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Sample records for hiperestesia dentinal causas

  1. Retracción gingival e hiperestesia dentinal: Causas y prevención Gingival recession and dentine hypersensitivity

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    Jorge Sotres Vázquez

    2004-08-01

    Full Text Available Se realizó una investigación en 230 pacientes que acudieron a los Servicios de Prótesis y Periodoncia de la Clínica Estomatológica "Hermanos Gómez" durante el año 2002. Se les evaluó la presencia de retracción gingival, sus causas y la relación existente con la hiperestesia dentinal. Se determinó que el 17,3 % de los dientes examinados presentaron algún grado de retracción gingival. Las causas más frecuentes fueron ausencia de dientes antagonistas e inserciones frénicas anormales. Existió una estrecha relación entre la hiperestesia dentinal y la retracción gingival. No existieron diferencias significativas de retracción gingival según el sexo, pero sí con la edad, pues aumentó significativamente según aumentó la edad.A research study was performed on 230 patients who went to the Denture and Periodontics Service at "Hermanos Gómez" dental clinic in the year 2002. They were evaluated as to presence of gingival recession, its causes and its relation with dentine hypersensitity. It was determined that 17,3% of examined teeth presented with some level of gingival recession frequently caused by lack of opposite teeth and abnormal frenal insertions. Gingival recession did not show significant differences by sex but it did by age since it markedly increased with the age.

  2. Clinical evaluation of dentin hypersensitivity treatment with the low intensity Gallium-Aluminum-Arsenide laser - AsGaAl Avaliação clínica do tratamento da hiperestesia dentinária com laser de baixa potência de Arseniato de Gálio-Alumínio - AsGaAl

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    Luciana Chucre Gentile

    2004-12-01

    Full Text Available The dentin hypersensitivity is a painful condition rather prevalent in the general population. There are several ways of treatment for such condition, including the low intensity lasers. The proposal of this study was to verify the effectiveness of the Gallium-Aluminum-Arsenide diode laser in the treatment of this painful condition, using a placebo as control. MATERIALS AND METHODS: Thirty-two patients were selected, 22 females and 10 males, with ages ranging from 20 to 52 years old. The 32 patients were randomly distributed into two groups, treated and control; the sample consisted of 68 teeth, 35 in the treated group and 33 in the control group. The treated group was exposed to six laser applications with intervals from 48 to 72 hours, and the control group received, as placebo, applications of a curing light. RESULTS: A significant reduction was observed in the pain condition between the initial phase and after six laser applications; however, such reduction could also be observed for the control group exposed to the placebo. CONCLUSION: Therapy with the low intensity Gallium-Aluminum-Arsenide laser - AsGaAl induces a statistically significant reduction in the painful condition after each application and between the beginning and end of treatment, although there was no statistically significant difference between the treated group (laser and the control group (placebo at the end of treatment and after the mediate evaluation results (after 6 weeks, this way impairing the real measurement of laser effectiveness and placebo effect.A hiperestesia dentinária trata-se de uma condição dolorosa bastante prevalente nas populações mundiais. Várias são as modalidades de tratamento para tal condição, entre elas, os lasers de baixa potência. A proposta deste estudo foi a de verificar a efetividade do laser de diodo de Arseniato de Gálio-Alumínio no tratamento desta condição dolorosa, utilizando-se um placebo como controle. MATERIAIS E M

  3. Dentin Sialophophoprotein (DSPP) and Dentin

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    Yamakoshi, Yasuo

    2008-01-01

    The revolution in genetics disclosed the types of malformations that occur when expression of a particular gene is lost. In the case of tooth dentin, mutations in the two genes encoding type I collagen cause osteogenesis imperfecta, a bone condition that often includes dentin malformations. Besides collagen, there are a number of non-collagenous proteins in dentin. Among the genes encoding the dentin non-collagenous proteins, only mutations in DSPP (dentin sialophosphoprotein) cause inherited...

  4. Mercadeando causas ambientales

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    Diana Forero

    2013-06-01

    Full Text Available En el presente escrito se presentan varias alternativas para el desarrollo del mercadeo de causas ambientales a través de entidades sin ánimo de lucro. En la primera parte se exploran los modelos de mercadeo que se han empelado con mayor regula-ridad: la filantropía estratégica, el mercadeo social y el mercadeo de causas. Se muestran las actividades más comunes en cada tipo de mercadeo y algunos puntos clave para desarrollarlo. En la segunda parte se presentan las barreras para la gestión del mercadeo de causas ambientales, señalando en qué consisten esas barreras, los puntos críticos y algunas alternativas planteadas desde la comunicación organizacional, la negociación, la gestión de relaciones con clientes y el control de gestión.

  5. Robert Paine Doctor Honoris Causa

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    Per Mathiesen

    1998-02-01

    Full Text Available Professor Emeritus Dr. Robert Paine was conferred the degree of Doctor Honoris Causa at the University of Tromsø on August 27 1998 as a recognition of his long lasting and continuing influence on the anthropological study of modern society, and in particular his many contributions to the understanding of Sami reindeer husbandry and the Sami culture in general.

  6. Disorders of Human Dentin

    OpenAIRE

    Hart, P Suzanne; Hart, Thomas C.

    2007-01-01

    Dentin, the most abundant tissue in teeth, is produced by odontoblasts, which differentiate from mesenchymal cells of the dental papilla. Dentinogenesis is a highly controlled process that results in the conversion of unmineralized predentin to mineralized dentin. By weight, 70% of the dentin matrix is mineralized, while the organic phase accounts for 20% and water constitutes the remaining 10%. Type I collagen is the primary component (>85%) of the organic portion of dentin. The non-collagen...

  7. Mercadotecnia social y de causas.

    OpenAIRE

    Julie A. Garrett; Lisa S Rochlin; Gloria Coe

    2015-01-01

    A partir de 1960 el público estadounidense empezó a presionar a la comunidad empresarial para que manifestará su responsabilidad social. Para los años ochenta, las empresas consideraron nuevos modelos de filantropía, American Express, acuñó la frase de "mercadotecnia de causas" para describir las relaciones beneficiosas entre las empresas y las entidades sin fines de lucro. México ha sido un ejemplo al aceptar la participación empresarial en cuestiones comunitarias y sociales gracias a los es...

  8. Mercadotecnia social y de causas.

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    Julie A. Garrett

    2015-01-01

    Full Text Available A partir de 1960 el público estadounidense empezó a presionar a la comunidad empresarial para que manifestará su responsabilidad social. Para los años ochenta, las empresas consideraron nuevos modelos de filantropía, American Express, acuñó la frase de "mercadotecnia de causas" para describir las relaciones beneficiosas entre las empresas y las entidades sin fines de lucro. México ha sido un ejemplo al aceptar la participación empresarial en cuestiones comunitarias y sociales gracias a los esfuerzos de la Organización Panamericana de la Salud.

  9. Biomimetic remineralization of dentin.

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    Niu, Li-Na; Zhang, Wei; Pashley, David H; Breschi, Lorenzo; Mao, Jing; Chen, Ji-Hua; Tay, Franklin R

    2014-01-01

    Remineralization of demineralized dentin is important for improving dentin bonding stability and controlling primary and secondary caries. Nevertheless, conventional dentin remineralization strategy is not suitable for remineralizing completely demineralized dentin within hybrid layers created by etch-and-rinse and moderately aggressive self-etch adhesive systems, or the superficial part of a caries-affected dentin lesion left behind after minimally invasive caries removal. Biomimetic remineralization represents a different approach to this problem by attempting to backfill the demineralized dentin collagen with liquid-like amorphous calcium phosphate nanoprecursor particles that are stabilized by biomimetic analogs of noncollagenous proteins. This paper reviewed the changing concepts in calcium phosphate mineralization of fibrillar collagen, including the recently discovered, non-classical particle-based crystallization concept, formation of polymer-induced liquid-precursors (PILP), experimental collagen models for mineralization, and the need for using phosphate-containing biomimetic analogs for biomimetic mineralization of collagen. Published work on the remineralization of resin-dentin bonds and artificial caries-like lesions by various research groups was then reviewed. Finally, the problems and progress associated with the translation of a scientifically sound concept into a clinically applicable approach are discussed. The particle-based biomimetic remineralization strategy based on the PILP process demonstrates great potential in remineralizing faulty hybrid layers or caries-like dentin. Based on this concept, research in the development of more clinically feasible dentin remineralization strategy, such as incorporating poly(anionic) acid-stabilized amorphous calcium phosphate nanoprecursor-containing mesoporous silica nanofillers in dentin adhesives, may provide a promising strategy for increasing of the durability of resin-dentin bonding and

  10. Dentin hypersensitive: Ethiology and treatment

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    Nuryanni Dihin Utami

    2017-08-01

    Full Text Available Dentin hypersensitivity is a response in exposed dentine with a symptom of clinically sharp and short pain. This condition may occur to exposed dentine due to gingival recession or enamel loss. Dentin hypersensitivity treatment aimed to either occlude the open dentinal tubules or block the neural response of the pulp. Invasive treatment are pulpectomy, restoration or surgery, while non invasive treatment are usually done by using tooth paste or mouthwash which is added by desensitizing agent

  11. Epidemiology of dentin hypersensitivity

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    Splieth, Christian H.; Tachou, Aikaterini

    2012-01-01

    Objective In contrast to the well-established caries epidemiology, data on dentin hypersensitivity seem to be scarce and contradictory. This review evaluates the available literature on dentin hypersensitivity and assesses its prevalence, distribution, and potential changes. Materials and methods The systematic search was performed to identify and select relevant publications with several key words in electronic databases. In addition, the articles? bibliographies were consulted. Results Prev...

  12. Regulation of Reactionary Dentine Formation.

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    Neves, V C M; Sharpe, P T

    2017-11-01

    During the treatment of dental caries that has not penetrated the tooth pulp, maintenance of as much unaffected dentine as possible is a major goal during the physical removal of decayed mineral. Damage to dentine leads to release of fossilized factors (transforming growth factor-β [TGF-β] and bone morphogenic protein [BMP]) in the dentine that are believed to stimulate odontoblasts to secrete new "tertiary" dentine (reactionary dentine). This is formed on the pulpal surface of existing dentine and rethickens the dentine. We have previously shown that activation of Wnt/β-catenin signaling is pivotal for tooth repair in exposed pulp injury, and the pathway can be activated by small-molecule GSK-3 antagonists, resulting in enhanced reparative dentine formation. Here, we use a nonexposed pulp injury model to investigate the mechanisms of reactionary dentine formation in vivo, using small molecules to modulate the Wnt/β-catenin, TGF-β, and BMP pathways. We found that a local increase of Wnt activation at the injury site enhances reactionary dentine secretion. In addition, inhibition of TGF-β, BMP, or Wnt pathways does not impede reactionary dentine formation, although inhibition of TGF-β and/or BMP signaling does result in more disorganized, nontubular reactionary dentine. This suggests that Wnt/β-catenin signaling plays no major role in the formation of reactionary dentine, but in common with reparative dentine formation, exogenous elevation of Wnt/β-catenin signaling can enhance tertiary dentine formation. Release of latent TGF-β or BMPs from dentine is not required for the deposition of mineral to form reactionary dentine but does play a role in its organization.

  13. Dentin: structure, composition and mineralization.

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    Goldberg, Michel; Kulkarni, Askok B; Young, Marian; Boskey, Adele

    2011-01-01

    We review firstly the specificities of the different types of dentin present in mammalian teeth. The outer layers include the mantle dentin, the Tomes' granular and the hyaline Hopewell-Smith's layers. Circumpulpal dentin forming the bulk of the tooth, comprises intertubular and peritubular dentin. In addition to physiological primary and secondary dentin formation, reactionary dentin is produced in response to pathological events. Secondly, we evaluate the role of odontoblasts in dentin formation, their implication in the synthesis and secretion of type I collagen fibrils and non-collagenous molecules. Thirdly, we study the composition and functions of dentin extracellular matrix (ECM) molecules implicated in dentinogenesis. As structural proteins they are mineralization promoters or inhibitors. They are also signaling molecules. Three different forms of dentinogenesis are identified: i) matrix vesicles are implicated in early dentin formation, ii) collagen and some proteoglycans are involved in the formation of predentin, further transformed into intertubular dentin, iii) the distal secretion of some non-collagenous ECM molecules and some serum proteins contribute to the formation of peritubular dentin.

  14. Comportamiento de la sensibilidad dentinal en pacientes del municipio "10 de Octubre" Behavior of dentinal sensitivity in patients from the "10 de Octubre" municipality

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    Nereyda Riesgo Lobaina

    2010-03-01

    Full Text Available Se realizó un estudio descriptivo transversal con el objetivo de determinar el comportamiento de la sensibilidad dentinal en tres clínicas estomatológicas del municipio "10 de Octubre". Las variables estudiadas fueron: edad, sexo, factores predisponentes, grado del dolor, grupos de dientes examinados y tipo de retracción periodontal presente. Se encontraron 150 pacientes que presentaron 190 dientes afectados por sensibilidad dentinal. El sexo femenino fue el más representado, así como los grupos de edades más jóvenes. Se encontró que el grado 3 de dolor prevaleció y estuvo más relacionado con la recesión peridontal tipo III. La causa más frecuente de sensibilidad dentinal fue el cepillado dental.A cross-sectional and descriptive study was conducted to determine the behavior of dentinal sensitivity in patients of three Stomatology Clinics from "10 de Octubre" municipality. Study variable were: age, sex, predisposing factors, pain degree, groups of examined teeth and the type of periodontal retraction present. There were 150 patients with 190 teeth involved by dentinal sensitivity. Female sex was the more affected one, as well as the younger age groups. We found that 3 degree pain prevailed and that it was more related to type III periodontal recession. The more frequent cause of dentinal sensitivity was the dental brushing.

  15. Bonding to caries-affected dentin

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    Masatoshi Nakajima

    2011-08-01

    Full Text Available Dentin adhesive systems have dramatically developed during the past decades. In a prepared cavity for an adhesive composite restoration, large areas of the cavity floor are composed of caries-affected dentin after removal of caries-infected dentin, not normal dentin. Caries-affected dentin is different in morphological, chemical and physical characteristics from normal dentin. Therefore, caries-affected dentin has still problems as bonding substrate compared with normal dentin. That is, caries-affected dentin produces lower bond strength and poor quality of the hybrid layer than normal dentin. In addition, when exposed the adhesive interface of caries-affected dentin in oral environment, the poor quality of the hybrid layer would compromise the longevity of the composite restoration due to hydrolysis of the resin and collagen fibrils. The improvement of bonding potential to caries-affected dentin could lead to reinforcement of tooth-composite restoration complex, protecting secondary caries and tooth fracture.

  16. Resin adhesion to carious dentin.

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    Yoshiyama, Masahiro; Tay, Franklin R; Torii, Yasuhiro; Nishitani, Yoshihiro; Doi, Junichi; Itou, Kousuke; Ciucchi, Bernard; Pashley, David H

    2003-02-01

    To investigate the microtensile bond strength (microTBS) of a self-etching priming adhesive system to normal, caries-affected and caries-infected dentin, and to observe the ultrastructure of the resin-dentin interface by transmission electron microscopy (TEM). Twelve extracted human molar teeth with deep occlusal caries were stained with caries detector solution and ground flat occlusally. The red-stained soft dentin was classified as caries-infected. The surrounding discolored dentin was classified as caries-affected dentin. The surrounding normal dentin served as a control. The entire flat surface was bonded with Clearfil Liner Bond 2V (CV) and covered with resin composite to form a composite crown 5 mm high. One day later the specimens were serially sectioned vertically into multiple slabs 0.8 mm thick. Under microscopic observation, the specimens were divided into normal or caries-infected or caries-affected dentin. These regions were isolated by cutting away the remaining dentin to form hour-glass shapes with the smallest surface area at the test site. After measuring the areas, the specimens were fixed to a microtensile tester and pulled under tension to failure. Additional slabs that were not used for bond strength tests were processed for TEM. Bond strength data were analyzed by Kruskal-Wallis one-way ANOVA and Student-Newman-Keuls multiple comparisons. The microTBS of CV to normal, caries-affected and caries-infected dentin were 45 +/- 10 MPa, 30 +/- 10 MPa, 10 +/- 5 MPa, respectively. TEM images showed that CV formed thin hybrid layers that were less than 1 microm thick in normal dentin, but that were between 6-8 microm thick in caries-affected dentin. Bacteria were only sparsely observed in the dentin tubules of bonded caries-affected dentin. However, in caries-infected dentin, an unusual interface was seen in which carious bacteria within disorganized non-banded collagen fibrils could be seen embedded by the adhesive. The hybrid layer in caries

  17. Comportamiento de la sensibilidad dentinal en pacientes del municipio "10 de Octubre"

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    Nereyda Riesgo Lobaina

    2010-03-01

    Full Text Available Se realizó un estudio descriptivo transversal con el objetivo de determinar el comportamiento de la sensibilidad dentinal en tres clínicas estomatológicas del municipio "10 de Octubre". Las variables estudiadas fueron: edad, sexo, factores predisponentes, grado del dolor, grupos de dientes examinados y tipo de retracción periodontal presente. Se encontraron 150 pacientes que presentaron 190 dientes afectados por sensibilidad dentinal. El sexo femenino fue el más representado, así como los grupos de edades más jóvenes. Se encontró que el grado 3 de dolor prevaleció y estuvo más relacionado con la recesión peridontal tipo III. La causa más frecuente de sensibilidad dentinal fue el cepillado dental.

  18. SCANNING ELECTRON MICROSCOPIC INVESTIGATION OF DENTINAL TUBULES IN MONKEY DENTIN SCANNING ELECTRON MICROSCOPIC INVESTIGATION OF DENTINAL TUBULES IN Cebus apella DENTIN

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    João Humberto Antoniazzi

    2009-12-01

    Full Text Available

    The aim of the study was to investigate the number and diameter of the Cebus apella dentinal tubules. The roots of the Cebus apella teeth were examined in specific tooth locations: the apical, middle and cervical dentin. The calculations were based on the scanning electron microscope photographs of the fractured surfaces. The results showed that the average number of dentinal tubules for each location was: 74,800 tubules/mm2 for apical root dentin, 90,000 tubules/mm2 for mid-root dentin, 91,600 tubules/mm2 for cervical root dentin. The average diameter was the following: apical root dentin, 4,30µm; mid-root dentin, 4,37µm; cervical root dentin,  5,23µm. These findings demonstrate that the Cebus apella teeth are a suitable substitute for human in endodontics studies. 

    KEY WORDS: Dentin, dentinal tubules, teeth.
    The aim of the study was to investigate the number and diameter of the Cebus apella dentinal tubules. The roots of the Cebus apella teeth were examined in specific tooth locations: the apical, middle and cervical dentin. The calculations were based on the scanning electron microscope photographs of the fractured surfaces. The results showed that the average number of dentinal tubules for each location was: 74,800 tubules/mm2 for apical root dentin, 90,000 tubules/mm2 for mid-root dentin, 91,600 tubules/mm2 for cervical root dentin. The average diameter was the following: apical root dentin, 4,30µm; mid-root dentin, 4,37µm; cervical root dentin,  5,23µm. These findings demonstrate that the Cebus apella teeth are a suitable substitute for human in endodontics studies. 

    KEY WORDS: Dentin, dentinal tubules, teeth.

  19. Galactosemia como causa de ictericia neonatal

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    Mery Yolanda Cifuentes-Cifuentes; Antonio Estrada-Vizcaíno; Rosa Romero C

    2014-01-01

    La ictericia es un problema muy frecuente en las unidades de recién nacidos. En este documento se presenta el caso de un neonato que cursó con hiperbilirrubinemia, inicialmente con predominio de la bilirrubina indirecta y posteriormente con anemia, hepatomegalia, aumento de la bilirrubina directa, alteración de la función hepática, disfunción tubular renal, cataratas y lesiones en la sustancia blanca del SNC. Se descartaron diversas causas de hiperbilirrubinemia directa en el neonato. Se enco...

  20. Shear strength of dentin and dentin bonded composites.

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    Mondragon, E; Söderholm, K J

    2001-01-01

    The objective of this study was to compare the shear strength of dentin with the shear strength of dentin bonded composites, and to determine how variables such as composite strength and blade width used during shear testing influence shear strength values. Dentin test samples (n = 36) were made by milling the anatomical molar crowns to a shape similar to a composite rod bonded to a flat dentin surface. Dentin bonding was accomplished by bonding composites to flat dentin surfaces (n = 72) using Scotchbond MP and Z100 (n = 36) or Silux Plus (n = 36) composites. Shear testing was conducted using a guillotine-like device with a flat blade embracing half the dentin or composite cylinders. The blade thickness was either 0.25, 0.5, 0.75, 1.0, 1.25, or 1.50 mm. Six samples per material and blade thickness were tested. In addition to the above study, the bond strength of Z100 (n = 6) and Silux (n = 6) bonded with Scotchbond MP and tested with an orthodontic edgewire loop were also tested and compared with the bond strength of the Z100 and Silux samples tested with the 0.5 thick blade. All shear testing was done at a load rate of 0.5 mm/min. The results were analyzed using ANOVA and Duncan's multiple range test. The shear strength values when tested with the blades were: dentin = 39.7 +/- 13.0 MPa, Z100 = 29.3 +/- 7.2 MPa, and Silux = 21.1 +/- 4.9 MPa; each group had significantly different values (p bonding agent is significantly lower than the shear strength of dentin. The shear strength depends on testing method (blade vs loop) and composite material.

  1. Causa Efficiens versus Causa Formalis: origens da discuss\\~ao moderna sobre a dimensionalidade do espa\\c{c}o

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    Caruso, Francisco

    2015-01-01

    Metascientific criteria used for explaining or constraining physical space dimensionality and their historical relationship to prevailing causal systems are discussed. The important contributions by Aristotle, Kant and Ehrenfest to the dimensionality of space problem are considered and shown to be grounded on different causal explanations: {\\it causa materialis} for Aristotle, {\\it causa efficiens} for young Kant and an ingenious combination of {\\it causa efficiens} and {\\it causa formalis} for Ehrenfest. The prominent and growing r\\^ole played by {\\it causa formalis} in modern physical approaches to this problem is emphasized.

