAG-1, whereas RUNX2 expression is induced by BMP signaling independently of USAG-1. PMID:27518316

  8. Ultrastructure of basement membranes in developing shark tooth.

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    Sawada, T; Inoue, S

    2003-01-01

    Based on studies of the tooth of largely mammalian species, the dental basement membranes are shown to be specialized for various roles significant in the development and maintenance of the tooth. Comparative studies with the nonmammalian tooth will facilitate further clarification of the mechanisms of mammalian tooth formation. In this study, basement membranes of the shark tooth in successive developmental stages was ultrastructurally examined for elucidation of their roles in odontogenesis. Teeth of a shark, Cephaloscyllium umbratile, were processed for thin section electron microscopy. Throughout the developmental stages the lamina densa of the basement membrane was made up of a fine network of "cords," irregular anastomosing strands known to be the major component of mammalian basement membranes. In the presecretory stage of the shark tooth, dental papilla cells were immobilized for their differentiation into odontoblasts by means of the binding of their processes to numerous narrow extensions of the lamina densa of the inner dental epithelium. In the secretory stage, a number of cords of the widened lamina densa were extended towards and bound to tubular vesicles of the forming enameloid. During the mineralization stage, fragments of the degrading enameloid matrix appeared to be moving through the lamina densa to the epithelial cells for processing. In the maturation stage, half of the lamina densa facing the enameloid was mineralized forming an advancing edge of mineralization of the enameloid. It provided strong binding and smooth transition of organic to mineral phase which may allow transportation of substances across the phases for enameloid maturation in a way similar to that reported in the mammalian tooth. These observations indicate that basement membranes of the developing shark tooth, as those in the mammalian tooth, play various roles, including anchoring, firm binding, and possible mediation of the transport of substances that are known to be

  9. Modification of tooth development by heat shock protein 60

    Institute of Scientific and Technical Information of China (English)

    Tamas Papp; Angela Polyak; Krisztina Papp; Zoltan Meszar; Roza Zakany; Eva Meszar-Katona; Palne Terdik Tu nde; Chang Hwa Ham; Szabolcs Felszeghy

    2016-01-01

    Although several heat shock proteins have been investigated in relation to tooth development, no available information is available about the spatial and temporal expression pattern of heat shock protein 60 (Hsp 60). To characterize Hsp 60 expression in the structures of the developing tooth germ, we used Western blotting, immunohistochemistry and in situ hybridization. Hsp 60 was present in high amounts in the inner and outer enamel epithelia, enamel knot (EK) and stratum intermedium (SI). Hsp 60 also appeared in odontoblasts beginning in the bell stage. To obtain data on the possible effect of Hsp 60 on isolated lower incisors from mice, we performed in vitro culturing. To investigate the effect of exogenous Hsp 60 on the cell cycle during culturing, we used the 5-bromo-2- deoxyuridine (BrdU) incorporation test on dental cells. Exogenously administered Hsp 60 caused bluntness at the apical part of the 16.5-day-old tooth germs, but it did not influence the proliferation rate of dental cells. We identified the expression of Hsp 60 in the developing tooth germ, which was present in high concentrations in the inner and outer enamel epithelia, EK, SI and odontoblasts. High concentration of exogenous Hsp 60 can cause abnormal morphology of the tooth germ, but it did not influence the proliferation rate of the dental cells. Our results suggest that increased levels of Hsp 60 may cause abnormalities in the morphological development of the tooth germ and support the data on the significance of Hsp during the developmental processes.

  10. The development of complex tooth shape in reptiles

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    Oldrich eZahradnicek

    2014-02-01

    Full Text Available Reptiles have a diverse array of tooth shapes, from simple unicuspid to complex multicuspid teeth, reflecting functional adaptation to a variety of diets and eating styles. In addition to cusps, often complex longitudinal labial and lingual enamel crests are widespread and contribute to the final shape of reptile teeth. The simplest shaped unicuspid teeth have been found in piscivorous or carnivorous ancestors of recent diapsid reptiles and they are also present in some extant carnivores such as crocodiles and snakes. However, the ancestral tooth shape for squamate reptiles is thought to be bicuspid, indicating an insectivorous diet. The development of bicuspid teeth in lizards has recently been published, indicating that the mechanisms used to create cusps and crests are very distinct from those that shape cusps in mammals. Here, we introduce the large variety of tooth shapes found in lizards and compare the morphology and development of bicuspid, tricuspid and pentacuspid teeth, with the aim of understanding how such tooth shapes are generated. Next, we discuss whether the processes used to form such morphologies are conserved between divergent lizards and whether the underlying mechanisms share similarities with those of mammals. In particular, we will focus on the complex teeth of the chameleon, gecko, varanus and anole lizards using SEM and histology to compare the tooth crown morphology and embryonic development.

  11. Cell fate determination during tooth development and regeneration.

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    Mitsiadis, Thimios A; Graf, Daniel

    2009-09-01

    Teeth arise from sequential and reciprocal interactions between the oral epithelium and the underlying cranial neural crest-derived mesenchyme. Their formation involves a precisely orchestrated series of molecular and morphogenetic events, and gives us the opportunity to discover and understand the nature of the signals that direct cell fates and patterning. For that reason, it is important to elucidate how signaling factors work together in a defined number of cells to generate the diverse and precise patterned structures of the mature functional teeth. Over the last decade, substantial research efforts have been directed toward elucidating the molecular mechanisms that control cell fate decisions during tooth development. These efforts have contributed toward the increased knowledge on dental stem cells, and observation of the molecular similarities that exist between tooth development and regeneration.

  12. Arresting developments: trends in female arrests for domestic violence and proposed explanations.

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    Deleon-Granados, William; Wells, William; Binsbacher, Ruddyard

    2006-04-01

    This article represents an effort to generate more systematic and specified discussion on the topic of unintended consequences in the movement to decrease violence against women. In this case, the consequence is increases in female arrests for domestic violence. This article builds on recent discussions by first using a sample of data to examine felony domestic violence arrest rates for men and women. The data support the conclusion that domestic violence arrests of women have increased. Second, the article presents six explanations that are derived from existing literature. Although the authors do not offer empirical tests of these explanations, this presentation can play an important part in better understanding the outcomes of criminal justice policies that are aimed at increasing victim safety.

  13. Morphological study of tooth development in podoplanin-deficient mice

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    Takara, Kenyo; Maruo, Naoki; Oka, Kyoko; Kaji, Chiaki; Hatakeyama, Yuji; Sawa, Naruhiko; Kato, Yukinari; Yamashita, Junro; Kojima, Hiroshi; Sawa, Yoshihiko

    2017-01-01

    Podoplanin is a mucin-type highly O-glycosylated glycoprotein identified in several somatyic cells: podocytes, alveolar epithelial cells, lymphatic endothelial cells, lymph node stromal fibroblastic reticular cells, osteocytes, odontoblasts, mesothelial cells, glia cells, and others. It has been reported that podoplanin-RhoA interaction induces cytoskeleton relaxation and cell process stretching in fibroblastic cells and osteocytes, and that podoplanin plays a critical role in type I alveolar cell differentiation. It appears that podoplanin plays a number of different roles in contributing to cell functioning and growth by signaling. However, little is known about the functions of podoplanin in the somatic cells of the adult organism because an absence of podoplanin is lethal at birth by the respiratory failure. In this report, we investigated the tooth germ development in podoplanin-knockout mice, and the dentin formation in podoplanin-conditional knockout mice having neural crest-derived cells with deficiency in podoplanin by the Wnt1 promoter and enhancer-driven Cre recombinase: Wnt1-Cre;PdpnΔ/Δmice. In the Wnt1-Cre;PdpnΔ/Δmice, the tooth and alveolar bone showed no morphological abnormalities and grow normally, indicating that podoplanin is not critical in the development of the tooth and bone. PMID:28222099

  14. FGFs and BMP4 induce both Msx1-independent and Msx1-dependent signaling pathways in early tooth development.

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    Bei, M; Maas, R

    1998-11-01

    During early tooth development, multiple signaling molecules are expressed in the dental lamina epithelium and induce the dental mesenchyme. One signal, BMP4, has been shown to induce morphologic changes in dental mesenchyme and mesenchymal gene expression via Msx1, but BMP4 cannot substitute for all the inductive functions of the dental epithelium. To investigate the role of FGFs during early tooth development, we examined the expression of epithelial and mesenchymal Fgfs in wild-type and Msx1 mutant tooth germs and tested the ability of FGFs to induce Fgf3 and Bmp4 expression in wild-type and Msx1 mutant dental mesenchymal explants. Fgf8 expression is preserved in Msx1 mutant epithelium while that of Fgf3 is not detected in Msx1 mutant dental mesenchyme. Moreover, dental epithelium as well as beads soaked in FGF1, FGF2 or FGF8 induce Fgf3 expression in dental mesenchyme in an Msx1-dependent manner. These results indicate that, like BMP4, FGF8 constitutes an epithelial inductive signal capable of inducing the expression of downstream signaling molecules in dental mesenchyme via Msx1. However, the BMP4 and FGF8 signaling pathways are distinct. BMP4 cannot induce Fgf3 nor can FGFs induce Bmp4 expression in dental mesenchyme, even though both signaling molecules can induce Msx1 and Msx1 is necessary for Fgf3 and Bmp4 expression in dental mesenchyme. In addition, we have investigated the effects of FGFs and BMP4 on the distal-less homeobox genes Dlx1 and Dlx2 and we have clarified the relationship between Msx and Dlx gene function in the developing tooth. Dlx1,Dlx2 double mutants exhibit a lamina stage arrest in maxillary molar tooth development (Thomas B. L., Tucker A. S., Qiu M. , Ferguson C. A., Hardcastle Z., Rubenstein J. L. R. and Sharpe P. T. (1997) Development 124, 4811-4818). Although the maintenance of molar mesenchymal Dlx2 expression at the bud stage is Msx1-dependent, both the maintenance of Dlx1 expression and the initial activation of mesenchymal Dlx1

  15. Brazilian production development of class 2 polymeric surge arresters for transmission line application

    Energy Technology Data Exchange (ETDEWEB)

    Dellallibera, Adriano A. [Industria Eletromecanica Balestro, Mogi Mirim, SP (Brazil)], E-mail: adrianoad@balestro.com; Andrade, Antonio Donizetti de; Bezerra, Ana Cristina Guara; Duarte, Jose Vicente Pereira; Gois, Paulo Marcio Batista; Markiewicz, Rubens Leopoldo [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil)], Emails: andonize@cemig.com.br, anacris@cemig.com.br, vicente@cemig.com.br, pgois@cemig.com.br, rlmark@cemig.com.br

    2007-07-01

    This paper shows the steeps of Brazilian class 2 ZnO lightning surge arrester development and production, aiming to attend the goal of CEMIG transmission lines performance improvement against lightning discharges action. The description of CEMIG transmission lines performance, before and after the ZnO lightning arresters installation, the necessity of use of ZnO lightning surge arrester, the prototypes manufacture, tests, problems and solutions are presented. (author)

  16. Cadmium and zinc reversibly arrest development of Artemia larvae

    Energy Technology Data Exchange (ETDEWEB)

    Bagshaw, J.C.; Rafiee, P.; Matthews, C.O.; MacRae, T.H.

    1986-08-01

    Despite the widespread distribution of heavy metals such as cadmium and zinc in the environment and their well-known cytotoxicity and embryotoxicity in mammals, comparatively little is known about their effect on aquatic organisms, particularly invertebrates. Post-gastrula and early larval development of the brine shrimp, Artemia, present some useful advantages for studies of developmental aspects of environmental toxicology. Dormant encysted gastrulae, erroneously called brine shrimp eggs, can be obtained commercially and raised in the laboratory under completely defined conditions. Following a period of post-gastrula development within the cyst, pre-nauplius larvae emerge through a crack in the cyst shell. A few hours later, free-swimming nauplius larvae hatch. Cadmium is acutely toxic to both adults and nauplius larvae of Artemia, but the reported LC50s are as high as 10 mM, depending on larval age. In this paper the authors show that pre-nauplius larvae prior to hatching are much more sensitive to cadmium than are hatched nauplius larvae. At 0.1 ..mu..m, cadmium retards development and hatching of larvae; higher concentrations block hatching almost completely and thus are lethal. However, the larvae arrested at the emergence stage survive for 24 hours or more before succumbing to the effects of cadmium, and during this period the potentially lethal effect is reversible if the larvae are placed in cadmium-free medium. The effects of zinc parallel those of cadmium, although zinc is somewhat less toxic than cadmium at equal concentrations.

  17. Arrested Development of Audiovisual Speech Perception in Autism Spectrum Disorders

    Science.gov (United States)

    Stevenson, Ryan A.; Siemann, Justin K.; Woynaroski, Tiffany G.; Schneider, Brittany C.; Eberly, Haley E.; Camarata, Stephen M.; Wallace, Mark T.

    2013-01-01

    Atypical communicative abilities are a core marker of Autism Spectrum Disorders (ASD). A number of studies have shown that, in addition to auditory comprehension differences, individuals with autism frequently show atypical responses to audiovisual speech, suggesting a multisensory contribution to these communicative differences from their typically developing peers. To shed light on possible differences in the maturation of audiovisual speech integration, we tested younger (ages 6-12) and older (ages 13-18) children with and without ASD on a task indexing such multisensory integration. To do this, we used the McGurk effect, in which the pairing of incongruent auditory and visual speech tokens typically results in the perception of a fused percept distinct from the auditory and visual signals, indicative of active integration of the two channels conveying speech information. Whereas little difference was seen in audiovisual speech processing (i.e., reports of McGurk fusion) between the younger ASD and TD groups, there was a significant difference at the older ages. While TD controls exhibited an increased rate of fusion (i.e., integration) with age, children with ASD failed to show this increase. These data suggest arrested development of audiovisual speech integration in ASD. The results are discussed in light of the extant literature and necessary next steps in research. PMID:24218241

  18. Msx1 and Tbx2 antagonistically regulate Bmp4 expression during the bud-to-cap stage transition in tooth development.

    Science.gov (United States)

    Saadi, Irfan; Das, Pragnya; Zhao, Minglian; Raj, Lakshmi; Ruspita, Intan; Xia, Yan; Papaioannou, Virginia E; Bei, Marianna

    2013-07-01

    Bmp4 expression is tightly regulated during embryonic tooth development, with early expression in the dental epithelial placode leading to later expression in the dental mesenchyme. Msx1 is among several transcription factors that are induced by epithelial Bmp4 and that, in turn, are necessary for the induction and maintenance of dental mesenchymal Bmp4 expression. Thus, Msx1(-/-) teeth arrest at early bud stage and show loss of Bmp4 expression in the mesenchyme. Ectopic expression of Bmp4 rescues this bud stage arrest. We have identified Tbx2 expression in the dental mesenchyme at bud stage and show that this can be induced by epithelial Bmp4. We also show that endogenous Tbx2 and Msx1 can physically interact in mouse C3H10T1/2 cells. In order to ascertain a functional relationship between Msx1 and Tbx2 in tooth development, we crossed Tbx2 and Msx1 mutant mice. Our data show that the bud stage tooth arrest in Msx1(-/-) mice is partially rescued in Msx1(-/-);Tbx2(+/-) compound mutants. This rescue is accompanied by formation of the enamel knot (EK) and by restoration of mesenchymal Bmp4 expression. Finally, knockdown of Tbx2 in C3H10T1/2 cells results in an increase in Bmp4 expression. Together, these data identify a novel role for Tbx2 in tooth development and suggest that, following their induction by epithelial Bmp4, Msx1 and Tbx2 in turn antagonistically regulate odontogenic activity that leads to EK formation and to mesenchymal Bmp4 expression at the key bud-to-cap stage transition.

  19. Stem Cells in Tooth Development, Growth, Repair, and Regeneration.

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    Yu, Tian; Volponi, Ana Angelova; Babb, Rebecca; An, Zhengwen; Sharpe, Paul T

    2015-01-01

    Human teeth contain stem cells in all their mesenchymal-derived tissues, which include the pulp, periodontal ligament, and developing roots, in addition to the support tissues such as the alveolar bone. The precise roles of these cells remain poorly understood and most likely involve tissue repair mechanisms but their relative ease of harvesting makes teeth a valuable potential source of mesenchymal stem cells (MSCs) for therapeutic use. These dental MSC populations all appear to have the same developmental origins, being derived from cranial neural crest cells, a population of embryonic stem cells with multipotential properties. In rodents, the incisor teeth grow continuously throughout life, a feature that requires populations of continuously active mesenchymal and epithelial stem cells. The discrete locations of these stem cells in the incisor have rendered them amenable for study and much is being learnt about the general properties of these stem cells for the incisor as a model system. The incisor MSCs appear to be a heterogeneous population consisting of cells from different neural crest-derived tissues. The epithelial stem cells can be traced directly back in development to a Sox10(+) population present at the time of tooth initiation. In this review, we describe the basic biology of dental stem cells, their functions, and potential clinical uses.

  20. A simple rule governs the evolution and development of hominin tooth size.

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    Evans, Alistair R; Daly, E Susanne; Catlett, Kierstin K; Paul, Kathleen S; King, Stephen J; Skinner, Matthew M; Nesse, Hans P; Hublin, Jean-Jacques; Townsend, Grant C; Schwartz, Gary T; Jernvall, Jukka

    2016-02-25

    The variation in molar tooth size in humans and our closest relatives (hominins) has strongly influenced our view of human evolution. The reduction in overall size and disproportionate decrease in third molar size have been noted for over a century, and have been attributed to reduced selection for large dentitions owing to changes in diet or the acquisition of cooking. The systematic pattern of size variation along the tooth row has been described as a 'morphogenetic gradient' in mammal, and more specifically hominin, teeth since Butler and Dahlberg. However, the underlying controls of tooth size have not been well understood, with hypotheses ranging from morphogenetic fields to the clone theory. In this study we address the following question: are there rules that govern how hominin tooth size evolves? Here we propose that the inhibitory cascade, an activator-inhibitor mechanism that affects relative tooth size in mammals, produces the default pattern of tooth sizes for all lower primary postcanine teeth (deciduous premolars and permanent molars) in hominins. This configuration is also equivalent to a morphogenetic gradient, finally pointing to a mechanism that can generate this gradient. The pattern of tooth size remains constant with absolute size in australopiths (including Ardipithecus, Australopithecus and Paranthropus). However, in species of Homo, including modern humans, there is a tight link between tooth proportions and absolute size such that a single developmental parameter can explain both the relative and absolute sizes of primary postcanine teeth. On the basis of the relationship of inhibitory cascade patterning with size, we can use the size at one tooth position to predict the sizes of the remaining four primary postcanine teeth in the row for hominins. Our study provides a development-based expectation to examine the evolution of the unique proportions of human teeth.

  1. Developing the First Gapless ZnO Surge Arrester in the World

    Science.gov (United States)

    Hayashi, Masao; Kobayashi, Misao

    Metal Oxide Surge Arrester (MOSA) technology was first developed in Japan and improved. Original discovery was made by Matsushita Electric Industry Co., Ltd by a finding of some diode phenomenon. Meidensha Corporation applied it to high voltage grid system in Japan in 1975 as a reliable lightning protection device. Japanese MOSA manufactures played a leading role in world MOSA innovations and developments. The BIL has been standardized based on arrester protective characteristics. Due to MOSA, the product shift to MOSA occurred from the gapped type arresters (GTA) 35 years ago as GTA had many gap-related problems. The MOSA became a complete IEC standard (IEC60099-4-1991) taking 20 years from starting development. The MOSA now has a solid footprint in the world lightning protection space.

  2. Characterization of glycosaminoglycans during tooth development and mineralization in the axolotl, Ambystoma mexicanum.

    Science.gov (United States)

    Wistuba, J; Völker, W; Ehmcke, J; Clemen, G

    2003-10-01

    Glycosaminoglycans (GAGs) involved in the formation of the teeth of Ambystoma mexicanum were located and characterized with the cuprolinic blue (CB) staining method and transmission electron microscopy (TEM). Glycosaminoglycan-cuprolinic blue precipitates (GAGCB) were found in different compartments of the mineralizing tissue. Various populations of elongated GAGCB could be discriminated both according to their size and their preferential distribution in the extracellular matrix (ECM). GAGCB populations that differ in their composition could be attributed not only to the compartments of the ECM but also to different zones and to different tooth types (early-larval and transformed). Larger precipitates were only observed within the dentine matrix of the shaft of the early-larval tooth. The composition of the populations differed significantly between the regions of the transformed tooth: pedicel, shaft and dividing zone. In later stages of tooth formation, small-sized GAGCBs were seen as intracellular deposits in the ameloblasts. It is concluded that the composition of GAGCB populations seems to play a role in the mineralization processes during tooth development in A. mexicanum and influence qualitative characteristics of the mineral in different tooth types and zones, and it is suggested that GAGs might be resorbed by the enamel epithelium during the late phase of enamel formation.

  3. Comparison of Leaf Plastochron Index and Allometric Analyses of Tooth Development in Arabidopsis thaliana.

    Science.gov (United States)

    Groot; Meicenheimer

    2000-03-01

    Two methods of analyses were used to investigate tooth development in serrate (se) mutant and wild-type Columbia-1 (Col-1) Arabidopsis thaliana leaves. There were almost twice as many teeth with deeper sinuses and two orders of toothing on the margins of serrate compared with Columbia-1 leaves. The main objective of this study was to test three hypotheses relative to the source of polymorphism in tooth development: (i) Teeth share similar growth rates and initial sizes, but the deeper teeth are initiated earlier in leaf development. (ii) Teeth share similar timing of initiation and growth rates, but the deeper teeth have a larger initial size. (iii) Teeth share similar timing of initiation and initial sizes, but the deeper teeth have a faster growth rate. Leaf plastochron index (LPI) was used as the time variable for leaf development. Results showed teeth in se were initiated at -27 LPI, 15 plastochrons earlier than those of Col-1. Serrate leaf expansion was biphasic, with the early phase expanding at half the relative plastochron rate of the later phase, which equaled the constant relative expansion rate of Col-1 leaves. Allometric analyses of tooth development obscured the interactions between time of tooth and leaf initiation and the early phase of leaf expansion characteristic of serrate leaves and teeth. Timing of developmental events that allometric analysis obscured can be readily detected with the LPI as a developmental index.

  4. An evolutionary view on tooth development and replacement in wild Atlantic salmon (Salmo salar L.).

    Science.gov (United States)

    Huysseune, A; Witten, P E

    2008-01-01

    To gain an insight into the evolution of tooth replacement mechanisms, we studied the development of first-generation and replacement teeth on the dentary of wild Atlantic salmon (Salmo salar L.), a protacanthopterygian teleost, using serially sectioned heads of early posthatching stages as well as adults. First-generation teeth develop within the oral epithelium. The anlage of the replacement tooth is first seen as a placode-like thickening of the outer dental epithelium of the predecessor, at its lingual and caudal side. Ongoing development of the replacement tooth germ is characterized by the elaboration of a population of epithelial cells, termed here the middle dental epithelium, apposed to the inner dental epithelium on the lingual side of the tooth germ. Before the formation of the new successor, a single-layered outer dental epithelium segregates from the middle dental epithelium. The dental organs of the predecessor and the successor remain broadly interconnected. The absence of a discrete successional dental lamina in salmon stands in sharp contrast to what is observed in other teleosts, even those that share with salmon the extraosseous formation of replacement teeth. The mode of tooth replacement in Atlantic salmon displays several characters similar to those observed in the shark Squalus acanthias. To interpret similarities in tooth replacement between Atlantic salmon and chondrichthyans as a case of convergence, or to see them as a result of a heterochronic shift, requires knowledge on the replacement process in more basal actinopterygian lineages. The possibility that the middle dental epithelium functionally substitutes for a successional lamina, and could be a source of stem cells, whose descendants subsequently contribute to the placode of the new replacement tooth, needs to be explored.

  5. Cell cycle arrest by a gradient of Dpp signaling during Drosophila eye development

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    Bhattacharya Abhishek

    2010-03-01

    Full Text Available Abstract Background The secreted morphogen Dpp plays important roles in spatial regulation of gene expression and cell cycle progression in the developing Drosophila eye. Dpp signaling is required for timely cell cycle arrest ahead of the morphogenetic furrow as a prelude to differentiation, and is also important for eye disc growth. The dpp gene is expressed at multiple locations in the eye imaginal disc, including the morphogenetic furrow that sweeps across the eye disc as differentiation initiates. Results Studies of Brinker and Dad expression, and of Mad phosphorylation, establish that there is a gradient of Dpp signaling in the eye imaginal disc anterior to the morphogenetic furrow, predominantly in the anterior-posterior axis, and also Dpp signaling at the margins of the disc epithelium and in the dorsal peripodial membrane. Almost all signaling activity seems to spread through the plane of the epithelia, although peripodial epithelium cells can also respond to underlying disc cells. There is a graded requirement for Dpp signaling components for G1 arrest in the eye disc, with more stringent requirements further anteriorly where signaling is lower. The signaling level defines the cell cycle response, because elevated signaling through expression of an activated Thickveins receptor molecule arrested cells at more anterior locations. Very anterior regions of the eye disc were not arrested in response to activated receptor, however, and evidence is presented that expression of the Homothorax protein may contribute to this protection. By contrast to activated Thickveins, ectopic expression of processed Dpp leads to very high levels of Mad phosphorylation which appear to have non-physiological consequences. Conclusions G1 arrest occurs at a threshold level of Dpp signaling within a morphogen gradient in the anterior eye. G1 arrest is specific for one competent domain in the eye disc, allowing Dpp signaling to promote growth at earlier

  6. Plakophilin-1, a Novel Wnt Signaling Regulator, Is Critical for Tooth Development and Ameloblast Differentiation.

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    Kanako Miyazaki

    Full Text Available Tooth morphogenesis is initiated by reciprocal interactions between the ectoderm and neural crest-derived mesenchyme, and the Wnt signaling pathway is involved in this process. We found that Plakophilin (PKP1, which is associated with diseases such as ectodermal dysplasia/skin fragility syndrome, was highly expressed in teeth and skin, and was upregulated during tooth development. We hypothesized that PKP1 regulates Wnt signaling via its armadillo repeat domain in a manner similar to β-catenin. To determine its role in tooth development, we performed Pkp1 knockdown experiments using ex vivo organ cultures and cell cultures. Loss of Pkp1 reduced the size of tooth germs and inhibited dental epithelial cell proliferation, which was stimulated by Wnt3a. Furthermore, transfected PKP1-emerald green fluorescent protein was translocated from the plasma membrane to the nucleus upon stimulation with Wnt3a and LiCl, which required the PKP1 N terminus (amino acids 161 to 270. Localization of PKP1, which is known as an adhesion-related desmosome component, shifted to the plasma membrane during ameloblast differentiation. In addition, Pkp1 knockdown disrupted the localization of Zona occludens 1 in tight junctions and inhibited ameloblast differentiation; the two proteins were shown to directly interact by immunoprecipitation. These results implicate the participation of PKP1 in early tooth morphogenesis as an effector of canonical Wnt signaling that controls ameloblast differentiation via regulation of the cell adhesion complex.

  7. A model of growth restraints to explain the development and evolution of tooth shapes in mammals.

    Science.gov (United States)

    Osborn, Jeffrey W

    2008-12-07

    The problem investigated here is control of the development of tooth shape. Cells at the growing soft tissue interface between the ectoderm and mesoderm in a tooth anlage are observed to buckle and fold into a template for the shape of the tooth crown. The final shape is created by enamel secreted onto the folds. The pattern in which the folds develop is generally explained as a response to the pattern in which genes are locally expressed at the interface. This congruence leaves the problem of control unanswered because it does not explain how either pattern is controlled. Obviously, cells are subject to Newton's laws of motion so that mechanical forces and constraints must ultimately cause the movements of cells during tooth morphogenesis. A computer model is used to test the hypothesis that directional resistances to growth of the epithelial part of the interface could account for the shape into which the interface folds. The model starts with a single epithelial cell whose growth is constrained by 4 constant directional resistances (anterior, posterior, medial and lateral). The constraints force the growing epithelium to buckle and fold. By entering into the model different values for these constraints the modeled epithelium is induced to buckle and fold into the different shapes associated with the evolution of a human upper molar from that of a reptilian ancestor. The patterns and sizes of cusps and the sequences in which they develop are all correctly reproduced. The model predicts the changes in the 4 directional constraints necessary to develop and evolve from one tooth shape into another. I conclude more generally expressed genes that control directional resistances to growth, not locally expressed genes, may provide the information for the shape into which a tooth develops.

  8. Temporospatial tissue interactions regulating the regeneration of the enamel knot in the developing mouse tooth.

    Science.gov (United States)

    Cho, Sung-Won; Kim, Jae-Young; Cai, Jinglei; Lee, Jong-Min; Kim, Eun-Jung; Lee, Hyun-A; Yamamoto, Hitoshi; Jung, Han-Sung

    2007-02-01

    The enamel knot (EK), which is a transient signaling center in the tooth germ, regulates both the differential growth of the dental epithelium and the tooth shape. In this study, the regeneration of the EK was evaluated. The EK regions were removed from the E14 and E16 dental epithelia, and the remaining epithelia were recombined with their original dental mesenchymes. All these tooth germs could develop into calcified teeth after being transplanted into the kidney capsule for 3 weeks. One primary EK was regenerated earlier, and two or three secondary EKs were regenerated later in culture. When simply recombined without removing the EK, the tooth germ, which had four secondary EKs and four cuspal areas of the dental papilla, generated one primary EK first and subsequent secondary EKs. These results indicate that the patterning of the EK in all tooth germs always starts from a primary EK independent of the direct epithelial or mesenchymal control. This suggests that neither the dental epithelium nor the dental mesenchyme can dictate the pattern or number of the EK formation, but the interaction between the dental epithelium and the dental mesenchyme is essential for the regeneration and patterning of the EKs.

  9. Esthetic and endosurgical management of Turner's hypoplasia; a sequlae of trauma to developing tooth germ.

    Science.gov (United States)

    Bhushan, B A; Garg, S; Sharma, D; Jain, M

    2008-01-01

    Turner's hypoplasia usually manifests as a portion of missing or diminished enamel, generally affecting one or more permanent teeth in the oral cavity. A case report of 8 year old girl who met with trauma at 2 years of age leading to primary incisors being knocked out, reported after 6 years with complaint of pain and discharge in her anterior malformed teeth is discussed in this article. The permanent incisors erupted with dilacerated crown, root malformations and missing enamel. Further, patient developed sinus, lateral root pathology, tooth mobility and malocclusion in relation to affected teeth which were managed by esthetic, functional, endodontic and surgical procedure. Root canal treatment along with palatal contouring and esthetic restoration by light cure composite was performed on the tooth with crown dilaceration and sinus, where as surgical management was considered for the tooth with root malformation.

  10. Tooth development in Ambystoma mexicanum: phosphatase activities, calcium accumulation and cell proliferation in the tooth-forming tissues.

    Science.gov (United States)

    Wistuba, Joachim; Ehmcke, Jens; Clemen, Günter

    2003-06-01

    Prerequisites of tooth formation, cell proliferation in the tooth-forming tissues, calcium accumulation and the enzymatic activities of alkaline (ALP) and acid phosphatases (ACP) were investigated by immunohistochemical and histochemical methods in various developmental stages of the Mexican Axolotl, Ambystoma mexicanum. During the growth of replacement teeth, the tooth-forming tissues continually recruit cells from the surrounding regions. The basal layer of the oral epithelium, the dental lamina and sometimes even the outer enamel epithelium provide cells for the differentiated inner enamel epithelium, in which the active ameloblasts are localized. The differentiating odontoblasts are derived from proliferating cells situated basally to the replacement teeth in the mesenchymal tissue. When differentiation has started and the cells have become functional, proliferative activity can no longer be observed. Calcium is accumulated close to the site of mineralization in the inner enamel epithelium and in the odontoblasts as it is in mammals, elasmobranchii and teleostei. The activities of ACP and ALP related to the mineralization of the replacement teeth are separated spatially and not sequentially as they are in mammals. However, the results indicate a similar function of these enzymatic components in relation to tooth formation and maturation of mineral deposition. Most of the substantial processes related to tooth formation reported from other vertebrates occur in a manner similar to that in Ambystoma mexicanum, but there also seem to be basic mechanisms present that are realised in a unique way in this urodele.

  11. Risk factors for developing tooth sensitivity and gingival irritation associated with nightguard vital bleaching.

    Science.gov (United States)

    Leonard, R H; Haywood, V B; Phillips, C

    1997-08-01

    The purpose of this study was to determine risk factors in the development of tooth sensitivity and gingival irritation associated with the nightguard vital bleaching technique. The potential risk factors evaluated (sex, age, reported allergy, whitening solution, number of times the solution was changed daily [its usage pattern], and dental arch) were collected from the daily log form turned in by each of the 64 participants after completion of the 6-week lightening process. Also evaluated for each participant, from color slides, were tooth characteristics such as gingival recession, defective restorations, abfraction lesions, enamel-cementum abrasion, etc, and reported side effects. The generalized Mantel-Haenszel statistic was used to assess the association between the potential risk factors and the development of tooth sensitivity and/or gingival irritation. No statistical relationship existed between age, sex, allergy, tooth characteristics, or the dental arch lightened and the development of side effects. Initially, a statistically significant association existed between side effects and the whitening solution used. However, when the analysis was controlled for usage pattern, this relationship disappeared. Patients who changed the whitening solution more than once a day reported statistically significantly more side effects than did those who did not change the whitening solution during their usage time.

  12. Chick limbs with mouse teeth: an effective in vivo culture system for tooth germ development and analysis.

    Science.gov (United States)

    Koyama, Eiki; Wu, Changshan; Shimo, Tsuyoshi; Pacifici, Maurizio

    2003-01-01

    Mouse tooth germ development is currently studied by three main approaches: in wild-type and mutant mouse lines, after transplantation of tooth germs to ectopic sites, and in organ culture. The in vivo approaches are the most physiological but do not provide accessibility to tooth germs for further experimental manipulation. Organ cultures, although readily accessible, do not sustain full tooth germ development and are appropriate for short-term analysis. Thus, we sought to establish a new approach that would combine experimental accessibility with sustained development. We implanted fragments of embryonic day 12 mouse embryo first branchial arch containing early bud stage tooth germs into the lateral mesenchyme of day 4-5 chick embryo wing buds in ovo. Eggs were reincubated, and implanted tissues were examined by histochemistry and in situ hybridization over time. The tooth germs underwent seemingly normal growth, differentiation, and morphogenesis. They reached the cap, bell, and crown stages in approximately 3, 6, and 10 days, respectively, mimicking in a striking manner native temporal patterns. To examine mechanisms regulating tooth germ development, we first implanted tooth germ fragments, microinjected them with neutralizing antibodies to the key signaling molecule Sonic hedgehog (Shh), and examined them over time. Tooth germ development was markedly delayed, as revealed by poor morphogenesis and lack of mature ameloblasts and odontoblasts displaying characteristic traits such as an elongated cell shape, nuclear relocalization, and amelogenin gene expression. These phenotypic changes began to be reversed upon further incubation. The data show that the limb bud represents an effective, experimentally accessible as well as economical system for growth and analysis of developing tooth germs. The inhibitory effects of Shh neutralizing antibody treatment are discussed in relation to roles of this signaling pathway proposed by this and other groups previously.

  13. Development and evolution of dentition pattern and tooth order in the skates and rays (batoidea; chondrichthyes.

    Directory of Open Access Journals (Sweden)

    Charlie J Underwood

    Full Text Available Shark and ray (elasmobranch dentitions are well known for their multiple generations of teeth, with isolated teeth being common in the fossil record. However, how the diverse dentitions characteristic of elasmobranchs form is still poorly understood. Data on the development and maintenance of the dental patterning in this major vertebrate group will allow comparisons to other morphologically diverse taxa, including the bony fishes, in order to identify shared pattern characters for the vertebrate dentition as a whole. Data is especially lacking from the Batoidea (skates and rays, hence our objective is to compile data on embryonic and adult batoid tooth development contributing to ordering of the dentition, from cleared and stained specimens and micro-CT scans, with 3D rendered models. We selected species (adult and embryonic spanning phylogenetically significant batoid clades, such that our observations may raise questions about relationships within the batoids, particularly with respect to current molecular-based analyses. We include developmental data from embryos of recent model organisms Leucoraja erinacea and Raja clavata to evaluate the earliest establishment of the dentition. Characters of the batoid dentition investigated include alternate addition of teeth as offset successional tooth rows (versus single separate files, presence of a symphyseal initiator region (symphyseal tooth present, or absent, but with two parasymphyseal teeth and a restriction to tooth addition along each jaw reducing the number of tooth families, relative to addition of successor teeth within each family. Our ultimate aim is to understand the shared characters of the batoids, and whether or not these dental characters are shared more broadly within elasmobranchs, by comparing these to dentitions in shark outgroups. These developmental morphological analyses will provide a solid basis to better understand dental evolution in these important vertebrate groups as

  14. Development and evolution of dentition pattern and tooth order in the skates and rays (batoidea; chondrichthyes).

    Science.gov (United States)

    Underwood, Charlie J; Johanson, Zerina; Welten, Monique; Metscher, Brian; Rasch, Liam J; Fraser, Gareth J; Smith, Moya Meredith

    2015-01-01

    Shark and ray (elasmobranch) dentitions are well known for their multiple generations of teeth, with isolated teeth being common in the fossil record. However, how the diverse dentitions characteristic of elasmobranchs form is still poorly understood. Data on the development and maintenance of the dental patterning in this major vertebrate group will allow comparisons to other morphologically diverse taxa, including the bony fishes, in order to identify shared pattern characters for the vertebrate dentition as a whole. Data is especially lacking from the Batoidea (skates and rays), hence our objective is to compile data on embryonic and adult batoid tooth development contributing to ordering of the dentition, from cleared and stained specimens and micro-CT scans, with 3D rendered models. We selected species (adult and embryonic) spanning phylogenetically significant batoid clades, such that our observations may raise questions about relationships within the batoids, particularly with respect to current molecular-based analyses. We include developmental data from embryos of recent model organisms Leucoraja erinacea and Raja clavata to evaluate the earliest establishment of the dentition. Characters of the batoid dentition investigated include alternate addition of teeth as offset successional tooth rows (versus single separate files), presence of a symphyseal initiator region (symphyseal tooth present, or absent, but with two parasymphyseal teeth) and a restriction to tooth addition along each jaw reducing the number of tooth families, relative to addition of successor teeth within each family. Our ultimate aim is to understand the shared characters of the batoids, and whether or not these dental characters are shared more broadly within elasmobranchs, by comparing these to dentitions in shark outgroups. These developmental morphological analyses will provide a solid basis to better understand dental evolution in these important vertebrate groups as well as the

  15. Dental Stem Cell in Tooth Development and Advances of Adult Dental Stem Cell in Regenerative Therapies.

    Science.gov (United States)

    Tan, Jiali; Xu, Xin; Lin, Jiong; Fan, Li; Zheng, Yuting; Kuang, Wei

    2015-01-01

    Stem cell-based therapies are considered as a promising treatment for many clinical usage such as tooth regeneration, bone repairation, spinal cord injury, and so on. However, the ideal stem cell for stem cell-based therapy still remains to be elucidated. In the past decades, several types of stem cells have been isolated from teeth, including dental pulp stem cells (DPSCs), stem cells from human exfoliated deciduous teeth (SHED), periodontal ligament stem cells (PDLSCs), dental follicle progenitor stem cells (DFPCs) and stem cells from apical papilla (SCAP), which may be a good source for stem cell-based therapy in certain disease, especially when they origin from neural crest is considered. In this review, the specific characteristics and advantages of the adult dental stem cell population will be summarized and the molecular mechanisms of the differentiation of dental stem cell during tooth development will be also discussed.

  16. Tooth extraction

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007630.htm Tooth extraction To use the sharing features on this page, please enable JavaScript. A tooth extraction is a procedure to remove a tooth from ...

  17. Development of dental charts according to tooth development and eruption for Turkish children and young adults

    Energy Technology Data Exchange (ETDEWEB)

    Karadayl, Beytullah; Ozaslan, Abdi [University of Istanbul, Cerrahpasa Faculty of Medicine, Forensic Medicine Department, Istanbul (Turkey); Afsin, Hueseyin [University of Istanbul, Cerrahpasa Faculty of Medicine, Forensic Medicine Department, Istanbul (Turkey); Karadayi, Suekriye [Public Health Agency, Istanbul (Turkey)

    2014-06-15

    In this study, we aimed to develop dental charts for Turkish children and young adults of both genders within the age group of 4.5-22.5 years according to tooth mineralization and eruption in a format similar to that proposed by AlQahtani et al. In total, 753 digital panoramic radiographs from 350 males and 403 females were assessed. The permanent teeth were evaluated according to the classification system described by Demirjian et al. The eruption stage was assessed with Bengston's system, which was modified by AlQahtani et al at four points. Teeth generally developed earlier in females than in males. This was particularly notable in the age group of 5-14 years. However, this difference was usually visible in only one stage, not in all teeth. It has been determined that the mixed dentition period ended with the shedding of the second deciduous molars in both genders. The dental charts presented here included information that could be beneficial to dental clinicians in making appropriate diagnosis and planning orthodontic and surgical procedures. These charts also provided datasets for preliminary dental age estimation in Turkish children and young adults.

  18. Arrested development of abomasal trichostrongylid nematodes in lambs in a steppe environment (North-Eastern Algeria)

    Science.gov (United States)

    Meradi, Salah; Cabaret, Jacques; Bentounsi, Bourhane

    2016-01-01

    Arrested development of abomasal trichostrongylid nematodes was studied in 30 permanent grazing lambs on a large farm in the North-East of Algeria. The steppe climate has cold winters and hot and dry summers. The lambs were monitored monthly for gastrointestinal nematodes using nematode faecal egg counts, from February 2008 to February 2009. Every 2 months, two of the original 30 permanent lambs were necropsied after being held in pens for three weeks so that recently ingested infective larvae could develop into adults. The highest percentage of fourth stage larvae (L4), reaching 48% of the total worm burden, was recorded in abomasal contents in June. Teladorsagia and other Ostertagiinae constituted the highest percentage of L4 larvae (71%), whereas the percentage of Trichostrongylus (17.4%) or Haemonchus (11.6%) remained low. The dynamics of infection observed here (highest faecal egg count in August) and the stage composition of worm burden (highest percentage of L4 in June) provide strong evidence that arrested development had occurred. PMID:27608531

  19. Lipopolysaccharide (LPS introduction during growth and development period of rat’s tooth toward the occurrence of enamel hypoplasia

    Directory of Open Access Journals (Sweden)

    Didin Erma Indahyani

    2007-06-01

    Full Text Available The aim of this study is to know the effect of lipopoly saccharide (LPS induction during growth and development period specifically the occurrence of hypoplasia on tooth enamel. 5 day old male wistar rats divided into two groups. Group 1 (control under went no treatment. Group 2 (treatment under went LPS induction every 24 hour for 8 days on buccal fold right maxillary first molar. After 21 days old the rats were sacrificed and the tooth was resected. Hypoplasia Hypo calcification Index (HHI was used to determine the degree of hypoplasia by clinical examination. Radiograph of maxilla was also taken to analyze the apacities of enamel by using COREL DRAW version 11. The result showed that group under went LPS induction hypoplasia occurred on its molar tooth and more radiolucent than control groups. The conclusion is LPS induction during growth and development period of rats tooth causing enamel hypoplasia.

  20. Cardiac arrest

    Science.gov (United States)

    ... Article.jsp. Accessed June 16, 2014. Myerburg RJ, Castellanos A. Approach to cardiac arrest and life-threatening ... PA: Elsevier Saunders; 2011:chap 63. Myerburg RJ, Castellanos A. Cardiac arrest and audden aardiac death. In: ...

  1. Natural selection and molecular evolution in primate PAX9 gene, a major determinant of tooth development.

    Science.gov (United States)

    Pereira, Tiago V; Salzano, Francisco M; Mostowska, Adrianna; Trzeciak, Wieslaw H; Ruiz-Linares, Andrés; Chies, José A B; Saavedra, Carmen; Nagamachi, Cleusa; Hurtado, Ana M; Hill, Kim; Castro-de-Guerra, Dinorah; Silva-Júnior, Wilson A; Bortolini, Maria-Cátira

    2006-04-11

    Large differences in relation to dental size, number, and morphology among and within modern human populations and between modern humans and other primate species have been observed. Molecular studies have demonstrated that tooth development is under strict genetic control, but, the genetic basis of primate tooth variation remains unknown. The PAX9 gene, which codes for a paired domain-containing transcription factor that plays an essential role in the development of mammal dentition, has been associated with selective tooth agenesis in humans and mice, which mainly involves the posterior teeth. To determine whether this gene is polymorphic in humans, we sequenced approximately 2.1 kb of the entire four-exon region (exons 1, 2, 3 and 4; 1,026 bp) and exon-intron (1.1 kb) boundaries of 86 individuals sampled from Asian, European, and Native American populations. We provided evidence that human PAX9 polymorphisms are limited to exon 3 only and furnished details about the distribution of a mutation there in 350 Polish subjects. To investigate the pattern of selective pressure on exon 3, we sequenced ortholog regions of this exon in four species of New World monkeys and one gorilla. In addition, orthologous sequences of PAX9 available in public databases were also analyzed. Although several differences were identified between humans and other species, our findings support the view that strong purifying selection is acting on PAX9. New World and Old World primate lineages may, however, have different degrees of restriction for changes in this DNA region.

  2. Osteoadherin accumulates in the predentin towards the mineralization front in the developing tooth.

    Directory of Open Access Journals (Sweden)

    Hero Nikdin

    Full Text Available BACKGROUND: Proteoglycans (PG are known to be involved in the organization and assembly of the extracellular matrix (ECM prior to mineral deposition. Osteoadherin (OSAD, a keratan sulphate PG is a member of the small leucine-rich (SLRP family of PGs and unlike other SLRPs, OSAD expression is restricted to mineralized tissues. It is proposed to have a high affinity for hydroxyapatite and has been shown to be expressed by mature osteoblasts but its exact role remains to be elucidated. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the protein distribution of OSAD in the developing mouse tooth using immunohistochemistry and compared its expression with other SLRPs, biglycan (BGN, decorin (DCN and fibromodulin (FMD. OSAD was found to be specifically localized in the predentin layer of the tooth and focused at the mineralization front. These studies were confirmed at the ultrastructural level using electron microscopy (iEM, where the distribution of immunogold labeled OSAD particles were quantified and significant amounts were found in the predentin, forming a gradient towards the mineralization front. In addition, iEM results revealed OSAD to lie in close association with collagen fibers, further suggesting an important role for OSAD in the organization of the ECM. The expression profile of mineralization-related SLRP genes by rat dental pulp cells exposed to mineralization inducing factors, showed an increase in all SLRP genes. Indeed, OSAD expression was significantly increased during the mineralization process, specifically following, matrix maturation, and finally mineral deposition. Alizarin Red S staining for calcium deposition showed clear bone-like nodules, which support matrix maturation and mineralization. CONCLUSIONS: These studies provide new evidence for the role of OSAD in the mineralization process and its specific localization in the predentin layer accumulating at the mineralization front highlighting its role in tooth development.

  3. Functional tooth regenerative therapy: tooth tissue regeneration and whole-tooth replacement.

    Science.gov (United States)

    Oshima, Masamitsu; Tsuji, Takashi

    2014-07-01

    Oral and general health is compromised by irreversible dental problems, including dental caries, periodontal disease and tooth injury. Regenerative therapy for tooth tissue repair and whole-tooth replacement is currently considered a novel therapeutic concept with the potential for the full recovery of tooth function. Several types of stem cells and cell-activating cytokines have been identified in oral tissues. These cells are thought to be candidate cell sources for tooth tissue regenerative therapies because they have the ability to differentiate into tooth tissues in vitro and in vivo. Whole-tooth replacement therapy is regarded as an important model for the development of an organ regenerative concept. A novel three-dimensional cell-manipulation method, designated the organ germ method, has been developed to recapitulate organogenesis. This method involves compartmentalisation of epithelial and mesenchymal cells at a high cell density to mimic multicellular assembly conditions and epithelial-mesenchymal interactions. A bioengineered tooth germ can generate a structurally correct tooth in vitro and erupt successfully with the correct tooth structure when transplanted into the oral cavity. We have ectopically generated a bioengineered tooth unit composed of a mature tooth, periodontal ligament and alveolar bone, and that tooth unit was successfully engrafted into an adult jawbone through bone integration. Such bioengineered teeth were able to perform normal physiological tooth functions, such as developing a masticatory potential in response to mechanical stress and a perceptive potential for noxious stimuli. In this review, we describe recent findings and technologies underpinning tooth regenerative therapy.

  4. Tooth development and histology patterns in lamniform sharks (Elasmobranchii, Lamniformes) revisited.

    Science.gov (United States)

    Schnetz, Lisa; Pfaff, Cathrin; Kriwet, Jürgen

    2016-12-01

    The dentition of lamniforme sharks exhibits several characters that have been used extensively to resolve the phylogenetic relationships of extant taxa, yet some uncertainties remain. Also, the development of different teeth of a tooth file within the jaws of most extant lamniforms has not been documented to date. High-resolution micro-computed tomography is used here to re-evaluate the importance of two dental characters within the order Lamniformes, which were considered not to be phylogenetically informative, the histotype and the number of teeth per tooth file. Additionally, the development and mineralization patterns of the teeth of the two osteodont lamniforms Lamna nasus and Alopias superciliosus were compared. We discuss the importance of these dental characters for phylogenetic interpretations to assess the quality of these characters in resolving lamniform relationships. The dental characters suggest that (1) Lamniformes are the only modern-level sharks exhibiting the osteodont histotype, (2) the osteodont histotype in lamniform sharks is a derived state in modern-level sharks (Elasmobranchii), (3) the osteodont type, conversely is convergently achieved when the clade Chondrichthyes is considered and thus might comprise a functional rather than a phylogenetic signal, and (4) there is an increase in the number of teeth per file throughout lamniform phylogeny. Structural development of the teeth of L. nasus and A. superciliosus is congruent with a previous investigation of the lamniform shark Carcharodon carcharias. J. Morphol. 277:1584-1598, 2016. © 2016 Wiley Periodicals, Inc.

  5. Continuity and Change from Adolescence to Emerging Adulthood: Adolescence-Limited vs. Life-Course-Persistent Profound Ego Development Arrests

    Science.gov (United States)

    Billings, Rebecca L.; Hauser, Stuart T.; Allen, Joseph P.

    2008-01-01

    Participants (n = 36) with consistent Pre-conformist ego development levels during multiple adolescent assessments were studied to determine whether and how their ego levels had changed at age 25. Those (n = 12) whose ego levels remained at the Pre-conformist level were assigned to a "life-course-persistent profound ego development arrest"…

  6. Limb, tooth, beak: Three modes of development and evolutionary innovation of form

    Indian Academy of Sciences (India)

    Marta Linde-Medina; Stuart A Newman

    2014-04-01

    The standard model of evolutionary change of form, deriving from Darwin’s theory via the Modern Synthesis, assumes a gradualistic reshaping of anatomical structures, with major changes only occurring by many cycles of natural selection for marginal adaptive advantage. This model, with its assertion that a single mechanism underlies both micro- and macroevolutionary change, contains an implicit notion of development which is only applicable in some cases. Here we compare the embryological processes that shape the vertebrate limb bud, the mammalian tooth and the avian beak. The implied notion of development in the standard evolutionary picture is met only in the case of the vertebrate limb, a single-primordium organ with morphostatic shaping, in which cells rearrange in response to signalling centres which are essentially unchanged by cell movement. In the case of the tooth, a single-primordium organ with morphodynamic shaping in which the strengths and relationships between signalling centres is influenced by the cell and tissue movements they induce, and the beak, in which the final form is influenced by the collision and rearrangement of multiple tissue primordia, abrupt appearance of qualitatively different forms (i.e. morphological novelties) can occur with small changes in system parameters induced by a genetic change, or by an environmental factor whose effects can be subsequently canalized genetically. Bringing developmental mechanisms and, specifically, the material properties of tissues as excitable media into the evolutionary picture, demonstrates that gradualistic change for incremental adaptive advantage is only one of the possible modes of morphological evolution.

  7. Msx1 expression regulation by its own antisense RNA: consequence on tooth development and bone regeneration.

    Science.gov (United States)

    Babajko, Sylvie; Petit, Stéphane; Fernandes, Isabelle; Méary, Fleur; LeBihan, Johanne; Pibouin, Laurence; Berdal, Ariane

    2009-01-01

    Msx homeogenes play an important role in epithelial-mesenchymal interactions leading development. Msx1 is relevant for dental and craniofacial morphogenesis, as suggested by phenotypes of Msx1 mutations in human and Msx1 KO mice. During adulthood, Msx1 is still expressed in the skeleton where its role is largely unknown. Our group showed that the Msx1 gene is submitted to bidirectional transcription generating a long noncoding antisense (AS) RNA. During tooth development, Msx1 sense (S) and AS RNAs showed specific patterns of expression. Thus, the aim of the present study was to analyze the relation between Msx1 S and AS RNAs. In vivo mapping in adult mice showed that both Msx1 RNAs were detected in tested tissues such as bone. In vitro, Msx1 AS RNA decreased endogenous Msx1 S expression and modified Msx1 protein cell distribution. Regulations of Dlx5 and Bmp4 expression involving Msx1 S and AS RNAs showed that Msx1 AS RNA could modulate Msx1 function. The study of Msx1 S and AS RNA status is interesting in the case of tooth agenesis and bone loss to see if a disturbance of this balance could be associated with a disturbance of bone homeostasis. In that sense, our current results suggest a clear involvement of Msx1 in alveolar bone.

  8. Limb, tooth, beak: three modes of development and evolutionary innovation of form.

    Science.gov (United States)

    Linde-Medina, Marta; Newman, Stuart A

    2014-04-01

    The standard model of evolutionary change of form, deriving from Darwin's theory via the Modern Synthesis, assumes a gradualistic reshaping of anatomical structures, with major changes only occurring by many cycles of natural selection for marginal adaptive advantage. This model, with its assertion that a single mechanism underlies both micro- and macroevolutionary change, contains an implicit notion of development which is only applicable in some cases. Here we compare the embryological processes that shape the vertebrate limb bud, the mammalian tooth and the avian beak. The implied notion of development in the standard evolutionary picture is met only in the case of the vertebrate limb, a single-primordium organ with morphostatic shaping, in which cells rearrange in response to signalling centres which are essentially unchanged by cell movement. In the case of the tooth, a single-primordium organ with morphodynamic shaping in which the strengths and relationships between signalling centres is influenced by the cell and tissue movements they induce, and the beak, in which the final form is influenced by the collision and rearrangement of multiple tissue primordia, abrupt appearance of qualitatively different forms (i.e. morphological novelties) can occur with small changes in system parameters induced by a genetic change, or by an environmental factor whose effects can be subsequently canalized genetically. Bringing developmental mechanisms and, specifically, the material properties of tissues as excitable media into the evolutionary picture, demonstrates that gradualistic change for incremental adaptive advantage is only one of the possible modes of morphological evolution.

  9. New developed cylindrical TM010 mode EPR cavity for X-band in vivo tooth dosimetry.

    Directory of Open Access Journals (Sweden)

    Guo Junwang

    Full Text Available EPR tooth in vivo dosimetry is an attractive approach for initial triage after unexpected nuclear events. An X-band cylindrical TM010 mode resonant cavity was developed for in vivo tooth dosimetry and used in EPR applications for the first time. The cavity had a trapezoidal measuring aperture at the exact position of the cavity's cylindrical wall where strong microwave magnetic field H1 concentrated and weak microwave electric field E1 distributed. Theoretical calculations and simulations were used to design and optimize the cavity parameters. The cavity features were evaluated by measuring DPPH sample, intact incisor samples embed in a gum model and the rhesus monkey teeth. The results showed that the cavity worked at designed frequency and had the ability to make EPR spectroscopy in relative high sensitivity. Sufficient modulation amplitude and microwave power could be applied into the aperture. Radiation induced EPR signal could be observed remarkably from 1 Gy irradiated intact incisor within only 30 seconds, which was among the best in scan time and detection limit. The in vivo spectroscopy was also realized by acquiring the radiation induced EPR signal from teeth of rhesus monkey whose teeth was irradiated by dose of 2 Gy. The results suggested that the cavity was sensitive to meet the demand to assess doses of significant level in short time. This cavity provided a very potential option for the development of X-band in vivo dosimetry.

  10. Development of an Electro–Thermal Model for ZnO Surge Arrester Under Contamination

    Directory of Open Access Journals (Sweden)

    E. Melgoza–Vázquez

    2010-01-01

    Full Text Available An electro–thermal model for a Zinc Oxide (ZnO surge arrester under contamination tests is presented. The model is based in three sub–models: electrical, thermal and contamination, which interact in order to obtain the surge arrester performance under contamination tests. The electrical model is obtained from measurements and is based on a capacitance and a non–linear resistor. The thermal model takes into account the heat generated and dissipated by the column of varistors and its surroundings. The contamination is represented by a dynamic impedance obtained from measurements in the arrester column during contamination tests. The full model is validated by calculating the temperature increase during contamination tests carried out in a two units ZnO surge arrester, class 190 kV. Finally, the results of the effect of several design and construction parameters in the voltage and temperature distribution in the arrester columns during contamination tests are presented.

  11. Development of a Web GIS Application for Visualizing and Analyzing Community Out of Hospital Cardiac Arrest Patterns.

    Science.gov (United States)

    Semple, Hugh; Qin, Han; Sasson, Comilla

    2013-01-01

    Improving survival rates at the neighborhood level is increasingly seen as a priority for reducing overall rates of out-of-hospital cardiac arrest (OHCA) in the United States. Since wide disparities exist in OHCA rates at the neighborhood level, it is important for public health officials and residents to be able to quickly locate neighborhoods where people are at elevated risk for cardiac arrest and to target these areas for educational outreach and other mitigation strategies. This paper describes an OHCA web mapping application that was developed to provide users with interactive maps and data for them to quickly visualize and analyze the geographic pattern of cardiac arrest rates, bystander CPR rates, and survival rates at the neighborhood level in different U.S. cities. The data comes from the CARES Registry and is provided over a period spanning several years so users can visualize trends in neighborhood out-of-hospital cardiac arrest patterns. Users can also visualize areas that are statistical hot and cold spots for cardiac arrest and compare OHCA and bystander CPR rates in the hot and cold spots. Although not designed as a public participation GIS (PPGIS), this application seeks to provide a forum around which data and maps about local patterns of OHCA can be shared, analyzed and discussed with a view of empowering local communities to take action to address the high rates of OHCA in their vicinity.

  12. Decoronation for the management of an ankylosed young permanent tooth.

    Science.gov (United States)

    Sapir, Shabtai; Shapira, Joseph

    2008-02-01

    Replacement resorption rate is a variable process, and is dependent on age, basal metabolic rate, extra-alveolar time, treatment prior to replantation, amount of root dentin, severity of trauma, and extent of periodontal ligament necrosis. In patients 7-16 years old a tooth is lost 3-7 years after the onset of root resorption. The complications that may develop as a consequence of ankylosis of a permanent incisor in children are due to the inevitable early loss of the traumatized tooth and local arrest of alveolar bone development. An ankylosed tooth should be removed before the changes become so pronounced that they compromise future prosthetic treatment. The treatment options may involve: interceptive regenerative treatment, early extraction of the ankylosed tooth, orthodontic space closure, intentional replantation, extraction of the ankylosed tooth followed with immediate ridge augmentation/preservation, auto-transplantation, single tooth dento-osseous osteotomy, and decoronation. The purpose of this article was to review the considerations involved in the decision-making concerning the use of the decoronation technique for the treatment of a permanent incisor diagnosed as ankylosed.

  13. Defining properties of neural crest-derived progenitor cells from the apex of human developing tooth.

    Science.gov (United States)

    Degistirici, Ozer; Jaquiery, Claude; Schönebeck, Bodo; Siemonsmeier, Jürgen; Götz, Werner; Martin, Ivan; Thie, Michael

    2008-02-01

    The connective tissue of the human tooth arises from cells that are derived from the cranial neural crest and, thus, are termed as "ectomesenchymal cells." Here, cells being located in a pad-like tissue adjacent to the apex of the developing tooth, which we designated the third molar pad, were separated by the microexplant technique. When outgrowing from the explant, dental neural crest-derived progenitor cells (dNC-PCs) adhered to plastic, proliferated steadily, and displayed a fibroblast-like morphology. At the mRNA level, dNC-PCs expressed neural crest marker genes like Sox9, Snail1, Snail2, Twist1, Msx2, and Dlx6. Cytofluorometric analysis indicated that cells were positive for CD49d (alpha4 integrin), CD56 (NCAM), and PDGFRalpha, while negative for CD31, CD34, CD45, and STRO-1. dNC-PCs could be differentiated into neurogenic, chondrogenic, and osteogenic lineages and were shown to produce bone matrix in athymic mice. These results demonstrate that human third molar pad possesses neural crest-derived cells that represent multipotent stem/progenitor cells. As a rather large amount of dNC-PCs could be obtained from each single third molar, cells may be used to regenerate a wide range of tissues within the craniofacial region of humans.

  14. Shark tooth morphogenesis. An SEM and EDX analysis of enameloid and dentin development in various shark species.

    Science.gov (United States)

    Risnes, S

    1990-09-01

    The study provides a survey of shark tooth morphogenesis based on SEM and EDX analyses of whole tooth families in six shark species. The teeth, demonstrating different stages of development, were acid-etched and coated with palladium. Calcium content was determined semi-quantitatively by using the palladium coating as an internal standard. Due to the rapid development of the enameloid, all major events took place in the two or three youngest teeth of a tooth family. Enameloid appeared to develop as a transformation of the peripheral part of the dental papilla. Mineralization started immediately. Based on morphological criteria the middle zone of the enameloid was established at an early stage, excluding the possibility of an unambiguous centrifugal or centripetal direction of growth. Substantial mineral increase first occurred in the middle zone, spreading from the tooth tip toward the base. Dentin formed after the enameloid was completely established. Dentin formation started basally as a direct prolongation of the enameloid cap, then spreading toward the tooth tip, first along the edges. It is concluded that shark enameloid has a mesenchymal background, but a role played by the inner dental epithelium can not be excluded.

  15. Tooth anatomy

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/002214.htm Tooth anatomy To use the sharing features on this page, ... upper jawbone is called the maxilla. Images Tooth anatomy References Lingen MW. Head and neck. In: Kumar ...

  16. Signi fi cance of Neural Crest in Tooth Development: The Molecular Signature

    Directory of Open Access Journals (Sweden)

    VP Jayasekharan

    2014-07-01

    Full Text Available The neural crest originates from cells located along the lateral margins of the neural plate. Neural crest cells arise as the result of an inductive action by the non-neural ectoderm adjacent to the neural plate and possibly by nearby mesoderm as well. As the neural tube forms, a group of cells separate from the neuro- ectoderm. These cells have the capacity to migrate and differen- tiate extensively within the developing embryo and they are the basis of structures such as spinal sensory ganglia, sympathetic neurons, Schwann cells, pigment cells and meninges. Speci fi c interactions occur during the development of tooth and recent research has concentrated more on the molecular aspects of these interactions. Thus, it is highly imperative to understand and digress the complex mechanisms involved in these processes

  17. Sorbitol as an arrester of embryonic development in diapausing eggs of the silkworm, Bombyx mori.

    Science.gov (United States)

    Horie; Kanda; Mochida

    2000-06-01

    Recently, it was confirmed that embryos derived from diapausing eggs of the silkworm, Bombyx mori, begin their development and reach larval maturity on mulberry leaves, when the naked eggs are cultured in vitro. In this study, we found that the method of embryo culture is useful for determining the physiological regulation of diapause. We show that the development of embryos derived from diapausing eggs was strongly inhibited by the addition of either sorbitol or trehalose to the culture medium. Furthermore, this inhibitory effect disappeared when the embryos were cultured in a control medium which did not contain either sorbitol or trehalose, indicating that the inhibitory reactions caused by both substances are reversible. The minimal effective dose of either sorbitol or trehalose was approximately 0.2 M, a value similar to the in vivo concentration of sorbitol in diapausing eggs (0.2 M). Glycerol, mannitol or glucose were moderately effective for inhibition. Sorbitol present in diapausing silkworm eggs does not appear to serve as an antifreeze, but as an strong arresting factor of embryonic development. Furthermore, these results show that a decrease in sorbitol releases the embryos from diapause at the termination of diapause.

  18. Quantitative analysis of fluoride-induced hypermineralization of developing enamel in neonatal hamster tooth germs

    Science.gov (United States)

    Tros, G. H. J.; Lyaruu, D. M.; Vis, R. D.

    1993-10-01

    A procedure was developed for analysing the effect of fluoride on mineralization in the enamel of neonatal hamster molars during amelogenesis by means of the quantitative determination of the mineral content. In this procedure the distribution of calcium and mineral concentration was determined in sections containing developing tooth enamel mineral embedded in an organic epoxy resin matrix by means of the micro-PIXE technique. This allowed the determination of the calcium content along preselected tracks with a spatial resolution of 2 μm using a microprobe PIXE setup with a 3 MeV proton beam of 10 to 50 pA with a spot size of 2 μm in the track direction. In this procedure the X-ray yield is used as a measure for the calcium content. The thickness of each sample section is determined independently by measuring the energy loss of α-particles from a calibration source upon passing through the sample. The sample is considered as consisting of two bulk materials, allowing the correction for X-ray self-absorption and the calculation of the calcium concentration. The procedure was applied for measuring the distribution of mineral concentration in 2 μm thick sections taken from tooth germs of hamsters administered with NaF. The measurements indicated that a single intraperitoneal administration of 20 mg NaF/kg body weight to 4-to-5-day-old hamsters leads within 24 h to hypermineralization of certain focal enamel surface areas containing cystic lesions under transitional and early secretory ameloblasts. The mineral concentration there is substantially increased due to the fluoride treatment (35%, instead of 5 to 10% as in the controls), indicating that the normal mineralization process has been seriously disturbed. Furthermore it is found that using this technique the mineral concentration peaks at about 70% at the dentine-enamel junction, which is comparable to that reported for human dentine using other techniques.

  19. Esthetic and endosurgical management of turner′s hypoplasia; a sequlae of trauma to developing tooth germ

    Directory of Open Access Journals (Sweden)

    Bhushan B

    2008-12-01

    Full Text Available Turner′s hypoplasia usually manifests as a portion of missing or diminished enamel, generally affecting one or more permanent teeth in the oral cavity. A case report of 8 year old girl who met with trauma at 2 years of age leading to primary incisors being knocked out, reported after 6 years with complaint of pain and discharge in her anterior malformed teeth is discussed in this article. The permanent incisors erupted with dilacerated crown, root malformations and missing enamel. Further, patient developed sinus, lateral root pathology, tooth mobility and malocclusion in relation to affected teeth which were managed by esthetic, functional, endodontic and surgical procedure. Root canal treatment along with palatal contouring and esthetic restoration by light cure composite was performed on the tooth with crown dilaceration and sinus, where as surgical management was considered for the tooth with root malformation.

  20. Bone morphogenetic protein-2 gene controls tooth root development in coordination with formation of the periodontium

    Institute of Scientific and Technical Information of China (English)

    Audrey Rakian; Wu-Chen Yang; Jelica Gluhak-Heinrich; Yong Cui; Marie A Harris; Demitri Villarreal; Jerry Q Feng; Mary MacDougall; Stephen E Harris

    2013-01-01

    Formation of the periodontium begins following onset of tooth-root formation in a coordinated manner after birth. Dental follicle progenitor cells are thought to form the cementum, alveolar bone and Sharpey’s fibers of the periodontal ligament (PDL). However, little is known about the regulatory morphogens that control differentiation and function of these progenitor cells, as well as the progenitor cells involved in crown and root formation. We investigated the role of bone morphogenetic protein-2 (Bmp2) in these processes by the conditional removal of the Bmp2 gene using the Sp7-Cre-EGFP mouse model. Sp7-Cre-EGFP first becomes active at E18 in the first molar, with robust Cre activity at postnatal day 0 (P0), followed by Cre activity in the second molar, which occurs after P0. There is robust Cre activity in the periodontium and third molars by 2 weeks of age. When the Bmp2 gene is removed from Sp71 (Osterix1) cells, major defects are noted in root, cellular cementum and periodontium formation. First, there are major cell autonomous defects in root-odontoblast terminal differentiation. Second, there are major alterations in formation of the PDLs and cellular cementum, correlated with decreased nuclear factor IC (Nfic), periostin and a-SMA1 cells. Third, there is a failure to produce vascular endothelial growth factor A (VEGF-A) in the periodontium and the pulp leading to decreased formation of the microvascular and associated candidate stem cells in the Bmp2-cKOSp7-Cre-EGFP. Fourth, ameloblast function and enamel formation are indirectly altered in the Bmp2-cKOSp7-Cre-EGFP. These data demonstrate that the Bmp2 gene has complex roles in postnatal tooth development and periodontium formation.

  1. Daily Arrests

    Data.gov (United States)

    Montgomery County of Maryland — This dataset provides the public with arrest information from the Montgomery County Central Processing Unit (CPU) systems. The data presented is derived from every...

  2. Human dental age estimation combining third molar(s) development and tooth morphological age predictors.

    Science.gov (United States)

    Thevissen, P W; Galiti, D; Willems, G

    2012-11-01

    In the subadult age group, third molar development, as well as age-related morphological tooth information can be observed on panoramic radiographs. The aim of present study was to combine, in subadults, panoramic radiographic data based on developmental stages of third molar(s) and morphological measurements from permanent teeth, in order to evaluate its added age-predicting performances. In the age range between 15 and 23 years, 25 gender-specific radiographs were collected within each age category of 1 year. Third molar development was classified and registered according the 10-point staging and scoring technique proposed by Gleiser and Hunt (1955), modified by Köhler (1994). The Kvaal (1995) measuring technique was applied on the indicated teeth from the individuals' left side. Linear regression models with age as response and third molar-scored stages as explanatory variables were developed, and morphological measurements from permanent teeth were added. From the models, determination coefficients (R (2)) and root-mean-square errors (RMSE) were calculated. Maximal-added age information was reported as a 6 % R² increase and a 0.10-year decrease of RMSE. Forensic dental age estimations on panoramic radiographic data in the subadult group (15-23 year) should only be based on third molar development.

  3. Intra-epithelial requirement of canonical Wnt signaling for tooth morphogenesis.

    Science.gov (United States)

    Zhu, XiaoJing; Zhao, Pan; Liu, YuDong; Zhang, XiaoYun; Fu, Jiang; Ivy Yu, H-M; Qiu, Mengsheng; Chen, YiPing; Hsu, Wei; Zhang, Zunyi

    2013-04-26

    Multiple Wnt ligands are expressed in the developing tooth and play important and redundant functions during odontogenesis. However, the source of Wnt ligands and their targeting cells and action mechanism in tooth organogenesis remain largely elusive. Here we show that epithelial inactivation of Gpr177, the mouse Wntless (Wls) whose product regulates Wnt sorting and secretion, leads to arrest of tooth development at the early cap stage and abrogates tooth-forming capability of the dental epithelium. Gpr177 in the epithelium is necessary for the activation of canonical Wnt signaling in the dental epithelium and formation of a functional enamel knot. Epithelial deletion of Gpr177 results in defective gene expression and cellular behavior in the dental epithelium but does not alter odontogenic program in the mesenchyme. Furthermore, deletion of Axin2, a negative intracellular regulator of canonical Wnt signaling, rescues the tooth defects in mice carrying Gpr177 mutation in the dental epithelium. Together with the fact that active Wnt canonical signaling is present predominantly in the dental epithelium during tooth development, our results demonstrate that Gpr177-mediated Wnt ligands in the dental epithelium act primarily in an intra-epithelial context to regulate enamel knot formation and subsequent tooth development.

  4. Age estimation in Portuguese population: The application of the London atlas of tooth development and eruption.

    Science.gov (United States)

    Pavlović, Strahinja; Palmela Pereira, Cristiana; Vargas de Sousa Santos, Rui Filipe

    2017-03-01

    Chronological age estimation from the dental parameters is becoming increasingly important. The London atlas of tooth development is the most recent developed method and represents a modification of the previous older methods. The aim of this study was to evaluate the accuracy of the London atlas for the dental age estimation in the Portuguese population. The study sample included 736 radiographic images (498 females and 238 males) of Portuguese origin, patients of Dental Clinic of Superior Institute of Health Sciences Egas Moniz and Dental Medicine Faculty, University of Lisbon. The age range of the individuals was between 3 and 24 years. Estimated age was compared with the chronological age using the paired t-test. The results showed that there was no statistically significant difference between left and right side of the jaw (p>0.05). Both sides showed an average overestimation of age by one month approximately. Moreover, the significant difference between chronological and estimated age was not observed in the females. However, the significant difference was observed in a sample coming from males (right: p=0.008; left: p=0.003). Our results showed that the London atlas can be potentially used as a tool for age estimation. However, the difference between sexes clearly suggests that separate charts should be made for each sex. Further studies, which will have as a final goal the development of a new method for age estimation using dental parameters, are needed.

  5. Over-expression of thymosin beta 4 promotes abnormal tooth development and stimulation of hair growth.

    Science.gov (United States)

    Cha, Hee-Jae; Philp, Deborah; Lee, Soo-Hyun; Moon, Hye-Sung; Kleinman, Hynda K; Nakamura, Takashi

    2010-01-01

    Thymosin beta 4 has multi-functional roles in cell physiology. It accelerates wound healing, hair growth and angiogenesis, and increases laminin-5 expression in corneal epithelium. Furthermore, thymosin beta 4 stimulates tumor growth and metastasis by induction of cell migration and vascular endothelial growth factor-mediated angiogenesis. Using a construct on the skin-specific keratin-5 promoter, we have developed thymosin beta 4 over-expressing transgenic mice to further study its functional roles. Thymosin beta 4 in adult skin and in embryonic stages of the transgenic mouse was analyzed by both Western blot and immunohistochemistry. The over-expression of thymosin beta 4 was observed especially around hair follicles and in the teeth in the transgenic mice. We examined the phenotype of the thymosin beta 4 over-expressing mice. Hair growth was accelerated. In addition, the transgenic mice had abnormally-shaped white teeth and dull incisors. We found that the expression of laminin-5 was up-regulated in the skin of the transgenic mice. We conclude that thymosin beta 4 has an important physiological role in hair growth and in tooth development.

  6. Lhx8 mediated Wnt and TGFβ pathways in tooth development and regeneration.

    Science.gov (United States)

    Zhou, Chen; Yang, Guodong; Chen, Mo; Wang, Chenglin; He, Ling; Xiang, Lusai; Chen, Danying; Ling, Junqi; Mao, Jeremy J

    2015-09-01

    LIM homeobox 8 (Lhx8) is a highly conserved transcriptional factor with recently illustrated roles in cholinergic and GABAergic differentiation, and is expressed in neural crest derived craniofacial tissues during development. However, Lhx8 functions and signaling pathways are largely elusive. Here we showed that Lhx8 regulates dental mesenchyme differentiation and function via Wnt and TGFβ pathways. Lhx8 expression was restricted to dental mesenchyme from E11.5 to a peak at E14.5, and absent in dental epithelium. By reconstituting dental epithelium and mesenchyme in an E16.5 tooth organ, Lhx8 knockdown accelerated dental mesenchyme differentiation; conversely, Lhx8 overexpression attenuated dentin formation. Lhx8 overexpressed adult human dental pulp stem/progenitor cells in β-tricalcium phosphate cubes attenuated mineralized matrix production in vivo. Gene profiling revealed that postnatal dental pulp stem/progenitor cells upon Lhx8 overexpression modified matrix related gene expression including Dspp, Cola1 and osteocalcin. Lhx8 transcriptionally activated Wnt and TGFβ pathways, and its attenuation upregulated multiple dentinogenesis genes. Together, Lhx8 regulates dentin development and regeneration by fine-turning Wnt and TGFβ signaling.

  7. Development of expert system software to improve performance of high-voltage arresters in substations

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Andre Nunes de; Oltremari, Anderson; Zago, Maria Goretti; Silva, Paulo Sergio da; Costa Junior, Pedro da; Ferraz, Kleber [Sao Paulo State Univ. (UNESP), Bauru, SP (Brazil). Lab. of Power Systems and Intelligent Techniques], E-mail: andrejau@feb.unesp.br; Gusmao, Euripedes Silva; Prado, Jose Martins [ELETRONORTE, MT (Brazil)], E-mail: euripedes.gusmao@eln.gov.br

    2007-07-01

    One of the main causes of interruption and power outage on the energy distribution system in Brazil is related to lightning, which is also the main responsible by the reduction of service life and destruction of consumers and Utilities' equipment. As a manner of improving the protection of the energy distribution system, the Utilities have given attention on establishing maintenance techniques, such preventive as predictive, of the high-voltage arresters in substation. Currently, one of the main manners to obtain the installed arresters' characteristics involves the utilization of high cost equipment, such as leakage current meters. In this way, this paper aims to fulfill the needs of obtaining reliable results with the utilization of lower cost equipment, proposing a Expert System Software for diagnosing and aiding to decision through the utilization of intelligent techniques, which makes possible the monitoring of service life and the identification of aged arresters, allowing the establishment of one reliable chronogram for the removal of equipment, such for maintenance as for substitution. (author)

  8. Arrested diatreme development: Standing Rocks East, Hopi Buttes, Navajo Nation, USA

    Science.gov (United States)

    Lefebvre, Nathalie S.; White, James D. L.; Kjarsgaard, Bruce A.

    2016-01-01

    fluidal, folded-over shapes and ropy surfaces, subordinate thermally altered wall-rock and variegated domains of lapilli tuff. SRE shows a progressive transition from fissure to diatreme, and overall evolution from more explosive to weakly explosive eruption styles recorded at the conduit-crater transition. Diatreme development was initiated by deep-quarrying explosive eruptions along a fissure to form the country rock-rich breccia. Only parts of the fissure remained active as magma feeding the highly explosive eruptions along the fissure localized into discrete point sources forming the matrix-rich lapilli tuff deposits. These superimposed deposits record the passage of multiple debris-jets and subvertical fallback from shallow cratering arising from explosions triggered by magma-water interaction at numerous, discrete sites. However, instead of continuing to build a well-formed diatreme, the system switched to weak spattering with intermittent explosive activity and near-surface dike emplacement into the unconsolidated anisotropic, pyroclastic debris of the crater floor. Dominant spatter from strombolian-style bursts accumulated on the topographically varied, evolving unstable syn-eruptive crater floor, and led to local failure and remobilization. This study demonstrates how the combination of fissure behavior and sensitivity of the shallow plumbing system to local conditions during an eruption can lead to a decrease in eruptive footprint within the diatreme structure, and an overall decrease in explosivity resulting in the arrested development of an immature diatreme.

  9. Effect of potential role of p53 on embryo development arrest induced by H2O2 in mouse.

    Science.gov (United States)

    Hu, De-Bao; Li, Zhong-Shu; Ali, Ihsan; Xu, Li-Jie; Fang, Nan-Zhu

    2017-01-27

    During mammalian embryo development in vitro, mechanism of embryonic development arrest caused by oxidative stress has not been clear so far. The tumor suppressor protein p53 controls cell cycle and programmed cell death by regulating relevant signal pathway. Recent researches revealed that the concentration and distribution of p53 are closely related with reactive oxygen species (ROS). The main objective of this experiment was to explore the role of p53 on embryonic development arrest caused by oxidative stress. Results showed that embryo arrest at two-four-cell stage was significantly increased in the presence of 50 μM H2O2 (39.01 ± 2.74 vs. 77.20 ± 5.34%, p p53 and p53-ser15. Further increased transcription of GADD45a and p21, a downstream of p53, has an especially significant effect on the mRNA expression of GADD45a. However, expressions of cdc2 were reduced by H2O2. In addition, using Pifithrin-α (PFT-α), the suppresser of p53, the result showed that GADD45a and p21 were significantly downregulated, but the cell cycle gene cdc2 was significantly upregulated, while the protein level of p53 and p53-ser15 was significantly decreased. Taken together, these results demonstrate that ROS could activate p53 and regulate p53 target genes to influence early embryo development in in vitro culture.

  10. Stem cell property of postmigratory cranial neural crest cells and their utility in alveolar bone regeneration and tooth development.

    Science.gov (United States)

    Chung, Il-Hyuk; Yamaza, Takayoshi; Zhao, Hu; Choung, Pill-Hoon; Shi, Songtao; Chai, Yang

    2009-04-01

    The vertebrate neural crest is a multipotent cell population that gives rise to a variety of different cell types. We have discovered that postmigratory cranial neural crest cells (CNCCs) maintain mesenchymal stem cell characteristics and show potential utility for the regeneration of craniofacial structures. We are able to induce the osteogenic differentiation of postmigratory CNCCs, and this differentiation is regulated by bone morphogenetic protein (BMP) and transforming growth factor-beta signaling pathways. After transplantation into a host animal, postmigratory CNCCs form bone matrix. CNCC-formed bones are distinct from bones regenerated by bone marrow mesenchymal stem cells. In addition, CNCCs support tooth germ survival via BMP signaling in our CNCC-tooth germ cotransplantation system. Thus, we conclude that postmigratory CNCCs preserve stem cell features, contribute to craniofacial bone formation, and play a fundamental role in supporting tooth organ development. These findings reveal a novel function for postmigratory CNCCs in organ development, and demonstrate the utility of these CNCCs in regenerating craniofacial structures.

  11. Charcot-Marie-Tooth disease: The development of a diagnostic platform using next generation sequencing

    DEFF Research Database (Denmark)

    Christensen, Rikke; Væth, Signe; Thorsen, Kasper;

    Background: Charcot-Marie-Tooth Disease (CMT) is one of the most common inherited neurological diseases. Today, more than 70 CMT related genes are known to cause inherited neuropathy. The diagnostic strategy in most laboratories is based on Sanger-sequencing of few genes. In our patient cohort...

  12. Arrested development - a comparative analysis of multilayer corona textures in high-grade metamorphic rocks

    Science.gov (United States)

    Ogilvie, Paula; Gibson, Roger L.

    2017-02-01

    Coronas, including symplectites, provide vital clues to the presence of arrested reaction and preservation of partial equilibrium in metamorphic and igneous rocks. Compositional zonation across such coronas is common, indicating the persistence of chemical potential gradients and incomplete equilibration. Major controls on corona mineralogy include prevailing pressure (P), temperature (T) and water activity (aH2O) during formation, reaction duration (t) single-stage or sequential corona layer growth; reactant bulk compositions (X) and the extent of metasomatic exchange with the surrounding rock; relative diffusion rates for major components; and/or contemporaneous deformation and strain. High-variance local equilibria in a corona and disequilibrium across the corona as a whole preclude the application of conventional thermobarometry when determining P-T conditions of corona formation, and zonation in phase composition across a corona should not be interpreted as a record of discrete P-T conditions during successive layer growth along the P-T path. Rather, the local equilibria between mineral pairs in corona layers more likely reflect compositional partitioning of the corona domain during steady-state growth at constant P and T. Corona formation in pelitic and mafic rocks requires relatively dry, residual bulk rock compositions. Since most melt is lost along the high-T prograde to peak segment of the P-T path, only a small fraction of melt is generally retained in the residual post-peak assemblage. Reduced melt volumes with cooling limit length scales of diffusion to the extent that diffusion-controlled corona growth occurs. On the prograde path, the low melt (or melt-absent) volumes required for diffusion-controlled corona growth are only commonly realized in mafic igneous rocks, owing to their intrinsic anhydrous bulk composition, and in dry, residual pelitic compositions that have lost melt in an earlier metamorphic event. Experimental work characterizing rate

  13. Simultaneous occurrence of compound odontoma and arrested root formation as developmental disturbances after maxillofacial trauma: a case report.

    Science.gov (United States)

    Güngörmüş, Metin; Yolcu, Umit; Aras, Mutan-Hamdi; Halicioğlu, Koray

    2010-03-01

    Traumatic injury to a primary tooth and/or a bone fracture has the potential to damage the underlying permanent tooth germ which may disturb its development. The extent of the malformation depends on the developmental stage of the permanent tooth and the intensity of the trauma. The presence of infection may be a predictive factor for these abnormalities. Open surgical procedures can also potentially cause impaction and developmental disturbances. Several developmental alterations such as discolouration, hypoplasia, crown dilaceration, root angulation or dilaceration, sequestration of permanent tooth buds and disturbance in eruption have been reported in permanent teeth after trauma. However, odontoma-like malformations and partial or complete arrest of root formation are rare complications developed after trauma. This article presents a rare case with simultaneous occurrence of an odontoma-like malformation and complete and partial arrested root formations as the results of maxillofacial trauma. Almost all pediatric fractures must be managed with closed reduction as much as possible. However, if it is necessary to perform an open reduction, careful attention must be paid during placement of the osteosynthetic plates and screws; and tooth bud development must be followed periodically.

  14. Third molar development: evaluation of nine tooth development registration techniques for age estimations.

    Science.gov (United States)

    Thevissen, Patrick W; Fieuws, Steffen; Willems, Guy

    2013-03-01

    Multiple third molar development registration techniques exist. Therefore the aim of this study was to detect which third molar development registration technique was most promising to use as a tool for subadult age estimation. On a collection of 1199 panoramic radiographs the development of all present third molars was registered following nine different registration techniques [Gleiser, Hunt (GH); Haavikko (HV); Demirjian (DM); Raungpaka (RA); Gustafson, Koch (GK); Harris, Nortje (HN); Kullman (KU); Moorrees (MO); Cameriere (CA)]. Regression models with age as response and the third molar registration as predictor were developed for each registration technique separately. The MO technique disclosed highest R(2) (F 51%, M 45%) and lowest root mean squared error (F 3.42 years; M 3.67 years) values, but differences with other techniques were small in magnitude. The amount of stages utilized in the explored staging techniques slightly influenced the age predictions.

  15. How to develop a clinic for sudden cardiac arrest survivors and families of non-survivors.

    Science.gov (United States)

    Abrams, Dominic J

    2017-01-01

    The investigation of the aetiology of sudden cardiac arrest or death in a young person combines features of a traditional clinical medical examination with those of forensic medicine. Nuances of the immediate peri-event history, when available, can be paramount. New genetic tools have greatly improved the yield of such investigations, but they must be carefully interpreted by genetic specialists. The approach to surviving patients, their family members, and to family members of non-survivors is best achieved in a structured programme that includes all appropriate specialists and support personnel. As an example, this may include all appropriate paediatric and internal medicine specialists, a geneticist, a genetic counsellor, a clinical psychologist, nurse specialist(s), and a programme coordinator. This family-centred strategy affords the patient, if surviving, and all family members the necessary emotional and medical support while at the same time providing the necessary diagnostic and therapeutic approaches.

  16. Dietary restriction and fasting arrest B and T cell development and increase mature B and T cell numbers in bone marrow.

    Science.gov (United States)

    Shushimita, Shushimita; de Bruijn, Marjolein J W; de Bruin, Ron W F; IJzermans, Jan N M; Hendriks, Rudi W; Dor, Frank J M F

    2014-01-01

    Dietary restriction (DR) delays ageing and extends life span. Both long- and short-term DR, as well as short-term fasting provide robust protection against many "neuronal and surgery related damaging phenomena" such as Parkinson's disease and ischemia-reperfusion injury. The exact mechanism behind this phenomenon has not yet been elucidated. Its anti-inflammatory actions prompted us to thoroughly investigate the consequences of DR and fasting on B and T cell compartments in primary and secondary lymphoid organs of male C57Bl/6 mice. In BM we found that DR and fasting cause a decrease in the total B cell population and arrest early B cell development, while increasing the number of recirculating mature B cells. In the fasting group, a significant reduction in peripheral B cell counts was observed in both spleen and mesenteric lymph nodes (mLN). Thymopoiesis was arrested significantly at double negative DN2 stage due to fasting, whereas DR resulted in a partial arrest of thymocyte development at the DN4 stage. Mature CD3(+) T cell populations were increased in BM and decreased in both spleen and mLN. Thus, DR arrests B cell development in the BM but increases the number of recirculating mature B cells. DR also arrests maturation of T cells in thymus, resulting in depletion of mature T cells from spleen and mLN while recruiting them to the BM. The functional relevance in relation to protection against organ damage needs to be determined.

  17. Dietary restriction and fasting arrest B and T cell development and increase mature B and T cell numbers in bone marrow.

    Directory of Open Access Journals (Sweden)

    Shushimita Shushimita

    Full Text Available Dietary restriction (DR delays ageing and extends life span. Both long- and short-term DR, as well as short-term fasting provide robust protection against many "neuronal and surgery related damaging phenomena" such as Parkinson's disease and ischemia-reperfusion injury. The exact mechanism behind this phenomenon has not yet been elucidated. Its anti-inflammatory actions prompted us to thoroughly investigate the consequences of DR and fasting on B and T cell compartments in primary and secondary lymphoid organs of male C57Bl/6 mice. In BM we found that DR and fasting cause a decrease in the total B cell population and arrest early B cell development, while increasing the number of recirculating mature B cells. In the fasting group, a significant reduction in peripheral B cell counts was observed in both spleen and mesenteric lymph nodes (mLN. Thymopoiesis was arrested significantly at double negative DN2 stage due to fasting, whereas DR resulted in a partial arrest of thymocyte development at the DN4 stage. Mature CD3(+ T cell populations were increased in BM and decreased in both spleen and mLN. Thus, DR arrests B cell development in the BM but increases the number of recirculating mature B cells. DR also arrests maturation of T cells in thymus, resulting in depletion of mature T cells from spleen and mLN while recruiting them to the BM. The functional relevance in relation to protection against organ damage needs to be determined.

  18. Smad4-Shh-Nfic signaling cascade-mediated epithelial-mesenchymal interaction is crucial in regulating tooth root development.

    Science.gov (United States)

    Huang, Xiaofeng; Xu, Xun; Bringas, Pablo; Hung, Yee Ping; Chai, Yang

    2010-05-01

    Transforming growth factor beta (TGF-beta)/bone morphogenetic protein (BMP) signaling is crucial for regulating epithelial-mesenchymal interaction during organogenesis, and the canonical Smad pathway-mediated TGF-beta/BMP signaling plays important roles during development and disease. During tooth development, dental epithelial cells, known as Hertwig's epithelial root sheath (HERS), participate in root formation following crown development. However, the functional significance of HERS in regulating root development remains unknown. In this study we investigated the signaling mechanism of Smad4, the common Smad for TGF-beta/BMP signaling, in HERS in regulating root development. Tissue-specific inactivation of Smad4 in HERS results in abnormal enamel and dentin formation in K14-Cre;Smad4(fl/fl) mice. HERS enlarges but cannot elongate to guide root development without Smad4. At the molecular level, Smad4-mediated TGF-beta/BMP signaling is required for Shh expression in HERS and Nfic (nuclear factor Ic) expression in the cranial neural crest (CNC)-derived dental mesenchyme. Nfic is crucial for root development, and loss of Nfic results in a CNC-derived dentin defect similar to the one of K14-Cre;Smad4(fl/fl) mice. Significantly, we show that ectopic Shh induces Nfic expression in dental mesenchyme and partially rescues root development in K14-Cre;Smad4(fl/fl) mice. Taken together, our study has revealed an important signaling mechanism in which TGF-beta/BMP signaling relies on a Smad-dependent mechanism in regulating Nfic expression via Shh signaling to control root development. The interaction between HERS and the CNC-derived dental mesenchyme may guide the size, shape, and number of tooth roots.

  19. Development and microstructure of tooth histotypes in the blue shark, Prionace glauca (Carcharhiniformes: Carcharhinidae) and the great white shark, Carcharodon carcharias (Lamniformes: Lamnidae).

    Science.gov (United States)

    Moyer, Joshua K; Riccio, Mark L; Bemis, William E

    2015-07-01

    Elasmobranchs exhibit two distinct arrangements of mineralized tissues in the teeth that are known as orthodont and osteodont histotypes. Traditionally, it has been said that orthodont teeth maintain a pulp cavity throughout tooth development whereas osteodont teeth are filled with osteodentine and lack a pulp cavity when fully developed. We used light microscopy, scanning electron microscopy, and high-resolution micro-computed tomography to compare the structure and development of elasmobranch teeth representing the two histotypes. As an example of the orthodont histotype, we studied teeth of the blue shark, Prionace glauca (Carcharhiniformes: Carcharhinidae). For the osteodont histotype, we studied teeth of the great white shark, Carcharodon carcharias (Lamniformes: Lamnidae). We document similarities and differences in tooth development and the microstructure of tissues in these two species and review the history of definitions and interpretations of elasmobranch tooth histotypes. We discuss a possible correlation between tooth histotype and tooth replacement and review the history of histotype differentiation in sharks. We find that contrary to a long held misconception, there is no orthodentine in the osteodont teeth of C. carcharias.

  20. Biology of tooth replacement in amniotes

    Institute of Scientific and Technical Information of China (English)

    John A Whitlock; Joy M Richman

    2013-01-01

    Tooth replacement is a common trait to most vertebrates, including mammals. Mammals, however, have lost the capacity for continuous tooth renewal seen in most other vertebrates, and typically have only 1–2 generations of teeth. Here, we review the mechanisms of tooth replacement in reptiles and mammals, and discuss in detail the current and historical theories on control of timing and pattern of tooth replacement and development.

  1. Meiotic arrest in vitro by phosphodiesterase 3-inhibitor enhances maturation capacity of human oocytes and allows subsequent embryonic development.

    Science.gov (United States)

    Nogueira, D; Ron-El, R; Friedler, S; Schachter, M; Raziel, A; Cortvrindt, R; Smitz, J

    2006-01-01

    Controlling nuclear maturation during oocyte culture might improve nuclear-cytoplasmic maturation synchrony. We aimed to evaluate the quality of in vitro-matured, germinal vesicle (GV)-stage human oocytes following a prematuration culture (PMC) with a meiotic arrester, phosphodiesterase 3-inhibitor (PDE3-I). Follicles (diameter, 6-12 mm) were retrieved 34-36 h post-hCG administration from informed, consenting patients who had undergone controlled ovarian stimulation. Cumulus-enclosed oocytes (CEOs) presenting moderate expansion or full compaction were placed in PMC with the PDE3-I, Org9935, for 24 or 48 h. Subsequently, oocytes were removed from PMC, denuded of cumulus cells, matured in vitro, and fertilized, and the resulting embryos were cultured. In the presence of PDE3-I, approximately 98% of the oocytes were arrested at the GV stage. Following PDE3-I removal, oocytes acquired a higher maturation rate than oocytes that were immediately denuded of cumulus cells after retrieval and in vitro matured (67% vs. 46%, P = 0.01). In controls, immature CEOs retrieved with moderate expansion reached higher maturation rates compared to fully compacted CEOs, but in PMC groups, high values of maturation were achieved for both morphological classes of CEOs. No effect of PMC on fertilization was observed. A 24-h PMC period proved to be the most effective in preserving embryonic integrity. Similar proportions of nuclear abnormalities were observed in embryos of all in vitro groups. In summary, PMC with the specific PDE3-I had a beneficial effect on human CEOs by enhancing maturation, benefiting mainly the fully compacted CEOs. This resulted in an increased yield of mature oocytes available for insemination without compromising embryonic development. These results suggest that applying an inhibitor to control the rate of nuclear maturity by regulating intraoocyte PDE3 activity may allow the synchronization of nuclear and ooplasmic maturation.

  2. Pneumomediastinum after Tooth Extraction

    OpenAIRE

    Ilhan Ocakcioglu; Serhat Koyuncu; Mustafa Kupeli; Oguzhan Bol

    2016-01-01

    Pneumomediastinum is defined as the presence of air in mediastinum. Pneumomediastinum can sometimes occur after surgery. Pneumomediastinum seen after dental procedures is rare. We presented the case of subcutaneous emphysema developed in the neck and upper chest after tooth extraction and discussed the possible mechanisms of pneumomediastinum.

  3. Evolution and developmental diversity of tooth regeneration.

    Science.gov (United States)

    Tucker, Abigail S; Fraser, Gareth J

    2014-01-01

    This review considers the diversity observed during both the development and evolution of tooth replacement throughout the vertebrates in a phylogenetic framework from basal extant chondrichthyan fish and more derived teleost fish to mammals. We illustrate the conservation of the tooth regeneration process among vertebrate clades, where tooth regeneration refers to multiple tooth successors formed de novo for each tooth position in the jaws from a common set of retained dental progenitor cells. We discuss the conserved genetic mechanisms that might be modified to promote morphological diversity in replacement dentitions. We review current research and recent progress in this field during the last decade that have promoted our understanding of tooth diversity in an evolutionary developmental context, and show how tooth replacement and dental regeneration have impacted the evolution of the tooth-jaw module in vertebrates.

  4. Orthodontic Tooth Movement: A Historic Prospective.

    Science.gov (United States)

    Will, Leslie A

    2016-01-01

    The earliest report on orthodontic tooth movement in the English literature was published in 1911. Oppenheim carried out studies on baboons to determine what histologic changes occurred during tooth movement. Reitan and many others carried out research into the nature of tooth movement. The pressure-tension model of tooth movement developed from these studies, whereby the two sides of the tooth responded to forces as if in isolation. A second theory, proposed by Stuteville in 1938, was the hydraulic theory of tooth movement. In this theory, fluid from the vasculature, lymphatic system and intercellular spaces responds to the forces of tooth movement, damping the force and limiting movement. Bien and Baumrind expanded on this theory with their own studies in the 1960s. It is clear that both the pressure-tension and fluid flow concepts have merit, but considerable work needs to be done to ascertain the details so that tooth movement can be managed and controlled.

  5. Successful resuscitation of a patient who developed cardiac arrest from pulsed saline bacitracin lavage during thoracic laminectomy and fusion.

    Science.gov (United States)

    Greenberg, Steven B; Deshur, Mark; Khavkin, Yevgeniy; Karaikovic, Elden; Vender, Jeffery

    2008-06-01

    A patient with a history of T12 burst fracture caused by a fall, and with progressive weakness and sensory loss in the left leg, survived a cardiac arrest after pulsed saline bacitracin lavage irrigation during a posterior spinal fusion.

  6. Shh信号通路在牙早期发育中的研究进展%Advances about Shh signaling pathway during early tooth development

    Institute of Scientific and Technical Information of China (English)

    赵武奎; 林恒; 黄心怡; 李汉梁; 林程琳; 王冰梅

    2012-01-01

    Sonic hedgehog (Shh)信号通路在牙早期发育中起关键作用,Shh通过与其特定的受体Ptc/Smo蛋白复合物相互作用来激活整个信号通路.Shh在牙早期发育过程中的表达具有时间和空间特异性,通过自分泌和旁分泌作用于上皮组织以及周围的间充质,促进细胞增殖、分化,调控牙的形态发生.Shh基因缺失将导致小鼠在帽状期牙形态的严重畸形,牙体变小,牙索缺失.对Shh信号通路在牙早期发育的作用及其与Wnt信号通路、BMP家族、FGF家族和MSX家族之间的相互关系进行综述.%Sonic hedgehog (Shh) signaling pathway plays a critical role during the early tooth development. Shh activates the whole signaling pathway via interacting with its specific receptor, Ptc/Smo protein complex. During the early tooth development process, Shh expresses in a temporal and spatial specific manner, affects the epithelial and mesenchymal dental tissues through autocrine and paracrine, promotes cell proliferation and differentiation, and then regulates the tooth morphogenesis. Shh gene deletion will result in severely abnormal tooth morphology, reduce tooth size and dental cord absence during the cap stage in mouse. This present review mainly discussed the role of Shh signaling pathway in early tooth development and its interrelationship with Wnt signaling, and BMP, FGF and MSX families.

  7. Age estimation and the developing third molar tooth: an analysis of an Australian population using computed tomography.

    Science.gov (United States)

    Bassed, Richard B; Briggs, C; Drummer, Olaf H

    2011-09-01

    The third molar tooth is one of the few anatomical sites available for age estimation of unknown age individuals in the late adolescent years. Computed tomography (CT) images were assessed in an Australian population aged from 15 to 25 years for development trends, particularly concerning age estimation at the child/adult transition point of 18 years. The CT images were also compared to conventional radiographs to assess the developmental scoring agreement between the two and it was found that agreement of Demirjian scores between the two imaging modalities was excellent. The relatively wide age ranges (mean ± 2SD) indicate that the third molar is not a precise tool for age estimation (age ranges of 3-8 years) but is, however, a useful tool for discriminating the adult/child transition age of 18 years. In the current study 100% of females and 96% of males with completed roots were over 18 years of age.

  8. [Tooth regeneration--dream to reality].

    Science.gov (United States)

    Wang, Song-Ling; Wang, Xue-Jiu

    2008-04-01

    Tooth or dentition missing compromises human health physically and psychiatrically. Although several prosthesis methods are used to restore tooth loss, these restorations are still non-biological methods. It is a dream for human being to regenerate a real tooth for hundreds years. There are two ways to regenerate the tooth. One is application of conventional tissue engineering techniques including seed cells and scaffold. The other is regeneration tooth using dental epithelium and dental mesenchymal cells based on the knowledge of tooth initiation and development. Marked progress has been achieved in these two ways, while there is still a long way to go. Recently a new concept has been proposed for regeneration of a biological tooth root based on tooth-related stem cells and tissue engineering technique. A biological tooth root has been regenerated in swine. It may be a valuable method for restoration of tooth loss before successful whole tooth regeneration. A latest research showed that a subpopulation in bone marrow cells can give rise to ameloblast-like cells when mixed with embryonic epithelium and reassociation with integrated mesenchyme, which may provide a new seed cell source for tooth regeneration.

  9. Metoclopramide-induced cardiac arrest

    Directory of Open Access Journals (Sweden)

    Martha M. Rumore

    2011-11-01

    Full Text Available The authors report a case of cardiac arrest in a patient receiving intravenous (IV metoclopramide and review the pertinent literature. A 62-year-old morbidly obese female admitted for a gastric sleeve procedure, developed cardiac arrest within one minute of receiving metoclopramide 10 mg via slow intravenous (IV injection. Bradycardia at 4 beats/min immediately appeared, progressing rapidly to asystole. Chest compressions restored vital function. Electrocardiogram (ECG revealed ST depression indicative of myocardial injury. Following intubation, the patient was transferred to the intensive care unit. Various cardiac dysrrhythmias including supraventricular tachycardia (SVT associated with hypertension and atrial fibrillation occurred. Following IV esmolol and metoprolol, the patient reverted to normal sinus rhythm. Repeat ECGs revealed ST depression resolution without pre-admission changes. Metoclopramide is a non-specific dopamine receptor antagonist. Seven cases of cardiac arrest and one of sinus arrest with metoclopramide were found in the literature. The metoclopramide prescribing information does not list precautions or adverse drug reactions (ADRs related to cardiac arrest. The reaction is not dose related but may relate to the IV administration route. Coronary artery disease was the sole risk factor identified. According to Naranjo, the association was possible. Other reports of cardiac arrest, severe bradycardia, and SVT were reviewed. In one case, five separate IV doses of 10 mg metoclopramide were immediately followed by asystole repeatedly. The mechanism(s underlying metoclopramide’s cardiac arrest-inducing effects is unknown. Structural similarities to procainamide may play a role. In view of eight previous cases of cardiac arrest from metoclopramide having been reported, further elucidation of this ADR and patient monitoring is needed. Our report should alert clinicians to monitor patients and remain diligent in surveillance and

  10. High fat diet triggers cell cycle arrest and excessive apoptosis of granulosa cells during the follicular development.

    Science.gov (United States)

    Wu, Yanqing; Zhang, Zhenghong; Liao, Xinghui; Wang, Zhengchao

    2015-10-23

    The regulatory mechanism of granulosa cells (GCs) proliferation during the follicular development is complicated and multifactorial, which is essential for the oocyte growth and normal ovarian functions. To investigate the role of high fat diet (HFD) on the proliferation of GCs, 4-week old female mice were fed with HFD or normal control diet (NC) for 15 weeks or 20 weeks and then detected the expression level of some regulatory molecules of cell cycle and apoptosis. The abnormal ovarian morphology was observed at 20 weeks. Further mechanistic studies indicated that HFD induced-obesity caused elevated apoptotic levels in GCs of the ovaries in a time-dependent manner. Moreover, cell cycle progress was also impacted after HFD fed. The cell cycle inhibitors, p27(Kip1) and p21(Cip1), were significantly induced in the ovaries from the mice in HFD group when compared with that in the ovaries from the mice in NC group. Subsequently, the expression levels of Cyclin D1, D3 and CDK4 were also significantly influenced in the ovaries from the mice fed with HFD in a time-dependent manner. The present results suggested that HFD induced-obesity may trigger cell cycle arrest and excessive apoptosis of GCs, causing the abnormal follicular development and ovarian function failure.

  11. Novel human mutation and CRISPR/Cas genome-edited mice reveal the importance of C-terminal domain of MSX1 in tooth and palate development.

    Science.gov (United States)

    Mitsui, Silvia Naomi; Yasue, Akihiro; Masuda, Kiyoshi; Naruto, Takuya; Minegishi, Yoshiyuki; Oyadomari, Seiichi; Noji, Sumihare; Imoto, Issei; Tanaka, Eiji

    2016-12-05

    Several mutations, located mainly in the MSX1 homeodomain, have been identified in non-syndromic tooth agenesis predominantly affecting premolars and third molars. We identified a novel frameshift mutation of the highly conserved C-terminal domain of MSX1, known as Msx homology domain 6 (MH6), in a Japanese family with non-syndromic tooth agenesis. To investigate the importance of MH6 in tooth development, Msx1 was targeted in mice with CRISPR/Cas system. Although heterozygous MH6 disruption did not alter craniofacial development, homozygous mice exhibited agenesis of lower incisors with or without cleft palate at E16.5. In addition, agenesis of the upper third molars and the lower second and third molars were observed in 4-week-old mutant mice. Although the upper second molars were present, they were abnormally small. These results suggest that the C-terminal domain of MSX1 is important for tooth and palate development, and demonstrate that that CRISPR/Cas system can be used as a tool to assess causality of human disorders in vivo and to study the importance of conserved domains in genes.

  12. 经典Wnt信号通路在牙齿发育中的研究新进展%Recent advances About Canonical Wnt Pathway in Tooth Development

    Institute of Scientific and Technical Information of China (English)

    王也; 李汉梁; 林丽娣; 林鑫; 王冰梅

    2011-01-01

    Canonical Wnt signaling pathway is one of the main four categories of signal transduction pathway involving in embrvo and organ development. It also plays an important role in the tooth development. In this paper, we briefly write an overview about the new research of β -catenin,Lefl,Apc,Axin2 in tooth development: β -catenin affects the interaction between epithelium and mesenchyme by regulating other signals; the LEF/TCF complex can regulate the fate of dental epithelium cell; Apc inhibits supernumerary tooth formation during embryo genesis; and Axin2 has the influence of development of the crown and root during pre- and postnatal tooth development. So here we hope it may bring a new breakthrough among tooth regeneration and other bioengineerings.%经典Wnt信号通路是参与胚胎及器官发育的四大信号传导途径之一,在牙齿发育中扮演了重要的角色.本文对其中的β-catenin,Lefl,Apc,Axin2这4个关键因子在牙齿发育中研究的新进展做了简要的概述:β-catenin在间充质中会调控多个信号,影响牙上皮和间充质相互作用;Lefl会和Tcf家族一道调控上皮细胞命运;Apc能抑制多余牙齿的形成;Axin2在牙晚期发育中影响牙本质的形成.通过这些因子的研究,希望人们能在牙齿再生等生物医学工程上有新的突破.

  13. Embryonic Lethality Due to Arrested Cardiac Development in Psip1/Hdgfrp2 Double-Deficient Mice.

    Directory of Open Access Journals (Sweden)

    Hao Wang

    Full Text Available Hepatoma-derived growth factor (HDGF related protein 2 (HRP2 and lens epithelium-derived growth factor (LEDGF/p75 are closely related members of the HRP2 protein family. LEDGF/p75 has been implicated in numerous human pathologies including cancer, autoimmunity, and infectious disease. Knockout of the Psip1 gene, which encodes for LEDGF/p75 and the shorter LEDGF/p52 isoform, was previously shown to cause perinatal lethality in mice. The function of HRP2 was by contrast largely unknown. To learn about the role of HRP2 in development, we knocked out the Hdgfrp2 gene, which encodes for HRP2, in both normal and Psip1 knockout mice. Hdgfrp2 knockout mice developed normally and were fertile. By contrast, the double deficient mice died at approximate embryonic day (E 13.5. Histological examination revealed ventricular septal defect (VSD associated with E14.5 double knockout embryos. To investigate the underlying molecular mechanism(s, RNA recovered from ventricular tissue was subjected to RNA-sequencing on the Illumina platform. Bioinformatic analysis revealed several genes and biological pathways that were significantly deregulated by the Psip1 knockout and/or Psip1/Hdgfrp2 double knockout. Among the dozen genes known to encode for LEDGF/p75 binding factors, only the expression of Nova1, which encodes an RNA splicing factor, was significantly deregulated by the knockouts. However the expression of other RNA splicing factors, including the LEDGF/p52-interacting protein ASF/SF2, was not significantly altered, indicating that deregulation of global RNA splicing was not a driving factor in the pathology of the VSD. Tumor growth factor (Tgf β-signaling, which plays a key role in cardiac morphogenesis during development, was the only pathway significantly deregulated by the double knockout as compared to control and Psip1 knockout samples. We accordingly speculate that deregulated Tgf-β signaling was a contributing factor to the VSD and prenatal lethality

  14. Epigenetics in tooth development and its implication in tooth regeneration%表观遗传在牙发生和牙再生中的作用及意义

    Institute of Scientific and Technical Information of China (English)

    周晨; 凌均棨

    2016-01-01

    表观遗传是指DNA序列不发生变化,基因表达却发生了可遗传改变的一种遗传方式,主要涉及DNA甲基化和组蛋白的不同翻译后修饰,决定了特定的基因表达形式。DNA甲基化常引起基因表达抑制,而脱甲基化则引起基因表达开放。组蛋白有众多的共价修饰形式,根据修饰的种类、位点及个数的不同,引起基因沉默或激活。表观遗传修饰是细胞定向分化和重编程中基因特异性表达的重要调控方式,在机体发生中扮演着重要的角色。在牙发生过程中,表观遗传与传统的基因表达调控协同,调节细胞增殖、分化和迁移相关基因的时空表达,最后导致牙的形成。诠释牙发生过程中的表观遗传调控机制,无疑可为牙再生提供关键的线索和思路。%Epigenetics, mainly including DNA methylation and histone post-translational modification, is the heritable changes that are not caused by changes in the DNA sequence; this change also alters how genes are expressed. DNA methylation typically causes gene transcriptional silencing, whereas demethylation leads to transcription activation. A large number of covalent modifications on histone, such as different types, residues, and amount, will affect the inhibition or activation of gene expression. Epigenetic modifications play pivotal roles in organogenesis by controlling gene expression during cell fate determination and reprogramming. In the process of tooth development, complex orchestration between genetic and epigenetic programs regulates the spatiotemporal expression of cell proliferation-, differentiation-, and migration-related genes, and finally tooth formation. Exploring the molecular biology of epigenetic, together with the epigenetic findings in tooth development, is not only fundamental but also inspiring for tooth regeneration.

  15. Cell-cell interactions in tooth development%细胞间连接在牙发育中的作用

    Institute of Scientific and Technical Information of China (English)

    吴煜

    2011-01-01

    Tooth development involves a series of interactions between the oral epithelium and cranial neural crest-derived mesenchymal cells. These interactions progressively transform the tooth primordia into complex mineralized structures. Cell-cell interactions play complementary roles in allowing plasticity during tooth morphogenesis and stabilization at later stages of epithelial histogenesis. This article reviews the role of cell-cell interactions mediated by adherens junctions formed by cadherins and communicative gap junctions formed by connexins in regulating tooth development.%口腔上皮和源于颅神经嵴的间叶细胞间相互作用,牙原基发育形成为复杂的钙化组织.细胞间复杂有序地相互作用导致牙形态发生并保持稳定.本文就牙发育过程中参与细胞间相互作用的黏附连接与钙黏着蛋白、钙黏着蛋白与牙发育,缝隙连接与缝隙连接蛋白、缝隙连接蛋白与牙发育等研究进展作一综述.

  16. Dental implant as an option for tooth replacement: The awareness of patients at a tertiary hospital in a developing country

    Directory of Open Access Journals (Sweden)

    Olaide Shakeerah Gbadebo

    2014-01-01

    Full Text Available Aim: A survey was set out to evaluate the knowledge of patients about tooth replacement as a whole, and assess their awareness of implant-retained prosthesis as an option of tooth replacement. Materials and Methods: Information on sociodemographic characteristics, knowledge about implant-retained tooth as an option for missing tooth replacement, cost implication, source of information and knowledge about other options of tooth replacement were obtained from patients attending the dental clinics of the University College Hospital, Ibadan, using structured self-administered questionnaires. Data were analyzed using SPSS version 20. Result: A total of 220 patients aged 18-84 years with a mean age of 37.6 (±16.5 years participated in the study, with a male to female ratio of 1:1.1. The majority (92.5% knew that missing teeth can be replaced, while a significantly lower proportion (28.9% knew about dental implants as an option (P < 0.01. Dentists were the major source of information on dental implants (68%. Only 21 (36.8% of those who had heard about dental implant had knowledge about the cost (P < 0.000. Conclusion: A low level of awareness about dental implant as tooth replacement option exist in this environment, although most of the study participants were aware that missing teeth can be replaced.

  17. Evolution of high tooth replacement rates in sauropod dinosaurs.

    Directory of Open Access Journals (Sweden)

    Michael D D'Emic

    Full Text Available BACKGROUND: Tooth replacement rate can be calculated in extinct animals by counting incremental lines of deposition in tooth dentin. Calculating this rate in several taxa allows for the study of the evolution of tooth replacement rate. Sauropod dinosaurs, the largest terrestrial animals that ever evolved, exhibited a diversity of tooth sizes and shapes, but little is known about their tooth replacement rates. METHODOLOGY/PRINCIPAL FINDINGS: We present tooth replacement rate, formation time, crown volume, total dentition volume, and enamel thickness for two coexisting but distantly related and morphologically disparate sauropod dinosaurs Camarasaurus and Diplodocus. Individual tooth formation time was determined by counting daily incremental lines in dentin. Tooth replacement rate is calculated as the difference between the number of days recorded in successive replacement teeth. Each tooth family in Camarasaurus has a maximum of three replacement teeth, whereas each Diplodocus tooth family has up to five. Tooth formation times are about 1.7 times longer in Camarasaurus than in Diplodocus (315 vs. 185 days. Average tooth replacement rate in Camarasaurus is about one tooth every 62 days versus about one tooth every 35 days in Diplodocus. Despite slower tooth replacement rates in Camarasaurus, the volumetric rate of Camarasaurus tooth replacement is 10 times faster than in Diplodocus because of its substantially greater tooth volumes. A novel method to estimate replacement rate was developed and applied to several other sauropodomorphs that we were not able to thin section. CONCLUSIONS/SIGNIFICANCE: Differences in tooth replacement rate among sauropodomorphs likely reflect disparate feeding strategies and/or food choices, which would have facilitated the coexistence of these gigantic herbivores in one ecosystem. Early neosauropods are characterized by high tooth replacement rates (despite their large tooth size, and derived titanosaurs and

  18. UCSF Protocol for Caries Arrest Using Silver Diamine Fluoride: Rationale, Indications, and Consent

    Science.gov (United States)

    Horst, Jeremy A; Ellenikiotis, Hellene; Milgrom, Peter M

    2016-01-01

    The Food and Drug Administration recently cleared silver diamine fluoride for reducing tooth sensitivity. Clinical trials document arrest and prevention of dental caries by silver diamine fluoride; this off-label use is now permissible and appropriate under U.S. law. A CDT code was approved for caries arresting medicaments for 2016 to facilitate documentation and billing. We present a systematic review, clinical indications, clinical protocol, and consent procedure to guide application for caries arrest treatment. PMID:26897901

  19. Fate of fluoride-induced subameloblastic cysts in developing hamster molar tooth germs

    NARCIS (Netherlands)

    Lyaruu, D.M.; Alberga, J.M.R.; Kwee, N.C.H.; Bervoets, T.J.M.; Bronckers, A.L.J.J.; Denbesten, P.K.

    2011-01-01

    White opacities and pits are developmental defects in enamel caused by high intake of fluoride (F) during amelogenesis. We tested the hypothesis that these enamel pits develop at locations where F induces the formation of sub-ameloblastic cysts. We followed the fate of these cysts during molar devel

  20. Impaired tooth root development after treatment of a cerebellar astrocytoma: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Eckles, T.A.; Kalkwarf, K.L.

    1989-10-01

    A young man, previously treated by surgical resection of a grade III cerebellar astrocytoma in combination with irradiation and chemotherapy, was found to display severe generalized root agenesis. This patient also exhibited secondary hypothyroidism and decreased levels of growth hormone. These factors are discussed in relation to their possible role in impaired root development.

  1. The anterior tooth development of cattle presented for slaughter: an analysis of age, sex and breed.

    Science.gov (United States)

    Whiting, K J; Brown, S N; Browne, W J; Hadley, P J; Knowles, T G

    2013-08-01

    In a cross-sectional study, data from records of cattle slaughtered over a 1-year period at a large abattoir in South West England were analysed using an ordered category response model to investigate the inter-relationships between age, sex and breed on development of the permanent anterior (PA) teeth. Using the model, transition points at which there was a 50% probability of membership of each category of paired PA teeth were identified. Data from ∼60,000 animals were initially analysed for age and sex effect. The age transition was found to be ∼23 months moving from zero to two teeth; 30 months for two to four teeth; 37 months for four to six teeth and 42 months for six to eight teeth. Males were found to develop, on average, ∼22 days earlier than females across all stages. A reduced data set of ∼23,000 animals registered as pure-bred only was used to compare breed and type interactions and to investigate sex effects within the sub-categories. Breeds were grouped into dairy and beef-type and beef breeds split into native and continental. It was found that dairy-types moved through the transition points earlier than beef-types across all stages (interval varying between ∼8 and 12 weeks) and that collectively, native beef breeds moved through the transition points by up to 3 weeks earlier than the continental beef breeds. Interestingly, in contrast to beef animals, dairy females matured before dairy males. However, the magnitude of the difference between dairy females and males diminished at the later stages of development. Differences were found between breeds. Across the first three stages, Ayrshires and Guernseys developed between 3 and 6 weeks later than Friesian/Holsteins and Simmental, Limousin and Blonde Aquitaine 6 and 8 weeks later than Aberdeen Angus. Herefords, Charolais and South Devon developed later but by a smaller interval and Red Devon and Galloway showed the largest individual effect with transition delayed by 8 to 12 weeks.

  2. Develop mono-block tooth implants using automate design and FEM analysis

    OpenAIRE

    J.P. Alister; J. Moller,; F. Alister; R. Hunter

    2007-01-01

    Purpose: Purpose of this paper is present a new approach to modelling and design the low cost mono-block dental implants based on the integration of the computer aided techniques. This approach provides the automation of the design process of the mono-block dental implants.Design/methodology/approach: The approach used to develop the modelling and design of the mono-block dental implants are based on the parametrization of the main geometric features of the implants. This approach allows to ...

  3. Micro-PIGE determination of fluorine distribution in developing hamster tooth germs.

    Science.gov (United States)

    Lyaruu, D M; Lenglet, W J; Wöltgens, J H; Bronckers, A L

    1989-05-01

    A micro-PIGE (Proton-Induced gamma-ray Emission) technique based on the delayed 5/2+----1/2+ nuclear transition of fluorine (E gamma = 197 keV, t1/2 = 87 ns) emitted after 19F(p,p', gamma)19F reaction was used to detect and study the distribution of fluorine in the developing enamel organ during pre-eruptive stages, i.e., the transitional to early maturation stages of enamel formation in neonatal hamsters administered a single IP dose of sodium fluoride (20 mg NaF/kg body weight). The aforementioned nuclear reaction is unique for fluorine, and therefore detection of gamma-rays emanating from this reaction in a biological specimen implies a positive identification of fluorine at that particular site. Calcium and phosphorus X-rays were also recorded and used as parameters for assessment of the relationship between the degree of mineralization and fluoride incorporation into the enamel organ. The highest fluorine concentration in the enamel organ was recorded in the dentin near the dentin-enamel junction (DEJ). In the enamel, the highest concentration of fluorine was found to be associated with the more mature areas of the enamel near the DEJ, but gradually decreased in the direction of the enamel surface. Fluorine was not detected in the control germs. These results suggest that administration of fluoride in high doses during the pre-eruptive stages of enamel formation leads to incorporation of the ion into the forming dentin and enamel mineral, and that the enamel matrix does not seem to bind fluoride avidly.

  4. Tooth sensitivity and whitening.

    Science.gov (United States)

    Swift, Edward J

    2005-09-01

    This article presents a review of the basic concepts of tooth sensitivity and how those concepts apply to cervical dentin hypersensitivity and the sensitivity frequently associated with tooth whitening. The etiology and treatment of cervical dentin hypersensitivity are described. The clinical presentation, incidence, and predisposing factors for sensitivity associated with tooth whitening also are discussed.

  5. Distribution of Cathepsin K in Late Stage of Tooth Germ Development and Its Function in Degrading Enamel Matrix Proteins in Mouse.

    Science.gov (United States)

    Jiang, Tao; Liu, Fen; Wang, Wei-Guang; Jiang, Xin; Wen, Xuan; Hu, Kai-Jin; Xue, Yang

    2017-01-01

    Cathepsin K (CTSK) is a member of cysteine proteinase family, and is predominantly expressed in osteoclastsfor degradationof bone matrix proteins. Given the similarity in physical properties of bone and dental mineralized tissues, including enamel, dentin and cementum, CTSK is likely to take part in mineralization process during odontogenesis. On the other hand, patients with pycnodysostosis caused by mutations of the CTSK gene displayedmultipledental abnormalities, such as hypoplasia of the enamel, obliterated pulp chambers, hypercementosis and periodontal disease. Thereforeitis necessary to study the metabolic role of CTSK in tooth matrix proteins. In this study, BALB/c mice at embryonic day 18 (E18), post-natal day 1 (P1), P5, P10 and P20 were used (5 mice at each time point)for systematic analyses of CTSK expression in the late stage of tooth germ development. We found that CTSK was abundantly expressed in the ameloblasts during secretory and maturation stages (P5 and P10) by immunohistochemistry stainings.During dentinogenesis, the staining was also intense in the mineralization stage (P5 and P10),but not detectable in the early stage of dentin formation (P1) and after tooth eruption (P20).Furthermore, through zymography and digestion test in vitro, CTSK was proved to be capable of hydrolyzing Emdogain and also cleaving Amelogenininto multiple products. Our resultsshed lights on revealing new functions of CTSK and pathogenesis of pycnodysostosis in oral tissues.

  6. Distribution of Cathepsin K in Late Stage of Tooth Germ Development and Its Function in Degrading Enamel Matrix Proteins in Mouse

    Science.gov (United States)

    Jiang, Tao; Liu, Fen; Wang, Wei-Guang; Jiang, Xin; Wen, Xuan; Hu, Kai-Jin; Xue, Yang

    2017-01-01

    Cathepsin K (CTSK) is a member of cysteine proteinase family, and is predominantly expressed in osteoclastsfor degradationof bone matrix proteins. Given the similarity in physical properties of bone and dental mineralized tissues, including enamel, dentin and cementum, CTSK is likely to take part in mineralization process during odontogenesis. On the other hand, patients with pycnodysostosis caused by mutations of the CTSK gene displayedmultipledental abnormalities, such as hypoplasia of the enamel, obliterated pulp chambers, hypercementosis and periodontal disease. Thereforeitis necessary to study the metabolic role of CTSK in tooth matrix proteins. In this study, BALB/c mice at embryonic day 18 (E18), post-natal day 1 (P1), P5, P10 and P20 were used (5 mice at each time point)for systematic analyses of CTSK expression in the late stage of tooth germ development. We found that CTSK was abundantly expressed in the ameloblasts during secretory and maturation stages (P5 and P10) by immunohistochemistry stainings.During dentinogenesis, the staining was also intense in the mineralization stage (P5 and P10),but not detectable in the early stage of dentin formation (P1) and after tooth eruption (P20).Furthermore, through zymography and digestion test in vitro, CTSK was proved to be capable of hydrolyzing Emdogain and also cleaving Amelogenininto multiple products. Our resultsshed lights on revealing new functions of CTSK and pathogenesis of pycnodysostosis in oral tissues. PMID:28095448

  7. Dental Calculus Arrest of Dental Caries

    Science.gov (United States)

    Keyes, Paul H.; Rams, Thomas E.

    2016-01-01

    Background An inverse relationship between dental calculus mineralization and dental caries demineralization on teeth has been noted in some studies. Dental calculus may even form superficial layers over existing dental caries and arrest their progression, but this phenomenon has been only rarely documented and infrequently considered in the field of Cariology. To further assess the occurrence of dental calculus arrest of dental caries, this study evaluated a large number of extracted human teeth for the presence and location of dental caries, dental calculus, and dental plaque biofilms. Materials and methods A total of 1,200 teeth were preserved in 10% buffered formal saline, and viewed while moist by a single experienced examiner using a research stereomicroscope at 15-25× magnification. Representative teeth were sectioned and photographed, and their dental plaque biofilms subjected to gram-stain examination with light microscopy at 100× magnification. Results Dental calculus was observed on 1,140 (95%) of the extracted human teeth, and no dental carious lesions were found underlying dental calculus-covered surfaces on 1,139 of these teeth. However, dental calculus arrest of dental caries was found on one (0.54%) of 187 evaluated teeth that presented with unrestored proximal enamel caries. On the distal surface of a maxillary premolar tooth, dental calculus mineralization filled the outer surface cavitation of an incipient dental caries lesion. The dental calculus-covered carious lesion extended only slightly into enamel, and exhibited a brown pigmentation characteristic of inactive or arrested dental caries. In contrast, the tooth's mesial surface, without a superficial layer of dental calculus, had a large carious lesion going through enamel and deep into dentin. Conclusions These observations further document the potential protective effects of dental calculus mineralization against dental caries. PMID:27446993

  8. Whole Tooth Regeneration as a Future Dental Treatment.

    Science.gov (United States)

    Oshima, Masamitsu; Tsuji, Takashi

    2015-01-01

    Dental problems caused by dental caries, periodontal disease and tooth injury compromise the oral and general health issues. Current advances for the development of regenerative therapy have been influenced by our understanding of embryonic development, stem cell biology, and tissue engineering technology. Tooth regenerative therapy for tooth tissue repair and whole tooth replacement is currently expected a novel therapeutic concept with the full recovery of tooth physiological functions. Dental stem cells and cell-activating cytokines are thought to be candidate approach for tooth tissue regeneration because they have the potential to differentiate into tooth tissues in vitro and in vivo. Whole tooth replacement therapy is considered to be an attractive concept for next generation regenerative therapy as a form of bioengineered organ replacement. For realization of whole tooth regeneration, we have developed a novel three-dimensional cell manipulation method designated the "organ germ method". This method involves compartmentalisation of epithelial and mesenchymal cells at a high cell density to mimic multicellular assembly conditions and epithelial-mesenchymal interactions in organogenesis. The bioengineered tooth germ generates a structurally correct tooth in vitro, and erupted successfully with correct tooth structure when transplanted into the oral cavity. We have ectopically generated a bioengineered tooth unit composed of a mature tooth, periodontal ligament and alveolar bone, and that tooth unit was engrafted into an adult jawbone through bone integration. Bioengineered teeth were also able to perform physiological tooth functions such as mastication, periodontal ligament function and response to noxious stimuli. In this review, we describe recent findings and technologies underpinning whole tooth regenerative therapy.

  9. Tooth crown heights, tooth wear, sexual dimorphism and jaw growth in hominoids.

    Science.gov (United States)

    Dean, M C; Beynon, A D

    1991-01-01

    The aim of this review is to bring together data that link tooth morphology with tooth function and tooth growth: We aim to show how the microanatomy of hominoid teeth is providing evidence about rates of tooth growth that are likely to be a consequence of both masticatory strategy and social behaviour. First, we present data about incisor and molar tooth wear in wild short chimpanzees that demonstrate how crown heights are likely to be related to relative tooth use in a broad sense. Following this we review recent studies that describe the microanatomy of hominoid tooth enamel and show how these studies are providing evidence about tooth crown formation times in hominoids, as well as improving estimates for the age at death of certain juvenile fossil hominids. Next, we outline what is known about the mechanisms of tooth growth in the sexually dimorphic canine teeth of chimpanzees and compare these patterns of growth with tooth growth patterns in the canines of three fossil hominids from Laetoli, Tanzania. Finally, we discuss how selection pressures that operate to increase or reduce the size of anterior teeth interact with jaw size. We argue that the space available to grow developing teeth in the mandibles of juvenile hominoids is determined by the growth patterns of the mandibles, which in turn reflect masticatory strategy. The consequences of selection pressure to grow large or small anterior teeth are likely to be reflected in the times at which these teeth are able to emerge into occlusion.

  10. Impacted tooth

    Science.gov (United States)

    ... 2016 Updated by: Michael Kapner, DDS, general and aesthetic dentistry, Norwalk Medical Center, Norwalk, CT. Review provided ... for EHRs For Developers U.S. National Library of Medicine 8600 Rockville Pike, Bethesda, MD 20894 U.S. Department ...

  11. Tooth abscess

    Science.gov (United States)

    ... 2016 Updated by: Michael Kapner, DDS, general and aesthetic dentistry, Norwalk Medical Center, Norwalk, CT. Review provided ... for EHRs For Developers U.S. National Library of Medicine 8600 Rockville Pike, Bethesda, MD 20894 U.S. Department ...

  12. Research progress on the role of Dkk-Wnt signaling pathway on tooth development%Dkk-Wnt信号通路在牙齿发育中作用的研究进展

    Institute of Scientific and Technical Information of China (English)

    吴也可

    2012-01-01

    Mammalian tooth development is largely dependent on the sequential and reciprocal epithelial-mesenchymal interaction. Dkk-Wnt signaling pathway has become a hot point in the research field of tooth development. Dkk-Wnt signaling is proved to be critical in the process of tooth-forming cells functioning, tooth patterning, tooth morphogenesis and crown calcification. Elucidation of molecular mechanisms involved in tooth development will surely provide theoretical basis for translational clinical application of tissue engineering strategies such as tooth regeneration. This article is committed to review on the research progress regarding the role of Wnt signaling pathway on tooth development in recent years.%哺乳动物的牙齿发育是外胚层上皮与间充质间相互调控和信号交流的结果,其中Dkk-Wnt信号通路是近年来牙胚发育研究领域的热点.Dkk-Wnt信号通路已被证实在牙体形成细胞功能的发挥、牙齿模式化、形态发生、牙冠钙化过程中扮演重要作用.牙齿发生发育分子机制的深入研究,将为牙再生组织工程技术以及相关技术的临床转化提供理论基础.本文就近十年对Wnt信号通路在牙齿发育中所起作用的研究作一综述.

  13. Development of cell-based quantitative evaluation method for cell cycle-arrest type cancer drugs for apoptosis by high precision surface plasmon resonance sensor

    Science.gov (United States)

    Ona, Toshihiro; Nishijima, Hiroshi; Kosaihira, Atsushi; Shibata, Junko

    2008-04-01

    In vitro rapid and quantitative cell-based assay is demanded to verify the efficacy prediction of cancer drugs since a cancer patient may have unconventional aspects of tumor development. Here, we show the rapid and non-label quantitative verifying method and instrumentation of apoptosis for cell cycle-arrest type cancer drugs (Roscovitine and D-allose) by reaction analysis of living liver cancer cells cultured on a sensor chip with a newly developed high precision (50 ndeg s -1 average fluctuation) surface plasmon resonance (SPR) sensor. The time-course cell reaction as the SPR angle change rate for 10 min from 30 min cell culture with a drug was significantly related to cell viability. By the simultaneous detection of differential SPR angle change and fluorescence by specific probes using the new instrument, the SPR angle was related to the nano-order potential decrease in inner mitochondrial membrane potential. The results obtained are universally valid for the cell cycle-arrest type cancer drugs, which mediate apoptosis through different cell-signaling pathways, by a liver cancer cell line of Hep G2 (Pcancer cells from patients in clinical use.

  14. Regenerative Applications Using Tooth Derived Stem Cells in Other Than Tooth Regeneration: A Literature Review.

    Science.gov (United States)

    Park, Yun-Jong; Cha, Seunghee; Park, Young-Seok

    2016-01-01

    Tooth derived stem cells or dental stem cells are categorized according to the location from which they are isolated and represent a promising source of cells for regenerative medicine. Originally, as one kind of mesenchymal stem cells, they are considered an alternative of bone marrow stromal cells. They share many commonalties but maintain differences. Considering their original function in development and the homeostasis of tooth structures, many applications of these cells in dentistry have aimed at tooth structure regeneration; however, the application in other than tooth structures has been attempted extensively. The availability from discarded or removed teeth can be an innate benefit as a source of autologous cells. Their origin from the neural crest results in exploitation of neurological and numerous other applications. This review briefly highlights current and future perspectives of the regenerative applications of tooth derived stem cells in areas beyond tooth regeneration.