  2. Functional remineralization of carious dentin

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    Pugach, Megan Kardon

    A primary goal of dental tissue engineering is the biological reconstruction of tooth substrate destroyed by caries or other diseases affecting tooth mineralization. Traditionally, dentists treat caries by using invasive techniques to remove the diseased dental tissue and restore the lesion, ideally preventing further progression of decay. Success in strategies associated with remineralization of enamel and root caries have contributed to the less invasive prospect of remineralization of dentinal carious lesions. The central hypothesis of this dissertation is that carious dentin lesions can be remineralized if the lesions contain residual mineral. Caries Detector (CD) stained zones (pink, light pink, transparent and normal) of arrested carious dentin lesions were characterized according to microstructure by atomic force microscopy (AFM) imaging, mineral content by digital transverse microradiography, and nanomechanical properties by AFM-based nanoindentation. CD-stained and unstained zones had significantly different microstructure, mineral content and nanomechanical properties. Furthermore, the most demineralized carious zone contained residual mineral. To obtain reproducible, standardized dentin caries lesions, we characterized the lesions from an artificial carious dentin lesion model using a 0.05M acetate demineralization buffer. The artificial caries-like lesions produced by the buffer had similar mineral content and nanomechanical properties in the stained and unstained zones as natural dentin lesions. Both natural and artificial lesions had significant correlations between mineral content and nanomechanical properties. Mineral crystallite size and shape was examined by small angle x-ray scattering. Both natural and artificial carious dentin had different mineral sizes than normal dentin. Collagen in natural and artificial carious dentin lesions was examined by trichrome stain, AFM high-resolution imaging, and UV resonance Raman spectroscopy, to determine if

  3. Rootless teeth: Dentin dysplasia type I

    National Research Council Canada - National Science Library

    Fulari, Sangamesh G; Tambake, Deepti P

    2013-01-01

    A rare case of hereditary disturbance of dentine, Dentin dysplasia type I is presented, which is characterized by short or total absence of roots, obliterated pulp chambers, and peri-apical radiolucencies...

  4. Galactosemia como causa de ictericia neonatal

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    Mery Yolanda Cifuentes-Cifuentes

    2014-04-01

    Full Text Available La ictericia es un problema muy frecuente en las unidades de recién nacidos. En este documento se presenta el caso de un neonato que cursó con hiperbilirrubinemia, inicialmente con predominio de la bilirrubina indirecta y posteriormente con anemia, hepatomegalia, aumento de la bilirrubina directa, alteración de la función hepática, disfunción tubular renal, cataratas y lesiones en la sustancia blanca del SNC. Se descartaron diversas causas de hiperbilirrubinemia directa en el neonato. Se encontró positiva una prueba de azúcares reductores en orina que resultó ser galactosa en la cromatografía en capa fina. Se documentó marcada reducción de la actividad enzimática de galactosa uridil transferasa, con lo cual se confirmó el diagnóstico de galactosemia. Se suspendió la alimentación con leche materna, se inició leche de soya con resolución del cuadro clínico.

  5. Ultrastructural organization of dentin in mice lacking dentin sialo-phosphoprotein.

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    Fang, Ping-An; Verdelis, Kostas; Yang, Xu; Lukashova, Lyudmila; Boskey, Adele L; Beniash, Elia

    2014-08-01

    Dentin Sialophosphoprotein (DSPP) is the major non-collagenous protein of dentin and plays a significant role in dentin mineralization. Recently, animal models lacking DSPP have been developed and the DSPP KO phenotype has been characterized at the histological level. Little is known, however, about the DSPP KO dentin at nano- and meso-scale. Dentin is a hierarchical material spanning from nano- to macroscale, hence information on the effects of DSPP deficiency at the submicron scale is essential for understanding of its role in dentin biomineralization. To bridge this gap, we have conducted ultrastructural studies of dentin from DSPP KO animals. Transmission electron microscopy (TEM) studies of DSPP KO dentin revealed that although the overall ultrastructural organization was similar to the WT, the mineral particles were less organized. Scanning electron microscopy in the back-scattered mode (BS-SEM) of the DSPP KO dentin revealed that circumpulpal dentin comprises large areas of non-mineralized matrix, with numerous spherulitic mineralized inclusions, while the mantle dentin appeared largely unaffected. Analysis of the mineral distribution in the circumpulpal dentin of the DSPP KO mice suggests a reduction in the number of mineral nucleation sites and an increase in the nucleation barrier in DSPP KO dentin. These preliminary results indicate that in addition to the reduction of mineralized and total dentin volume in DSPP KO animals significant changes in the ultrastructural organization exist. These changes are likely related to the role of DSPP in the regulation of mineral formation and organization in dentin.

  6. Femtosecond laser ablation of dentin

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    Alves, S.; Oliveira, V.; Vilar, R.

    2012-06-01

    The surface morphology, structure and composition of human dentin treated with a femtosecond infrared laser (pulse duration 500 fs, wavelength 1030 nm, fluences ranging from 1 to 3 J cm-2) was studied by scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The average dentin ablation threshold under these conditions was 0.6 ± 0.2 J cm-2 and the ablation rate achieved in the range 1 to 2 µm/pulse for an average fluence of 3 J cm-2. The ablation surfaces present an irregular and rugged appearance, with no significant traces of melting, deformation, cracking or carbonization. The smear layer was entirely removed by the laser treatment. For fluences only slightly higher than the ablation threshold the morphology of the laser-treated surfaces was very similar to the dentin fracture surfaces and the dentinal tubules remained open. For higher fluences, the surface was more porous and the dentin structure was partially concealed by ablation debris and a few resolidified droplets. Independently on the laser processing parameters and laser processing method used no sub-superficial cracking was observed. The dentin constitution and chemical composition was not significantly modified by the laser treatment in the processing parameter range used. In particular, the organic matter is not preferentially removed from the surface and no traces of high temperature phosphates, such as the β-tricalcium phosphate, were observed. The achieved results are compatible with an electrostatic ablation mechanism. In conclusion, the high beam quality and short pulse duration of the ultrafast laser used should allow the accurate preparation of cavities, with negligible damage of the underlying material.

  7. Evaluation of inactivation of intracanal antiseptics by dentin, demineralized dentin, dentin matrix and mineral component of dentin

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    Razmi H

    2007-01-01

    Full Text Available Background and Aim: Many studies have shown that microorganisms are the main cause of pulpal diseases and the main purpose of root canal therapy is their elimination from the root canal system. Antiseptic agents are used to reduce bacteria but their antibacterial activities differ from in vivo to in vitro studies and might be inactivated by dentin and its components in root canal space. This study was designed to investigate the effect of dentin on antibacterial activity of different antimicrobial agents. Materials and Methods: In this experimental study, two antibacterial agents (sodium hypochlorite and chlorhexidine with different concentrations were used in four experimental groups: Group 1: dentin, Group 2: demineralized dentin with EDTA, Group 3: dentin matrix and Group 4: dentin mineral component. The species used in this study was Entrococcus faecalis. Different concentration of agents were added to mixture of each experimental group and bacteria. At the baseline and after one and 24 hours, samples were collected and cultured. After incubation period, colonies were counted. Data were analyzed by Tukey test with p<0.05 as the limit of significance. Results: 2% and 0.2% chlorhexidine, and 5% sodium hypochlorite solutions at the three studied times eliminated Entrococcus faecalis completely. 1% sodium hypochlorite eliminated all bacteria in 1h and 24 hs. Statistical analysis showed significant differences between experimental and control groups (P<0.05. Sodium 1% hypochlorite at time 0, could reduce bacteria significantly (P<0.05 but didn’t eliminate them completely. Conclusion: Inactivation of intracanal antiseptics was not observed in this study. As elimination of bacteria occurred, application of these antibacterial agents are recommended in endodontic treatment. Further investigations on other antibacterial agents, other concentrations and shorter time intervals are recommended.

  8. Lesões por causas externas em clube recreativo

    OpenAIRE

    Caixeta, Adriana

    2005-01-01

    A recreação como atividade física e a prática de esportes têm sido associadas à vida saudável e ao bem estar físico e mental, mas também causa lesões. O objetivo do presente estudo foi o de conhecer a epidemiologia e caracterizar as principais lesões por causas externas que ocorrem em um clube recreativo e esportivo da cidade de Uberlândia (MG). Foram obtidos prospectivamente dados de 885 casos de lesões por causas externas atendidos, em 2004, no departamento médico do clube. A...

  9. Effect of desensitizing toothpastes on dentin

    Directory of Open Access Journals (Sweden)

    Shelon Cristina Souza Pinto

    2012-10-01

    Full Text Available The objective of this study was to analyze the effects of toothbrushing with desensitizing toothpastes on dentin permeability and dentinal tubule occlusion. Fifty rats provided two hundred incisor teeth divided into five groups: DW, brushed with distilled water (control; FT, brushed with fluoride toothpaste; SCT, brushed with strontium chloride toothpaste; PCT, brushed with potassium citrate toothpaste; and PNT, brushed with potassium nitrate toothpaste. Cavities were prepared to expose the dentinal tubules, and the incisor teeth were brushed using the experimental agents. After each treatment, Evans blue dye solution was applied to the teeth. Dentin permeability was analyzed using scanning electron microscopy and energy-dispersive X-rays (EDX. There were significant differences (p < 0.0001, ANOVA among the groups regarding dentin permeability, number of dentinal tubules, diameter of dentinal tubules, and opened tubular area. In the SCT, PCT and PNT groups, opened and partially occluded tubules, deposits, and a few smear layers were observed. In the DW and FT groups, most of the dentinal tubules were open, with no deposits or smear layers on the dentin. EDX revealed peaks of calcium and phosphorus in all of the groups, as well as traces of strontium in the SCT group and of potassium in the PCT and PNT groups. Desensitizing toothpaste decreased dentin permeability, although it produced only partial dentin tubule occlusion.

  10. Adhesion to bovine dentin: Surface characterization

    Energy Technology Data Exchange (ETDEWEB)

    Ruse, N.D.; Smith, D.C. (Centre for Biomaterials, Faculty of Dentistry, University of Toronto, Ontario (Canada))

    1991-06-01

    x-ray photo-electron spectroscopy (xPS) and secondary ion mass spectrometry (SIMS) were used to characterize the dentin surface, to determine the effects of different pre-conditioning procedures on the elemental composition of the dentin surface, and to investigate the interaction between dentin and a dentin bonding agent (ScotchBond) by studying the changes in the elemental composition of dentin as a result of the interaction. Scanning electron microscopy (SEM) was used to characterize sample surface morphology, which was then correlated with surface elemental composition. The results showed that: (a) the elemental composition of the smear layer was similar to that of the underlying dentin; (b) cleaning with hydrogen-peroxide did not produce any modification in the elemental composition of the dentin surface; and (c) acid-etching led to an almost complete demineralization of the dentin, leaving behind an organic-rich surface. The results suggest that bonding systems that use acid-etching as a pre-conditioning procedure should be based on agents able to interact with the organic components of dentin, since bonding agents that rely on a chelation-to-calcium reaction are unlikely to be successful. The investigation of the interaction between the bonding agent and dentin led to a postulated adhesive-bonding reaction mechanism and suggested a partially cohesive failure in the bonding agent during fracturing of a dentin-bonding-agent-bonded assembly.

  11. Dentin-cement Interfacial Interaction

    Science.gov (United States)

    Atmeh, A.R.; Chong, E.Z.; Richard, G.; Festy, F.; Watson, T.F.

    2012-01-01

    The interfacial properties of a new calcium-silicate-based coronal restorative material (Biodentine™) and a glass-ionomer cement (GIC) with dentin have been studied by confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), micro-Raman spectroscopy, and two-photon auto-fluorescence and second-harmonic-generation (SHG) imaging. Results indicate the formation of tag-like structures alongside an interfacial layer called the “mineral infiltration zone”, where the alkaline caustic effect of the calcium silicate cement’s hydration products degrades the collagenous component of the interfacial dentin. This degradation leads to the formation of a porous structure which facilitates the permeation of high concentrations of Ca2+, OH-, and CO32- ions, leading to increased mineralization in this region. Comparison of the dentin-restorative interfaces shows that there is a dentin-mineral infiltration with the Biodentine, whereas polyacrylic and tartaric acids and their salts characterize the penetration of the GIC. A new type of interfacial interaction, “the mineral infiltration zone”, is suggested for these calcium-silicate-based cements. PMID:22436906

  12. Bonding over Dentin Replacement Materials.

    Science.gov (United States)

    Meraji, Naghmeh; Camilleri, Josette

    2017-08-01

    Dentin replacement materials are necessary in large cavities to protect the pulp and reduce the bulk of filling material. These materials are layered with a composite resin restorative material. Microleakage caused by poor bonding of composite resin to underlying dentin replacement material will result in pulp damage. The aim of this study was to characterize the interface between dentin replacement materials and composite resin and to measure the shear bond strength after dynamic aging. Biodentine (Septodont, Saint Maur-des-Fosses, France), Theracal LC (Bisco, Schaumburg, IL), and Fuji IX (GC, Tokyo, Japan) were used as dentin replacement materials. They were then overlaid with a total-etch and bonding agent or a self-etch primer and composite resin or a glass ionomer cement. All combinations were thermocycled for 3000 cycles. The interface was characterized using scanning electron microscopy and elemental mapping. Furthermore, the shear bond strength was assessed. The Biodentine surface was modified by etching. The Theracal LC and Fuji IX microstructure was unchanged upon the application of acid etch. The Biodentine and glass ionomer interface showed an evident wide open space, and glass particles from the glass ionomer adhered to the Biodentine surface. Elemental migration was shown with aluminum, barium, fluorine, and ytterbium present in Biodentine from the overlying composite resin. Calcium was more stable. The bond strength between Theracal LC and composite using a total-etch technique followed by self-etch primer achieved the best bond strength values. Biodentine exhibited the weakest bond with complete failure of bonding shown after demolding and thermocycling. Dynamic aging is necessary to have clinically valid data. Bonding composite resin to water-based dentin replacement materials is still challenging, and further alternatives for restoration of teeth using such materials need to be developed. Copyright © 2017 American Association of Endodontists

  13. Effect of dentinal tubule orientation on the modulus of elasticity of resin-infiltrated demineralized dentin.

    Science.gov (United States)

    Pongprueksa, Pong; Senawongse, Pisol; Vongphan, Nataya

    2014-01-01

    The effect of tubule orientation of dentin on the elastic modulus of resin-infiltrated dentin was evaluated. Rectangular cylindricalshaped dentin specimens with their long axis parallel to and perpendicular to dentinal tubules were prepared from extracted premolars. Twenty-five mineralized specimens of each orientation were evaluated. The remaining specimens were then demineralized. The demineralized specimens and the demineralized following by infiltration with one of these adhesives; Optibond Solo Plus, Single Bond 2 or Prime & Bond NT, from each orientation were evaluated (25 specimens per group). The tubular orientation only affected the elastic modulus of mineralized dentin. The highest elastic modulus was observed for the mineralized dentin when the tensile force was applied parallel to the direction of tubules. The elastic modulus of demineralized dentin was the lowest. The adhesive resins increased the elastic modulus of demineralized dentin, but the differences among the three were insignificant.

  14. Hereditary dentine disorders: dentinogenesis imperfecta and dentine dysplasia

    Directory of Open Access Journals (Sweden)

    MacKie Iain

    2008-11-01

    Full Text Available Abstract The hereditary dentine disorders, dentinogenesis imperfecta (DGI and dentine dysplasia (DD, comprise a group of autosomal dominant genetic conditions characterised by abnormal dentine structure affecting either the primary or both the primary and secondary dentitions. DGI is reported to have an incidence of 1 in 6,000 to 1 in 8,000, whereas that of DD type 1 is 1 in 100,000. Clinically, the teeth are discoloured and show structural defects such as bulbous crowns and small pulp chambers radiographically. The underlying defect of mineralisation often results in shearing of the overlying enamel leaving exposed weakened dentine which is prone to wear. Currently, three sub-types of DGI and two sub-types of DD are recognised but this categorisation may change when other causative mutations are found. DGI type I is inherited with osteogenesis imperfecta and recent genetic studies have shown that mutations in the genes encoding collagen type 1, COL1A1 and COL1A2, underlie this condition. All other forms of DGI and DD, except DD-1, appear to result from mutations in the gene encoding dentine sialophosphoprotein (DSPP, suggesting that these conditions are allelic. Diagnosis is based on family history, pedigree construction and detailed clinical examination, while genetic diagnosis may become useful in the future once sufficient disease-causing mutations have been discovered. Differential diagnoses include hypocalcified forms of amelogenesis imperfecta, congenital erythropoietic porphyria, conditions leading to early tooth loss (Kostmann's disease, cyclic neutropenia, Chediak-Hegashi syndrome, histiocytosis X, Papillon-Lefevre syndrome, permanent teeth discolouration due to tetracyclines, Vitamin D-dependent and vitamin D-resistant rickets. Treatment involves removal of sources of infection or pain, improvement of aesthetics and protection of the posterior teeth from wear. Beginning in infancy, treatment usually continues into adulthood with a

  15. Multi-factoriality of dentine hypersensitivity

    OpenAIRE

    Stojšin Ivana; Petrović Ljubomir; Stojanac Igor; Drobac Milan

    2008-01-01

    Introduction. Dentine hypersensitivity has been defined as a sharp, short pain arising from exposed dentin in response to stimuli typically thermal, evaporative tactile, osmoticor, chemical and which cannot be ascribed to any other form of dental defect or pathology. Prevalence. The most affected patients range in age from 20 to 40. The following teeth tend to be most sensitive: cuspids, premolars and incisors, location-concentrated on the facial surface. Morphological bases of dentine hypers...

  16. Dielectric response of the human tooth dentine

    Science.gov (United States)

    Leskovec, J.; Filipič, C.; Levstik, A.

    2005-07-01

    Dielectric properties of tooth dentine can be well described by the model which was developed for the dielectric response to hydrating porous cement paste. It is shown that the normalized dielectric constant and the normalized specific conductivity are proportional to the model parameters ɛ and σv, indicating the deposition of AgCl in the dentine tubules during the duration of the precipitation. The fractal dimension of the tooth dentine was determined by dielectric spectroscopy.

  17. Dielectric response of the human tooth dentine

    Energy Technology Data Exchange (ETDEWEB)

    Leskovec, J. [Dental Clinic, Faculty of Medicine, University of Ljubljana, Hrvatski trg 6, 1104 Ljubljana (Slovenia); Filipic, C. [Jozef Stefan Institute, P.O. Box 3000, 1001 Ljubljana (Slovenia); Levstik, A. [Jozef Stefan Institute, P.O. Box 3000, 1001 Ljubljana (Slovenia)]. E-mail: adrijan.levstik@ijs.si

    2005-07-15

    Dielectric properties of tooth dentine can be well described by the model which was developed for the dielectric response to hydrating porous cement paste. It is shown that the normalized dielectric constant and the normalized specific conductivity are proportional to the model parameters -bar {sub v0} and {sigma}{sub v}, indicating the deposition of AgCl in the dentine tubules during the duration of the precipitation. The fractal dimension of the tooth dentine was determined by dielectric spectroscopy.

  18. COHESIVE STRENGTH OF DENTIN RESISTÊNCIA COESIVA DA DENTINA

    OpenAIRE

    DEMARCO, Flávio Fernando; TURBINO Miriam Lacalle; MATSON Edmir

    1997-01-01

    The bond strength of dentin adhesives to dentin has increased after each generation. Although dentin substratum is part of the bonding process, little importance has been given to measure dentin cohesive strength. The aim of this study was to evaluate the cohesive strength of dentin in human canines. Seventeen non carious canines were selected. All of them had been extracted for more than one year. The teeth were ground until dentin square samples with approximately 2 X 2 mm were obtained. Th...

  19. Effect of dentine depth on the fracture toughness of dentine-composite adhesive interfaces.

    Science.gov (United States)

    Tam, L E; Yim, D

    1997-01-01

    The fracture toughness test was recently introduced as a clinically relevant method for assessing the fracture resistance of the dentine-composite interface. The objective of this study was to evaluate the effect of dentine depth on the interfacial fracture toughness test of several dentine-composite interfaces using some new proprietary dentine bonding agents. Miniature short rod fracture toughness specimens containing a chevron-shaped dentine-composite-bonded interface were prepared for each group (n = 12). Six different dentine bonding agents and two dentine depths were the variables assessed at the dentine-composite interfaces. After 24 h at 37 degrees C in water, the specimens were tested by loading at 0.5 mm/min in the Instron Universal Testing Machine. The interfacial KIC results were analysed by ANOVA, unpaired Student's t-tests and Fisher's LSD test (P dentine, respectively, were: All-Bond 2, 0.80 (0.21), 0.44 (0.13); Bond-lt, 0.75 (0.20), 0.38 (0.19); Prime and Bond, 0.56 (0.11), 0.28 (0.10); Scotchbond Multi-Purpose, 0.45 (0.23), 0.26 (0.15); One-Step and OptiBond, insufficient results due to premature specimen failures. The results from this study should contribute to the development of the fracture toughness test as a method for assessing the integrity of the dentine-composite interface. The interfacial fracture toughness test determined significant differences among the different dentine bonding agents and between the superficial and deep dentine substrates. The dentine bonding agents showed significantly reduced interfacial fracture toughness results when bonding to deep versus superficial dentine.

  20. Maturational changes in dentin mineral properties.

    Science.gov (United States)

    Verdelis, K; Lukashova, L; Wright, J T; Mendelsohn, R; Peterson, M G E; Doty, S; Boskey, A L

    2007-05-01

    In this study the changes in properties of the maturing mantle and circumpulpal dentin were quantitatively analyzed. Sections from six fetal bovine undecalcified incisors were used. Regions of mantle and circumpulpal dentin of sequential maturation stages were identified on spectroscopic images acquired by Fourier Transform Infrared Imaging. Spectroscopic parameters corresponding to mineral properties at these stages were analyzed and reported as a function of distance from the cervix of the incisor, the latter representing tissue age. Mineral parameters were correlated with distance from the cervix. Values of these parameters in mantle and circumpulpal dentin were compared. A multi-phasic pattern of changes was found for all the parameters examined, with most of the alterations occurring in the initial maturation period. The patterns of temporal variation in mantle and circumpulpal dentin mineral properties show distinct developmental stages and were not identical for the two dentin compartments. The study showed that mineral maturation in dentin is not a linear process and that mantle dentin is developmentally distinct from circumpulpal dentin, presenting at certain stages different physicochemical events during the maturation of the tissue.

  1. [Enamel and dentin under the ultrasonic microscope].

    Science.gov (United States)

    Gente, M; Matthaei, E; Mayr, P; Schwarzmann, V

    1989-01-01

    Ultrasonic reflection scanning microscopy is a new method for imaging the known structures of dental hard tissues on the basis of a simple specimen preparation. The specimens are scanned in a physiologic humid environment. Particularly high-contrast images are obtained from enamel tufts and lamellae, dentin tubules and interglobular dentin.