  15. Developing an analytical tool for evaluating EMS system design changes and their impact on cardiac arrest outcomes: combining geographic information systems with register data on survival rates

    Directory of Open Access Journals (Sweden)

    Sund Björn

    2013-02-01

    Full Text Available Abstract Background Out-of-hospital cardiac arrest (OHCA is a frequent and acute medical condition that requires immediate care. We estimate survival rates from OHCA in the area of Stockholm, through developing an analytical tool for evaluating Emergency Medical Services (EMS system design changes. The study also is an attempt to validate the proposed model used to generate the outcome measures for the study. Methods and results This was done by combining a geographic information systems (GIS simulation of driving times with register data on survival rates. The emergency resources comprised ambulance alone and ambulance plus fire services. The simulation model predicted a baseline survival rate of 3.9 per cent, and reducing the ambulance response time by one minute increased survival to 4.6 per cent. Adding the fire services as first responders (dual dispatch increased survival to 6.2 per cent from the baseline level. The model predictions were validated using empirical data. Conclusion We have presented an analytical tool that easily can be generalized to other regions or countries. The model can be used to predict outcomes of cardiac arrest prior to investment in EMS design changes that affect the alarm process, e.g. (1 static changes such as trimming the emergency call handling time or (2 dynamic changes such as location of emergency resources or which resources should carry a defibrillator.

  16. In utero and lactational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) affects tooth development in rhesus monkeys

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, Iku; Kazuhiro, Tsuga; Yasumasa, Akagawa [Hiroshima Univ. (Japan); Mineo, Yasuda; Hiroshi, Sumida [Hiroshima International Univ. (Japan); Akihiro, Arima; Toshio, Ihara [Shin Nippon Biomedical Laboratories, Ltd., Kagoshima (Japan); Shunichiro, Kubota [Tokyo Univ. (Japan); Kazuo, Asaoka [Kyoto Univ., Inuyama (Japan). Primate Research Institute; Takumi, Takasuga [Shimadzu Techno-Research Inc., Kyoto (Japan)

    2004-09-15

    The current tolerable daily intake (TDI) of dioxin and dioxin related compounds has been set at 4 pg TEQ/kg/day in Japan. This value was calculated from the lowest-observed-adverse-effect level (LOAEL) in experimental animals, mostly rodents. Gray et al. reported that a single oral dose of 200 ng/kg of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to pregnant rats on day 15 of gestation resulted in abnormalities of reproductive organs in the offspring. The maternal body burden at this dose was measured to be 86 ng/kg. To attain this body burden level, human daily intake was calculated to be 43.6 pg/kg/day. An uncertainty factor of 10 was applied to this value, and the human TDI was established. However, due to great differences in the biological half life of TCDD between human and rodents, the validity of this calculation is questioned. To obtain more reliable LOAEL in the second generation, we initiated a long-term study in rhesus monkeys in 1999. In rodents, teeth are known to be targets of developmental toxicity of dioxin. In utero and lactational TCDD exposure affects rat incisor and molar development. In humans also tooth abnormalities were reported among populations exposed to dioxins. In our monkey experiment, some young were stillborn or died neonatally. These animals provided us with a unique opportunity to study tooth development in primate young exposed to TCDD in utero and lactationally. By macroscopic observation we found some tooth abnormalities among died young exposed to TCDD5. This prompted us to examine surviving young by radiography. This is an interim report of our findings in these young.

  17. Tooth regeneration: challenges and opportunities for biomedical material research.

    Science.gov (United States)

    Du, Chang; Moradian-Oldak, Janet

    2006-03-01

    Tooth regeneration presents many challenges to researchers in the fields of biology, medicine and material science. This review considers the opportunities for biomedical material research to contribute to this multidisciplinary endeavor. We present short summaries and an overview on the collective knowledge of tooth developmental biology, advances in stem-cell research, and progress in the understanding of the tooth biomineralization principles as they provide the foundation for developing strategies for reparative and regenerative medicine. We emphasize that various biomaterials developed via biomimetic strategies have great potential for tooth tissue engineering and regeneration applications. The current practices in tooth tissue engineering approaches and applications of biomimetic carriers or scaffolds are also discussed.

  18. Pittsburgh Police Arrest Data

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Arrest data contains information on people taken into custody by City of Pittsburgh police officers. More serious crimes such as felony offenses are more likely to...

  19. X-ray micro-analysis of the mineralization patterns in developing enamel in hamster tooth germs exposed to fluoride in vitro during the secretory phase of amelogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Lyaruu, D.M.; Blijleven, N.; Hoeben-Schornagel, K.; Bronckers, A.L.; Woeltgens, J.H.

    1989-09-01

    The developing enamel from three-day-old hamster first maxillary (M1) molar tooth germs exposed to fluoride (F-) in vitro was analyzed for its mineral content by means of the energy-dispersive x-ray microanalysis technique. The aim of this study was to obtain semi-quantitative data on the F(-)-induced hypermineralization patterns in the enamel and to confirm that the increase in electron density observed in micrographs of F(-)-treated enamel is indeed due to an increase in mineral content in the fluorotic enamel. The tooth germs were explanted during the early stages of secretory amelogenesis and initially cultured for 24 hr in the presence of 10 ppm F- in the culture medium. The germs were then cultured for another 24 hr without F-. In order to compare the ultrastructural results directly with the microprobe data, we used the same specimens for both investigations. The net calcium counts (measurement minus background counts) in the analyses were used as a measure of the mineral content in the enamel. The aprismatic pre-exposure enamel, deposited in vivo before the onset of culture, was the most hypermineralized region in the fluorotic enamel, i.e., it contained the highest amount of calcium measured. The degree of the F(-)-induced hypermineralization gradually decreased (but was not abolished) in the more mature regions of the enamel. The unmineralized enamel matrix secreted during the initial F- treatment in vitro mineralized during the subsequent culture without F-. The calcium content in this enamel layer was in the same order of magnitude as that recorded for the newly deposited enamel in control tooth germs cultured without F-.

  20. Cardiac arrest - cardiopulmonary resuscitation

    Institute of Scientific and Technical Information of China (English)

    Basri Lenjani; Besnik Elshani; Nehat Baftiu; Kelmend Pallaska; Kadir Hyseni; Njazi Gashi; Nexhbedin Karemani; Ilaz Bunjaku; Taxhidin Zaimi; Arianit Jakupi

    2014-01-01

    Objective:To investigate application of cardiopulmonary resuscitation(CPR) measures within the golden minutes inEurope.Methods:The material was taken from theUniversityClinical Center ofKosovo -EmergencyCentre inPristina, during the two(2) year period(2010-2011).The collected date belong to the patients with cardiac arrest have been recorded in the patients' log book protocol at the emergency clinic.Results:During the2010 to2011 in the emergency center of theCUCK inPristina have been treated a total of269 patients with cardiac arrest, of whom159 or59.1% have been treated in2010, and110 patients or40.9% in2011.Of the269 patients treated in the emergency centre,93 or34.6% have exited lethally in the emergency centre, and176 or 65.4% have been transferred to other clinics.In the total number of patients with cardiac arrest, males have dominated with186 cases, or69.1%.The average age of patients included in the survey was56.7 year oldSD±16.0 years.Of the269 patients with cardiac arrest, defibrillation has been applied for93 or34.6% of patients.In the outpatient settings defibrillation has been applied for3 or3.2% of patients.Patients were defibrillated with application of one to four shocks. Of27 cases with who have survived cardiac arrest, none of them have suffered cardiac arrest at home,3 or11.1% of them have suffered cardiac arrest on the street, and24 or88.9% of them have suffered cardiac arrest in the hospital.5 out of27 patients survived have ended with neurological impairment.Cardiac arrest cases were present during all days of the week, but frequently most reported cases have been onMonday with32.0% of cases, and onFriday with24.5% of cases. Conclusions:All survivors from cardiac arrest have received appropriate medical assistance within10 min from attack, which implies that if cardiac arrest occurs near an institution health care(with an opportunity to provide the emergent health care) the rate of survival is higher.

  1. Malformations of the tooth root in humans

    Directory of Open Access Journals (Sweden)

    Hans Ulrich eLuder

    2015-10-01

    Full Text Available The most common root malformations in humans arise from either developmental disorders of the root alone or disorders of radicular development as part of a general tooth dysplasia. The aim of this review is to relate the characteristics of these root malformations to potentially disrupted processes involved in radicular morphogenesis. Radicular morphogenesis proceeds under the control of Hertwig's epithelial root sheath (HERS which determines the number, length, and shape of the root, induces the formation of radicular dentin, and participates in the development of root cementum. Formation of HERS at the transition from crown to root development appears to be very insensitive to adverse effects, with the result that rootless teeth are extremely rare. In contrast, shortened roots as a consequence of impaired or prematurely halted apical growth of HERS constitute the most prevalent radicular dysplasia which occurs due to trauma and unknown reasons as well as in association with dentin disorders. While odontoblast differentiation inevitably stops when growth of HERS is arrested, it seems to be unaffected even in cases of severe dentin dysplasias such as regional odontodysplasia and dentin dysplasia type I. As a result radicular dentin formation is at least initiated and progresses for a limited time. The only condition affecting cementogenesis is hypophosphatasia which disrupts the formation of acellular cementum through an inhibition of mineralization. A process particularly susceptible to adverse effects appears to be the formation of the furcation in multirooted teeth. Impairment or disruption of this process entails taurodontism, single-rooted posterior teeth, and misshapen furcations. Thus even though many characteristics of human root malformations can be related to disorders of specific processes involved in radicular morphogenesis, precise inferences as to the pathogenesis of these dysplasias are hampered by the still limited knowledge on

  2. To Tell the Tooth

    Science.gov (United States)

    ... To Tell the Tooth Print and Take a Quiz + Watch Videos Dudley and Friends Sesame Street + For Preteens Healthy Habits Nutrition Be a Dentist + For Educators Career Resources Presentations and Resources Smile Smarts Dental Health Curriculum MouthHealthy Kids > Games and Quizzes > To Tell the Tooth To Tell ...

  3. Nasal tooth: case report

    Energy Technology Data Exchange (ETDEWEB)

    Park, Si Hyun; Kim, Ji Hye; Hwang, Hee Young; Yang, Dal Mo; Kim, Hyung Sik; Park, Chol Heui [Gachon Medical School, Inchon (Korea, Republic of)

    2002-12-01

    Ectopic tooth is not uncommon and usually occurs in the palate and maxillary sinus. We report a case of ectopic tooth located in the nasal cavity, a rare site. The mass depicted by CT was highly attenuated, and central lucency was observed.

  4. Tooth regeneration from newly established cell lines from a molar tooth germ epithelium.

    Science.gov (United States)

    Komine, Akihiko; Suenaga, Momoko; Nakao, Kazuhisa; Tsuji, Takashi; Tomooka, Yasuhiro

    2007-04-13

    In order to investigate tooth development, several cell lines of the dental epithelium and ectomesenchyme have been established. However, no attempt has been reported to regenerate teeth with cell lines. Here, we have established several clonal cell lines of the dental epithelium from a p53-deficient fetal mouse. They expressed specific markers of the dental epithelium such as ameloblastin and amelogenin. A new method has been developed to bioengineer tooth germs with dental epithelial and mesenchymal cells. Reconstructed tooth germs with cell lines and fetal mesenchymal cells were implanted under kidney capsule. The germs regenerated teeth with well-calcified structures as seen in natural tooth. Germs without the cell lines developed bone. This is the first success to regenerate teeth with dental epithelial cell lines. They are useful models in vitro for investigation of mechanisms in morphogenesis and of cell lineage in differentiation, and for clinical application for tooth regeneration.

  5. Determination of tooth clearances at trochoidal pump

    OpenAIRE

    Ivanović, Lozica T.; Erić, Milan D.; Stojanović, Blaža Ž.; id_orcid 0000-0003-4790-2856; Ilić, Andreja B.

    2011-01-01

    The paper describes the development of a mathematical model of trochoidal gearing with clearances. Gearing of a trochoidal pump's gear set with an outer gear having one gear tooth more than an inner gear is analyzed. The inner gear tooth profile is described by peritrochoidal equidistance and the outer gear profile by a circular arc. Upon the basic principles of ideal profile generation, a mathematical model of gearing with clearances is developed. Using an analytical model, the calculation o...

  6. TOOTH CONTACT ANALYSIS OF CONICAL INVOLUTE GEARS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The mathematical model of conical involute gears is developed based on the theory of gearing and the generating mechanism. Tooth contact analysis (TCA) is performed to examine the meshing and bearing contact of the conical involute gear pairs with intersected and crossed axes. In addition, the principal directions and curvatures of the gear surfaces are investigated and the contact ellipses of the mating tooth surfaces are also studied. Finally, the numerical illustrative examples are provided to demonstrate the computational results, test gears are made for tooth-bearing tests, and the conclusion is verified that the theory has the applicability.

  7. Genetics And Tooth Anomalies - An Update

    Directory of Open Access Journals (Sweden)

    Aswathy Brahmanandan

    2013-01-01

    Full Text Available Tooth development like the development of all epithelial appendages is regulated by inductive tissue interactions between epithelium and mesenchyme. Numerous genes interact, either act in conjunction or antagonize each other in odontogenesis. A number of different mesenchymal molecules and their receptors act as mediators in epithelial mesenchymal interactions. Several genes linked with early tooth positioning and developments belong to signaling pathways and have morphogenesis regulatory functions in morphogenesis of other organs. Their mutations often show pleiotropic effects beyond dental morphogenesis. In contrast, certain genes involved in enamel and dentin structures are highly specific for tooth. Mutations in these genes have been identified as causes of Amelogenesis Imperfecta (AI, Dentinogenesis Imperfecta (DI, Dentin Dysplasia (DD and anomalies in tooth number. This article focuses on genetic basis of inherited non-syndromic teeth disorders.

  8. NPPC/NPR2 signaling is essential for oocyte meiotic arrest and cumulus oophorus formation during follicular development in the mouse ovary.

    Science.gov (United States)

    Kiyosu, Chiyo; Tsuji, Takehito; Yamada, Kaoru; Kajita, Shimpei; Kunieda, Tetsuo

    2012-08-01

    Natriuretic peptide type C (NPPC) and its high affinity receptor, natriuretic peptide receptor 2 (NPR2), have been assumed to be involved in female reproduction and have recently been shown to play an essential role in maintaining meiotic arrest of oocytes. However, the overall role of NPPC/NPR2 signaling in female reproduction and ovarian function is still less clear. Here we report the defects observed in oocytes and follicles of mice homozygous for Nppc(lbab) or Npr2(cn), mutant alleles of Nppc or Npr2 respectively to clarify the exact consequences of lack of NPPC/NPR2 signaling in female reproductive systems. We found that: i) Npr2(cn)/Npr2(cn) female mice ovulated a comparable number of oocytes as normal mice but never produced a litter; ii) all ovulated oocytes of Npr2(cn)/Npr2(cn) and Nppc(lbab)/Nppc(lbab) mice exhibited abnormalities, such as fragmented or degenerated ooplasm and never developed to the two-cell stage after fertilization; iii) histological examination of the ovaries of Npr2(cn)/Npr2(cn) and Nppc(lbab)/Nppc(lbab) mice showed that oocytes in antral follicles prematurely resumed meiosis and that immediately before ovulation, oocytes showed disorganized chromosomes or fragmented ooplasm; and iv) ovulated oocytes and oocytes in the periovulatory follicles of the mutant mice were devoid of cumulus cells. These findings demonstrate that NPPC/NPR2 signaling is essential for oocyte meiotic arrest and cumulus oophorus formation, which affects female fertility through the production of oocytes with developmental capacity.

  9. Decellularized Tooth Bud Scaffolds for Tooth Regeneration.

    Science.gov (United States)

    Zhang, W; Vazquez, B; Oreadi, D; Yelick, P C

    2017-01-01

    Whole tooth regeneration approaches currently are limited by our inability to bioengineer full-sized, living replacement teeth. Recently, decellularized organ scaffolds have shown promise for applications in regenerative medicine by providing a natural extracellular matrix environment that promotes cell attachment and tissue-specific differentiation leading to full-sized organ regeneration. We hypothesize that decellularized tooth buds (dTBs) created from unerupted porcine tooth buds (TBs) can be used to guide reseeded dental cell differentiation to form whole bioengineered teeth, thereby providing a potential off-the-shelf scaffold for whole tooth regeneration. Porcine TBs were harvested from discarded 6-mo-old pig jaws, and decellularized by successive sodium dodecyl sulfate/Triton-X cycles. Four types of replicate implants were used in this study: 1) acellular dTBs; 2) recellularized dTBs seeded with porcine dental epithelial cells, human dental pulp cells, and human umbilical vein endothelial cells (recell-dTBs); 3) dTBs seeded with bone morphogenetic protein (BMP)-2 (dTB-BMPs); and 4) freshly isolated nondecellularized natural TBs (nTBs). Replicate samples were implanted into the mandibles of host Yucatan mini-pigs and grown for 3 or 6 mo. Harvested mandibles with implanted TB constructs were fixed in formalin, decalcified, embedded in paraffin, sectioned, and analyzed via histological methods. Micro-computed tomography (CT) analysis was performed on harvested 6-mo samples prior to decalcification. All harvested constructs exhibited a high degree of cellularity. Significant production of organized dentin and enamel-like tissues was observed in dTB-recell and nTB implants, but not in dTB or dTB-BMP implants. Micro-CT analyses of 6-mo implants showed the formation of organized, bioengineered teeth of comparable size to natural teeth. To our knowledge, these results are the first to describe the potential use of dTBs for functional whole tooth regeneration.

  10. Neurologic management following cardiac arrest.

    Science.gov (United States)

    Bircher, N G

    1989-10-01

    Optimal neurologic outcome after cardiac arrest requires careful attention to the details of both intracranial and extracranial homeostasis. A high index of suspicion regarding the potential causes and complications of cardiac arrest facilitates discovery and treatment of problems before they adversely affect neurologic outcome. The future is bright for resuscitation research: Our fundamental understanding of cerebral ischemia and its consequences has dramatically improved, and this knowledge can hopefully be transferred to clinical useful modes of therapy. However, the transition from a promising, therapeutically effective intervention in animals to the demonstration that treatment is effective following cardiac arrest in humans is an important and difficult step. The patient population is heterogeneous before the insult, the duration and severity of the insult are variable, and the effectiveness of cardiopulmonary resuscitation varies among institutions. Therefore, the only means of demonstrating clinical efficacy is the performance of a large clinical trial. The Resuscitation Research Center at the University of Pittsburgh has developed and coordinated a multicenter, multinational team of investigators who have completed one definitive trial of postarrest barbiturate therapy and are currently completing a similar trial using a calcium entry blocker. Despite the formidable obstacles posed by such comprehensive efforts, they provide the mechanism for determining whether the cost of a new treatment modality is justified by the likelihood of improved mortality or morbidity.

  11. Autogenous tooth transplantation for replacing a lost tooth: case reports

    OpenAIRE

    Kang, Ji-Youn; Chang, Hoon-Sang; Hwang,Yun-Chan; Hwang, In-Nam; Oh, Won-Mann; LEE, Bin-Na

    2013-01-01

    The autogenous tooth transplantation is an alternative treatment replacing a missing tooth when a suitable donor tooth is available. It is also a successful treatment option to save significant amount of time and cost comparing implants or conventional prosthetics. These cases, which required single tooth extraction due to deep caries and severe periodontal disease, could have good results by transplanting non-functional but sound donor tooth to the extraction site.

  12. The European Arrest Warrant

    Directory of Open Access Journals (Sweden)

    Minodora-Ioana Balan-Rusu

    2012-05-01

    Full Text Available In the paper it is generally examined the institution of the European arrest warrant according to the latest changes and additions through the adoption of a new European legislative act. The paper is a continuation of research in the area of judicial cooperation in criminal matters in the European Union. It may be useful to the judicial bodies with the responsibilities of issuing and executing a specific European arrest warrant and to academics and students in law schools. The research results, the essential contribution, the originality consist of the general examination of the institution, the critical remarks and proposals for amending and completing certain provisions insufficiently clear.

  13. Supernumerary Jawbone Tooth: Clinical Case

    OpenAIRE

    Rivas Gutiérrez, Jesús; Carlos Sánchez, María Dolores

    2016-01-01

    Introduction: supernumerary teeth are dental development anomalies, alsoknown as hyperdontia or extra teeth. Their prevalence ranges between 0.3% and 3.8%.Their morphology may be normal or dismorphic and are associated to the etiology ofocclusal alterations. It is important to make an early diagnostic through a radiographicalstudy. Case presentation:this article presents a clinical case of a supernumerary tooth thatcaused rotation and crowding of the anterior bottom teeth, which was addressed...

  14. Chromosome karyotype analysis in the study of clinical significance in embryo development arrest%染色体核型分析在胚胎停育中的临床意义的研究

    Institute of Scientific and Technical Information of China (English)

    张玉萍; 杨欣艳; 孙盛梅; 何春久; 张淑红; 朱金玲; 王长山

    2016-01-01

    目的 探讨胚胎停育的发病原因和胚胎停育染色体检测的临床意义.方法 获取107例胚胎停育患者的绒毛进行细胞培养,染色体制备与核型分析,结果 107例胚胎停育患者的胚胎绒毛组织,细胞培养失败6例,检出异常核型65例,染色体异常比率64.36%.结论 染色体异常是导致胚胎停育的重要因素.%Objective:To explore the etiology of embryo development arrest and clinical significance of embryo chromosome detection.Methods:Selected for 107 cases of patients with embryo development arrest chorionic villus,in cell culture,preparation of chromosome and karyotype analysis.Results:107 cases of patients with embryo development arrest villus tissue,cell culture failed to 6 cases,detected abnormal karyotype in 65 cases,chromosome abnormality rate was 64.36%.Conclusion:Chromosome abnormality is one of the important factors in embryo development arrest.

  15. Epithelial – Mesenchymal Interactions in Tooth Development and the Significant Role of Growth Factors and Genes with Emphasis on Mesenchyme – A Review

    Science.gov (United States)

    Kota, Kasim; Chakkarayan, Roopesh; Chakkarayan, Jithesh; Thodiyil, Abdul Kabeer Padinhare

    2016-01-01

    The recent advancements in medical research field mainly highlights the genetic and molecular aspects of various disease processes and related treatment options, in a specialized “custom-made” approach. The medical and dental field has made tremendous progress in providing even with the smallest insight into pathological entities, thus, making patient management more fruitful. But, short comings have occurred in dental treatments involving odontogenic lesions mainly due to poor understanding of the developmental cycle involved during early stages of developmental process. Multiple numbers of interactions take place during embryo formation and further proliferation of tissue. One such important step is the interaction between epithelium and mesenchyme which tantamount to functional requirements of an individual tooth. The role of extra cellular molecules and genes has to be studied in depth to assess the impact and significance attached to it as the synergistic function of various elements underlines the complex process of development. PMID:27790596

  16. Osteological associations with unique tooth development in manatees (Trichechidae, Sirenia): a detailed look at modern Trichechus and a review of the fossil record.

    Science.gov (United States)

    Beatty, Brian Lee; Vitkovski, Taisia; Lambert, Olivier; Macrini, Thomas E

    2012-09-01

    Modern manatees have a unique type of tooth development, continually forming identical new molars in the posterior end of each quadrant of their mouths, and then progressively moving teeth anteriorly, only to reabsorb roots and spit out worn crowns. This process is not only developmentally complex, but requires space in the oral cavity that imposes its own limitations on other uses of that space. To gain a clearer understanding of the anatomical constraints on the evolution of this unique developmental process, we identified the specialized craniodental features in modern Trichechus that permit this specialization using visual observation and CT. Furthermore, to better understand the evolution of these traits, we review the fossil record of trichechids for these traits, including CT analysis of the skull of Miosiren kocki, a possible early member of the family from the Early Miocene of Belgium.

  17. Tooth in oropharynx

    Directory of Open Access Journals (Sweden)

    D Nagarajappa

    2011-01-01

    Full Text Available The incidence of ectopic teeth has increased. In many cases, the etiology of ectopic teeth cannot be identified. Ectopic tooth in deciduous dentition period is very rare and information is limited about its causes and characteristics. The conditions commonly associated with an increased prevalence of ectopic teeth include cleft lip and palate, cleidocranial dysplasia, and Gardner syndrome. The diagnosis is made by the clinical and radiological examinations. The indication for extraction in ectopic teeth cases is in general determined by the presence of symptomatology, or by the need for preventing future complications. We present a case of an ectopic maxillary tooth in a 4 year-old boy. In addition, this report also addresses a young patient with a tooth in the oropharynx with the objective of non traumatic etiology, and such a clinical presentation is extremely rare. The authors believe the case presented here is the first documented case of an ectopic supernumerary tooth seen in the oropharynx.

  18. Tooth in oropharynx.

    Science.gov (United States)

    Nagarajappa, D; Manjunatha, Bs

    2011-09-01

    The incidence of ectopic teeth has increased. In many cases, the etiology of ectopic teeth cannot be identified. Ectopic tooth in deciduous dentition period is very rare and information is limited about its causes and characteristics. The conditions commonly associated with an increased prevalence of ectopic teeth include cleft lip and palate, cleidocranial dysplasia, and Gardner syndrome. The diagnosis is made by the clinical and radiological examinations. The indication for extraction in ectopic teeth cases is in general determined by the presence of symptomatology, or by the need for preventing future complications. We present a case of an ectopic maxillary tooth in a 4 year-old boy. In addition, this report also addresses a young patient with a tooth in the oropharynx with the objective of non traumatic etiology, and such a clinical presentation is extremely rare. The authors believe the case presented here is the first documented case of an ectopic supernumerary tooth seen in the oropharynx.

  19. Runway Arrested Landing Site (RALS)

    Data.gov (United States)

    Federal Laboratory Consortium — The Runway Arrested Landing Site includes an underground complex located on a Mod 2, Mod 3, and Mod 3+ arresting gear and are located under the runway and accurately...

  20. Frictional Effects on Gear Tooth Contact Analysis

    Directory of Open Access Journals (Sweden)

    Zheng Li

    2013-01-01

    Full Text Available The present paper concentrates on the investigations regarding the situations of frictional shear stress of gear teeth and the relevant frictional effects on bending stresses and transmission error in gear meshing. Sliding friction is one of the major reasons causing gear failure and vibration; the adequate consideration of frictional effects is essential for understanding gear contact behavior accurately. An analysis of tooth frictional effect on gear performance in spur gear is presented using finite element method. Nonlinear finite element model for gear tooth contact with rolling/sliding is then developed. The contact zones for multiple tooth pairs are identified and the associated integration situation is derived. The illustrated bending stress and transmission error results with static and dynamic boundary conditions indicate the significant effects due to the sliding friction between the surfaces of contacted gear teeth, and the friction effect can not be ignored. To understand the particular static and dynamic frictional effects on gear tooth contact analysis, some significant phenomena of gained results will also be discussed. The potentially significant contribution of tooth frictional shear stress is presented, particularly in the case of gear tooth contact analysis with both static and dynamic boundary conditions.

  1. Tooth enamel and enameloid in actinopterygian fish

    Institute of Scientific and Technical Information of China (English)

    I.SASAGAWA; M.ISHIYAMA; H.YOKOSUKA; M.MIKAMI; T.UCHIDA

    2009-01-01

    The morphological features of tooth enamel and enameloid in actinopterygian fish are reviewed to provide basic data concerning the biomineralization of teeth in lower vertebrates. Enameloid, which covers the tooth surface, is a unique well-mineralized tissue and usually has the same functions as mammalian tooth enamel. However, the development of enameloi is different from that of the enamel produced by dental epithelial cells. Enameloid is made by a combination of odontoblasts and dental epithelial cells. An organic matrix that contains collagen is provided by odontoblasts, and then dental epithelial cells dissolve the degenerate matrix and suooly inorganic ions during advanced crystal growth in enameloid. It is likely that enameloid is a good model for studying the growth of well-mineralized hard tissues in vertebrates. Some actinopterygian fish possess a collar enamel layer that is situated at the surface of the tooth shaft, indicating that the origin of tooth enamel is found in fish. Collar enamel is thought to be a precursor of mammalian enamel, although it is thin and not well mineralized in comparison with enameloid. In Lepisosteus and Polypterus, both of which are living actinopterygians,both enameloid and enamel are found in the same tooth. Therefore, they ace suitable materials for examining the developmental processes of enameloid and enamel and the relationship among them.

  2. Generation of growth arrested Leishmania amastigotes: a tool to develop live attenuated vaccine candidates against visceral leishmaniasis.

    Science.gov (United States)

    Selvapandiyan, Angamuthu; Dey, Ranadhir; Gannavaram, Sreenivas; Solanki, Sumit; Salotra, Poonam; Nakhasi, Hira L

    2014-06-30

    Visceral leishmaniasis (VL) is fatal if not treated and is prevalent widely in the tropical and sub-tropical regions of world. VL is caused by the protozoan parasite Leishmania donovani or Leishmania infantum. Although several second generation vaccines have been licensed to protect dogs against VL, there are no effective vaccines against human VL [1]. Since people cured of leishmaniasis develop lifelong protection, development of live attenuated Leishmania parasites as vaccines, which can have controlled infection, may be a close surrogate to leishmanization. This can be achieved by deletion of genes involved in the regulation of growth and/or virulence of the parasite. Such mutant parasites generally do not revert to virulence in animal models even under conditions of induced immune suppression due to complete deletion of the essential gene(s). In the Leishmania life cycle, the intracellular amastigote form is the virulent form and causes disease in the mammalian hosts. We developed centrin gene deleted L. donovani parasites that displayed attenuated growth only in the amastigote stage and were found safe and efficacious against virulent challenge in the experimental animal models. Thus, targeting genes differentially expressed in the amastigote stage would potentially attenuate only the amastigote stage and hence controlled infectivity may be effective in developing immunity. This review lays out the strategies for attenuation of the growth of the amastigote form of Leishmania for use as live vaccine against leishmaniasis, with a focus on visceral leishmaniasis.

  3. The embryo development arrest clinicalanalysis%孕早期胚胎停止发育的临床分析

    Institute of Scientific and Technical Information of China (English)

    卜春梅

    2013-01-01

    目的:探讨孕早期胚胎停止发育的原因。方法收集2011年8月至2013年8月来我院妇产科门诊就诊的2134例孕妇信息,经超声和临床检查确诊为孕早期胚胎停止发育的108例患者为研究对象。结果孕早期胚胎停止发育的常见病因包括染色体异常、子宫异常、免疫因素、内分泌失调、生殖器感染、环境因素等。导致孕早期胚胎停止发育的主要病因为子宫异常(25.93%)、环境因素(22.22%)、内分泌失调(21.30%)。结论导致孕早期胚胎停止发育的因素较多、早发现,早预防,早治疗是诊治的关键。%Objective to investigate the causes of early pregnancy to stop development of the embryo.Methods 2011 8 to august 2013 in our hospital obstetrics and gynecology clinic 2134 cases of pregnant women information by ultrasound and clinical examination diagnosed early embryos stop development of the 108 patients for the study.Results the early embryos stop development of common causes include chromosomal abnormalities, uterine abnormalities, immune factors, endocrine disorders, genital infections, and environmental factors. The result in the ifrst trimester embryo stops growing mainly because of abnormal uterine disease (25.93%), environmental factors (22.22%), endocrine disorders (21.30%).Conclusion embryo to stop the development of many factors result in the early stages of pregnancy, early detection, early prevention, early treatment is the key to the diagnosis and treatment.

  4. Arrested root formation of 4 second premolars: report of a patient.

    Science.gov (United States)

    Pinzon, Maria L; Gong, Siew-Ging

    2012-05-01

    The shape and size of tooth roots are genetically and phylogenetically predetermined. Clinical defects in root formation can manifest in the form of shortened roots caused by either root agenesis or root resorption. We report on a patient who came at age 7 years for space management. In the 2-year period after the initial visit, maxillary arch expansion was performed, followed by serial extractions of all 4 first premolars. A radiograph taken about 18 months after the serial extraction showed that although the crowns of all 4 second premolars had erupted fully into the arch, the roots were only about half of their normal length. With a family history of 1 sibling with a missing second premolar and the symmetrical distribution and pattern of the teeth in the 4 dental quadrants, we speculated that the arrested root development was due most likely to a genetic predisposition. Arrested root development is difficult to predict, but a potential warning sign is a family history of malformed or missing teeth. Proper, adequate, and accurate records continue to remain critical for both medical and legal purposes in the treatment of patients with potential problems in root agenesis.

  5. Biomaterial selection for tooth regeneration.

    Science.gov (United States)

    Yuan, Zhenglin; Nie, Hemin; Wang, Shuang; Lee, Chang Hun; Li, Ang; Fu, Susan Y; Zhou, Hong; Chen, Lili; Mao, Jeremy J

    2011-10-01

    Biomaterials are native or synthetic polymers that act as carriers for drug delivery or scaffolds for tissue regeneration. When implanted in vivo, biomaterials should be nontoxic and exert intended functions. For tooth regeneration, biomaterials have primarily served as a scaffold for (1) transplanted stem cells and/or (2) recruitment of endogenous stem cells. This article critically synthesizes our knowledge of biomaterial use in tooth regeneration, including the selection of native and/or synthetic polymers, three-dimensional scaffold fabrication, stem cell transplantation, and stem cell homing. A tooth is a complex biological organ. Tooth loss represents the most common organ failure. Tooth regeneration encompasses not only regrowth of an entire tooth as an organ, but also biological restoration of individual components of the tooth including enamel, dentin, cementum, or dental pulp. Regeneration of tooth root represents perhaps more near-term opportunities than the regeneration of the whole tooth. In the adult, a tooth owes its biological vitality, arguably more, to the root than the crown. Biomaterials are indispensible for the regeneration of tooth root, tooth crown, dental pulp, or an entire tooth.

  6. Arabidopsis CPR5 independently regulates seed germination and postgermination arrest of development through LOX pathway and ABA signaling.

    Directory of Open Access Journals (Sweden)

    Guilan Gao

    Full Text Available The phytohormone abscisic acid (ABA and the lipoxygenases (LOXs pathway play important roles in seed germination and seedling growth and development. Here, we reported on the functional characterization of Arabidopsis CPR5 in the ABA signaling and LOX pathways. The cpr5 mutant was hypersensitive to ABA in the seed germination, cotyledon greening and root growth, whereas transgenic plants overexpressing CPR5 were insensitive. Genetic analysis demonstrated that CPR5 gene may be located downstream of the ABI1 in the ABA signaling pathway. However, the cpr5 mutant showed an ABA independent drought-resistant phenotype. It was also found that the cpr5 mutant was hypersensitive to NDGA and NDGA treatment aggravated the ABA-induced delay in the seed germination and cotyledon greening. Taken together, these results suggest that the CPR5 plays a regulatory role in the regulation of seed germination and early seedling growth through ABA and LOX pathways independently.

  7. MeHg Developing Exposure Causes DNA Double-Strand Breaks and Elicits Cell Cycle Arrest in Spinal Cord Cells

    Science.gov (United States)

    Ferreira, Fabiana F.; Ammar, Dib; Bourckhardt, Gilian F.; Kobus-Bianchini, Karoline; Müller, Yara M. R.; Nazari, Evelise M.

    2015-01-01

    The neurotoxicity caused by methylmercury (MeHg) is well documented; however, the developmental neurotoxicity in spinal cord is still not fully understood. Here we investigated whether MeHg affects the spinal cord layers development. Chicken embryos at E3 were treated in ovo with 0.1 μg MeHg/50 μL saline solution and analyzed at E10. Thus, we performed immunostaining using anti-γ-H2A.X to recognize DNA double-strand breaks and antiphosphohistone H3, anti-p21, and anti-cyclin E to identify cells in proliferation and cell cycle proteins. Also, to identify neuronal cells, we used anti-NeuN and anti-βIII-tubulin antibodies. After the MeHg treatment, we observed the increase on γ-H2A.X in response to DNA damage. MeHg caused a decrease in the proliferating cells and in the thickness of spinal cord layers. Moreover, we verified that MeHg induced an increase in the number of p21-positive cells but did not change the cyclin E-positive cells. A significantly high number of TUNEL-positive cells indicating DNA fragmentation were observed in MeHg-treated embryos. Regarding the neuronal differentiation, MeHg induced a decrease in NeuN expression and did not change the expression of βIII-tubulin. These results showed that in ovo MeHg exposure alters spinal cord development by disturbing the cell proliferation and death, also interfering in early neuronal differentiation. PMID:26793240

  8. MeHg Developing Exposure Causes DNA Double-Strand Breaks and Elicits Cell Cycle Arrest in Spinal Cord Cells

    Directory of Open Access Journals (Sweden)

    Fabiana F. Ferreira

    2015-01-01

    Full Text Available The neurotoxicity caused by methylmercury (MeHg is well documented; however, the developmental neurotoxicity in spinal cord is still not fully understood. Here we investigated whether MeHg affects the spinal cord layers development. Chicken embryos at E3 were treated in ovo with 0.1 μg MeHg/50 μL saline solution and analyzed at E10. Thus, we performed immunostaining using anti-γ-H2A.X to recognize DNA double-strand breaks and antiphosphohistone H3, anti-p21, and anti-cyclin E to identify cells in proliferation and cell cycle proteins. Also, to identify neuronal cells, we used anti-NeuN and anti-βIII-tubulin antibodies. After the MeHg treatment, we observed the increase on γ-H2A.X in response to DNA damage. MeHg caused a decrease in the proliferating cells and in the thickness of spinal cord layers. Moreover, we verified that MeHg induced an increase in the number of p21-positive cells but did not change the cyclin E-positive cells. A significantly high number of TUNEL-positive cells indicating DNA fragmentation were observed in MeHg-treated embryos. Regarding the neuronal differentiation, MeHg induced a decrease in NeuN expression and did not change the expression of βIII-tubulin. These results showed that in ovo MeHg exposure alters spinal cord development by disturbing the cell proliferation and death, also interfering in early neuronal differentiation.

  9. Arrested development of the myxozoan parasite, Myxobolus cerebralis, in certain populations of mitochondrial 16S lineage III Tubifex tubifex

    Science.gov (United States)

    Baxa, D.V.; Kelley, G.O.; Mukkatira, K.S.; Beauchamp, K.A.; Rasmussen, C.; Hedrick, R.P.

    2008-01-01

    Laboratory populations of Tubifex tubifex from mitochondrial (mt)16S ribosomal DNA (rDNA) lineage III were generated from single cocoons of adult worms releasing the triactinomyxon stages (TAMs) of the myxozoan parasite, Myxobolus cerebralis. Subsequent worm populations from these cocoons, referred to as clonal lines, were tested for susceptibility to infection with the myxospore stages of M. cerebralis. Development and release of TAMs occurred in five clonal lines, while four clonal lines showed immature parasitic forms that were not expelled from the worm (non-TAM producers). Oligochaetes from TAM- and non-TAM-producing clonal lines were confirmed as lineage III based on mt16S rDNA and internal transcribed spacer region 1 (ITS1) sequences, but these genes did not differentiate these phenotypes. In contrast, random amplified polymorphic DNA analyses of genomic DNA demonstrated unique banding patterns that distinguished the phenotypes. Cohabitation of parasite-exposed TAM- and non-TAM-producing phenotypes showed an overall decrease in expected TAM production compared to the same exposure dose of the TAM-producing phenotype without cohabitation. These studies suggest that differences in susceptibility to parasite infection can occur in genetically similar T. tubifex populations, and their coexistence may affect overall M. cerebralis production, a factor that may influence the severity of whirling disease in wild trout populations. ?? 2007 Springer-Verlag.

  10. Tooth regeneration: current status.

    Science.gov (United States)

    Dadu, Shifali S

    2009-01-01

    Regeneration of a functional tooth has the potential to be a promising therapeutic strategy. Experiments have shown that with the use of principles of bioengineering along with adult stem cells, scaffold material, and signaling molecules, tooth regeneration is possible. Research work is in progress on creating a viable bioroot with all its support. A new culture needs to be created that can possibly provide all the nutrients to the stem cells. With the ongoing research, tissue engineering is likely to revolutionize dental health and well-being of people by regenerating teeth over the next decade.

  11. Tooth regeneration: Current status

    Directory of Open Access Journals (Sweden)

    Dadu Shifali

    2009-01-01

    Full Text Available Regeneration of a functional tooth has the potential to be a promising therapeutic strategy. Experiments have shown that with the use of principles of bioengineering along with adult stem cells, scaffold material, and signaling molecules, tooth regeneration is possible. Research work is in progress on creating a viable bioroot with all its support. A new culture needs to be created that can possibly provide all the nutrients to the stem cells. With the ongoing research, tissue engineering is likely to revolutionize dental health and well-being of people by regenerating teeth over the next decade.

  12. Regenerative Applications Using Tooth Derived Stem Cells in Other Than Tooth Regeneration: A Literature Review

    OpenAIRE

    2016-01-01

    Tooth derived stem cells or dental stem cells are categorized according to the location from which they are isolated and represent a promising source of cells for regenerative medicine. Originally, as one kind of mesenchymal stem cells, they are considered an alternative of bone marrow stromal cells. They share many commonalties but maintain differences. Considering their original function in development and the homeostasis of tooth structures, many applications of these cells in dentistry ha...

  13. Thermal development of Cephalonomia tarsalis (Hymenoptera: Bethylidae) parasitoid of the saw-toothed stored product beetles of the genus Oryzaephilus sp. (Coleoptera: Sylvanidae).

    Science.gov (United States)

    Eliopoulos, Panagiotis A; Kontodimas, Dimitrios C

    2016-02-01

    The effect of temperature on the development and survival of Cephalonomia tarsalis (Ashmead) (Hymenoptera: Bethylidae), larval ectoparasitoid of beetles of Oryzaephilus sp. (Coleoptera: Silvanidae) was studied in the laboratory. Durations of the development of the egg, larva and pupa were measured in eight constant temperatures (15, 17.5, 20, 25, 30, 32.5, 35 and 37.5°C) parasitizing larvae of the saw-toothed beetle Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae). The duration of development was decreased with temperature increase within the range 17.5-32.5°C. Survival was higher when immatures were exposed to medium temperatures (20-30°C) compared with those lived in a more extreme temperature regime (30°C). Wasps failed to complete their development at 15 and 37.5°C. Thermal parameters (upper, lower and optimum developmental threshold, thermal constant) were estimated by fitting the linear and a non-linear (Logan I) model to our data. Upper and lower developmental thresholds ranged between 35.1-37.0°C and 13.2-13.8°C, respectively. The optimum temperature for development was estimated between 33.6°C and 34.6°C. Tests for developmental rate isomorphy (DRI) showed that change in the average proportion of time spent in each developmental stage was marginally significant, proving that development of C. tarsalis is probably incompatible with DRI. However, this conclusion is questionable given that lower developmental thresholds did not differ significantly among various developmental stages (bootstrap test). Thermal constant for total development was calculated 212.4 degree-days. Our results are discussed not only on the basis of thermal biology, but also of improving the efficiency of C. tarsalis as biocontrol agent.

  14. Tooth Germ-Like Construct Transplantation for Whole-Tooth Regeneration: An In Vivo Study in the Miniature Pig.

    Science.gov (United States)

    Yang, Kai-Chiang; Kitamura, Yutaka; Wu, Chang-Chin; Chang, Hao-Hueng; Ling, Thai-Yen; Kuo, Tzong-Fu

    2016-04-01

    The purpose of this study was to demonstrate the feasibility of whole-tooth regeneration using a tooth germ-like construct. Dental pulp from upper incisors, canines, premolars, and molars were extracted from sexually mature miniature pigs. Pulp tissues were cultured and expanded in vitro to obtain dental pulp stem cells (DPSCs), and cells were differentiated into odontoblasts and osteoblasts. Epithelial cells were isolated from gingival epithelium. The epithelial cells, odontoblasts, and osteoblasts were seeded onto the surface, upper, and lower layers, respectively, of a bioactive scaffold. The lower first and second molar tooth germs were removed bilaterally and the layered cell/scaffold constructs were transplanted to the mandibular alveolar socket of a pig. At 13.5 months postimplantation, seven of eight pigs developed two teeth with crown, root, and pulp structures. Enamel-like tissues, dentin, cementum, odontoblasts, and periodontal tissues were found upon histological inspection. The regenerated tooth expressed dentin matrix protein-1 and osteopontin. All pigs had regenerated molar teeth regardless of the original tooth used to procure the DPSCs. Pigs that had tooth germs removed or who received empty scaffolds did not develop teeth. Although periodontal ligaments were generated, ankylosis was found in some animals. This study revealed that implantation of a tooth germ-like structure generated a complete tooth with a high success rate. The implant location may influence the morphology of the regenerated tooth.

  15. Histology of tooth attachment tissues and plicidentine in Varanus (Reptilia: Squamata), and a discussion of the evolution of amniote tooth attachment.

    Science.gov (United States)

    Maxwell, Erin E; Caldwell, Michael W; Lamoureux, Denis O; Budney, Lisa A

    2011-10-01

    Few recent studies have examined the histological basis for tooth attachment in squamates. In the past few years, a surge of interest in this topic has led to the intriguing suggestion that the major tissues derived from the tooth germ (enamel, dentine, cementum and alveolar bone), are conservative and are present in all amniotes. In this study, we describe the histology and development of the tooth attachment complex in Varanus rudicollis, the rough-neck monitor. We provide the first published evidence for the role of cementum and alveolar bone in tooth attachment in varanoid lizards. In Varanus, cementum is deposited on the external surface of the tooth root as well as at the base of the tooth, where it plays a role in the attachment of the tooth to the jawbone. Alveolar bone is also involved in tooth ankylosis. Our results support the hypothesis that the major tooth germ tissues are found in all amniotes. We provide insights into the structure and development of plicidentine, defined as infolding of the dentine around the tooth base. This feature is unique to varanoids among extant tetrapods and is the third tissue implicated in tooth attachment in Varanus. Plicidentine develops asymmetrically along the labial-lingual axis of a tooth. Varanus is characterized by the presence of both primary and higher-order lamellae, which anastomose to form a honeycomb-like surface that then interacts with the more basal attachment tissues.

  16. Impact of gin saw tooth design on fiber and textile processing quality

    Science.gov (United States)

    Toothed gin saws have been used to separate cotton fiber from the seed for over 200 years. There have been many saw tooth designs developed over the years. Most of these designs were developed by trial and error. A complete and scientific analysis of tooth design has never been done. It is not k...

  17. 年轻恒牙外伤固定方法的研究进展%Developments on fixation techniques for immature permanent tooth

    Institute of Scientific and Technical Information of China (English)

    何怡; 邹静; 杨燃

    2013-01-01

      牙外伤是儿童口腔科的常见病。年轻恒牙由于牙根尚未发育完成,外伤时容易发生移位,正确的固定技术是保证治疗成功率的关键。近年来以粘接技术为基础的弹性固定已经逐渐取代了传统的结扎坚固固定。本文就各种牙外伤固定治疗方法及其临床效果作一综述。%Traumatic injury of teeth is a common disease in clinic of pediatric dentistry, which often results in the dislocation of young permanent tooth for its immature root. Correct fix technique is the key to insure the successful rate of root development of traumatic young permanent teeth. In recent years, elastic fixations which focus on adhesive technique have gradually replaced the traditional ligation strong fixation. The objective of this article is to review the various treatment methods of the traumatized teeth and its clinical results.

  18. Cardiac Arrest-Induced Global Brain Hypoxia-Ischemia during Development Affects Spontaneous Activity Organization in Rat Sensory and Motor Thalamocortical Circuits during Adulthood.

    Science.gov (United States)

    Shoykhet, Michael; Middleton, Jason W

    2016-01-01

    Normal maturation of sensory information processing in the cortex requires patterned synaptic activity during developmentally regulated critical periods. During early development, spontaneous synaptic activity establishes required patterns of synaptic input, and during later development it influences patterns of sensory experience-dependent neuronal firing. Thalamocortical neurons occupy a critical position in regulating the flow of patterned sensory information from the periphery to the cortex. Abnormal thalamocortical inputs may permanently affect the organization and function of cortical neuronal circuits, especially if they occur during a critical developmental window. We examined the effect of cardiac arrest (CA)-associated global brain hypoxia-ischemia in developing rats on spontaneous and evoked firing of somatosensory thalamocortical neurons and on large-scale correlations in the motor thalamocortical circuit. The mean spontaneous and sensory-evoked firing rate activity and variability were higher in CA injured rats. Furthermore, spontaneous and sensory-evoked activity and variability were correlated in uninjured rats, but not correlated in neurons from CA rats. Abnormal activity patterns of ventroposterior medial nucleus (VPm) neurons persisted into adulthood. Additionally, we found that neurons in the entopeduncular nucleus (EPN) in the basal ganglia had lower firing rates yet had higher variability and higher levels of burst firing after injury. Correlated levels of power in local field potentials (LFPs) between the EPN and the motor cortex (MCx) were also disrupted by injury. Our findings indicate that hypoxic-ischemic injury during development leads to abnormal spontaneous and sensory stimulus-evoked input patterns from thalamus to cortex. Abnormal thalamic inputs likely permanently and detrimentally affect the organization of cortical circuitry and processing of sensory information. Hypoxic-ischemic injury also leads to abnormal single neuron and

  19. Detecting Tooth Damage in Geared Drive Trains

    Science.gov (United States)

    Nachtsheim, Philip R.

    1997-01-01

    This paper describes a method that was developed to detect gear tooth damage that does not require a priori knowledge of the frequency characteristic of the fault. The basic idea of the method is that a few damaged teeth will cause transient load fluctuations unlike the normal tooth load fluctuations. The method attempts to measure the energy in the lower side bands of the modulated signal caused by the transient load fluctuations. The method monitors the energy in the frequency interval which excludes the frequency of the lowest dominant normal tooth load fluctuation and all frequencies above it. The method reacted significantly to the tooth fracture damage results documented in the Lewis data sets which were obtained from tests of the OH-58A transmission and tests of high contact ratio spiral bevel gears. The method detected gear tooth fractures in all four of the high contact ratio spiral bevel gear runs. Published results indicate other detection methods were only able to detect faults for three out of four runs.

  20. Analysis of the Permanent Tooth Eruption and Contraction of Dental Caries Based on Physical Development in School Children

    OpenAIRE

    相澤 徳久; 結城 昌子; アイザワ ノリヒサ; ユキ マサコ; Aizawa, Norihisa; Masako YUKI

    2006-01-01

    We performed a cohort study on the physical development, eruption of permanent teeth, and contraction of dental caries in school children. To establish criteria for the effective maintenance of dental hygiene, we analyzed the relationship between the eruption of permanent teeth and contraction of dental caries based on the physical development. The subjects were 373 elementary school children in Koriyama City, consisting of 215 boys and 158 girls, who were examined from their first to sixth g...

  1. Common developmental pathways link tooth shape to regeneration.

    Science.gov (United States)

    Fraser, Gareth J; Bloomquist, Ryan F; Streelman, J Todd

    2013-05-15

    In many non-mammalian vertebrates, adult dentitions result from cyclical rounds of tooth regeneration wherein simple unicuspid teeth are replaced by more complex forms. Therefore and by contrast to mammalian models, the numerical majority of vertebrate teeth develop shape during the process of replacement. Here, we exploit the dental diversity of Lake Malawi cichlid fishes to ask how vertebrates generally replace their dentition and in turn how this process acts to influence resulting tooth morphologies. First, we used immunohistochemistry to chart organogenesis of continually replacing cichlid teeth and discovered an epithelial down-growth that initiates the replacement cycle via a labial proliferation bias. Next, we identified sets of co-expressed genes from common pathways active during de novo, lifelong tooth replacement and tooth morphogenesis. Of note, we found two distinct epithelial cell populations, expressing markers of dental competence and cell potency, which may be responsible for tooth regeneration. Related gene sets were simultaneously active in putative signaling centers associated with the differentiation of replacement teeth with complex shapes. Finally, we manipulated targeted pathways (BMP, FGF, Hh, Notch, Wnt/β-catenin) in vivo with small molecules and demonstrated dose-dependent effects on both tooth replacement and tooth shape. Our data suggest that the processes of tooth regeneration and tooth shape morphogenesis are integrated via a common set of molecular signals. This linkage has subsequently been lost or decoupled in mammalian dentitions where complex tooth shapes develop in first generation dentitions that lack the capacity for lifelong replacement. Our dissection of the molecular mechanics of vertebrate tooth replacement coupled to complex shape pinpoints aspects of odontogenesis that might be re-evolved in the lab to solve problems in regenerative dentistry.

  2. Analysis of the soluble human tooth proteome and its ability to induce dentin/tooth regeneration.

    Science.gov (United States)

    Chun, So Young; Lee, Hyo Jung; Choi, Young Ae; Kim, Kyung Min; Baek, Sang Heum; Park, Hyo Sang; Kim, Jae-Young; Ahn, Jung-Mo; Cho, Je-Yeol; Cho, Dong-Woo; Shin, Hong-In; Park, Eui Kyun

    2011-01-01

    While the soluble proteins of human teeth consist of various extracellular matrix and bioactive proteins, they have not yet been characterized fully. Moreover, the role they play in tooth regeneration is not clear. Analysis of the soluble proteins in human teeth by liquid chromatography-mass spectrometry revealed 147 different ethylenediaminetetraacetic acid-soluble tooth proteins (ESTPs). Of these, 29 had not been shown previously to be present in human teeth. To determine their effect on the in vitro responses of dental pulp stem cells (DPSCs), DPSCs were cultured in ESTP-coated culture plates and three-dimensional scaffolds. The ESTPs significantly enhanced DPSC odontoblast differentiation and mineralization in vitro, but had only partial effect on bone marrow stem cells or adipose tissue stem cells. To test the effect of ESTPs on in vivo dentin and tooth formation, mouse embryonic tooth-forming primordia and xenogenic murine apical bud epithelium/human DPSC composites were treated with ESTPs before implantation under the renal capsule of ICR mice. ESTP treatment promoted the formation of morphologically normal teeth by the tooth-forming primordium regions and enhanced the development of a regular and large dentin structure by the composites. These observations suggest that human ESTPs contain dentinogenic proteins and can promote dentin and tooth formation.

  3. [Ectopic molar tooth in the maxillary sinus].

    Science.gov (United States)

    Altun, Hüseyin; Teker, Ayşenur Meriç; Ceran, Murat; Gedikli, Orhan

    2007-01-01

    The development of intranasal ectopic teeth is rare. Although they are more commonly seen in the palate and maxillary sinus, they can also be found in the mandibular condyle, coronoid process, and nasal cavity. A 30-year-old male patient presented with a complaint of headache. Computed tomography of the paranasal sinuses showed a bony mass in the right maxillary sinus wall, 1 cm in size. He did not have any history of maxillofacial trauma or operation. The mass was removed via a Caldwell-Luc procedure. It looked like a tooth. Histopathologic diagnosis was made as ectopic molar tooth. The patient was asymptomatic two weeks after the operation.

  4. Drinking coffee may help accelerate orthodontic tooth movement

    Directory of Open Access Journals (Sweden)

    Jianru Yi

    2012-01-01

    Full Text Available Introduction: Developing new methods to enhance orthodontic tooth movement and shorten the duration of treatment has always been desired. However, to date, no therapies have been widely used in clinics. Recent studies and feedback information from patients have shown that drinking coffee may accelerate orthodontic tooth movement. The Hypothesis: Drinking coffee, as a daily habit of many people, can be an effective accelerator of tooth movement with little side effect for caffeine can break the calcium balance in bone tissue and directly inhibit the development of osteoblasts, leading to temporary decreased bone mineral density and consequently inducing faster orthodontic tooth movement. Evaluation of the Hypothesis: Much effort has been made to explore therapies to shorten orthodontic treatment period with limited success. Daily coffee consumption may be a promising approach to enhance orthodontic tooth movement for its reversible effect on bone mineral density and calcium balance.

  5. Saw-tooth cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Karatza Ageliki A

    2009-12-01

    Full Text Available Abstract We present an unusual case of cardiomyopathy in a two month old male infant with a grade-I systolic murmur. Echocardiographic examination disclosed left ventricular (LV, dysplasia with saw-tooth like inwards myocardial projections extending from the lateral walls towards the LV cavity. There was mild LV systolic dysfunction with apical hypokinesia. Cardiovascular magnetic resonance demonstrated in detail these cross bridging muscular projections originating from the inferior interventricular septum and lateral LV wall, along with areas of hypokinesis at the LV septum and apex in a noncoronary distribution, without any late gadolinium enhancement. We have termed this condition saw-tooth cardiomyopathy because of the very characteristic appearance.

  6. 牙仙女%The Tooth Fairy

    Institute of Scientific and Technical Information of China (English)

    李世荣

    2009-01-01

    @@ The American children’s ritual of hiding a lost tooth under a pillow stems from an old German tradition of placing a lost tooth in a mouse or rat hole SO that when a new tooth grew in,it would possess the strong dental qualities of a rodent’S tooth.In America the “tooth rat”was replaced by the“tooth fairy”,who would compensate the child with money for surrendering a tooth to her.

  7. Solving tooth sensitivity.

    Science.gov (United States)

    Miller, Michael B

    2010-01-01

    Solving tooth sensitivity requires both you and the patients to be resilient and to understand that if one approach doesn't work, you can try another one that is non-invasive or, at worst, minimally invasive. Much like the clinician who posted the original question, I strongly believe that it is our responsibility to convince patients that jumping to a radical solution could be totally unnecessary--and expensive-- and still might not solve the problem.

  8. Tooth in oropharynx

    OpenAIRE

    Nagarajappa, D; B S Manjunatha

    2011-01-01

    The incidence of ectopic teeth has increased. In many cases, the etiology of ectopic teeth cannot be identified. Ectopic tooth in deciduous dentition period is very rare and information is limited about its causes and characteristics. The conditions commonly associated with an increased prevalence of ectopic teeth include cleft lip and palate, cleidocranial dysplasia, and Gardner syndrome. The diagnosis is made by the clinical and radiological examinations. The indication for extraction in ec...

  9. The influence of electrospun fibre scaffold orientation and nano-hydroxyapatite content on the development of tooth bud stem cells in vitro

    NARCIS (Netherlands)

    Manen, E.H. van; Zhang, W.; Walboomers, X.F.; Vazquez, B.; Yang, F.; Ji, W.; Yu, N.; Spear, D.J.; Jansen, J.A.; Yelick, P.C.

    2014-01-01

    In stem cell-based dental tissue engineering, the goal is to create tooth-like structures using scaffold materials to guide the dental stem cells. In this study, the effect of fiber alignment and hydroxyapatite content in biodegradable electrospun PLGA scaffolds have been investigated. Fiber orienta

  10. Application of spontaneously immortalized odontoblast cells in tooth regeneration.

    Science.gov (United States)

    Arany, Szilvia; Kawagoe, Masami; Sugiyama, Toshihiro

    2009-03-27

    Here, we report on the first attempt to bioengineer tooth using a spontaneously immortalized mesenchymal cell line. To assess the odontogenic potential of this cell line, odontoblast-lineage cells (OLC) were re-associated with competent dental epithelium isolated from E14.5 mice. A novel three-dimensional organ germ culture method was applied to nurture the constructs in vitro. Additionally, recombinants were transplanted under the kidney capsule in host animals for 2 weeks. Transplants developed into tooth tissues in one-third of the cases. OLC-derived GFP-positive cells could be identified in mineralizing tooth germs by immunohistochemistry. OLCs were capable of intercellular and cell-matrix communication, thus they eventually differentiated into functional odontoblasts. In summary, we managed to utilize OLCs for dental mesenchyme substitution in tooth regeneration experiments. Therefore, our spontaneously transformed cell line proved its potential for future complex, tooth developmental and bioengineering studies.

  11. Performance of metal oxide gapless surge arresters for HVDC systems

    Energy Technology Data Exchange (ETDEWEB)

    Diseko, N.L.

    1990-09-01

    An examination of the electrical stresses which may be imposed upon metal oxide surge arresters in a dc converter station is undertaken by means of simulation of the dc system and associated ac systems in the time domain using a digital computer program. Detailed models of a dc link are developed for temporary overvoltage stresses and steep front stresses. The most critical stresses for each type of dc station arrester due to converter faults and converter malfunctions are identified. The energy stresses were generally determined to be dependent on the converter control and protection strategies adopted during the faults. The arrester energy stresses for faults on both the line side and valve side busses of the converter transformer were determined to be sensitive to the instant of fault application and the duration of the fault. The arrester stresses for ac bus faults were analyzed in detail to determine their statistical distribution relative to the point on wave at which the fault occurred in each affected phase, and to the instant of fault clearance in each phase. Generally, the highest stresses occur for sequential fault occurrence in the phases compared with simultaneous faults. The studies indicate that the stresses in the arresters in a dc pile experiencing the worst duty depend on the number of arresters represented. Modelling only one arrester of a series-connected group does not provide correct results when the fault condition imposes duty on more than one of the arresters in the group. The study also indicates that the highest stresses do not necessarily occur in the single arrester connected across the valve with the highest prospective overvoltage. Hence the capability to represent all valve arresters within one pole is necessary when determining the most onerous stresses. 11 refs., 79 figs., 28 tabs.

  12. [Arrest of maturation in spermatogenesis].

    Science.gov (United States)

    Francavilla, S; Bellocci, M; Martini, M; Bruno, B; Moscardelli, S; Fabbrini, A; Properzi, G

    1982-07-30

    The ultrastructural aspects of the germinal epithelium of 10 infertile men affected by maturative arrest of spermatogenesis were studied. We noted an increased number of malformed germinal cells. Marginal nuclear vescicles were present in spermatogonia of patients affected by spermatogonial arrest. The few spermatid present in the germinal epithelium of the patients affected by a spermatidic arrest presented changes of the nuclear condensation, the acrosome, and the tail. The Sertoli cells presented an immature aspect of the nucleus and changes of the "mantle". A possible correlation between the Sertoli cells changes and the altered spermatogenesis was proposed.

  13. Autogenous tooth transplantation: an alternative to replace extracted tooth

    Directory of Open Access Journals (Sweden)

    David B. Kamadjaja

    2015-09-01

    Full Text Available Background: The gold standard treatment to replace missing tooth is dental implants, however, in certain cases, such as in young patients its placement is contraindicated. Autogenous tooth transplantation, which has been widely done in Scandinavian countries for many years, may become a good alternative to overcome this problem. Purpose: This article attempted to provide information about the indication, treatment planning, surgical technique and the successful result of autogenous tooth transplantation. Case: A fifteen year old male patient presented with large caries and periapical disease of his lower left first molar, which was partially erupted and the roots was not fully formed in radiograph. Case management: Autogenous tooth transplantation procedure was performed consisting of extraction of #36, odontectomy of #38 followed by its implantation to socket #36 and fixation of the transplanted tooth to the adjacent teeth. Post operative evaluation was done on regular basis within 18 months period. There was no complaint, the tooth was clinically stable and no evidence of periodontal problem. Serial radiographs showed healing of alveolar bone and periodontal tissue, and the complete root formation was evident by 18 months post operatively. Conclusion: Autogenous tooth transplantation is a potential alternative to replace extracted tooth. Provided that the case be properly planned and operation carefully performed, successful result of this treatment can be achieved.

  14. Enhanced Prediction of Gear Tooth Surface Fatigue Life Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Sentient will develop an enhanced prediction of gear tooth surface fatigue life with rigorous analysis of the tribological phenomena that contribute to pitting...

  15. Functional tooth regeneration using a bioengineered tooth unit as a mature organ replacement regenerative therapy.

    Science.gov (United States)

    Oshima, Masamitsu; Mizuno, Mitsumasa; Imamura, Aya; Ogawa, Miho; Yasukawa, Masato; Yamazaki, Hiromichi; Morita, Ritsuko; Ikeda, Etsuko; Nakao, Kazuhisa; Takano-Yamamoto, Teruko; Kasugai, Shohei; Saito, Masahiro; Tsuji, Takashi

    2011-01-01

    Donor organ transplantation is currently an essential therapeutic approach to the replacement of a dysfunctional organ as a result of disease, injury or aging in vivo. Recent progress in the area of regenerative therapy has the potential to lead to bioengineered mature organ replacement in the future. In this proof of concept study, we here report a further development in this regard in which a bioengineered tooth unit comprising mature tooth, periodontal ligament and alveolar bone, was successfully transplanted into a properly-sized bony hole in the alveolar bone through bone integration by recipient bone remodeling in a murine transplantation model system. The bioengineered tooth unit restored enough the alveolar bone in a vertical direction into an extensive bone defect of murine lower jaw. Engrafted bioengineered tooth displayed physiological tooth functions such as mastication, periodontal ligament function for bone remodeling and responsiveness to noxious stimulations. This study thus represents a substantial advance and demonstrates the real potential for bioengineered mature organ replacement as a next generation regenerative therapy.

  16. Exceptionally prolonged tooth formation in elasmosaurid plesiosaurians

    Science.gov (United States)

    Kear, Benjamin P.; Larsson, Dennis; Lindgren, Johan; Kundrát, Martin

    2017-01-01

    Elasmosaurid plesiosaurians were globally prolific marine reptiles that dominated the Mesozoic seas for over 70 million years. Their iconic body-plan incorporated an exceedingly long neck and small skull equipped with prominent intermeshing ‘fangs’. How this bizarre dental apparatus was employed in feeding is uncertain, but fossilized gut contents indicate a diverse diet of small pelagic vertebrates, cephalopods and epifaunal benthos. Here we report the first plesiosaurian tooth formation rates as a mechanism for servicing the functional dentition. Multiple dentine thin sections were taken through isolated elasmosaurid teeth from the Upper Cretaceous of Sweden. These specimens revealed an average of 950 daily incremental lines of von Ebner, and infer a remarkably protracted tooth formation cycle of about 2–3 years–other polyphyodont amniotes normally take ~1–2 years to form their teeth. Such delayed odontogenesis might reflect differences in crown length and function within an originally uneven tooth array. Indeed, slower replacement periodicity has been found to distinguish larger caniniform teeth in macrophagous pliosaurid plesiosaurians. However, the archetypal sauropterygian dental replacement system likely also imposed constraints via segregation of the developing tooth germs within discrete bony crypts; these partly resorbed to allow maturation of the replacement teeth within the primary alveoli after displacement of the functional crowns. Prolonged dental formation has otherwise been linked to tooth robustness and adaption for vigorous food processing. Conversely, elasmosaurids possessed narrow crowns with an elongate profile that denotes structural fragility. Their apparent predilection for easily subdued prey could thus have minimized this potential for damage, and was perhaps coupled with selective feeding strategies that ecologically optimized elasmosaurids towards more delicate middle trophic level aquatic predation. PMID:28241059

  17. Partial tooth gear bearings

    Science.gov (United States)

    Vranish, John M. (Inventor)

    2010-01-01

    A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.

  18. A windowing and mapping strategy for gear tooth fault detection of a planetary gearbox

    Science.gov (United States)

    Liang, Xihui; Zuo, Ming J.; Liu, Libin

    2016-12-01

    When there is a single cracked tooth in a planet gear, the cracked tooth is enmeshed for very short time duration in comparison to the total time of a full revolution of the planet gear. The fault symptom generated by the single cracked tooth may be very weak. This study aims to develop a windowing and mapping strategy to interpret the vibration signal of a planetary gear at the tooth level. The fault symptoms generated by a single cracked tooth of the planet gear of interest can be extracted. The health condition of the planet gear can be assessed by comparing the differences among the signals of all teeth of the planet gear. The proposed windowing and mapping strategy is tested with both simulated vibration signals and experimental vibration signals. The tooth signals can be successfully decomposed and a single tooth fault on a planet gear can be effectively detected.

  19. Making a tooth: growth factors, transcription factors, and stem cells

    Institute of Scientific and Technical Information of China (English)

    Yah Ding ZHANG; Zhi CHEN; Yi Qiang SONG; Chao LIU; Yi Ping CHEN

    2005-01-01

    Mammalian tooth development is largely dependent on sequential and reciprocal epithelial-mesenchymal interactions.These processes involve a series of inductive and permissive interactions that result in the determination, differentiation,and organization of odontogenic tissues. Multiple signaling molecules, including BMPs, FGFs, Shh, and Wnt proteins,have been implicated in mediating these tissue interactions. Transcription factors participate in epithelial-mesenchymal interactions via linking the signaling loops between tissue layers by responding to inductive signals and regulating the expression of other signaling molecules. Adult stem cells are highly plastic and multipotent. These cells including dental pulp stem cells and bone marrow stromal cells could be reprogrammed into odontogenic fate and participated in tooth formation. Recent progress in the studies of molecular basis of tooth development, adult stem cell biology, and regeneration will provide fundamental knowledge for the realization of human tooth regeneration in the near future.

  20. Analysis of Crack Arrest Toughness.

    Science.gov (United States)

    1988-01-15

    vload(m) vp tn(m) Vertical Source Load (kN) on wedge HY80 Finite Element 0.0122 0.0099 3.81x10 -4 144 Steel Calculations Experiment 0.0122 --- 3.74x10-4...curve, are bona fide measures of the fracture arrest capability of tough ductile steels . The second is that the J-values represent the crack driving...fibrous mode of crack extension. (b) A new test method for studying fast fracture and arrest in tough steels . (c) Measurements of fast fracture and crack

  1. Atypical Odontalgia (Phantom Tooth Pain)

    Science.gov (United States)

    ... atypical facial pain, phantom tooth pain, or neuropathic orofacial pain, is characterized by chronic pain in a ... such as a specialist in oral medicine or orofacial pain. The information contained in this monograph is ...

  2. Biomaterial Selection for Tooth Regeneration

    OpenAIRE

    2011-01-01

    Biomaterials are native or synthetic polymers that act as carriers for drug delivery or scaffolds for tissue regeneration. When implanted in vivo, biomaterials should be nontoxic and exert intended functions. For tooth regeneration, biomaterials have primarily served as a scaffold for (1) transplanted stem cells and/or (2) recruitment of endogenous stem cells. This article critically synthesizes our knowledge of biomaterial use in tooth regeneration, including the selection of native and/or s...

  3. Comparative development of mouse tooth germs transplanted in subrenal capsule and oral submucosa%小鼠牙胚在肾包膜及口腔黏膜环境下成牙能力的比较研究

    Institute of Scientific and Technical Information of China (English)

    何颖; 刘朋飞; 刘晓; 朴正根; 蔡景蕾

    2015-01-01

    germs and for exploring the ideal environment for tooth regeneration .METHODS: Two groups were set up .Group A was transplanted with the mouse embronic day ( ED) 14.5 first mandibular molar tooth germs into the subrenal capsule , while group B was transplanted with the ED 14.5 first mandibular molar tooth germs into the oral submucosa.After 3 weeks and 4 weeks, the host mice were sacrificed, and the transplanted explants were evaluated with morphologic observation , histological structures , hardness and elastictic modulus tests , and chemical compositions .RE-SULTS:(1) The explants isolated from both environments showed the tooth-like structures, but as to the group B, the crown was smaller, and the shape of the cusps was not significant .(2) HE staining showed that the dentin and enamel in group A were thicker than those in group B in which the ameloblasts and odontoblasts were differentiated not very well .(3) In the test of enamel hardness , only the hardness of 4 weeks in group B was lower than normal mouse tooth .In the test of enamel modulus , the elastic modulus of enamel in 3 weeks of group A was slightly lower than normal mouse tooth , but the difference was not significant .The elastic modulus of enamel in 4 weeks of group A and group B was significantly lower than normal mouse tooth and 3 weeks of group B .The hardness and elastic modulus of dentin in 3 groups was not significant . (4) Raman spectroscopy showed 2 groups grew in harmony in general , they all had the largest peak in the point of 961 cm-1 , but the 3 weeks of group B had an obvious peak in the point of 2 947 cm-1 .CONCLUSION:For the development of ED14.5 tooth germs, we obtain almost the whole tooth in subrenal capsule transplantation after 3 or 4 weeks.The buccal submucosa environment still has a certain influence on the tooth germ development , although there are some differences about the tooth development between this environment and subrenal capsule environment .

  4. Exposure to the Contraceptive Progestin, Gestodene, Alters Reproductive Behavior, Arrests Egg Deposition, and Masculinizes Development in the Fathead Minnow (Pimephales promelas).

    Science.gov (United States)

    Frankel, Tyler E; Meyer, Michael T; Kolpin, Dana W; Gillis, Amanda B; Alvarez, David A; Orlando, Edward F

    2016-06-07

    Endogenous progestogens and pharmaceutical progestins enter the environment through wastewater treatment plant effluent and agricultural field runoff. Lab studies demonstrate strong, negative exposure effects of these chemicals on aquatic vertebrate reproduction. Behavior can be a sensitive, early indicator of exposure to environmental contaminants associated with altered reproduction yet is rarely examined in ecotoxicology studies. Gestodene is a human contraceptive progestin and a potent activator of fish androgen receptors. Our objective was to test the effects of gestodene on reproductive behavior and associated egg deposition in the fathead minnow. After only 1 day, males exposed to ng/L of gestodene were more aggressive and less interested in courtship and mating, and exposed females displayed less female courtship behavior. Interestingly, 25% of the gestodene tanks contained a female that drove the male out of the breeding tile and displayed male-typical courtship behaviors toward the other female. Gestodene decreased or arrested egg deposition with no observed gonadal histopathology. Together, these results suggest that effects on egg deposition are primarily due to altered reproductive behavior. The mechanisms by which gestodene disrupts behavior are unknown. Nonetheless, the rapid and profound alterations of the reproductive biology of gestodene-exposed fish suggest that wild populations could be similarly affected.

  5. Exposure to the contraceptive progestin, gestodene, alters reproductive behavior, arrests egg deposition, and masculinizes development in the fathead minnow (Pimephales promelas)

    Science.gov (United States)

    Frankel, Tyler E.; Meyer, Michael T.; Kolpin, Dana W.; Gillis, Amanda B.; Alvarez, David A.; Orlando, Edward F.

    2016-01-01

    Endogenous progestogens and pharmaceutical progestins enter the environment through wastewater treatment plant effluent and agricultural field runoff. Lab studies demonstrate strong, negative exposure effects of these chemicals on aquatic vertebrate reproduction. Behavior can be a sensitive, early indicator of exposure to environmental contaminants associated with altered reproduction yet is rarely examined in ecotoxicology studies. Gestodene is a human contraceptive progestin and a potent activator of fish androgen receptors. Our objective was to test the effects of gestodene on reproductive behavior and associated egg deposition in the fathead minnow. After only 1 day, males exposed to ng/L of gestodene were more aggressive and less interested in courtship and mating, and exposed females displayed less female courtship behavior. Interestingly, 25% of the gestodene tanks contained a female that drove the male out of the breeding tile and displayed male-typical courtship behaviors toward the other female. Gestodene decreased or arrested egg deposition with no observed gonadal histopathology. Together, these results suggest that effects on egg deposition are primarily due to altered reproductive behavior. The mechanisms by which gestodene disrupts behavior are unknown. Nonetheless, the rapid and profound alterations of the reproductive biology of gestodene-exposed fish suggest that wild populations could be similarly affected.

  6. Tooth anomalies associated with failure of eruption of first and second permanent molars.

    Science.gov (United States)

    Baccetti, T

    2000-12-01

    The occurrence of tooth anomalies in association with failure of the first and second molars to erupt was assessed in a sample of 1520 nonsyndromic subjects with uncrowded dental arches (mean age, 14 years 4 months) and compared with the prevalence rate calculated in a matched control group of 1000 subjects. The tooth anomalies examined included infraocclusion of deciduous molars, palatal displacement of maxillary canines, rotation of maxillary lateral incisors, aplasia of second premolars, and small size of maxillary lateral incisors. Associations among arrested eruption of first and second permanent molars and anomalies in tooth eruption and position (infraoccluded deciduous molars, palatally displaced canines, rotated maxillary lateral incisors) were highly significant (P position, most likely under genetic influence.

  7. 转录因子FoxO3a在小鼠牙胚发育过程中的表达%Expression of Transcription Factor FoxO3a in the Development of Mouse Tooth Germ

    Institute of Scientific and Technical Information of China (English)

    王云虹; 慈浩粟; 杨勇

    2013-01-01

    Objective To explore role of the expression and distribution of transcription factor FoxO 3 a in the development of mouse tooth germ .Methods Three new born KunMing mice and three 3 days old KunMing mice were chosen ,and their mandibles were dissected ,fixed overnight in the 10%neutral formaldehyde solution .Tissue sam-ples of mouse tooth germ were made ,embedded in paraffin ,and prepared to be close to 5μm serial sections .The expres-sion and distribution of transcription factor FoxO 3a in the development of mouse tooth germ at different stages were ob-served by immunohistochemistry methods and analysis was took .Results There were differences among distribution of FoxO3 a in the development of mouse tooth germ at different stages Negative expression of odontoblast was found in new born nice,and the positive expression was in 3 days mice.Conclusion FoxO3a may be involved in the formation and mineralization of the dentin ,according to expression of FoxO3a in the development of mouse tooth germ .%目的:通过观察转录因子FoxO3a在小鼠牙胚发育中的表达特点及分布情况,探讨其在小鼠牙胚发育过程中的作用。方法取出生0 d和3 d的昆明小鼠各3只,处死解剖下颌骨,放于新鲜配置的10%中性甲醛溶液中固定过夜,制备小鼠牙胚0d和3d的组织标本,常规石蜡包埋,近远中向5μm连续切片,采用免疫组化方法观察检测FoxO3 a在小鼠不同时期的牙胚表达情况和分布情况,并对结果进行分析。结果 FoxO3 a在小鼠不同时期的牙胚发育中的分布存在差异,FoxO3a在0d小鼠牙胚中,成牙本质细胞成阴性表达,在3d小鼠牙胚中成牙本质细胞成阳性表达。结论观察FoxO3a在小鼠牙胚发育过程中的表达以及表达的变化,提示FoxO3a可能参与牙本质的形成和矿化。

  8. Analysis of split tooth as an unstudied reason for tooth extraction

    OpenAIRE

    Osaghae, Ifueko Patience; Azodo, Clement Chinedu

    2014-01-01

    Background Split tooth is an unstudied reason for tooth extraction. The purpose of this study was to determine and analyze split tooth as a reason for extraction in a dental clinic in Benin City. Methods The prospective study was carried out on 669 patients having tooth extraction between May, 2005 and December, 2012. Over the period of the study, diagnosis and tooth extraction were done by three dentists of more five years practice experience. The indications for tooth extraction were noted ...

  9. Autocrine and paracrine Shh signaling are necessary for tooth morphogenesis, but not tooth replacement in snakes and lizards (Squamata).

    Science.gov (United States)

    Handrigan, Gregory R; Richman, Joy M

    2010-01-01

    Here we study the role of Shh signaling in tooth morphogenesis and successional tooth initiation in snakes and lizards (Squamata). By characterizing the expression of Shh pathway receptor Ptc1 in the developing dentitions of three species (Eublepharis macularius, Python regius, and Pogona vitticeps) and by performing gain- and loss-of-function experiments, we demonstrate that Shh signaling is active in the squamate tooth bud and is required for its normal morphogenesis. Shh apparently mediates tooth morphogenesis by separate paracrine- and autocrine-mediated functions. According to this model, paracrine Shh signaling induces cell proliferation in the cervical loop, outer enamel epithelium, and dental papilla. Autocrine signaling within the stellate reticulum instead appears to regulate cell survival. By treating squamate dental explants with Hh antagonist cyclopamine, we induced tooth phenotypes that closely resemble the morphological and differentiation defects of vestigial, first-generation teeth in the bearded dragon P. vitticeps. Our finding that these vestigial teeth are deficient in epithelial Shh signaling further corroborates that Shh is needed for the normal development of teeth in snakes and lizards. Finally, in this study, we definitively refute a role for Shh signaling in successional dental lamina formation and conclude that other pathways regulate tooth replacement in squamates.

  10. Development of ISRMS for readability of the text of informed consent for tooth extraction%拔牙知情同意书文本易读性ISRMS的开发研究

    Institute of Scientific and Technical Information of China (English)

    王春燕; 虎斌; 马东

    2011-01-01

    介绍了利用Microsoft Office Access对象、窗体控件、ActiveX控件以及Microsoft Visual Basic for Applications(VBA)等功能优势,以拔牙知情同意为模型,开发主观评价医疗知情同意书文本易读性的信息化系统(ISRMS).指出该系统实现了主观评价操作、实验数据同步收集和实验数据分析的计算机信息化,引入了ActiveX控件形式的视觉模拟评分法量规和临床电子牙位记录工具.%We developed the Information-based Subjective Readability Measuring System (ISRMS) for readability of the text of informed consent for tooth extraction by utilizing the advantages of Microsoft Office Access, window control, ActiveX control, and Microsoft Visual Basic for Applications (VBA). This system has realized subjective evaluation, synchronous collection of experiment data, and analysis of experiment data, introduced the visual analogue scale in the form of ActiveX control and the tool for recording clinical electronic tooth position.

  11. An automatic tooth preparation technique: A preliminary study

    Science.gov (United States)

    Yuan, Fusong; Wang, Yong; Zhang, Yaopeng; Sun, Yuchun; Wang, Dangxiao; Lyu, Peijun

    2016-04-01

    The aim of this study is to validate the feasibility and accuracy of a new automatic tooth preparation technique in dental healthcare. An automatic tooth preparation robotic device with three-dimensional motion planning software was developed, which controlled an ultra-short pulse laser (USPL) beam (wavelength 1,064 nm, pulse width 15 ps, output power 30 W, and repeat frequency rate 100 kHz) to complete the tooth preparation process. A total of 15 freshly extracted human intact first molars were collected and fixed into a phantom head, and the target preparation shapes of these molars were designed using customised computer-aided design (CAD) software. The accuracy of tooth preparation was evaluated using the Geomagic Studio and Imageware software, and the preparing time of each tooth was recorded. Compared with the target preparation shape, the average shape error of the 15 prepared molars was 0.05–0.17 mm, the preparation depth error of the occlusal surface was approximately 0.097 mm, and the error of the convergence angle was approximately 1.0°. The average preparation time was 17 minutes. These results validated the accuracy and feasibility of the automatic tooth preparation technique.

  12. Prospects for tooth regeneration in the 21st century: a perspective.

    Science.gov (United States)

    Chai, Yang; Slavkin, Harold C

    2003-04-01

    The prospects for tooth regeneration in the 21st century are compelling. Using the foundations of experimental embryology, developmental and molecular biology, the principles of biomimetics (the mimicking of biological processes), tooth regeneration is becoming a realistic possibility within the next few decades. The cellular, molecular, and developmental "rules" for tooth morphogenesis are rapidly being discovered. The knowledge gained from adult stem cell biology, especially associated with dentin, cartilage, and bone tissue regeneration, provides additional opportunities for eventual tooth organogenesis. The centuries of tooth development using xenotransplantation, allotransplantation, and autotransplantation have resulted in many important insights that can enhance tooth regeneration. In considering the future, several lines of evidence need to be considered: (1) enamel organ epithelia and dental papilla mesenchyme tissues contain stem cells during postnatal stages of life; (2) late cap stage and bell stage tooth organs contain stem cells; (3) odontogenic adult stem cells respond to mechanical as well as chemical "signals"; (4) presumably adult bone marrow as well as dental pulp tissues contain "odontogenic" stem cells; and (5) epithelial-mesenchymal interactions are pre-requisite for tooth regeneration. The authors express "guarded enthusiasm," yet there should be little doubt that adult stem cell-mediated tooth regeneration will be realized in the not too distant future. The prospects for tooth regeneration could be realized in the next few decades and could be rapidly utilized to improve the quality of human life in many nations around the world.

  13. Analysis of the vibratory excitation of gear systems. II - Tooth error representations, approximations, and application

    Science.gov (United States)

    Mark, W. D.

    1979-01-01

    The second part of a theory for predicting the vibratory excitation of gear systems from fundamental descriptions of gear tooth elastic properties and deviations of tooth faces from perfect involute surfaces is presented. The first part of the theory provides expressions for the Fourier-series coefficients of the vibratory excitation, and this paper gives expressions for these Fourier-series coefficients in terms of easily interpreted gear tooth metrics that are readily evaluated from tooth-face measurements. Results are given for rectangular tooth-face contact regions using two-dimensional Legendre polynomial expansions of local tooth-pair stiffnesses and stiffness-weighted deviations of tooth faces from perfect involute surfaces. A rigorous transfer function approach is developed that permits separation of the effects of gear tooth errors and gear design parameters; the theory is applicable to helical and spur gears and is illustrated with measurements of tooth-spacing errors and tooth profiles obtained from a pair of spur gears.

  14. 14 CFR 1203b.103 - Arrest authority.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Arrest authority. 1203b.103 Section 1203b.103 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SECURITY PROGRAMS; ARREST AUTHORITY AND USE OF FORCE BY NASA SECURITY FORCE PERSONNEL § 1203b.103 Arrest authority. (a) NASA...

  15. 33 CFR 154.822 - Detonation arresters, flame arresters, and flame screens.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Detonation arresters, flame arresters, and flame screens. 154.822 Section 154.822 Navigation and Navigable Waters COAST GUARD... BULK Vapor Control Systems § 154.822 Detonation arresters, flame arresters, and flame screens. (a)...

  16. Tooth wear patterns in the deciduous dentition.

    Science.gov (United States)

    Warren, John J; Yonezu, Takuro; Bishara, Samir E

    2002-12-01

    Tooth wear is common in the deciduous dentition. A recent study suggests that tooth wear in the deciduous dentition is related to subsequent tooth wear in adults, so that early identification of factors related to tooth wear could be of long-term benefit. The purposes of this study were to describe patterns of tooth wear in the deciduous dentition and to relate tooth wear to occlusal characteristics and longitudinal dietary patterns. Data were collected as part of a longitudinal study of a cohort of children recruited at birth from Iowa hospitals. Stone casts were obtained in the deciduous dentition stage, and 355 children, 4 to 5 years old, met the selection criteria. Tooth wear was categorized for each tooth as none, mild, moderate, or severe, and related to occlusal characteristics and longitudinal data on fruit juice and soft drink consumption. All children exhibited some tooth wear on at least 1 tooth, and nearly 16% of them had at least 1 tooth with severe wear. Tooth wear was generally more severe in the maxillary arch and the anterior teeth. Severe tooth wear on the molars was significantly related to posterior crossbites, but severe tooth wear on the incisors was related to Class III canine relationships. There were no statistically significant relationships between tooth wear and soft drink or fruit juice consumption. Based on our results, we concluded that mild tooth wear is universal in the deciduous dentition, but only a few occlusal factors are related to severe tooth wear. Tooth wear was not related to any dietary patterns we investigated.

  17. Shading of ceramic crowns using digital tooth shade matching devices.

    Science.gov (United States)

    Baltzer, A; Kaufmann-Jinoian, V

    2005-04-01

    In the 1990s, there was great optimism due to the development of devices for measuring tooth shade. The frequently not so simple, visual determination of the shade of a tooth was to be done with the aid of a device which recognizes the shade and describes it accurately by reference to a color chart. However, the skepticism towards such devices was also great. It is known that the color effect frequently differs strongly when comparing a tooth from the shade guide with a metal ceramic crown, despite identical shade designation. Anyone who considers visual shade determination to be inadequate and places his hopes in digital shade matching devices will be disappointed. It is the shade-generating structures of the metal ceramic and frequently of the veneer layers that turn out to be too thin which, despite correct shade selection, cause a different color perception. Such problems have been reduced decisively with the development of fracture-proof hard porcelain caps (Vita In-Ceram) with optical characteristics similar to teeth. In addition, the Vita System 3D-Master tooth shade system developed in 1998 by Vita in cooperation with Dr. Hall from Australia, leads the practitioner to a better understanding of the primary tooth shade characteristics of "brightness (value)", "color intensity (chroma)" and "color (wave length of the visible light, hue)". These two innovations allow a more accurate estimate of the basic shade of a natural tooth (reference tooth) and the imitation in the laboratory of its natural, shade-generating structures. If digital shade measurement supplements the visual shade estimate, then a further improvement can be expected--especially in the recognition of the basic shade. Qualitative descriptions of subjective shade measurement of a natural tooth and of its imitation in the dental laboratory by ceramics can be found frequently in professional journals and publications. With digital tooth shade matching devices, which apart from the color code of

  18. Tooth fracture risk analysis based on a new finite element dental structure models using micro-CT data.

    Science.gov (United States)

    Chen, G; Fan, W; Mishra, S; El-Atem, A; Schuetz, M A; Xiao, Y

    2012-10-01

    The finite element (FE) analysis is an effective method to study the strength and predict the fracture risk of endodontically-treated teeth. This paper presents a rapid method developed to generate a comprehensive tooth FE model using data retrieved from micro-computed tomography (μCT). With this method, the inhomogeneity of material properties of teeth was included into the model without dividing the tooth model into different regions. The material properties of the tooth were assumed to be related to the mineral density. The fracture risk at different tooth portions was assessed for root canal treatments. The micro-CT images of a tooth were processed by a Matlab software programme and the CT numbers were retrieved. The tooth contours were obtained with thresholding segmentation using Amira. The inner and outer surfaces of the tooth were imported into Solidworks and a three-dimensional (3D) tooth model was constructed. An assembly of the tooth model with the periodontal ligament (PDL) layer and surrounding bone was imported into ABAQUS. The material properties of the tooth were calculated from the retrieved CT numbers via ABAQUS user's subroutines. Three root canal geometries (original and two enlargements) were investigated. The proposed method in this study can generate detailed 3D finite element models of a tooth with different root canal enlargements and filling materials, and would be very useful for the assessment of the fracture risk at different tooth portions after root canal treatments.

  19. Temporal Differences in Out-of-Hospital Cardiac Arrest Incidence and Survival

    DEFF Research Database (Denmark)

    Bagai, Akshay; McNally, Bryan F; Al-Khatib, Sana M;

    2013-01-01

    Understanding temporal differences in the incidence and outcomes of out-of-hospital cardiac arrest (OHCA) has important implications for developing preventative strategies and optimizing systems for OHCA care.......Understanding temporal differences in the incidence and outcomes of out-of-hospital cardiac arrest (OHCA) has important implications for developing preventative strategies and optimizing systems for OHCA care....

  20. Recent Trends of Technology of Zinc-Oxide Surge Arrester for Electric Power System

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.S.; Kim, K.U.; Cho, H.G. [Korea Electrotechnology Research Institute (Korea); Park, T.G. [Changwon National University (Korea); Park, S.H. [KEPCO (Korea)

    1999-05-01

    Metal-oxide surge arresters were developed in the late 1970s, and were immediately recognized as significant breakthrough in over-voltage protection of power system. Work was continued throughout the world on the design, development and application of metal-oxide surge arresters. (author). 6 refs., 1 fig., 6 tabs.

  1. Tooth polishing: The current status

    Directory of Open Access Journals (Sweden)

    Madhuri Alankar Sawai

    2015-01-01

    Full Text Available Healthy teeth and gums make a person feel confident and fit. As people go about their daily routines and with different eating and drinking habits, the tooth enamel turns yellowish or gets stained. Polishing traditionally has been associated with the prophylaxis procedure in most dental practices, which patients know and expect. However, with overzealous use of polishing procedure, there is wearing of the superficial tooth structure. This would lead to more accumulation of local deposits. Also, it takes a long time for the formation of the fluoride-rich layer of the tooth again. Hence, now-a-days, polishing is not advised as a part of routine oral prophylaxis procedure but is done selectively based on the patients′ need. The article here, gives an insight on the different aspects of the polishing process along with the different methods and agents used for the same.

  2. Tooth polishing: The current status.

    Science.gov (United States)

    Sawai, Madhuri Alankar; Bhardwaj, Ashu; Jafri, Zeba; Sultan, Nishat; Daing, Anika

    2015-01-01

    Healthy teeth and gums make a person feel confident and fit. As people go about their daily routines and with different eating and drinking habits, the tooth enamel turns yellowish or gets stained. Polishing traditionally has been associated with the prophylaxis procedure in most dental practices, which patients know and expect. However, with overzealous use of polishing procedure, there is wearing of the superficial tooth structure. This would lead to more accumulation of local deposits. Also, it takes a long time for the formation of the fluoride-rich layer of the tooth again. Hence, now-a-days, polishing is not advised as a part of routine oral prophylaxis procedure but is done selectively based on the patients' need. The article here, gives an insight on the different aspects of the polishing process along with the different methods and agents used for the same.

  3. Dynamic Assessment of Vibration of Tooth Modification Gearbox Using Grey Bootstrap Method

    Directory of Open Access Journals (Sweden)

    Hui-liang Wang

    2015-01-01

    Full Text Available The correlation analysis between gear modification and vibration characteristics of transmission system was difficult to quantify; a novel small sample vibration of gearbox prediction method based on grey system theory and bootstrap theory was presented. The method characterized vibration base feature of tooth modification gearbox by developing dynamic uncertainty, estimated true value, and systematic error measure, and these parameters could indirectly dynamically evaluate the effect of tooth modification. The method can evaluate the vibration signal of gearbox with installation of no tooth modification gear and topological modification gear, respectively, considering that 100% reliability is the constraints condition and minimum average uncertainty is the target value. Computer simulation and experiment results showed that vibration amplitude of gearbox was decreased partly due to topological tooth modification, and each value of average dynamic uncertainty, mean true value, and systematic error measure was smaller than the no tooth modification value. The study provided an important guide for tooth modification, dynamic performance optimization.

  4. Primary culprit for tooth loss!!

    Directory of Open Access Journals (Sweden)

    Sailavanya Nuvvula

    2016-01-01

    Full Text Available Aim: In order to facilitate planning for dental health services and to progress strategies to continue the reduction in tooth loss, it is important to identify the factors that result in such loss. therefore the aim of the study is to investigate the major cause for tooth extraction. Objective: to examine whether the major reason for tooth extraction is dental caries or periodontal disease. Materials and Methods: The study is carried out among the dental practitioners in our district. A questionnaire containing 10 items was distributed to the dental practitioners, which included age, gender, no of teeth indicated for extraction, the reason for extraction, and the periodontal parameters that are involved with the extracted tooth and were requested to complete the form on every extraction they were to undertake. the study form was collected at the end of the study period and data was subjected to statistical analysis. Results: A total of 502 patients were enrolled during the study period, and a total of 1055 teeth were extracted for several reasons. we found that 51.14%extractions are due to dental caries in case of 20-30years age groups, which is more when compared to tooth loss due to periodontal diseases in this age group. whereas in case of >40years of age group periodontal diseases account for 54.11%, and dental caries accounts for only 29.11%. Showing more teeth were lost due to periodontal disease. Conclusion: therefore we concluded that, caries is the dominant reason for extraction in patients with 20–30 years of age while periodontal disease accounts for the majority of tooth extraction in patients older than 40 years.

  5. Changing the guard: Polymer replaces porcelain for surge arresters

    Energy Technology Data Exchange (ETDEWEB)

    Skytt, T.; Gleimar, H. E. G.

    2002-07-01

    Surge arresters are safety devices which quickly and effectively limit the over voltages that can arise in transmission networks following lightning, switching and other transient events. The earliest forms of overvoltage protection, a simple air gap between electrodes, have long since been replaced by a new generation of gapless arresters with series-connected, non-linear zinc oxide varistors contained in a porcelain housing. Now these porcelain type surge arresters are being replaced by a new type, called PEXLIM (Polymeric EXcellent LIMiter), which uses the same block of zinc oxide as the porcelain type, but its housing is made of silicon rubber, a polymer. The new lightweight insulation material shows a number of properties superior to the porcelain, such as enhanced product safety and ease of handling. It is also more durable, resilient, yet solid and compact, water-repellent, lightweight, resistant to aging or light or ultra-violet radiation, as well as fire, has good electrical properties, and is environmentally friendly since it does not contain any substances harmful to the environment. These properties make this new type of surge arrester highly suitable for use in earthquake-prone areas; it can also replace more expensive and maintenance-intensive equipment. Having successfully broken into the lower voltage systems, these new type of surge arresters are now rapidly gaining ground at the higher voltage levels. ABB, the developer of PEXLIM, has already supplied these arresters to North America for use in an 800-kV grid. As further proof of its growing popularity, last year PEXLIM made up over half of the surge arrester production for applications up to and including 245 kV. 1 tab., 6 figs.

  6. On gear tooth stiffness evaluation

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard; Jørgensen, Martin Felix

    2014-01-01

    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 stiffnesses 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 width is constant. © 2014...

  7. 大鼠肾被膜微环境对牙齿发育的诱导作用%Promoting effect of the sub-renal capsule microenvironment on the development of allotransplanted tooth in rats

    Institute of Scientific and Technical Information of China (English)

    白喜云; 孙耀贵; 李宏全

    2011-01-01

    Objective To explore a suitable culture environment for tissue-engineered teeth and to evaluate the developmental ability of full tooth germs, dental papilla and enamel organ in sub-renal capsule space. Methods Rat fetus at embryonic day 18 (ED18) were obtained by Cesarean section. The full first molar germs were separated from fetus, and to separate them further into enamel organ and dental papilla by microsurgery. Subsequently, full tooth germ, enamel organ and dental papilla were transplanted into sub-renal capsule tissue of adult Sprague-Dawley rat by special glass tube and collected at 2 weeks after grafting. Paraffin sections were prepared and the histological changes of transplants were examined with H&E staining. Results Full tooth germs were well developed into normal shape and structure in the rat sub-renal capsule microenvironment. The dentin-pulp complexes were formed by separated dental papillas. However, the separated enamel organs were not well developed, both tooth crown and enamel were not formed in this group. Conclusions The results of this study indicate that renal subcapsular space is a suitable culture environment for allotransplantated teeth development. After ED18, enamel organ development is still regulated by signals from dental papilla, but in contrast, dental papilla development is no longer dependent on the signals from enamel organ.%目的 为探索一种组织工程化牙齿异位培养的理想环境,检测全牙胚、牙乳头及成釉器在肾被膜环境下的发育能力.方法 利用剖腹产取出胚龄18 d的大鼠胎儿,显微外科分离牙胚,并将之进一步分为牙乳头和成釉器两部分.使用特制玻璃移植管分别将获得的全牙胚、牙乳头及成釉器植入异体大鼠肾被膜下.2周后取出培养物,HE染色观察其发育情况.结果 在肾被膜微环境下,全牙胚在肾被膜下发育良好,形成较为完整的牙齿形态和结构,单独的牙乳头可以形成牙本质,而单独的成釉

  8. Hydroxylated PBDEs induce developmental arrest in zebrafish

    Energy Technology Data Exchange (ETDEWEB)

    Usenko, Crystal Y., E-mail: Crystal_usenko@baylor.edu; Hopkins, David C.; Trumble, Stephen J., E-mail: Stephen_trumble@baylor.edu; Bruce, Erica D., E-mail: Erica_bruce@baylor.edu

    2012-07-01

    The ubiquitous spread of polybrominated diphenyl ethers (PBDEs) has led to concerns regarding the metabolites of these congeners, in particular hydroxylated PBDEs. There are limited studies regarding the biological interactions of these chemicals, yet there is some concern they may be more toxic than their parent compounds. In this study three hydroxylated PBDEs were assessed for toxicity in embryonic zebrafish: 3-OH-BDE 47, 5-OH-BDE 47, and 6-OH-BDE 47. All three congeners induced developmental arrest in a concentration-dependent manner; however, 6-OH-BDE 47 induced adverse effects at lower concentrations than the other congeners. Furthermore, all three induced cell death; however apoptosis was not observed. In short-term exposures (24–28 hours post fertilization), all hydroxylated PBDEs generated oxidative stress in the region corresponding to the cell death at 5 and 10 ppm. To further investigate the short-term effects that may be responsible for the developmental arrest observed in this study, gene regulation was assessed for embryos exposed to 0.625 ppm 6-OH-BDE 47 from 24 to 28 hpf. Genes involved in stress response, thyroid hormone regulation, and neurodevelopment were significantly upregulated compared to controls; however, genes related to oxidative stress were either unaffected or downregulated. This study suggests that hydroxylated PBDEs disrupt development, and may induce oxidative stress and potentially disrupt the cholinergic system and thyroid hormone homeostasis. -- Highlights: ► OH-PBDEs induce developmental arrest in a concentration-dependent manner. ► Hydroxyl group location influences biological interaction. ► OH-PBDEs induce oxidative stress. ► Thyroid hormone gene regulation was disrupted following exposure. ► To our knowledge, this is the first whole organism study of OH-PBDE toxicity.

  9. DAF-16/FOXO regulates transcription of cki-1/Cip/Kip and repression of lin-4 during C. elegans L1 arrest.

    Science.gov (United States)

    Baugh, L Ryan; Sternberg, Paul W

    2006-04-18

    Development is typically studied as a continuous process under laboratory conditions, but wild animals often develop in variable and stressful environments. C. elegans larvae hatch in a developmentally arrested state (L1 arrest) and initiate post-embryonic development only in the presence of food (E. coli in lab). In contrast to the well-studied dauer arrest, L1 arrest occurs without morphological modification, although larvae in L1 arrest are more resistant to environmental stress than developing larvae . Consistent with its role in dauer formation and aging, we show that insulin/insulin-like growth factor (IGF) signaling regulates L1 arrest. daf-2 insulin/IGF receptor mutants have a constitutive-L1-arrest phenotype when fed and extended survival of L1 arrest when starved. Conversely, daf-16/FOXO mutants have a defective-arrest phenotype, failing to arrest development and dying rapidly when starved. We show that DAF-16 is required for transcription of the cyclin-dependent kinase inhibitor cki-1 in stem cells in response to starvation, accounting for the failure of daf-16/FOXO mutants to arrest cell division during L1 arrest. Other developmental events such as cell migration, cell fusion, and expression of the microRNA lin-4, a temporal regulator of post-embryonic development, are also observed in starved daf-16/FOXO mutants. These results suggest that DAF-16/FOXO promotes developmental arrest via transcriptional regulation of numerous target genes that control various aspects of development.

  10. Multidisciplinary Treatment Options of Tooth Avulsion Considering Different Therapy Concepts

    Science.gov (United States)

    Kostka, Eckehard; Meissner, Simon; Finke, Christian H; Mandirola, Manlio; Preissner, Saskia

    2014-01-01

    Background: Avulsion of permanent front teeth is a rare accident, mostly affecting children between seven and nine years of age. Replanted and splinted, these teeth often develop inflammation, severe resorption or ankylosis affecting alveolar bone development and have to be extracted sooner or later. Objectives: The purpose of this study was to evaluate different therapy concepts to create a structured concept for the treatment of avulsions. Results: Based on existing therapy concepts, a concept for different initial conditions (dry time, age, growth, tooth, hard and soft tissues) was developed and is presented here. Conclusion: A great deal of research has been performed during recent years and guidelines for the management of avulsions have been published. With the help of this literature it is possible to identify the best treatment procedure for each tooth. Clinical Relevance: The prognosis of avulsed teeth can be improved by considering evidence-based therapy concepts. Resorption, ankylosis and tooth loss could be minimized. PMID:25352922

  11. Tooth Retained Implant: No More an Oxymoron

    OpenAIRE

    Divya Bhat

    2011-01-01

    Introduction: Periodontally af-fected teeth are treated in one of the two ways. (1) Tooth retention after periodontal surgery, in which the degree of regeneration achieved is unpredictable. (2) Tooth extrac-tion and implant placement. Implants have an osseointegrated surface which does not provide adequate shock absorption. Regeneration can be achieved by resecting the crown of the affected tooth and submerging the root. This technique has not had a clinical application so far as the tooth be...

  12. 21 CFR 872.3920 - Porcelain tooth.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Porcelain tooth. 872.3920 Section 872.3920 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3920 Porcelain tooth. (a) Identification. A porcelain tooth is a prefabricated device made of porcelain powder for clinical use (§ 872.6660) intended for...

  13. Pediatric Charcot-Marie-Tooth disease.

    Science.gov (United States)

    Jani-Acsadi, Agnes; Ounpuu, Sylvia; Pierz, Kristan; Acsadi, Gyula

    2015-06-01

    Heritable diseases of the peripheral nerves (Charcot-Marie-Tooth disease [CMT]) affect the motor units and sensory nerves, and they are among the most prevalent genetic conditions in the pediatric patient population. The typical clinical presentation includes distal muscle weakness and atrophy, but the severity and progression are largely variable. Improvements in supportive treatment have led to better preservation of patients' motor functions. More than 80 genes have been associated with CMT. These genetic discoveries, along with the developments of cellular and transgenic disease models, have allowed clinicians to better understand the disease mechanisms, which should lead to more specific treatments.

  14. Metal oxide surge arrester research at the University of South Australia: An evaluation of polymer housed arresters and a new device for condition monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Baghurst, A.H. [Flinders Univ. of South Australia, Bedford Park, SA (Australia); Buratto, F. [Powercor Australia Ltd., Southbank, VIC (Australia); Krieg, T.W. [ETSA Transmission, Adelaide, SA (Australia)

    1995-12-31

    The use of polymer housed surge arresters within Australia has dramatically increased over the last 2-3 years. Unfortunately, the development of standards for testing polymer housed arresters has not kept pace with the development of these components. This paper describes on-going research at the Australian Electrical Testing Centre, University of South Australia, aimed at furthering knowledge about the performance of metal oxide surge arresters in the field. One project seeks to evaluate a range of polymer-housed arresters from different manufacturers with respect to seal integrity and accelerated ageing under a variety of environmental conditions. Test equipment being developed to perform the tests is described, and those parts of the new draft Australia standard relating to the performance of polymer-housed arresters critically reviewed. A second project involves the development of a new hand-held device for the measurement of that component of arrester leakage current which is in phase with the applied voltage. This parameter is widely accepted as a key indicator of the condition of a metal oxide arrester. The new device should be an order of magnitude cheaper than comparable commercial equipment currently available, and employs a micro controller to perform the required signal processing. (author). 1 tab., 2 figs., 11 refs.

  15. Inhibition of Wnt signaling by Wise (Sostdc1) and negative feedback from Shh controls tooth number and patterning.

    Science.gov (United States)

    Ahn, Youngwook; Sanderson, Brian W; Klein, Ophir D; Krumlauf, Robb

    2010-10-01

    Mice carrying mutations in Wise (Sostdc1) display defects in many aspects of tooth development, including tooth number, size and cusp pattern. To understand the basis of these defects, we have investigated the pathways modulated by Wise in tooth development. We present evidence that, in tooth development, Wise suppresses survival of the diastema or incisor vestigial buds by serving as an inhibitor of Lrp5- and Lrp6-dependent Wnt signaling. Reducing the dosage of the Wnt co-receptor genes Lrp5 and Lrp6 rescues the Wise-null tooth phenotypes. Inactivation of Wise leads to elevated Wnt signaling and, as a consequence, vestigial tooth buds in the normally toothless diastema region display increased proliferation and continuous development to form supernumerary teeth. Conversely, gain-of-function studies show that ectopic Wise reduces Wnt signaling and tooth number. Our analyses demonstrate that the Fgf and Shh pathways are major downstream targets of Wise-regulated Wnt signaling. Furthermore, our experiments revealed that Shh acts as a negative-feedback regulator of Wnt signaling and thus determines the fate of the vestigial buds and later tooth patterning. These data provide insight into the mechanisms that control Wnt signaling in tooth development and into how crosstalk among signaling pathways controls tooth number and morphogenesis.

  16. Tooth extraction by orthodontic force after radiation therapy: report of case

    Energy Technology Data Exchange (ETDEWEB)

    Rodu, B.; Filler, S.J.; Woodfin, G.K.

    1985-12-01

    This report presents a therapeutic approach to orthodontic tooth extraction in a patient at high risk for the development of osteoradionecrosis with conventional techniques. The rationale for this procedure is discussed in detail, combining principles of radiation biology, clinical radiation therapy, and biomechanics of tooth movement.

  17. Reliability of an occlusal and nonocclusal tooth wear grading system: clinical use versus dental cast assessment

    NARCIS (Netherlands)

    Wetselaar, P.; Lobbezoo, F.; Koutris, M.; Visscher, C.M.; Naeije, M.

    2009-01-01

    The reliability of a newly developed tooth wear grading system was assessed both clinically and on dental casts by two observers using 20 participants. The reliability of clinical occlusal/incisal tooth wear grading was fair-to-good to excellent, while that of most of the clinical nonocclusal/noninc

  18. COMPUTED TOMOGRAPHY OF TOOTH RESORPTION IN CATS.

    Science.gov (United States)

    Lang, Linda G; Wilkinson, Thomas E; White, Tammy L; Farnsworth, Raelynn K; Potter, Kathleen A

    2016-09-01

    Tooth resorption is the most common dental disease in cats and can be a source of oral pain. The current clinical gold standard for diagnosis includes a combination of oral exam and dental radiography, however early lesions are not always detected. Computed tomography (CT) of the skull, including the dental arches, is a commonly performed diagnostic procedure, however the appearance of tooth resorption on CT and the diagnostic ability of CT to detect tooth resorption have not been evaluated. The purpose of this prospective, descriptive, diagnostic accuracy study was to characterize the CT appearance of tooth resorption in a sample of affected cats and to evaluate the sensitivity and specificity of CT for tooth resorption compared to the clinical gold standard of oral exam and intraoral dental radiography. Twenty-eight cat cadaver specimens were recruited for inclusion. Each specimen was evaluated using oral exam, intraoral dental radiography, and computed tomography (four different slice thicknesses). Each tooth was evaluated for the presence or absence of tooth resorption. Teeth with lesions and a subset of normal teeth were evaluated with histopathology. On CT, tooth resorption appeared as irregularly marginated hypoattenuating defects in the mineral attenuating tooth components, most commonly involving the root or cementoenamel junction. Sensitivity for CT detection of tooth resorption was fair to poor (42.2-57.7%) and specificity was good to excellent (92.8-96.3%). Findings from this study indicated that CT has high specificity but low sensitivity for detection of tooth resorption in cats.

  19. Jaw lesions associated with impacted tooth: A radiographic diagnostic guide

    Science.gov (United States)

    Mortazavi, Hamed

    2016-01-01

    This review article aimed to introduce a category of jaw lesions associated with impacted tooth. General search engines and specialized databases such as Google Scholar, PubMed, PubMed Central, MedLine Plus, Science Direct, Scopus, and well-recognized textbooks were used to find relevant studies using keywords such as "jaw lesion", "jaw disease", "impacted tooth", and "unerupted tooth". More than 250 articles were found, of which approximately 80 were broadly relevant to the topic. We ultimately included 47 articles that were closely related to the topic of interest. When the relevant data were compiled, the following 10 lesions were identified as having a relationship with impacted tooth: dentigerous cysts, calcifying odontogenic cysts, unicystic (mural) ameloblastomas, ameloblastomas, ameloblastic fibromas, adenomatoid odontogenic tumors, keratocystic odontogenic tumors, calcifying epithelial odontogenic tumors, ameloblastic fibro-odontomas, and odontomas. When clinicians encounter a lesion associated with an impacted tooth, they should first consider these entities in the differential diagnosis. This will help dental practitioners make more accurate diagnoses and develop better treatment plans based on patients' radiographs. PMID:27672610

  20. Canine tooth size and fitness in male mandrills (Mandrillus sphinx).

    Science.gov (United States)

    Leigh, Steven R; Setchell, Joanna M; Charpentier, Marie; Knapp, Leslie A; Wickings, E Jean

    2008-07-01

    Sexual selection theory explains the evolution of exaggerated male morphologies and weaponry, but the fitness consequences of developmental and age-related changes in these features remain poorly understood. This long-term study of mandrill monkeys (Mandrillus sphinx) demonstrates how age-related changes in canine tooth weaponry and adult canine size correlate closely with male lifetime reproductive success. Combining long-term demographic and morphometric data reveals that male fitness covaries simply and directly with canine ontogeny, adult maximum size, and wear. However, fitness is largely independent of other somatometrics. Male mandrills sire offspring almost exclusively when their canines exceed approximately 30 mm, or two-thirds of average adult value (45 mm). Moreover, sires have larger canines than nonsires. The tooth diminishes through wear as animals age, corresponding with, and perhaps influencing, reproductive senescence. These factors combine to constrain male reproductive opportunities to a brief timespan, defined by the period of maximum canine length. Sexually-selected weaponry, especially when it is nonrenewable like the primate canine tooth, is intimately tied to the male life course. Our analyses of this extremely dimorphic species indicate that sexual selection is closely intertwined with growth, development, and aging, pointing to new directions for sexual selection theory. Moreover, the primate canine tooth has potential as a simple mammalian system for testing genetically-based models of aging. Finally, the tooth may record details of life histories in fossil primates, especially when sexual selection has played a role in the evolution of dimorphism.

  1. Jaw lesions associated with impacted tooth: A radiographic diagnostic guide

    Energy Technology Data Exchange (ETDEWEB)

    Motazavi, Hamed; Bharvand, Maryam [Dept. of Oral Medicine, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of)

    2016-09-15

    This review article aimed to introduce a category of jaw lesions associated with impacted tooth. General search engines and specialized databases such as Google Scholar, PubMed, PubMed Central, MedLine Plus, Science Direct, Scopus, and well-recognized textbooks were used to find relevant studies using keywords such as 'jaw lesion', 'jaw disease', 'impacted tooth', and 'unerupted tooth'. More than 250 articles were found, of which approximately 80 were broadly relevant to the topic. We ultimately included 47 articles that were closely related to the topic of interest. When the relevant data were compiled, the following 10 lesions were identified as having a relationship with impacted tooth: dentigerous cysts, calcifying odontogenic cysts, unicystic (mural) ameloblastomas, ameloblastomas, ameloblastic fibromas, adenomatoid odontogenic tumors, keratocystic odontogenic tumors, calcifying epithelial odontogenic tumors, ameloblastic fibro-odontomas, and odontomas. When clinicians encounter a lesion associated with an impacted tooth, they should first consider these entities in the differential diagnosis. This will help dental practitioners make more accurate diagnoses and develop better treatment plans based on patients' radiographs.

  2. Cognitive impairment after sudden cardiac arrest

    OpenAIRE

    Jaszke-Psonka, Magdalena; Piegza, Magdalena; Ścisło, Piotr; Pudlo, Robert; Piegza, Jacek; Badura-Brzoza, Karina; Leksowska, Aleksandra; Hese, Robert T.; Gorczyca, Piotr W.

    2016-01-01

    Aim To evaluate the incidence and severity of the impairment of selected cognitive functions in patients after sudden cardiac arrest (SCA) in comparison to patients after myocardial infarction without SCA and healthy subjects and to analyze the influence of sociodemographic and clinical parameters and the duration of cardiac arrest on the presence and severity of the described disorders. Material and methods The study group comprised 30 cardiac arrest survivors, the reference group comprised ...

  3. Fluoridation and tooth wear in Irish adults.

    LENUS (Irish Health Repository)

    Burke, F M

    2010-10-01

    The aim of this study was to determine the prevalence of tooth wear in adults in Ireland and its relationship with water fluoridation. The National Survey of Adult Oral Health was conducted in 2000\\/2001. Tooth wear was determined using a partial mouth examination assessing the upper and lower anterior teeth. A total of 2456 subjects were examined. In this survey, increasing levels and severity of tooth wear were associated with ageing. Men were more affected by tooth wear and were more likely to be affected by severe tooth wear than women. It was found that age, and gender were significant predictors of tooth wear (P < 0.01). Overall, there was no significant relationship between fluoridation and tooth wear in this study.

  4. Anaphylactic shock and cardiac arrest caused by thiamine infusion

    DEFF Research Database (Denmark)

    Juel, Jacob; Pareek, Manan; Langfrits, Christian Sigvald

    2013-01-01

    intoxication and developed cardiac arrest due to anaphylactic shock following intravenous thiamine infusion. The patient was successfully resuscitated after 15 min and repeated epinephrine administrations. He was discharged in good health after 14 days. This case report emphasises both the importance...

  5. Arresting relaxation in Pickering Emulsions

    Science.gov (United States)

    Atherton, Tim; Burke, Chris

    2015-03-01

    Pickering emulsions consist of droplets of one fluid dispersed in a host fluid and stabilized by colloidal particles absorbed at the fluid-fluid interface. Everyday materials such as crude oil and food products like salad dressing are examples of these materials. Particles can stabilize non spherical droplet shapes in these emulsions through the following sequence: first, an isolated droplet is deformed, e.g. by an electric field, increasing the surface area above the equilibrium value; additional particles are then adsorbed to the interface reducing the surface tension. The droplet is then allowed to relax toward a sphere. If more particles were adsorbed than can be accommodated by the surface area of the spherical ground state, relaxation of the droplet is arrested at some non-spherical shape. Because the energetic cost of removing adsorbed colloids exceeds the interfacial driving force, these configurations can remain stable over long timescales. In this presentation, we present a computational study of the ordering present in anisotropic droplets produced through the mechanism of arrested relaxation and discuss the interplay between the geometry of the droplet, the dynamical process that produced it, and the structure of the defects observed.

  6. Stem cell-based biological tooth repair and regeneration.

    Science.gov (United States)

    Volponi, Ana Angelova; Pang, Yvonne; Sharpe, Paul T

    2010-12-01

    Teeth exhibit limited repair in response to damage, and dental pulp stem cells probably provide a source of cells to replace those damaged and to facilitate repair. Stem cells in other parts of the tooth, such as the periodontal ligament and growing roots, play more dynamic roles in tooth function and development. Dental stem cells can be obtained with ease, making them an attractive source of autologous stem cells for use in restoring vital pulp tissue removed because of infection, in regeneration of periodontal ligament lost in periodontal disease, and for generation of complete or partial tooth structures to form biological implants. As dental stem cells share properties with mesenchymal stem cells, there is also considerable interest in their wider potential to treat disorders involving mesenchymal (or indeed non-mesenchymal) cell derivatives, such as in Parkinson's disease.

  7. Tooth decay -- early childhood

    Science.gov (United States)

    ... 2016 Updated by: Michael Kapner, DDS, General and Aesthetic Dentistry, Norwalk Medical Center, Norwalk, CT. Review provided ... for EHRs For Developers U.S. National Library of Medicine 8600 Rockville Pike, Bethesda, MD 20894 U.S. Department ...

  8. Tooth - abnormal colors

    Science.gov (United States)

    ... 2016 Updated by: Michael Kapner, DDS, general and aesthetic dentistry, Norwalk Medical Center, Norwalk, CT. Review provided ... for EHRs For Developers U.S. National Library of Medicine 8600 Rockville Pike, Bethesda, MD 20894 U.S. Department ...

  9. Tooth - abnormal shape

    Science.gov (United States)

    ... 2016 Updated by: Michael Kapner, DDS, general and aesthetic dentistry, Norwalk Medical Center, Norwalk, CT. Review provided ... for EHRs For Developers U.S. National Library of Medicine 8600 Rockville Pike, Bethesda, MD 20894 U.S. Department ...

  10. Multiple essential MT1-MMP functions in tooth root formation, dentinogenesis, and tooth eruption.

    Science.gov (United States)

    Xu, H; Snider, T N; Wimer, H F; Yamada, S S; Yang, T; Holmbeck, K; Foster, B L

    2016-01-01

    Membrane-type matrix metalloproteinase 1 (MT1-MMP) is a transmembrane zinc-endopeptidase that breaks down extracellular matrix components, including several collagens, during tissue development and physiological remodeling. MT1-MMP-deficient mice (MT1-MMP(-/-)) feature severe defects in connective tissues, such as impaired growth, osteopenia, fibrosis, and conspicuous loss of molar tooth eruption and root formation. In order to define the functions of MT1-MMP during root formation and tooth eruption, we analyzed the development of teeth and surrounding tissues in the absence of MT1-MMP. In situ hybridization showed that MT1-MMP was widely expressed in cells associated with teeth and surrounding connective tissues during development. Multiple defects in dentoalveolar tissues were associated with loss of MT1-MMP. Root formation was inhibited by defective structure and function of Hertwig's epithelial root sheath (HERS). However, no defect was found in creation of the eruption pathway, suggesting that tooth eruption was hampered by lack of alveolar bone modeling/remodeling coincident with reduced periodontal ligament (PDL) formation and integration with the alveolar bone. Additionally, we identified a significant defect in dentin formation and mineralization associated with the loss of MT1-MMP. To segregate these multiple defects and trace their cellular origin, conditional ablation of MT1-MMP was performed in epithelia and mesenchyme. Mice featuring selective loss of MT1-MMP activity in the epithelium were indistinguishable from wild type mice, and importantly, featured a normal HERS structure and molar eruption. In contrast, selective knock-out of MT1-MMP in Osterix-expressing mesenchymal cells, including osteoblasts and odontoblasts, recapitulated major defects from the global knock-out including altered HERS structure, short roots, defective dentin formation and mineralization, and reduced alveolar bone formation, although molars were able to erupt. These data

  11. [Surgical removing of an ectopic tooth in an Iceland mare].

    Science.gov (United States)

    Dicht, S; Del Chicca, F; Fürst, A

    2011-12-01

    Ectopic teeth occur because of failure of the first branchial cleft to close during development and are found mostly in young horses. Such dentigerous cysts are often located at the base of the ear, forming a notable swelling with a fistula, as it was the case with the two year old Iceland mare «Runa». In order to confirm the diagnosis, x-ray images were taken, which is also necessary to locate the ectopic tooth correctly. While operating, the whole cystic membrane should be removed and it is important to prevent adjacent nerves and blood vessels from damage. Prognosis for complete healing after removing an ectopic tooth is excellent.

  12. Tooth sensitivity: mechanisms and management.

    Science.gov (United States)

    Markowitz, K

    1993-08-01

    Tooth sensitivity is a common complaint encountered in clinical practice. Exposed superficial dentin is free of nerve endings, yet sensitive. Experimental evidence indicates that stimuli, such as probing the dentin surface and air blasts, induce fluid movements in the dentinal tubules and these fluid movements, in turn, activate the intradental nerves. The condition of the dentin surface is critically important in allowing this process. In addition, the internal environment of the pulp may influence nerve excitability. Therapies for tooth sensitivity include both agents that obstruct the dentinal tubules and agents that can decrease the excitability of the intradental nerves. The exact treatment used depends on the etiology of the individual's problem and the extent of dentinal tissue damage.

  13. Towards tooth friendly soft drinks.

    Science.gov (United States)

    Kolahi, Jafar; Fazilati, Mohamad; Kadivar, Mahdi

    2009-10-01

    Most soft drinks contain high concentration of simple carbohydrates and have a pH of 3 or even lower. Therefore, they are harmful for tooth structure. A tooth friendly soft drink (T.F.S.D) should have the following characteristics and elements; fluoride (approximately 1 ppm), casein phosphopeptide-amorphous calcium phosphate (2%), xylitol (4-6g/serving), tea polyphenols (2-4 mg/ml), cranberry extract (250 mg/ml of the flavonoids quercetin and myricetin), sugar free, pH close to 5.5 and super oxygenation (240,000 ppm) vs. carbonation. T.F.S.D can be packaged in a container which gaseous oxygen is dissolved in a liquid in the form of bubbles. However, looking at opportunities for so-called sophisticated soft drinks, T.F.S.D will be an example for a functional and health oriented soft drink.

  14. Optical spectroscopy and tooth decay

    Science.gov (United States)

    Misra, P.; De, T.; Singh, R.

    2005-11-01

    Optical spectroscopy in the ultraviolet, visible and mid-infrared spectral regions has been used to discriminate between healthy and diseased teeth of patients in the age range 15-75 years. Spectral scans of absorbance versus wavenumber and fluorescence intensity versus wavelength have been recorded and investigated for caries and periodontal disease. Such optical diagnostics can prove very useful in the early detection and treatment of tooth decay.

  15. Charcot-Marie-Tooth disease.

    LENUS (Irish Health Repository)

    Reilly, Mary M

    2011-03-01

    Charcot-Marie-Tooth (CMT) disease is the commonest inherited neuromuscular disorder affecting at least 1 in 2,500. Over the last two decades, there have been rapid advances in understanding the molecular basis for many forms of CMT with more than 30 causative genes now described. This has made obtaining an accurate genetic diagnosis possible but at times challenging for clinicians. This review aims to provide a simple, pragmatic approach to diagnosing CMT from a clinician\\'s perspective.

  16. A 15-Year Time-series Study of Tooth Extraction in Brazil.

    Science.gov (United States)

    Cunha, Maria Aparecida Goncalves de Melo; Lino, Patrícia Azevedo; Santos, Thiago Rezende Dos; Vasconcelos, Mara; Lucas, Simone Dutra; Abreu, Mauro Henrique Nogueira Guimarães de

    2015-11-01

    Tooth loss is considered to be a public health problem. Time-series studies that assess the influence of social conditions and access to health services on tooth loss are scarce.This study aimed to examine the time-series of permanent tooth extraction in Brazil between 1998 and 2012 and to compare these series in municipalities with different Human Development Index (HDI) scores and with different access to distinct primary and secondary care.The time-series study was performed between 1998 and 2012, using data from the Brazilian National Health Information System. Time-series study was performed between 1998 and 2012. Two annual rates of tooth extraction were calculated and evaluated separately according to 3 parameters: the HDI, the presence of a Dental Specialty Center, and coverage by Oral Health Teams. The time-series was analyzed using a linear regression model.An overall decrease in the tooth-loss tendencies during this period was observed, particularly in the tooth-extraction rate during primary care procedures. In the municipalities with an HDI that was lower than the median, the average tooth-loss rates were higher than in the municipalities with a higher HDI. The municipalities with lower rates of Oral Health Team coverage also showed lower extraction rates than the municipalities with higher coverage rates.In general, Brazil has shown a decrease in the trend to extract permanent teeth during these 15 years. Increased human development and access to dental services have influenced tooth-extraction rates.

  17. Benzyl Isothiocyanate Inhibits Prostate Cancer Development in the Transgenic Adenocarcinoma Mouse Prostate (TRAMP Model, Which Is Associated with the Induction of Cell Cycle G1 Arrest

    Directory of Open Access Journals (Sweden)

    Han Jin Cho

    2016-02-01

    Full Text Available Benzyl isothiocyanate (BITC is a hydrolysis product of glucotropaeolin, a compound found in cruciferous vegetables, and has been shown to have anti-tumor properties. In the present study, we investigated whether BITC inhibits the development of prostate cancer in the transgenic adenocarcinoma mouse prostate (TRAMP mice. Five-week old, male TRAMP mice and their nontransgenic littermates were gavage-fed with 0, 5, or 10 mg/kg of BITC every day for 19 weeks. The weight of the genitourinary tract increased markedly in TRAMP mice and this increase was suppressed significantly by BITC feeding. H and E staining of the dorsolateral lobes of the prostate demonstrated that well-differentiated carcinoma (WDC was a predominant feature in the TRAMP mice. The number of lobes with WDC was reduced by BITC feeding while that of lobes with prostatic intraepithelial neoplasia was increased. BITC feeding reduced the number of cells expressing Ki67 (a proliferation marker, cyclin A, cyclin D1, and cyclin-dependent kinase (CDK2 in the prostatic tissue. In vitro cell culture results revealed that BITC decreased DNA synthesis, as well as CDK2 and CDK4 activity in TRAMP-C2 mouse prostate cancer cells. These results indicate that inhibition of cell cycle progression contributes to the inhibition of prostate cancer development in TRAMP mice treated with BITC.

  18. Nonlinear Simulation of the Tooth Enamel Spectrum for EPR Dosimetry

    Science.gov (United States)

    Kirillov, V. A.; Dubovsky, S. V.

    2016-07-01

    Software was developed where initial EPR spectra of tooth enamel were deconvoluted based on nonlinear simulation, line shapes and signal amplitudes in the model initial spectrum were calculated, the regression coefficient was evaluated, and individual spectra were summed. Software validation demonstrated that doses calculated using it agreed excellently with the applied radiation doses and the doses reconstructed by the method of additive doses.

  19. Psychopathology in Women Arrested for Domestic Violence

    Science.gov (United States)

    Stuart, Gregory L.; Moore, Todd M.; Gordon, Kristina Coop; Ramsey, Susan E.; Kahler, Christopher W.

    2006-01-01

    This study examined the prevalence of psychopathology among women arrested for violence and whether the experience of intimate partner violence (IPV) was associated with Axis I psychopathology. Women who were arrested for domestic violence perpetration and court referred to violence intervention programs (N=103) completed measures of IPV…

  20. Cardiac arrest secondary to type 2 Kounis syndrome resulting from urticaria and angioedema.

    Science.gov (United States)

    Connor, Suzy; Child, Nick; Burdon-Jones, David; Connor, Andrew

    2010-07-01

    A 43-year-old man with no cardiac history presented with chest pain followed by cardiac arrest. He was successfully defibrillated and underwent primary percutaneous coronary angioplasty to a culprit coronary artery lesion. He later re-presented with a diffuse urticarial rash and lip swelling, reporting that these symptoms had been present for 4 weeks before his cardiac arrest and voicing concern that a further cardiac arrest may be imminent. A diagnosis of post-viral or idiopathic autoimmune urticaria and angioedema was made. Given the absence of cardiac symptoms before the development of the rash, it was hypothesised that coronary artery spasm precipitated by histamine release due to his dermatological condition contributed to his myocardial infarction and cardiac arrest. The final diagnosis was therefore cardiac arrest secondary to type II Kounis syndrome, resulting from idiopathic autoimmune or post-viral urticaria and angioedema.

  1. Generation of gear tooth surfaces by application of CNC machines

    Science.gov (United States)

    Litvin, F. L.; Chen, N. X.

    1994-01-01

    This study will demonstrate the importance of application of computer numerically controlled (CNC) machines in generation of gear tooth surfaces with new topology. This topology decreases gear vibration and will extend the gear capacity and service life. A preliminary investigation by a tooth contact analysis (TCA) program has shown that gear tooth surfaces in line contact (for instance, involute helical gears with parallel axes, worm gear drives with cylindrical worms, etc.) are very sensitive to angular errors of misalignment that cause edge contact and an unfavorable shape of transmission errors and vibration. The new topology of gear tooth surfaces is based on the localization of bearing contact, and the synthesis of a predesigned parabolic function of transmission errors that is able to absorb a piecewise linear function of transmission errors caused by gear misalignment. The report will describe the following topics: description of kinematics of CNC machines with six degrees of freedom that can be applied for generation of gear tooth surfaces with new topology. A new method for grinding of gear tooth surfaces by a cone surface or surface of revolution based on application of CNC machines is described. This method provides an optimal approximation of the ground surface to the given one. This method is especially beneficial when undeveloped ruled surfaces are to be ground. Execution of motions of the CNC machine is also described. The solution to this problem can be applied as well for the transfer of machine tool settings from a conventional generator to the CNC machine. The developed theory required the derivation of a modified equation of meshing based on application of the concept of space curves, space curves represented on surfaces, geodesic curvature, surface torsion, etc. Condensed information on these topics of differential geometry is provided as well.

  2. Three dimensional mathematical model of tooth for finite element analysis

    Directory of Open Access Journals (Sweden)

    Puškar Tatjana

    2010-01-01

    Full Text Available Introduction. The mathematical model of the abutment tooth is the starting point of the finite element analysis of stress and deformation of dental structures. The simplest and easiest way is to form a model according to the literature data of dimensions and morphological characteristics of teeth. Our method is based on forming 3D models using standard geometrical forms (objects in programmes for solid modeling. Objective. Forming the mathematical model of abutment of the second upper premolar for finite element analysis of stress and deformation of dental structures. Methods. The abutment tooth has a form of a complex geometric object. It is suitable for modeling in programs for solid modeling SolidWorks. After analyzing the literature data about the morphological characteristics of teeth, we started the modeling dividing the tooth (complex geometric body into simple geometric bodies (cylinder, cone, pyramid,.... Connecting simple geometric bodies together or substricting bodies from the basic body, we formed complex geometric body, tooth. The model is then transferred into Abaqus, a computational programme for finite element analysis. Transferring the data was done by standard file format for transferring 3D models ACIS SAT. Results. Using the programme for solid modeling SolidWorks, we developed three models of abutment of the second maxillary premolar: the model of the intact abutment, the model of the endodontically treated tooth with two remaining cavity walls and the model of the endodontically treated tooth with two remaining walls and inserted post. Conclusion Mathematical models of the abutment made according to the literature data are very similar with the real abutment and the simplifications are minimal. These models enable calculations of stress and deformation of the dental structures. The finite element analysis provides useful information in understanding biomechanical problems and gives guidance for clinical research.