  2. Interaction between bioactive glasses and human dentin.

    Science.gov (United States)

    Efflandt, S E; Magne, P; Douglas, W H; Francis, L F

    2002-06-01

    This study explores the interaction between bioactive glasses and dentin from extracted human teeth in simulated oral conditions. Bioactive glasses in the Na(2)O-CaO-P(2)O(5)-SiO(2) and MgO-CaO-P(2)O(5)-SiO(2) systems were prepared as polished disks. Teeth were prepared by grinding to expose dentin and etching with phosphoric acid. A layer of saliva was placed between the two, and the pair was secured with an elastic band and immersed in saliva at 37 degrees C for 5, 21 or 42 days. The bioactive glasses adhered to dentin, while controls showed no such interaction. A continuous interface between the bioactive glass and dentin was imaged using cryogenic-scanning electron microscopy (SEM). However, after alcohol dehydration and critical point drying, fracture occurred due to stresses from dentin shrinkage. SEM investigations showed a microstructurally different material at the fractured interface. Chemical analyses revealed that ions from the glass penetrated into the dentin and that the surface of the glass in contact with the dentin was modified. Microdiffractometry showed the presence of apatite at the interface. Bonding appears to be due to an affinity of collagen for the glass surface and chemical interaction between the dentin and glass, leading to apatite formation at the interface.

  3. Microshear bonding effectiveness of different dentin regions

    Directory of Open Access Journals (Sweden)

    Anelise F Montagner

    2015-01-01

    Full Text Available Aim: The aim of this in vitro study was to evaluate the influence of dentin surfaces with different tubule orientation on bond strength of a multimode adhesive system. Materials and Methods: Twenty human molars were selected and prepared in different ways in order to produce different dentin regions. The teeth were randomized (n = 5 according to the application modes of a multimode adhesive system (etch-and-rinse and self-etching and to the dentin region (occlusal and proximal - 1.5 mm depth from dentinoenamel junction. Cylindrical restorations were performed on dentin with a starch tube. The samples remained immersed in distilled water for 24 h and the microshear bond strength (μSBS test was performed. The μSBS values were expressed in MPa and analyzed with ANOVA and Tukey′s test (P < 0.05. Results: There was no significant difference in the bond strength values between the application modes of the adhesive system (P = 0.19; however, the dentin regions (P < 0.05 significantly affected the μSBS. The proximal dentin presented higher bond strength values than occlusal dentin. Conclusion: The dentin surfaces with different tubule orientation influenced the bonding effectiveness of the adhesive system tested.

  4. Dentin hypersensitivity: prevalence, etiology, pathogenesis, and management

    NARCIS (Netherlands)

    van Loveren, C.; Schmidlin, P.R.; Martens, L.C.; Amaechi, B.T.; Amaechi, B.T.

    2015-01-01

    Dentin hypersensitivity is simply defined as a short sharply painful reaction of the exposed and innervated pulp-dentin complex in response to stimuli being typically thermal, evaporative, tactile, osmotic, or chemical and which reaction cannot be attributed to any dental defect or pathology. To be

  5. Avaliação da mortalidade por causas externas

    Directory of Open Access Journals (Sweden)

    Ricardo Alessandro Teixeira Gonsaga

    Full Text Available OBJETIVO: Avaliar os óbitos por causas externas em uma microrregião do Estado de São Paulo. MÉTODOS: Estudo descritivo exploratório transversal retrospectivo. Foi feito um levantamento e revisão de 511 prontuários das vítimas de causas externas fornecidos pelo Instituto Médico Legal de Catanduva - SP de 2008 a 2011. Os dados foram classificados por sexo, idade, intencionalidade e mecanismo de causa externa. RESULTADOS: A mortalidade foi predominante no sexo masculino, com 77,9% dos casos (p<0,001. As mortes classificadas como não intencionais representaram 66,9%, enquanto as intencionais, 33,1% (p<0,001. Os acidentes de transporte terrestre foram responsáveis por 45,6% dos casos, sendo a principal causa dos óbitos analisados. O segundo lugar foi atribuído aos suicídios, com 16%, seguido pelos homicídios (13,9%. CONCLUSÃO: Os resultados encontrados diferem dos perfis encontrados em outros estudos brasileiros, aproximando-se mais da realidade de países desenvolvidos, já que a não intencionalidade foi preponderante e as principais causas foram os acidentes de transporte terrestre, suicídios e homicídios, respectivamente. Foi constatada a necessidade de melhorias no preenchimento da declaração de óbito pelos legistas, visto que isto foi uma dificuldade encontrada pelos autores na realização do estudo.

  6. Effects of carbodiimide dentin surface treatment on resin-dentin bonding.

    Science.gov (United States)

    Haught, Yi Zhang; Tang, Lin; Liu, Yuhua; Zhou, Yongsheng; Chung, Kwok-Hung; Chan, Daniel C N

    2016-08-01

    To assess the effects of ethanol-based 1-ethyl-3-(3-dimethyl-aminopropyl) carbodiimide (EDC) dentin surface treatment on resin-dentin bonding and dentin collagen fibril biodegradation. Acid-etched dentin surfaces were pretreated with different concentrations of ethanol-based EDC solutions (0.01-2M) for 60 seconds, followed by two-step etch-and-rinse dentin adhesive application and resin composite bonding. Dentin surfaces pretreated with either ethanol alone or no pretreatment were used as controls. The specimens were subjected to microtensile bond strength testing after storage in 0.9% NaCl solution at 37°C for either 24 hours or 90 days. Furthermore, demineralized dentin slabs with and without ethanol-based EDC pretreatment were exposed to a collagenase solution for 24 hours, and subsequent hydroxyproline release was measured using ELISA. Data were analyzed with ANOVA and multiple comparison tests at α= 0.05. The bond strength values were significantly lower for dentin surfaces pretreated with 1 and 2 M ethanol-based EDC than for the control surfaces (Pbond strength values at 90 days compared to controls. Hydroxyproline release measurements revealed that there were significantly lower levels released in the 0.3 and 1 M ethanol-based EDC pretreated specimens than for controls (Pbonding can improve the stability of the resin-dentin bond and prevent dentin collagen fibril biodegradation.

  7. The influence of dentine permeability on cytotoxicity of four dentine bonding systems, in vitro.

    Science.gov (United States)

    Bouillaguet, S; Virgillito, M; Wataha, J; Ciucchi, B; Holz, J

    1998-01-01

    Dentine adhesives are often placed directly on dentine from which the smear layer has been removed, the thickness of the dentine is minimal and the potential for diffusion of adhesive components into the pulp is greatest. The permeability of the dentine is one factor that should be critical to whether sufficient diffusion of adhesive components occurs to cause damage to pulpal cells. Dentine discs were prepared and divided into those with low-, medium-, and high-permeability. They were then treated with four different dentine adhesives, after which the pulpal side of the dentine was placed in contact with 1 mL of cell-culture medium. The medium was collected at 24 h intervals for 168 h, and was then placed on monolayers of human pulpal fibroblasts for 24 h. The response of the cells was assessed by succinic dehydrogenase activity (MTT method). The results showed that four dentine adhesive systems released sufficient components to cause suppression of cellular metabolism through dentine. High-permeability dentine generally allowed more diffusion of these components, but the effect of dentine permeability depended on the material. On the other hand, the time interval between the application of the bonding agent and collection of the eluant was consistently important for all materials. Materials were most cytotoxic at early intervals, and were generally less cytotoxic at later intervals, although there were exceptions and there was persistent (> 15%) suppression of cellular metabolism even at late (168 h) intervals. The results suggest that application of these materials to dentine, and particularly dentine with high permeability, poses a potential risk to the health of pulpal tissues.

  8. The mineralization of mantle dentine and of circumpulpal dentine in the rat: an ultrastructural and element-analytical study.

    Science.gov (United States)

    Stratmann, U; Schaarschmidt, K; Wiesmann, H P; Plate, U; Höhling, H J; Szuwart, T

    1997-03-01

    The purpose of this study was to compare the biomineralization of circumpulpal dentine with that of mantle dentine by ultrastructural and element-analytical techniques. Forty upper second molar germs of 10-day-old albino rats were cryofixed in liquid nitrogen-cooled propane and embedded in resin after freeze drying. Semithin dry sections were cut for analyzing the calcium and phosphorous concentration in initial mantle dentine, at the mineralization front of circumpulpal dentine, in the middle region of circumpulpal dentine and in mantle dentine peripheral to circumpulpal dentine. For the morphological evaluation of mineral deposits we compared ultrathin and unstained sections of cryofixed molars with chemically fixed molars. For both dentine types it was found that they develop via identical steps of mineral formation at collagen fibrils and non-collagenous matrix molecules. In circumpulpal dentine no globular mineral protrusions along the mineralization front (i.e. calcospherites) and no indications of interglobular dentine at the transition from circumpulpal dentine to mantle dentine were present. Two von Korff fibres were not only visible in mantle dentine but also in circumpulpal dentine. Matrix vesicles were present only during the formation of an initial coherent layer of mantle dentine and could not be observed during successive formation of mantle dentine and circumpulpal dentine. The element-analytical data did not demonstrate any difference in the mineral content between the two dentine types. Therefore, we conclude that mantle dentine and circumpulpal dentine in the rat molar possess a high degree of structural and chemical similarity and that only the extent of terminal branching of the odontoblast processes gives an approximate estimation of the thickness of mantle dentine.

  9. Optical spectroscopy study of transparent noncarious human dentin and dentin-enamel junction

    Science.gov (United States)

    Demos, Stavros G.; Balooch, Mehdi; Marshall, Grayson W.; Marshall, Sally J.; Gallagher, R. R.

    2000-03-01

    Improving our knowledge of the morphology, composition and properties of the dentin, enamel, and the dentin-enamel junction (DEJ) is vital for the development of improved restorative materials and clinical placement techniques. Most studies of dental tissues have used light microscopy for characterization. In our investigation, the spectroscopic properties of normal and non-carious transparent human root dentin, and the dentin-enamel junction were investigated using emission imaging microscopy, and micro-spectroscopy. Experimental results reveal new information on the structural and biochemical characteristics of these dental tissues.

  10. Optical Spectroscopy Study of Transparent Non-Carious Human Dentin and Dentin-Enamel Junction

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, G.W.; Marshall, S.J.; Gallagher, R.R.; Demos, S.

    1999-12-14

    Improving our knowledge of the morphology, composition and properties of the dentin, enamel, and the dentin-enamel junction (DEJ) is vital for the development of improved restorative materials and clinical placement techniques. Most studies of dental tissues have used light microscopy for characterization. In our investigation, the spectroscopic properties of normal and non-carious transparent human root dentin, and the dentin-enamel junction were investigated using emission imaging microscopy, and micro-spectroscopy. Experimental results reveal new information on the structural and biochemical characteristics of these dental tissues.

  11. Human treated dentin matrix as a natural scaffold for complete human dentin tissue regeneration.

    Science.gov (United States)

    Li, Rui; Guo, Weihua; Yang, Bo; Guo, Lijuan; Sheng, Lei; Chen, Gang; Li, Ye; Zou, Qing; Xie, Dan; An, Xiaoxue; Chen, Yali; Tian, Weidong

    2011-07-01

    An essential aspect of tooth tissue engineering is the identification of suitable scaffolding materials to support cell growth and tissue regeneration. Treated dentin matrix (TDM) from a rat has recently been shown to be a suitable scaffold for rat dentin regeneration. However, due to species-specific differences, it remains unclear whether a similar fabrication method can be extended to human TDM and human dentin regeneration. Therefore, this present study explored the biological response to a human TDM (hTDM) created using a modified dentin treatment method. Various biological characteristics, including cell proliferation, cell migration, cell viability, and cytotoxity were investigated. To assess the inductive capacity of hTDM, dental follicle cells (DFCs) were combined with hTDM and were implanted in vivo for 8 weeks in a mouse model. The resulting grafts were studied histologically. The results showed hTDM released dentinogenic factors, indicating that hTDM could play a sustained role in odontogenesis. DFC attachment, growth, viability, and cytotoxicity on the surface of hTDM showed a notable improvement over those on calcium phosphate controls. Most importantly, in vivo hTDM induced and supported regeneration of complete dentin tissues, which expressed dentin markers DSP and DMP-1. As cells in and around the regenerated dentin were positive for human mitochondria, implanted DFCs and hTDM were responsible for the regenerated dentin tissues. In conclusion, hTDM is indicated as an ideal biomaterial for human dentin regeneration. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. Causas "fracas" e redes causais complexas em psiquiatria

    Directory of Open Access Journals (Sweden)

    Luís Fernando S. C. de Araújo

    2014-03-01

    Full Text Available OBJETIVOS: Realizamos uma análise do conceito de causalidade aplicado em psiquiatria e propomos sua abordagem baseada nas ideias de influências causais fracas e de redes causais complexas. MÉTODO: Análise conceitual de artigos e livros selecionados. RESULTADOS: Identificamos o modelo de causalidade INUS, proposto pelo filósofo J. L. Mackie que contorna algumas das dificuldades relacionadas à presença de múltiplas causas interdependentes, como parece ocorrer no caso dos transtornos mentais e mostramos que tal modelo se aplica bem ao TEPT. CONCLUSÃO: Sugerimos que o fracasso na busca de causas "fortes" para os transtornos mentais talvez indique a necessidade de revisão de nossas expectativas, com a adoção de modelos alternativos de causalidade.

  13. Effect on bonding of curing through dentin.

    Science.gov (United States)

    Uno, S; Asmussen, E

    1991-10-01

    The aim of this study was to investigate the effect of the thickness of dentin (1, 2, or 3 mm) placed between the light guide and the composite resin on the shear bond strength to dentin treated with a simplified Gluma system. The effects of the thickness of composite resin (2 or 3 mm), irradiation time (20, 40, or 60 sec), and shade (universal or brown) were also examined. The results showed that the thickness of dentin influenced bonding and interacted with the other three variables. It is suggested that dentin located between the light guide and composite resin may attenuate the light aimed at the bonding interface in the same manner as a layer of composite resin.

  14. Identification of dentin phosphophoryn localization by histochemical stainings.

    Science.gov (United States)

    Takagi, Y; Fujisawa, R; Sasaki, S

    1986-01-01

    Phosphophoryn, the most abundant of the dentin non-collagenous proteins, has been considered to be related in function to the mineralization process. In the present study, identification of dentin phosphophoryn localization was attempted using newly developed, precautionary histological methods by which phosphophoryn was retained in the sections during the specimen preparation and stained selectively in situ. Phosphophoryn was found to be present widely in all of the calcified dentin except the mantle dentin, the external, first-formed portion of dentin, but was not found in the predentin, the inner, uncalcified layer of dentin. These results indicate that phosphophoryn is apparently related to the mineral phase of calcified dentin and that the mineralization process of mantle dentin, which is formed before the odontoblasts are fully differentiated, may be different from that of circumpulpal dentin.

  15. [Multi-factoriality of dentine hypersensitivity].

    Science.gov (United States)

    Stojsin, Ivana; Petrović, Ljubomir; Stojanac, Igor; Drobac, Milan

    2008-01-01

    Dentine hypersensitivity has been defined as a sharp, short pain arising from exposed dentin in response to stimuli typically thermal, evaporative tactile, osmoticor, chemical and which cannot be ascribed to any other form of dental defect or pathology. The most affected patients range in age from 20 to 40. The following teeth tend to be most sensitive: cuspids, premnolars and incisors, location-concentrated on the facial surface. MORPHOLOGICAL BASES OF DENTINE HYPERSENSITIVITY: Sensitive teeth have much greater numbers of open tubules per unit area and the average diameter of tubules is almost 2 times greater than tubules in nonsensitive teeth. MECHANISMS OF DENTINE HYPERSENSITIVITY: The most widely accepted theory of how the pain occurs is Brannstroms theory. Dentine hypersensitivity represents a condition of presumable multifactorial pathology. Two processes are essential for its development: (1) dentin must be exposed through either genetic disturbance, enamel defect (lamellae, tufs and spindles), loss of enamel (erosion, abrasion, attrition, abfraction), gingival recession with rapid loss of cementum and (2) the dentin tubules must be open to both the oral cavity and the pulp. Diagnostic protocol for this condition consisted of Medical, Dental Dietary, Oral Hygiene History and Inra-oral examinations with air indexing method. Differential Dianosis: We must take into consideration a numnber of variables such as: dental caries, cracked tooth, restorative sensitivity, medication sensitivity, bleaching sensitivity and abscessed or non-vital tooth. Dentin hypersensitivity is a problem that bothers many patients. Many conditions share the symptoms of tooth sensitivity so differential diagnosis is essential for suitable treatment or preventive measures.

  16. Dentin Biomodification Potential Depends on Polyphenol Source

    OpenAIRE

    Aguiar, T.R.; Vidal, C.M.P.; Phansalkar, R.S.; Todorova, I.; Napolitano, J.G.; McAlpine, J.B.; Chen, S.N.; Pauli, G.F.; Bedran-Russo, A.K.

    2014-01-01

    Although proanthocyanidins (PACs) modify dentin, the effectiveness of different PAC sources and the correlation with their specific chemical composition are still unknown. This study describes the chemical profiling of natural PAC-rich extracts from 7 plants using ultra high pressure/performance liquid chromatography (UHPLC) to determine the overall composition of these extracts and, in parallel, comprehensively evaluate their effect on dentin properties. The total polyphenol content of the e...

  17. Neural elements in dental pulp and dentin.

    OpenAIRE

    Nair, P N R

    1995-01-01

    This article addresses the structural and quantitative aspects of human tooth innervation and briefly considers the functions and clinical relevance of tooth axons. The classification of peripheral axons, the pulpal and dentinal innervation, and the theories of dentin sensitivity are discussed. Quantitative studies on tooth innervation are also reviewed. Human premolars receive about 2300 axons at the root-apex of which about 13% are myelinated and 87% are nonmyelinated fibers. Most apical my...

  18. Dentine in a capsule: Clinical case reports

    OpenAIRE

    Mallikarjuna Kenchappa; Shilpi Gupta; Puneet Gupta; Priyamvada Sharma

    2015-01-01

    Biodentine TM , a calcium silicate based material has been popular now and can be used as an alternative to mineral trioxide aggregate (MTA) due to superior physical and biologic properties. It has been known by several terms as Biodentine, dentin substitute, and RD 94. It has varied clinical applications such as apexification, apexogenesis, pulpotomy, internal resorption, root perforation repair, retrograde filling, pulp capping procedure, and dentin replacement. This article describes the c...

  19. Tensile bond strength of hydroxyethyl methacrylate dentin bonding agent on dentin surface at various drying techniques

    Directory of Open Access Journals (Sweden)

    Kun Ismiyatin

    2010-06-01

    Full Text Available Background: There are several dentin surface drying techniques to provide a perfect resin penetration on dentin. There are two techniques which will be compared in this study. The first technique was by rubbing dentin surface gently using cotton pellet twice, this technique is called blot dry technique. The second technique is by air blowing dentin surface for one second and continued by rubbing dentin surface gently using moist cotton. Purpose: This experiment was aimed to examine the best dentin surface drying techniques after 37% phosphoric acid etching to obtain the optimum tensile bond strength between hydroxyethyl methacrylate (HEMA and dentin surface. Method: Bovine teeth was prepared flat to obtain the dentin surface and than was etched using 37% phosphoric acid for 15 seconds. After etching the dentin was cleaned using 20 cc plain water and dried with blot dry techniques (group I, or dried with air blow for one second (group II, or dried with air blow for one second, and continued with rubbing gently using moist cotton pellet (group III, and without any drying as control group (group IV. After these drying, the dentin surfaces were applied with resin dentin bonding agent and put into plunger facing the composite mould. The antagonist plunger was filled with composite resin. After 24 hours, therefore bond strength was measured using Autograph. Result: Data obtained was analyzed using One-Way ANOVA with 95% confidence level and continued with LSD test on p≤0.05. The result showed that the highest tensile bond strength was on group I, while the lowest on group IV. Group II and IV, III and IV, II and III did not show signigicant difference (p>0.05. Conclusion: Dentin surface drying techniques through gentle rubbing using cotton pellet twice (blot dry technique gave the greatest tensile bond strength.Latar belakang masalah: Tehnik pengeringan permukaan dentin agar resin dapat penetrasi dengan sempurna adalah dengan cara pengusapan secara

  20. Occlusion of dentin tubules with antibacterial ammonium hexafluorosilicate solution for the prevention of dentin caries.

    Science.gov (United States)

    Shibata, Shingo; Suge, Toshiyuki; Ishikawa, Kunio; Matsuo, Takashi

    2011-06-01

    To evaluate the degree of penetration of an ammonium hexafluorosilicate [SiF: (NH4)2SiF6] solution containing various antibacterial agents into dentin and the depth of dentin tubule occlusion by the precipitate. Various antibacterial SiF solutions were prepared with the addition to chlorhexidine (CHX), cetylpyridinium chloride (CPC), isopropyl methylphenol (IPMP), or epigallocatechin gallate (EGCG), respectively. Two types of dentin disks were prepared from extracted teeth. One was a dentin surface covered with a smear layer, and the other treated with EDTA for 2 minutes to remove the smear layer and open dentin tubules. Then, the disks were treated with SiF solution with or without antibacterial agents for 3 minutes. The dentin surface and a longitudinally divided surface were observed with scanning electron microscopy (SEM) immediately after SiF treatment and after immersion in synthetic saliva for 7 days. SEM photographs demonstrated that dentin tubules after treatment with SiF were occluded homogeneously and similar to those on conventional SiF treatment regardless of the addition of an antibacterial agent. However, the depth of occlusion became significantly shallower when SiF was applied to dentin specimens covered with a smear layer.

  1. Regulation of reactionary dentin formation by odontoblasts in response to polymicrobial invasion of dentin matrix.

    Science.gov (United States)

    Charadram, Nattida; Farahani, Ramin M; Harty, Derek; Rathsam, Catherine; Swain, Michael V; Hunter, Neil

    2012-01-01

    Odontoblast synthesis of dentin proceeds through discrete but overlapping phases characterized by formation of a patterned organic matrix followed by remodelling and active mineralization. Microbial invasion of dentin in caries triggers an adaptive response by odontoblasts, culminating in formation of a structurally altered reactionary dentin, marked by biochemical and architectonic modifications including diminished tubularity. Scanning electron microscopy of the collagen framework in reactionary dentin revealed a radically modified yet highly organized meshwork as indicated by fractal and lacunarity analyses. Immuno-gold labelling demonstrated increased density and regular spatial distribution of dentin sialoprotein (DSP) in reactionary dentin. DSP contributes putative hydroxyapatite nucleation sites on the collagen scaffold. To further dissect the formation of this altered dentin matrix, the associated enzymatic machinery was investigated. Analysis of extracted dentin matrix indicated increased activity of matrix metalloproteinase-2 (MMP-2) in the reactionary zone referenced to physiologic dentin. Likewise, gene expression analysis of micro-dissected odontoblast layer revealed up-regulation of MMP-2. Parallel up-regulation of tissue inhibitor of metalloproteinase-2 (TIMP-2) and membrane type 1- matrix metalloproteinase (MT1-MMP) was observed in response to caries. Next, modulation of odontoblastic dentinogenic enzyme repertoire was addressed. In the odontoblast layer expression of Toll-like receptors was markedly altered in response to bacterial invasion. In carious teeth TLR-2 and the gene encoding the corresponding adaptor protein MyD88 were down-regulated whereas genes encoding TLR-4 and adaptor proteins TRAM and Mal/TIRAP were up-regulated. TLR-4 signalling mediated by binding of bacterial products has been linked to up-regulation of MMP-2. Further, increased expression of genes encoding components of the TGF-β signalling pathway, namely SMAD-2 and SMAD-4

  2. An ion extract obtained from mineral trioxide aggregate induced dentin remineralization and dentin tubule occlusion in artificially demineralized bovine dentin.