  3. Automating digital leaf measurement: the tooth, the whole tooth, and nothing but the tooth.

    Science.gov (United States)

    Corney, David P A; Tang, H Lilian; Clark, Jonathan Y; Hu, Yin; Jin, Jing

    2012-01-01

    Many species of plants produce leaves with distinct teeth around their margins. The presence and nature of these teeth can often help botanists to identify species. Moreover, it has long been known that more species native to colder regions have teeth than species native to warmer regions. It has therefore been suggested that fossilized remains of leaves can be used as a proxy for ancient climate reconstruction. Similar studies on living plants can help our understanding of the relationships. The required analysis of leaves typically involves considerable manual effort, which in practice limits the number of leaves that are analyzed, potentially reducing the power of the results. In this work, we describe a novel algorithm to automate the marginal tooth analysis of leaves found in digital images. We demonstrate our methods on a large set of images of whole herbarium specimens collected from Tilia trees (also known as lime, linden or basswood). We chose the genus Tilia as its constituent species have toothed leaves of varied size and shape. In a previous study we extracted c.1600 leaves automatically from a set of c.1100 images. Our new algorithm locates teeth on the margins of such leaves and extracts features such as each tooth's area, perimeter and internal angles, as well as counting them. We evaluate an implementation of our algorithm's performance against a manually analyzed subset of the images. We found that the algorithm achieves an accuracy of 85% for counting teeth and 75% for estimating tooth area. We also demonstrate that the automatically extracted features are sufficient to identify different species of Tilia using a simple linear discriminant analysis, and that the features relating to teeth are the most useful.

  4. Automating digital leaf measurement: the tooth, the whole tooth, and nothing but the tooth.

    Directory of Open Access Journals (Sweden)

    David P A Corney

    Full Text Available Many species of plants produce leaves with distinct teeth around their margins. The presence and nature of these teeth can often help botanists to identify species. Moreover, it has long been known that more species native to colder regions have teeth than species native to warmer regions. It has therefore been suggested that fossilized remains of leaves can be used as a proxy for ancient climate reconstruction. Similar studies on living plants can help our understanding of the relationships. The required analysis of leaves typically involves considerable manual effort, which in practice limits the number of leaves that are analyzed, potentially reducing the power of the results. In this work, we describe a novel algorithm to automate the marginal tooth analysis of leaves found in digital images. We demonstrate our methods on a large set of images of whole herbarium specimens collected from Tilia trees (also known as lime, linden or basswood. We chose the genus Tilia as its constituent species have toothed leaves of varied size and shape. In a previous study we extracted c.1600 leaves automatically from a set of c.1100 images. Our new algorithm locates teeth on the margins of such leaves and extracts features such as each tooth's area, perimeter and internal angles, as well as counting them. We evaluate an implementation of our algorithm's performance against a manually analyzed subset of the images. We found that the algorithm achieves an accuracy of 85% for counting teeth and 75% for estimating tooth area. We also demonstrate that the automatically extracted features are sufficient to identify different species of Tilia using a simple linear discriminant analysis, and that the features relating to teeth are the most useful.

  5. Physeal arrest of the distal radius.

    Science.gov (United States)

    Abzug, Joshua M; Little, Kevin; Kozin, Scott H

    2014-06-01

    Fractures of the distal radius are among the most common pediatric fractures. Although most of these fractures heal without complication, some result in partial or complete physeal arrest. The risk of physeal arrest can be reduced by avoiding known risk factors during fracture management, including multiple attempts at fracture reduction. Athletes may place substantial compressive and shear forces across the distal radial physes, making them prone to growth arrest. Timely recognition of physeal arrest can allow for more predictable procedures to be performed, such as distal ulnar epiphysiodesis. In cases of partial arrest, physeal bar excision with interposition grafting can be performed. Once ulnar abutment is present, more invasive procedures may be required, including ulnar shortening osteotomy or radial lengthening.

  6. Visualization of Tooth for Non-Destructive Evaluation from CT Images

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Hui; Chae, Ok Sam [Kyung Hee University, Seoul (Korea, Republic of)

    2009-06-15

    This paper reports an effort to develop 3D tooth visualization system from CT sequence images as a part of the non-destructive evaluation suitable for the simulation of endodontics, orthodontics and other dental treatments. We focus on the segmentation and visualization for the individual tooth. In dental CT images teeth are touching the adjacent teeth or surrounded by the alveolar bones with similar intensity. We propose an improved level set method with shape prior to separate a tooth from other teeth as well as the alveolar bones. Reconstructed 3D model of individual tooth based on the segmentation results indicates that our technique is a very conducive tool for tooth visualization, evaluation and diagnosis. Some comparative visualization results validate the non-destructive function of our method.

  7. Mesenchymal Stem Cells and Tooth Engineering

    Institute of Scientific and Technical Information of China (English)

    Li Peng; Ling Ye; Xue-dong Zhou

    2009-01-01

    Tooth loss compromises human oral health. Although several prosthetic methods, such as artificial denture and dental implants, are clinical therapies to tooth loss problems, they are thought to have safety and usage time issues. Recently, tooth tissue engineering has attracted more and more attention. Stem cell based tissue engineering is thought to be a promising way to replace the missing tooth. Mesenchymal stem cells (MSCs) are multipotent stem cells which can differentiate into a variety of cell types. The potential MSCs for tooth regeneration mainly include stem cells from human exfoliated deciduous teeth (SHEDs), adult dental pulp stem cells (DPSCs), stem cells from the apical part of the papilla (SCAPs), stem cells from the dental follicle (DFSCs), periodontal ligament stem cells (PDLSCs) and bone marrow derived mesenchymal stem cells (BMSCs). This review outlines the recent progress in the mesenchymal stem cells used in tooth regeneration.

  8. Test Tube Tooth: The Next Big Thing

    Science.gov (United States)

    Tahir, Mohammed; Yadav, Harsh; Sureka, Rakshit; Garg, Aarti

    2016-01-01

    Unlike some vertebrates and fishes, humans do not have the capacity for tooth regeneration after the loss of permanent teeth. Although artificial replacement with removable dentures, fixed prosthesis and implants is possible through advances in the field of prosthetic dentistry, it would be ideal to recreate a third set of natural teeth to replace lost dentition. For many years now, researchers in the field of tissue engineering have been trying to bioengineer dental tissues as well as whole teeth. In order to attain a whole tooth through dental engineering, that has the same or nearly same biological, mechanical and physical properties of a natural tooth, it’s necessary to deal with all the cells and tissues which are concerned with the formation, maintenance and repair of the tooth. In this article we review the steps involved in odontogenesis or organogenesis of a tooth and progress in the bioengineering of a whole tooth. PMID:27504430

  9. [Application of micro-power system in the surgery of tooth extraction].

    Science.gov (United States)

    Kaijin, Hu; Yongfeng, Li

    2015-02-01

    Tooth extraction is a common operation in oral surgery. Traditional-extraction instruments, such as bone chisel, elevator, and bone hammer, lead to not only severe trauma but also unnecessary complications, and patients easily become nervous and apprehensive if tooth extraction is performed using these violent instruments. In recent years, with the develop- ment of minimally invasive concept and technology, various micro-power instruments have been used for tooth extraction. This innovative technology can reduce the iatrogenic trauma and complications of tooth extraction. Additionally, this technology can greatly decrease the patient's physical and mental pressure. The new equipment compensates for the deficiency of traditional tooth extraction equipment and facilitates the gradual replacement of the latter. Diverse micro-power systems have distinct strengths and weaknesses, so some auxiliary instruments are still needed during tooth extraction. This paper focuses on the various micro-power systems for tooth extraction and tries to compare the advantages and disadvantages of these systems. Selection and usage of auxiliary equipment are also introduced. Thus, this paper provides reference for the proper application of the micro-power systems in tooth extraction.

  10. Hippo pathway/Yap regulates primary enamel knot and dental cusp patterning in tooth morphogenesis.

    Science.gov (United States)

    Kwon, Hyuk-Jae Edward; Li, Liwen; Jung, Han-Sung

    2015-11-01

    The shape of an individual tooth crown is primarily determined by the number and arrangement of its cusps, i.e., cusp patterning. Enamel knots that appear in the enamel organ during tooth morphogenesis have been suggested to play important roles in cusp patterning. Animal model studies have shown that the Hippo pathway effector Yap has a critical function in tooth morphogenesis. However, the role of the Hippo pathway/Yap in cusp patterning has not been well documented and its specific roles in tooth morphogenesis remain unclear. Here, we provide evidence that Yap is a key mediator in tooth cusp patterning. We demonstrate a correlation between Yap localization and cell proliferation in developing tooth germs. We also show that, between the cap stage and bell stage, Yap is crucial for the suppression of the primary enamel knot and for the patterning of secondary enamel knots, which are the future cusp regions. When Yap expression is stage-specifically knocked down during the cap stage, the activity of the primary enamel knot persists into the bell-stage tooth germ, leading to ectopic cusp formation. Our data reveal the importance of the Hippo pathway/Yap in enamel knots and in the proper patterning of tooth cusps.

  11. Practical whole-tooth restoration utilizing autologous bioengineered tooth germ transplantation in a postnatal canine model

    Science.gov (United States)

    Ono, Mitsuaki; Oshima, Masamitsu; Ogawa, Miho; Sonoyama, Wataru; Hara, Emilio Satoshi; Oida, Yasutaka; Shinkawa, Shigehiko; Nakajima, Ryu; Mine, Atsushi; Hayano, Satoru; Fukumoto, Satoshi; Kasugai, Shohei; Yamaguchi, Akira; Tsuji, Takashi; Kuboki, Takuo

    2017-01-01

    Whole-organ regeneration has great potential for the replacement of dysfunctional organs through the reconstruction of a fully functional bioengineered organ using three-dimensional cell manipulation in vitro. Recently, many basic studies of whole-tooth replacement using three-dimensional cell manipulation have been conducted in a mouse model. Further evidence of the practical application to human medicine is required to demonstrate tooth restoration by reconstructing bioengineered tooth germ using a postnatal large-animal model. Herein, we demonstrate functional tooth restoration through the autologous transplantation of bioengineered tooth germ in a postnatal canine model. The bioengineered tooth, which was reconstructed using permanent tooth germ cells, erupted into the jawbone after autologous transplantation and achieved physiological function equivalent to that of a natural tooth. This study represents a substantial advancement in whole-organ replacement therapy through the transplantation of bioengineered organ germ as a practical model for future clinical regenerative medicine. PMID:28300208

  12. Tooth engineering: searching for dental mesenchymal cells sources.

    Directory of Open Access Journals (Sweden)

    Laetitia eKeller

    2011-03-01

    Full Text Available The implantation of cultured re-associations between embryonic dental mesenchymal cells and epithelial cells from mouse molars at ED14 allowed making full teeth with crown, root, periodontal ligament fibers and bone. Although representing valuable tools to set up methodologies embryonic cells are not easily available. This work thus aimed to replace the embryonic cells by dental mesenchymal cell lines or cultured expanded embryonic cells, and to test their ability to mediate tooth development in vitro when re-associated with a competent dental epithelium. Histology, immunostaining and RT-PCR allowed getting complementary sets of results. Two different immortalized cell lines from ED18 dental mesenchyme failed in mediating tooth formation. The potentialities of embryonic dental mesenchymal cells decreased from ED14 to ED16 and were lost at ED18. This is likely related to a change in the mesenchymal cell phenotype and/or populations during development. Attempts to cultivate ED14 or ED16 embryonic dental mesenchymal cells prior to re-association led to the loss of their ability to support tooth development. This was accompanied by a down-regulation of Fgf3 transcription. Supplementation of the culture medium with FGF2 allowed restoring Fgf3 expression, but not the ability of mesenchymal cells to engage in tooth formation. Altogether, these observations suggest that a competent cell population exists in the dental mesenchyme at ED14, progressively decreases during development, and cannot as such be maintained in vitro. This study evidenced the need for specific conditions to maintain the ability of dental mesenchymal cells to initiate whole tooth formation, when re-associated with an odontogenic epithelium. Efforts to improve the culture conditions will have to be combined with attempts to characterize the competent cells within the dental mesenchyme.

  13. Esthesioneuroblastoma presenting as tooth pain

    Directory of Open Access Journals (Sweden)

    Parvathi Devi

    2014-01-01

    Full Text Available Esthesioneuroblastoma, also called olfactory neuroblastoma, is a rare malignant tumor originating in the olfactory epithelium in the upper nasal cavity with intracranial extension and may also be associated with secondary sinus diseases. Esthesioneuroblastoma has been observed to cause death by distant metastasis or by invasion through the cribriform plate and secondary meningitis. It usually produces nasal obstruction, epistaxis and less commonly anosmia, headache and pain. We report a case of esthesioneuroblastoma in a 50-year-old female who reported with tooth pain as a presenting symptom.

  14. Esthesioneuroblastoma presenting as tooth pain.

    Science.gov (United States)

    Devi, Parvathi; Bhavle, Radhika; Aggarwal, Avanti; Walia, Cherry

    2014-09-01

    Esthesioneuroblastoma, also called olfactory neuroblastoma, is a rare malignant tumor originating in the olfactory epithelium in the upper nasal cavity with intracranial extension and may also be associated with secondary sinus diseases. Esthesioneuroblastoma has been observed to cause death by distant metastasis or by invasion through the cribriform plate and secondary meningitis. It usually produces nasal obstruction, epistaxis and less commonly anosmia, headache and pain. We report a case of esthesioneuroblastoma in a 50-year-old female who reported with tooth pain as a presenting symptom.

  15. Proteoglycans and orthodontic tooth movement.

    Science.gov (United States)

    Waddington, R J; Embery, G

    2001-12-01

    Proteoglycans represent an important and diverse family of extracellular matrix components within the connective tissues of the periodontium. This review focuses on the function and metabolism of the various proteoglycans in periodontal tissues, such as alveolar bone and periodontal ligament, and considers their potential fate in response to an orthodontic force. Such considerations provide an important background in evaluating the potential for proteoglycan metabolites, alongside other connective tissue metabolites, as biomarkers for assessing the deep-seated metabolic changes and as a diagnostic tool in monitoring orthodontic tooth movement.

  16. Chromosomal Aneuploidies and Early Embryonic Developmental Arrest

    Directory of Open Access Journals (Sweden)

    Maria Maurer

    2015-07-01

    Full Text Available Background: Selecting the best embryo for transfer, with the highest chance of achieving a vital pregnancy, is a major goal in current in vitro fertilization (IVF technology. The high rate of embryonic developmental arrest during IVF treatment is one of the limitations in achieving this goal. Chromosomal abnormalities are possibly linked with chromosomal arrest and selection against abnormal fertilization products. The objective of this study was to evaluate the frequency and type of chromosomal abnormalities in preimplantation embryos with developmental arrest. Materials and Methods: This cohort study included blastomeres of embryos with early developmental arrest that were biopsied and analyzed by fluorescence in-situ hybridization (FISH with probes for chromosomes 13, 16, 18, 21 and 22. Forty-five couples undergoing IVF treatment were included, and 119 arrested embryos were biopsied. All probes were obtained from the Kinderwunsch Zentrum, Linz, Austria, between August 2009 and August 2011. Results: Of these embryos, 31.6% were normal for all chromosomes tested, and 68.4% were abnormal. Eleven embryos were uniformly aneuploid, 20 were polyploid, 3 were haploid, 11 displayed mosaicism and 22 embryos exhibited chaotic chromosomal complement. Conclusion: Nearly 70% of arrested embryos exhibit chromosomal errors, making chromosomal abnormalities a major cause of embryonic arrest and may be a further explanation for the high developmental failure rates during culture of the embryos in the IVF setting.

  17. [Cardiopulmonary resuscitation in cardiac arrest following trauma].

    Science.gov (United States)

    Leidel, B A; Kanz, K-G

    2016-11-01

    For decades, survival rates of cardiac arrest following trauma were reported between 0 and 2 %. Since 2005, survival rates have increased with a wide range up to 39 % and good neurological recovery in every second person injured for unknown reasons. Especially in children, high survival rates with good neurologic outcomes are published. Resuscitation following traumatic cardiac arrest differs significantly from nontraumatic causes. Paramount is treatment of reversible causes, which include massive bleeding, hypoxia, tension pneumothorax, and pericardial tamponade. Treatment of reversible causes should be simultaneous. Chest compression is inferior following traumatic cardiac arrest and should never delay treatment of reversible causes of the traumatic cardiac arrest. In massive bleeding, bleeding control has priority. Damage control resuscitation with permissive hypotension, aggressive coagulation therapy, and damage control surgery represent the pillars of initial treatment. Cardiac arrest due to hypoxia should be resolved by airway management and ventilation. Tension pneumothorax should be decompressed by finger thoracostomy, pericardial tamponade by resuscitative thoracotomy. In addition, resuscitative thoracotomy allows direct and indirect bleeding control. Untreated impact brain apnea may rapidly lead to cardiac arrest and requires quick opening of the airway and effective oxygenation. Established algorithms for treatment of cardiac arrest following trauma enable a safe, structured, and effective management.

  18. Theory of dynamic arrest in colloidal mixtures.

    Science.gov (United States)

    Juárez-Maldonado, R; Medina-Noyola, M

    2008-05-01

    We present a first-principles theory of dynamic arrest in colloidal mixtures based on the multicomponent self-consistent generalized Langevin equation theory of colloid dynamics [M. A. Chávez-Rojo and M. Medina-Noyola, Phys. Rev. E 72, 031107 (2005); M. A. Chávez-Rojo and M. Medina-Noyola, Phys. Rev. E76, 039902 (2007)]. We illustrate its application with a description of dynamic arrest in two simple model colloidal mixtures: namely, hard-sphere and repulsive Yukawa binary mixtures. Our results include observation of the two patterns of dynamic arrest, one in which both species become simultaneously arrested and the other involving the sequential arrest of the two species. The latter case gives rise to mixed states in which one species is arrested while the other species remains mobile. We also derive the ("bifurcation" or fixed-point") equations for the nonergodic parameters of the system, which takes the surprisingly simple form of a system of coupled equations for the localization length of the particles of each species. The solution of this system of equations indicates unambiguously which species is arrested (finite localization length) and which species remains ergodic (infinite localization length). As a result, we are able to draw the entire ergodic-nonergodic phase diagram of the binary hard-sphere mixture.

  19. A case of recurrent neuro-Behçet's disease after tooth extraction.

    Science.gov (United States)

    Choi, Seong-Min; Choi, Yun-Ju; Kim, Joon-Tae; Lee, Seung-Han; Park, Man-Seok; Kim, Byeong-Chae; Kim, Myeong-Kyu; Cho, Ki-Hyun

    2010-01-01

    We report a 39-yr-old man with neuro-Behçet's disease (NBD) in remission who developed left-sided ataxia with a sensory deficit about 10 days after tooth extraction. Several years ago, he experienced a similar episode of relapse after tooth extraction. Brain magnetic resonance imaging showed a newly developed right thalamic lesion. In cerebrospinal fluid, lymphocyte-dominant pleocytosis and mild elevation of IgG were found. Immunologic factors may be important in the pathogenesis of NBD because of the time delay between tooth extraction and relapse. Careful observation and prevention are needed before dental procedures in patients with NBD.

  20. 转化生长因子β3在小鼠牙胚钟状晚期以后发育中的表达和分布%Expression and distribution of transforming growth factor β3 in the mouse tooth germ during development after advanced bell stage

    Institute of Scientific and Technical Information of China (English)

    阙国鹰; 李恒; 张磊; 邹莉; 吴英

    2011-01-01

    Objective To observe the expression and distribution of transforming growth factor β3 (TGF-β3) in the mouse tooth germ after advanced bell stage, and to discuss the role of TGFβ3 during the development of tooth germs.Methods BALB/C's mouse tooth germs at 4, 11, and 18 days postnatal (4dpn, 11 dpn, and 18 dpn) were collected and processed for routine fixation,decalcification, embedding, and slicing.The expression of TGF-β3 was detected by immunohistochemisty.Results As to 4dpn tooth germ: Positive expression of TGF-β3 was found in enameloblasts, odontoblasts, ambitus of dental pupilla, with weak positive expression in the intermedial of dental papilla.As to 11 dpn tooth germ: Positive expression was seen in enameloblasts, with negative expression in odontoblasts and dental papilla.As to 18dpn tooth, positive expression of TGF-β3 was showed in the vessel wall and its surrounding, with negative expression in other areas.Conclusion The distribution of TGF-β3 expression showed a time-space characteristic during the mouse tooth germ development after advanced bell stage, which may exert a regulatory effect on tooth development and this effect is gradually getting weak with the development of tooth germs.%目的:观察转化生长因子β3(transforming growth factor β3,TGF-β3)在小鼠牙胚钟状晚期以后发育中的表达分布,探讨其在小鼠牙胚钟状晚期以后发育中的作用.方法:取近交系BALB/C小鼠出生后4 d (4 days postnatal,4dpn)、11 d (11dpn)及18 d (18dpn)的牙胚,常规固定、脱钙、包埋、切片,用SP法免疫组织化学染色技术检测TGF-β3 在各牙胚中的表达.结果:4dpn牙胚成釉细胞层、成牙本质细胞层呈强阳性表达,牙乳头周边区域细胞呈阳性表达,中间区域呈弱阳性表达;11dpn牙胚成釉细胞层呈弱阳性表达,成牙本质细胞层、牙乳头细胞呈阴性表达;18dpn牙胚牙周膜中的血管壁及周围呈强阳性表达,牙本质、牙骨质、牙周膜成纤维

  1. Cardiac Arrest: Obstetric CPR/ACLS.

    Science.gov (United States)

    Cobb, Benjamin; Lipman, Steven

    2017-01-10

    In contrast with other high-resource countries, maternal mortality has seen an increase in the United States. Caring for pregnant women in cardiac arrest may prove uniquely challenging given the rarity of the event coupled by the physiological changes of pregnancy. Optimization of resuscitative efforts warrants special attention as described in the 2015 American Heart Association's "Scientific Statement on Maternal Cardiac Arrest." Current recommendations address a variety of topics ranging from the basic components of chest compressions and airway management to some of the logistical complexities and operational challenges involved in maternal cardiac arrest.

  2. The Petrographic Distinction between Basalt and Andesite Based upon the Arrested Fractionation of Plagioclase Phenocrysts.

    Science.gov (United States)

    Garlick, G. Donald; Garlick, Benjamin J.

    1987-01-01

    Discusses the need to take into account the effects of arrested fractional crystallization in the petrographic classification of volcanic rocks containing plagioclase phenocrysts. Describes the development and use of a computer program to accomplish this task graphically. (TW)

  3. Development of an electro-thermal model for ZnO surge arrester under contamination; Desarrollo de un modelo electro-termico para apartarrayos de ZnO bajo contaminacion

    Energy Technology Data Exchange (ETDEWEB)

    Guardado Zavala, J.L.; Moreno Barraza, M.; Zazueta Pena, H.; Venegas Rebollar, V.; Melgoza Vazquez, E. [Instituto Tecnologico de Morelia, Morelia, Michoacan (Mexico)]. E-mail: lguarda@prodigy.net.mx; hzazuetapea@yahoo.com; vvenegas@yahoo.com; emelgoza@iimorelia.edu.mx

    2010-01-15

    An electro-thermal model for a Zinc Oxide (ZnO) surge arrester under contamination test is presented. The model is based in three sub-models: electrical, thermal and contamination, which interact in order to obtain the surge arrester performance under contamination tests. The electrical model is obtained from measurements and is based on a capacitance and a non-linear resistor. The thermal model takes into account the heat generated and dissipated by the column of varistors and its surroundings. The contamination is represented by dynamic impedance obtained from measurements in the arrester column during contamination tests. The full model is validated by calculating the temperature increase during contamination tests carried out in a two units ZnO surge arrester, class 190 kV. Finally, the results of the effect of several design and construction parameters in the voltage and temperature distribution in the arrester column during contamination tests are presented. [Spanish] Se presenta el modelo electro-termico para un apartarrayos de Oxido de Zinc (ZnO) durante pruebas de contaminacion. El modelo esta compuesto de tres sub-modelos: electrico, termico y de contaminacion, los cuales interactuan armonicamente para obtener el comportamiento del apartarrayos durante pruebas de contaminacion. El modelo electrico se obtiene de mediciones y esta compuesto de una capacitancia y una resistencia no-lineal. El modelo termico considera el calor generado y disipado en la columna de varistores y su entorno. La contaminacion se representa como una impedancia dinamica, cuyos valores se obtienen de mediciones en la columna del apartarrayos durante pruebas de contaminacion. El modelo se valida determinando el incremento de temperatura durante pruebas de contaminacion en un apartarrayos de ZnO de dos unidades clase 1990 kV. Finalmente, se presentan los resultados del impacto de diversos parametros de diseno y construccion en la distribucion de voltaje y temperatura en el apartarrayos

  4. Pediatric tooth extractions under sedoanalgesia

    Science.gov (United States)

    Arpaci, Ayse Hande; Isik, Berrin

    2016-01-01

    Objective: The present study aims to evaluate intravenous ketamine and inhalation sedation in children, their unwanted side-effects and surgeon satisfaction. Methods: In this study, data of 922 children aged between 1-18 who underwent tooth extraction under sedoanalgesia in our department between September 2015-January 2016 were gathered and anesthesia approaches, unwanted side effects and surgical satisfaction was investigated. Postoperative recovery emergence agitation or delirium was evaluated with Watcha Behavior Scale (WBS). Results: Patients were grouped and compared according to acceptance of intravenous line placement (Group-1) or not (Group- 2). Group 1 received intravenous ketamine anesthesia (n=822), Group 2 received inhalation anesthesia with sevoflurane (n=100). Number of patients, age, weight and gender was significantly different in two groups. When side effects were investigated nausea was observed in 30 patients (3.6%), skin rashes were observed in 26 patients (3.2%) in Group-1 while skin rashes were observed in one patient (1%) in Group 2. 95% of surgeons reported intravenous anesthesia, 18% of surgeons reported inhalation anesthesia to be the anesthesia of choice. Emergence of postoperative recovery agitation (WBS≥3) was observed more frequent in Group 2 (p<0.05) than Group 1. Conclusion: Ketamine, which has analgesic, hypnotic and amnestic effects and which does not alter pharyngeal and laryngeal reflexes thus minimizes aspiration possibility, is a safe and effective anesthetic agent for tooth extractions of the pediatric population under sedoanalgesia. PMID:27882039

  5. Diagnosis of Charcot-Marie-Tooth Disease

    Directory of Open Access Journals (Sweden)

    Isabel Banchs

    2009-01-01

    Full Text Available Charcot-Marie-Tooth (CMT disease or hereditary motor and sensory neuropathy (HMSN is a genetically heterogeneous group of conditions that affect the peripheral nervous system. The disease is characterized by degeneration or abnormal development of peripheral nerves and exhibits a range of patterns of genetic transmission. In the majority of cases, CMT first appears in infancy, and its manifestations include clumsiness of gait, predominantly distal muscular atrophy of the limbs, and deformity of the feet in the form of foot drop. It can be classified according to the pattern of transmission (autosomal dominant, autosomal recessive, or X linked, according to electrophysiological findings (demyelinating or axonal, or according to the causative mutant gene. The classification of CMT is complex and undergoes constant revision as new genes and mutations are discovered. In this paper, we review the most efficient diagnostic algorithms for the molecular diagnosis of CMT, which are based on clinical and electrophysiological data.

  6. Apical Revascularization after Delayed Tooth Replantation: An Unusual Case

    Science.gov (United States)

    Nelson-Filho, Paulo; Silva, Lea Assed Bezerra; Silva, Raquel Assed Bezerra; de Carvalho, Fabricio Kitazono; de Queiroz, Alexandra Mussolino

    2016-01-01

    The aim of this paper is to present the clinical and radiological outcome of the treatment involving a delayed tooth replantation after an avulsed immature permanent incisor, with a follow-up of 1 year and 6 months. An 8-year-old boy was referred after dental trauma that occurred on the previous day. The permanent maxillary right central incisor (tooth 11) had been avulsed. The tooth was hand-held during endodontic therapy and an intracanal medication application with calcium hydroxide-based paste was performed. An apical plug with mineral trioxide aggregate (MTA) was introduced into the apical portion of the canal. When the avulsed tooth was replanted with digital pressure, a blood clot had formed within the socket, which moved the MTA apical plug about 2 mm inside of the root canal. These procedures developed apical revascularization, which promoted a successful endodontic outcome, evidenced by apical closure, slight increase in root length, and absence of signs of external root resorption, during a follow-up of 1 year and 6 months. PMID:27882250

  7. Effectiveness of LANAP over time as measured by tooth loss.

    Science.gov (United States)

    Tilt, Lloyd V

    2012-01-01

    This study examines the effectiveness of the laser-assisted new attachment procedure (LANAP) as measured by tooth loss, comparing data to published studies using conventional surgical treatment modalities for the primary treatment of Types III and IV periodontitis. Retrospective data from 107 patients presenting with Types III and IV periodontitis were gathered and evaluated. All patients received LANAP periodontal therapy as their primary surgical treatment according to the FDA-cleared LANAP protocol. The patients averaged 6.2 years post-treatment. The data were compared to several published studies for outcome classification and tooth loss over time. The effectiveness of LANAP as a primary treatment method for Types III and IV periodontitis compares very favorably with conventional surgical treatment modalities concerning tooth loss and stability over time, need for surgical retreatment, and outcome classification. Dentistry continues to develop less invasive means of providing patient care without sacrificing results. Less invasive treatment of periodontitis, with reduced postoperative morbidity yet equal results in tooth retention over time is an important goal. LANAP treatment for moderate and advanced periodontitis provides a less invasive treatment alternative for the dentist and patient to consider as a part of informed consent.

  8. Apical Revascularization after Delayed Tooth Replantation: An Unusual Case

    Directory of Open Access Journals (Sweden)

    Marília Pacífico Lucisano

    2016-01-01

    Full Text Available The aim of this paper is to present the clinical and radiological outcome of the treatment involving a delayed tooth replantation after an avulsed immature permanent incisor, with a follow-up of 1 year and 6 months. An 8-year-old boy was referred after dental trauma that occurred on the previous day. The permanent maxillary right central incisor (tooth 11 had been avulsed. The tooth was hand-held during endodontic therapy and an intracanal medication application with calcium hydroxide-based paste was performed. An apical plug with mineral trioxide aggregate (MTA was introduced into the apical portion of the canal. When the avulsed tooth was replanted with digital pressure, a blood clot had formed within the socket, which moved the MTA apical plug about 2 mm inside of the root canal. These procedures developed apical revascularization, which promoted a successful endodontic outcome, evidenced by apical closure, slight increase in root length, and absence of signs of external root resorption, during a follow-up of 1 year and 6 months.

  9. Addressing Tooth Decay in Head Start Children

    Science.gov (United States)

    Knowlden, Adam P.; Hill, Lawrence F.; Alles-White, Monica L.; Cottrell, Randall R.

    2012-01-01

    Tooth decay is the most prevalent chronic disease of childhood. Oral health education and dental services are crucial to reducing the number of children afflicted with dental cavities. Due to limited access to preventative care, Head Start children are particularly vulnerable to tooth decay. This article outlines practical implications of a…

  10. Zinc Oxide Surge Arresters and HVDC 125kV-upgrade 500kV Converter Stations

    Science.gov (United States)

    Shirakawa, Shingo; Kobayashi, Takayuki; Matsushita, Yoshinao; Sakai, Takehisa; Suzuki, Hironori; Ozaki, Yuzo

    Gapless Metal (Zinc) Oxide Surge Arresters for a.c. systems contribute to the insulation co-ordination based on the suppression of lightning surges and switching surges. These gapless metal oxide surge arresters using ZnO elements are effective to HVDC systems. This paper describes basic characteristics of ZnO (zinc oxide) elements for d.c. systems and applications of gapless surge arresters to HVDC 125kV frequency converters, HVDC 250kV, upgrade HVDC 500kV converter stations, and HVDC 500kV cables of Japan through the experience of developments and applications of gapless metal oxide surge arresters.

  11. Protection against lightning surges provided by line arresters - Furnas' experience on 138 kV system

    Energy Technology Data Exchange (ETDEWEB)

    Camara, Alessandra S.B.; Esmeraldo, Paulo C.V.; Nigri, Armando [FURNAS Centrais Eletricas S.A., Rio de Janeiro, RJ (Brazil)

    1999-07-01

    Furnas is about to make use of the line surge arrester technology in its network, based on studies that have been developed regarding with line performance improvement. In association to such studies, Furnas has installed six line arresters units on a 138 kV line with an arrester manufacturer cooperation, in order to get some experience on installation and maintenance, besides lightning incidence monitoring and line arrester behavior analysis. This paper presents first results and conclusions related to this 138 kV experimental installation on Furnas system. (author)

  12. Autogenous Transplantation for Replacing a Hopeless Tooth

    Science.gov (United States)

    Zakershahrak, Mehrsa; Moshari, Amirabbas; Vatanpour, Mehdi; Khalilak, Zohreh; Jalali Ara, Afsoon

    2017-01-01

    Autogenous tooth transplantation (ATT) is a simple and reasonable choice for replacing the missing teeth when a proper donor tooth is available. This report presents a case of successful ATT of a maxillary right third molar for replacement of mandibular right second molar with a concomitant endodontic-periodontal disease. The mandibular second molar was believed to be hopeless due to a severe damage to coronal tooth structure, inappropriate root canal treatment and apical radiolucency. After extraction of mandibular second molar and maxillary third molar (the donor), the tooth was re-implanted into the extracted socket of second molar site. Root canal therapy was then performed. After 3 years, clinical and radiographic examinations revealed satisfying results, with no signs and symptoms. The patient is asymptomatic and the transplanted tooth is still functional with no signs of marginal periodontal pathosis. Radiographies showed bone regeneration in the site of previous extensive periapical lesion, normal periodontal ligament with no signs of root resorption. PMID:28179939

  13. Biologically Based Restorative Management of Tooth Wear

    Directory of Open Access Journals (Sweden)

    Martin G. D. Kelleher

    2012-01-01

    Full Text Available The prevalence and severity of tooth wear is increasing in industrialised nations. Yet, there is no high-level evidence to support or refute any therapeutic intervention. In the absence of such evidence, many currently prevailing management strategies for tooth wear may be failing in their duty of care to first and foremost improve the oral health of patients with this disease. This paper promotes biologically sound approaches to the management of tooth wear on the basis of current best evidence of the aetiology and clinical features of this disease. The relative risks and benefits of the varying approaches to managing tooth wear are discussed with reference to long-term follow-up studies. Using reference to ethical standards such as “The Daughter Test”, this paper presents case reports of patients with moderate-to-severe levels of tooth wear managed in line with these biologically sound principles.

  14. Stunted root development: A rare dental complication of Stevens-Johnson syndrome

    Science.gov (United States)

    Sangwan, Aditi; Sangwan, Pankaj; Dahiya, Parveen

    2016-01-01

    Stevens-Johnson syndrome (SJS) is a severe cutaneous reaction seen rarely in clinical practice. Most often, it occurs as an adverse reaction to certain drugs. When it affects children at a very young age, arrested tooth root development may also be seen. We present a case of a 13 year old boy who suffered from SJ syndrome at the age of 7 years. Incomplete root development was observed in all teeth, as demonstrated by panaromic radiography. Clinical features of this condition and its management are further discussed. We aim to emphasise on the need for dental practitioners to be aware of the potential dental complications of SJS and enable them to recognise and manage the condition at the earliest so as to avoid any undesirable sequelae. Key words:Adverse drug reaction, amoxycillin, arrested root development, Stevens-Johnson syndrome. PMID:27703617

  15. Coxa vara with proximal femoral growth arrest in patients who had neonatal extracorporeal membrane oxygenation.

    Science.gov (United States)

    DiFazio, Rachel L; Kocher, Minider S; Berven, Sigurd; Kasser, James

    2003-01-01

    This is a retrospective review of four patients in whom a pattern of coxa vara with proximal femoral growth arrest and metaphyseal irregularities developed. These patients were all treated with neonatal extracorporeal membrane oxygenation and presented with a progressive gait disturbance and pain, leg-length discrepancy, and limited abduction. Imaging revealed coxa vara with proximal femoral growth arrest. Two patients (three hips) underwent proximal femoral valgus osteotomy, one patient underwent fixation of a femoral neck fracture with subsequent greater trochanter transfer, and one patient is being observed. This case series suggests an association between neonatal extracorporeal membrane oxygenation and this unusual pattern of coxa vara with proximal femoral growth arrest.

  16. A palmitoyl conjugate of insect pentapeptide Yamamarin arrests cell proliferation and respiration.

    Science.gov (United States)

    Sato, Yosinori; Yang, Ping; An, Ying; Matsukawa, Kazushige; Ito, Kikukatsu; Imanishi, Shigeo; Matsuda, Hirokazu; Uchiyama, Yusuke; Imai, Kunio; Ito, Shigeki; Ishida, Yoji; Suzuki, Koichi

    2010-05-01

    A palmitoyl conjugate of an insect pentapeptide that occurs in diapausing insects causes a reversible cell-cycle arrest and suppresses mitochondrial respiration. This peptide compound also causes growth arrest in murine leukemic cell line expressing human gene Bcr/Abl and a farnesoyl peptide induces embryonic diapause in Bombyx mori. These results demonstrate that the insect peptide compounds can lead to the understanding of a common pathway in developmental arrest in animals and may provide a new peptidominetic analog in the development of biopharmaceuticals and pest management.

  17. The obesity paradox in cardiac arrest patients.

    Science.gov (United States)

    Chalkias, Athanasios; Xanthos, Theodoros

    2014-02-01

    Evidence from clinical cohorts indicates an obesity paradox in overweight and obese patients who seem to have a more favorable short-term and long-term prognosis than leaner patients. Although obese cardiac arrest victims are theoretically more difficult to be resuscitated due to difficulties in providing adequate chest compressions, ventilation, and oxygenation, research so far has shown that there is an obesity paradox in cardiac arrest.

  18. The Prx1 Homeobox Gene is Critical for Molar Tooth Morphogenesis

    OpenAIRE

    Mitchell, J M; Hicklin, D.M.; Doughty, P.M.; Hicklin, J.H.; Dickert, J.W.; Tolbert, S.M.; Peterkova, R.; Kern, M.J.

    2006-01-01

    The paired-related homeobox genes, Prx1 and Prx2, encode transcription factors critical for orofacial development. Prx1-/-/Prx2-/- neonates have mandibular hypoplasia and malformed mandibular incisors. Although the mandibular incisor phenotype has been briefly described (ten Berge et al., 1998, 2001; Lu et al., 1999), very little is known about the role of Prx proteins during tooth morphogenesis. Since the posterior mandibular region was relatively normal, we examined molar tooth development ...

  19. Surface Electrocardiogram Predictors of Sudden Cardiac Arrest

    Science.gov (United States)

    Abdelghani, Samy A.; Rosenthal, Todd M.; Morin, Daniel P.

    2016-01-01

    Background: Heart disease is a major cause of death in industrialized nations, with approximately 50% of these deaths attributable to sudden cardiac arrest. If patients at high risk for sudden cardiac arrest can be identified, their odds of surviving fatal arrhythmias can be significantly improved through prophylactic implantable cardioverter defibrillator placement. This review summarizes the current knowledge pertaining to surface electrocardiogram (ECG) predictors of sudden cardiac arrest. Methods: We conducted a literature review focused on methods of predicting sudden cardiac arrest through noninvasive electrocardiographic testing. Results: Several electrocardiographic-based methods of risk stratification of sudden cardiac arrest have been studied, including QT prolongation, QRS duration, fragmented QRS complexes, early repolarization, Holter monitoring, heart rate variability, heart rate turbulence, signal-averaged ECG, T wave alternans, and T-peak to T-end. These ECG findings have shown variable effectiveness as screening tools. Conclusion: At this time, no individual ECG finding has been found to be able to adequately stratify patients with regard to risk for sudden cardiac arrest. However, one or more of these candidate surface ECG parameters may become useful components of future multifactorial risk stratification calculators. PMID:27660578

  20. Anaphylaxis with Latrodectus Antivenin Resulting in Cardiac Arrest

    OpenAIRE

    Murphy, Christine M.; Hong, Jeannie J.; Beuhler, Michael C.

    2011-01-01

    Latrodectus mactans antivenin is a safe and effective therapy for severe black widow spider envenomations when given to most patients. We report a case of a 37-year-old male with a history of asthma that was given L. mactans antivenin for symptoms related to a black widow envenomation and developed a severe anaphylactic reaction resulting in cardiac arrest. When traditional therapies failed, the patient was given methylene blue for anaphylactic shock resulting in a 30-h period of hemodynamic ...

  1. Prosthetic clone and natural human tooth comparison by speckle interferometry

    Science.gov (United States)

    Slangen, Pierre; Corn, Stephane; Fages, Michel; Raynal, Jacques; Cuisinier, Frederic J. G.

    2010-09-01

    New trends in dental prosthodontic interventions tend to preserve the maximum of "body" structure. With the evolution of CAD-CAM techniques, it is now possible to measure "in mouth" the remaining dental tissues. The prosthetic crown is then designed using this shape on which it will be glued on, and also by taking into account the contact surface of the opposite jaw tooth. Several theories discuss on the glue thickness and formulation, but also on the way to evolve to a more biocompatible crown and also new biomechanical concepts. In order to validate these new concepts and materials, and to study the mechanical properties and mechanical integrity of the prosthesis, high resolution optical measurements of the deformations of the glue and the crown are needed. Samples are two intact premolars extracted for orthodontics reasons. The reference sample has no modifications on the tooth while the second sample tooth is shaped to receive a feldspathic ceramic monoblock crown which will be glued. This crown was manufactured with a chairside CAD-CAM system from an intra-oral optical print. The software allows to realize a nearly perfect clone of the reference sample. The necessary space for the glue is also entered with ideal values. This duplication process yields to obtain two samples with identical anatomy for further processing. The glue joint thickness can also be modified if required. The purpose is to compare the behaviour of a natural tooth and its prosthetic clone manufactured with "biomechanical" concepts. Vertical cut samples have been used to deal with planar object observation, and also to look "inside" the tooth. We have developed a complete apparatus enabling the study of the compressive mechanical behaviour of the concerned tooth by speckle interferometry. Because in plane displacements are of great interest for orthodontic measurements1, an optical fiber in-plane sensitive interferometer has been designed. The fibers are wrapped around piezoelectric

  2. Evaluation of the force applied by the tongue and lip on the maxillary central incisor tooth

    OpenAIRE

    Valentim,Amanda Freitas; Furlan,Renata Maria Moreira Moraes; Perilo,Tatiana Vargas de Castro; Berbert, Monalise Costa Batista; Motta, Andréa Rodrigues; Casas, Estevam Barbosa de Las

    2014-01-01

    PURPOSE: To describe the development and testing of a system that measures forces exerted by the tongue and upper lip on a tooth during rest and during swallowing. METHODS: Twenty-eight subjects, aged 19-31 years (mean: 23.2 years) were submitted to measurement of forces exerted by the upper lip and tongue on the maxillary right central incisor tooth. Flexiforce resistive sensors were fixed on the labial and lingual surfaces of the tooth. They were connected to an amplifier circuit and a data...

  3. Reliability of an occlusal and nonocclusal tooth wear grading system: clinical use versus dental cast assessment.

    Science.gov (United States)

    Wetselaar, Peter; Lobbezoo, Frank; Koutris, Michail; Visscher, Corine M; Naeije, Machiel

    2009-01-01

    The reliability of a newly developed tooth wear grading system was assessed both clinically and on dental casts by two observers using 20 participants. The reliability of clinical occlusal/incisal tooth wear grading was fair-to-good to excellent, while that of most of the clinical nonocclusal/nonincisal grades was at least fair-to-good. Dental cast assessment frequently yielded poor reliabilities, especially for nonocclusal/nonincisal surfaces. Hence, occlusal/incisal wear could be graded more reliably than nonocclusal/nonincisal wear, while the clinical assessment of tooth wear was more reliable than the grading of dental casts.

  4. Local synthesis and tooth contact analysis of face-milled spiral bevel gears

    Science.gov (United States)

    Litvin, F. L.; Zhang, Y.; Handschuh, R. F.

    1991-01-01

    A new approach is proposed for the local synthesis of spiral bevel gears. The approach provides contact at the mean contact point with the desired deviation of the transmission error function by a predesigned parabolic function. The orientation of the contact path on the gear tooth surface and the length of the major axis of the instantaneous contact ellipse are also included in the analysis. A tooth contact analysis (TCA) computer program was developed to simulate meshing and contact of the gear tooth surfaces. A numerical example of the process is given.

  5. Autogenous tooth transplants for the pediatric dental patient: report of three cases.

    Science.gov (United States)

    Kennedy, David

    2013-01-01

    There are select instances where autogenous tooth transplantation should be considered as part of the overall management of the developing occlusion in the child patient. These circumstances occur when there are missing mandibular premolars in Class II malocclusions with good faces, unevenly distributed agenesis, missing or lost incisors, and ectopic teeth. The purposes of this paper were to educate pediatric dentists about the autogenous tooth transplantation technique, its success, its potential advantages and disadvantages and to report on three cases treated with autogenesis tooth transplantation.

  6. Sex Disparities in Arrest Outcomes for Domestic Violence

    Science.gov (United States)

    Hamilton, Melissa; Worthen, Meredith G. F.

    2011-01-01

    Domestic violence arrests have been historically focused on protecting women and children from abusive men. Arrest patterns continue to reflect this bias with more men arrested for domestic violence compared to women. Such potential gender variations in arrest patterns pave the way to the investigation of disparities by sex of the offender in…

  7. Dental patterning in the earliest sharks: Implications for tooth evolution.

    Science.gov (United States)

    Maisey, John G; Turner, Susan; Naylor, Gavin J P; Miller, Randall F

    2014-05-01

    Doliodus problematicus is the oldest known fossil shark-like fish with an almost intact dentition (Emsian, Lower Devonian, c. 397Ma). We provide a detailed description of the teeth and dentition in D. problematicus, based on tomographic analysis of NBMG 10127 (New Brunswick Museum, Canada). Comparisons with modern shark dentitions suggest that Doliodus was a ram-feeding predator with a dentition adapted to seizing and disabling prey. Doliodus provides several clues about the early evolution of the "shark-like" dentition in chondrichthyans and also raises new questions about the evolution of oral teeth in jawed vertebrates. As in modern sharks, teeth in Doliodus were replaced in a linguo-labial sequence within tooth families at fixed positions along the jaws (12-14 tooth families per jaw quadrant in NBMG 10127). Doliodus teeth were replaced much more slowly than in modern sharks. Nevertheless, its tooth formation was apparently as highly organized as in modern elasmobranchs, in which future tooth positions are indicated by synchronized expression of shh at fixed loci within the dental epithelium. Comparable dental arrays are absent in osteichthyans, placoderms, and many "acanthodians"; a "shark-like" dentition, therefore, may be a synapomorphy of chondrichthyans and gnathostomes such as Ptomacanthus. The upper anterior teeth in Doliodus were not attached to the palatoquadrates, but were instead supported by the ethmoid region of the prechordal basicranium, as in some other Paleozoic taxa (e.g., Triodus, Ptomacanthus). This suggests that the chondrichthyan dental lamina was originally associated with prechordal basicranial cartilage as well as jaw cartilage, and that the modern elasmobranch condition (in which the oral dentition is confined to the jaws) is phylogenetically advanced. Thus, oral tooth development in modern elasmobranchs does not provide a complete developmental model for chondrichthyans or gnathostomes.

  8. Mechanism of human tooth eruption

    DEFF Research Database (Denmark)

    Kjær, Inger

    2014-01-01

    Human eruption is a unique developmental process in the organism. The aetiology or the mechanism behind eruption has never been fully understood and the scientific literature in the field is extremely sparse. Human and animal tissues provide different possibilities for eruption analyses, briefly...... discussed in the introduction. Human studies, mainly clinical and radiological, have focused on normal eruption and gender differences. Why a tooth begins eruption and what enables it to move eruptively and later to end these eruptive movements is not known. Pathological eruption courses contribute......, and the ability of the periodontal ligament to adapt to eruptive movements. Animal studies and studies on normal and pathological eruption in humans can support and explain different aspects in the new theory. The eruption mechanism still needs elucidation and the paper recommends that future research on eruption...

  9. A METHOD OF DETERMINING THE ABILITY OF THE ARRESTER TO ABSORB ENERGY WITHOUT BREAKING THE HEAT BALANCE

    Directory of Open Access Journals (Sweden)

    S.Yu. Shevchenko

    2015-08-01

    Full Text Available Purpose.The aim of this study is to obtain a method for determining the capacity surge arrester nonlinear absorb energy without breaking the heat balance in modes of long-term application of operating voltage, which allows for analysis of their work in terms of violations as electricity. Methodology. For values of the energy passing through the arrester must be able to determine the current value for the voltage value in the area of leakage current-voltage characteristics. We have carried out calculations of the energy passing everywhere arrester for certain periods of time based on the current-voltage characteristics obtained experimentally. Analysis of the experimental current-voltage characteristics of resistors and literature led to the important conclusion that the dielectric properties of the ceramic varistor affect the value of active power losses in the arrester only when the active component of the leakage current is very small. This is confirmed by the characteristics of different classes of varistor voltage. This property of varistors and surge arresters shows the need to consider how the dielectric and conductive properties of the varistor ceramics in the analysis of work in the area of the arrester leakage current-voltage characteristic. These results demonstrate the need to clarify the mathematical model and the method for determining the energy dissipates in the area of the arrester leakage current CVC with their account. Results. The study, an improved mathematical model for calculating energy affects surge arrester during its working life. The study obtained the method, of evaluation capacity surge arrester, maintains heat balance throughout working life. Based on experimentally obtained current-voltage characteristic of the varistors is defined voltage at which surge arrester starts conducting active current. This allowed to receive specified mathematical model for calculating energy affects surge arrester and develop a method

  10. Recommendations to enable drug development for inherited neuropathies: Charcot-Marie-Tooth and Giant Axonal Neuropathy [v1; ref status: indexed, http://f1000r.es/33n

    Directory of Open Access Journals (Sweden)

    Lori Sames

    2014-04-01

    Full Text Available Approximately 1 in 2500 Americans suffer from Charcot-Marie-Tooth (CMT disease. The underlying disease mechanisms are unique in most forms of CMT, with many point mutations on various genes causing a toxic accumulation of misfolded proteins. Symptoms of the disease often present within the first two decades of life, with CMT1A patients having reduced compound muscle and sensory action potentials, slow nerve conduction velocities, sensory loss, progressive distal weakness, foot and hand deformities, decreased reflexes, bilateral foot drop and about 5% become wheelchair bound. In contrast, the ultra-rare disease Giant Axonal Neuropathy (GAN is frequently described as a recessively inherited condition that results in progressive nerve death. GAN usually appears in early childhood and progresses slowly as neuronal injury becomes more severe and leads to death in the second or third decade. There are currently no treatments for any of the forms of CMTs or GAN. We suggest that further clinical studies should analyse electrical impedance myography as an outcome measure for CMT. Further, additional quality of life (QoL assessments for these CMTs are required, and we need to identify GAN biomarkers as well as develop new genetic testing panels for both diseases. We propose that using the Global Registry of Inherited Neuropathy (GRIN could be useful for many of these studies. Patient advocacy groups and professional organizations (such as the Hereditary Neuropathy Foundation (HNF, Hannah's Hope Fund (HHF, The Neuropathy Association (TNA and the American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM can play a central role in educating clinicians and patients. Undertaking these studies will assist in the correct diagnosis of disease recruiting patients for clinical studies, and will ultimately improve the endpoints for clinical trials. By addressing obstacles that prevent industry investment in various forms of inherited neuropathies

  11. Recommendations to enable drug development for inherited neuropathies: Charcot-Marie-Tooth and Giant Axonal Neuropathy [v2; ref status: indexed, http://f1000r.es/3am

    Directory of Open Access Journals (Sweden)

    Lori Sames

    2014-04-01

    Full Text Available Approximately 1 in 2500 Americans suffer from Charcot-Marie-Tooth (CMT disease. The underlying disease mechanisms are unique in most forms of CMT, with many point mutations on various genes causing a toxic accumulation of misfolded proteins. Symptoms of the disease often present within the first two decades of life, with CMT1A patients having reduced compound muscle and sensory action potentials, slow nerve conduction velocities, sensory loss, progressive distal weakness, foot and hand deformities, decreased reflexes, bilateral foot drop and about 5% become wheelchair bound. In contrast, the ultra-rare disease Giant Axonal Neuropathy (GAN is frequently described as a recessively inherited condition that results in progressive nerve death. GAN usually appears in early childhood and progresses slowly as neuronal injury becomes more severe and leads to death in the second or third decade. There are currently no treatments for any of the forms of CMTs or GAN. We suggest that further clinical studies should analyse electrical impedance myography as an outcome measure for CMT. Further, additional quality of life (QoL assessments for these CMTs are required, and we need to identify GAN biomarkers as well as develop new genetic testing panels for both diseases. We propose that using the Global Registry of Inherited Neuropathy (GRIN could be useful for many of these studies. Patient advocacy groups and professional organizations (such as the Hereditary Neuropathy Foundation (HNF, Hannah's Hope Fund (HHF, The Neuropathy Association (TNA and the American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM can play a central role in educating clinicians and patients. Undertaking these studies will assist in the correct diagnosis of disease recruiting patients for clinical studies, and will ultimately improve the endpoints for clinical trials. By addressing obstacles that prevent industry investment in various forms of inherited neuropathies

  12. Spectroscopic investigations of carious tooth decay.

    Science.gov (United States)

    Thareja, R K; Sharma, A K; Shukla, Shobha

    2008-11-01

    We report on the elemental composition of healthy and infected part of human tooth using laser induced breakdown spectroscopy (LIBS). We have used prominent constituent transitions in laser-excited tooth to diagnose the state of the tooth. A nanosecond laser pulse (355nm, 5ns) was used as an ablating pulse and the sodium (3s2S-3p2P) at 588.99 and (3s2S-3p2P) at 589.99nm, strontium (5s21S-1s5P) at 460.55nm, and calcium (3d3D-4f 3F0) at 452.55nm transitions for spectroscopic analysis. The spectroscopic observations in conjunction with discriminate analysis showed that calcium attached to the hydroxyapatite structure of the tooth was affected severely at the infected part of the tooth. The position-time plots generated from two-dimensional (2D) images conclusively showed a decrease in calcium concentration in the infected region of the irradiated tooth. Using the technique, we could distinguish between the healthy and carious parts of the tooth with significant accuracy.

  13. Tooth Retained Implant: No More an Oxymoron

    Directory of Open Access Journals (Sweden)

    Divya Bhat

    2011-03-01

    Full Text Available Introduction: Periodontally af-fected teeth are treated in one of the two ways. (1 Tooth retention after periodontal surgery, in which the degree of regeneration achieved is unpredictable. (2 Tooth extrac-tion and implant placement. Implants have an osseointegrated surface which does not provide adequate shock absorption. Regeneration can be achieved by resecting the crown of the affected tooth and submerging the root. This technique has not had a clinical application so far as the tooth becomes difficult to restore. Placing an implant within the root can make the retained root restorable. At the same time, as the implant is placed within the root surface it achieves a periodontal integration which dampens occlusal forces better than osseointegration. Therefore, such a “tooth retained implant” may serve as an additional treatment option with significant benefits over tooth retention and implant placement alone. The hypothesis: Implants placed within retained roots have shown cementum deposition and attachment of periodontal ligament fibers over their surface. This periodontal attachment may be able to dam-pen forces better than in an osseointegrated implant. Moreover, since an implant is being placed, the crown of the tooth can be resected and submerged. This prevents epithelial migration, allows for the periodontal ligament cells to populate the wound and favors regeneration.Evaluation of the hypothesis: The technique of placing implants within cavities prepared in the root and then submerging them are simple for any practitioner placing implants routinely.

  14. A Case of Morgagni Hernia Resulting with Respiratory Arrest

    Directory of Open Access Journals (Sweden)

    Cavit Çöl

    2011-05-01

    Full Text Available Morgagni’s hernia is seen at a rate of 3-4% among all diaphragmatic hernias. It develops from a defect in the pleuroperitoneal membrane. Herniation of the omentum is seen most commonly, that of the colon frequently, and herniation of small bowel and stomach is seen rarely. When being examined due to anemia and dyspnea, a 53-year-old male patient suffered from a respiratory arrest and was hence intubated and placed under treatment at the intensive care unit. On radiological examination, a giant diaphragmatic hernia was observed bilaterally, more marked on the right side. On laparotomy, especially on the right side, the caecum, the ascending colon, the transverse colon, the appendix, the omentum and part of the small bowel was seen to be herniated. Primary diaphragmatic repair + right hemicolectomy + end-to-end ileo-transversostomy was performed. We have reported this case because it was a giant hernia which caused respiratory arrest.

  15. Gear transmission dynamic: Effects of tooth profile deviations and support flexibility

    OpenAIRE

    Fernández del Rincón, Alfonso; Iglesias Santamaría, Miguel; Juan de Luna, Ana Magdalena de; García Fernández, Pablo; Sancibrián Herrera, Ramón; Viadero Rueda, Fernando

    2014-01-01

    In this work a non-linear dynamic model of spur gear transmissions previously developed by the authors is extended to include both desired (relief) and undesired (manufacture errors) deviations in the tooth profile. The model uses a hybrid method for the calculation of meshing forces, which combines FE analysis and analytical formulation, so that it enables a very straightforward implementation of the tooth profile deviations. The model approach handles well non-linearity due to the variable ...

  16. Electron transport across a quantum wire embedding a saw-tooth superlattice

    Institute of Scientific and Technical Information of China (English)

    Chen Yuan-Ping; Yan Xiao-Hong; Lu Mao-Wang; Deng Yu-Xiang

    2004-01-01

    By developing the recursive Green function method, the transport properties through a quantum wire embedding a finite-length saw-tooth superlattice are studied in the presence of magnetic field. The effects of magnetic modulation and the geometric structures of the superlattice on transmission coefficient are discussed. It is shown that resonant electron gas. The transmission spectrum can be tailored to match requirements through adjusting the size of saw-tooth quantum dot and field strength.

  17. A comparative examination of odontogenic gene expression in both toothed and toothless amniotes

    OpenAIRE

    Alexis J. Lainoff; Moustakas-Verho, Jacqueline E.; Hu, Diane; Kallonen, Aki; Marcucio, Ralph S.; Hlusko, Leslea J

    2015-01-01

    A well-known tenet of murine tooth development is that BMP4 and FGF8 antagonistically initiate odontogenesis, but whether this tenet is conserved across amniotes is largely unexplored. Moreover, changes in BMP4-signaling have previously been implicated in evolutionary tooth loss in Aves. Here we demonstrate that Bmp4, Msx1, and Msx2 expression is limited proximally in the red-eared slider turtle (Trachemys scripta) mandible at stages equivalent to those at which odontogenesis is initiated in ...

  18. Resolution of Digitized Conjugate Tooth-Face Surface Based on the Theory of Digitized Conjugate Surfaces

    Institute of Scientific and Technical Information of China (English)

    XIAO Lai-yuan; LIAO Dao-xun; YI Chuan-yun

    2004-01-01

    According to the principle of meshing engagement and the theory of the digitized conjugate surface, this paper applies the software Conjugater-l. 0 that is developed by ourselves to compute, respectivcly, the digitized conjugate curved surfaces of the straight-tooth surface and drum-tooth surface,which will establish the theoretical and technical foundation for digitized engaging analysis, simulation, and digitized manufacturing technology of the diversified gears.

  19. Tooth resorption in cats: contribution of vitamin D and inflammation

    NARCIS (Netherlands)

    Vrieling, H.E.

    2010-01-01

    Tooth resorption in cats Tooth resorption affecting several teeth is a painful disease with a prevalence of up to 75% in household cats and is often accompanied by periodontitis. Tooth resorption is caused by an increased number and activity of tooth-resorbing odontoclasts, cells that share function

  20. Adhesion to tooth structure mediated by contemporary bonding systems.

    Science.gov (United States)

    Stangel, Ivan; Ellis, Thomas H; Sacher, Edward

    2007-07-01

    Given the enormity of the field of adhesion and the number of commercial products available, the discipline of modern adhesive dentistry can be daunting with respect to materials and techniques. This article organizes contemporary bonding practice and materials around an understanding of the fundamentals of adhesion to tooth structure. In providing this context, adhesive development, bonding systems, and their appropriate use are better understood. The end result is the better practice of adhesive dentistry.

  1. Women's perspectives on the context of violence and role of police in their intimate partner violence arrest experiences.

    Science.gov (United States)

    Li, Simiao; Levick, Ani; Eichman, Adelaide; Chang, Judy C

    2015-02-01

    Intimate partner violence (IPV) accounts for up to 50% of all calls to police. In an effort to standardize arrest criteria, mandatory arrest laws were established. It is unclear whether subsequent increased rates of female arrest are due to greater recognition of female IPV perpetrators or of women acting in self-defense. This study aims to understand the context and consequences of IPV-related arrest from perspectives of women arrested in a single metropolitan area. Semi-structured qualitative interviews were conducted with women arrested and court-ordered to attend IPV education groups at a women's shelter in the Northeast United States. Interviews addressed circumstances surrounding arrest, experience with past violence, and reasoning regarding use of partner violence. Two researchers independently coded transcripts and met to iteratively refine the code and review transcripts for themes. Eighteen women were interviewed. Major themes that emerged were as follows: (a) Women's use of violence occurred within the context of their own victimization; (b) the arrest included a complex interplay between subject, partner, and police; (c) women perceived police arrest decisions to be based on a limited understanding of context; and (d) women experienced both positive and negative consequences of arrest. Many relationships did not fall under the traditional victim/perpetrator construct. Rather, women's use of violence evolved, influenced by prior experiences with violence. More appropriate methods must be developed for making arrest decisions, guiding justice system responses, and developing interventions for couples experiencing IPV. Recognition that women's use of partner violence often represented either a retaliatory or self-defensive gesture within the context of prior victimization suggests that victims' interventions should not only focus on empowerment but also provide skills and strategies to avoid temptation to adopt aggression as a primary method of self-protection.

  2. Therapeutic Hypothermia and Out-of-Hospital Cardiac Arrest in a Child with Hypertrophic Obstructive Cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Nancy Spurkeland

    2015-01-01

    Full Text Available Neurologic outcomes following pediatric cardiac arrest are consistently poor. Early initiation of cardiopulmonary resuscitation has been shown to have positive effects on both survival to hospital discharge, and improved neurological outcomes after cardiac arrest. Additionally, the use of therapeutic hypothermia may improve survival in pediatric cardiac arrest patients admitted to the intensive care unit. We report a child with congenital hypertrophic obstructive cardiomyopathy and an out-of-hospital cardiac arrest, in whom the early initiation of effective prolonged cardiopulmonary resuscitation and subsequent administration of therapeutic hypothermia contributed to a positive outcome with no gross neurologic sequelae. Continuing efforts should be made to promote and employ high-quality cardiopulmonary resuscitation, which likely contributed to the positive outcome of this case. Further research will be necessary to develop and solidify national guidelines for the implementation of therapeutic hypothermia in selected subpopulations of children with OHCA.

  3. Parameter identification of ZnO surge arrester models based on genetic algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Bayadi, Abdelhafid [Laboratoire d' Automatique de Setif, Departement d' Electrotechnique, Faculte des Sciences de l' Ingenieur, Universite Ferhat ABBAS de Setif, Route de Bejaia Setif 19000 (Algeria)

    2008-07-15

    The correct and adequate modelling of ZnO surge arresters characteristics is very important for insulation coordination studies and systems reliability. In this context many researchers addressed considerable efforts to the development of surge arresters models to reproduce the dynamic characteristics observed in their behaviour when subjected to fast front impulse currents. The difficulties with these models reside essentially in the calculation and the adjustment of their parameters. This paper proposes a new technique based on genetic algorithm to obtain the best possible series of parameter values of ZnO surge arresters models. The validity of the predicted parameters is then checked by comparing the predicted results with the experimental results available in the literature. Using the ATP-EMTP package, an application of the arrester model on network system studies is presented and discussed. (author)

  4. Abnormal tooth development in a sea lamprey

    Science.gov (United States)

    Manion, Patrick J.; Hanson, Lee H.

    1977-01-01

    Sea lampreys en route to their spawning grounds have been captured at mechanical or electrical structures that have been in operation for 1 to 27 spawning seasons (1949-75) on some 167 tributaries of the upper Great Lakes; more than 750,000 were taken in 1949-70 (Smith 1971). Among these lampreys (all of which were routinely examined at the time of capture) was one female (length, 434 mm; weight, 130 g) with markedly underdeveloped teeth. It was captured in May 1968 at an electrical barrier in the Ocqueoc River, a Michigan tributary of Lake Huron

  5. Impacted supernumerary tooth in coronoid process: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Park, Won Se; Lee, Je Ho; Park, Hyok; Jung, Ho Gul; Kim, Kee Deog [Yonsei University College of Dentistry, Seoul (Korea, Republic of)

    2010-06-15

    Impaction of tooth is a situation in which an unerupted tooth is wedged against another tooth or teeth or otherwise located so that it cannot erupt normally. The supernumerary tooth is also called as hyperdontia and defined as the condition of having additional tooth to the regular number of teeth. The most common supernumerary tooth is a mesiodens, which is a mal-formed, peg-like tooth that occurs between the maxillary incisors. The supernumerary tooth is commonly impacted but they are frequently impacted on maxilla. Ectopic impaction of supernumerary tooth on mandibular condyle, coronoid process, ascending ramus, and pterygomandibular space is very rare condition. In this case, we report a case of impacted supernumerary tooth on mandibular sigmoid notch without definite pathologic change.

  6. Critical appraisal. In-office tooth whitening: pulpal effects and tooth sensitivity issues.

    Science.gov (United States)

    Kwon, So Ran; Swift, Edward J

    2014-01-01

    In-office bleaching is an effective method for whitening teeth.Tooth sensitivity associated with in-office whitening is reversible and may range from mild to considerable. The incidence and severity of tooth sensitivity can be reduced by pretreatment with a desensitizer such as potassium nitrate. Histologic studies and clinical studies on long-term pulpal effects are lacking to definitively support the safety of in-office tooth whitening. Future studies on the etiology of tooth sensitivity related to whitening might greatly improve the means of preventing and managing this side effect.

  7. Charcot-Marie-Tooth and Related Diseases

    Science.gov (United States)

    ... of France, and Howard Henry Tooth of the United Kingdom. Although most people have never heard of CMT, ... CMT provided by patients and families. (See http://neurology.med. wayne.edu/neurogenetics/na_database. php.) MDA ...

  8. Endodontic therapy or single tooth implant? A systematic review.

    Science.gov (United States)

    Torabinejad, Mahmoud; Lozada, Jaime; Puterman, Israel; White, Shane N

    2008-06-01

    Should a tooth with pulpal involvement be saved through endodontic therapy, or extracted and replaced with a single tooth implant? Within the limitations of the existing literature, this systematic review of treatment outcomes found that initial endodontic treatment had a high long-term survival rate, equivalent to replacement of a missing tooth with an implant-supported restoration. Single tooth implants should be considered as the first treatment option for patients requiring extraction and tooth replacement.

  9. Hard tissue regeneration capacity of apical pulp derived cells (APDCs) from human tooth with immature apex.

    Science.gov (United States)

    Abe, Shigehiro; Yamaguchi, Satoshi; Watanabe, Akihiko; Hamada, Keiichi; Amagasa, Teruo

    2008-06-20

    Recent studies indicate that dental pulp is a new source of adult stem cells. The human tooth with an immature apex is a developing organ, and the apical pulp of this tooth may contain a variety of progenitor/stem cells, which participate in root formation. We investigated the hard tissue regeneration potential of apical pulp derived cells (APDCs) from human tooth with an immature apex. APDCs cultured with a mineralization-promoting medium showed alkaline phosphatase activity in porous hydroxyapatite (HA) scaffolds. The composites of APDCs and HA were implanted subcutaneously in immunocompromised rats and harvested at 12 weeks after implantation. In histological analysis, the APDCs/HA composites exhibited bone- and dentine-like mineralized tissues in the pore areas of HA. This study suggests that the human tooth with an immature apex is an effective source of cells for hard tissue regeneration.

  10. Detection and Diagnosis of Gear Fault By the Single Gear Tooth Analysis Technique

    Institute of Scientific and Technical Information of China (English)

    MENG Tao; LIAO Ming-fu

    2003-01-01

    This paper presents a procedure of single gear tooth analysis for early detection and diagnosis of gear faults. The objective of this procedure is to develop a method for more sensitive detection of the incipient faults and locating the faults in the gear. The main idea of the single gear tooth analysis is that the vibration signals collected with a high sampling rate are divided into a number of segments with the same time interval. The number of signal segments is equal to that of the gear teeth. The analysis of individual segments reveals more sensitively the changes of the vibration signals in both time and frequency domain caused by gear faults. In addition, the location of a failed tooth can be indicated in terms of the position of the segment that deviates from the normal segments. An experimental investigation verified the advantages of the single gear tooth analysis.

  11. Hipotermia terapêutica em pacientes pós-parada cardiorrespiratória: mecanismos de ação e desenvolvimento de protocolo assistencial Mild therapeutic hypothermia after cardiac arrest: mechanism of action and protocol development

    Directory of Open Access Journals (Sweden)

    Tatiana Helena Rech

    2010-06-01

    Full Text Available A parada cardiorrespiratória é um evento de alta mortalidade. A isquemia cerebral difusa relacionada ao hipofluxo cerebral frequentemente leva à injúria neurológica grave e ao desenvolvimento de estado vegetativo persistente. A hipotermia terapêutica representa um importante avanço no tratamento da encefalopatia anóxica pós-parada cardíaca. Seus efeitos neuroprotetores têm sido amplamente demonstrados em várias situações de isquemia neuronal. Apesar de ser um procedimento associado com redução de mortalidade nesses pacientes, a hipotermia ainda é um tratamento subutilizado no manejo da síndrome pós-ressuscitação. Nosso objetivo é revisar aspectos referentes aos mecanismos de ação da hipotermia e seus efeitos em pacientes críticos reanimados pós- parada cardiorrespiratória e propor um protocolo assistencial simples, que possa ser implantado em qualquer unidade de terapia intensiva.Cardiac arrest is a high mortality event and the associated brain ischemia frequently causes severe neurological damage and persistent vegetative state. Therapeutic hypothermia is an important tool for the treatment of post-anoxic coma after cardiopulmonary resuscitation. It has been shown to reduce mortality and to improve neurological outcomes after cardiac arrest. Nevertheless, hypothermia is underused in critical care units. This manuscript aims to review the hypothermia mechanism of action in cardiac arrest survivors and to propose a simple protocol, feasible to be implemented in any critical care unit.

  12. Bone marrow combined with dental bud cells promotes tooth regeneration in miniature pig model.

    Science.gov (United States)

    Kuo, Tzong-Fu; Lin, Hsin-Chi; Yang, Kai-Chiang; Lin, Feng-Huei; Chen, Min-Huey; Wu, Chang-Chin; Chang, Hao-Hueng

    2011-02-01

    Growth factors and morphogens secreted by bone marrow mesenchymal stem cells (BMSCs) of bone marrow fluid may promote tooth regeneration. Accordingly, a tissue engineering approach was utilized to develop an economical strategy for obtaining the growth factors and morphogens from BMSCs. Unerupted second molar tooth buds harvested from miniature pigs were cultured in vitro to obtain dental bud cells (DBCs). Bone marrow fluid, which contains BMSCs, was collected from the porcine mandible before operation. DBCs suspended in bone marrow fluid were seeded into a gelatin/chondoitin-6-sulfate/hyaluronan tri-copolymer scaffold (GCHT scaffold). The DBCs/bone marrow fluid/GCHT scaffold was autografted into the original alveolar sockets of the pigs. Radiographic and histological examinations were applied to identify the structure of regenerated tooth at 40 weeks postimplantation. The present results showed that one pig developed a complete tooth with crown, root, pulp, enamel, dentin, odontoblast, cementum, blood vessel, and periodontal ligament in indiscriminate shape. Three animals had an unerupted tooth that expressed dentin matrix protein-1, vascular endothelial growth factor, and osteopontin; and two other pigs also had dental-like structure with dentin tubules. This study reveals that DBCs adding bone marrow fluid and a suitable scaffold can promote the tooth regeneration in autogenic cell transplantation.

  13. Site-specific function and regulation of Osterix in tooth root formation

    Science.gov (United States)

    He, Y. D.; Sui, B. D.; Li, M.; Huang, J.; Chen, S.; Wu, L. A.

    2016-01-01

    Congenital diseases of tooth roots, in terms of developmental abnormalities of short and thin root phenotypes, can lead to loss of teeth. A more complete understanding of the genetic molecular pathways and biological processes controlling tooth root formation is required. Recent studies have revealed that Osterix (Osx), a key mesenchymal transcriptional factor participating in both the processes of osteogenesis and odontogenesis, plays a vital role underlying the mechanisms of developmental differences between root and crown. During tooth development, Osx expression has been identified from late embryonic to postnatal stages when the tooth root develops, particularly in odontoblasts and cementoblasts to promote their differentiation and mineralization. Furthermore, the site-specific function of Osx in tooth root formation has been confirmed, because odontoblastic Osx-conditional knockout mice demonstrate primarily short and thin root phenotypes with no apparent abnormalities in the crown (Journal of Bone and Mineral Research 30, 2014 and 742, Journal of Dental Research 94, 2015 and 430). These findings suggest that Osx functions to promote odontoblast and cementoblast differentiation and root elongation only in root, but not in crown formation. Mechanistic research shows regulatory networks of Osx expression, which can be controlled through manipulating the epithelial BMP signalling, mesenchymal Runx2 expression and cellular phosphorylation levels, indicating feasible routes of promoting Osx expression postnatally (Journal of Cellular Biochemistry 114, 2013 and 975). In this regard, a promising approach might be available to regenerate the congenitally diseased root and that regenerative therapy would be the best choice for patients with developmental tooth diseases. PMID:26599722

  14. Local stresses, dyke arrest and surface deformation in volcanic edificesand rift zones

    Directory of Open Access Journals (Sweden)

    L. S. Brenner

    2004-06-01

    Full Text Available Field studies indicate that nearly all eruptions in volcanic edifices and rift zones are supplied with magma through fractures (dykes that are opened by magmatic overpressure. While (inferred dyke injections are frequent during unrest periods, volcanic eruptions are, in comparison, infrequent, suggesting that most dykes become arrested at certain depths in the crust, in agreement with field studies. The frequency of dyke arrest can be partly explained by the numerical models presented here which indicate that volcanic edifices and rift zones consisting of rocks of contrasting mechanical properties, such as soft pyroclastic layers and stiff lava flows, commonly develop local stress fields that encourage dyke arrest. During unrest, surface deformation studies are routinely used to infer the geometries of arrested dykes, and some models (using homogeneous, isotropic half-spaces infer large grabens to be induced by such dykes. Our results, however, show that the dyke-tip tensile stresses are normally much greater than the induced surface stresses, making it difficult to explain how a dyke can induce surface stresses in excess of the tensile (or shear strength while the same strength is not exceeded at the (arrested dyke tip. Also, arrested dyke tips in eroded or active rift zones are normally not associated with dyke-induced grabens or normal faults, and some dykes arrested within a few metres of the surface do not generate faults or grabens. The numerical models show that abrupt changes in Young's moduli(stiffnesses, layers with relatively high dyke-normal compressive stresses (stress barriers, and weak horizontal contacts may make the dyke-induced surface tensile stresses too small for significant fault or graben formation to occur in rift zones or volcanic edifices. Also, these small surface stresses may have no simple relation to the dyke geometry or the depth to its tip. Thus, for a layered crust with weak contacts, straightforward

  15. Full mouth rehabilitation with maxillary tooth supported and mandibular tooth and implant supported combination prostheses: a 4-year case report.

    Science.gov (United States)

    Pramod Kumar, A V; Vinni, T K; Mahesh, Mehul R

    2012-06-01

    The primary objectives of successful prosthetic rehabilitation are to provide function, esthetics and comfort to the patient. Combination prosthesis is one which is supported by both natural teeth and implant. The periodontal ligament and osseointegrated interface distribute force differently to the supporting bone. Therefore problems can develop when tooth and implants are combined in the same prosthesis. However, clinicians can apply biomechanical principles, to negate the deleterious leverages exerted by the fixed prosthesis by using non rigid components and to equalize the stress applied by the prosthesis on implant and teeth. A case of partially edentulous situation was rehabilitated successfully with a combination of prostheses. Maxillary arch was restored to function with crowns, fixed dental prosthesis and with an extra coronal castable attachment prosthesis and the mandibular arch with a combination of tooth and implant supported attachment prosthesis. The clinical and laboratory steps for the fabrication of these prostheses are explained in this report.

  16. A new on-line leakage current monitoring system of ZnO surge arresters

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bok-Hee [Research Center for Next-Generation High Voltage and Power Technology, Inha University, 253 Yonghyun-dong, Nam-ku, Incheon 402-751 (Korea, Republic of)]. E-mail: bhlee@inha.ac.kr; Kang, Sung-Man [Research Center for Next-Generation High Voltage and Power Technology, Inha University, 253 Yonghyun-dong, Nam-ku, Incheon 402-751 (Korea, Republic of)

    2005-05-15

    This paper presents a new on-line leakage current monitoring system of zinc oxide (ZnO) surge arresters. To effectively diagnose the deterioration of ZnO surge arresters, a new algorithm and on-line leakage current detection device, which uses the time-delay addition method, for discriminating the resistive and capacitive currents was developed to use in the aging test and durability evaluation for ZnO arrester blocks. A computer-based measurement system of the resistive leakage current, the on-line monitoring device can detect accurately the leakage currents flowing through ZnO surge arresters for power frequency ac applied voltages. The proposed on-line leakage current monitoring device of ZnO surge arresters is more highly sensitive and gives more linear response than the existing devices using the detection method of the third harmonic leakage currents. Therefore, the proposed leakage current monitoring device can be useful for predicting the defects and performance deterioration of ZnO surge arresters in power system applications.

  17. A possible etiology for the dilaceration and flexion of permanent tooth roots relative to bone remodeling gradients in alveolar bone

    Directory of Open Access Journals (Sweden)

    Richard G Standerwick

    2014-01-01

    Full Text Available Introduction: Trauma, altered tooth germ position and delayed tooth eruption have been hypothesized as possible causes of tooth root dilacerations and flexion, however these anatomical variations appear more commonly associated with posterior teeth and absence of traumatic history. The Hypothesis: Postulated is that tooth root dilaceration or flexion may be a result of tooth root sheath displacement due to gradients of bone remodeling present within alveolar bone. Evaluation of the Hypothesis: Alveolar bone displays bone remodeling gradients between coronal, apical and basal sections which affect bone plasticity. As a tooth is erupting or experiences delayed eruption, there are other relative dento-skeletal alterations occurring, such as the mesial drift of the dentition and transverse growth of the maxilla. It is plausible that during the physiologic and growth related alteration of the alveolar and basal bones, portions of developing tooth could be found within one or more of the plasticity zones, contributing to alteration of the root sheath and tooth root dilaceration.

  18. Juvenile Arrests, 2007. Juvenile Justice Bulletin

    Science.gov (United States)

    Puzzanchera, Charles

    2009-01-01

    This Bulletin summarizes 2007 juvenile crime and arrest data reported by local law enforcement agencies across the country and cited in the FBI report, "Crime in the United States 2007." The Bulletin describes the extent and nature of juvenile crime that comes to the attention of the justice system. It serves as a baseline for comparison for…

  19. Platelet-rich fibrin-mediated revitalization of immature necrotic tooth

    Directory of Open Access Journals (Sweden)

    Navin Mishra

    2013-01-01

    Full Text Available Contemporary studies have shown that the regeneration of tissues and root elongation is possible in necrotic immature permanent teeth. The purpose of this case report is to add a new vista in regenerative endodontic therapy by using platelet rich fibrin for revitalization of immature non vital tooth. An 11year old boy with the history of trauma was diagnosed with the pulpal necrosis and symptomatic apical periodontitis in tooth #21. Intra oral periapical radiograph showed open apex and associated immature supernumerary tooth with respect to tooth #21. Access preparation and minimal instrumentation was done to remove necrotic debris under copious irrigation with 2.5% sodium hypochlorite. Triple antibiotic paste was packed in the canal for four weeks. During second visit, 5 mL of whole blood was drawn from the medial cubital vein of the patient and blood was then subjected to centrifugation at 2400 rpm for 12 minutes for the preparation of Platelet rich fibrin (PRF utilizing Choukroun′s method. Triple antibiotic paste was removed and canal was dried. PRF clot was pushed to the apical region of tooth #21 using hand pluggers. Three milimetres of Mineral trioxide (MTA was placed in cervical part of the root canal and permanent restoration was done three days later. Clinical examination at 6 and 12 months revealed no sensitivity to percussion and palpation in tooth #21and it responded positively to both electric pulp and cold tests. Radiographic examination showed resolution of periapical rarefaction, further root development and apical closure of the tooth #21 and its associated supernumerary tooth. On the basis of successful outcome of the present case it can be stated that PRF clot may serve as a scaffold for regeneration of necrotic immature teeth.

  20. Family income and tooth decay in US children: does the association change with age?

    Science.gov (United States)

    Bernabé, E; Delgado-Angulo, E K; Murasko, J E; Marcenes, W

    2012-01-01

    This study explored whether the association of family income with tooth decay changes with age among children in the United States. A second objective was to explore the role of access to dental health care services in explaining the interrelationships between family income, child age and tooth decay. Data from 7,491 2- to 15-year-old children who participated in the 1999-2004 National and Health and Nutrition Examination Survey were analyzed. The association of family income with the prevalence of tooth decay in primary, permanent and primary or permanent teeth was first estimated in logistic regression models with all children, and then, separately in four age groups that reflect the development of the dentition (2-5, 6-8, 9-11 and 12-15 years, respectively). Findings showed that the income gradient in tooth decay attenuated significantly in 9- to 11-year-olds only to re-emerge in 12- to 15-year-olds. The age profile of the income gradient in tooth decay was not accounted for by a diverse set of family and child characteristics. This is the first study providing some evidence for age variations in the income gradient in tooth decay among children in the United States.

  1. The role of chromogenic bacteria in external tooth discoloration in children

    Directory of Open Access Journals (Sweden)

    Zuhal Kırzıoğlu

    2016-08-01

    Full Text Available Tooth discoloration can cause social and psychological problems and lead to loss of self-confidence in children. Concerns of parents and children on appearance and esthetics increase the importance of dental esthetic treatments in children. External tooth discoloration in children can be seen in both the primary and the permanent teeth. Poor oral hygiene, use of iron preparations and chromogenic bacteria are among the etiology of external tooth discoloration. Chromogenic bacteria can cause black/brown, green, orange or blue discolorations on the tooth surfaces of children. For clinicians, most interesting external tooth discoloration in children has been the black discoloration, which is more frequently observed compared to the other types. Most of the studies also have focused on the chromogenic bacteria associated with black discolorations, and the data concerning other types of discoloration are limited. Our knowledge on the existing chromogenic bacterial mechanisms is increasing by the developing microbiological diagnostic procedures, and new species associated with discoloration are becoming recognized. Still, studies dealing with the mechanisms of the chromogenic bacteria leading to discoloration are insufficient in the accessible sources. The objective of this article is to emphasize the role of the chromogenic bacteria in external tooth discoloration in children, to review precautions that can be taken to prevent discoloration, and current treatment methods, and to contribute to the current knowledge of the clinicians on this subject.

  2. Cardiac arrest: comparison of paramedic and conventional ambulance services.

    OpenAIRE

    1983-01-01

    A prospective study conducted in the Greater Vancouver area compared survival rates in prehospital cardiac arrest managed by an advanced life support (paramedic) service with those in cardiac arrest managed by conventional ambulance service. Management by the paramedic service was associated with higher survival rates for patients found in cardiac arrest but not for patients who suffered the arrest while the ambulance was present. Cardiopulmonary resuscitation by bystanders was associated wit...

  3. The role of APCDD1 in epithelial rearrangement in tooth morphogenesis.

    Science.gov (United States)

    Neupane, Sanjiv; Sohn, Wern-Joo; Gwon, Gi-Jeong; Kim, Ki-Rim; Lee, Sanggyu; An, Chang-Hyeon; Suh, Jo-Young; Shin, Hong-In; Yamamoto, Hitoshi; Cho, Sung-Won; Lee, Youngkyun; Kim, Jae-Young

    2015-10-01

    Adenomatosis polyposis coli downregulated 1 (APCDD1), a negative regulator of Wnt signaling, was examined to understand detailed mechanisms underlying Wnt signaling tooth development. In situ hybridization showed that Apcdd1 was expressed in the condensed mesenchyme at the bud stage, and in the inner enamel epithelium (IEE), including enamel knot (EK) at the cap stage. In vitro organ cultivation by using Apcdd1 antisense oligodeoxynucleotides was performed at E13.5 for 2 days to define the developmental functions of APCDD1 during tooth development. Analysis of histogenesis and cellular events such as cell adhesion, proliferation, apoptosis and epithelial rearrangement after Apcdd1 knockdown showed altered morphogenesis of the tooth germ with decreased cell proliferation and altered localization of cell adhesion molecules. Actin filament staining and 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) labeling of IEE cells showed that Apcdd1 knockdown enhanced epithelial rearrangement in the IEE and EK. To understand the precise signaling regulations of Apcdd1, we evaluated the altered expression patterns of signaling molecules, related with Wnt and enamel knot signalings using RT-qPCR. Tooth germs at cap stage were transplanted into the kidney capsules and were allowed to develop into calcified teeth for 3 weeks. Apcdd1 knockdown increased the number of ectopic cusps on the mesial side of the tooth. Our results suggested that APCDD1 modulates the gene expression of Wnt- and EK-related signaling molecules at the cap stage of tooth development, and is involved in tooth cusp patterning by modulating the epithelial rearrangement in the IEE.

  4. Controlled Deposition of HAp Mimicking Tooth Enamel

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Chemical compositions and microsturcture of mature human tooth enamel were investigated by XRD , FTIR and SEM to further understand the characteristics of tooth enamel. In order to obtain apatite crystals chemically and structurally similar to those in tooth enamel, biomimetic way was employed. Selfassembled monolyers terminated with-SO3 H groups were used as deposition substrates and 1.5 SBF ( the concentrations of Ca2+ and PO43- ions 1.5 times than those in simulated body fluid ) with and without 5 ppm F- were used as soaking medium. The XRD and FTIR results showed that both the deposited fluoride-substituted hydroxyapatite( F-HAp ) crystals in 1.5 SBF with F- and hydroxyapatite ( HAp ) crystals in 1.5 SBF were carbonate-containing, mimicking human tooth enamel in chemical compositions. The SEM photos showed that needle-like F-HAp crystals bad large aspect ratios and grew in bundles, which were similar to the crystals in human tooth enamel.The results provide available information on dental restoration.

  5. The evolution of dinosaur tooth enamel microstructure.

    Science.gov (United States)

    Hwang, Sunny H

    2011-02-01

    The evolution of tooth enamel microstructure in both extinct and extant mammalian groups has been extensively documented, but is poorly known in reptiles, including dinosaurs. Previous intensive sampling of dinosaur tooth enamel microstructure revealed that: (1) the three-dimensional arrangement of enamel types and features within a tooth-the schmelzmuster-is most useful in diagnosing dinosaur clades at or around the family level; (2) enamel microstructure complexity is correlated with tooth morphology complexity and not necessarily with phylogenetic position; and (3) there is a large amount of homoplasy within Theropoda but much less within Ornithischia. In this study, the examination of the enamel microstructure of 28 additional dinosaur taxa fills in taxonomic gaps of previous studies and reinforces the aforementioned conclusions. Additionally, these new specimens reveal that within clades such as Sauropodomorpha, Neotheropoda, and Euornithopoda, the more basal taxa have simpler enamel that is a precursor to the more complex enamel of more derived taxa and that schmelzmusters evolve in a stepwise fashion. In the particularly well-sampled clade of Euornithopoda, correlations between the evolution of dental and enamel characters could be drawn. The ancestral schmelzmuster for Genasauria remains ambiguous due to the dearth of basal ornithischian teeth available for study. These new specimens provide new insights into the evolution of tooth enamel microstructure in dinosaurs, emphasizing the importance of thorough sampling within broadly inclusive clades, especially among their more basal members.

  6. Modes of induced cardiac arrest: hyperkalemia and hypocalcemia - Literature review

    OpenAIRE

    Oliveira,Marcos Aurélio Barboza de; Brandi, Antônio Carlos; dos Santos, Carlos Alberto; Botelho, Paulo Henrique Husseini; Cortez, José Luis Lasso; Braile, Domingo Marcolino

    2014-01-01

    The entry of sodium and calcium play a key effect on myocyte subjected to cardiac arrest by hyperkalemia. They cause cell swelling, acidosis, consumption of adenosine triphosphate and trigger programmed cell death. Cardiac arrest caused by hypocalcemia maintains intracellular adenosine triphosphate levels, improves diastolic performance and reduces oxygen consumption, which can be translated into better protection to myocyte injury induced by cardiac arrest.

  7. Adulthood animal abuse among men arrested for domestic violence.

    Science.gov (United States)

    Febres, Jeniimarie; Brasfield, Hope; Shorey, Ryan C; Elmquist, Joanna; Ninnemann, Andrew; Schonbrun, Yael C; Temple, Jeff R; Recupero, Patricia R; Stuart, Gregory L

    2014-09-01

    Learning more about intimate partner violence (IPV), perpetrators could aid the development of more effective treatments. The prevalence of adulthood animal abuse (AAA) perpetration and its association with IPV perpetration, antisociality, and alcohol use in 307 men arrested for domestic violence were examined. Forty-one percent (n = 125) of the men committed at least one act of animal abuse since the age of 18, in contrast to the 1.5% prevalence rate reported by men in the general population. Controlling for antisociality and alcohol use, AAA showed a trend toward a significant association with physical and severe psychological IPV perpetration.

  8. Escaping growth arrest in cancer

    NARCIS (Netherlands)

    Kortlever, R.M.

    2008-01-01

    We now have a general idea of which genes and cellular pathways are central in cancer development: uncontrolled growth governs establishment and spread of the disease. Nevertheless, to fully appreciate the consequences of the interplay of driver mutations in this genetic disease it is imperative we

  9. Effect of drugs on orthodontic tooth movement

    Directory of Open Access Journals (Sweden)

    Siti Sarah Aulia Amrullah

    2016-06-01

    Full Text Available Orthodontic tooth movement is basically a biological response to mechanical forces given to the teeth in orthodontic treatment, which involving the periodontal tissue and alveolar bone, resulting in the release of numerous substances from the dental tissues and surrounding structure. Remodeling changes in periodontal tissues are considered to be essential in effecting orthodontic tooth movement which is the base of orthodontic correction. Molecules produced in various diseased tissues or drugs and nutrients consumed regularly by patients, can influence mechanically stressed periodontal tissue through the circulation and interact with target cell combination of which may be inhibitory, additive or synergize. Medications might have an important influence on the rate of tooth movement, and information on their consumption is essential to adequately discuss treatment planning with patients. Therefore it is imperative to the practitioners being in medical profession, must pay close attention to the drug consumption history of every patient before and during the course of treatment.

  10. Maxillary tooth displacement in the infratemporal fossa

    Directory of Open Access Journals (Sweden)

    Korosh Roshanghias

    2016-01-01

    Full Text Available Wisdom tooth operations are sometimes accompanied by complications. This case report shows complications during upper jaw third molar removal. Expectable problems during oral surgery should be planned to be solved in advance. Displacement of the third molar during oral surgeries as a considerable complication is rarely discussed scientifically. A good design of flap, adequate power for extraction, and clear view on the surgical field are crucial. Three-dimensional radiographic diagnostics in terms of cone beam computed tomography is helpful after tooth displacement into the infratemporal fossa.

  11. Ectopic tooth in maxillary sinus: Case series.

    Science.gov (United States)

    Ramanojam, Shandilya; Halli, Rajshekhar; Hebbale, Manjula; Bhardwaj, Smita

    2013-01-01

    Ectopic eruption of a tooth within the dentate region of the jaws is often noticed in clinical practice and is well documented in the literature. But the ectopic eruption into the non dentate region is rare and scantly documented. The maxillary sinus is one such a non dentate region, apart from nasal septum, mandibular condyle, coronoid process and the palate, to accommodate such ectopic eruptions of teeth. Due to its rarity and lack of consensus over its management, the incidence deserves to be added to the literature and discussed. Early surgical intervention for removal of ectopic tooth along with enucleation of the associated cyst, if any, is the treatment of choice.

  12. 21 CFR 872.3200 - Resin tooth bonding agent.

    Science.gov (United States)

    2010-04-01

    .... A resin tooth bonding agent is a device material, such as methylmethacrylate, intended to be painted on the interior of a prepared cavity of a tooth to improve retention of a restoration, such as...

  13. 3D analysis of craniofacial growth and tooth eruption

    DEFF Research Database (Denmark)

    Kreiborg, Sven

    The 9th International Congress on Cleft Palate and Related Craniofacial Anomalies, 3D analysis, craniofacial growth, tooth eruption......The 9th International Congress on Cleft Palate and Related Craniofacial Anomalies, 3D analysis, craniofacial growth, tooth eruption...

  14. 小鼠牙胚发育过程中釉原蛋白和釉蛋白的表达特征%Expression patterns of amelogenin and enamelin in developing mouse tooth germs

    Institute of Scientific and Technical Information of China (English)

    田华; 吕平; 周春燕; 高学军

    2012-01-01

    目的 观察釉原蛋白和釉蛋白在小鼠牙胚发育中的表达特征,进一步揭示釉原蛋白和釉蛋白的生物学特性.方法 分别制备出生后第1、3、7和14天小鼠下颌第一磨牙牙胚切片,采用免疫组织化学和反转录聚合酶链反应法检测釉原蛋白和釉蛋白的组织学定位和基因转录表达水平.结果 釉原蛋白表达于分泌期成釉细胞的胞质和釉质基质全层,在新生小鼠牙胚成牙本质细胞中有一过性表达;釉蛋白表达于分泌期釉质基质中,在成釉质细胞突边缘和釉质基质深层呈强阳性表达,釉原蛋白和釉蛋白在矿化成熟的釉质中均未见表达.釉原蛋白和釉蛋白在出生后第7天mRNA表达量的相对值分别为0.813±0.085和0.799±0.064,显著高于其他时间的表达水平(P<0.05).结论 釉原蛋白和釉蛋白主要由分泌期成釉细胞合成并分泌到釉质基质中,其表达具有高度的时空特异性,提示它们在釉质形成和生物矿化中有重要的作用.%Objective To invesitgate the expression patterns of amelogenin and enamelin in the developing tooth germs.Methods Mandible sections of postnatal day 1,3,7 and 14 mouse were prepared,immunohistochemical analysis and reverse transcriptase polymerase chain reaction(RT-PCR) were performed to detect the expression patterns of amelogenin and enamelin in mandibular first molars. Results Amelogenin was observed in the cytoplasm of secretory ameloblasts and the whole enamel matrix layer.It was also transiently expressed in the odontoblasts of postnatal day 1 molars.Enamelin proteins were observed in the enamel layer deposited by secretory ameloblasts,especially intense beneath the ameloblast process and dentino-enamel junction.The mRNA levels of both amelogenin and enamelin were highest on postnatal day 7(the ratio to glyceraldehyde phosphate dehydrogenase of amelogenin and enamelin:0.813 ± 0.085 and 0.799 ± 0.064,respectively,P < 0.05 ).Conclusions Amelogenin

  15. Nuclear reactor melt arrest and coolability device

    Energy Technology Data Exchange (ETDEWEB)

    Theofanous, Theo G.; Dinh, Nam Truc; Wachowiak, Richard M.

    2016-06-14

    Example embodiments provide a Basemat-Internal Melt Arrest and Coolability device (BiMAC) that offers improved spatial and mechanical characteristics for use in damage prevention and risk mitigation in accident scenarios. Example embodiments may include a BiMAC having an inclination of less than 10-degrees from the basemat floor and/or coolant channels of less than 4 inches in diameter, while maintaining minimum safety margins required by the Nuclear Regulatory Commission.

  16. Rheology and structural arrest of casein suspensions

    OpenAIRE

    Dahbi, Louisa; Alexander, M.; Trappe, Véronique; Dhont, J. K. G.; Schurtenberger, Peter

    2010-01-01

    The rheology of milk powder suspensions is investigated up to very high concentrations, where structural arrest occurs. The main component of the milk powder investigated is casein, so that the suspensions can be regarded as casein suspensions. Four concentration regimes are identified. For effective casein volume fractions less than 0.54 the concentration dependence of the zero-shear viscosity is similar to that of hard-sphere suspensions. However, due to the elastic deformation of the casei...

  17. Aerodynamically generated noise by lightning arrester

    Directory of Open Access Journals (Sweden)

    Váchová J.

    2007-10-01

    Full Text Available This paper presents the general solution of aerodynamically generated noise by lightning arrester. Governing equations are presented in form of Lighthill acoustic analogy, as embodied in the Ffowcs Williams-Hawkings (FW-H equation. This equation is based on conservation laws of fluid mechanics rather than on the wave equation. Thus, the FW-H equation is valid even if the integration surface is in nonlinear region. That’s why the FWH method is superior in aeroacoustics. The FW-H method is implemented in program Fluent and the numerical solution is acquired by Fluent code.The general solution of acoustic signal generated by lightning arrester is shown and the results in form of acoustic pressure and frequency spectrum are presented. The verification of accuracy was made by evaluation of Strouhal number. A comparison of Strouhal number for circumfluence of a cylinder and the lightning arrester was done, because the experimental data for cylinder case are known and these solids are supposed to be respectively in shape relation.

  18. Functional Properties of Tooth Pulp Neurons Responding to Thermal Stimulation

    OpenAIRE

    Ahn, D.K.; Doutova, E.A.; McNaughton, K.; Light, A.R.; Närhi, M.; Maixner, W.

    2012-01-01

    The response properties of tooth pulp neurons that respond to noxious thermal stimulation of the dental pulp have been not well-studied. The present study was designed to characterize the response properties of tooth pulp neurons to noxious thermal stimulation of the dental pulp. Experiments were conducted on 25 male ferrets, and heat stimulation was applied by a computer-controlled thermode. Only 15% of tooth pulp neurons (n = 39) responded to noxious thermal stimulation of the teeth. Tooth ...

  19. A panorama of tooth wear during the medieval period.

    Science.gov (United States)

    Esclassan, Rémi; Hadjouis, Djillali; Donat, Richard; Passarrius, Olivier; Maret, Delphine; Vaysse, Frédéric; Crubézy, Eric

    2015-01-01

    Tooth wear is a natural phenomenon and a universal occurrence that has existed from the origin of humankind and depends on the way of life, especially diet. Tooth wear was very serious in ancient populations up to the medieval period. The aim of this paper is to present a global view of tooth wear in medieval times in Europe through different parameters: scoring systems, quantity and direction of wear, gender, differences between maxilla and mandible, relations with diet, caries, tooth malpositions and age.

  20. Mandatory Arrest Law in domestic violence cases and its implementation in New York City

    Directory of Open Access Journals (Sweden)

    Milivojević Sanja K.

    2002-01-01

    Full Text Available This paper contains the analysis of the Mandatory Arrest Law in domestic violence cases in New York State. Introduction includes the subject and main goals of the paper. Second chapter starts with historical development of the police response in domestic violence cases in New York before and after the Mandatory Arrest Law is passed, than analysis of the Law, and ends with one of the programs which Safe Horizon, Victim Service organization, developed in New York City. Third chapter gives the analysis of pro et contra arguments for mandatory arrest provision and results of surveys and studies, which were conducted in United States. In fourth chapter we present the analysis of the research conducted in two police precincts in New York City this year. Paper also contains the list of main problems in implementation of this Law in New York City.

  1. Arrest scenarios in concentrated protein solutions - from hard sphere glasses to arrested spinodal decomposition

    Science.gov (United States)

    Stradner, Anna; Bucciarelli, Saskia; Casal, Lucia; Foffi, Giuseppe; Thurston, George; Farago, Bela; Schurtenberger, Peter

    2014-03-01

    The occurrence of an arrest transition in concentrated colloid suspensions and its dependence on the interaction potential is a hot topic in soft matter. Such arrest transitions can also occur in concentrated protein solutions, as they exist e.g. in biological cells or are increasingly used in pharmaceutical formulations. Here we demonstrate the applicability of concepts from colloid science to understand the dynamics of concentrated protein solutions. In this presentation we report a combination of 3D light scattering, small-angle X-ray scattering and neutron spin echo measurements to study the structural properties as well as the collective and self diffusion of proteins in highly concentrated solutions on the relevant length and time scales. We demonstrate that various arrest scenarios indeed exist for different globular proteins. The proteins chosen are different bovine lens crystallins. We report examples of hard and attractive glass transitions and arrested spinodal decomposition directly linked to the effective pair potentials determined in static scattering experiments for the different proteins. We discuss these different arrest scenarios in view of possible applications of dense protein solutions as well as in view of their possible relevance for living systems.

  2. The Importance of Tooth Decay Prevention in Children under Three

    Science.gov (United States)

    Milgrom, Peter; Huebner, Colleen; Chi, Donald

    2010-01-01

    Tooth decay and tooth loss was once the norm but public health interventions have led to major improvements for most people. Nevertheless, not all children have benefited. Dental disease in young children is unacceptably high. Tooth decay is preventable. Early childhood educators are often the first to notice the problem. Professional…

  3. Tooth-marked small theropod bone: an extremely rare trace

    DEFF Research Database (Denmark)

    Jacobsen, Aase Roland

    2001-01-01

    Tooth-marked dinosaur bones provide insight into feeding behaviours and biting strategies of theropod dinosaurs. The majority of theropod tooth marks reported to date have been found on herbivorous dinosaur bones, although some tyrannosaurid bones with tooth marks have also been reported. In 1988...

  4. 21 CFR 872.3690 - Tooth shade resin material.

    Science.gov (United States)

    2010-04-01

    ...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3690 Tooth shade resin material. (a) Identification. Tooth shade resin material is a device composed of materials such as bisphenol-A glycidyl... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Tooth shade resin material. 872.3690 Section...

  5. Frequency and Risk Indicators of Tooth Decay among Pregnant Women in France: A Cross-Sectional Analysis

    OpenAIRE

    2012-01-01

    INTRODUCTION: Little is known on the prevalence of tooth decay among pregnant women. Better knowledge of tooth decay risk indicators during pregnancy could help to develop follow-up protocols for women at risk, along with better prevention strategies. The aim of this study was to assess the frequency of tooth decay and the number of decayed teeth per woman in a large sample of pregnant women in France, and to study associated risk indicators. METHODS: A secondary cross-sectional analysis of d...

  6. A newer simultaneous space creation, eruption, and adjacent root control spring for the management of impacted tooth

    Directory of Open Access Journals (Sweden)

    Dipti Shastri

    2014-01-01

    Full Text Available Usually, treatment of impaction includes: Welcome preparation (to create space, surgical exposure and attachment to the impacted tooth and the orthodontic guidance for the eruption of the impacted tooth. Sometimes, due to deficiency of space, creation of space for impacted tooth requires first, and space regaining efforts may require the distal movement of posterior teeth and or mesial movement of anterior teeth in the arch, but it may create some problems. To overcome the unwanted problem in this clinical situation and to reduce overall treatment duration of the patient, we have developed the Simultaneous space creation, Eruption and Adjacent root control spring to control crown as well as root movement.

  7. An inductive signalling network regulates mammalian tooth morphogenesis with implications for tooth regeneration.

    Science.gov (United States)

    Li, Z; Yu, M; Tian, W

    2013-10-01

    Sequential and reciprocal epithelial-mesenchymal interactions, essential throughout such aspects of tooth morphogenesis as patterning, size and number of teeth, involves a well-ordered series of inductive and permissive signals that exert global control over cell proliferation, differentiation and organogenesis. In particular, growth factors, transcription factors and their corresponding receptors, as well as other soluble morphogens, make up a regulatory network at the molecular level that synergistically or antagonistically controls intra-/inter-cellular signal transduction during odontogenesis. This review summarizes recent advances in the study of crucial signalling pathways, for example of BMPs, Wnt, Notch, Shh and FGF, with emphasis on the potential integrated signalling network responsible for tooth formation. Our work probes into the complexity of these inductive signalling pathways to promote the understanding of tooth regeneration. Additionally, our study provides further insights into therapeutic strategies for various dental abnormalities in patterning and number, such as tooth agenesis and supernumerary teeth.

  8. Testing of long-flashover arresters designed for distribution lines

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira Filho, Orsino; Mello, Darcy Ramalho de; Oliveira, Gloria Suzana Gomes de [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)], Emails: orsino@cepel.br, darcy@cepel.br, gloria@cepel.br; Podporkin, Georgij; Wey, Acacio [Streamer Electric Company (Russian Federation)], E-mails: georgij.podporkin@streamer.ru, acacio.wey@bighost.com.br

    2007-07-01

    Outages of overhead power lines due to lightning strokes are one of the main causes of shortages of electric supplies and economic losses of power utilities. Pole-top metal oxide arresters can protect distribution lines against induced over-voltages, but they can be destroyed in case of direct lightning stroke. Long Flashover Arresters (LFAs) have been developed and used successfully for this purpose and have no possibility of being destroyed because the current flows externally along its surface. Since field experience with 10 kV LFAs has been very successful, it was decided to work on developing 13.8 kV LFAs, considering that it is the predominant voltage level of overhead distribution lines in Brazil and other countries. The performance of LFA for quenching and dielectric tests has been investigated through laboratory tests under conditions that typically represent electrical energy distribution systems. Details about these tests and their results are presented in this paper. Information about their design and applications are also shortly presented (author)

  9. Computed tomography to quantify tooth abrasion

    Science.gov (United States)

    Kofmehl, Lukas; Schulz, Georg; Deyhle, Hans; Filippi, Andreas; Hotz, Gerhard; Berndt-Dagassan, Dorothea; Kramis, Simon; Beckmann, Felix; Müller, Bert

    2010-09-01

    Cone-beam computed tomography, also termed digital volume tomography, has become a standard technique in dentistry, allowing for fast 3D jaw imaging including denture at moderate spatial resolution. More detailed X-ray images of restricted volumes for post-mortem studies in dental anthropology are obtained by means of micro computed tomography. The present study evaluates the impact of the pipe smoking wear on teeth morphology comparing the abraded tooth with its contra-lateral counterpart. A set of 60 teeth, loose or anchored in the jaw, from 12 dentitions have been analyzed. After the two contra-lateral teeth were scanned, one dataset has been mirrored before the two datasets were registered using affine and rigid registration algorithms. Rigid registration provides three translational and three rotational parameters to maximize the overlap of two rigid bodies. For the affine registration, three scaling factors are incorporated. Within the present investigation, affine and rigid registrations yield comparable values. The restriction to the six parameters of the rigid registration is not a limitation. The differences in size and shape between the tooth and its contra-lateral counterpart generally exhibit only a few percent in the non-abraded volume, validating that the contralateral tooth is a reasonable approximation to quantify, for example, the volume loss as the result of long-term clay pipe smoking. Therefore, this approach allows quantifying the impact of the pipe abrasion on the internal tooth morphology including root canal, dentin, and enamel volumes.

  10. Life of a Tooth: A Visual Timeline

    Medline Plus

    Full Text Available ... friv Home InfoBites Find an AGD Dentist Your Family's Oral Health About the AGD Dental care and ... Tooth games Home | InfoBites | Find a Dentist | Your Family's Oral Health | Newsroom | RSS About AGD | Contact AGD | ...

  11. Restoration of the endodontically treated posterior tooth

    Directory of Open Access Journals (Sweden)

    Andrea Polesel

    2014-06-01

    Results and conclusions: Direct adhesive restorations, indirect bonded restorations and traditional full crown are three therapeutic options for the single posterior endodontically treated teeth. The amount of remaining sound tooth structure is the most significant factor influencing the therapeutic approach. The clinician's operative skill is a determining aspect for long-term success of adhesive inlays.

  12. Early Onset Charcot-Marie-Tooth Disease

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2005-06-01

    Full Text Available The clinical signs and genetic analysis of early-onset Charcot-Marie-Tooth disease (CMT in a 2-year-old boy and members of his family are reported from the Academic Medical Center, Amsterdam, and Sophia Children’s Hospital, Rotterdam, the Netherlands.

  13. Bleaching of the discolored traumatized tooth

    DEFF Research Database (Denmark)

    Dahl, Jon E.; Kopperud, Siemen E.; Pallesen, Ulla

    2017-01-01

    This chapter focuses on the treatment of discolored traumatized teeth, most of them being non-vital and subsequently, endodontically treated. Tooth bleaching based upon hydrogen peroxide as the active agent, applied directly or produced in a chemical reaction from sodium perborate or carbamide pe...... retreatment....

  14. EPR dosimetry with tooth enamel: A review.

    Science.gov (United States)

    Fattibene, Paola; Callens, Freddy

    2010-11-01

    When tooth enamel is exposed to ionizing radiation, radicals are formed, which can be detected using electron paramagnetic resonance (EPR) techniques. EPR dosimetry using tooth enamel is based on the (presumed) correlation between the intensity or amplitude of some of the radiation-induced signals with the dose absorbed in the enamel. In the present paper a critical review is given of this widely applied dosimetric method. The first part of the paper is fairly fundamental and deals with the main properties of tooth enamel and some of its model systems (e.g., synthetic apatites). Considerable attention is also paid to the numerous radiation-induced and native EPR signals and the radicals responsible for them. The relevant methods for EPR detection, identification and spectrum analyzing are reviewed from a general point of view. Finally, the needs for solid-state modelling and studies of the linearity of the dose response are investigated. The second part is devoted to the practical implementation of EPR dosimetry using enamel. It concerns specific problems of preparation of samples, their irradiation and spectrum acquisition. It also describes how the dosimetric signal intensity and dose can be retrieved from the EPR spectra. Special attention is paid to the energy dependence of the EPR response and to sources of uncertainties. Results of and problems encountered in international intercomparisons and epidemiological studies are also dealt with. In the final section the future of EPR dosimetry with tooth enamel is analyzed.

  15. EPR dosimetry with tooth enamel: A review

    Energy Technology Data Exchange (ETDEWEB)

    Fattibene, Paola, E-mail: paola.fattibene@iss.i [Istituto Superiore di Sanita, Department of Technology and Health, Viale Regina Elena 299, I-00161 Rome (Italy); Callens, Freddy, E-mail: freddy.callens@ugent.b [Ghent University, Department of Solid State Sciences, Krijgslaan 281-S1, B-9000 Gent (Belgium)

    2010-11-15

    When tooth enamel is exposed to ionizing radiation, radicals are formed, which can be detected using electron paramagnetic resonance (EPR) techniques. EPR dosimetry using tooth enamel is based on the (presumed) correlation between the intensity or amplitude of some of the radiation-induced signals with the dose absorbed in the enamel. In the present paper a critical review is given of this widely applied dosimetric method. The first part of the paper is fairly fundamental and deals with the main properties of tooth enamel and some of its model systems (e.g., synthetic apatites). Considerable attention is also paid to the numerous radiation-induced and native EPR signals and the radicals responsible for them. The relevant methods for EPR detection, identification and spectrum analyzing are reviewed from a general point of view. Finally, the needs for solid-state modelling and studies of the linearity of the dose response are investigated. The second part is devoted to the practical implementation of EPR dosimetry using enamel. It concerns specific problems of preparation of samples, their irradiation and spectrum acquisition. It also describes how the dosimetric signal intensity and dose can be retrieved from the EPR spectra. Special attention is paid to the energy dependence of the EPR response and to sources of uncertainties. Results of and problems encountered in international intercomparisons and epidemiological studies are also dealt with. In the final section the future of EPR dosimetry with tooth enamel is analyzed.

  16. Storing tooth segments for optimal esthetics

    NARCIS (Netherlands)

    Tuzuner, T.; Turgut, S.; Özen, B.; Kılınç, H.; Bagis, B.

    2016-01-01

    Objective: A fractured whole crown segment can be reattached to its remnant; crowns from extracted teeth may be used as pontics in splinting techniques. We aimed to evaluate the effect of different storage solutions on tooth segment optical properties after different durations. Study design: Sixty c

  17. Arrest History and Intimate Partner Violence Perpetration in a Sample of Men and Women Arrested for Domestic Violence.

    Science.gov (United States)

    Shorey, Ryan C; Ninnemann, Andrew; Elmquist, Joanna; Labrecque, Lindsay; Zucosky, Heather; Febres, Jeniimarie; Brasfield, Hope; Temple, Jeff R; Stuart, Gregory L

    2012-01-01

    Intimate partner violence (IPV) is a serious and prevalent problem throughout the United States. Currently, individuals arrested for domestic violence are often court mandated to batterer intervention programs (BIPs). However, little is known about the arrest histories of these individuals, especially women. The current study examined the arrest histories of men (n = 303) and women (n = 82) arrested for domestic violence and court-referred to BIPs. Results demonstrated that over 30% of the entire sample had been previously arrested for a non-violent offense, and over 25% of the participants had been previously arrested for a violent offense other than domestic violence. Moreover, men were arrested significantly more frequently for violence-related and non-violent offenses than their female counterparts. In addition, men were more likely than women to have consumed binge-levels of alcohol prior to the offense that led to their most recent arrest and court-referral to a BIP. Lastly, arrest history was positively associated with physical and psychological aggression perpetration against an intimate partner for men only, such that more previous arrests were associated with more frequent aggression. These results provide evidence that many men and women arrested for domestic violence have engaged in a number of diverse criminal acts during their lifetimes, suggesting that BIPs may need to address general criminal behavior.

  18. Malnutrition has no effect on the timing of human tooth formation.

    Science.gov (United States)

    Elamin, Fadil; Liversidge, Helen M

    2013-01-01

    The effect of nutrition on the timing of human tooth formation is poorly understood. Delays and advancements in dental maturation have all been reported as well as no effect. We investigated the effect of severe malnutrition on the timing of human tooth formation in a large representative sample of North Sudanese children. The sample (1102 males, 1013 females) consisted of stratified randomly selected healthy individuals in Khartoum, Sudan, aged 2-22 years using a cross-sectional design following the STROBE statement. Nutritional status was defined using WHO criteria of height and weight. Body mass index Z-scores and height for age Z-scores of ≤-2 (cut-off) were used to identify the malnourished group (N = 474) while the normal was defined by Z-scores of ≥0 (N = 799). Clinical and radiographic examination of individuals, with known ages of birth was performed including height and weight measurements. Mandibular left permanent teeth were assessed using eight crown and seven root established tooth formation stages. Mean age at entry and mean age within tooth stages were calculated for each available tooth stage in each group and compared using a t-test. Results show the mean age at entry and mean age within tooth stages were not significantly different between groups affected by severe malnutrition and normal children (p>0.05). This remarkable finding was evident across the span of dental development. We demonstrate that there is little measurable effect of sustained malnutrition on the average timing of tooth formation. This noteworthy finding supports the notion that teeth have substantial biological stability and are insulated from extreme nutritional conditions compared to other maturing body systems.

  19. Malnutrition has no effect on the timing of human tooth formation.

    Directory of Open Access Journals (Sweden)

    Fadil Elamin

    Full Text Available The effect of nutrition on the timing of human tooth formation is poorly understood. Delays and advancements in dental maturation have all been reported as well as no effect. We investigated the effect of severe malnutrition on the timing of human tooth formation in a large representative sample of North Sudanese children. The sample (1102 males, 1013 females consisted of stratified randomly selected healthy individuals in Khartoum, Sudan, aged 2-22 years using a cross-sectional design following the STROBE statement. Nutritional status was defined using WHO criteria of height and weight. Body mass index Z-scores and height for age Z-scores of ≤-2 (cut-off were used to identify the malnourished group (N = 474 while the normal was defined by Z-scores of ≥0 (N = 799. Clinical and radiographic examination of individuals, with known ages of birth was performed including height and weight measurements. Mandibular left permanent teeth were assessed using eight crown and seven root established tooth formation stages. Mean age at entry and mean age within tooth stages were calculated for each available tooth stage in each group and compared using a t-test. Results show the mean age at entry and mean age within tooth stages were not significantly different between groups affected by severe malnutrition and normal children (p>0.05. This remarkable finding was evident across the span of dental development. We demonstrate that there is little measurable effect of sustained malnutrition on the average timing of tooth formation. This noteworthy finding supports the notion that teeth have substantial biological stability and are insulated from extreme nutritional conditions compared to other maturing body systems.

  20. COMPARISON OF THE TOOTH BRUSHING HABITS OF PRIMARY SCHOOL AGE CHILDREN AND THEIR PARENTS

    Directory of Open Access Journals (Sweden)

    Ceren Damla Özbek

    2015-01-01

    Full Text Available Purpose: As they grow, children develop their attitude and behavior related to tooth brushing by taking their parents’ oral-dental health behavior as an example. The purpose of this study was to assess whether there was a similarity in tooth brushing between primary school-age children and their parents presenting to the Department of Oral, Dental and Jaw Diseases and Surgery and the Department of Pedodontics, School of Dental Medicine, Istanbul University. Patients and Methods: The study included 126 children and their parents, as totally 252 subjects. The data on oral hygiene of the subjects were obtained using a questionnaire form including questions on the qualitative-quantitative tooth brushing habits of the children and their parents and the socio-demographic characteristics of their families. Results: In most of the cases, there was a similarity between children and their parents in terms of frequency of dentist visits, the therapy they underwent in their last dentist visit, the cause of caries, the frequency of tooth brushing, the material used for oral hygiene, the duration of tooth brushing, method of tooth brushing, and tooth sites most brushed, which showed a significant association between children and their parents (p<0.01. Conclusion: Correct knowledge given to the children by their families will positively affect the oral-dental health of the children. Thus, firstly, correct knowledge should be given to the parents so that they can successfully carry out their responsibility in being the correct model for their children in oral-dental health.

  1. Is tooth wear in the primary dentition predictive of tooth wear in the permanent dentition? Report from a longitudinal study.

    LENUS (Irish Health Repository)

    Harding, M A

    2010-03-01

    To determine the prevalence of tooth wear in the permanent dentition of a sample of 12-year-old school children and establish whether an association exists between tooth wear recorded now and tooth wear recorded in their primary dentition at age five.

  2. Arrests of women for driving under the influence.

    Science.gov (United States)

    Shore, E R; McCoy, M L; Toonen, L A; Kuntz, E J

    1988-01-01

    Police records of arrests of women in Wichita, Kansas for driving under the influence (DUI) of alcohol for a 5-year period (1980-1984) were studied. The proportion of arrests of women increased from 10.6 to 14.5% of total arrested. Women in their 20s comprised the largest age group; single women were greatly overrepresented. More than one-half of the arrested women were employed outside the home; a substantial proportion (30.8%) were unemployed at the time of arrest. The average blood alcohol level of those tested was 183 mg/dl. Characteristics of arrestees are discussed in terms of changes in the social roles and expectations of women. Although time of arrest was similar to that of men (i.e., night), arrests of women were more evenly spread across the days of the week. Within the 5-year period, the rate of recidivism for DUI was 7.43%. The implications of arrest and recidivism patterns are discussed. A change in legal and arrest procedures was found to have the same effect on arrests of women as it had on those of men, suggesting that the changes did not produce differential treatment by police.

  3. Preventing Tooth Decay: A Guide for Implementing Self-Applied Fluoride in Schools.

    Science.gov (United States)

    National Inst. of Dental Research (NIH), Bethesda, MD.

    This guidebook was developed to assist citizens in initiating programs to prevent tooth decay in young children through the use of fluoridation. It contains outlines for determining the needs of the school and community for fluoride in drinking water, and presents the various steps and activities that are necessary for developing and implementing…

  4. Reducing Early Childhood Tooth Decay: Strategies for State Medicaid and CHIP Dental Program Managers

    OpenAIRE

    2015-01-01

    Young children who are enrolled in Medicaid or the Children’s Health Insurance Program (CHIP) can be at risk for developing early childhood caries (ECC). ECC is a chronic bacterial infection that causes severe tooth decay and can begin to develop before baby teeth erupt.

  5. A TOOTH TATTOO WITH A PURPOSE: AN INNOVATIVE APPROACH

    Directory of Open Access Journals (Sweden)

    Neetu

    2014-01-01

    Full Text Available Skin is not the only place that can be decorated with a tattoo. You can decorate your tooth with amazing tattoos. Tooth tattoos and tooth jewels have become one of the hottest fashion trends , and a very popular arrival in cosmetic dentistry. But won’t it be a boon if it had some preventive or medicinal v alue. Yes tooth tattoos can act as indicators of once illness. These tiny electronic sensors can diagnose illnesses by 'tasting' your breath. This paper is an insight into how a tooth tattoos can pick up early warning signs of sickness or infection by bact eria in people's breath.

  6. Time series analysis as input for clinical predictive modeling: Modeling cardiac arrest in a pediatric ICU

    Directory of Open Access Journals (Sweden)

    Kennedy Curtis E

    2011-10-01

    Full Text Available Abstract Background Thousands of children experience cardiac arrest events every year in pediatric intensive care units. Most of these children die. Cardiac arrest prediction tools are used as part of medical emergency team evaluations to identify patients in standard hospital beds that are at high risk for cardiac arrest. There are no models to predict cardiac arrest in pediatric intensive care units though, where the risk of an arrest is 10 times higher than for standard hospital beds. Current tools are based on a multivariable approach that does not characterize deterioration, which often precedes cardiac arrests. Characterizing deterioration requires a time series approach. The purpose of this study is to propose a method that will allow for time series data to be used in clinical prediction models. Successful implementation of these methods has the potential to bring arrest prediction to the pediatric intensive care environment, possibly allowing for interventions that can save lives and prevent disabilities. Methods We reviewed prediction models from nonclinical domains that employ time series data, and identified the steps that are necessary for building predictive models using time series clinical data. We illustrate the method by applying it to the specific case of building a predictive model for cardiac arrest in a pediatric intensive care unit. Results Time course analysis studies from genomic analysis provided a modeling template that was compatible with the steps required to develop a model from clinical time series data. The steps include: 1 selecting candidate variables; 2 specifying measurement parameters; 3 defining data format; 4 defining time window duration and resolution; 5 calculating latent variables for candidate variables not directly measured; 6 calculating time series features as latent variables; 7 creating data subsets to measure model performance effects attributable to various classes of candidate variables; 8

  7. Computation Molecular Kinetics Model of HZE Induced Cell Cycle Arrest

    Science.gov (United States)

    Cucinotta, Francis A.; Ren, Lei

    2004-01-01

    Cell culture models play an important role in understanding the biological effectiveness of space radiation. High energy and charge (HZE) ions produce prolonged cell cycle arrests at the G1/S and G2/M transition points in the cell cycle. A detailed description of these phenomena is needed to integrate knowledge of the expression of DNA damage in surviving cells, including the determination of relative effectiveness factors between different types of radiation that produce differential types of DNA damage and arrest durations. We have developed a hierarchical kinetics model that tracks the distribution of cells in various cell phase compartments (early G1, late G1, S, G2, and M), however with transition rates that are controlled by rate-limiting steps in the kinetics of cyclin-cdk's interactions with their families of transcription factors and inhibitor molecules. The coupling of damaged DNA molecules to the downstream cyclin-cdk inhibitors is achieved through a description of the DNA-PK and ATM signaling pathways. For HZE irradiations we describe preliminary results, which introduce simulation of the stochastic nature of the number of direct particle traversals per cell in the modulation of cyclin-cdk and cell cycle population kinetics. Comparison of the model to data for fibroblast cells irradiated photons or HZE ions are described.

  8. Functional tooth restoration by allogeneic mesenchymal stem cell-based bio-root regeneration in swine.

    Science.gov (United States)

    Wei, Fulan; Song, Tieli; Ding, Gang; Xu, Junji; Liu, Yi; Liu, Dayong; Fan, Zhipeng; Zhang, Chunmei; Shi, Songtao; Wang, Songlin

    2013-06-15

    Our previous proof-of-concept study showed the feasibility of regenerating the dental stem cell-based bioengineered tooth root (bio-root) structure in a large animal model. Here, we used allogeneic dental mesenchymal stem cells to regenerate bio-root, and then installed a crown on the bio-root to restore tooth function. A root shape hydroxyapatite tricalcium phosphate scaffold containing dental pulp stem cells was covered by a Vc-induced periodontal ligament stem cell sheet and implanted into a newly generated jaw bone implant socket. Six months after implantation, a prefabricated porcelain crown was cemented to the implant and subjected to tooth function. Clinical, radiological, histological, ultrastructural, systemic immunological evaluations and mechanical properties were analyzed for dynamic changes in the bio-root structure. The regenerated bio-root exhibited characteristics of a normal tooth after 6 months of use, including dentinal tubule-like and functional periodontal ligament-like structures. No immunological response to the bio-roots was observed. We developed a standard stem cell procedure for bio-root regeneration to restore adult tooth function. This study is the first to successfully regenerate a functional bio-root structure for artificial crown restoration by using allogeneic dental stem cells and Vc-induced cell sheet, and assess the recipient immune response in a preclinical model.

  9. The sequential seeding of epithelial and mesenchymal cells for tissue-engineered tooth regeneration.

    Science.gov (United States)

    Honda, Masaki J; Tsuchiya, Shuhei; Sumita, Yoshinori; Sagara, Hiroshi; Ueda, Minoru

    2007-02-01

    Progress is being made toward regenerating teeth by seeding dissociated postnatal odontogenic cells onto scaffolds and implanting them in vivo, but tooth morphology remains difficult to control. In this study, we aimed to facilitate tooth regeneration using a novel technique to sequentially seed epithelial cells and mesenchymal cells so that they formed appropriate interactions in the scaffold. Dental epithelium and mesenchyme from porcine third molar teeth were enzymatically separated and dissociated into single cells. Mesenchymal cells were seeded onto the surface of the scaffold and epithelial cells were then plated on top so that the two cell types were in direct contact. The cell-scaffold constructs were evaluated in vitro and also implanted into immunocompromised rats for in vivo analysis. Control groups included constructs where direct contact between the two cell types was prevented. In scaffolds seed using the novel technique, alkaline phosphatase activity was significantly greater than controls, the tooth morphology in vivo was developed in similar to that of natural tooth, and only one tooth structure formed in each scaffold. These results suggest that the novel cell-seeding technique could be useful for regulating the morphology of regenerated teeth.

  10. Locked Mouths: Tooth Loss in a Women’s Prison in Northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Iris Sant’ Anna Araújo Rodrigues

    2014-01-01

    Full Text Available Background. Prisoners, in general, exhibit unsatisfactory oral conditions, especially with regard to the large number of missing teeth and with untreated caries. The aim of this study was to assess tooth loss, use of and need for prosthetic rehabilitation, and use of dental services among inmates. A cross-sectional study involving 65 inmates was developed at the Regional Women’s Prison of Campina Grande, Brazil. Data regarding sociodemographic and sentencing profile, use of dental services, dental morbidity, and self-perceived oral health impacts were investigated. Chi-square, Pearson, and Kruskal-Wallis (P<0.05 statistical tests were used. The mean tooth loss was 11.3 teeth. Significant association between tooth loss and oral health satisfaction (P=0.049, self-perceived need for dental prosthesis (P<0.001, uncomfortable teeth brushing (P=0.005, difficult speaking (P=0.002, and difficulty in performing routine tasks (P=0.025 was observed. It was observed that 29.2% of inmates were using some type of prosthesis, all deemed unsuitable for use, and 78.5% of inmates needed prosthetic rehabilitation. The oral health condition of the population studied was found to be poor, and prisoners showed significant tooth loss and need for dentures, with the aggravation of having tooth extraction as the major reason for seeking dental care.

  11. The Role of Mechanical Force in Molecular and Cellular during Orthodontic Tooth Movement

    Directory of Open Access Journals (Sweden)

    Ida Bagus Narmada

    2012-10-01

    Full Text Available Application of mechanical force on abnormally positioned tooth, cause changes in tooth location and transmitted to the bone ia the periodontal ligament (PDL produce orthodontic tooth movement. This force application is further way that remodeling in the area occurs. In order to develop biological strategies for enhancing this movement of teeth in bone, the underlying mechanisms of bone resorption and apposition should be understood in detail. Analysis of gingival crevicular fluid (GCF may be a good means of examining the on going molecular and cellular process associated with gingival and bone turnover during orthodontic tooth movement. If it could be possible to biologically monitor and predict the outcome of orthodontic force, then the appliance management could be based on dividual tissue response and the effectiveness of the treatment could be improved and understanding their biology is critical to finding ways to modify bone biology to move teeth faster. The present article reviewed a short introduction to some mayors advanced mechanical force in molecular and cellular biology during orthodontic tooth movement.DOI: 10.14693/jdi.v15i3.30

  12. Primary cilia regulate Shh activity in the control of molar tooth number.

    Science.gov (United States)

    Ohazama, Atsushi; Haycraft, Courtney J; Seppala, Maisa; Blackburn, James; Ghafoor, Sarah; Cobourne, Martyn; Martinelli, David C; Fan, Chen-Ming; Peterkova, Renata; Lesot, Herve; Yoder, Bradley K; Sharpe, Paul T

    2009-03-01

    Primary cilia mediate Hh signalling and mutations in their protein components affect Hh activity. We show that in mice mutant for a cilia intraflagellar transport (IFT) protein, IFT88/polaris, Shh activity is increased in the toothless diastema mesenchyme of the embryonic jaw primordia. This results in the formation of ectopic teeth in the diastema, mesial to the first molars. This phenotype is specific to loss of polaris activity in the mesenchyme since loss of Polaris in the epithelium has no detrimental affect on tooth development. To further confirm that upregulation of Shh activity is responsible for the ectopic tooth formation, we analysed mice mutant for Gas1, a Shh protein antagonist in diastema mesenchyme. Gas1 mutants also had ectopic diastema teeth and accompanying increased Shh activity. In this context, therefore, primary cilia exert a specific negative regulatory effect on Shh activity that functions to repress tooth formation and thus determine tooth number. Strikingly, the ectopic teeth adopt a size and shape characteristic of premolars, a tooth type that was lost in mice around 50-100 million years ago.

  13. Cutting blade dentitions in squaliform sharks form by modification of inherited alternate tooth ordering patterns

    Science.gov (United States)

    Underwood, Charlie; Johanson, Zerina; Smith, Moya Meredith

    2016-11-01

    The squaliform sharks represent one of the most speciose shark clades. Many adult squaliforms have blade-like teeth, either on both jaws or restricted to the lower jaw, forming a continuous, serrated blade along the jaw margin. These teeth are replaced as a single unit and successor teeth lack the alternate arrangement present in other elasmobranchs. Micro-CT scans of embryos of squaliforms and a related outgroup (Pristiophoridae) revealed that the squaliform dentition pattern represents a highly modified version of tooth replacement seen in other clades. Teeth of Squalus embryos are arranged in an alternate pattern, with successive tooth rows containing additional teeth added proximally. Asynchronous timing of tooth production along the jaw and tooth loss prior to birth cause teeth to align in oblique sets containing teeth from subsequent rows; these become parallel to the jaw margin during ontogeny, so that adult Squalus has functional tooth rows comprising obliquely stacked teeth of consecutive developmental rows. In more strongly heterodont squaliforms, initial embryonic lower teeth develop into the oblique functional sets seen in adult Squalus, with no requirement to form, and subsequently lose, teeth arranged in an initial alternate pattern.

  14. 'Split posterior tooth': conservative clinical re-attachment.

    Science.gov (United States)

    Abraham, Sathish; Chacko, Lisa Neelathil

    2014-07-30

    Trauma is the prime causative factor for fracture of teeth/dentition. Many procedural management options are followed successfully in relation to the anterior teeth. However, most posterior cases where the tooth is fractured have only limited options to pursue to save the tooth. Fractured teeth, whether they are vital/non-vital, are predominantly managed with surgical options. This paper discusses a conservative approach to reattaching a split posterior tooth. A split tooth situation is mostly an absolute indication for extraction, but the clinician may go in for extensive surgical procedures if he/she wishes to save it. The reattachment of the tooth can be successfully done and it can be put to function. This paper discusses how a split posterior tooth can be treated successfully, although depending on multiple factors. A full crown cemented after successful reattachment and root canal therapy would provide sufficient support in order for the tooth to heal.