    Science.gov (United States)

    Han, Linlin; Okiji, Takashi

    2016-06-01

    To investigate the ability of a mineral trioxide aggregate (MTA) extract mixed with a phosphate buffered saline (PBS) system to induce remineralization and dentin tubule occlusion in artificially demineralized bovine dentin. The MTA extract solution was prepared by mixing white ProRoot MTA with distilled water (1:2) for 48 hours, before subjecting it to centrifugation. The elemental composition of the MTA extract solution was analyzed with inductively coupled plasma atomic emission spectrometry. The deposits produced by the MTA extract-PBS mixture were chemically analyzed using electron probe microanalysis (EPMA) and X-ray diffraction (XRD). The effects of the two-step application of the mixture (MTA extract solution followed by PBS) to bovine dentin samples that had been artificially demineralized with phosphoric acid (10%, 10 seconds) were investigated with scanning electron microscopy and EPMA after the specimens had been stored in PBS for 1 or 7 days. The MTA extract solution contained calcium, silicone, and aluminum (Ca>Si>Al), and the deposits produced by the MTA extract-PBS mixture contained calcium, phosphorous, sodium, silicone, and aluminum (Ca>P>Na>Si>Al) as major mineral elements. XRD also revealed that the deposits contained hydroxyapatite. The two-step application process resulted in the formation of a 2-3 microm-thick "mineral infiltration layer", together with mineral tag-like structures in the dentin tubules. The MTA extract-treated specimens exhibited a significantly higher dentin tubule occlusion rate than the untreated specimens (P < 0.05).

  3. Fracture toughness of two dentin adhesives.

    Science.gov (United States)

    Howard, Kimberly; Söderholm, Karl-Johan M

    2010-12-01

    Test the hypothesis that a self-etching adhesive is more likely to fail at the dentin-adhesive interface than an etch-and-rinse adhesive. Forty-eight composite-dentin short rod chevron-notched specimens were prepared. XP Bond and G Bond were used as adhesives. After 7 days in distilled water at 37°C, each specimen was tested (cross-head speed=0.05 mm/min). Fractured surfaces were inspected and characterized as interfacial failures, composite failures or a combination of interfacial and composite failures. The fracture toughness values (K(IC)) of the two adhesives were compared (Student's t-test and Weibull statistics). Of the specimens bonded with XP Bond, 50% failed at the dentin-adhesive interface, 42% at both the dentin-adhesive and composite interface and 8% in the composite alone. Of the specimens bonded with G Bond, 41% failed at the dentin-adhesive interface, 53% at both the dentin-adhesive and composite interface and 6% in the composite alone. The K(IC) values of the two adhesives differed significantly (pBond had a K(IC) of 0.77±0.11 MNm(-3/2) (n=17), while G Bond a K(IC) of 0.62±0.21 MNm(-3/2) (n=12). The high percentage of mixed failures did not support the hypothesis that the dentin-adhesive interface is clearly less resistant to fracture than the adhesive-composite interface. The finding that cracks occurred in 6-8% in the composite suggests that defects within the composite or at the adhesive-composite interface are important variables to consider in adhesion testing. Copyright © 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  4. [N. Leonicenus interpretes of Galen on causa coniuncta].

    Science.gov (United States)

    Mugnai, Daniela

    2010-01-01

    The philosopher and physician Nicolò Leoniceno, one of the most important members of the Medical Humanism, in the N. Leoniceni in libros Galeni e Graeca in linguam Latinam a se translatos Praefatio communis (1508) discusses his emendation to Galens's Ars Medicinalis (28, 4 Boudon = I 381 Kühn, [see text]). In spite of the debatable conjecture, it is a significant effort to solve a serious contradiction in Galen's text. Leoniceno rejects the solutions proposed by the Arabic and Medieval Latin commentators and offers the right interpretation of causa coniuncta in Galen's concept of disease.

  5. Causas y consecuencias de la deficiencia de hierro

    OpenAIRE

    Olivares,Manuel; Walter,Tomás

    2004-01-01

    La deficiencia de hierro es la deficiencia nutricional más prevalente y la principal causa de anemia a escala mundial. Además de las manifestaciones propias de la anemia, se han descrito otras manifestaciones no hematológicas tales como: disminución de la capacidad de trabajo físico y de la actividad motora espontánea, alteraciones de la inmunidad celular y de la capacidad bactericida de los neutrófilos, disminución de la termogénesis, alteraciones funcionales e histológicas del tubo digestiv...

  6. La crisis del principio de taxatividad: causas y efectos

    OpenAIRE

    García, Ramón

    2015-01-01

    En la conferencia se abordaron los factores que explican que el mandato de determinación, consagrado en el art. 25.1 CE, apenas tenga efectos perceptibles en la nueva política críminal, entre otros: a) La protección de nuevos intereses como causa de indeterminación b) El cambio de paradigma en la relación entre Ley y Juez: de la legisdictio a la jurisdictio en el Estado Constitucional de Derecho. c) El mito del tenor literal posible y la prohibición de la analogía. d) La Indeterminación de...

  7. Mesenteritis esclerosante como causa excepcional de dolor abdominal

    National Research Council Canada - National Science Library

    Labalde Martínez, María; de Jaime Guijarro, José; Pacheco Martínez, Pedro; Fernández Escudero, Beatriz; Domingo Asenjo, Teresa; Jiménez de los Galanes, Santos; Castellón Pavón, Camilo; Perea Fernández, Florentino

    2011-01-01

    ... histológica mediante biopsia. A continuación se presenta un caso clínico de ME como causa excepcional de dolor abdominal. Varón de 66 años que acude a urgencias por dolor abdominal y lumbar de varios días de evolución. No presenta alteraciones del tránsito intestinal, vómitos ni fiebre. En la exploración física el abdomen es blando y depresib...

  8. How to bond to root canal dentin

    Science.gov (United States)

    Nica, Luminita; Todea, Carmen; Furtos, Gabriel; Baldea, Bogdan

    2014-01-01

    Bonding to root canal dentin may be difficult due to various factors: the structural characteristic of the root canal dentin, which is different from that of the coronal dentin; the presence of the organic tissue of the dental pulp inside the root canal, which has to be removed during the cleaning-shaping of the root canal system; the smear-layer resulted after mechanical instrumentation, which may interfere with the adhesion of the filling materials; the type of the irrigants used in the cleaning protocol; the type of the sealer and core material used in the obturation of the endodontic space; the type of the materials used for the restoration of the endodontically treated teeth. The influence of the cleaning protocol, of the root canal filling material, of the type of the adhesive system used in the restoration of the treated teeth and of the region of the root canal, on the adhesion of several filling and restorative materials to root canal dentin was evaluated in the push-out bond strength test on 1-mm thick slices of endodontically treated human teeth. The results showed that all these factors have a statistically significant influence on the push-out bond strength. Formation of resin tags between radicular dentin and the investigated materials was observed in some of the samples at SEM analysis.

  9. [Mantle dentin as biomodel of materials for structural teeth restoration].

    Science.gov (United States)

    Starodubova, A V; Vinnichenko, Yu A; Pourovskaya, I Ya; Rusanov, F S

    The article describes a structural element of natural teeth - mantle dentin. It has been shown that the presence of this element in the structure of a natural tooth largely ensures its strength under the influence of repeated loads in a functional oral environment and arrests crack growth at the enamel/dentine interface. This later effect is explained by the influence of a thin layer of mantle dentine, which has physical and mechanical characteristics different from that of the main dentin.

  10. O hipertexto e o estranho: causas e efeitos

    Directory of Open Access Journals (Sweden)

    Everton Vinicius de Santa

    2010-07-01

    Full Text Available Segundo Barthes, o texto ideal é aquele que se apresenta em redes múltiplas e que se entrelaça, sem comprometer sua estrutura. Redes ou nós que fazem com que esse texto ofereça um universo de significantes e significados, ou seja, não tem início, é reversível, possui diversas entradas e isso se choca com a noção tradicional de práticas de leitura e escrita linear. Nesse sentido, nosso objetivo é demonstrar como o hipertexto causa "estranheza" partindo do conceito de “estranho” apontado por Freud em seu artigo Das Unheimlich (1919, a fim de que possamos compreender como essa relação obra/leitor vem sendo alterada e provocando sensações de dinamicidade distintas da inércia do papel, como observamos em O Jogo da Amarelinha (1963, de Julio Cortázar, e em textos de temática fantástica, como em E.T.A. Hoffmann e Edgar Allan Poe, não no sentido do assustador, mas do provocativo, do foregrounding que gera causas e efeitos significantes nas práticas literárias digitais conectadas ao ciberespaço.

  11. The effect of dentin-cleaning agents on resin cement bond strength to dentin.

    Science.gov (United States)

    Saraç, Duygu; Bulucu, Bilinc; Saraç, Y Sinasi; Kulunk, Safak

    2008-06-01

    Provisional cement remnants on dentin affect the bond strength of resin cements to dentin. The authors investigated the effects of dentin-cleaning agents and etching systems on the bond strength of adhesive resin cement. The authors removed the provisional cement from the dentin surfaces of the specimens and then cleaned the surfaces with the dentin-cleaning agents Sikko Tim (VOCO GmbH, Cuxhaven, Germany), Cavity Cleanser (Bisco, Schaumburg, Ill.) or Consepsis Scrub (Ultradent, South Jordan, Utah). They used adhesive resin cement after applying the different etching adhesive systems. Then they examined the dentin surfaces by using scanning electron microscopy. The authors analyzed data by means of a two-way analysis of variance with Tukey honestly significant difference tests (alpha= .05). They found that specimens cleaned with Sikko Tim and Consepsis Scrub had higher shear bond strength values than did those in the no-treatment control group or the group cleaned with Cavity Cleanser. The specimens treated with the total-etching adhesive system had higher shear bond strength than did those treated with the self-etching adhesive systems. Sikko Tim and Consepsis Scrub were effective in removing provisional cement. Adhesive resin cement showed higher bond strength when used in conjunction with the total-etching adhesive system. The use of an effective dentin cleaner before cementation with resin cement can increase bond strength.

  12. Causas de morte de doentes internados por tuberculose

    Directory of Open Access Journals (Sweden)

    L. Mota

    1996-11-01

    Full Text Available Resumo: Apesar da tuberculose ser uma doença curável, assistimos com alguma frequência à morte de doentes internndos no departamento de Pneumologia do Hospital de Pulido Valente com esta afecção. Resolvemos analisar a causa de morte de 26 doeontes internados nos anos de 1993 e 1994.Procurouse analisar·as presumiveis causas de morte destes 26 doentes, predomínantemente do sexo masculino (88%, raça caucasiana (81 % com idade média de 54,4 anos. Salientamos que 50% tinham hábitos alcoólicos e história prévia de tuberculose. Tinham patologia associada 42%, sendo a DPOC a mais frequente. Tinham seropositividade para o VIH 41,6%, donça disseminada 54% e atingimento radiológico do tórax muito extenso 62%. Qnanto às causas de morte, em 10 doentes encontrámos outras causas que não a tuberculose e tm 16 foi accite o tuberculose. Entre estes, Seram seropositivus, 6 tinham doença disseminda, 4 tinham formas muito extensas e 3 idade superior a 75 anos. Um doente faleceu com uma hemoptise fulminante.Salientamos que o elevado númcro de falecidus com hábitos alcoó1icos e de toxicofilia, poderiam justificar·uma menor adesão an tratameuto e dai uma maior mortalidade. A morte por tuberculose foi mais frequente entre as formas mals extensas e as formas disseminadas. ABSTRACT: Although tuberculosis is a curable disease, some patients still died from it. We analysed the cause of death 26 patients who died with tuberculosis in our Department.Male (88% and caucasian (81 % with a mean age of 54.4 years old were the most frequent patients in our review. Fifty Percent were alcoholic and bad a previous history of tuberculosis. 42% patients had associated disease, predominantly COPD. HIV seropositivity existed in 41.6%, disseminated disease in 54% and 62% had a very extense pulmonary tuberculosis. Among causes of death, in 10 patients it was due to other causes and in 16 tuberculosis was admitted as the cause of death: 5 patients were HIV positive

  13. SHRINKAGE OF SOUND AND DEMINERALIZED HUMAN CORONAL DENTIN SLABS

    NARCIS (Netherlands)

    RUBEN, J; ARENDS, J

    1993-01-01

    In this article a method is presented for dentine shrinkage measurements. The relative shrinkage of sound dentine slabs is assessed using a Perthometer with respect to a steel reference. The relative shrinkage of lesions in dentine slabs can be estimated using combined Perthometer/microradiography

  14. Micromorphological Evaluation of Dentin Treated with Different Desensitizing Agents

    OpenAIRE

    Osmari, Deise; de Oliveira Ferreira, Ana Carolina; de Carlo Bello, Mariana; Henrique Susin, Alexandre; Cecília Correa Aranha, Ana; Marquezan, Marcela; Lopes da Silveira, Bruno

    2013-01-01

    Introduction: The purpose of a desensitizing agent is a permanent coating or filling of dentin surface. Morphological analysis in vitro of this treated surface is essential to understand the interaction between desensitizing agent and hypersensitive dentin. The aim was to evaluate the morphology of four dentin surface treated with desensitizing agents.

  15. Plasma treatment of dentin surfaces for improving self-etching adhesive/dentin interface bonding

    Science.gov (United States)

    Dong, Xiaoqing; Li, Hao; Chen, Meng; Wang, Yong; Yu, Qingsong

    2015-01-01

    This study is to evaluate plasma treatment effects on dentin surfaces for improving self-etching adhesive and dentin interface bonding. Extracted unerupted human third molars were used after crown removal to expose dentin. One half of each dentin surface was treated with atmospheric non-thermal argon plasmas, while another half was untreated and used as the same tooth control. Self-etching adhesive and universal resin composite was applied to the dentin surfaces as directed. After restoration, the adhesive-dentin bonding strength was evaluated by micro-tensile bonding strength (μTBS) test. Bonding strength data was analyzed using histograms and Welch’s t-test based on unequal variances. μTBS test results showed that, with plasma treatment, the average μTBS value increased to 69.7±11.5 MPa as compared with the 57.1±17.5 MPa obtained from the untreated controls. After 2 months immersion of the restored teeth in 37 °C phosphate buffered saline (PBS), the adhesive-dentin bonding strengths of the plasma-treated specimens slightly decreased from 69.7±11.5 MPa to 63.9±14.4 MPa, while the strengths of the untreated specimens reduced from 57.1±17.5 MPa to 48.9±14.6 MPa. Water contact angle measurement and scanning electron microscopy (SEM) examination verified that plasma treatment followed by water rewetting could partially open dentin tubules, which could enhance adhesive penetration to form thicker hybrid layer and longer resin tags and consequently improve the adhesive/dentin interface quality. PMID:26273561

  16. Dentin Matrix Proteins in Bone Tissue Engineering.

    Science.gov (United States)

    Ravindran, Sriram; George, Anne

    2015-01-01

    Dentin and bone are mineralized tissue matrices comprised of collagen fibrils and reinforced with oriented crystalline hydroxyapatite. Although both tissues perform different functionalities, they are assembled and orchestrated by mesenchymal cells that synthesize both collagenous and noncollagenous proteins albeit in different proportions. The dentin matrix proteins (DMPs) have been studied in great detail in recent years due to its inherent calcium binding properties in the extracellular matrix resulting in tissue calcification. Recent studies have shown that these proteins can serve both as intracellular signaling proteins leading to induction of stem cell differentiation and also function as nucleating proteins in the extracellular matrix. These properties make the DMPs attractive candidates for bone and dentin tissue regeneration. This chapter will provide an overview of the DMPs, their functionality and their proven and possible applications with respect to bone tissue engineering.

  17. Dentine microhardness after different methods for detection and removal of carious dentine tissue

    Directory of Open Access Journals (Sweden)

    Fernanda Brandão Mollica

    2012-08-01

    Full Text Available There are several methods for identifying carious dentinal tissue aiming to avoid removal of healthy dentinal tissue. OBJECTIVES: The purpose of this study was to test different methods for the detection of carious dentinal tissue regarding the amount of carious tissue removed and the remaining dentin microhardness after caries removal. MATERIAL AND METHODS: The dentin surfaces of 20 bovine teeth were exposed and half of the surface was protected with nail polish. Cariogenic challenge was performed by immersion in a demineralizing solution for 14 days. After transverse cross-section of the crown, the specimens were divided into four groups (n=10, according to the method used to identify and remove the carious tissue: "Papacárie", Caries-detector dye, DIAGNOdent and Tactile method. After caries removal, the cross-sectional surface was included in acrylic resin and polished. In a microhardness tester, the removed dentin thickness and the Vickers microhardness of the following regions were evaluated: remaining dentin after caries removal and superficial and deep healthy dentin. RESULTS: ANOVA and Tukey's test (α=0.05 were performed, except for DIAGNOdent, which did not detect the presence of caries. Results for removed dentin thickness were: "Papacárie" (424.7±105.0; a, Caries-detector dye (370.5±78.3; ab, Tactile method (322.8±51.5; bc. Results for the remaining dentin microhardness were: "Papacárie" (42.2±10.5; bc, Caries-detector dye (44.6±11.8; abc, Tactile method (24.3±9.0; d. CONCLUSIONS: DIAGNOdent did not detect the presence of carious tissue; Tactile method and "Papacárie" resulted in the least and the most dentinal thickness removal, respectively; Tactile method differed significantly from "Papacárie" and Caries-detector dye in terms of the remaining dentin microhardness, and Tactile method was the one which presented the lowest microhardness values.

  18. Dentine in a capsule: Clinical case reports

    Directory of Open Access Journals (Sweden)

    Mallikarjuna Kenchappa

    2015-01-01

    Full Text Available Biodentine TM , a calcium silicate based material has been popular now and can be used as an alternative to mineral trioxide aggregate (MTA due to superior physical and biologic properties. It has been known by several terms as Biodentine, dentin substitute, and RD 94. It has varied clinical applications such as apexification, apexogenesis, pulpotomy, internal resorption, root perforation repair, retrograde filling, pulp capping procedure, and dentin replacement. This article describes the clinical case reports using Biodentine in apexification, apexogenesis, pulpotomy, and root perforation repair.

  19. Dentine in a capsule: clinical case reports.

    Science.gov (United States)

    Kenchappa, Mallikarjuna; Gupta, Shilpi; Gupta, Puneet; Sharma, Priyamvada

    2015-01-01

    Biodentine TM , a calcium silicate based material has been popular now and can be used as an alternative to mineral trioxide aggregate (MTA) due to superior physical and biologic properties. It has been known by several terms as Biodentine, dentin substitute, and RD 94. It has varied clinical applications such as apexification, apexogenesis, pulpotomy, internal resorption, root perforation repair, retrograde filling, pulp capping procedure, and dentin replacement. This article describes the clinical case reports using Biodentine in apexification, apexogenesis, pulpotomy, and root perforation repair.

  20. Obesidade infantil: causas e estratégias preventivas

    Directory of Open Access Journals (Sweden)

    Vanessa Margareth Soares

    2015-04-01

    Full Text Available Esta pesquisa teve como objetivo auxiliar a compreensão das causas da obesidade infantil bem como mostrar algumas estratégias simples que podem contribuir na prevenção dessa doença. O caso ‘sobrepeso e obesidade’ é tratado por muitas pessoas sem a devida importância, por entenderem que o mesmo é apenas uma questão estética que não interfere em nada além da saúde física da criança obesa ou sobrepesada, o que é um engano, pois a obesidade e o sobrepeso tem várias causas e uma extensão de problemas, como a hipertensão e o diabetes entre outros, que estão associados direta ou indiretamente a esse mal. A pesquisa foi realizada com crianças de 4 a 5 anos, de uma escola pública e uma privada do município de Sinop - MT, tendo como respaldo metodológico a observação participante utilizando-se de questionários implícitos em diálogos, onde tivemos a oportunidade de compreender alguns aspectos sobre os hábitos alimentares e físicos das mesmas. Os diálogos foram analisados de forma qualitativa, onde munidos do índice de massa corporal, caderno de impressões, podemos constatar que o maior mal que a obesidade causa é o psicológico, pois as crianças sobrepesadas observadas se excluem do convívio social. Aos responsáveis e sociedade em geral cabe a responsabilidade de dar continuidade aos saberes aplicados em sala, estabelecendo hábitos mais saudáveis no ambiente em que vivem.Palavras-chave: educação; educação física e alimentar; obesidade infantil; alunos de 4 e 5 anos.

  1. Spectroscopic imaging of mineral maturation in bovine dentin.

    Science.gov (United States)

    Verdelis, K; Crenshaw, M A; Paschalis, E P; Doty, S; Atti, E; Boskey, A L

    2003-09-01

    Dentin is a useful model for the study of mineral maturation. Using Fourier Transform Infrared Imaging (FTIRI), we characterized distinct regions in developing dentin at 7- micro m spatial resolution. Mineral-to-matrix ratio and crystallinity in bovine dentin from cervical and incisal parts of 3rd-trimester fetal compared with one-year-old incisor crowns showed that virtually all maturation stages in dentin could be spectroscopically isolated and analyzed. In the fetal incisors, mantle and circumpulpal dentin presented distinct patterns of mineral maturation. Gradients in both mineral properties examined were observed at the mineralization front and at the dentino-enamel junction.

  2. Transmission electron microscopic characterization of hypersensitive human radicular dentin

    Energy Technology Data Exchange (ETDEWEB)

    Yoshiyama, M.; Noiri, Y.; Ozaki, K.; Uchida, A.; Ishikawa, Y.; Ishida, H. (Tokushima Univ. School of Dentistry (Japan))

    1990-06-01

    Transmission electron microscopy (TEM) and x-ray microanalysis (XMA) were used for the study of the ultrastructure of the lumens of dentinal tubules in superficial layers of dentin specimens obtained by use of a new biopsy technique from both hypersensitive and naturally desensitized areas of exposed root surfaces, in vivo. The TEM images showed clearly that the lumens of most of the tubules were occluded with mineral crystals in naturally desensitized areas, but such lumens were empty and surrounded with peritubular and intertubular dentin in hypersensitive areas. Moreover, electron-dense structures that lined peritubular dentin were observed in the empty lumens of dentinal tubules.

  3. Prismatic dentine in the Australian lungfish, Neoceratodus forsteri (Osteichthyes: Dipnoi).

    Science.gov (United States)

    Kemp, Anne; Barry, John C

    2006-04-01

    The Australian lungfish, Neoceratodus forsteri, has a dentition consisting of enamel, mantle dentine and bone, enclosing circumdenteonal, core and interdenteonal dentines. Branching processes from cells that produce interdenteonal dentine leave the cell surface at different angles, with collagen fibrils aligned parallel to the long axis of each process. In the interdenteonal dentine, crystals of calcium hydroxyapatite form within fibrils of collagen, and grow within a matrix of non-collagenous protein. Crystals are aligned parallel to the cell process, as are the original collagen fibrils. Because the processes are angled to the cell surface, the crystals within the core or interdenteonal dentine are arranged in bundles set at angles to each other. Apatite crystals in circumdenteonal dentine are finer and denser than those of the interdenteonal dentine, and form outside the fibrils of collagen. In mature circumdenteonal dentine the crystals of circumdenteonal dentine form a dense tangled mass, linked to interdenteonal dentine by isolated crystals. The functional lungfish tooth plate contains prisms of large apatite crystals in the interdenteonal dentine and masses of fine tangled crystals around each denteon. This confers mechanical strength on a structure with little enamel that is subjected to heavy wear.

  4. A biofilm cariogenic challenge model for dentin demineralization and dentin bonding analysis.

    Science.gov (United States)

    Maske, Tamires T; Isolan, Cristina P; van de Sande, Françoise H; Peixoto, Aline C; Faria-E-Silva, André L; Cenci, Maximiliano S; Moraes, Rafael R

    2015-06-01

    This study was designed to adapt a previously developed in vitro microcosm biofilm model to create carries-affected dentin (CAD) and establish conditions for using the model in bonding studies. Biofilms were originated from human saliva and grown on dentin discs for 0 (sound dentin), 3, 5, 7, 14, or 21 days under intermittent cariogenic condition (n = 10). At each time point, composite cylinders were bonded to the dentin using self-etch adhesive (Clearfil SE Bond). The response variables were integrated mineral loss (ΔS), lesion depth (LD), shear bond strength (SBS), and failure mode. Data were statistically analyzed (α = 0.05). Bonded interfaces were analyzed by scanning electron microscopy (SEM), and dentin surfaces characterized by infrared spectroscopy (Fourier transform infrared spectroscopy, FTIR). Lower ΔS was found for sound dentin than for CAD in all experimental groups, except for the group under cariogenic challenge for 3 days. The SBS to CAD was significantly lower than control for all cariogenic challenge times. Adhesive failures were predominant in all groups. ΔS and LD had a significant negative correlation with SBS. A significant exponential decay in SBS was associated with increased ΔS values. CAD had lower mineral and amide I content and an irregular hybridization interface compared to sound dentin. The microcosm biofilm model was able to artificially induce CAD, which imposed challenge to the bonding of the polymeric adhesive material. Presence of CAD might interfere with the bonding of polymeric materials. The microcosm biofilm model proposed could be useful for preclinical dentin bonding studies.

  5. Nanoindentation hardness of intertubular dentin in sound, demineralized and natural caries-affected dentin.

    Science.gov (United States)

    Joves, Gerardo José; Inoue, Go; Sadr, Alireza; Nikaido, Toru; Tagami, Junji

    2014-04-01

    The purpose of this study was to investigate the mechanical properties of intertubular dentin in sound, natural caries-affected (NCAD) and artificial caries-affected dentin (ACAD) using nanoindentation. Non-caries molars and caries molars with International Caries Detection and Assessment System (ICDAS II) score 5 at the occlusal site were used and caries was excavated using a spoon excavator, a round bur at low speed without water and a dye solution as guidance to detect the infected tissue. Specimens with remaining dentin thickness (RDT) >2mm were selected. ACAD teeth were created from sound teeth over 7 days in a demineralizing solution. Specimens were embedded into plastic rings with acrylic resin and then sagittal mesial-distal sectioned from crown to the long axis of the root under cooling water using a low-speed diamond blade. The surface of interest was fine polished sequentially. Hardness measurement was performed within an axial depth of 1000μm with at least of 320 indentations on each sample. Mann-Whitney U Test was used to compare the hardness as the variable among different dentin types (SOUND, NCAD and ACAD) at each dentin depth level. There was no significant difference in nanohardness between NCAD and ACAD up to a depth of 130μm (p>0.05). NCAD consistently showed lower hardness. ACAD showed no significant difference in hardness with SOUND dentin beyond 190μm (phardness; however the long-term effects of caries beneath the lesion extend deeply through intertubular dentin. Sound dentin at deep areas (close to the pulp chamber) is considered to be soft. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Effect of Nanofiller Addition to an Experimental Dentin Adhesive on Microtensile Bond Strength to Human Dentin

    Directory of Open Access Journals (Sweden)

    SH. Kasraei

    2009-06-01

    Full Text Available Objective: The purpose of the study was to evaluate the influence of adding nanofiller particles to a dentin bonding agent on resin-dentin bond strength.Materials and Methods: Fifty-four human intact premolar teeth were divided in to 6 groups of nine. The teeth were ground on occlusal surfaces and polished with 320 and then 600 grit silicon carbide papers. An experimental bonding system based on acetone/alcoholsolvent was provided with filler contents of 0.0, 0.5, 1.0, 2.5, 5.0, and 10.0 weight percent fumed silica nanofiller. After dentin surface etching, rinsing and blot drying, the experimentalbonding agents were applied to dentin surface. A composite resin was, then,bonded to the dentin on the bonding agent. The specimens were thermocycled for 500 cycles and sectioned in stick form. After two week of storage in distilled water, resin-dentin microtensile bond strength of the specimens was measured. Data were analyzed by one way ANOVA and DunnettT3 tests.Results: Bond strength to dentin was significantly affected by the filler level. Minimum and maximum resin-microtensile bond strength was in the experimental bonding agent with no filler (5.88 MPa and with filler level of 1.0 weight percent (15.15 MPa, respectively,and decreased with the increase of filler content down to 8.95 MPa for the filler level of 10.0 weight percent.Conclusion: Filler content seems to be one of the important factors influencing the bond strength of dental adhesives. Maximum dentin bond strength was obtained with 1% silanized nanofiller silica added to experimental adhesive system.

  7. Histological distribution of phosphophoryn in normal and pathological human dentins.

    Science.gov (United States)

    Takagi, Y; Sasaki, S

    1986-10-01

    Dentin phosphophoryn is a highly phosphorylated protein which has a hydrophilic character but is not soluble in dilute acetic acid. A histochemical method was developed for staining this protein with Stains-all in situ utilizing those chemical properties. We have succeeded in detecting the presence of this protein in circumpulpal orthodentin of human permanent and deciduous teeth, but not in mantle dentin, secondary dentin and reparative dentin. Phosphophoryn staining was also absent in the dentin of dentinogenesis imperfecta (DI) Type II, a genetic disorder of dentin formation. From these results, it is suggested that phosphophoryn is synthesized and secreted only by physiologically-differentiated odontoblasts and that the mineralization processes of mantle, secondary, reparative and DI dentins may be different from that of circumpulpal orthodentin.

  8. Effects of endodontic tri-antibiotic paste on bond strengths of dentin adhesives to coronal dentin

    Directory of Open Access Journals (Sweden)

    Parvin Mirzakoucheki

    2015-05-01

    Full Text Available Objectives The aim of this study was to evaluate the effects of tri-antibiotic paste (TAP on microtensile bond strengths (MTBS of dental adhesives to dentin. Materials and Methods Sixty extracted molars had their occlusal surfaces flattened to expose dentin. They were divided into two groups, i.e., control group with no dentin treatment and experimental group with dentin treatment with TAP. After 10 days, specimens were bonded using self-etch (Filtek P90 adhesive or etch-and-rinse (Adper Single Bond Plus adhesives and restored with composite resin. Teeth were sectioned into beams, and the specimens were subjected to MTBS test. Data were analyzed using two-way ANOVA and post hoc Tukey tests. Results There was a statistically significant interaction between dentin treatment and adhesive on MTBS to coronal dentin (p = 0.003. Despite a trend towards worse MTBS being noticed in the experimental groups, TAP application showed no significant effect on MTBS (p = 0.064. Conclusions The etch-and-rinse adhesive Adper Single Bond Plus presented higher mean bond strengths than the self-etch adhesive Filtek P90, irrespective of the group. The superior bond performance for Adper Single Bond when compared to Filtek P90 adhesive was confirmed by a fewer number of adhesive failures. The influence of TAP in bond strength is insignificant.

  9. SEM evaluation of resin-carious dentin interfaces formed by two dentin adhesive systems.

    Science.gov (United States)

    Hsu, Kuang-Wei; Marshall, Sally J; Pinzon, Lilliam M; Watanabe, Larry; Saiz, Eduardo; Marshall, Grayson W

    2008-07-01

    We investigated the influence of dentin tubule direction and identifiable zone of carious dentin on the microstructure and the thickness of the hybrid-like layer (HL) formed by self-etch and etch-rinse adhesive systems. An etch-rinse and a self-etching adhesive were bonded to dentin carious zones divided into groups with parallel or perpendicular orientation relative to the dentin tubules at the resin-carious dentin interface (N=5/variable). Bonds were prepared to each of the four zones of carious dentin apparent after staining with Caries Detector: pink, light pink, transparent and apparently normal; six non-carious third molars were controls. The microstructure and thickness of the HL were determined by SEM and compared using three-way ANOVA and Tukey's multiple comparisons (pbonded with the etch-rinse system. For both adhesives, HL thickness in the pink zone was significantly greater than in light pink for the perpendicular group, but no significant differences were found among other variables. HL microstructure was more granular and rougher for the etch-rinse than for the self-etching system. Pores and cracks were obvious in the more demineralized zones. Resin tags were shorter and irregular in the transparent zone and often were completely absent in the outer demineralized zones (pink, light pink). Microstructure of bonded interfaces varies markedly depending on adhesive system, tubule orientation and carious zone.

  10. Effect of dentin conditioning on bond strength of fiber posts and dentin morphology: a review.

    Science.gov (United States)

    Khalighinejad, Navid; Feiz, Atiyeh; Faghihian, Reyhaneh; Swift, Edward J

    2014-02-01

    Post and core systems are commonly used to restore endodontically treated teeth. A durable bond between fiber posts and dentin contributes to the success of the restorative treatment. Different irrigants are used during post space preparation and various studies have investigated the effects of these chemical agents on bond strength and dentin morphology. The MEDLINE-PubMed, Cochrane, and SCOPUS databases were searched for appropriate papers addressing the effects of irrigants on bonding of fiber posts to dentin and on dentin morphology. Databases were searched from 2002 through 2012. The search was performed using a variety of keywords including fiber posts, bond strength, post space preparation, post space irrigation, and smear layer removal. Using multiple key words and different strategies, 68 publications were initially screened. The abstracts of these 68 publications were scanned for relevance, and 50 full-text articles were selected and read in detail. Thirty publications which discussed the effect of various intracanal irrigants on bond strengths of fiber posts and dentin morphology were incorporated in this review. Following review of all relevant papers, it can be concluded that bond strengths of fiber posts to radicular dentin can be affected by the irrigants used and that various irrigants affect different types of resin cements differently.

  11. La renovación del concepto de causa en el derecho francés

    Directory of Open Access Journals (Sweden)

    Margarita Morales Huertas

    2009-06-01

    Full Text Available Sumario: Premisa. i. La economía del contrato y la causa de la obligación. A. El interés del contrato: causa y grupos contractuales. B. Causa y coherencia contractual: protección al profesional contra las cláusulas abusivas. ii. Licitud de la causa: interés general y liberalización de costumbres. A. El conocimiento por una sola de las partes del contrato acerca del motivo determinante ilícito o inmoral. B. La liberalización de las buenas costumbres. iii. Conclusión

  12. Dentin Dysplasia in Notum Knockout Mice.

    Science.gov (United States)

    Vogel, P; Read, R W; Hansen, G M; Powell, D R; Kantaputra, P N; Zambrowicz, B; Brommage, R

    2016-07-01

    Secreted WNT proteins control cell differentiation and proliferation in many tissues, and NOTUM is a secreted enzyme that modulates WNT morphogens by removing a palmitoleoylate moiety that is essential for their activity. To better understand the role this enzyme in development, the authors produced NOTUM-deficient mice by targeted insertional disruption of the Notum gene. The authors discovered a critical role for NOTUM in dentin morphogenesis suggesting that increased WNT activity can disrupt odontoblast differentiation and orientation in both incisor and molar teeth. Although molars in Notum(-/-) mice had normal-shaped crowns and normal mantle dentin, the defective crown dentin resulted in enamel prone to fracture during mastication and made teeth more susceptible to endodontal inflammation and necrosis. The dentin dysplasia and short roots contributed to tooth hypermobility and to the spread of periodontal inflammation, which often progressed to periapical abscess formation. The additional incidental finding of renal agenesis in some Notum (-/-) mice indicated that NOTUM also has a role in kidney development, with undiagnosed bilateral renal agenesis most likely responsible for the observed decreased perinatal viability of Notum(-/-) mice. The findings support a significant role for NOTUM in modulating WNT signaling pathways that have pleiotropic effects on tooth and kidney development. © The Author(s) 2016.

  13. Penetration of amalgam constituents into dentine.

    NARCIS (Netherlands)

    Scholtanus, J.D.; Ozcan, M.; Huysmans, M.C.D.N.J.M.

    2009-01-01

    OBJECTIVES: Amalgam restorations are replaced by adhesively placed composite resin restorations at an increasing rate. After the removal of amalgam dentine often shows marked dark discoloration that is attributed to the penetration of corrosion products from overlying amalgams. It is questioned

  14. Penetration of amalgam constituents into dentine

    NARCIS (Netherlands)

    Scholtanus, Johannes D.; Ozcan, Mutlu; Huysmans, Marie-Charlotte D. N. J. M.

    Objectives: Amalgam restorations are replaced by adhesively placed composite resin restorations at an increasing rate. After the removal of amalgam dentine often shows marked dark discoloration that is attributed to the penetration of corrosion products from overlying amalgams. it is questioned

  15. Creep and Viscoelastic Behaviour of Human Dentin

    Directory of Open Access Journals (Sweden)

    T.Jafarzadeh

    2004-03-01

    Full Text Available Statement of Problem: Biomechanics of the human dentition is inherently complex.Purpose: The aim of this study is to investigate, in vitro, the creep and the recovery of dentin under static uniaxial compressive stress conditions.Materials and Methods: Specimens of cylindrical morphology were prepared from recently extracted non-carious lower molar teeth, such that the average tubule orientation was axial. Slides of mid- coronal dentin (parallel surfaces, height 1.8 mm were sectionedwith a slow speed diamond saw and then cut into cylindrical discs. Specimens were stored at 4ºC for 24h to restabilize water content. Creep data were then measured by LVDT axially in water for periods of 2h load + 2h recovery on 4 separate groups (n=6: at two stresses (10 & 18 MPa and at two temperatures: 37 & 60ºC. Maximum creep strain, permanent set,strain recovery and initial compressive modulus were reported.Results: Compliance values were also calculated and slight non-linearity found at 60ºC.Two-way ANOVA was performed on results. Dentin exhibited a linear viscoelastic response under 'clinical' compressive stress levels , with a maximum strain ~ 1% and highrecoverability: permanent set<0.3%.Conclusion: This established a performance standard for viscoelastic stability of restorative biomaterials, replacing human dentin.

  16. Dentin biomodification potential depends on polyphenol source.

    Science.gov (United States)

    Aguiar, T R; Vidal, C M P; Phansalkar, R S; Todorova, I; Napolitano, J G; McAlpine, J B; Chen, S N; Pauli, G F; Bedran-Russo, A K

    2014-04-01

    Although proanthocyanidins (PACs) modify dentin, the effectiveness of different PAC sources and the correlation with their specific chemical composition are still unknown. This study describes the chemical profiling of natural PAC-rich extracts from 7 plants using ultra high pressure/performance liquid chromatography (UHPLC) to determine the overall composition of these extracts and, in parallel, comprehensively evaluate their effect on dentin properties. The total polyphenol content of the extracts was determined (as gallic acid equivalents) using Folin-Ciocalteau assays. Dentin biomodification was assessed by the modulus of elasticity, mass change, and resistance to enzymatic biodegradation. Extracts with a high polyphenol and PAC content from Vitis vinifera, Theobroma cacao, Camellia sinensis, and Pinus massoniana induced a significant increase in modulus of elasticity and mass. The UHPLC analysis showed the presence of multiple types of polyphenols, ranging from simple phenolic acids to oligomeric PACs and highly condensed tannins. Protective effect against enzymatic degradation was observed for all experimental groups; however, statistically significant differences were observed between plant extracts. The findings provide clear evidence that the dentin bioactivities of PACs are source dependent, resulting from a combination of concentration and specific chemical constitution of the complex PAC mixtures.

  17. Hydrofluoric acid on dentin should be avoided.

    NARCIS (Netherlands)

    Loomans, B.A.C.; Mine, A.; Roeters, F.J.M.; Opdam, N.J.M.; Munck, J. De; Huysmans, M.C.D.N.J.M.; Meerbeek, B. Van

    2010-01-01

    Hydrofluoric acid can be used for intra-oral repair of restorations. Contamination of tooth substrate with hydrofluoric acid cannot always be avoided. OBJECTIVES: To investigate the bonding effectiveness to hydrofluoric acid contaminated dentin by, micro-tensile bond strength testing, SEM and TEM.

  18. Different enzyme extraction methods for human dentin

    National Research Council Canada - National Science Library

    Fernando Nato; Alberto Bavelloni; Alessandra Ruggeri; Pietro Gobbi; Lorenzo Breschi

    2010-01-01

    ... The purpose of this study was to analyze different enzymes extraction methods in relation to the assay to be performed, i.e. zymography and western blotting (WB) for MMP-2 and -9. Methods Proteins were extracted from human dentin powder and demineralized with 1% phosphoric acid for 10min. Two different extraction buffers with different extrac...

  19. Resin diffusion through demineralized dentin matrix

    Directory of Open Access Journals (Sweden)

    CARVALHO Ricardo M.

    1999-01-01

    Full Text Available This paper has focused on the factors that may affect the permeability of adhesive resins into the demineralized dentin matrix during the development of the bonding process. The effects of surface moisture are discussed respectively to the adhesive systems, and the problems related to incomplete hybrid layer formation presented.

  20. Dentine hypersensitivity: real or imagined | Gbadebo | Nigerian ...

    African Journals Online (AJOL)

    Background: Dentine hypersensitivity is a common presentation of cause of pain and or discomfort with mastication which has been shown to affect the quality of life of the affected individual. It is also a common cause of presentation at the dental clinics. However, the cause, diagnosis and possible management to give relief ...

  1. Morphometric computerized analysis on the dentinal tubules and the collagen fibers in the dentine of human permanent teeth.

    Science.gov (United States)

    Marchetti, C; Piacentini, C; Menghini, P

    1992-01-01

    A morphometric analysis has been performed on important components of human dentine using an image computerized analyzer. The dentinal tubule diameter and their area percentage were calculated. Moreover the area percentage of the collagen fibers in the dentinal matrix was measured. These parameters have been evaluated in different areas of the coronal and the radicular dentine in permanent teeth. Measurements have been performed on undecalcified and decalcified teeth and on teeth treated with enzymatic digestion to remove the organic non collagen matrix and to evidentiate the collagen fiber network. The values obtained in different areas of the tooth and in samples submitted to different treatments were evaluated by statistical analysis. Dentinal tubule diameter and area percentage significatively decrease from the inner to the peripheral dentine both in the undecalcified teeth as in the decalcified ones and in the samples undergone to enzymatic digestion. The collagen fiber percentage in the organic matrix is significatively lower in the mantle dentine.

  2. The Possible Role of Dentin as a Piezoelectric Signal Generator by Determining the Elec-tromechanical Coupling Factor of Dentin

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    Atabak Shahidi

    2011-08-01

    Full Text Available Introduction: This article aimed at calculation of the electromechanical coupling factor of dentin which is an indicator of the effectiveness with which a piezoelectric material converts electrical en-ergy into mechanical energy, or vice versa. The hypothesis: The electro-mechanical coupling factor of dentin was determined in mode 11 and 33 by calculating the ratio of the produced electrical energy to the stored elastic energy in dentin under applied pressure. This study showed that the electromechanical coupling factor of dentin was affected by the direction of the applied force and the moisture content of dentin. Also dentin was a weak electromechanical energy converter which might be categorized as a piezoelectric pressure sensor.Evaluation of the hypothesis: Determination of the electrome-chanical coupling factor of dentin and its other piezoelectric constants is essential to investigate the biologic role of piezoelectricity in tooth.

  3. Characterization of Genipin-Modified Dentin Collagen

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    Hiroko Nagaoka

    2014-01-01

    Full Text Available Application of biomodification techniques to dentin can improve its biochemical and biomechanical properties. Several collagen cross-linking agents have been reported to strengthen the mechanical properties of dentin. However, the characteristics of collagen that has undergone agent-induced biomodification are not well understood. The objective of this study was to analyze the effects of a natural cross-linking agent, genipin (GE, on dentin discoloration, collagen stability, and changes in amino acid composition and lysyl oxidase mediated natural collagen cross-links. Dentin collagen obtained from extracted bovine teeth was treated with three different concentrations of GE (0.01%, 0.1%, and 0.5% for several treatment times (0–24 h. Changes in biochemical properties of NaB3H4-reduced collagen were characterized by amino acid and cross-link analyses. The treatment of dentin collagen with GE resulted in a concentration- and time-dependent pigmentation and stability against bacterial collagenase. The lysyl oxidase-mediated trivalent mature cross-link, pyridinoline, showed no difference among all groups while the major divalent immature cross-link, dehydro-dihydroxylysinonorleucine/its ketoamine in collagen treated with 0.5% GE for 24 h, significantly decreased compared to control (P< 0.05. The newly formed GE-induced cross-links most likely involve lysine and hydroxylysine residues of collagen in a concentration-dependent manner. Some of these cross-links appear to be reducible and stabilized with NaB3H4.