  15. 齿梳式油茶果采摘机采摘执行机构的研制与试验%Development and test of picking actor in oil-tea camellia fruit picking machine of tooth comb type

    Institute of Scientific and Technical Information of China (English)

    高自成; 李立君; 李昕; 闵淑辉; 易春峰

    2013-01-01

      为了实现油茶果采摘的机械化,该文论述了齿梳式油茶果采摘机执行机构的研制和试验,重点论述了可避让式采摘头、多自由度采摘臂的设计。建立了空间坐标系,应用D-H矩阵变换,建立了采摘执行机构中采摘齿的空间运动方程。现场采摘试验表明,当齿梳式采摘头上升速度约为0.8 m/s左右,采摘头回转速度约为15 r/min时,既可以获得较高的采摘效率,又能使采摘范围内的漏摘率控制在3.2%以内,同时保证花蕾的掉落率控制在3%以内,从而验证了齿梳式油茶果采摘机的可行性。%Oil-tea camellia is one of the most important economic forest products in southern China, and it has a characteristic of whose florescence overlaps with the fruiting period. During the fruiting period, the fruits should be picked, while buds falling should be avoided. At present, the oil-tea camellia fruit picking is finished by the classical manual method that results in high cost and lower efficiency. With the promotion of the good varieties and the cultivation method of oil-tea camellia, mechanization and intellectualization of fruit picking have become an important aspect in upgrading the oil-tea industry as well as one of the important development directions of forestry machinery. This paper discussed the development and test of the picking machine of the toothcomb type from several aspects as the following. Firstly, the design of the rotary picking head and the picking arm of the machine were discussed. The picking arm, which consists of two parallel quadrilateral mechanisms connected in series, locates on the end of the picking arm. This kind of structure makes it easy to keep the posture of the picking head during the picking process. The rotary picking head consists of three parallel quadrilateral mechanisms connected in parallel, revolving around the common axis. This type of picking head can increase the picking efficiency

  16. Predictors for outcome among cardiac arrest patients

    DEFF Research Database (Denmark)

    Wibrandt-Johansen, Ida Maria; Norsted, Kristine; Schmidt, Henrik;

    2015-01-01

    BackgroundIn the past decade, early treatment of cardiac arrest (CA) victims has been improved in several ways, leading to more optimistic over all prognoses. However, the global survival rate after out-of-hospital CA (OHCA) is still not more than 5-10%. With a better knowledge of the predictors...... determined the 90-day mortality and neurological outcome at discharge for CA patients treated with therapeutic hypothermia (TH), in regard to determine the importance of the predictors for mortality and neurological outcome, with emphasize on combining initial rhythm and time to return of spontaneous...

  17. Hydroxyapatite coating on damaged tooth surfaces by immersion

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Byoung-Ki; Ryu, Su-Chak [Department of Nanomaterials Engineering, College of Nanoscience and Nanotechnology, Pusan National University, Miryang, 607-706 (Korea, Republic of); Sun, Fangfang; Koh, Kwangnak; Han, Dong-Wook; Lee, Jaebeom, E-mail: jaebeom@pusan.ac.k [Department of Nanomedical Engineering, College of Nanoscience and Nanotechnology, Pusan National University, Miryang, 607-706 (Korea, Republic of)

    2009-04-15

    Hydroxyapatite (HAp) was coated on scratched areas of a human tooth and HAp disks by the immersion method in a HAp colloidal solution (<=20{mu}m of average diameter dispersed in DI water). The surface morphologies of the scratched area after immersion for 1-3 months were investigated showing that the damaged surfaces were remarkably recovered. Then, the mechanical property and chemical stability of the HAp coating layers on both specimens were determined via the Vickers hardness test and concentration measurement of extracted Ca{sup 2+} ions, respectively, after strong acidic treatment. The cellular behavior of mouse calvaria-derived pre-osteoblastic cells (MC3T3-E1) was also examined on the HAp layers regenerated on micro-scratched HAp disks for the purpose of their potential applications on maxillofacial bone conservation and reconstruction for prosthetic dentistry, and artificial disk preparation of a vertebral column. The notable loss of Ca{sup 2+} ions under a highly acidic condition was not observed in the layers coated by HAp adsorption, indicating that the coating surface was well adhered with the original surfaces of the respective specimen. Moreover, the HAp adsorption did not adversely affect the adhesion, growth and proliferation of MC3T3-E1 cells on the coated HAp layers for up to 21 days. These results suggest that the HAp coating on the scratched areas of the tooth would be effectively applicable for the development of long-term prevention of micro-cleavage and tooth health supporters to reduce discoloration and further maxillofacial and orthopedic applications.

  18. A case of thyroid storm with cardiac arrest

    Directory of Open Access Journals (Sweden)

    Nakashima Y

    2014-05-01

    Full Text Available Yutaka Nakashima,1 Tsuneaki Kenzaka,2 Masanobu Okayama,3 Eiji Kajii31Department for Support of Rural Medicine, Yamaguchi Grand Medical Center, 2Division of General Medicine, Center for Community Medicine, Jichi Medical University School of Medicine, Shimotsuke, Japan; 3Division of Community and Family Medicine, Center for Community Medicine, Jichi Medical University School of Medicine, Shimotsuke, JapanAbstract: A 23-year-old man became unconscious while jogging. He immediately received basic life support from a bystander and was transported to our hospital. On arrival, his spontaneous circulation had returned from a state of ventricular fibrillation and pulseless electrical activity. Following admission, hyperthyroidism led to a suspicion of thyroid storm, which was then diagnosed as a possible cause of the cardiac arrest. Although hyperthyroidism-induced cardiac arrest including ventricular fibrillation is rare, it should be considered when diagnosing the cause of treatable cardiac arrest.Keywords: hyperthyroidism, ventricular fibrillation, treatable cardiac arrest, cardiac arrest, cardiopulmonary arrest

  19. Tooth reorientation affects tooth function during prey processing and tooth ontogeny in the lesser electric ray, Narcine brasiliensis.

    Science.gov (United States)

    Dean, Mason N; Ramsay, Jason B; Schaefer, Justin T

    2008-01-01

    The dental anatomy of elasmobranch fishes (sharks, rays and relatives) creates a functional system that is more dynamic than that of mammalian dentition. Continuous dental replacement (where new teeth are moved rostrally to replace older ones) and indirect fibrous attachment of the dentition to the jaw allow teeth to reorient relative to the jaw over both long- and short-term scales, respectively. In this study, we examine the processing behavior and dental anatomy of the lesser electric ray Narcine brasiliensis (Olfers, 1831) to illustrate that the freedom of movement of elasmobranch dentition allows a functional flexibility that can be important for complex prey processing behaviors. From static manipulations of dissected jaws and observations of feeding events in live animals, we show that the teeth rotate during jaw protrusion, resulting in a secondary grasping mechanism that likely serves to hold prey while the buccal cavity is flushed free of sediment. The function of teeth is not always readily apparent from morphology; in addition to short-term reorientation, the long-term dental reorientation during replacement allows a given tooth to serve multiple functions during tooth ontogeny. Unlike teeth inside the mouth, the cusps of external teeth (on the portion of the tooth pad that extends past the occlusal plane) lay flat, such that the labial faces act as a functional battering surface, protecting the jaws during prey excavation.

  20. High velocity air microabrasion for conservative tooth preparation: the principle and the clinical procedure.

    Science.gov (United States)

    Feinman, R A

    1995-10-01

    Various technologies within the dental armamentarium are applied to achieve the precise tooth preparations required for the different types of restorations. This article reintroduces the air microabrasion technique, which was first presented in 1945. The popular use of this technique had been postponed, pending the decrease in cost and development of compatible restorative materials to repair the tooth structure. With increased patient demand for less invasive preparation techniques and the decrease of the equipment cost, the use of air microbrasion for tooth preparation has been recognized. The history of the technology, its function, indications, advantages, and limitations are discussed, and a step-by-step clinical procedure is presented. The learning objective of this article is to familiarize the readers with this preparation procedure, enhancing the knowledge of preparation options.

  1. Tooth auto-transplantation as an alternative treatment option: A literature review

    Science.gov (United States)

    Nimčenko, Tatjana; Omerca, Gražvydas; Varinauskas, Vaidas; Bramanti, Ennio; Signorino, Fabrizio; Cicciù, Marco

    2013-01-01

    Rapidly evolving implantation and alveolar ridge reconstruction techniques created a new area in modern dentistry where tooth loss is no longer a problem. Endless variations of implant's length, diameter, surface, and design along with autogenous, alogenous, aloplastic, or xenogenous bone substitutes made it possible to recreate physiological occlusion, esthetic and masticatory function. However, none of nowadays technologies in implant dentistry have the potential to adapt to a growth and development changes of a child's jaw. Therefore, patient's young age is a restriction for implantation and a particular challenge for a dentist willing to restore missing tooth. Thus, tooth auto-transplantation can be a good choice for treatment. The objective of this review is to underline the biologic principles required for successful auto-transplantation of teeth. Limits, indications, technique, and prognosis will be analyzed. PMID:23878556

  2. New regenerative treatment for tooth and periodontal bone defect associated with posttraumatic alveolar bone crush fracture.

    Science.gov (United States)

    Kiyokawa, Kensuke; Kiyokawa, Munekatsu; Takagi, Mikako; Rikimaru, Hideaki; Fukaya, Takuji

    2009-05-01

    We developed a new regenerative treatment of tooth and periodontal defect and tooth dislocation associated with posttraumatic alveolar bone crush fracture in the region of the maxillary anterior teeth. Using this method, dislocated teeth are first extracted and crushed alveolar bone is debrided. The dislocated teeth are then reimplanted, and cancellous iliac bone (bone marrow) is grafted to the area surrounding the teeth to regenerate periodontal bone. Tooth reimplantation was completely successful in 2 cases, and periodontal bone regenerated to a sufficient height with the iliac bone graft. Compared with the general method of treatment with a prosthesis (bridge), when using this method to treat cases such as these, there is no sacrifice of healthy teeth adjacent to the defect, and sufficient esthetic and functional recovery is possible. It is thought that this method could be applied as a new treatment of alveolar bone fracture in the future.

  3. Biological approach for management of anterior tooth trauma: Triple case report

    Directory of Open Access Journals (Sweden)

    Goenka P

    2010-09-01

    Full Text Available Anterior crown fractures are a common form of injury that mainly affect children and adolescents. The position of maxillary incisors and their eruptive pattern carries a significant risk for trauma. In the pre-adhesive era, fractured teeth needed to be restored either with pin-retained inlays or cast restorations that sacrificed healthy tooth structure and were a challenge for clinicians to match with adjacent teeth. The development of adhesive dentistry has allowed dentists to use the patient′s own fragment to restore the fractured tooth. Three cases are presented here with complicated crown fracture of maxillary central incisors; the reattachment of the fractured tooth segment in this case has been performed using different combinations of techniques, viz. simple reattachment, circumferential bevel and internal dentinal groove.

  4. Biological approach for management of anterior tooth trauma: Triple case report

    Directory of Open Access Journals (Sweden)

    Puneet Goenka

    2011-01-01

    Full Text Available Anterior crown fractures are a common form of injury that mainly affect children and adolescents. The position of maxillary incisors and their eruptive pattern carries a significant risk for trauma. In the pre-adhesive era, fractured teeth needed to be restored either with pin-retained inlays or cast restorations that sacrificed healthy tooth structure, and were a challenge for clinicians to match with adjacent teeth. The development of adhesive dentistry has allowed dentists to use the patient′s own fragment to restore the fractured tooth. Three cases are presented here with complicated crown fracture of maxillary central incisors; the reattachment of the fractured tooth segment in these cases has been performed using different combinations of techniques, viz. simple reattachment, circumferential bevel and internal dentinal groove.

  5. Biological approach for management of anterior tooth trauma: triple case report.

    Science.gov (United States)

    Goenka, Puneet; Dutta, Samir; Marwah, Nikhil

    2011-01-01

    Anterior crown fractures are a common form of injury that mainly affect children and adolescents. The position of maxillary incisors and their eruptive pattern carries a significant risk for trauma. In the pre-adhesive era, fractured teeth needed to be restored either with pin-retained inlays or cast restorations that sacrificed healthy tooth structure, and were a challenge for clinicians to match with adjacent teeth. The development of adhesive dentistry has allowed dentists to use the patient's own fragment to restore the fractured tooth. Three cases are presented here with complicated crown fracture of maxillary central incisors; the reattachment of the fractured tooth segment in these cases has been performed using different combinations of techniques, viz. simple reattachment, circumferential bevel and internal dentinal groove.

  6. Electrothermal model for complete metal-oxide surge arresters

    Energy Technology Data Exchange (ETDEWEB)

    Costa, E. Guedes da; Naidu, S.R. [UFPB, Dept. of Electrical Engineering, Campina Grande, PB (Brazil); Lima, A. Guedes de [CEFET-PB, Dept. of Mechanical Engineering, Joao Pessoa, PB (Brazil)

    2001-01-01

    A computational, electrothermal model for a complete metal-oxide surge arrester based on the implicit form of the finite-differences method is presented. The model is used to calculate the cooling curve after the application of overvoltages and the temperature variations during standard test. The model has been checked against experiments carried out on a test section and a complete surge arrester and the behaviour of a hypothetical surge arrester during standard tests simulated. (Author)

  7. Postoperative cardiac arrest in children with congenital heart abnormalities

    OpenAIRE

    2013-01-01

    BACKGROUND The exact survival rates and markers of survival after postoperative cardiac arrest in children with congenital heart abnormalities are unknown. METHODS In this one-year study, we identified children younger than seven years of age with postoperative cardiac arrest in our pediatric cardiac intensive care unit database. Parameters from perioperative, pre-arrest, and resuscitation periods were analyzed for these patients. Comparisons were made between survivors and non-survivors afte...

  8. Broken or knocked out tooth

    Science.gov (United States)

    ... 2016 Updated by: Michael Kapner, DDS, general and aesthetic dentistry, Norwalk Medical Center, Norwalk, CT. Review provided ... for EHRs For Developers U.S. National Library of Medicine 8600 Rockville Pike, Bethesda, MD 20894 U.S. Department ...

  9. Tooth formation - delayed or absent

    Science.gov (United States)

    ... 2016 Updated by: Michael Kapner, DDS, general and aesthetic dentistry, Norwalk Medical Center, Norwalk, CT. Review provided ... for EHRs For Developers U.S. National Library of Medicine 8600 Rockville Pike, Bethesda, MD 20894 U.S. Department ...

  10. Tooth auto-transplantation as an alternative treatment option: A literature review

    Directory of Open Access Journals (Sweden)

    Tatjana Nimcenko

    2013-01-01

    However, none of nowadays technologies in implant dentistry have the potential to adapt to a growth and development changes of a child′s jaw. Therefore, patient′s young age is a restriction for implantation and a particular challenge for a dentist willing to restore missing tooth. Thus, tooth auto-transplantation can be a good choice for treatment. The objective of this review is to underline the biologic principles required for successful auto-transplantation of teeth. Limits, indications, technique, and prognosis will be analyzed.

  11. Fragment reattachment associated with pulpotomy in a posterior tooth with incomplete root formation.

    Science.gov (United States)

    Alcântara, Carlos Eduardo Pinto; Corrêa-Faria, Patrícia; Tavano, Karine Taís Aguiar; Botelho, Adriana Maria

    2011-12-01

    This article reports a case of preserving pulp vitality combined with aesthetics and functional reconstruction of an immature permanent molar extensively destroyed because of a carious lesion. After a pulpotomy using calcium hydroxide, the tooth crown was restored by bonding a dental fragment obtained from an extracted tooth from another individual. Aspects of diagnosis and treatment that directly affect the prognosis of the techniques are discussed. Radiographic and clinical follow-up for two years showed complete root development and a very satisfactory restoration with regard to aesthetics and function.

  12. Detection of chipped tooth in gears by the novel vibration residual technology

    Directory of Open Access Journals (Sweden)

    Len Gelman

    2011-01-01

    Full Text Available Novel vibration residual technology is applied for the first time for detecting a partly-missing (chipped tooth in a gearbox of the machine fault simulator (MFS. One stage gearbox consists of two bevel gears. The load on the gearbox was applied by a magnetic brake system. An advanced automatic technology for the time synchronous averaging of the raw gear vibrations has been employed; this technology does not require speed data. An advanced technique based on the likelihood ratio is developed for decision making. A partly missing tooth has been continuously detected throughout the whole test duration without false alarms and missed detections.

  13. Successful emergency splenectomy during cardiac arrest due to cytomegalovirus-induced atraumatic splenic rupture

    DEFF Research Database (Denmark)

    Glesner, Matilde Kanstrup; Madsen, Kristian Rørbæk; Nielsen, Jesper Meng Rahn;

    2015-01-01

    A 27-year-old woman was admitted to the emergency department with fever and a petechial rash on suspicion of meningitis. Shortly after arriving she developed cardiac arrest. Blood work up showed severe lactate acidosis, anaemia and thrombocytopenia. A focused assessment with sonography in trauma...

  14. Non-surgical management of tooth hypersensitivity.

    Science.gov (United States)

    Clark, Danielle; Levin, Liran

    2016-10-01

    Tooth sensitivity is a common complaint of patients in dental practices. Studies have demonstrated dentinal hypersensitivity to affect 10-30% of the population. There are various potential causes of tooth sensitivity and a variety of available treatment options. This narrative review will discuss the possible aetiology of this condition, as well as the treatment modalities available. A tailor-made treatment plan that starts with the most non-invasive treatment options and escalates only when those options have proven insufficient in alleviating symptoms should be provided for each patient. Only after all non- and less-invasive methods have failed to reduce the symptoms should more invasive treatment options, such as root-coverage, be considered.

  15. Tooth in Ethmoid Sinus: A Case Report

    Directory of Open Access Journals (Sweden)

    Tayebe Kazemei

    2009-09-01

    Full Text Available Ectopic eruption of teeth occurs in a variety of locations.Commonly seen in palate and maxillary sinus, they have alsobeen reported in nasal cavity, orbit, mandibular condyle,coronoid process, and facial skin.Here, we report a rare case of recurrent sinusitis caused byectopic tooth in right ethmoid sinus and successful endoscopicremoval of it. The symptoms of the patient disappeared aftersurgery. Such case has not been yet reported in the Englishliterature.Ectopic tooth is an uncommon cause of sinusitis. It shouldbe considered in patients presenting with recurrent sinusitis unresponsiveto medical treatment. Computed tomography of thesinuses is the modality of choice for diagnosis. Endoscopic sinussurgery is the best method for management of such cases.

  16. Interdisciplinary management of single-tooth implants.

    Science.gov (United States)

    Spear, F M; Mathews, D M; Kokich, V G

    1997-03-01

    Orthodontists treat many patients who are missing maxillary lateral incisors and/or mandibular second premolars. In the past, if the canines could not be substituted for lateral incisors, conventional full-coverage bridges were the common restoration. Recently, resin-bonded Maryland bridges became a popular substitute for conventional bridges to avoid crowns on the nonrestored abutments. However, resin-bonded bridges have a poor long-term prognosis for retention, lasting on average about 10 years. Since implants were introduced into dentistry by Swedish researchers in the mid-1980s, they have become a promising substitute for conventional or resin-bonded bridges. However, to successfully place and restore single-tooth implants in young orthodontic patients several questions must be answered. This article will discuss the many interdisciplinary issues that are involved in placing and restoring single-tooth implants in orthodontic patients.

  17. Esthetics and vertical tooth position: orthodontic possibilities.

    Science.gov (United States)

    Kokich, V G

    1997-12-01

    Throughout the 1990s, esthetic dentistry has become a prominent part of the treatment protocol of most dentists. Patients have become more conscious of the benefits of a beautiful smile and are willing to invest time and money to improve the appearance of their teeth. Many of these patients can be treated with routine restorative procedures (crowns, composites, laminates) to achieve the desired results. However, some patients have problems with tooth position that create significant discrepancies in gingival levels which can compromise the esthetic result of restorative dentistry. Prerestorative orthodontic therapy can often resolve these tooth position problems and enhance the esthetic restoration. This article describes the indication, methods, and results achieved when orthodontics preceded restorative dentistry in the treatment of various esthetic challenges.

  18. Tooth structure and fracture strength of cavities

    DEFF Research Database (Denmark)

    Mondelli, José; Sene, Fábio; Ramos, Renata Pereira

    2007-01-01

    This study evaluated, in vitro, the loss of tooth substance after cavity preparation for direct and indirect restorations and its relationship with fracture strength of the prepared teeth. Sixty sound human maxillary first premolars were assigned to 6 groups (n=10). MOD direct composite cavities......) or 1/2 (Groups III and VI) of the intercuspal distance. Teeth were weighed (digital balance accurate to 0.001 g) before and after preparation to record tooth substance mass lost during cavity preparation. The prepared teeth were submitted to occlusal loading to determine their fracture strength using...... mass loss (13.91%) than composite resin preparations with the same width (10.02%). 1/2-inlay cavities had 21.34% of mass loss versus 16.19% for the 1/2-composite resin cavities. Fracture strength means (in kgf) were: GI = 187.65; GII = 143.62; GIII = 74.10; GIV = 164.22; GV = 101.92; GVI = 50...

  19. Peptide-induced de novo bone formation after tooth extraction prevents alveolar bone loss in a murine tooth extraction model.

    Science.gov (United States)

    Arai, Yuki; Aoki, Kazuhiro; Shimizu, Yasuhiro; Tabata, Yasuhiko; Ono, Takashi; Murali, Ramachandran; Mise-Omata, Setsuko; Wakabayashi, Noriyuki

    2016-07-05

    Tooth extraction causes bone resorption of the alveolar bone volume. Although recombinant human bone morphogenetic protein 2 (rhBMP-2) markedly promotes de novo bone formation after tooth extraction, the application of high-dose rhBMP-2 may induce side effects, such as swelling, seroma, and an increased cancer risk. Therefore, reduction of the necessary dose of rhBMP-2 which can still obtain sufficient bone mass is necessary by developing a new osteogenic reagent. Recently, we showed that the systemic administration of OP3-4 peptide, which was originally designed as a bone resorption inhibitor, had osteogenic ability both in vitro and in vivo. This study evaluated the ability of the local application of OP3-4 peptide to promote bone formation in a murine tooth extraction model with a very low-dose of BMP. The mandibular incisor was extracted from 10-week-old C57BL6/J male mice and a gelatin hydrogel containing rhBMP-2 with or without OP3-4 peptide (BMP/OP3-4) was applied to the socket of the incisor. Bone formation inside the socket was examined radiologically and histologically at 21 days after the extraction. The BMP/OP3-4-group showed significant bone formation inside the mandibular extraction socket compared to the gelatin-hydrogel-carrier-control group or rhBMP-2-applied group. The BMP/OP3-4-applied mice showed a lower reduction of alveolar bone and fewer osteoclast numbers, suggesting that the newly formed bone inside the socket may prevent resorption of the cortical bone around the extraction socket. Our data revealed that OP3-4 peptide promotes BMP-mediated bone formation inside the extraction socket of mandibular bone, resulting in preservation from the loss of alveolar bone.

  20. Tooth morphogenesis and ameloblast differentiation are regulated by micro-RNAs.

    Science.gov (United States)

    Michon, Frederic; Tummers, Mark; Kyyrönen, Marika; Frilander, Mikko J; Thesleff, Irma

    2010-04-15

    Teeth form as appendages of the ectoderm and their morphogenesis is regulated by tissue interactions mediated by networks of conserved signal pathways. Micro-RNA (miRNA) pathway has emerged as important regulator of various aspects of embryonic development, but its function in odontogenesis has not been elucidated. We show that the expression of RNAi pathway effectors is dynamic during tooth morphogenesis and differentiation of dental cells. Based on microarray profiling we selected 8 miRNAs expressed during morphogenesis and 7 miRNAs in the incisor cervical loop containing the stem cell niche. These miRNAs were mainly expressed in the dental epithelium. Conditional deletion of Dicer-1 in the epithelium (Dcr(K14)(-)(/)(-)) resulted in rather mild but significant aberrations in tooth shape and enamel formation. The cusp patterns of the Dcr(K14)(-)(/)(-) molar crowns resembled the patterns of both ancestral muroid rodents and mouse mutants with modulated signal pathways. In the Dcr(K14)(-)(/)(-) incisors, longitudinal grooves formed on the labial surface and these were shown to result from ectopic budding of the progenitor epithelium in the cervical loop. In addition, ameloblast differentiation was impaired and resulted in deficient enamel formation in molars and incisors. To help the identification of candidate target genes of the selected tooth enriched miRNAs, we constructed a new ectodermal organ oriented database, miRTooth. The predicted targets of the selected miRNAs included several components of the main morphogenetic signal pathways regulating tooth development. Based on our findings we suggest that miRNAs modulate tooth morphogenesis largely by fine tuning conserved signaling networks and that miRNAs may have played important roles during tooth evolution.

  1. Frictional Effects on Gear Tooth Contact Analysis

    OpenAIRE

    Zheng Li; Ken Mao

    2013-01-01

    The present paper concentrates on the investigations regarding the situations of frictional shear stress of gear teeth and the relevant frictional effects on bending stresses and transmission error in gear meshing. Sliding friction is one of the major reasons causing gear failure and vibration; the adequate consideration of frictional effects is essential for understanding gear contact behavior accurately. An analysis of tooth frictional effect on gear performance in spur gear is presented us...

  2. Surviving Sudden Cardiac Arrest: A Pilot Qualitative Survey Study of Survivors.

    Science.gov (United States)

    Sawyer, Kelly N; Brown, Frances; Christensen, Roxanne; Damino, Colleen; Newman, Mary M; Kurz, Michael C

    2016-06-01

    Research describing survivors of sudden cardiac arrest (SCA) has centered on quantifying functional ability, perceived quality of life, and neurocognitive assessment. Many gaps remain, however, regarding survivors' psychosocial perceptions of life in the aftermath of cardiac arrest. An important influence upon those perceptions is the presence of support and its role in a survivor's life. An Internet-based pilot survey study was conducted to gather data from SCA survivors and friends and/or family members (FFMs) representing their support system. The survey was distributed to members of the Sudden Cardiac Arrest Foundation (SCAF) via the Internet by SCAF leadership. Questions included both discrete multiple-choice and open-ended formats. Inductive thematic analyses were completed by three independent researchers trained in qualitative research methodology to identify primary themes consistent among study participants until thematic saturation was achieved. No statistical inferences were made. A total of 205 surveys were returned over the 5-month study period (July to November 2013); nine were received blank, leaving 196 surveys available for review. Major themes identified for survivors (N = 157) include the significance of and desire to share experiences with others; subculture identification (unique experience from those suffering a heart attack); and the need to seek a new normal, both personally and inter-personally. Major themes identified for FFMs (N = 39) include recognition of loved one's memory loss; a lack of information at discharge, including expectations after discharge; and concern for the patient experiencing another cardiac arrest. This pilot, qualitative survey study suggests several common themes important to survivors, and FFMs, of cardiac arrest. These themes may serve as a basis for future patient-centered focus groups and the development of patient-centered guidelines for patients and support persons of those surviving cardiac arrest.

  3. Influence of musical instruments on tooth positions.

    Science.gov (United States)

    Herman, E

    1981-08-01

    A 2-year longitudinal investigation was conducted at five New York City junior high schools on 11- to 13-year-old children starting instrumental music education to determine what tooth movement, if any, resulted from the playing of certain musical instruments. Questionnaires, interviews, oral examinations, and dental casts were used at the start of instrumental study, after one year, and then after a second year. Statistically significant anterior tooth movements occurred in an overwhelming majority of the instrumentalists, while negligible movements were recorded for the controls over this period. As a result of this study, certain recommendations can be made by dentists when they are asked to suggest instruments which are dentally suited for children. In most cases they can suggest more than one instrument which would be of benefit dentally to the individual child, especially in the increase or reduction of overjet and overbite. The playing of the correct musical instrument can serve as an adjunct to the dentist or orthodontist in trying to accomplish certain tooth movements.

  4. Iatrogenic traumatic brain injury during tooth extraction.

    Science.gov (United States)

    Troxel, Mark

    2015-01-01

    An 8 yr old spayed female Yorkshire terrier was referred for evaluation of progressive neurological signs after a routine dental prophylaxis with tooth extractions. The patient was circling to the left and blind in the right eye with right hemiparesis. Neurolocalization was to the left forebrain. MRI revealed a linear tract extending from the caudal oropharynx, through the left retrobulbar space and frontal lobe, into the left parietal lobe. A small skull fracture was identified in the frontal bone through which the linear tract passed. Those findings were consistent with iatrogenic trauma from slippage of a dental elevator during extraction of tooth 210. The dog was treated empirically with clindamycin. The patient regained most of its normal neurological function within the first 4 mo after the initial injury. Although still not normal, the dog has a good quality of life. Traumatic brain injury is a rarely reported complication of extraction. Care must be taken while performing dental cleaning and tooth extraction, especially of the maxillary premolar and molar teeth to avoid iatrogenic damage to surrounding structures.

  5. Lightning arrester models enabling highly accurate lightning surge analysis; Koseidona kaminari surge kaiseki wo kano ni suru hiraiki model

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, T. [Chubu Electric Power Co. Inc., Nagoya (Japan); Funabashi, T.; Hagiwara, T.; Watanabe, H. [Meidensha Corp., Tokyo (Japan)

    1998-12-28

    Introduced herein are a dynamic behavior model for lightning arresters designed for power stations and substations and a flashover model for a lightning arresting device designed for transmission, both developed by the author et al. The author et al base their zinc oxide type lightning arrester model on the conventional static V-I characteristics, and supplement them with difference in voltage between static and dynamic characteristics. The model is easily simulated using EMTP (Electromagnetic Transients Program) etc. There is good agreement between the results of calculation performed using this model and actually measured values. Lightning arresting devices for transmission have come into practical use, and their effectiveness is introduced on various occasions. For the proper application of such devices, an analysis model capable of faithfully describing the flashover characteristics of arcing horns installed in great numbers along transmission lines, and of lightning arresting devices for transmission, are required. The author et al have newly developed a flashover model for the devices and uses the model for the analysis of lightning surges. It is found that the actually measured values of discharge characteristics of lightning arresting devices for transmission agree well with the values calculated by use of the model. (NEDO)

  6. Effective cauda equina decompression in two siblings with Charcot-Marie-Tooth disease type 1B

    NARCIS (Netherlands)

    van Doormaal, Tristan P C; van Ruissen, Fred; Miller, Kai J; Hoogendijk, Jessica E

    2016-01-01

    Two siblings with Charcot-Marie-Tooth (CMT) 1B due to a c.517G>C (p.Gly173Arg) mutation in the MPZ gene both developed an acute cauda syndrome with unbearable back pain radiating to both legs, progressive muscle weakness of the legs, and saddle hypesthesia with fecal and urinary incontinence. MRI sh

  7. Head Start Combats Baby Bottle Tooth Decay Among Native American Families.

    Science.gov (United States)

    Phillips, Margaret G.; Stubbs, Phyllis E.

    1987-01-01

    Presents current developments concerning nursing bottle caries--"baby bottle tooth decay"--and spotlights a program funded by Head Start to reduce the prevalence of these painful and disfiguring, but preventable, children's dental diseases among American Indians and Alaska Native families. (Author/BB)

  8. EQUIDISTANT TOOTH GENERATION ON NONCYLINDRICAL SURFACES FOR TWO-PARAMETER GEARING

    Directory of Open Access Journals (Sweden)

    Yuriy GUTSALENKO,

    2011-11-01

    Full Text Available The questions of design research of noncylindrical tooth surfaces for two-parameter gearing on example of bevel gears with constant normal pitch forgearing variators are been considered. Engineering is based on the special applied development of the mathematical theory of multiparametric mappings of space.

  9. Influence of tooth profile modification on spur gear dynamic tooth strain

    Science.gov (United States)

    Oswald, Fred B.; Townsend, Dennis P.

    1995-06-01

    This paper presents results of dynamic strain gage measurements performed on the NASA gear-noise rig. The experiments were part of a joint research program between NASA and the U.S. Army Research Laboratory to advance the technology of rotorcraft transmissions. Tests were performed on six sets of low contact ratio spur gears with different tooth profile modifications. Results presented include static and dynamic measurements of gear tooth strain taken over a matrix of operating conditions. The results demonstrate that a well-designed tooth profile modification can significantly reduce dynamic loads in spur gears, especially for gears which operate at high speed and under high torque. The two parabolic modifications tested were not as effective as linear modifications, possibly because the modification zone was too long.

  10. Ultrastructural organization and micromechanical properties of shark tooth enameloid.

    Science.gov (United States)

    Enax, Joachim; Janus, Anna M; Raabe, Dierk; Epple, Matthias; Fabritius, Helge-Otto

    2014-09-01

    The outer part of shark teeth is formed by the hard and mineral-rich enameloid that has excellent mechanical properties, which makes it a very interesting model system for the development of new bio-inspired dental materials. We characterized the microstructure, chemical composition and resulting local mechanical properties of the enameloid from teeth of Isurus oxyrinchus (shortfin mako shark) by performing an in-depth analysis using various high-resolution analytical techniques, including scanning electron microscopy, qualitative energy-dispersive X-ray spectroscopy and nanoindentation. Shark tooth enameloid reveals an intricate hierarchical arrangement of thin (50-80nm) and long (>1μm) crystallites of fluoroapatite with a high degree of structural anisotropy, which leads to exceptional mechanical properties. Both stiffness and hardness are surprisingly homogeneous in the shiny layer as well as in the enameloid: although both tooth phases differ in structure and composition, they show almost no orientation dependence with respect to the loading direction of the enameloid crystallites. The results were used to determine the structural hierarchy of shark teeth, which can be used as a base for establishing design criteria for synthetic bio-inspired and biomimetic dental composites.

  11. Cellular and Molecular Changes in Orthodontic Tooth Movement

    Directory of Open Access Journals (Sweden)

    Shahrul Hisham Zainal Ariffin

    2011-01-01

    Full Text Available Tooth movement induced by orthodontic treatment can cause sequential reactions involving the periodontal tissue and alveolar bone, resulting in the release of numerous substances from the dental tissues and surrounding structures. To better understand the biological processes involved in orthodontic treatment, improve treatment, and reduce adverse side effects, several of these substances have been proposed as biomarkers. Potential biological markers can be collected from different tissue samples, and suitable sampling is important to accurately reflect biological processes. This paper covers the tissue changes that are involved during orthodontic tooth movement such as at compression region (involving osteoblasts, tension region (involving osteoclasts, dental root, and pulp tissues. Besides, the involvement of stem cells and their development towards osteoblasts and osteoclasts during orthodontic treatment have also been explained. Several possible biomarkers representing these biological changes during specific phenomenon, that is, bone remodelling (formation and resorption, inflammation, and root resorption have also been proposed. The knowledge of these biomarkers could be used in accelerating orthodontic treatment.

  12. Therapeutic options in Charcot-Marie-Tooth diseases.

    Science.gov (United States)

    Mathis, Stéphane; Magy, Laurent; Vallat, Jean-Michel

    2015-04-01

    Charcot-Marie-Tooth (CMT) diseases represent a heterogeneous genetic disorder (more than 80 genes are implicated in these inherited neuropathies), but sharing a similar phenotype. In recent years, advances in molecular genetics and molecular biology, and also the development of various animal models of CMT, have led to a better understanding. Taken together, this knowledge represents a prerequisite for the development of future therapies in CMT, and in peripheral nervous system disorders in general. The efficacy of various substances has been shown in vitro and also in vivo (in animal models); but, no significant positive effect has yet been confirmed in humans. However, some of these trials are still in development, and we may expect positive results in the future. Although CMT is still an incurable disease, symptomatic treatments (physiotherapy, surgery, analgesic, etc.) are crucial to improve the quality of life of CMT patients.

  13. EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies), 2014 . Scientific Opinion on the substantiation of a health claim related to vitamin D and contribution to normal bone and tooth development pursuant to Article 14 of Regulation (EC) No 1924/2006

    DEFF Research Database (Denmark)

    Tetens, Inge

    Following an application from Specialised Nutrition Europe (formerly IDACE), submitted pursuant to Article 14 of Regulation (EC) No 1924/2006 via the Competent Authority of France, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver an opinion on the scientific...... for infants and young children. A claim on vitamin D and maintenance of normal bones and teeth in the general population has already been assessed with a favourable outcome. The Panel considers that the role of vitamin D in bone and tooth mineralisation and homeostasis applies to all ages, including infants...... and young children (from birth to three years). The Panel concludes that a cause and effect relationship has been established between the dietary intake of vitamin D and contribution to normal development of bones and teeth....

  14. Detecting inter-cusp and inter-tooth wear patterns in rhinocerotids.

    Directory of Open Access Journals (Sweden)

    Lucy A Taylor

    Full Text Available Extant rhinos are the largest extant herbivores exhibiting dietary specialisations for both browse and grass. However, the adaptive value of the wear-induced tooth morphology in rhinos has not been widely studied, and data on individual cusp and tooth positions have rarely been published. We evaluated upper cheek dentition of browsing Diceros bicornis and Rhinoceros sondaicus, mixed-feeding R. unicornis and grazing Ceratotherium simum using an extended mesowear method adapted for rhinos. We included single cusp scoring (EM(R-S to investigate inter-cusp and inter-tooth wear patterns. In accordance with previous reports, general mesowear patterns in D. bicornis and R. sondaicus were attrition-dominated and C. simum abrasion-dominated, reflecting their respective diets. Mesowear patterns for R. unicornis were more attrition-dominated than anticipated by the grass-dominated diet, which may indicate a low intake of environmental abrasives. EM(R-S increased differentiation power compared to classical mesowear, with significant inter-cusp and inter-tooth differences detected. In D. bicornis, the anterior cusp was consistently more abrasion-dominated than the posterior. Wear differences in cusp position may relate to morphological adaptations to dietary regimes. Heterogeneous occlusal surfaces may facilitate the comminution of heterogeneous browse, whereas uniform, broad grinding surfaces may enhance the comminution of physically more homogeneous grass. A negative tooth wear gradient was found in D. bicornis, R. sondaicus and R. unicornis, with wear patterns becoming less abrasion-dominated from premolars to molars. No such gradients were evident in C. simum which displayed a uniform wear pattern. In browsers, premolars may be exposed to higher relative grit loads, which may result in the development of wear gradients. The second premolar may also have a role in food cropping. In grazers, high absolute amounts of ingested abrasives may override other

  15. Bodybuilding supplementation and tooth decay.

    Science.gov (United States)

    Ali, M S; Batley, H; Ahmed, F

    2015-07-10

    Supplementation is a key component in bodybuilding and is increasingly being used by amateur weight lifters and enthusiasts to build their ideal bodies. Bodybuilding supplements are advertised to provide nutrients needed to help optimise muscle building but they can contain high amounts of sugar. Supplement users are consuming these products, while not being aware of their high sugar content, putting them at a higher risk of developing dental caries. It is important for dental professionals to recognise the increased risk for supplement users and to raise awareness, provide appropriate preventative advice and be knowledgeable of alternative products to help bodybuilders reach their goals, without increasing the risk of dental caries.

  16. Anaphylaxis with Latrodectus antivenin resulting in cardiac arrest.

    Science.gov (United States)

    Murphy, Christine M; Hong, Jeannie J; Beuhler, Michael C

    2011-12-01

    Latrodectus mactans antivenin is a safe and effective therapy for severe black widow spider envenomations when given to most patients. We report a case of a 37-year-old male with a history of asthma that was given L. mactans antivenin for symptoms related to a black widow envenomation and developed a severe anaphylactic reaction resulting in cardiac arrest. When traditional therapies failed, the patient was given methylene blue for anaphylactic shock resulting in a 30-h period of hemodynamic stability. Despite initial resuscitation, the patient ultimately died 40 h after presentation. Under the right circumstances, L. mactans antivenin remains a safe and effective therapy for severe black widow envenomations. However, anaphylaxis is a risk for those receiving this therapy, even when the antivenin is diluted and given as an infusion. We report the first death related to diluted L. mactans antivenin given as an infusion.

  17. Deep hypothermic circulatory arrest: real-life suspended animation.

    Science.gov (United States)

    Chau, Katherine H; Ziganshin, Bulat A; Elefteriades, John A

    2013-01-01

    Deep hypothermic circulatory arrest (DHCA) is a cerebral protection technique that was developed in the 1950s and popularized in the 1970s. It has become one of the three most common cerebral protection techniques currently used in aortic arch surgeries, with the other two being antegrade cerebral perfusion (ACP) and retrograde cerebral perfusion (RCP). At our institution, DHCA has been the cerebral protection technique of choice for over a quarter century. Our clinical experience with DHCA has been very positive, and our clinical studies have shown DHCA to have outcomes equal to (and sometimes better than) those of ACP and RCP, and DHCA to be very effective at preserving neurocognitive function. Other institutions, however, prefer ACP or RCP to DHCA. Each technique has its own set of pros and cons, and the question regarding which technique is the superior method for cerebral protection is hotly debated.

  18. Endogenous and Exogenous Substances Influencing the Orthodontic Tooth Movement

    Directory of Open Access Journals (Sweden)

    Mine Geçgelen Cesur

    2016-08-01

    Full Text Available Orthodontic tooth movement occurs as a result of prolonged application of controlled mechanical forces. Recent studies have focused on the effects of systemic or local applications of medications and the intake of dietary supplements as well as the mechanical forces. Factors affecting the orthodontic tooth movement are parathyroid hormone, thyroid hormones, estrogen, vitamin D3, eicosanoids, nonsteroidal anti-inflammatory drugs (NSAIDs, paracetamol, corticosteroids, bisphosphonates, cholesterol drugs, anticonvulsants, oral contraceptives, alcohol and nicotine use, nitric oxide, and fluoride. These medications have an important effect on the rate of tooth movement and treatment time. NSAIDs decrease tooth movement, but paracetamol has no effect. Parathyroid and thyroxin hormones increase tooth movement. Bisphosphonates have a strong inhibitory effect. Vitamin D3 stimulates tooth movement and dietary calcium seems to reduce it. It is important to discuss with patients about the consumption of these substances during orthodontic treatment.

  19. IBA analysis of a possible therapeutic ancient tooth inlay

    Science.gov (United States)

    Andrade, E.; Pineda, J. C.; Zavala, E. P.; Murillo, G.; Chavez, R.; Lazcurain, R.; Espinosa, Ma. L.; Villanueva, O.

    1998-03-01

    Five pre-Columbian human teeth from the same skeleton found during excavation in an ancient ceremonial center in Mexico, have been analyzed by two conventional Ion Beam Analysis (IBA) techniques: PIXE and 4He RBS. The anthropologists have estimated that the skeleton is about 2000 years old. X-ray radiography studies of one of these teeth have revealed that they contain an inlay in the tooth crown. The IBA methods have been used to study the inlay materials and also the tooth enamel. The IBA studies show that the tooth inlay materials have almost the same atomic composition as the tooth enamel. These results suggest that the tooth inlay were made for therapeutic purposes, using healthy tooth grains as inlay materials which were glued into the prepared teeth to fill it up.

  20. Resuscitation, prolonged cardiac arrest, and an automated chest compression device

    DEFF Research Database (Denmark)

    Risom, Martin; Jørgensen, Henrik; Rasmussen, Lars S;

    2010-01-01

    The European Resuscitation Council's 2005 guidelines for cardiopulmonary resuscitation (CPR) emphasize the delivery of uninterrupted chest compressions of adequate depth during cardiac arrest.......The European Resuscitation Council's 2005 guidelines for cardiopulmonary resuscitation (CPR) emphasize the delivery of uninterrupted chest compressions of adequate depth during cardiac arrest....

  1. Evolution of the dragonfly head-arresting system

    Science.gov (United States)

    Gorb, S. N.

    1999-01-01

    The arrester or fixation system of the head in adult Odonata is unique among arthropods. This system involves the organs of two body segments: the head and the neck. It consists of a skeleton–muscle apparatus that sets the arrester parts in motion. The parts comprise formations covered with complicated microstructures: fields of microtrichia on the rear surface of the head and post-cervical sclerites of the neck. The arrester immobilizes the head during feeding or when the dragonfly is in tandem flight. Thus, it may serve as an adaptation to save the head from violent mechanical disturbance and to stabilize gaze in a variety of behavioural situations. This study shows the evolutionary trend of the arrester in the order Odonata by using scanning electron microscopy and measurements of arrester structures in 227 species from 26 odonate families. The arrester design occurring in the Epiophlebiidae, Gomphidae, Neopetaliidae, Petaluridae and Chlorogomphinae is suggested to be the basic one. Two convergent pathways of head-arrester evolution among Zygoptera and Anisoptera are proposed. The possible functional significance of the arrester system is discussed.

  2. Predictive Value of Brain Arrest Neurological Outcome Scale (BrANOS) on Mortality and Morbidity After Cardiac Arrest

    Science.gov (United States)

    Şahutoğlu, Cengiz; Uyar, Mehmet; Demirağ, Kubilay; İsayev, Hasan; Moral, Ali Reşat

    2016-01-01

    Objective There are several prediction scales and parameters for prognosis after a cardiac arrest. One of these scales is the brain arrest neurological outcome scale (BrANOS), which consists of duration of cardiac arrest, Glasgow Coma Scale score and Hounsfield unit measured on cranial computed tomography (CT) scan. The objective of this study is to investigate the effectiveness of BrANOS on predicting the mortality and disability after a cardiac arrest. Methods We retrospectively investigated cardiac arrest patients who were hospitalized in our intensive care unit (ICU) within a 3-year period. Inclusion criteria were age over 18 years old, survival of more than 24 hours after cardiac arrest and availability of cranial CT. We recorded the age, sex, diagnosis, duration of cardiac arrest and hospital stay, mortality, Glasgow Outcome Score (GOS) and BrANOS score. The primary endpoint of the study was to establish the relationship between mortality and BrANOS score in patients who survived for more than 24 hours after a cardiac arrest. The secondary endpoint of the study was to determine the 2-year life expectancy and GOS after cardiac arrest. Results The mean age of the patients was 57±17 years (33 females, 67 males). ICU mortality rate was 57%. The BrANOS mean score was 10.3±3.2. There was a significant difference between survivors and non-survivors in terms of the BrANOS score (8.8±3.2 vs. 11.6±2.7; p14 predicted death with 100% accuracy. All the patients without disability had a BrANOS score of <10. The BrANOS score also correlated well with GOS (p<0.001). The 2-year life expectancy rate was 31% in patients who survived more than 24 hours after a cardiac arrest. Conclusion In this study, we demonstrated that BrANOS provided reliable data for prognostic evaluation after a cardiac arrest. PMID:28058140

  3. Sonosurgery for atraumatic tooth extraction: a clinical report.

    Science.gov (United States)

    Papadimitriou, Dimitrios E V; Geminiani, Alessandro; Zahavi, Thomas; Ercoli, Carlo

    2012-12-01

    The preservation of an intact labial plate during tooth extraction is a critical determinant of whether an immediate implant can be placed and is also an important predictor of the esthetic result. The purpose of this clinical report was to present a method for atraumatic tooth extraction by using an air-driven sonic instrument with specially designed inserts. This surgical technique provides the clinician with an efficient method for atraumatic tooth extraction and preservation of an intact labial plate.

  4. Modular Permanent Magnet Machines with Alternate Teeth Having Tooth Tips

    OpenAIRE

    Li, G. J.; Zhu, Z.Q.; Foster, M. P.; Stone, D. A.; Zhan, H.L.

    2015-01-01

    This paper presents single layer modular permanent magnet machines with either wound or unwound teeth with tooth tips. The structures with wound teeth having tooth tips are suitable for modular machines with slot number higher than pole number to compensate for the drop in winding factor due to the flux gaps in alternate stator teeth, accordingly to maintain or even to increase their average torques. However, the structures with unwound teeth having tooth tips are suitable for modular machine...

  5. A theropod tooth from the Late Triassic of southern Africa

    Indian Academy of Sciences (India)

    Sanghamitra Ray; Anusuya Chinsamy

    2002-06-01

    An isolated, large recurved and finely serrated tooth found associated with the prosauropod Euskelosaurus from the Late Triassic part of the Elliot Formation is described here. It is compared to the Triassic thecodonts and carnivorous dinosaurs and its possible affinity is discussed. The tooth possibly belongs to a basal theropod and shows some features similar to the allosauroids. This tooth is of significance, as dinosaur remains except for some footprints and trackways, are poorly known in the Late Triassic horizons of southern Africa.

  6. Association of national initiatives to improve cardiac arrest management with rates of bystander intervention and patient survival after out-of-hospital cardiac arrest

    DEFF Research Database (Denmark)

    Wissenberg, Mads; Lippert, Freddy K.; Folke, Fredrik

    2013-01-01

    resuscitation was attempted were identified between 2001 and 2010 in the nationwide Danish Cardiac Arrest Registry. Of 29 111 patients with cardiac arrest, we excluded those with presumed noncardiac cause of arrest (n = 7390) and those with cardiac arrests witnessed by emergency medical services personnel (n...

  7. Design of face-hobbed spiral bevel gears with reduced maximum tooth contact pressure and transmission errors

    Institute of Scientific and Technical Information of China (English)

    Vilmos Simon

    2013-01-01

    The aim of this study is to define optimal tooth modifications,introduced by appropriately chosen head-cutter geometry and machine tool setting,to simultaneously minimize tooth contact pressure and angular displacement error of the driven gear (transmission error) of face-hobbed spiral bevel gears.As a result of these modifications,the gear pair becomes mismatched,and a point contact replaces the theoretical line contact.In the applied loaded tooth contact analysis it is assumed that the point contact under load is spreading over a surface along the whole or part of the “potential” contact line.A computer program was developed to implement the formulation provided above.By using this program the influence of tooth modifications introduced by the variation in machine tool settings and in head cutter data on load and pressure distributions,transmission errors,and fillet stresses is investigated and discussed.The correlation between the ease-off obtained by pinion tooth modifications and the corresponding tooth contact pressure distribution is investigated and the obtained results are presented.

  8. Monitoring tooth profile faults in epicyclic gearboxes using synchronously averaged motor currents: Mathematical modeling and experimental validation

    Science.gov (United States)

    Ottewill, J. R.; Ruszczyk, A.; Broda, D.

    2017-02-01

    Time-varying transmission paths and inaccessibility can increase the difficulty in both acquiring and processing vibration signals for the purpose of monitoring epicyclic gearboxes. Recent work has shown that the synchronous signal averaging approach may be applied to measured motor currents in order to diagnose tooth faults in parallel shaft gearboxes. In this paper we further develop the approach, so that it may also be applied to monitor tooth faults in epicyclic gearboxes. A low-degree-of-freedom model of an epicyclic gearbox which incorporates the possibility of simulating tooth faults, as well as any subsequent tooth contact loss due to these faults, is introduced. By combining this model with a simple space-phasor model of an induction motor it is possible to show that, in theory, tooth faults in epicyclic gearboxes may be identified from motor currents. Applying the synchronous averaging approach to experimentally recorded motor currents and angular displacements recorded from a shaft mounted encoder, validate this finding. Comparison between experiments and theory highlight the influence of operating conditions, backlash and shaft couplings on the transient response excited in the currents by the tooth fault. The results obtained suggest that the method may be a viable alternative or complement to more traditional methods for monitoring gearboxes. However, general observations also indicate that further investigations into the sensitivity and robustness of the method would be beneficial.

  9. Fibrin glue mixed with platelet-rich fibrin as a scaffold seeded with dental bud cells for tooth regeneration.

    Science.gov (United States)

    Yang, Kai-Chiang; Wang, Chun-Hao; Chang, Hao-Hueng; Chan, Wing P; Chi, Chau-Hwa; Kuo, Tzong-Fu

    2012-11-01

    Odontogenesis is a complex process with a series of epithelial-mesenchymal interactions and odontogenic molecular cascades. In tissue engineering of teeth from stem cells, platelet-rich fibrin (PRF), which is rich in growth factors and cytokines, may improve regeneration. Accordingly, PRF was added into fibrin glue to enrich the microenvironment with growth factors. Unerupted second molar tooth buds were harvested from miniature swine and cultured in vitro for 3 weeks to obtain dental bud cells (DBCs). Whole blood was collected for the preparation of PRF and fibrin glue before surgery. DBCs were suspended in fibrin glue and then enclosed with PRF, and the DBC-fibrin glue-PRF composite was autografted back into the original alveolar sockets. Radiographic and histological examinations were used to identify the regenerated tooth structure 36 weeks after implantation. Immunohistochemical staining was used to detect proteins specific to tooth regeneration. One pig developed a complete tooth with crown, root, pulp, enamel, dentin, odontoblast, cementum, blood vessels, and periodontal ligaments in indiscriminate shape. Another animal had an unerupted tooth that expressed cytokeratin 14, dentin matrix protein-1, vascular endothelial growth factor, and osteopontin. This study demonstrated, using autogenic cell transplantation in a porcine model, that DBCs seeded into fibrin glue-PRF could regenerate a complete tooth.

  10. Sublingual Microcirculation is Impaired in Post-cardiac Arrest Patients

    DEFF Research Database (Denmark)

    G. Omar, Yasser; Massey, Michael; Wiuff Andersen, Lars;

    2013-01-01

    AIM: We hypothesized that microcirculatory dysfunction, similar to that seen in sepsis, occurs in post-cardiac arrest patients and that better microcirculatory flow will be associated with improved outcome. We also assessed the association between microcirculatory dysfunction and inflammatory...... markers in the post-cardiac arrest state. METHODS: We prospectively evaluated the sublingual microcirculation in post-cardiac arrest patients, severe sepsis/septic shock patients, and healthy control patients using Sidestream Darkfield microscopy. Microcirculatory flow was assessed using...... the microcirculation flow index (MFI) at 6 and 24h in the cardiac arrest patients, and within 6h of emergency department admission in the sepsis and control patients. RESULTS: We evaluated 30 post-cardiac arrest patients, 16 severe sepsis/septic shock patients, and 9 healthy control patients. Sublingual...

  11. Out-of-Hospital Cardiac Arrest in Denmark

    DEFF Research Database (Denmark)

    Wissenberg Jørgensen, Mads

    challenges, due to the victim’s physical location, which brings an inherent risk of delay (or altogether absence) of recognition and treatment of cardiac arrest. A low frequency of bystander cardiopulmonary resuscitation and low 30-day survival after out-of-hospital cardiac arrest were identified nearly ten......BACK COVER TEXT Cardiac arrest is an emergency medical condition characterized by the cessation of cardiac mechanical activity; without immediate and decisive treatment, a victim’s chances of survival are minimal. Out-of-hospital cardiac arrest is a particular arrest subgroup that poses additional...... years ago in Denmark. These findings led to several national initiatives to strengthen bystander resuscitation attempts and advance care. Despite these nationwide efforts, it was unknown prior to this project whether these efforts resulted in changes in resuscitation attempts by bystanders and changes...

  12. The regulation of tooth morphogenesis is associated with epithelial cell proliferation and the expression of Sonic hedgehog through epithelial-mesenchymal interactions

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, Kentaro; Murofushi, Mayumi [Faculty of Industrial Science and Technology, Tokyo University of Science, Chiba 278-8510 (Japan); Nakao, Kazuhisa; Morita, Ritsuko [Research Institute for Science and Technology, Tokyo University of Science, Chiba 278-8510 (Japan); Ogawa, Miho [Research Institute for Science and Technology, Tokyo University of Science, Chiba 278-8510 (Japan); Organ Technologies Inc., Tokyo 101-0048 (Japan); Tsuji, Takashi, E-mail: t-tsuji@rs.noda.tus.ac.jp [Faculty of Industrial Science and Technology, Tokyo University of Science, Chiba 278-8510 (Japan); Research Institute for Science and Technology, Tokyo University of Science, Chiba 278-8510 (Japan); Organ Technologies Inc., Tokyo 101-0048 (Japan)

    2011-02-18

    Research highlights: {yields} Bioengineered teeth regulated the contact area of epithelium and mesenchyme. {yields} The crown width is regulated by the contact area of the epithelium and mesenchyme. {yields} This regulation is associated with cell proliferation and Sonic hedgehog expression. {yields} The cusp number is correlated with the crown width of the bioengineered tooth. {yields} Cell proliferation and Shh expression areas regulate the tooth morphogenesis. -- Abstract: Ectodermal organs, such as the tooth, salivary gland, hair, and mammary gland, develop through reciprocal epithelial-mesenchymal interactions. Tooth morphologies are defined by the crown width and tooth length (macro-morphologies), and by the number and locations of the cusp and roots (micro-morphologies). In our current study, we report that the crown width of a bioengineered molar tooth, which was reconstructed using dissociated epithelial and mesenchymal cells via an organ germ method, can be regulated by the contact area between epithelial and mesenchymal cell layers. We further show that this is associated with cell proliferation and Sonic hedgehog (Shh) expression in the inner enamel epithelium after the germ stage has formed a secondary enamel knot. We also demonstrate that the cusp number is significantly correlated with the crown width of the bioengineered tooth. These findings suggest that the tooth micro-morphology, i.e. the cusp formation, is regulated after the tooth width, or macro-morphology, is determined. These findings also suggest that the spatiotemporal patterning of cell proliferation and the Shh expression areas in the epithelium regulate the crown width and cusp formation of the developing tooth.

  13. Evaluation of scaffold materials for tooth tissue engineering.

    Science.gov (United States)

    Ohara, Takayuki; Itaya, Toshimitsu; Usami, Kazutada; Ando, Yusuke; Sakurai, Hiroya; Honda, Masaki J; Ueda, Minoru; Kagami, Hideaki

    2010-09-01

    Recently, the possibility of tooth tissue engineering has been reported. Although there are a number of available materials, information about scaffolds for tooth tissue engineering is still limited. To improve the manageability of tooth tissue engineering, the effect of scaffolds on in vivo tooth regeneration was evaluated. Collagen and fibrin were selected for this study based on the biocompatibility to dental papilla-derived cells and the results were compared with those of polyglycolic acid (PGA) fiber and beta-tricalcium phosphate (beta-TCP) porous block, which are commonly used for tooth, dentin and bone tissue engineering. Isolated porcine tooth germ-derived cells were seeded onto one of those scaffolds and transplanted to the back of nude mice. Tooth bud-like structures were observed more frequently in collagen and fibrin gels than on PGA or beta-TCP, while the amount of hard tissue formation was less. The results showed that collagen and fibrin gel support the initial regeneration process of tooth buds possibly due to their ability to support the growth of epithelial and mesenchymal cells. On the other hand, maturation of tooth buds was difficult in fibrin and collagen gels, which may require other factors.

  14. Comparison between normal and special chain-drive toothing

    Energy Technology Data Exchange (ETDEWEB)

    Dolipski, M.

    1985-12-01

    A comparison of these two types of tooth arrangements on chain drives with round-link chains comes out clearly in favour of the special toothing. The article describes the advantages of this type of toothing. A proposal is made to use the special tooth arrangement in the construction of drive pocket wheels. Such a move would prevent the disastrous effects of links becoming jammed in the pockets during running-in and would consequently improve the service life of both chain and drive sprocket.

  15. Patient Discomfort Following Single-Tooth Implant Placement

    DEFF Research Database (Denmark)

    Spin-Neto, Rubens; Pontes, Ana Emília Farias; Wenzel, Ann

    2014-01-01

    Aims: Evaluate postoperative discomfort (pain, bleeding and swelling) in single-tooth implant patients submitted to immediate or conventional tooth restoration together with assessment of treatment time. Methods: Twenty-four patients who received single-tooth maxillary dental implants were randomly...... assigned to an IR (Immediate Restoration) or CR (Conventional Restoration) group. In IR, an implant was inserted and a provisional tooth crown was delivered within the same session, while in CR it was delivered three months after implantation. Pain (first three days), bleeding (first day) and swelling...

  16. Tooth modification and dynamic performance of the cycloidal drive

    Science.gov (United States)

    Ren, Zhong-Yi; Mao, Shi-Min; Guo, Wen-Chao; Guo, Zheng

    2017-02-01

    A new method of cycloid disc tooth modification is presented in this paper. Its main idea is to design the modification clearance curves to adapt to different modification targets. A detailed procedure of the new modification clearance curve, which can be defined by adjusting the position of 5 key points is developed. Numerical experiments are carried out to verify the effectiveness of the new method. A Multi-DOF nonlinear dynamic model of cycloidal speed reducer is established, then the cycloid disc rotational displacement and rotational velocity versus time of different modification clearance are solved by the Runge-kutta numerical method. The results show that this method can improve the carrying capability of cycloidal drive, eliminate noise and vibration and develop the transmission accuracy.

  17. Biological synthesis of tooth enamel instructed by an artificial matrix.

    Science.gov (United States)

    Huang, Zhan; Newcomb, Christina J; Bringas, Pablo; Stupp, Samuel I; Snead, Malcolm L

    2010-12-01

    The regenerative capability of enamel, the hardest tissue in the vertebrate body, is fundamentally limited due to cell apoptosis following maturation of the tissue. Synthetic strategies to promote enamel formation have the potential to repair damage, increase the longevity of teeth and improve the understanding of the events leading to tissue formation. Using a self-assembling bioactive matrix, we demonstrate the ability to induce ectopic formation of enamel at chosen sites adjacent to a mouse incisor cultured in vivo under the kidney capsule. The resulting material reveals the highly organized, hierarchical structure of hydroxyapatite crystallites similar to native enamel. This artificially triggered formation of organized mineral demonstrates a pathway for developing cell fabricated materials for treatment of dental caries, the most ubiquitous disease in man. Additionally, the artificial matrix provides a unique tool to probe cellular mechanisms involved in tissue formation further enabling the development of tooth organ replacements.

  18. Acanthamoeba induces cell-cycle arrest in host cells.

    Science.gov (United States)

    Sissons, James; Alsam, Selwa; Jayasekera, Samantha; Kim, Kwang Sik; Stins, Monique; Khan, Naveed Ahmed

    2004-08-01

    Acanthamoeba can cause fatal granulomatous amoebic encephalitis (GAE) and eye keratitis. However, the pathogenesis and pathophysiology of these emerging diseases remain unclear. In this study, the effects of Acanthamoeba on the host cell cycle using human brain microvascular endothelial cells (HBMEC) and human corneal epithelial cells (HCEC) were determined. Two isolates of Acanthamoeba belonging to the T1 genotype (GAE isolate) and T4 genotype (keratitis isolate) were used, which showed severe cytotoxicity on HBMEC and HCEC, respectively. No tissue specificity was observed in their ability to exhibit binding to the host cells. To determine the effects of Acanthamoeba on the host cell cycle, a cell-cycle-specific gene array was used. This screened for 96 genes specific for host cell-cycle regulation. It was observed that Acanthamoeba inhibited expression of genes encoding cyclins F and G1 and cyclin-dependent kinase 6, which are proteins important for cell-cycle progression. Moreover, upregulation was observed of the expression of genes such as GADD45A and p130 Rb, associated with cell-cycle arrest, indicating cell-cycle inhibition. Next, the effect of Acanthamoeba on retinoblastoma protein (pRb) phosphorylation was determined. pRb is a potent inhibitor of G1-to-S cell-cycle progression; however, its function is inhibited upon phosphorylation, allowing progression into S phase. Western blotting revealed that Acanthamoeba abolished pRb phosphorylation leading to cell-cycle arrest at the G1-to-S transition. Taken together, these studies demonstrated for the first time that Acanthamoeba inhibits the host cell cycle at the transcriptional level, as well as by modulating pRb phosphorylation using host cell-signalling mechanisms. A complete understanding of Acanthamoeba-host cell interactions may help in developing novel strategies to treat Acanthamoeba infections.

  19. Restoration of the Severely Decayed Tooth Using Crown Lengthening with Simultaneous Tooth-Preparation

    OpenAIRE

    2010-01-01

    This clinical case describes a treatment approach that combines, in a single appointment, a crown lengthening procedure and the final crown preparation for the restoration of a severely decayed tooth. This approach allows for a more accurate placement of the crown margin in relation to the bone crest while reducing treatment time.

  20. Restoration of the severely decayed tooth using crown lengthening with simultaneous tooth-preparation.

    Science.gov (United States)

    Park, Jun-Beom

    2010-04-01

    This clinical case describes a treatment approach that combines, in a single appointment, a crown lengthening procedure and the final crown preparation for the restoration of a severely decayed tooth. This approach allows for a more accurate placement of the crown margin in relation to the bone crest while reducing treatment time.

  1. Dux4 induces cell cycle arrest at G1 phase through upregulation of p21 expression

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Hongliang; Wang, Zhaoxia; Jin, Suqin; Hao, Hongjun [Department of Neurology, Peking University First Hospital, Beijing 100034 (China); Zheng, Lemin [The Institute of Cardiovascular Sciences, Peking University Health Science Center, Key Laboratory of Molecular Cardiovascular Sciences of Education Ministry, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides of Health Ministry, Beijing 100191 (China); Zhou, Boda [The Department of Cardiology, Peking University Third Hospital, Beijing 100191 (China); Zhang, Wei; Lv, He [Department of Neurology, Peking University First Hospital, Beijing 100034 (China); Yuan, Yun, E-mail: yuanyun2002@sohu.com [Department of Neurology, Peking University First Hospital, Beijing 100034 (China)

    2014-03-28

    Highlights: • Dux4 induced TE671 cell proliferation defect and G1 phase arrest. • Dux4 upregulated p21 expression without activating p53. • Silencing p21 rescued Dux4 mediated proliferation defect and cell cycle arrest. • Sp1 binding site was required for Dux4-induced p21 promoter activation. - Abstract: It has been implicated that Dux4 plays crucial roles in development of facioscapulohumeral dystrophy. But the underlying myopathic mechanisms and related down-stream events of this retrogene were far from clear. Here, we reported that overexpression of Dux4 in a cell model TE671 reduced cell proliferation rate, and increased G1 phase accumulation. We also determined the impact of Dux4 on p53/p21 signal pathway, which controls the checkpoint in cell cycle progression. Overexpression of Dux4 increased p21 mRNA and protein level, while expression of p53, phospho-p53 remained unchanged. Silencing p21 rescued Dux4 mediated proliferation defect and cell cycle arrest. Furthermore, we demonstrated that enhanced Dux4 expression increased p21 promoter activity and elevated expression of Sp1 transcription factor. Mutation of Sp1 binding site decreased dux4 induced p21 promoter activation. Chromatin immunoprecipitation (ChIP) assays confirmed the Dux4-induced binding of Sp1 to p21 promoter in vivo. These results suggest that Dux4 might induce proliferation inhibition and G1 phase arrest through upregulation of p21.

  2. Side effects of external tooth bleaching

    DEFF Research Database (Denmark)

    E.M., Bruzell; Pallesen, Ulla; Thoresen, N.R.

    2013-01-01

    -office = 39.3% [n = 28]; p >0.05; 95% CI [OR]: 0.198‑1.102) whereas prevalence of gingival irritation was higher after in-office treatment (at-home = 14.0%; in-office = 35.7%; p ... attributed to the bleaching treatment in the at-home and in-office groups, respectively. Predictors for side effects were tooth sensitivity, surface loss and gingivitis when observed at inclusion. Treatment-related predictors were bleaching concentration and contact between tray and gingiva. Conclusions...