  4. New perspectives about molecular arrangement of primary and permanent dentin

    Energy Technology Data Exchange (ETDEWEB)

    Sanches Borges, Ana Flavia [Department of Dental Materials at Piracicaba Dental School, State University of Campinas, Piracicaba, SP (Brazil); Andrade Bitar, Renata [Biomedical Engineering, Valley of Paraiba University (UNIVAP) (Brazil); Kantovitz, Kamila Rosamilia [Department of Pediatric Dentistry at Piracicaba Dental School, State University of Campinas, Piracicaba, SP (Brazil); Bortollazo Correr, Americo [Department of Dental Materials at Piracicaba Dental School, State University of Campinas, Piracicaba, SP (Brazil); Martin, Airton Abrahao [Biomedical Engineering Post Graduation, Valley of Paraiba University (UNIVAP) (Brazil); Puppin-Rontani, Regina Maria [Department of Pediatric Dentistry at Piracicaba Dental School, State University of Campinas, Piracicaba, SP (Brazil)], E-mail: rmpuppin@fop.unicamp.br

    2007-12-30

    The dentin quality of primary and permanent teeth was inspected by Fourier transformed Raman spectroscopy (FT-Raman); scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS) and hardness test. Middle dentin of crowns were reached by carbide bur abrading providing a uniform smear layer. Phosphoric acid was applied in order to simulate the etching of total etching adhesive systems. The groups were (n = 10): G1 (primary dentin smear layer); G2 (35% phosphoric acid etched primary dentin); G3 (permanent dentin smear layer); G4 (35% phosphoric acid etched permanent dentin). FT-Raman results were subjected to cluster analysis. SEM/EDS were made in order to add the data obtained by FT-Raman. The hardness data were subjected to ANOVA and Tukey test. FT-Raman showed differences among groups, either to organic or inorganic content. For the organic content, primary and permanent dentin became similar after the etching; conversely, the inorganic content showed differences for the two substrates. Hardness test showed no significant differences between primary and permanent dentin, before or after etching, but the etching decreased these values. The mineral content arrangement of primary dentin is different from permanent dentin, independently of the etching. The substrate type did no influence the hardness, but the etching decreased it.

  5. New perspectives about molecular arrangement of primary and permanent dentin

    Science.gov (United States)

    Borges, Ana Flávia Sanches; Bitar, Renata Andrade; Kantovitz, Kamila Rosamilia; Correr, Américo Bortollazo; Martin, Airton Abrahão; Puppin-Rontani, Regina Maria

    2007-12-01

    The dentin quality of primary and permanent teeth was inspected by Fourier transformed Raman spectroscopy (FT-Raman); scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS) and hardness test. Middle dentin of crowns were reached by carbide bur abrading providing a uniform smear layer. Phosphoric acid was applied in order to simulate the etching of total etching adhesive systems. The groups were ( n = 10): G1 (primary dentin smear layer); G2 (35% phosphoric acid etched primary dentin); G3 (permanent dentin smear layer); G4 (35% phosphoric acid etched permanent dentin). FT-Raman results were subjected to cluster analysis. SEM/EDS were made in order to add the data obtained by FT-Raman. The hardness data were subjected to ANOVA and Tukey test. FT-Raman showed differences among groups, either to organic or inorganic content. For the organic content, primary and permanent dentin became similar after the etching; conversely, the inorganic content showed differences for the two substrates. Hardness test showed no significant differences between primary and permanent dentin, before or after etching, but the etching decreased these values. The mineral content arrangement of primary dentin is different from permanent dentin, independently of the etching. The substrate type did no influence the hardness, but the etching decreased it.

  6. Shear bond strength of amalgam to dentin using different dentin adhesive systems

    Directory of Open Access Journals (Sweden)

    Farimah Sardari

    2012-01-01

    Full Text Available Background and Aims: The aim of this in vitro study was to assess the shear bond strength of amalgam to dentin using four dentin adhesive systems.Materials and Methods: One hundred human molars were selected. After enamel removal, a dentin cylinder with 3 mm thickness was prepared. Eighty specimens were resorted with amalgam and four dentin adhesive systems as follows (n=20: group 1, Scotch Bond Multi-Purpose; group 2, One Coat Bond; group 3, PQ1; and group 4, Panavia-F. In group 5, 20 specimens were resorted with amalgam and varnish as control group. The specimens were incubated at 37°C for 24 h. The shear bond strengths were then measured by using push out method. The data were analyzed by one-way ANOVA and post hoc Duncan's tests.Results: Mean values for bond strengths of test groups were as follows: group 1=21.03±8.9, group 2=23.47±9, group 3=13.16±8.8, group 4=20.07±8.9 and group 5=14.15±8.7 MPa±SD. One-way ANOVA showed the statistically significant difference between the bond strengths of five groups (P=0.001. Post hoc Duncan's test showed significant difference between groups 1and 3 (P=0.008, groups 1 and 5 (P=0.019, groups 2 and 5 (P=0.0008, groups 4 and 5 (P=0.042, and groups 3 and 4 (P=0.018.Conclusion: Results of this study showed that the bond strength of amalgam to dentin using One Coat Bond as dentin adhesive system was higher than that observed in other dentin adhesive systems.

  7. Stickiness of dental resin composite materials to steel, dentin and bonded dentin.

    Science.gov (United States)

    Ertl, Kathrin; Graf, Alexandra; Watts, David; Schedle, Andreas

    2010-01-01

    Stickiness is a vital rheological parameter for the clinical handling behavior of unset resin composite restoratives. The aim of this study was to investigate the stickiness of three different resin composites at 23 degrees C and 37 degrees C tested on steel, dentin and dentin covered with different bonding agents. The stickiness instrument, used in this study consists of a vertical cylindrical stainless steel rod, with a flat circular end, and a platform with a cylindrical mold (diameter: 6.1mm, depth: 2.2mm). The test-material surface temperature and the speed of the rod can be modified. It moves slowly into the prepared mold which is filled with unset composite materials. The degree of stickiness is deducted from the height of the "elevation" the material forms when the plunger is withdrawn from the mold until the steelhead detaches itself from the composite. In this study, stickiness was tested directly to the steel plunger and to dentin slices (uncovered or covered with two different bonding agents) fixed to the plunger rod with a clamp. The coefficients of variation (CVs) were generally less than 0.10, indicating that the stickiness instrument offers an adequately reproducible way of testing stickiness. The tested composite materials varied significantly in stickiness. For all investigated materials a decrease of peak heights with increasing speed was found (for all three materials: pcomposites was higher on dentin than on steel and least on bonded dentin. The order of stickiness of composites was not affected by testing the stickiness on the different materials. This method allows the characterization of composite resin materials stickiness to steel, as equivalent to dental steel instruments, and to bonded dentin as equivalent to the tooth cavity after preparation. An ideal material should have a sufficient difference between stickiness on steel and dentin so that it remains in the cavity and is not pulled back by the steel instrument.

  8. accidentes y otras causas violentas en la sierra de Sonora

    Directory of Open Access Journals (Sweden)

    Héctor Eloy Rivas Sánchez

    2005-01-01

    Full Text Available Este artículo presenta los resultados de una investigación sociológica cuyo objeto fue explorar el papel que ha jugado el modelo hegemónico de masculinidad en la ocurrencia de muertes derivadas de accidentes y varias formas de ejercicio de la violencia en una comunidad rural de la sierra de Sonora. Estos resultados difieren de aquellos que tradicionalmente los estudios de las masculinidades han mostrado para México y América Latina. El modelo dominante de masculinidad en las comunidades estudiadas no ha condicionado significativamente la ocurrencia de las muertes por accidentes y otras causas violentas. La responsabilidad, la disciplina y el respeto hacia las personas consideradas socialmente débiles (mujeres, ancianos y niños, principalmente son características que debe poseer un hombre de verdad en las comunidades estudiadas. El apego de los hombres a estas formas de comportamiento y su temor a perder honorabilidad como hombre de verdad si se desvían de estas normas de conducta los ha llevado a evitar una serie de prácticas temerarias que pudieron poner en riesgo su vida y la de otras personas.

  9. Movimientos migratorios y curso de vida: causas y patrones especiales

    Directory of Open Access Journals (Sweden)

    Puga González, Dolores

    2002-12-01

    Full Text Available This is a longitudinal analysis of the mobility causes and patterns of the Spanish generations bom before 1936. Almost half of the residential changes didn't go beyond the province border, generally bound to family reasons (marriage. In the first years of life, the individuals move engaged in the mobility of their parents. In the teen-ages social (studies and other and economic (first employment, etc. reasons add to them. Around the 25 years old the economic and family reasons highlight.

    Estudio de las causas y patrones de la movilidad de las generaciones españolas nacidas antes de 1936, aplicando un análisis longitudinal. Casi la mitad de los cambios residenciales no traspasaron la frontera provincial, generalmente ligados a motivos familiares (matrimonio. En los primeros años de vida, los individuos se mueven «arrastrados» por la movilidad de sus padres; en la adolescencia, se suman razones sociales (estudios y otras y económicas (primer empleo, etc.; en tomo a los 25 años destacan los motivos económicos y familiares.

  10. Darwin, Hume, Morgan, and the verae causae of psychology.

    Science.gov (United States)

    Clatterbuck, Hayley

    2016-12-01

    Charles Darwin and C. Lloyd Morgan forward two influential principles of cognitive ethological inference that yield conflicting results about the extent of continuity in the cognitive traits of humans and other animals. While these principles have been interpreted as reflecting commitments to different senses of parsimony, in fact, both principles result from the same vera causa inferential strategy, according to which "We ought to admit no more causes of natural things, than such as are both true and sufficient to explain their appearances". Instead, the conflict stems from Darwin's and Morgan's views about the true causes of human psychology. Darwin holds a thoroughly Humean philosophy of the human mind, from which he infers significant continuity between human and animal minds. In contrast, Morgan argues that Humean cognitive mechanisms cannot account for a class of uniquely human behaviors, and therefore, he concludes that there is a significant discontinuity between human and animal cognition. This historical debate is informative for current controversies in comparative psychology. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Causas y consecuencias de la deficiencia de hierro

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    Olivares Manuel

    2004-01-01

    Full Text Available La deficiencia de hierro es la deficiencia nutricional más prevalente y la principal causa de anemia a escala mundial. Además de las manifestaciones propias de la anemia, se han descrito otras manifestaciones no hematológicas tales como: disminución de la capacidad de trabajo físico y de la actividad motora espontánea, alteraciones de la inmunidad celular y de la capacidad bactericida de los neutrófilos, disminución de la termogénesis, alteraciones funcionales e histológicas del tubo digestivo, falla en la movilización de la vitamina A hepática, mayor riesgo de parto prematuro, bajo peso de nacimiento y de morbilidad perinatal, menor transferencia de hierro al feto, una disminución de la velocidad de crecimiento, alteraciones conductuales y del desarrollo mental y motor, velocidad de conducción más lenta de los sistemas sensoriales auditivo y visual, y reducción del tono vagal. La prevención de la deficiencia de hierro incluye cambios en los hábitos alimentarios, fortificación de los alimentos y la suplementación con hierro.

  12. Boca seca: causas, diagnóstico y tratamiento

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    Tomás de la Paz Suárez

    2014-10-01

    Full Text Available Definida como la sensación subjetiva de disminución o ausencia de la secreción salival, la boca seca o xerostomía tiene origen multicausal y comprende tanto enfermedades crónicas, como la diabetes mellitus, el uso de medicamentos como los antihipertensivos, quimioterápicos, los pacientes que padecen de cáncer y son sometidos a radiaciones. Se realizó una revisión bibliográfica, con el objetivo de actualizar conocimientos sobre sus causas, diagnóstico y tratamiento, utilizando los recursos disponibles en la red Infomed. Se consultaron diferentes bases de datos especializadas como: Medline, Mediclatina, PubMed, Hinari y Scielo. El síndrome de boca seca requiere de un diagnóstico integral, teniendo en cuenta el interrogatorio, el examen bucal y pruebas complementarias; la correcta salud bucodental es la base fundamental para su prevención y tratamiento

  13. Poro dérmico. Causa de meningoencefalitis reiterativa

    Directory of Open Access Journals (Sweden)

    Aimara Castillo Escriba

    2015-12-01

    Full Text Available En el Hospital Pediátrico Provincial “Mártires de las Tunas” se atendió paciente de 13 meses de edad, con antecedentes patológicos personales de salud, que ingresó a la sala de terapia intensiva por presentar una Meningoencefalitis bacteriana, donde se aisló un bacilo no fermentador. Al examen físico se corroboró la presencia de un poro dérmico en la región sacra, rodeado de una zona hiperpigmentada. Ante el diagnóstico se impone el tratamiento y el paciente responde favorablemente. A los cinco meses ingresó nuevamente con igual cuadro, y alrededor del poro dérmico presentaba una pequeña costra, por lo que se indicó una resonancia magnética, la cual arrojo que las meningoencefalitis habían sido producto a la entrada de gérmenes a través del poro dérmico, que, a su vez, llegaba a un quiste dermoide érmicoquídeo y extramedular. Se sugirió una intervención quirúrgica, la cual solucionó la causa primaria de las meningoencefalitis en este paciente.

  14. La angustia por la causa // The angst by the cause

    Directory of Open Access Journals (Sweden)

    Juan Manuel Uribe

    2011-12-01

    Full Text Available El artículo pretende mostrar cómo en todo acto de fundación se sucede una pérdida, un resto que se pretende olvidar desde los múltiples discursos humanos, incluido el científico; empero, eso que resta y que se pretende olvidar es precisamente lo que retorna para descompletar, para desajustar la imaginaria completitud del ser de deseantes. Dicho retorno y la operación de resta, de des-completitud, es lo que genera la angustia, connatural al registro de lo simbólico. Para comprender este sentimiento y el movimiento de la fundación humana, Lacan crea en su algebra el "a", operador de la causa y objeto mismo que se mueve en el registro de lo real. // The present work tries to show how after every foundation act a loss appears, a memory that they pretend to forget from various human speeches, including scientific discourse; nevertheless, this that continue and is expected to be forgot is exactly what return to make incomplete, to disarrange the completeness imaginary of the desire person. Mentioned return and subtraction operation, of un-completeness, is the generator factor of angst, inherent to the symbolic record. Understanding this feeling and the movement of the human foundation, Lacan creates the "a" in his algebra, cause operator and object by itself that moves inside the real record.

  15. The connective por causa que: grammaticalization and analysis of grammatical and semantic-discursive properties

    Directory of Open Access Journals (Sweden)

    Fabrício da Silva Amorim

    2013-02-01

    Full Text Available This article aims to characterize the Portuguese locution "por causa que"(“because that”, from theoretical-methodological proposals based on the functional paradigm of Grammaticalization. Firstly, hypotheses on "por causa que"appearance and an analysis of its status of conjunction are presented. Furthermore, the usage patterns of "por causa que" in spoken Portuguese are investigated using a semantic-cognitive approach (SWEETSER, 1991; TRAUGOTT; KÖNIG, 1991. The following analyses take into consideration not only the "por causa que"clause, but the whole clausal complex in which the conjunctive phrase is inserted – causal segment and effect segment –, aiming at presenting a specially discursive description of these constructions. Most of the results show many convergences between the constructions with "por causa que"and "porque"(because, which is considered to be the prototypical causal connector.

  16. Frameshift mutations in dentin phosphoprotein and dependence of dentin disease phenotype on mutation location.

    Science.gov (United States)

    Nieminen, Pekka; Papagiannoulis-Lascarides, Lisa; Waltimo-Siren, Janna; Ollila, Päivi; Karjalainen, Sara; Arte, Sirpa; Veerkamp, Jaap; Tallon Walton, Victoria; Chimenos Küstner, Eduard; Siltanen, Tarja; Holappa, Heidi; Lukinmaa, Pirjo-Liisa; Alaluusua, Satu

    2011-04-01

    We describe results from a mutational analysis of the region of the dentin sialophosphoprotein (DSPP) gene encoding dentin phosphoprotein (DPP) in 12 families with dominantly inherited dentin diseases. In eight families (five mutations in the N-terminal third of DPP), the clinical and radiologic features were uniform and compatible with dentin dysplasia type II (DD-II) with major clinical signs in the deciduous dentition. In the other families (four mutations in the more C-terminal part), the permanent teeth also were affected, and the diseases could be classified as variants of dentinogenesis imperfecta. Attrition was not prominent, but periapical infections were common. Discoloring with varying intensity was evident, and pulps and root canals were obliterated in the permanent dentition. All mutations caused a frameshift that replaced the Ser-Ser-Asx repeat by a code for a hydrophobic downstream sequence of approximately original length. We conclude that frameshift mutations in DSPP explain a significant part of dentin diseases. Furthermore, we propose that the location of the mutation is reflected in the phenotypic features as a gradient from DD-II to more severe disease that does not conform to the classic definitions of DI-II. Copyright © 2011 American Society for Bone and Mineral Research.

  17. Localization of phosphophoryn in rat incisor dentin using immunocytochemical techniques.

    Science.gov (United States)

    Rahima, M; Tsay, T G; Andujar, M; Veis, A

    1988-02-01

    We studied the distribution of the phosphophoryn present in rat incisors by immunolocalization and histochemical techniques. The polyclonal antibody used reacts with both phosphorylated and de-phosphorylated phosphophoryn. Technical problems encountered in immunostaining and in preparing sections from mineralized dentin were resolved by use of peroxidase-conjugated protein A as the "second antibody" in indirect immunostaining reactions and by surface etching of partially demineralized sections. Staining with anti-rat incisor alpha-phosphophoryn antibody showed light staining over the odontoblasts and proximal odontoblastic processes, no stain over the predentin, dense staining over the intertubular dentin, and no stain over the mantle dentin. In the intertubular dentin the stain intensity was directly related to the distribution of mineral. These findings were directly corroborated by staining with Stains All. The mineralization of dentin and the distribution of phosphophoryn within the dentin may be much less uniform than previously supposed.

  18. Changes in matrix phosphorylation during bovine dentin development.

    Science.gov (United States)

    Verdelis, Kostas; Lukashova, Lyudmilla; Yamauchi, Mitsuo; Atsawasuwan, Peter; Wright, John T; Peterson, Margaret G E; Jha, Divya; Boskey, Adele L

    2007-08-01

    Phosphorylation of the organic matrix proteins of dentin is important for the initiation of mineralization, but its relevance in later mineralization stages is controversial. The objective of this study was to analyze changes in the total matrix phosphate content during dentin development and to identify their origin. Amino acid and total matrix phosphate analyses of microdissected developing mantle and circumpulpal fetal bovine dentin specimens were performed. The amino acid composition showed few changes during mantle and circumpulpal dentin maturation. However, the total matrix phosphate content showed a significant, positive correlation with tissue maturation in both mantle and circumpulpal dentin, with a two- and a three-fold increase, respectively, being observed. The data indicate that changes occur in the pattern of phosphorylation of matrix proteins during dentin maturation, which we suggest may play a functional role in later stages of tooth mineralization.

  19. Relation between incremental lines and tensile strength of coronal dentin.

    Science.gov (United States)

    Inoue, Toshiko; Saito, Makoto; Yamamoto, Masato; Nishimura, Fumio; Miyazaki, Takashi

    2012-01-01

    In one aspect, this study examined the tensile strength of coronal dentin, as a function of the location of incremental lines, in two types of teeth: human molar versus bovine incisor. In another aspect, tensile strength in coronal dentin was examined with tensile loading in two different orientations to the incremental lines: parallel versus perpendicular. There were four experimental groups in this study: HPa, human molar dentin with tensile orientation parallel to the incremental lines; HPe, human molar dentin with tensile orientation perpendicular to the incremental lines; BPa, bovine incisor dentin with tensile orientation parallel to the incremental lines; BPe, bovine incisor dentin with tensile orientation perpendicular to the incremental lines. Tensile strengths of the parallel group (HPa and BPa) were significantly higher (pdentin. However, there were no differences in anisotropy effect between the two tooth types.

  20. Bond strength versus dentine structure: a modelling approach.

    Science.gov (United States)

    Pashley, D H; Ciucchi, B; Sano, H; Carvalho, R M; Russell, C M

    1995-12-01

    Bond strengths of a hypothetical hydrophilic dentine-bonding agent were calculated as a function of dentine depth and resin strength to evaluate the importance of several variables in a simple model. The tested hypothesis was that the total bond strength was the sum of the strengths of resin tags, hybrid layer and surface adhesion. Each of these three variables has a range of values that can influence its relative contribution. The resulting calculations indicate the potential for higher bond strengths to deep dentine than to superficial dentine in non-vital dentine and the importance of resin strength in the development of strong bonds. Comparison of the calculated bonds with published values indicated that they were within the same order of magnitude. Such theoretical modelling of dentine bonding can identify the relative importance of variables involved in the substrate, resins and surface adhesion.

  1. Regeneratieve capaciteit van de pulpa: adulte humane stamcellen uit de pulpa: meer dan reparatie van dentine

    NARCIS (Netherlands)

    Bronckers, A.L.J.J.

    2010-01-01

    Vorming van tertiair dentine is de natuurlijke reactie van de pulpa om zich te beschermen na verwonding. Reactief dentine wordt geproduceerd door de oorspronkelijke (primaire) odontoblasten die tijdelijk geactiveerd worden. Reparatief dentine wordt gevormd vanuit secundaire odontoblasten, ontstaan

  2. Dentine tubule infection and endodontic therapy implications.

    Science.gov (United States)

    Oguntebi, B R

    1994-07-01

    A critical review of the literature suggests that the microenvironment of dentinal tubules appears to favour the selection of relatively few bacterial types irrespective of the aetiology of the infection process; coronal dental caries or pulpar necrosis. These bacteria may constitute an important reservoir from which root canal infection and reinfection may occur following pulp necrosis or during and after endodontic treatment. Previous studies of this microflora have utilized microbiological culture techniques which need to be supplemented by those that allow in situ demonstration as well as identification of the bacteria. Newer treatment strategies that are designed to eliminate this microflora must include agents that can penetrate the dentinal tubules and destroy these microorganisms, since they are located in an area beyond the host defence mechanisms where they cannot be reached by systemically administered antimicrobial agents.

  3. Bahan-Bahan Pembentuk Dentin Sekunder Dalam Bidang Kedokteran Gigi

    OpenAIRE

    Ahmad Fauzi M.

    2008-01-01

    Sepanjang hidup, selama pulpa masih vital, dentin sekunder terbentuk secara teratur pada tepi pulpa, hal ini merupakan fungsi formatif pulpa yaitu jaringan pulpa mampu mengadakan reparasi dalam menanggulangi cedera yang diterima. Dentin sekunder yang dibentuk berfungsi dalam hal pertahanan diri terhadap efek atrisi, karies gigi, trauma, dan mengurangi masuknya iritan. Bahan-bahan pembentuk dentin sekunder dapat digunakan pada keadaan dimana jaringan pulpa tidak mampu lagi mengadakan repa...

  4. Morphological effects of MMPs inhibitors on the dentin bonding

    OpenAIRE

    Li, He; Li, Tianbo; Li, Xiuying; Zhang, Zhimin; Li, Penglian; Li, Zhenling

    2015-01-01

    Matrix metalloproteinases (MMPs) have been studied extensively, and MMP inhibitors have been used as dental pretreatment agents prior to dentin bonding because they reduce collagen fiber degradation and improve bonding strength. However, morphologic characteristics of the collagen network after etching and of the post-adhesive dentin hybrid layers (DHL) after MMP inhibitors pretreatment have not been evaluated. Thus, we investigated demineralized dentin pretreated with chlorhexidine (CHX) and...

  5. Evaluation of the Shear Bond Strength of Nanocomposite on Carious and Sound Deciduous Dentin

    OpenAIRE

    Deshmukh, Seema; Nandlal, B.