  3. Dental histology of Coelophysis bauri and the evolution of tooth attachment tissues in early dinosaurs.

    Science.gov (United States)

    Fong, Raymond K M; LeBlanc, Aaron R H; Berman, David S; Reisz, Robert R

    2016-07-01

    Studies of dinosaur teeth have focused primarily on external crown morphology and thus, use shed or in situ tooth crowns, and are limited to the enamel and dentine dental tissues. As a result, the full suites of periodontal tissues that attach teeth to the jaws remain poorly documented, particularly in early dinosaurs. These tissues are an integral part of the tooth and thus essential to a more complete understanding of dental anatomy, development, and evolution in dinosaurs. To identify the tooth attachment tissues in early dinosaurs, histological thin sections were prepared from the maxilla and dentary of a partial skull of the early theropod Coelophysis bauri from the Upper Triassic (Rhaetian- 209-201 Ma) Whitaker Quarry, New Mexico, USA. As one of the phylogenetically and geologically oldest dinosaurs, it is an ideal candidate for examining dental tissues near the base of the dinosaurian clade. The teeth of C. bauri exhibited a fibrous tooth attachment in which the teeth possessed five tissues: enamel, dentine, cementum, periodontal ligament (PDL), and alveolar bone. Our findings, coupled with those of more recent studies of ornithischian teeth, indicate that a tripartite periodontium, similar to that of crocodilians and mammals, is the plesiomorphic condition for dinosaurs. The occurrence of a tripartite periodontium in dinosaurs adds to the growing consensus that the presence of these tissues is the plesiomorphic condition for the major amniote clades. Furthermore, this study establishes the relative timing of tissue development and growth directions of periodontal tissues and provides the first comparative framework for future studies of dinosaur periodontal development, tooth replacement, and histology. J. Morphol. 277:916-924, 2016. © 2016 Wiley Periodicals, Inc.

  4. Relationship between Intrauterine Bacterial Infection and Early Embryonic Developmental Arrest

    Institute of Scientific and Technical Information of China (English)

    Shao-Fei Yan; Xin-Yan Liu; Yun-Fei Cheng; Zhi-Yi Li; Jie Ou; Wei Wang; Feng-Qin Li

    2016-01-01

    Background:Early embryonic developmental arrest is the most commonly understudied adverse outcome of pregnancy.The relevance of intrauterine infection to spontaneous embryonic death is rarely studied and remains unclear.This study aimed to investigate the relationship between intrauterine bacterial infection and early embryonic developmental arrest.Methods:Embryonic chorion tissue and uterine swabs for bacterial detection were obtained from 33 patients who underwent artificial abortion (control group) and from 45 patients who displayed early embryonic developmental arrest (trial group).Results:Intrauterine bacterial infection was discovered in both groups.The infection rate was 24.44% (11/45) in the early embryonic developmental arrest group and 9.09% (3/33) in the artificial abortion group.Classification analysis revealed that the highest detection rate for Micrococcus luteus in the early embryonic developmental arrest group was 13.33% (6/45),and none was detected in the artificial abortion group.M.luteus infection was significantly different between the groups (P < 0.05 as shown by Fisher's exact test).In addition,no correlation was found between intrauterine bacterial infection and history of early embryonic developmental arrest.Conclusions:M.luteus infection is related to early embryonic developmental arrest and might be one of its causative factors.

  5. Ins-4 and daf-28 function redundantly to regulate C. elegans L1 arrest.

    Science.gov (United States)

    Chen, Yutao; Baugh, L Ryan

    2014-10-15

    Caenorhabditis elegans larvae reversibly arrest development in the first larval stage in response to starvation (L1 arrest or L1 diapause). Insulin-like signaling is a critical regulator of L1 arrest. However, the C. elegans genome encodes 40 insulin-like peptides, and it is unknown which peptides participate in nutritional control of L1 development. Work in other contexts has revealed that insulin-like genes can promote development ("agonists") or developmental arrest ("antagonists"), suggesting that such agonists promote L1 development in response to feeding. We measured mRNA expression dynamics with high temporal resolution for all 40 insulin-like genes during entry into and recovery from L1 arrest. Nutrient availability influences expression of the majority of insulin-like genes, with variable dynamics suggesting complex regulation. We identified thirteen candidate agonists and eight candidate antagonists based on expression in response to nutrient availability. We selected ten candidate agonists (daf-28, ins-3, ins-4, ins-5, ins-6, ins-7, ins-9, ins-26, ins-33 and ins-35) for further characterization in L1 stage larvae. We used destabilized reporter genes to determine spatial expression patterns. Expression of candidate agonists is largely overlapping in L1 stage larvae, suggesting a role of the intestine, chemosensory neurons ASI and ASJ, and the interneuron PVT in control of L1 development. Transcriptional regulation of candidate agonists is most significant in the intestine, as if internal nutrient status is a more important influence on transcription than sensory perception. Phenotypic analysis of single and compound deletion mutants did not reveal effects on L1 developmental dynamics, though simultaneous disruption of ins-4 and daf-28 increases survival of L1 arrest. Furthermore, overexpression of ins-4, ins-6 or daf-28 alone decreases survival and promotes cell division during starvation. These results suggest extensive functional overlap among insulin

  6. Inadvertent tooth movement with fixed lingual retainers.

    Science.gov (United States)

    Shaughnessy, Timothy G; Proffit, William R; Samara, Said A

    2016-02-01

    Fixed retainers are effective in maintaining the alignment of the anterior teeth more than 90% of the time, but they can produce inadvertent tooth movement that in the most severe instances requires orthodontic retreatment managed with a periodontist. This is different from relapse into crowding when a fixed retainer is lost. These problems arise when the retainer breaks but remains bonded to some or all teeth, or when an intact retainer is distorted by function or was not passive when bonded. In both instances, torque of the affected teeth is the predominant outcome. A fixed retainer made with dead soft wire is the least likely to create torque problems but is the most likely to break. Highly flexible twist wires bonded to all the teeth appear to be the most likely to produce inadvertent tooth movement, but this also can occur with stiffer wires bonded only to the canines. Orthodontists, general dentists, and patients should be aware of possible problems with fixed retainers, especially those with all teeth bonded, because the patient might not notice partial debonding. Regular observations of patients wearing fixed retainers by orthodontists in the short term and family dentists in the long term are needed.

  7. Hierarchical structure and biomineralization in cricket tooth

    CERN Document Server

    Xing, Xueqing; Cai, Quan; Mo, Guang; Du, Rong; Chen, Zhongjun; Wu, Zhonghua

    2012-01-01

    Cricket is a truculent insect with stiff and sharp teeth as a fighting weapon. The structure and possible biomineralization of the cricket teeth are always interested. Synchrotron radiation X-ray fluorescence, X-ray diffraction and small angle X-ray scattering techniques were used to probe the element distribution, possible crystalline structures and size distribution of scatterers in cricket teeth. Scanning electron microscope was used to observe the nanoscaled structure. The results demonstrate that Zn is the main heavy element in cricket teeth. The surface of the cricket teeth has a crystalline compound like ZnFe2(AsO4)2(OH)2(H2O)4. While, the interior of the teeth has a crystalline compound like ZnCl2, which is from the biomineralization. The ZnCl2-like biomineral forms nanoscaled microfibrils and their axial direction points at the top of tooth cusp. The microfibrils aggregate random into intermediate filaments, forming a hierarchical structure. A sketch map of the cricket tooth cusp was proposed and a d...

  8. Massive clot formation after tooth extraction

    Directory of Open Access Journals (Sweden)

    Santosh Hunasgi

    2015-01-01

    Full Text Available Oral surgical procedures mainly tooth extraction can be related with an extended hemorrhage owed to the nature of the process resulting in an "open wound." The attempt of this paper is to present a case of massive postoperative clot formation after tooth extraction and highlight on the oral complications of surgical procedures. A 32-year-old male patient reported to the Dental Clinic for evaluation and extraction of grossly decayed 46. Clinical evaluation of 46 revealed root stumps. Extraction of the root stumps was performed, and it was uneventful. Hemostasis was achieved and postsurgical instructions were specified to the patient. The patient reported to the clinic, the very subsequent morning with a criticism of bleeding at the extraction site. On clinical examination, bleeding was noted from the socket in relation to 46. To control bleeding, oral hemostatic drugs Revici - E (Ethamsylate 500 mg was prescribed and bleeding was stopped in 2 h. However, a massive clot was formed at the extraction site. Further, this clot resolved on its own in 1-week time. Despite the fact that dental extraction is considered to be a minor surgical procedure, some cases may present with life-threatening complications including hemorrhage. Vigilant and significant history taking, physical and dental examinations prior to dental procedures are a must to avoid intraoperative and postoperative complications.

  9. Iatrogenic nasolacrimal duct obstruction following tooth extraction in a cat.

    Science.gov (United States)

    Paiva, Sávia Calline C S; Froes, Tilde R; Lange, Rogério Ribas; Machado, Marcello; Pachaly, José Ricardo; Montiani-Ferreira, Fabiano

    2013-01-01

    A 10-year-old DSH cat was referred for a dental evaluation and extraction procedure. Subsequently, the animal developed an acute onset of ocular discharge. Ophthalmologic examination revealed presence of unilateral ocular mucoid discharge leading to a diagnosis of epiphora secondary to nasolacrimal duct obstruction. Dacryocystorhinography was performed and confirmed the presence of a nasolacrimal duct obstruction, presumably acquired after an invasive dental procedure. Additionally, a vinyl cast in situ study of the nasolacrymal apparatus was performed to demonstrate the route of the nasolacrimal duct in the cat and its relationship to oral dental structures. This report documents an unusual case in which excessive inflammation/edema following tooth extraction caused acute epiphora secondary to extraluminal compression of the distal nasolacrimal duct.

  10. 3D Simulation Modeling of the Tooth Wear Process.

    Science.gov (United States)

    Dai, Ning; Hu, Jian; Liu, Hao

    2015-01-01

    Severe tooth wear is the most common non-caries dental disease, and it can seriously affect oral health. Studying the tooth wear process is time-consuming and difficult, and technological tools are frequently lacking. This paper presents a novel method of digital simulation modeling that represents a new way to study tooth wear. First, a feature extraction algorithm is used to obtain anatomical feature points of the tooth without attrition. Second, after the alignment of non-attrition areas, the initial homogeneous surface is generated by means of the RBF (Radial Basic Function) implicit surface and then deformed to the final homogeneous by the contraction and bounding algorithm. Finally, the method of bilinear interpolation based on Laplacian coordinates between tooth with attrition and without attrition is used to inversely reconstruct the sequence of changes of the 3D tooth morphology during gradual tooth wear process. This method can also be used to generate a process simulation of nonlinear tooth wear by means of fitting an attrition curve to the statistical data of attrition index in a certain region. The effectiveness and efficiency of the attrition simulation algorithm are verified through experimental simulation.

  11. 3D Simulation Modeling of the Tooth Wear Process.

    Directory of Open Access Journals (Sweden)

    Ning Dai

    Full Text Available Severe tooth wear is the most common non-caries dental disease, and it can seriously affect oral health. Studying the tooth wear process is time-consuming and difficult, and technological tools are frequently lacking. This paper presents a novel method of digital simulation modeling that represents a new way to study tooth wear. First, a feature extraction algorithm is used to obtain anatomical feature points of the tooth without attrition. Second, after the alignment of non-attrition areas, the initial homogeneous surface is generated by means of the RBF (Radial Basic Function implicit surface and then deformed to the final homogeneous by the contraction and bounding algorithm. Finally, the method of bilinear interpolation based on Laplacian coordinates between tooth with attrition and without attrition is used to inversely reconstruct the sequence of changes of the 3D tooth morphology during gradual tooth wear process. This method can also be used to generate a process simulation of nonlinear tooth wear by means of fitting an attrition curve to the statistical data of attrition index in a certain region. The effectiveness and efficiency of the attrition simulation algorithm are verified through experimental simulation.

  12. [Tooth decay and its complication prognosis in smokers].

    Science.gov (United States)

    Orekhova, L Iu; Osipova, M V

    2014-01-01

    The study focuses on complicated and non-complicated tooth decay course and prognosis in smokers. Oral status, prevention and treatment effectiveness was assessed in 330 non-smokers and 345 smoking patients. The results allowed concluding with guidelines for tooth decay prevention and treatment in smokers.

  13. Severe tooth wear: European consensus statement on management guidelines

    DEFF Research Database (Denmark)

    Loomans, Bas AC; Attin, Thomas; Opdam, Niek JM;

    2016-01-01

    This paper reports a European expert consensus statement on guidelines for the management of severe tooth wear. It focuses on the definition of physiological versus pathological tooth wear and recommends diagnosis, monitoring and counseling to define the activity of the wear. Restorative interven...

  14. The Prevalence of Tooth Wear in the Dutch Adult Population

    NARCIS (Netherlands)

    Wetselaar, Peter; Vermaire, Jan H; Visscher, Corine M; Lobbezoo, Frank; Schuller, Annemarie A

    2016-01-01

    This study aimed to assess the prevalence of tooth wear in different age groups of the Dutch adult population and to determine this tooth wear distribution by gender, socioeconomic class, and type of teeth. Results were compared with the outcomes of a previous study in a comparable population. As pa

  15. Anomalies of tooth formation in hypohidrotic ectodermal dysplasia

    DEFF Research Database (Denmark)

    Lexner, Michala O; Bardow, Allan; Hertz, Jens Michael;

    2007-01-01

    is the first to elaborate on anomalies of tooth formation found in a group of hemizygous males and heterozygous females with known ED1 mutations. These tooth anomalies may be used as dental biomarkers for heterozygous females, enabling an earlier diagnosis, and therefore, better treatment and genetic...

  16. Pollution performance of 110 kV metal oxide arresters

    Energy Technology Data Exchange (ETDEWEB)

    Chrzan, K.; Pohl, Z. [Technical Univ. of Wroclaw (Poland). Dept. of Electrical Engineering; Grzybowski, S. [Mississippi State Univ., MS (United States). Dept. of Electrical and Computer Engineering; Koehler, W. [Univ. of Stuttgart (Germany). Dept. of Electrical Engineering

    1997-04-01

    Pollution test results of single unit 110 kV metal oxide surge arresters with porcelain housing according to the solid layer and salt fog methods are presented. During 6 hours of testing, the internal and external charge and maximum temperature along the varistor column were measured. The formation of single stable dry bands on the housing was often observed, especially during salt fog tests. In such cases, the varistor temperature can reach about 70 C. The simple electrical model of the arrester enabling calculations of voltages and currents as a function of arrester and pollution parameters is shown.

  17. Evolution of the dragonfly head-arresting system

    OpenAIRE

    Gorb, S. N.

    1999-01-01

    The arrester or fixation system of the head in adult Odonata is unique among arthropods. This system involves the organs of two body segments: the head and the neck. It consists of a skeleton–muscle apparatus that sets the arrester parts in motion. The parts comprise formations covered with complicated microstructures: fields of microtrichia on the rear surface of the head and post-cervical sclerites of the neck. The arrester immobilizes the head during feeding or when the dragonfly is in tan...

  18. Altered Cell Cycle Arrest by Multifunctional Drug-Loaded Enzymatically-Triggered Nanoparticles.

    Science.gov (United States)

    Huang, Can; Sun, Ying; Shen, Ming; Zhang, Xiangyu; Gao, Pei; Duan, Yourong

    2016-01-20

    cRGD-targeting matrix metalloproteinase (MMP)-sensitive nanoparticles [PLGA-PEG1K-cRGD/PLGA-peptide-PEG5K (NPs-cRGD)] were successfully developed. Au-Pt(IV) nanoparticles, PTX, and ADR were encapsulated into NPs-RGD separately. The effects of the drug-loaded nanoparticles on the cell cycle were investigated. Here, we showed that higher cytotoxicity of drug-loaded nanoparticles was related to the cell cycle arrest, compared to that of free drugs. The NPs-cRGD studied here did not disrupt cell cycle progression. The cell cycle of Au-Pt(IV)@NPs-cRGD showed a main S phase arrest in all phases of the cell cycle phase, especially in G0/G1 phase. PTX@NPs-cRGD and ADR@NPs-cRGD showed a higher ratio of G2/M and S phase arrest than the free drugs, respectively. Cells in G0/G1 and S phases of the cell cycle had a higher uptake ratio of NPs-cRGD. A nutrient deprivation or an increase in the requirement of nutrients in tumor cells could promote the uptake of nanoparticles from the microenvironments. In vivo, NPs-cRGD could efficiently accumulate at tumor sites. The inhibition of tumor growth coupled with cell cycle arrest is in line with that in vitro. On the basis of our results, we propose that future studies on nanoparticle action mechanism should consider the cell cycle, which could be different from free drugs. Understanding the actions of cell cycle arrest could affect the application of nanomedicine in the clinic.

  19. Crowned spur gears - Methods for generation and tooth contact analysis. I - Basic concepts, generation of the pinion tooth surface by a plane

    Science.gov (United States)

    Litvin, F. L.; Handschuh, R. F.; Zhang, J.

    1988-01-01

    A topology of crowned spur pinion tooth surface that reduces the level of transmission errors due to misalignment is proposed. The geometry of the deviated pinion tooth surface and regular gear tooth surface, along with tooth contact analysis is discussed. Generation of the deviated pinion tooth surface by a plane whose motion is controlled by a five-degree-of-freedom system is proposed. Numerical results are included and indicate that transmission errors remain low as the gears are misaligned.

  20. A predictive model to identify patients with suspected acute coronary syndromes at high risk of cardiac arrest or in-hospital mortality: An IMMEDIATE Trial sub-study

    Directory of Open Access Journals (Sweden)

    Madhab Ray

    2015-12-01

    Conclusions: The multivariable predictive model developed identified patients with very early ACS at high risk of cardiac arrest or death. Using this model could assist treating those with greatest potential benefit from GIK.

  1. An Analysis of the Symptomatic Domains Most Relevant to Charcot Marie Tooth Neuropathy (CMT) Patients

    Science.gov (United States)

    2015-04-28

    Charcot Marie Tooth Disease (CMT); Hereditary Sensory and Motor Neuropathy; Nerve Compression Syndromes; Tooth Diseases; Congenital Abnormalities; Genetic Diseases, Inborn; Heredodegenerative Disorders, Nervous System

  2. A Rasch Analysis of the Charcot-Marie-Tooth Neuropathy Score (CMTNS) in a Cohort of Charcot-Marie-Tooth Type 1A Patients

    Science.gov (United States)

    Guedj, Mickaël; Bertrand, Viviane; Foucquier, Julie; Jouve, Elisabeth; Commenges, Daniel; Proust-Lima, Cécile; Murphy, Niall P.; Blin, Olivier; Magy, Laurent; Cohen, Daniel; Attarian, Shahram

    2017-01-01

    The Charcot-Marie-Tooth Neuropathy Score (CMTNS) was developed as a main efficacy endpoint for application in clinical trials of Charcot-Marie-Tooth disease type 1A (CMT1A). However, the sensitivity of the CMTNS for measuring disease severity and progression in CMT1A patients has been questioned. Here, we applied a Rasch analysis in a French cohort of patients to evaluate the psychometrical properties of the CMTNS. Overall, our analysis supports the validity of the CMTNS for application to CMT1A patients though with some limitations such as certain items of the CMTNS being more suitable for moderate to severe forms of the disease, and some items being disordered. We suggest that additional items and/or categories be considered to better assess mild-to-moderate patients. PMID:28095456

  3. Neurological and circulatory outcomes of cardiopulmonary resuscitation in progress: influence of pre-arrest and arrest factors.

    Science.gov (United States)

    Jørgensen, E O

    1998-01-01

    Possible correlations between the circulatory and neurological responses to cardiopulmonary resuscitation (CPR) and the influence of pre-arrest factors (demographic data, medical history and aetiology of circulatory arrest) and arrest factors (location of arrest, ECG configurations, and duration of resuscitation) on the course of circulatory and neurological recovery were investigated in 111 victims of circulatory arrest. At the start of resuscitation 57 patients (Group I) had some brain function and 54 (Group II) had no brain function. Sixty nine patients (62%) had circulation restored but 54 (78%) were left with heart failure. Forty one patients (39%) survived the first day, 26 (63%) with heart failure; only 34 (31%) were alive after 48 h, 17 (50%) with heart failure. Half of the patients surviving 24 or 48 h had awakened. Consciousness returned in 32 patients (29%) during the first 48 h, more frequently in Group I than in Group II. Patients in Group I had a higher incidence of in-hospital arrest and had their circulation restored more often than those in Group II. Survival and post-resuscitation heart failure was alike in the groups. The pre-arrest factors explored did not modify the circulatory or neurological outcome whereas initial ventricular fibrillation was significantly related to recovery of consciousness. The revivability of spontaneous circulation and of neurological functions was found thus mainly to be determined by global ischaemia sustained prior to and during CPR.

  4. Reattachment of complicated tooth fracture: An alternative approach

    Directory of Open Access Journals (Sweden)

    Nujella B. P. Surya Kumari

    2012-01-01

    Full Text Available Trauma to the anterior teeth is relatively a common occurrence. There are several treatment modalities for such condition, one of which is reattachment of fractured fragment itself. Reattachment of fractured fragment provides immediate treatment with better esthetics, restoration of function, and is a faster and less complicated procedure. Reattachment of tooth fragment should be the first choice and is a viable alternative to conventional approaches because of simplicity, natural esthetics, and conservation of tooth structure. Patient cooperation and understanding of the limitations of the treatment is of utmost importance for good prognosis.The present case report describes management of a complicated fracture of maxillary right central incisor treated endodontically, followed by reattachment of the same fragment. Reattachment of fractured tooth fragments offers a viable restorative alternative, immediately restores tooth function for the clinician because it restores tooth function and esthetics with the use of a very conservative and cost-effective approach.

  5. Initial observations of cheek tooth abnormalities in sheep in Slovenia.

    Science.gov (United States)

    Erjavec, V; Crossley, D

    2010-07-24

    Observations were made on a small flock of 50 sheep of the native Slovenian Jezersko-Solcava breed by investigators with dental training. The aim was to determine the range of naturally occurring dental diseases, so postmortem examinations were performed on animals slaughtered for meat or culled due to disease. Additional data were obtained by examination of 25 specimens submitted for investigation of unexplained death at a pathology centre. Seventeen (34 per cent) of the flock had incisor disease but only five became clinically ill; all these five had advanced cheek tooth disease (gingival recession, periodontal pocketing, diastemata, missing teeth, occlusal wear abnormalities, food impaction, tooth mobility, tooth fracture, tooth loss and/or jaw abscessation). Advanced cheek tooth disease was found in 21 (84 per cent) of the sheep submitted to the pathology laboratory, while only seven (28 per cent) had advanced incisor disease. The results show that, as in other countries, dental disease is a serious problem for sheep in Slovenia.

  6. Signaling networks regulating tooth organogenesis and regeneration, and the specification of dental mesenchymal and epithelial cell lineages.

    Science.gov (United States)

    Jussila, Maria; Thesleff, Irma

    2012-04-01

    Teeth develop as ectodermal appendages from epithelial and mesenchymal tissues. Tooth organogenesis is regulated by an intricate network of cell-cell signaling during all steps of development. The dental hard tissues, dentin, enamel, and cementum, are formed by unique cell types whose differentiation is intimately linked with morphogenesis. During evolution the capacity for tooth replacement has been reduced in mammals, whereas teeth have acquired more complex shapes. Mammalian teeth contain stem cells but they may not provide a source for bioengineering of human teeth. Therefore it is likely that nondental cells will have to be reprogrammed for the purpose of clinical tooth regeneration. Obviously this will require understanding of the mechanisms of normal development. The signaling networks mediating the epithelial-mesenchymal interactions during morphogenesis are well characterized but the molecular signatures of the odontogenic tissues remain to be uncovered.

  7. 高速铁路牵引供电接触网用带间隙避雷器的研制%Development of Metal Oxide Surge Arrester With Series Gap for Traction Power Supply System Catenary of High-speed Electrified Railway

    Institute of Scientific and Technical Information of China (English)

    边凯; 陈维江; 沈海滨; 李成榕; 王立天; 赵海军; 王彦利; 尹彬; 李庆余

    2013-01-01

    中国高速铁路线路高架桥路段比例大,且相对集中在雷电活动较强烈地区,牵引供电接触网雷击故障多,须采取措施加以解决.在接触网绝缘子旁并联安装带间隙避雷器是一种有效的防雷措施.根据接触网布局结构和运行可靠性要求高的特点,提出了一种与绝缘子一体化安装的避雷器分体结构型式,特别设计抱箍增强安装稳定性,提出了一种避雷器本体压力释了U型放结构可有效释放短路能量,研究选择了本体关键参数和串联间隙距离,确定了短路试验和振动试验方法和条件,对样品进行了雷电冲击放电伏秒特性试验、短路试验和振动试验,从而验证该技术性能的可靠性.最后,研制了适合接触网正馈线、接触线和加强线绝缘子使用的3种形式避雷器,并获国家发明专利授权,已在京沪高速铁路上试运行,状态良好.%In China, viaduct sections are widely adopted in high-speed electrified railway lines and most of the lines go through strong lightning activity areas. This leads to high lightning stroke failure rate of traction power supply catenary. To install metal oxide surge arrester with series gap(GMOA) parallel with insulators is an ideal lightning protection measure to solve the problem. In the paper, a kind of arrester and insulator integral mounting structure type was put forward, U-shaped clamp was specially designed to enhance the stability of the installation, an arrester body pressure release structure was presented to release the short-circuit energy effectively, the primary parameters of MOA body and the distance of series gap were selected, the test methods and conditions of short-circuit test and vibration test were provided, and the samples proved reliable by the results of lightning impulse test .short-circuit current test and vibration test. Three kinds of GMOA products with positive feeder/contact wire/strengthened contact wire insulators were

  8. Cardiac arrest upon induction of anesthesia in children with cardiomyopathy: an analysis of incidence and risk factors.

    LENUS (Irish Health Repository)

    Lynch, Johanne

    2012-02-01

    INTRODUCTION: It is thought that patients with cardiomyopathy have an increased risk of cardiac arrest on induction of anesthesia, but there is little available data. The purpose of this study was to identify the incidence and potential risk factors for cardiac arrest upon induction of anesthesia in children with cardiomyopathy in our institution. METHODS: A retrospective chart review was performed. Eligible patients included patients admitted between 1998 and 2008 with the International Statistical Classification of Disease code for cardiomyopathy (ICD-9 code 425) who underwent airway intervention for sedation or general anesthesia in the operating room, cardiac diagnostic and interventional unit (CDIU) or intensive care unit. Patients undergoing emergency airway intervention following cardiovascular collapse were excluded. For each patient, we recorded patient demographics, disease severity, anesthesia location, and anesthetic technique. RESULTS: One hundred and twenty-nine patients with cardiomyopathy underwent a total of 236 anesthetic events, and four cardiac arrests were identified. One was related to bradycardia (HR<60), two were attributed to bradycardia in association with severe hypotension (systolic blood pressure<45), and the fourth arrest was related to isolated severe hypotension. Two occurred in the operating suite and two in the CDIU. There was no resulting mortality. One patient progressed to heart transplantation. Multiple combinations of anesthetic drugs were used for induction of anesthesia. CONCLUSION: We performed a review of the last 10 years of anesthesia events in children with cardiomyopathy. We report four cardiac arrests in two patients and 236 anesthetic events (1.7%). To the best of our knowledge, this is the largest review of these patients to date but is limited by its retrospective nature. The low cardiac arrest incidence prevents the identification of risk factors and the development of a cardiac arrest risk predictive clinical

  9. Modulation of medium pH by Caulobacter crescentus facilitates recovery from uranium-induced growth arrest.

    Science.gov (United States)

    Park, Dan M; Jiao, Yongqin

    2014-09-01

    The oxidized form of uranium [U(VI)] predominates in oxic environments and poses a major threat to ecosystems. Due to its ability to mineralize U(VI), the oligotroph Caulobacter crescentus is an attractive candidate for U(VI) bioremediation. However, the physiological basis for U(VI) tolerance is unclear. Here we demonstrated that U(VI) caused a temporary growth arrest in C. crescentus and three other bacterial species, although the duration of growth arrest was significantly shorter for C. crescentus. During the majority of the growth arrest period, cell morphology was unaltered and DNA replication initiation was inhibited. However, during the transition from growth arrest to exponential phase, cells with shorter stalks were observed, suggesting a decoupling between stalk development and the cell cycle. Upon recovery from growth arrest, C. crescentus proliferated with a growth rate comparable to that of a control without U(VI), although a fraction of these cells appeared filamentous with multiple replication start sites. Normal cell morphology was restored by the end of exponential phase. Cells did not accumulate U(VI) resistance mutations during the prolonged growth arrest, but rather, a reduction in U(VI) toxicity occurred concomitantly with an increase in medium pH. Together, these data suggest that C. crescentus recovers from U(VI)-induced growth arrest by reducing U(VI) toxicity through pH modulation. Our finding represents a unique U(VI) detoxification strategy and provides insight into how microbes cope with U(VI) under nongrowing conditions, a metabolic state that is prevalent in natural environments.

  10. Hybrid simulation of metal oxide surge-arrester thermal behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Huang, L.; Raghuveer, M.R. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Electrical and Computer Engineering

    1996-01-01

    A finite-difference-based technique for simulating the thermal behaviour of a metal oxide surge arrester (MOSA) was described. The improved hybrid thermal modelling technique was claimed to accurately represent heat-transfer modes. Fin theory was used to represent arrester sheds. The proposed model, which relies on simple measurements at the arrester terminals, yields the temporal variation of temperature in a MOSA in both the axial and radial direction. The thermal behaviour of a MOSA under steady-state and transient conditions can be simulated using such a model under different environmental conditions. The accuracy of the modelling technique was demonstrated experimentally by measurements conducted on an arrester. 15 refs., 7 figs.

  11. Endothelial Dysfunction in Resuscitated Cardiac Arrest (ENDO-RCA)

    DEFF Research Database (Denmark)

    Meyer, Anna Sina P; Ostrowski, Sisse R; Kjaergaard, Jesper;

    2016-01-01

    BACKGROUND: Morbidity and mortality following initial survival of cardiac arrest remain high despite great efforts to improve resuscitation techniques and post-resuscitation care, in part due to the ischemia-reperfusion injury secondary to the restoration of the blood circulation. Patients...... resuscitated from cardiac arrest display evidence of endothelial injury and coagulopathy (hypocoagulability, hyperfibrinolysis), which in associated with poor outcome. Recent randomized controlled trials have revealed that treatment with infusion of prostacyclin reduces endothelial damage after major surgery...... and AMI. Thus, a study is pertinent to investigate if prostacyclin infusion as a therapeutic intervention reduces endothelial damage without compromising, or even improving, the hemostatic competence in resuscitated cardiac arrest patients. Post-cardiac arrest patients frequently have a need...

  12. Arrest of cytoplasmic streaming induces algal proliferation in green paramecia.

    Directory of Open Access Journals (Sweden)

    Toshiyuki Takahashi

    Full Text Available A green ciliate Paramecium bursaria, bearing several hundreds of endosymbiotic algae, demonstrates rotational microtubule-based cytoplasmic streaming, in which cytoplasmic granules and endosymbiotic algae flow in a constant direction. However, its physiological significance is still unknown. We investigated physiological roles of cytoplasmic streaming in P. bursaria through host cell cycle using video-microscopy. Here, we found that cytoplasmic streaming was arrested in dividing green paramecia and the endosymbiotic algae proliferated only during the arrest of cytoplasmic streaming. Interestingly, arrest of cytoplasmic streaming with pressure or a microtubule drug also induced proliferation of endosymbiotic algae independently of host cell cycle. Thus, cytoplasmic streaming may control the algal proliferation in P. bursaria. Furthermore, confocal microscopic observation revealed that a division septum was formed in the constricted area of a dividing paramecium, producing arrest of cytoplasmic streaming. This is a first report to suggest that cytoplasmic streaming controls proliferation of eukaryotic cells.

  13. Imaging tooth enamel using zero echo time (ZTE) magnetic resonance imaging

    Science.gov (United States)

    Rychert, Kevin M.; Zhu, Gang; Kmiec, Maciej M.; Nemani, Venkata K.; Williams, Benjamin B.; Flood, Ann B.; Swartz, Harold M.; Gimi, Barjor

    2015-03-01

    In an event where many thousands of people may have been exposed to levels of radiation that are sufficient to cause the acute radiation syndrome, we need technology that can estimate the absorbed dose on an individual basis for triage and meaningful medical decision making. Such dose estimates may be achieved using in vivo electron paramagnetic resonance (EPR) tooth biodosimetry, which measures the number of persistent free radicals that are generated in tooth enamel following irradiation. However, the accuracy of dose estimates may be impacted by individual variations in teeth, especially the amount and distribution of enamel in the inhomogeneous sensitive volume of the resonator used to detect the radicals. In order to study the relationship between interpersonal variations in enamel and EPR-based dose estimates, it is desirable to estimate these parameters nondestructively and without adding radiation to the teeth. Magnetic Resonance Imaging (MRI) is capable of acquiring structural and biochemical information without imparting additional radiation, which may be beneficial for many EPR dosimetry studies. However, the extremely short T2 relaxation time in tooth structures precludes tooth imaging using conventional MRI methods. Therefore, we used zero echo time (ZTE) MRI to image teeth ex vivo to assess enamel volumes and spatial distributions. Using these data in combination with the data on the distribution of the transverse radio frequency magnetic field from electromagnetic simulations, we then can identify possible sources of variations in radiation-induced signals detectable by EPR. Unlike conventional MRI, ZTE applies spatial encoding gradients during the RF excitation pulse, thereby facilitating signal acquisition almost immediately after excitation, minimizing signal loss from short T2 relaxation times. ZTE successfully provided volumetric measures of tooth enamel that may be related to variations that impact EPR dosimetry and facilitate the development

  14. Mutations in the MORC2 gene cause axonal Charcot-Marie-Tooth disease.

    Science.gov (United States)

    Sevilla, Teresa; Lupo, Vincenzo; Martínez-Rubio, Dolores; Sancho, Paula; Sivera, Rafael; Chumillas, María J; García-Romero, Mar; Pascual-Pascual, Samuel I; Muelas, Nuria; Dopazo, Joaquín; Vílchez, Juan J; Palau, Francesc; Espinós, Carmen

    2016-01-01

    Charcot-Marie-Tooth disease (CMT) is a complex disorder with wide genetic heterogeneity. Here we present a new axonal Charcot-Marie-Tooth disease form, associated with the gene microrchidia family CW-type zinc finger 2 (MORC2). Whole-exome sequencing in a family with autosomal dominant segregation identified the novel MORC2 p.R190W change in four patients. Further mutational screening in our axonal Charcot-Marie-Tooth disease clinical series detected two additional sporadic cases, one patient who also carried the same MORC2 p.R190W mutation and another patient that harboured a MORC2 p.S25L mutation. Genetic and in silico studies strongly supported the pathogenicity of these sequence variants. The phenotype was variable and included patients with congenital or infantile onset, as well as others whose symptoms started in the second decade. The patients with early onset developed a spinal muscular atrophy-like picture, whereas in the later onset cases, the initial symptoms were cramps, distal weakness and sensory impairment. Weakness and atrophy progressed in a random and asymmetric fashion and involved limb girdle muscles, leading to a severe incapacity in adulthood. Sensory loss was always prominent and proportional to disease severity. Electrophysiological studies were consistent with an asymmetric axonal motor and sensory neuropathy, while fasciculations and myokymia were recorded rather frequently by needle electromyography. Sural nerve biopsy revealed pronounced multifocal depletion of myelinated fibres with some regenerative clusters and occasional small onion bulbs. Morc2 is expressed in both axons and Schwann cells of mouse peripheral nerve. Different roles in biological processes have been described for MORC2. As the silencing of Charcot-Marie-Tooth disease genes have been associated with DNA damage response, it is tempting to speculate that a deregulation of this pathway may be linked to the axonal degeneration observed in MORC2 neuropathy, thus adding a

  15. In vitro differentiation and attachment of human embryonic stem cells on periodontal tooth root surfaces.

    Science.gov (United States)

    Inanç, Bülend; Elçin, A Eser; Elçin, Y Murat

    2009-11-01

    Periodontal tissue engineering based on cell replacement therapies is a promising field for improved regeneration of tooth supporting structures lost as a result of destructive periodontal diseases. Human embryonic stem cells (hESCs) could become adequate cell source for tissue engineering because of their unlimited proliferative potential and ability to differentiate to all somatic cell types. The aim of this study was to analyze the differentiation capacity of hESCs toward periodontal compartment cells and their relationship with tooth root surfaces in vitro. Periodontal ligament fibroblastic cell (PDLF) cultures were established and characterized; hESCs (HUES-9 line) were expanded in undifferentiated state and characterized for pluripotency morphologically and immunohistochemically. Extracted tooth root slices (RS) of 300 microm thickness, prepared with both periodontal and endodontic instrumentation, were used. Three different experimental groups were established: (i) undifferentiated hESC colonies cultured on and around the RS; (ii) undifferentiated hESC colonies cultured on and around RS with PDLF coculture, and (iii) undifferentiated hESC colonies cultured on and around RS with PDLF coculture in osteoinductive medium for 3 weeks. The fibrogenic and osteogenic marker expression was assessed with immunohistochemistry; histological staining and scanning electron microscopy were utilized to determine the relationship between differentiating hESCs and mineralized tooth root structures. Results demonstrate that hESC differentiation is influenced by tooth structures, PDLFs, and osteogenic medium, resulting with increased propensity toward mesenchymal lineage commitment, and formation of soft-hard tissue relationship in close contact areas. The proposed experimental system may facilitate further understanding in development of periodontal structures and contribute to realization of hESCs as a cell source in periodontal tissue engineering applications.

  16. Platelet Rich Fibrin in the revitalization of tooth with necrotic pulp and open apex

    Directory of Open Access Journals (Sweden)

    Vasundara Yayathi Shivashankar

    2012-01-01

    Full Text Available Regeneration of pulp-dentin complex in an infected necrotic tooth with an open apex is possible if the canal is effectively disinfected. The purpose of this case report is to add a regenerative endodontic case to the existing literature about using Platelet Rich Fibrin (PRF. A nine year old boy who accidently broke his immature maxillary central incisor tooth, developed pulpal necrosis with apical periodontitis. After the access cavity preparation, the canal was effectively irrigated with 20 ml of 5.25% sodium hypochlorite solution and 10ml of 0.2% chlorhexidine solution and dried with paper points. Triple antibiotic paste was placed inside the canal and left for 21 days. 12 ml of whole blood was drawn from the patient′s right antecubital vein and centrifuged for 10 minutes to obtain the Choukroun′s PRF. After the removal of the triple antibiotic paste, the PRF was placed into the canal till the level of cementoenamel junction and 3mm of grey MTA was placed directly over the PRF clot. The setting of MTA was confirmed 3 days later and the tooth was double sealed with GIC and Composite restoration.After 1 year the clinical examination revealed negative responses to percussion and palpation tests. The tooth responded positively to cold and electric pulp tests. Radiographic examination revealed continued thickening of the dentinal walls, root lengthening, regression of the periapical lesion and apical closure. On the basis of the results obtained in our case report we conclude that revitalization of necrotic infected immature tooth is possible under conditions of total canal disinfection and PRF is an ideal biomaterial for pulp-dentin complex regeneration.

  17. Procedure for Tooth Contact Analysis of a Face Gear Meshing With a Spur Gear Using Finite Element Analysis

    Science.gov (United States)

    Bibel, George; Lewicki, David G. (Technical Monitor)

    2002-01-01

    A procedure was developed to perform tooth contact analysis between a face gear meshing with a spur pinion using finite element analysis. The face gear surface points from a previous analysis were used to create a connected tooth solid model without gaps or overlaps. The face gear surface points were used to create a five tooth face gear Patran model (with rim) using Patran PCL commands. These commands were saved in a series of session files suitable for Patran input. A four tooth spur gear that meshes with the face gear was designed and constructed with Patran PCL commands. These commands were also saved in a session files suitable for Patran input. The orientation of the spur gear required for meshing with the face gear was determined. The required rotations and translations are described and built into the session file for the spur gear. The Abaqus commands for three-dimensional meshing were determined and verified for a simplified model containing one spur tooth and one face gear tooth. The boundary conditions, loads, and weak spring constraints were determined to make the simplified model work. The load steps and load increments to establish contact and obtain a realistic load was determined for the simplified two tooth model. Contact patterns give some insight into required mesh density. Building the two gears in two different local coordinate systems and rotating the local coordinate systems was verified as an easy way to roll the gearset through mesh. Due to limitation of swap space, disk space and time constraints of the summer period, the larger model was not completed.

  18. Usage of Lightning Arrester Line to Feed Light Electrical Loads

    Directory of Open Access Journals (Sweden)

    Hani B. Odeh

    2009-01-01

    Full Text Available In remote areas, light loads (tens of kilowatts are scattered and situated in the field of high voltage lines (66KV and above. These loads are very far from the main feeders/sub-stations (33KV-0.380KV. Feeding such loads in the traditional ways like provision of Diesel-Powered Stations, installation of new distribution lines from the Feeding Centers, or building new Sub-Stations are not practical ways from the economical point of view, because it requires huge additional expenses and will increase electrical power losses. These expenses are not worthy for such loads and therefore, it is necessary to search for other methods to supply them. One of these methods is to use the lightning arrester line as capacitive divider to supply the light loads. In this research, the induced voltage of the lightning arrester line was calculated when it is isolated from the earth. We found the capacitance between lightning arrester line versus the phases and lightning arrester. It was also found the selective power out of the lightning arrester line and the required length which is to be isolated from the earth keeping the main function of the lightning arrester line. When economically comparing between supplying the light electrical loads by traditional ways and the method of lightning arrester, it was found the advantage of using lightning arresters to supply such loads. Also, by using the traditional methods, it was noted that there is a power loss in the power transmission lines by a percentage of 1.8%.

  19. Al-Qaeda arrest casts shadow over the LHC

    CERN Multimedia

    Dacey, James

    2010-01-01

    "Cern remains on course for the imminent switch-on of the Large Hadron Collider (LHC) despite the media frenzy following the recent arrest of a physicist who had been working at the facility. The researcher in question is a 32-year-old man of Algerian descent who is expected to face trail in France - the country in which he was arrested" (0.5 page)

  20. Endodontic Treatment of an Anomalous Anterior Tooth with the Aid of a 3-dimensional Printed Physical Tooth Model.

    Science.gov (United States)

    Byun, Chanhee; Kim, Changhwan; Cho, Seungryong; Baek, Seung Hoon; Kim, Gyutae; Kim, Sahng G; Kim, Sun-Young

    2015-06-01

    Endodontic treatment of tooth formation anomalies is a challenge to clinicians and as such requires a complete understanding of the aberrant root canal anatomy followed by careful root canal disinfection and obturation. Here, we report the use of a 3-dimensional (3D) printed physical tooth model including internal root canal structures for the endodontic treatment of a challenging tooth anomaly. A 12-year-old boy was referred for endodontic treatment of tooth #8. The tooth showed class II mobility with swelling and a sinus tract in the buccal mucosa and periapical radiolucency. The tooth presented a very narrow structure between the crown and root by distal concavity and a severely dilacerated root. Moreover, a perforation site with bleeding and another ditching site were identified around the cervical area in the access cavity. A translucent physical tooth model carrying the information on internal root canal structures was built through a 3-step process: data acquisition by cone-beam computed tomographic scanning, virtual modeling by image processing, and manufacturing by 3D printing. A custom-made guide jig was then fabricated to achieve a safe and precise working path to the root canal. Endodontic procedures including access cavity preparation were performed using the physical tooth model and the guide jig. At the 7-month follow-up, the endodontically treated tooth showed complete periapical healing with no clinical signs and symptoms. This case report describes a novel method of endodontic treatment of an anomalous maxillary central incisor with the aid of a physical tooth model and a custom-made guide jig via 3D printing technique.

  1. Unusual intraosseous transmigration of impacted tooth

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Santosh; Urala, Arun Srinivas; Kamath, Abhay Taranath; Jayaswal, Priyanka; Valiathan, Ashima [Manipal College of Dental Sciences, Manipal (India)

    2012-03-15

    Transmigration of an impacted tooth through the symphyseal suture is a rare and special developmental anomaly of unknown etiology that is unique to the mandibular canine. Maxillary canine transmigration is even rarer. Transmigrated canines are particularly significant due to the aesthetic and functional importance. A maxillary lateral incisor crossing the mid-palatal suture has never been reported in the literature. The aim of this report is to present the first case of simultaneous transmigration of a lateral incisor and canine in the maxilla. The paper also reports four unusual cases of unilateral canine transmigration in the maxilla and mandible and successful eruption of one of the transmigrated mandibular canines following orthodontic traction. Etiology of transmigration and its clinical considerations are also discussed.

  2. Tooth mobility changes subsequent to root fractures

    DEFF Research Database (Denmark)

    Andreasen, Jens Ove; Christensen, Søren Steno Ahrensburg; Tsilingaridis, Georgios

    2012-01-01

    of pulp necrosis in the coronal fragment. Furthermore, the effect of age, location of the fracture on the root, and observation period on mobility values was analyzed. Mobility values were measured for 44 of 95 previous reported root-fractured permanent incisors. Mobility changes were measured......The purpose of this study was to analyze tooth mobility changes in root-fractured permanent teeth and relate this to type of interfragment healing (hard tissue healing (HT), interfragment healing with periodontal ligament (PDL) and nonhealing with interposition of granulation tissue (GT) because...... after 3 months and 1 year, and a normalization of mobility value was usually found after 5 and 10 years. In 17 cases of PDL healing, generally a higher mobility was found in comparison with root fractures healing with hard tissue, and a consistent decrease in mobility value was found in the course...

  3. Restoring gingival harmony around single tooth implants.

    Science.gov (United States)

    Reikie, D F

    1995-07-01

    One of the biggest challenges to restoring a single tooth implant in the esthetic zone of the mouth is the creation of harmonious gingival contour around the restoration. Soft- or hard-tissue deficiencies of the edentulous space are the most common obstacles to achieving gingival symmetry around the proposed restoration. Numerous gingival and osseous grafting and regeneration techniques are available but may complicate treatment by increasing the number of surgical procedures and sites necessary. This article describes a technique for treating mild-to-moderate ridge defects without the required additional surgical procedures or a surgical donor site. Soft-tissue overcontouring is provided around the healing abutment by modification of the surgical flap at second-stage implant surgery. Subsequent gingivoplasty allows establishment of anatomic gingival architecture that surrounds the single implant prosthesis.

  4. Respiratory Arrest in an Obese Pregnant Woman with Hyperemesis Gravidarum

    Directory of Open Access Journals (Sweden)

    Ayumi Iwashita

    2015-01-01

    Full Text Available A pregnant, non-Japanese-speaking Peruvian, and, thus, with communication difficulty, suffered hyperemesis gravidarum and had respiratory arrest, requiring cardiopulmonary resuscitation. The obese pregnant woman (prepregnancy weight: 107 kg had vomited and lost 15 kg in bodyweight over appropriately 2 weeks prior to the arrest but had not complained due to communication difficulty, which, together with her obesity, prevented a Japanese obstetrician from noticing her severe condition. 1,000 mL of low potassium fluid plus thiamine was administered. She became unable to stand, suggesting lower-extremity-proximal-muscle weakness, and then respiratory arrest occurred. Hypopotassemia (2.3 mEq/L, pulseless electrical activity, and muscle weakness suggested the presence of severe potassium deficiency, which may have caused respiratory muscle paralysis, leading to the respiratory arrest. Hypercapnea was severer than expected for compensatory hypoventilation, indicating the presence of concomitant severe hypoventilation, which may also have contributed to respiratory arrest. She recovered with electrolyte and volume replacement. Respiratory arrest can occur with hyperemesis gravidarum, and obesity and communication difficulties can prevent the early detection of severe conditions.

  5. Cardiac arrest due to lymphocytic colitis: a case report

    Directory of Open Access Journals (Sweden)

    Groth Kristian A

    2012-03-01

    Full Text Available Abstract Introduction We present a case of cardiac arrest due to hypokalemia caused by lymphocytic colitis. Case presentation A 69-year-old Caucasian man presented four months prior to a cardiac arrest with watery diarrhea and was diagnosed with lymphocytic colitis. Our patient experienced a witnessed cardiac arrest at his general practitioner's surgery. Two physicians and the emergency medical services resuscitated our patient for one hour and four minutes before arriving at our university hospital. Our patient was defibrillated 16 times due to the recurrence of ventricular tachyarrhythmias. An arterial blood sample revealed a potassium level of 2.0 mmol/L (reference range: 3.5 to 4.6 mmol/L and pH 6.86 (reference range: pH 7.37 to 7.45. As the potassium level was corrected, the propensity for ventricular tachyarrhythmias ceased. Our patient recovered from his cardiac arrest without any neurological deficit. Further tests and examinations revealed no other reason for the cardiac arrest. Conclusion Diarrhea can cause life-threatening situations due to the excretion of potassium, ultimately causing cardiac arrest due to hypokalemia. Physicians treating patients with severe diarrhea should consider monitoring their electrolyte levels.

  6. Associates of Cardiopulmonary Arrest in the Perihemodialytic Period

    Directory of Open Access Journals (Sweden)

    Jennifer E. Flythe

    2014-01-01

    Full Text Available Cardiopulmonary arrest during and proximate to hemodialysis is rare but highly fatal. Studies have examined peridialytic sudden cardiac event risk factors, but no study has considered associates of cardiopulmonary arrests (fatal and nonfatal events including cardiac and respiratory causes. This study was designed to elucidate patient and procedural factors associated with peridialytic cardiopulmonary arrest. Data for this case-control study were taken from the hemodialysis population at Fresenius Medical Care, North America. 924 in-center cardiopulmonary events (cases and 75,538 controls were identified. Cases and controls were 1 : 5 matched on age, sex, race, and diabetes. Predictors of cardiopulmonary arrest were considered for logistic model inclusion. Missed treatments due to hospitalization, lower body mass, coronary artery disease, heart failure, lower albumin and hemoglobin, lower dialysate potassium, higher serum calcium, greater erythropoietin stimulating agent dose, and normalized protein catabolic rate (J-shaped were associated with peridialytic cardiopulmonary arrest. Of these, lower albumin, hemoglobin, and body mass index; higher erythropoietin stimulating agent dose; and greater missed sessions had the strongest associations with outcome. Patient health markers and procedural factors are associated with peridialytic cardiopulmonary arrest. In addition to optimizing nutritional status, it may be prudent to limit exposure to low dialysate potassium (<2 K bath and to use the lowest effective erythropoietin stimulating agent dose.

  7. Exploration of the arrest peptide sequence space reveals arrest-enhanced variants.

    Science.gov (United States)

    Cymer, Florian; Hedman, Rickard; Ismail, Nurzian; von Heijne, Gunnar

    2015-04-17

    Translational arrest peptides (APs) are short stretches of polypeptides that induce translational stalling when synthesized on a ribosome. Mechanical pulling forces acting on the nascent chain can weaken or even abolish stalling. APs can therefore be used as in vivo force sensors, making it possible to measure the forces that act on a nascent chain during translation with single-residue resolution. It is also possible to score the relative strengths of APs by subjecting them to a given pulling force and ranking them according to stalling efficiency. Using the latter approach, we now report an extensive mutagenesis scan of a strong mutant variant of the Mannheimia succiniciproducens SecM AP and identify mutations that further increase the stalling efficiency. Combining three such mutations, we designed an AP that withstands the strongest pulling force we are able to generate at present. We further show that diproline stretches in a nascent protein act as very strong APs when translation is carried out in the absence of elongation factor P. Our findings highlight critical residues in APs, show that certain amino acid sequences induce very strong translational arrest and provide a toolbox of APs of varying strengths that can be used for in vivo force measurements.

  8. Visualization analysis of research frontiers and trends in nerve regeneration and osseoperception in the repair of tooth loss

    Institute of Scientific and Technical Information of China (English)

    Xiaoge Zhang; Tian Tang; Zhihe Zhao; Leilei Zheng; Yin Ding

    2014-01-01

    This study analyzed 85 articles indexed by the Web of Science concerning nerve regeneration and osseoperception during tooth loss repair. Using the Web of Science database and Citespace III software, a document co-citation network map was drawn by document co-citation analysis and word frequency analysis methods. Combined with emergent node secondary literature retrieval, subject headings with apparent changing word frequency trends were retrieved so as to identify research frontiers and development trends. Research frontiers and hotspots for neuronal calcium sensor protein were quantitatively explored to forecast future research developments in nerve regeneration and osseoperception during repair of tooth loss.

  9. Visualization analysis of research frontiers and trends in nerve regeneration and osseoperception in the repair of tooth loss.

    Science.gov (United States)

    Zhang, Xiaoge; Tang, Tian; Zhao, Zhihe; Zheng, Leilei; Ding, Yin

    2014-11-15

    This study analyzed 85 articles indexed by the Web of Science concerning nerve regeneration and osseoperception during tooth loss repair. Using the Web of Science database and Citespace III software, a document co-citation network map was drawn by document co-citation analysis and word frequency analysis methods. Combined with emergent node secondary literature retrieval, subject headings with apparent changing word frequency trends were retrieved so as to identify research frontiers and development trends. Research frontiers and hotspots for neuronal calcium sensor protein were quantitatively explored to forecast future research developments in nerve regeneration and osseoperception during repair of tooth loss.

  10. MICROWAVE PROPAGATION IN TOOTH AND DENTAL DEFECT

    Directory of Open Access Journals (Sweden)

    Maria Papezova

    2016-09-01

    Full Text Available INTRODUCTION:The most common method of conventional dental diagnosisinvolves X-rays, such as Radio Tomography (RT or Computer Tomography (CT. Such methods are used for diagnosing pores in dental material that can lead to premature failure of dental material. Diagnosis by X-ray provides an objective analysis. However, repeated radiation from X-rays can cause biological damage to human tissues. From this point of view, there is a significant need to progress to quantitative non-invasive and non-destructive testing (NDT methods to measure dental material and improve treatment options. This article focuses on applying microwave technology to characterize teeth and teeth replacements. Knowledge of microwave propagation in biomaterial with no defects, using a defined microwave frequency range, and subsequently comparing the result with defective material could provide a means of dental diagnosis without the risk of radiation for the patient, i.e. without X-ray. OBJECTIVES: The primary objective of this study was to examine microwave technology in the field of dental medical diagnosis as a new NDT method. METHODS: The basic concept of applying microwave technology to characterize teeth in dental diagnosis was examined using a basic algorithm designed in the MATLAB programming language. Tests used dielectric properties of tooth and tooth decay and propagated electromagnetic (EM waves to show different characteristics of chosen materials.RESULTS: The analyses of frequency dependent reflection and transmission coefficients of the chosen material, specificallyteeth, atfrequency range 0 GHz to 30 GHz, computed differences between healthy and defective dental material.CONCLUSION: Thus, this could be used in providing a dental diagnosis without exposing patients to radiation, i.e. without X-ray. The next stage will involve creating a complete model of a jaw with teeth, and designing a sensor for crack detection for comparisons using this basic algorithm.

  11. Cardiac arrest during treatment of Pneumocystis carinii pneumonia with intravenous pentamidine isethionate

    DEFF Research Database (Denmark)

    Balslev, U; Berild, D; Nielsen, T L

    1992-01-01

    A 27-year-old man, HIV-positive for 4 years, developed ventricular fibrillation and cardiac arrest during treatment of Pneumocystis carinii pneumonia with intravenous pentamidine isethionate. The dosage was 4 mg/kg/day for 18 days. Nephrotoxicity occurred and raised serum potassium. The plasma...... concentration of pentamidine was 580 nmol/l. Careful monitoring of renal and cardiac functions is recommended during intravenous therapy with pentamidine isethionate....

  12. TOOTH BRUSH - TOOTH PASTE OCULAR INJURY: A SEQUELAE TO FAST LIFE

    Directory of Open Access Journals (Sweden)

    Anil Kumar

    2015-01-01

    Full Text Available Toothbrush - tooth paste, widely used in every house hold, may cause irreversible injury to the eye especially cornea that comes into contact with this substance. We present two cases of toothbrush - toothpaste injury who accidentally injured their own eye. T hese were combination of chemical ( T oothpaste and trivial mechanical ( T oothbrush trauma. Ocular contact with toothpaste causes severe unbearable burning sensation. One of the cases developed suppurative corneal ulcer with hypopyon and lost vision in the affected eye. Toothpastes with more ph can cause blindness when it comes into contact with the eye if not treated urgently. The other patient ( O ne of the consultants in our institute reported immediately in the morning in emergency with complaints of seve re burning sensation in the involved eye after accidental injury with toothbrush - toothpaste. His eyes were washed with normal saline for 30 to 40 minutes. Because he was treated immediately, he recovered within one week. Clinicians should take adequate pre cautions to prevent serious complication. In case of an accidental contact of eye with toothpaste, it is important to wash the eye efficiently. We decided to estimate the ph of commonly used various brands of toothpaste in over biochemistry lab and it was found that ph of various toothpaste varies from 7 to 10. The pH of the brand of the toothpaste which was used by one of the case was (pH 9.6, which shows that it is a combination of mechanical and alkali injury. pH near to neutral (7.1 and 7.4 was detect ed in one of the herbal toothpaste and one the oldest brand of toothpaste ( W hich was not herbal. These cases are being reported to make aware the ophthalmologists and public that although rare but these cases should not be taken lightly and should be trea ted urgently to prevent the loss of vision in the involved eye. One of the risk factors, may be the hurried activities in the morning in this era of fast life a s one of the

  13. Digital modeling technology for full dental crown tooth preparation.

    Science.gov (United States)

    Dai, Ning; Zhong, Yicheng; Liu, Hao; Yuan, Fusong; Sun, Yuchun

    2016-04-01

    A dental defect is one of the most common oral diseases, and it often requires a full crown restoration. In this clinical operation, the dentist must manually prepare the affected tooth for the full crown so that it has a convergence angle between 4° and 10°, no undercuts, and uniform and even shoulder widths and depths using a high speed diamond bur in the patient׳s mouth within one hour, which is a difficult task that requires visual-manual operation. The quality of the tooth preparation has an important effect on the success rate of the subsequent prosthodontic treatment. This study involved research into digital modeling technology for full dental crown tooth preparation. First, the margin line of the tooth preparation was designed using a semi-automatic interactive process. Second, the inserting direction was automatically computed. Then, the characteristic parameters and the constraints on the tooth preparation were defined for the model. Next, the shoulder and axial surface of the tooth preparation were formed using parametric modeling. Finally, the implicit surface of a radial basis function was used to construct the tooth preparation׳s occlusal surface. The experimental results verified that the method of digital modeling for full crown preparation proposed in this study can quickly and accurately implement personalized designs of various parameters, such as the shoulder width and the convergence angle; it provides a digital design tool for full crown preparation.

  14. Safety issues of tooth whitening using peroxide-based materials.

    Science.gov (United States)

    Li, Y; Greenwall, L

    2013-07-01

    In-office tooth whitening using hydrogen peroxide (H₂O₂) has been practised in dentistry without significant safety concerns for more than a century. While few disputes exist regarding the efficacy of peroxide-based at-home whitening since its first introduction in 1989, its safety has been the cause of controversy and concern. This article reviews and discusses safety issues of tooth whitening using peroxide-based materials, including biological properties and toxicology of H₂O₂, use of chlorine dioxide, safety studies on tooth whitening, and clinical considerations of its use. Data accumulated during the last two decades demonstrate that, when used properly, peroxide-based tooth whitening is safe and effective. The most commonly seen side effects are tooth sensitivity and gingival irritation, which are usually mild to moderate and transient. So far there is no evidence of significant health risks associated with tooth whitening; however, potential adverse effects can occur with inappropriate application, abuse, or the use of inappropriate whitening products. With the knowledge on peroxide-based whitening materials and the recognition of potential adverse effects associated with the procedure, dental professionals are able to formulate an effective and safe tooth whitening regimen for individual patients to achieve maximal benefits while minimising potential risks.

  15. Bidirectional communication between oocytes and ovarian follicular somatic cells is required for meiotic arrest of mammalian oocytes

    Science.gov (United States)

    Wigglesworth, Karen; Lee, Kyung-Bon; O’Brien, Marilyn J.; Peng, Jia; Matzuk, Martin M.; Eppig, John J.

    2013-01-01

    Coordinated regulation of oocyte and ovarian follicular development is essential for fertility. In particular, the progression of meiosis, a germ cell-specific cell division that reduces the number of chromosomes from diploid to haploid, must be arrested until just before ovulation. Follicular somatic cells are well-known to impose this arrest, which is essential for oocyte–follicle developmental synchrony. Follicular somatic cells sustain meiotic arrest via the natriuretic peptide C/natriuretic peptide receptor 2 (NPPC/NPR2) system, and possibly also via high levels of the purine hypoxanthine in the follicular fluid. Upon activation by the ligand NPPC, NPR2, the predominant guanylyl cyclase in follicular somatic cells, produces cyclic guanosine monophosphate (cGMP), which maintains meiotic arrest after transfer to the oocyte via gap junctions. Here we report that both the NPPC/NPR2 system and hypoxanthine require the activity of inosine monophosphate dehydrogenase (IMPDH), the rate-limiting enzyme required for the production of guanylyl metabolites and cGMP. Furthermore, oocyte-derived paracrine factors, particularly the growth differentiation factor 9–bone morphogenetic protein 15 heterodimer, promote expression of Impdh and Npr2 and elevate cGMP levels in cumulus cells. Thus, although the somatic compartment of ovarian follicles plays an essential role in the maintenance of oocyte meiotic arrest, as has been known for many years, this function of the somatic cells is surprisingly regulated by signals from the oocyte itself. PMID:23980176

  16. Revitalization of traumatized immature tooth with platelet-rich fibrin

    Directory of Open Access Journals (Sweden)

    Umrana Faizuddin

    2015-01-01

    Full Text Available Endodontic treatment options for immature, nonvital teeth conventionally include surgical endodontics, apexification with calcium hydroxide, or single visit mineral trioxide aggregate plug. Regeneration is a new concept which is been introduced in the treatment of traumatized open apex tooth. Regeneration of pulp-dentin complex in an infected necrotic tooth with an open apex is possible if the canal is effectively disinfected. The purpose of this case report is to add a new vista in regenerative, endodontic therapy by using platelet-rich fibrin for revitalization of immature nonvital tooth.

  17. The role of out-of-hospital cardiac arrest in predicting hospital mortality for percutaneous coronary interventions in the Clinical Outcomes Assessment Program.

    Science.gov (United States)

    Maynard, Charles; Rao, Sunil V; Gregg, Mary; Phillips, Richard C; Reisman, Mark; Tucker, Eben; Goss, J Richard

    2009-01-01

    Published mortality models for percutaneous coronary intervention (PCI), including the Clinical Outcomes Assessment Program (COAP) model, have not considered the effect of out-ofhospital cardiac arrest. The primary objective of this study was to determine if the inclusion of out-of-hospital cardiac arrest altered the COAP mortality model for PCI. The COAP PCI database contains extensive demographic, clinical, procedural and outcome information, including out-of-hospital cardiac arrest, which was added to the data collection form in 2006. This study included 15,586 consecutive PCIs performed in 31 Washington State hospitals in 2006. Using development and test sets, the existing COAP PCI logistic regression mortality model was examined to assess the effect of out-of-hospital arrest on in-hospital mortality. Overall, 2% of individuals undergoing PCI had cardiac arrest prior to hospital arrival. Among 8 hospitals with PCI volumes 120 cases per year did. In-hospital mortality was 19% in the arrest group and was 1.0% in remaining procedures (p < 0.0001). In the new multivariate model, out-of-hospital cardiac arrest was highly associated with mortality (odds ratio = 5.50; 95% confidence interval [CI] = 3.28-9.25). When evaluated in the test set, the new model had excellent discrimination (c-statistic = 0.89; 95% CI = 0.85-0.93). Out-of-hospital cardiac arrest is an important determinant of risk-adjusted in-hospital mortality for PCI, particularly for hospitals with low volumes and relatively high volumes of cardiac arrest cases.

  18. Effects of tooth profile modification on dynamic responses of a high speed gear-rotor-bearing system

    Science.gov (United States)

    Hu, Zehua; Tang, Jinyuan; Zhong, Jue; Chen, Siyu; Yan, Haiyan

    2016-08-01

    A finite element node dynamic model of a high speed gear-rotor-bearing system considering the time-varying mesh stiffness, backlash, gyroscopic effect and transmission error excitation is developed. Different tooth profile modifications are introduced into the gear pair and corresponding time-varying mesh stiffness curves are obtained. Effects of the tooth profile modification on mesh stiffness are analyzed, and the natural frequencies and mode shapes of the gear-rotor-bearing transmission system are given. The dynamic responses with respect to a wide input speed region including dynamic factor, vibration amplitude near the bearing and dynamic transmission error are obtained by introducing the time-varying mesh stiffness in different tooth profile modification cases into the gear-rotor-bearing dynamic system. Effects of the tooth profile modification on the dynamic responses are studied in detail. The numerical simulation results show that both the short profile modification and the long profile modification can affect the mutation of the mesh stiffness when the number of engaging tooth pairs changes. A short profile modification with an appropriate modification amount can improve the dynamic property of the system in certain work condition.

  19. Estimation of gear tooth transverse crack size from vibration by fusing selected gear condition indices

    Science.gov (United States)

    Choi, Sukhwan; Li, C. James

    2006-09-01

    Gears are common power transmission elements and are frequently responsible for transmission failures. Since a tooth crack is not directly measurable while a gear is in operation, one has to develop an indirect method to estimate its size from some measurables. This study developed such a method to estimate the size of a tooth transverse crack for a spur gear in operation. Using gear vibrations measured from an actual gear accelerated test, this study examined existing gear condition indices to identify those correlated well to crack size and established their utility for crack size estimation through index fusion using a neural network. When tested with vibrations measured from another accelerated test, the method had an averaged estimation error of about 5%.

  20. 3-D analysis of tooth formation and eruption in patients with craniofacial anomalies

    DEFF Research Database (Denmark)

    Kreiborg, Sven; Larsen, Per; Bro-Nielsen, Morten

    1996-01-01

    A number of craniofacial anomalies or syndromes involve severe disturbances of tooth formation and eruption (e.g. Apert syndrome, Crouzon syndrome, tricho-dento-osseous syndrome, cleidocranial dysplasia, and cleft lip and palate). So far, studies of these dental problems have been limited to two......-dimensional analysis from orthopantomograms, intra-oral X-rays or cephalometric radiographs. A method for visualization of the developing tooth crowns in three dimensions based on CT-scans of the jaws has been developed (Bro-Nielsen et al., 1996). The purpose of the present study was to apply this new visualization...... method to the analysis of the complex dental problems found in some of the syndromes listed above....