    2012-01-01

    ABSTRACT Aim: The aim of the study was to evaluate and compare the shear bond strength of conventional composites with nanocomposites in carious and sound deciduous dentin with the use of self-etching adhesive. Methodology: Human primary molars were ground to obtain flat dentin surfaces and divided into two groups: Carious dentin and sound dentin group. The carious teeth specimens were prepared by removing infected dentin and area with affected dentin was used for bonding composite. Teeth wit...

  6. DSPP Contains an IRES Element Responsible for the Translation of Dentin Phosphophoryn

    OpenAIRE

    Zhang, Y.; Song, Y.; Ravindran, S.; Gao, Q; Huang, C. C.; Ramachandran, A.; Kulkarni, A; George, A.

    2014-01-01

    The major phosphoprotein in dentin is the aspartic acid and serine-rich protein called dentin phosphophoryn (DPP). DPP appears to be synthesized as a part of a larger compound protein, dentin sialophosphoprotein (DSPP). DSPP has never been isolated or detected in dentin extracts. It is now evident that DSPP is a chimeric protein composed of 3 parts: dentin sialoprotein (DSP), DPP, and dentin glycoprotein (DGP). Previous reports have suggested that the BMP1 protease is responsible for processi...

  7. Phenotypic heterogeneity of Streptococcus mutans in dentin.

    Science.gov (United States)

    Rupf, S; Hannig, M; Breitung, K; Schellenberger, W; Eschrich, K; Remmerbach, T; Kneist, S

    2008-12-01

    Information concerning phenotypic heterogeneity of Streptococcus mutans in carious dentin is sparse. Matrix-assisted laser-desorption/ionization-time-of-flight mass-spectrometry (MALDI-TOF-MS) facilitates the phenotypic differentiation of bacteria to the subspecies level. To verify a supposed influence of restorative treatment on the phenotypic heterogeneity of S. mutans, we isolated and compared a total of 222 S. mutans strains from dentin samples of 21 human deciduous molars during caries excavation (T(1)) and 8 wks (T(2)) after removal of the temporary restoration. Phenotypic heterogeneity was determined by MALDI-TOF-MS and hierarchical clustering. Thirty-six distinct S. mutans phenotypes could be identified. Although indistinguishable phenotypes were found in the same teeth at T(1) and T(2), as well as in different teeth of individual participants, the phenotypic heterogeneity increased significantly, from 1.4 phenotypes per S. mutans-positive dentin sample at T(1) to 2.2 phenotypes at T(2). We attribute this to an adaptation of S. mutans to the modified environment under the restoration following caries excavation.

  8. Chemical treatment of the intra-canal dentin surface: a new approach to modify dentin hydrophobicity

    Directory of Open Access Journals (Sweden)

    Cesar GAITAN-FONSECA

    2013-01-01

    Full Text Available Objective This study evaluated the hydrophobicity of dentin surfaces that were modified through chemical silanization with octadecyltrichlorosilane (OTS. Material and Methods An in vitro experimental study was performed using 40 human permanent incisors that were divided into the following two groups: non-silanized and silanized. The specimens were pretreated and chemically modified with OTS. After the chemical modification, the dentin hydrophobicity was examined using a water contact angle measurement (WCA. The effectiveness of the modification of hydrophobicity was verified by the fluid permeability test (FPT. Results and Conclusions Statistically significant differences were found in the values of WCA and FPT between the two groups. After silanization, the hydrophobic intraradicular dentin surface exhibited in vitro properties that limit fluid penetration into the sealed root canal. This chemical treatment is a new approach for improving the sealing of the root canal system.

  9. SEM study on the dentin and cementum of oreodont teeth.

    Science.gov (United States)

    Higashi, Y; Iwai-Liao, Y; Tada, I; Okumura, A; Fujita, K; Takagi, M

    1989-04-01

    An SEM study on the dental hard tissue was conducted on the canines and molars removed from a fossil oreodont. The orthodentin was densely distributed with dentinal tubules measuring 2.2 microns in diameter; the tubules were filled with their related odontoblastic processes. They coursed in a parabolic fashion from the pulpal aspect towards the tooth surface. There were many fine lateral offshoots that branched from the tubules, such that the mantle dentin measuring 50 microns in thickness was mostly distributed with these terminal branches measuring 0.7 micron in diameter. However, they did not intrude into the enamel to form spindles and rods. SEM study indicated that the uneven surface of the tubular wall was due to a crisscross of the underneath dentinal matricial fibers, and the peritubular dentin was not observed. The superficial circumpulpal dentin was distributed with interglobular dentin, while the radicular dentin beneath the cementum was additionally distributed with a granular layer. We also observed concentric lamellae corresponding to incremental lines in the dentin, as well as a flat wavy dentinoenamel junction. We noticed the radicular dentin was covered with an acellular cementum except at the apical portion, where it was paved with cellular cementum.

  10. Mantle dentine in man--a quantitative microradiographic study.

    Science.gov (United States)

    Herr, P; Holz, J; Baume, L J

    1986-06-01

    50 microradiographs taken in a standardized manner of midsagittal ground sections of teeth of individuals aged 18 to 56 years were densitometrically evaluated along a track passing through enamel, dentine and an aluminium stepwedge. Semi-quantitative analysis of mineral density uniformly showed an irregular platform representing circumpulpal dentine and a peripheral down slope in the region of the amelodentinal junction, representing mantle dentine. The width of this less mineralized peripheral zone measured on densitometric recordings averaged 150 microns (+/- 50). Quantitative analysis of the two dentinal regions permitted the calculation of the mineral content in terms of volume percentage using both a graphic method and an electronic computer method. The sections were also examined by polarized light microscopy which clearly visualized the presence of peripheral mantle dentine. The mean mineral density of circumpulpal dentine was 46% according to both the graphic and the computer methods; mantle dentine yielded means close to 42% according by both methods. The 4% difference in density between circumpulpal dentine and mantle dentine proved to be statistically significant; there was no significant difference between the means obtained graphically and those obtained electronically. The need for further investigation of this region of the amelodentinal junction was stressed.

  11. [The effect of bleaching on fracture resistance in human dentin].

    Science.gov (United States)

    Xu, Yuanzhi; Wang, Raorao; An, Bingbing; Zhou, Yinxiao; Yu, Haiyang; Zhang, Dongsheng

    2012-10-01

    To study the effect of bleaching on the mechanical properties of human dentin. The finite element method (FEM) based the cohesive zone model had been employed to study the fracture resistance of human dentin. There types of dentin were considered, i.e. original dentin, dentin after direct-bleaching and indirect-bleaching. The bleaching treatments had large impact on the crack growth resistance of human dentin. The initiation toughness (1.48 MPa x square root of m), growth toughness (3.90 MPa x square root of m x mm(-1)) and plateau toughness (3.25 MPa x square root of m) of human dentin were reduced to 1.29 MPa x square root of m, 3.45 MPa x square root of m x mm(-1) and 2.71 MPa x square root of m respectively after indirect-bleaching. The worst case was the direct-bleaching which causes significant reductions in the growth toughness (0.14 MPa x square root of m x mm(-1)) and plateau toughness (1.63 MPa x square root of m) respectively, while the initiation toughness remained the same as that after indirect-bleaching. The cohesive zone modeling is an effective tool in characterizing the fracture behavior of human dentin. Bleaching treatments reduce the crack growth resistance of human dentin and increase the risk of fracture of teeth.

  12. Why do shear bond tests pull out dentin?

    Science.gov (United States)

    Versluis, A; Tantbirojn, D; Douglas, W H

    1997-06-01

    It is widely accepted that a dentin shear bond test which pulls out dentin must mean that the adhesive strength is superior to the cohesive strength of the dentin. Using numerical modeling techniques, Van Noort et al. (1988, 1989) and DeHoff et al. (1995) alerted the scientific community that there were massive stress concentrations in the familiar dentin bond test. It is not inconceivable that these localized high tensile stresses could initiate cracks which diverge monolithically into dentin, leaving the interface unchallenged. To test this hypothesis, we developed a failure accumulation simulation program which determined localized failure interactively "on the fly" with a finite element solver, and also included brittle behavior, adhesive and cohesive failure, stochastic response, and dynamic remeshing. All of the familiar dentin bond variables were included in the simulation. A parallel experimental dentin bond test validation was run, and the fractography was examined in the scanning electron microscope for mode of failure. The simulation confirmed the tensile monolithic fracture hypothesis. It is also confirmed that dentin pull-out was partly due to the biomechanics of the test and did not necessarily mean superior adhesive strength or even that the cohesive strength of the dentin was reduced. There is clear need for a new technology for the evaluation of biological interfaces, and the present work has shown the vital role of numerical modeling in the interpretation of such experimental procedures.

  13. Compositional design and optimization of dentin adhesive with neutralization capability

    National Research Council Canada - National Science Library

    Song, Linyong; Ye, Qiang; Ge, Xueping; Spencer, Paulette

    2015-01-01

    The objective of this work was to investigate the polymerization behavior, neutralization capability, and mechanical properties of dentin adhesive formulations with the addition of the tertiary amine...

  14. Scanning electron microscopy of pulp cavity dentin in dogs.

    Science.gov (United States)

    Hernández, Sabás Z; Negro, Viviana B; Paulero, Rodrigo H; Toriggia, Paula G; Saccomanno, Daniela M

    2010-01-01

    Dentin morphology and tubule diameter and density of peripulpal dentin were evaluated in 36 teeth from 12 adult dogs, aged between 2.5 and 13-years. The right maxillary canine and third premolar and right mandibular first molar teeth were extracted from euthanized dogs. The teeth were prepared and photomicrographs (n=108) were taken of the radicular and coronal dentin. Dentinal tubule density (tubules/mm2) was determined and tubular diameter and luminal area were measured in 3240 randomly chosen tubules using measurement software. Results from group 1 dogs (dogs (> 7-years-old). The majority of dentinal tubules were round or oval in shape and had uniform distribution at the radicular coronal third, and coronal levels. Dentin surfaces showed morphological differences at different levels of the tooth. Group 1 dentinal tubule diameter (1.87 +/- 0.44 microm) and area (1.91 +/- 0.83 microm2) were significantly different compared with Group 2 dentinal tubule diameter (1.53 +/- 0.39 microm) and area (1.22 +/- 0.50 microm2). There was no significant difference in tubular density between groups 1 (74,692 +/- 25,991 tubules/mm2) and 2 (72,938 +/- 24,646 tubules/mm2). Site-specific differences were observed in the pulp cavity dentin in the same tooth. These results provide a reference for future research in dogs or where dogs are used as a model for investigations in human dentistry.

  15. Two-year composite/dentin bond stability.

    Science.gov (United States)

    Meiers, J C; Young, D

    2001-06-01

    To examine the composite-to-dentin shear bond strengths over 2 yrs of three chemically different single bottle dentin adhesives: water-based Syntac Single Component (SSC); acetone-based Prime & Bond 2.1 (PB), and; ethanol-based and filled OptiBond Solo (OS). Extracted human molars stored in 0.2% sodium azide were randomly assigned to each of three dentin bond groups for testing at 5 time periods (n=15). The crowns of the teeth were sectioned to expose occlusal dentin and the roots embedded in acrylic. The dentin was etched with 37% H3PO4 for 20 s, rinsed and dentin adhesives applied per manufacturers' instructions. A column of Z-100 composite was bonded to the treated dentin surface and light cured. Teeth were stored in distilled water at 37 degrees C and thermocycled for 1,000 cycles between 5 degrees C and 55 degrees C and tested in shear at 24 hrs (baseline), 6, 12, 18 and 24 months. Mean +/- SD shear bond strengths (SBS) were determined. ANOVA at a significance level of Pstability of resin-based composite to dentin bond strengths from single bond adhesives is questionable because after 2 yrs, bond strengths for two of the three tested dentin adhesives, OptiBond Solo and Syntac Single Component, were significantly lower than initial strengths.

  16. Photosensitizer and light diffusion through dentin in photodynamic therapy

    Science.gov (United States)

    Nogueira, Ana C.; Graciano, Ariane X.; Nagata, Juliana Y.; Fujimaki, Mitsue; Terada, Raquel S. S.; Bento, Antonio C.; Astrath, Nelson G. C.; Baesso, Mauro L.

    2013-05-01

    Photodynamic therapy has been considered a potential antimicrobial modality against oral infections, including dental caries. A model to estimate the penetration of both photosensitizers and light through human dentin, a factor of interest in photodynamic therapy, is proposed. The photoacoustic spectroscopy technique was used to evaluate in vitro dentin permeability of three different photosensitizers. Using the dentin optical absorption and scattering coefficients, it was possible to propose a semi-quantitative model predicting both photosensitizer and light doses within dentin. The graphic illustrations obtained provided guidelines that may be useful in photodynamic therapy protocols used as antimicrobial tools in caries lesions.

  17. Efficacy of Modified Bioactive Glass for Dentin Remineralization and Obstruction of Dentinal Tubules

    Directory of Open Access Journals (Sweden)

    Mahshid Saffarpour

    2017-10-01

    Full Text Available Objectives: This study assessed the efficacy of modified bioactive glass (MBG for dentin remineralization and obstruction of dentinal tubules.Materials and Methods: Thirty-six dentin discs were made from 20 third molars and were stored in 12% lactic acid solution for two weeks to induce demineralization. The samples were divided into three groups (n=12: 1- BG, 2- BG modified with 5% strontium (Sr and 3- BG modified with 10% Sr. After applying the BG, the samples were stored in artificial saliva for 7, 14 and 21 days. Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR, X-ray Diffraction (XRD analysis, Scanning Electron Microscopy (SEM, and Energy-Dispersive X-ray (EDX analysis were used to assess remineralization. Also, 6 dentin discs were divided into three groups of BG, BG modified with 5% Sr and BG modified with 10% Sr, to examine tubular occlusion. The discs were etched using 0.5M of EDTA for two minutes and were stored in artificial saliva for 7 days. Changes in dentin surface morphology were evaluated under SEM.Results: Group 3 showed high rates of remineralization at days 7 and 14, although the rate decreased at day 21. Group 2 exhibited high rates of remineralization at days 7, 14 and 21. Dentinal tubules were partially occluded by BG and BG modified with 5% Sr, while they were almost completely obstructed after the use of BG modified with 10% Sr.Conclusions: Strontium increases remineralization. Addition of 10% Sr to BG enhances apatite formation; however, the apatite dissolves over time. Addition of 5% Sr to BG stabilizes the apatite lattice and increases the remineralization.

  18. Identification of full-length dentin matrix protein 1 in dentin and bone.

    Science.gov (United States)

    Huang, Bingzhen; Maciejewska, Izabela; Sun, Yao; Peng, Tao; Qin, Disheng; Lu, Yongbo; Bonewald, Lynda; Butler, William T; Feng, Jian; Qin, Chunlin

    2008-05-01

    Dentin matrix protein 1 (DMP1) has been identified in the extracellular matrix (ECM) of dentin and bone as the processed NH(2)-terminal and COOH-terminal fragment. However, the full-length form of DMP1 has not been identified in these tissues. The focus of this investigation was to search for the intact full-length DMP1 in dentin and bone. We used two types of anti-DMP1 antibodies to identify DMP1: one type specifically recognizes the NH(2)-terminal region and the other type is only reactive to the COOH-terminal region of the DMP1 amino acid sequence. An approximately 105-kDa protein, extracted from the ECM of rat dentin and bone, was recognized by both types of antibodies; and the migration rate of this protein was identical to the recombinant mouse full-length DMP1 made in eukaryotic cells. We concluded that this approximately 105-kDa protein is the full-length form of DMP1, which is considerably less abundant than its processed fragments in the ECM of dentin and bone. We also detected the full-length form of DMP1 and its processed fragments in the extract of dental pulp/odontoblast complex dissected from rat teeth. In addition, immunofluorescence analysis showed that in MC3T3-E1 cells the NH(2)-terminal and COOH-terminal fragments of DMP1 are distributed differently. Our findings indicate that the majority of DMP1 must be cleaved within the cells that synthesize it and that minor amounts of uncleaved DMP1 molecules are secreted into the ECM of dentin and bone.

  19. A Mechanistic study of Plasma Treatment Effects on Demineralized Dentin Surfaces for Improved Adhesive/Dentin Interface Bonding

    Science.gov (United States)

    Dong, Xiaoqing; Chen, Meng; Wang, Yong; Yu, Qingsong

    2014-01-01

    Our previous work has shown that non-thermal plasma treatment of demineralized dentin significantly (p<0.05) improved adhesive/dentin bonding strength for dental composite restoration as compared with the untreated controls. This study is to achieve mechanistic understanding of the plasma treatment effects on dentin surface through investigating the plasma treated dentin surfaces and their interaction with adhesive monomer, 2-Hydroxyethyl methacrylate (HEMA). The plasma treated dentin surfaces from human third molars were evaluated by water contact angle measurements and scanning electron microscopy (SEM). It was found that plasma-treated dentin surface with subsequent HEMA immersion (Plasma/HEMA Treated) had much lower water contact angle compared with only plasma-treated (Plasma Treated) or only HEMA immersed (HEMA Treated) dentin surfaces. With prolong water droplet deposition time, water droplets spread out completely on the Plasma/HEMA Treated dentin surfaces. SEM images of Plasma/HEMA Treated dentin surfaces verified that dentin tubules were opened-up and filled with HEMA monomers. Extracted type I collagen fibrils, which was used as simulation of the exposed dentinal collagen fibrils after acid etching step, were plasma treated and analyzed with Fourier transform infrared spectroscopy (FT-IR) and circular dichroism (CD) spectra. FT-IR spectra of the Plasma/HEMA Treated collage fibrils showed broadened amide I peak at 1660 cm−1 and amide II at 1550 cm−1, which indicate secondary structure changes of the collagen fibrils. CD spectra indicated that 67.4% collagen helix structures were denatured after plasma treatment. These experimental results demonstrate that non-thermal argon plasma treatment was very effective in loosing collagen structure and enhancing adhesive monomer penetration, which are beneficial to thicker hybrid layer and longer resin tag formation, and consequently enhance adhesive/dentin interface bonding. PMID:25267936

  20. Dentin matrix protein 1 and dentin sialophosphoprotein in human sound and carious teeth: an immunohistochemical and colorimetric assay

    Directory of Open Access Journals (Sweden)

    D. Martini

    2013-10-01

    Full Text Available Dentin matrix protein 1 (DMP1 and dentin sialophosphoprotein (DSPP are extracellular matrix proteins produced by odontoblasts involved in the dentin mineralization. The aim this study was to compare the distribution of DMP1 and DSPP in human sound dentin vs human sclerotic dentin. Sixteen sound and sixteen carious human molars were selected, fixed in paraformaldehyde and processed for immunohistochemical detection of DMP1 and DSPP by means of light microscopy, transmission electron microscopy (TEM and high-resolution field emission in-lens scanning electron microscopy (FEI-SEM. Specimens were submitted to a pre-embedding or a post-embedding immunolabeling technique using primary antibodies anti DMP1 and anti-DSPP and gold-conjugated secondary antibodies. Other samples were processed for the detection of DMP1 and DSPP levels. Dentin from these samples was mechanically fractured to powder, then a protein extraction and a protein level detection assay were performed. DMP1 and DSPP were more abundant in carious than in sound samples. Immunohistochemical analyses in sclerotic dentin disclosed a high expression of DMP1 and DSPP inside the tubules, suggesting an active biomineralization of dentin by odontoblasts. Furthermore, the detection of small amounts of these proteins inside the tubules far from the carious lesion, as shown in the present study, is consistent with the hypothesis of a preventive defense of all dentin after a noxious stimulus has undermined the tooth.

  1. Strontium effects on root dentin tubule occlusion and nanomechanical properties.

    Science.gov (United States)

    Saeki, Kuniko; Marshall, Grayson W; Gansky, Stuart A; Parkinson, Charles R; Marshall, Sally J

    2016-02-01

    Dentin hypersensitivity often is treated by promotion of dentin tubule occlusion. In this in vitro study we evaluated nanomechanical properties and degree of tubule occlusion conferred to sound and demineralized human root dentin following treatment with a 10% (w/w) strontium acetate solution and its relation to the treatment duration and delivery method. 24 human cervical root dentin disks (8 groups of 3) were polished through 0.25 μm. 12 disks were subjected to an acid challenge (1% citric acid, pH 3.8) for 2 min. The specimens were incubated in artificial saliva, treated by soaking or brushing with deionized (DI) water or a solution of 10% strontium acetate for 2 min twice a day for 28 days. The occlusion percent and nanomechanical properties were determined at the baseline, 5, 14 and 28 days. Cross-sectioned specimens were prepared to evaluate the depth affected by strontium acetate / dentin interaction by SEM. Statistical analysis was performed using linear mixed effects models. A 10% strontium acetate treatment over 5-28 days significantly increased tubule occlusion for normal root dentin and to a lesser extent for demineralized dentin and increased the AFM based nanomechanical properties of demineralized dentin. Brushing was more effective than soaking in recovery of properties of demineralized dentin when treated with strontium. No difference in tubuleocclusion was found between the two delivery methods. Strontium acetate itself proved to have the ability to occlude dentin tubules and result in small changes in the mechanical properties of dentin. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  2. A novel bioactive glass-ceramic for treating dentin hypersensitivity

    Directory of Open Access Journals (Sweden)

    Camila Tirapelli

    2010-12-01

    Full Text Available Dentin hypersensitivity (DH is a painful response to stimulus applied to the open dentinal tubules of a vital tooth. It's a common oral condition, however, without an ideal treatment available yet. This work evaluated in vitro the effect of micron-sized particles from a novel bioactive glass-ceramic (Biosilicate in occluding open dentinal tubules. A dentin disc model was employed to observe comparatively, using scanning electron microscopy (SEM, dentinal tubule occlusion by different products and deposition of hydroxyl carbonate apatite (HCA on dentin surface by Biosilicate, after a single application: G1 - Dentifrice with potassium nitrate and fluoride; G2 - Two-step calcium phosphate precipitation treatment; G3 - Water-free gel containing Biosilicate particles (1%; G4 - Biosilicate particles mixed with distilled water in a 1:10 ratio; all of them after 1, 12 and 24 hours of immersion in artificial saliva. Fourier transform infrared spectroscopy (FTIR was performed to detect HCA formation on dentin discs filled with Biosilicate after 2 minutes, 30 minutes and 12 hours of immersion in artificial saliva. SEM showed a layer of HCA formed on dentin surface after 24 hours by G4. G1, G2 and G3 promoted not total occlusion of open dentinal tubules after 24 hours. FTIR showed HCA precipitation on the dentin surface induced by Biosilicate after 30 minutes. The micron-sized particles from the bioactive glass-ceramic thus were able to induce HCA deposition in open dentinal tubules in vitro. This finding suggests that Biosilicate may provide a new option for treating DH.

  3. O COMPORTAMENTO DA CAUSA PETENDI NOS RECURSOS DE ESTRITO DIREITO – BREVE OBSERVAÇÃO

    OpenAIRE

    Mendonça, João Josué Walmor de

    2008-01-01

    A causa de pedir (causa petendi) no ordenamento jurídico pátrio é fundamental na identificação da demanda e da pretensão do direito de ação do autor desta. Gravita esta causa de pedir em duas correntes doutrinárias que procuram dar relevo no elemento ao qual pugna por ser prevalente em detrimento do outro. Ao observar este instituto processual, aqui, nos recursos de estrito direito, a característica e natureza própria desses recursos, modificam a concepção ordinária do objeto observado, a inv...

  4. Causas de la siniestralidad de las MiPymes en Colombia: factores internos

    OpenAIRE

    Reina Serrano, Daniela; Callejas Mendoza, Marcela

    2015-01-01

    En este artículo se presenta una revisión bibliográfica acerca de los principales factores y causas internas que determinan la siniestralidad de las MiPymes en Colombia -- En él se describe el contexto y la caracterización actual de este tipo de empresas en el país, la importancia de las mismas y las principales causas determinantes de su fracaso -- En este análisis bibliográfico se encontró que las causas internas de la siniestralidad de las MiPymes pueden clasificarse dentro de las siguient...

  5. Causas de la recesión de 1937

    Directory of Open Access Journals (Sweden)

    García Mario

    1993-12-01

    Full Text Available La mayor parte de los logros obtenidos durante el proceso de recuperación que se inicio a partir de 1934 se perdió hacía fines de 1937. Las causas principales de la recesión fueron, a juzgar por los datos que el autor tenía entonces a  su disposición, la especulación en inventarios y la caída en la contribución neta del Gobierno. Esta última, que había sido la fuente de la recuperación, cayó por primera vez en un momento en que los empresarios, ante la posibilidad de encontrarse con diversos cuellos de botella, anticiparon sus pedidos y aumentaron los precios. La confluencia de un nivel excesivo de inventarios y la disminución en las ventas provocaron el derrumbe de la producción y de la actividad económica en general. Otras explicaciones de la recesión, propuestas por diversos autores, carecen, según este enfoque de importancia casual.

    Most of the achievements gained during the period of recovery that began in 1934 were lost cowards the end of 1937. The principal causes of the recession were, to judge from the data the author then had available, speculation in inventories and a fall in government spending. The latter, which had been the source of the recovery , tell for the first time at a moment in which entrepreneurs, faced with the possibility of  diverse bottlenecks, had anticipated their orders and raised prices,The simultaneous occurrence of an excessive level of inventories and the decrease in sales led to the collapse of production and of economic activity in general.Other explanations for the recession proposed by different authors lack causal importance according to this analysis.

  6. Age-related changes in hardness and modulus of elasticity of dentine.

    Science.gov (United States)

    Senawongse, Pisol; Otsuki, Masayuki; Tagami, Junji; Mjör, Ivar

    2006-06-01

    Little knowledge has been clarified about the relationship between the morphological and physical changes of dentine during aging. The purpose of this study was to clarify the modulus of elasticity and hardness related to the morphological changes of dentine by aging using a transmitted light microscope (TLM) and a nano-hardness tester (NHT). Aged human molars and young third molars were used. The dentine morphology was observed under a TLM. The hardness and Young's modulus of elasticity related to the morphologic study were evaluated with an NHT. The thickness of mantle dentine and globular dentine of aged teeth were less than that of young teeth. Transparent dentine was observed only underneath the attrition of young teeth. Reactionary tertiary dentine formed and a "dark zone" was found at the junction between physiologic secondary and reactionary dentine only in aged teeth. At the mantle dentine, hardness and modulus of elasticity of aged dentine were higher than those of young dentine. The reactionary dentine in aged teeth and newly developed secondary dentine in young teeth demonstrated lower modulus of elasticity and hardness than those of other circumpulpal dentine. Relatively low modulus of elasticity and hardness were observed at the zone between secondary and reactionary dentine. Changes in dentine due to aging resulted in transformation of morphological features causing changes to their hardness and modulus of elasticity at the explicit areas such as the increase of hardness and modulus of elasticity at mantle dentin and the reduction of these properties at the "dark zone" that found in aged teeth.

  7. Effect of partially demineralized dentin beneath the hybrid layer on dentin-adhesive interface micromechanics.

    Science.gov (United States)

    Anchieta, Rodolfo Bruniera; Machado, Lucas Silveira; Sundfeld, Renato Herman; Reis, André Figueiredo; Giannini, Marcelo; Luersen, Marco Antonio; Janal, Malvin; Rocha, Eduardo Passos; Coelho, Paulo G

    2015-02-26

    To investigate the presence of non-infiltrated, partially demineralized dentin (PDD) beneath the hybrid layer for self-etch adhesive systems, and its effect on micromechanical behavior of dentin-adhesive interfaces (DAIs). This in-vitro laboratory and computer simulation study hypothesized that the presence of non-infiltrated PDD beneath the hybrid layer does not influence the mechanical behavior of the DAI of self-etch adhesive systems. Fifteen sound third molars were restored with composite resin using three adhesive systems: Scotchbond Multipurpose (SBMP), Clearfil SE Bond (CSEB) and Adper Promp L-Pop (APLP). The thickness and length of all DAIs were assessed using scanning electron microscopy, and used to generate three-dimensional finite element models. Elastic moduli of the hybrid layer, adhesive layer, intertubular dentin, peritubular dentin and resin tags were acquired using a nano-indenter. Finite element software was used to determine the maximum principal stress. Mixed models analysis of variance was used to verify statistical differences (Padhesive systems, as well as the presence and extension of PDD. Both self-etch adhesive systems (APLP and CSEB) had PDD. The DAI stress levels were higher for the one-step self-etch adhesive system (APLP) compared with the etch-and-rinse adhesive system (SBMP) and the self-etch primer system (CSEB). Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Polymerization contraction stress in dentin adhesives bonded to dentin and enamel

    NARCIS (Netherlands)

    Hashimoto, M.; de Gee, A.J.; Feilzer, A.J.

    2008-01-01

    Objective In a previous study on of polymerization contraction stress determinations of adhesives bonded to dentin a continuous decline of stress was observed after the adhesives had been light-cured. The decline was ascribed to stress relief caused by diffusion into the adhesive layer of water

  9. Can interaction of materials with the dentin-pulp complex contribute to dentin regeneration?

    Science.gov (United States)

    Ferracane, Jack L; Cooper, Paul R; Smith, Anthony J

    2010-02-01

    Understanding outcomes of the interaction between a dental material and tooth tissue is important in terms not only of biocompatibility but also of the potential for the material to modulate the response of the tissue. This interaction is influenced by many factors, including the chemistry of the material and any of its eluted components or degradation products, and the manner in which the tissue responds to these agents. Past studies of this interaction have primarily been aimed at identifying cytotoxic effects. More recently, investigations have focused on specific cellular responses, and in particular, on understanding how the materials themselves actually may contribute to regenerative processes in the tooth. Recent work has demonstrated the solubilization of proteins from dentin exposed to certain materials, such as calcium hydroxide, mineral trioxide aggregate, and acidic solutions that relate to those used in dentin bonding agents, with the subsequent modulation by these proteins of gene expression in odontoblast-like cells. This work suggests that dentin bridge formation under such materials may be stimulated through this process. Thus, there is much merit in examining both how new dental materials can be developed and how more traditional ones can be modified to preferentially stimulate regenerative processes when preferred. This review summarizes current knowledge about the potential beneficial effects derived from the interaction of dental materials with the dentin-pulp complex, as well as potential future developments in this exciting field.

  10. Multiphoton imaging of the dentine-enamel junction.

    Science.gov (United States)

    Cloitre, Thierry; Panayotov, Ivan V; Tassery, Hervé; Gergely, Csilla; Levallois, Bernard; Cuisinier, Frédéric J G

    2013-04-01

    Multiphoton microscopy has been used to reveal structural details of dentine and enamel at the dentin-enamel junction (DEJ) based on their 2-photon excited fluorescence (2PEF) emission and second harmonic generation (SHG). In dentine tubule 2PEF intensity varies due to protein content variation. Intertubular dentin produces both SHG and 2PEF signals. Tubules are surrounded by a thin circular zone with a lower SHG signal than the bulk dentine and the presence of collagen fibers perpendicular to the tubule longitudinal axis is indicated by strong SHG responses. The DEJ appears as a low intensity line on the 2PEF images and this was never previously reported. The SHG signal is completely absent for enamel and aprismatic enamel shows a homogeneous low 2PEF signal contrary to prismatic enamel. The SHG intensity of mantle dentine is increasing from the dentine-enamel junction in the first 12 μm indicating a progressive presence of fibrillar collagen and corresponding to the more external part of mantle dentine where matrix metallo-proteases accumulate. The high information content of multiphoton images confirms the huge potential of this method to investigate tooth structures in physiological and pathological conditions. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Tooth dentin defects reflect genetic disorders affecting bone mineralization

    Science.gov (United States)

    Vital, S. Opsahl; Gaucher, C.; Bardet, C.; Rowe, P.S.; George, A.; Linglart, A.; Chaussain, C.

    2012-01-01

    Several genetic disorders affecting bone mineralization may manifest during dentin mineralization. Dentin and bone are similar in several aspects, especially pertaining to the composition of the extracellular matrix (ECM) which is secreted by well-differentiated odontoblasts and osteoblasts, respectively. However, unlike bone, dentin is not remodelled and is not involved in the regulation of calcium and phosphate metabolism. In contrast to bone, teeth are accessible tissues with the shedding of deciduous teeth and the extractions of premolars and third molars for orthodontic treatment. The feasibility of obtaining dentin makes this a good model to study biomineralization in physiological and pathological conditions. In this review, we focus on two genetic diseases that disrupt both bone and dentin mineralization. Hypophosphatemic rickets is related to abnormal secretory proteins involved in the ECM organization of both bone and dentin, as well as in the calcium and phosphate metabolism. Osteogenesis imperfecta affects proteins involved in the local organization of the ECM. In addition, dentin examination permits evaluation of the effects of the systemic treatment prescribed to hypophosphatemic patients during growth. In conclusion, dentin constitutes a valuable tool for better understanding of the pathological processes affecting biomineralization. PMID:22296718

  12. Phosphorus Effects of Mesoporous Bioactive Glass on Occlude Exposed Dentin

    Directory of Open Access Journals (Sweden)

    Wen-Cheng Chen

    2013-11-01

    Full Text Available In recent studies, sealing of exposed dentinal tubules is generally considered as one of the most effective strategies to treat dentin hypersensitivity. Mesoporous bioactive glass (MBG is a potential material for treating dentin hypersensitivity due to its highly specific areas for dissolution and re-precipitated reaction for reduction in dentin permeability. The groups of commercial products of PerioGlas®, synthetic MBG and MBG without phosphorus (MBGNP were compared. The MBG and MBGNP powders were prepared by the sol-gel method and mixed with different calculated ratios of phosphoric acid (PA and then was brushed onto dentin surfaces. We used X-ray diffractometer (XRD, scanning electronic microscope (SEM, and Fourier transform infrared spectroscopy (FTIR to investigate the physiochemistry and the occlusion ability of dentinal tubules. The results showed that MBG paste mixed with PA solution has a better ability for occluding dentinal tubules than MBGNP; it has a short reaction time and good operability. The major crystallite phase of MBG agents was monocalcium phosphate monohydrate [Ca(H2PO42·H2O] in the early stages of the reactions. MBG pastes that were mixed with 30% and 40% PA had the ability to create excellent penetration depth greater than 80 μm. These agents have the potential to treat dentin hypersensitivity.

  13. A novel pyrroleninone cross-link from bovine dentine

    NARCIS (Netherlands)

    Kleter, G.A.; Damen, J.J.M.; Kettenes-Bosch, J.J. van den; Bank, R.A.; Koppele, J.M. te; Veraart, J.R.; Cate, J.M. ten

    1998-01-01

    The aim was to identify suspect collagen cross-links in dentine, eluting close to known cross-links in ion-exchange HPLC. Bovine tooth roots as source of dentine were powdered, demineralised, reduced, and acid-hydrolysed. Cross-linking amino acids were isolated from the acid hydrolysate by size

  14. Staining of dentin from amalgam corrosion is induced by demineralization

    NARCIS (Netherlands)

    Scholtanus, J.D.; van der Hoorn, W.; Özcan, M.; Huysmans, M.C.D.N.J.M.; Roeters, J.F.M.; Kleverlaan, C.J.; Feilzer, A.J.

    2013-01-01

    PURPOSE: To evaluate the effect of artificial demineralization upon color change of dentin in contact with dental amalgam. METHODS: Sound human molars (n = 34) were embedded in resin and coronal enamel was removed. Dentin was exposed to artificial caries gel (pH 5.5) at 37 degrees C for 12 weeks (n

  15. Staining of dentin from amalgam corrosion is induced by demineralization

    NARCIS (Netherlands)

    Scholtanus, Johannes D.; van der Hoorn, Wietske; Huysmans, Marie-Charlotte D. N. J. M.; Roeters, Joost F. M.; Kleverlaan, Cornelis J.; Feilzer, Albert J.; Ozcan, Mutlu

    Purpose: To evaluate the effect of artificial demineralization upon color change of dentin in contact with dental amalgam. Methods: Sound human molars (n= 34) were embedded in resin and coronal enamel was removed. Dentin was exposed to artificial caries gel (pH 5.5) at 37 degrees C for 12 weeks (n=

  16. Infiltration of demineralized dentin with silica and hydroxyapatite nanoparticles.

    Science.gov (United States)

    Besinis, Alexandros; van Noort, Richard; Martin, Nicolas

    2012-09-01

    The management of demineralized dentin resulting from dental caries or acid erosion remains an oral healthcare clinical challenge. This paper investigates, through a range of studies, the ability of colloidal silica and hydroxyapatite (HA) nanoparticles to infiltrate the collagen structure of demineralized dentin. Dentin samples were completely demineralized in 4 N formic acid. The remaining collagen matrix of the dentin samples was subsequently infiltrated with a range of nano-particulate colloidal silica and HA solutions. The effectiveness and extent of the infiltration was evaluated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). Silica nanoparticles have the ability to penetrate dentin and remain embedded within the collagen matrix. It is suggested that particle size plays a major role in the degree of dentin infiltration, with smaller diameter particles demonstrating a greater infiltrative capacity. The infiltration of demineralized dentin with sol-gel HA nanoparticles was limited but was significantly increased when combined with the deflocculating agent sodium hexametaphosphate. The use of acetone as a transport vehicle is reported to enhance the infiltration capacity of sol-gel HA nanoparticles. Collagen infiltrated with HA and silica nanoparticles may provide a suitable scaffold for the remineralization of dentin, whereby the infiltrated particles act as seeds within the collage matrix and given the appropriate remineralizing environment, mineral growth may occur. Copyright © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  17. Detection of dentin antigenic fractions by salivary immunoglobulin G ...

    African Journals Online (AJOL)

    Western blot analysis revealed the presence of dentinal fractions of approximately 35 to 70 kDa in (T12) and (PT) but not in the control samples. In immunoenzymatic assays, the anti-FI salivary IgG levels were significantly higher in T12 and PT groups than in the controls (P< 0.05). Our results demonstrate that dentinal ...

  18. Effect of dentin desensitizing procedures on methyl methacrylate ...

    African Journals Online (AJOL)

    2013-10-29

    Oct 29, 2013 ... crown preparation. Teeth were prepared for a metal supported ceramic crown with 1 mm shoulder margins and then ... Key words: Dentin hypersensitivity, dentin permeability, laser, monomer diffusion, provisional crown. Date of .... There were significant interactions between desensitizing procedures.

  19. La corrupcion en sistemas educativos: una revision de practicas, causas, efectos y recomendaciones

    National Research Council Canada - National Science Library

    Cardenas Denham, Sergio

    2012-01-01

    ... causas, efectos y recomendaciones, asi como la clasificacion de los metodos aplicados para el estudio de las practicas de corrupcion. Por ultimo, se describen las posibles implicaciones de estos hallazgos para los responsables de elaborar las politicas.

  20. Lesiones de causa externa en menores y mayores de 18 anos en un hospital colombiano

    National Research Council Canada - National Science Library

    Bejarano, Monica; Rendon, Luis Fernando

    2009-01-01

    Metodos. Se realizo un analisis de la informacion recabada mediante el Sistema de Vigilancia de Lesiones de Causa Externa del hospital Mario Correa Rengifo de Cali, Colombia, comparando menores y mayores...

  1. Voordrag vir die toekenning van die graad Doctor Educationis, honoris causa, aan prof. dr. Jan Waterink.

    Directory of Open Access Journals (Sweden)

    J. C. Coetzee

    1955-03-01

    Full Text Available Die Raad en die Senaat het op hul vergaderinge in November 1954 besluit om aan prof. dr. Jan Waterink, gebore 20 Oktober 1890, die graad Doctor Educationis honoris causa toe te ken.

  2. Dentin regeneration in vitro: the pivotal role of supportive cells.

    Science.gov (United States)

    About, I

    2011-07-01

    The elaboration of dentin-pulp engineering strategies requires the investigation of not only progenitor cell potentials but also their interactions with other non-progenitor "supportive" cells. Under severe caries lesions, progenitor cells may be activated by growth factors released after the acidic dissolution of carious dentin. However, dentin regeneration has also been observed after traumatic injuries without any significant dentin dissolution. This raises questions about the origin of signals involved in progenitor cell activation, migration, and differentiation. Study models such as the entire tooth culture and co-cultures of pulp and endothelial cells highlighted the role of interactions between the different pulp cell types and the pivotal role they play in dentin regeneration. Injured pulp fibroblasts secrete growth factors involved in progenitor cell activation and differentiation as well as neoangiogenesis which may pave the pathways for progenitor cell migration. This appears to be the first paper to focus on this very important field in dental pulp biology.

  3. On a mathematical model of a human root dentin.

    Science.gov (United States)

    Petrovic, Ljubomir M; Spasic, Dragan T; Atanackovic, Teodor M

    2005-02-01

    On the basis of recent experimental data, a new mathematical model that predicts creep in human root dentin has been developed. The chosen constitutive model comprises fractional derivatives of stress and strain and the restrictions on the coefficients that follow from the Clausius-Duhem inequality. The four constants describing mechanical properties of the human dentin at constant temperature are calculated from a highly non-linear system involving Mittag-Leffler-type functions. Special attention is paid to thermodynamical restrictions that should be observed in determining parameters of the model from experimental results. The proposed model allows us to predict behavior of a human dentin in different load situations. Also it could be used for describing mechanical properties of dentin that are important in the development of 'dentin-like' restorative materials.

  4. Astacin proteases cleave dentin sialophosphoprotein (Dspp) to generate dentin phosphoprotein (Dpp).

    Science.gov (United States)

    Tsuchiya, Shuhei; Simmer, James P; Hu, Jan C-C; Richardson, Amelia S; Yamakoshi, Fumiko; Yamakoshi, Yasuo

    2011-01-01

    Dentin sialophosphoprotein (Dspp) is critical for proper dentin biomineralization because genetic defects in DSPP cause dentin dysplasia type II and dentinogenesis imperfecta types II and III. Dspp is processed by proteases into smaller subunits; the initial cleavage releases dentin phosphoprotein (Dpp). We incubated fluorescence resonance energy transfer (FRET) peptides containing the amino acid context of the Dpp cleavage site (YEFDGKSMQGDDPN, designated Dspp-FRET) or a mutant version of that context (YEFDGKSIEGDDPN, designated mutDspp-FRET) with BMP-1, MEP1A, MEP1B, MMP-2, MMP-8, MMP-9, MT1-MMP, MT3-MMP, Klk4, MMP-20, plasmin, or porcine Dpp and characterized the peptide cleavage products. Only BMP-1, MEP1A, and MEP1B cleaved Dspp-FRET at the G-D peptide bond that releases Dpp from Dspp in vivo. We isolated Dspp proteoglycan from dentin power and incubated it with the three enzymes that cleaved Dspp-FRET at the G-D bond. In each case, the released Dpp domain was isolated, and its N-terminus was characterized by Edman degradation. BMP-1 and MEP1A both cleaved native Dspp at the correct site to generate Dpp, making both these enzymes prime candidates for the protease that cleaves Dspp in vivo. MEP1B was able to degrade Dpp when the Dpp was at sufficiently high concentration to deplete free calcium ion concentration. Immunohistochemistry of developing porcine molars demonstrated that astacins are expressed by odontoblasts, a result that is consistent with RT-PCR analyses. We conclude that during odontogenesis, astacins in the predentin matrix cleave Dspp before the DDPN sequence at the N-terminus of Dpp to release Dpp from the parent Dspp protein. © 2011 American Society for Bone and Mineral Research.

  5. Diagnosis of Dentin Caries – Ultraviolet Fluorescence

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    Uzunov Ts.

    2014-12-01

    Full Text Available The technology advance in recent years determines the need of construction of modern appliances for early diagnosis of dental caries, which are categorized by great precision, non-invasiveness, easy usage and wide availability. Such non-invasive and accurate tool for diagnostics of caries is Caries Detector (LED, Bulgarian product by “Optica Laser”. The detector emits a specific wavelength of near ultraviolet light, which causes fluorescence to porphyrins - metabolic products of the life cycle of caries-inducing bacteria. The purpose of the study is piloting a new diagnostic tool for detection and monitoring of caries excavation based on fluorescence - LED UV caries detector of company “Optica laser”. Subjected to examination by caries indicator dye and UV caries detector were sixty permanent teeth with deep dentine caries. Two methods were used to assess the dentin caries - UV fluorescence detector of “Optica Laser” and staining with caries indicator - dye (Sable ™ Seek®. It was found that among all sixty teeth, the fields, closed by margins of carious process overlap. Fifty-four of tested teeth has shown bigger field of images with staining method and six - smaller in comparison to the fluorescent method. Ultraviolet fLuorescence caries detector of “Optica Laser” company is affordable and easy applicable method for controlled excavation of dentine caries. The detector can be used in daily dental practice equally with other methods. The unit has a number of advantages - non-invasiveness, lack of interaction with tooth structures, speed, reliability, efficiency, predictability and repeatability of results.

  6. Investigation of Biodentine as dentine replacement material.

    Science.gov (United States)

    Camilleri, Josette

    2013-07-01

    Biodentine was compared to glass ionomer and resin modified cements in an "open sandwich" restoration. Fuji IX, Vitrebond and Biodentine were characterised using various techniques. The effect of etching with 35% phosphoric acid was investigated by assessment of surface topography, Fourier transform infrared (FT-IR) spectroscopy, surface micro-hardness and micro-leakage using tagged carboxylated-modified fluorescent microspheres and tracing the presence of these particles with a confocal microscope. Acid etching resulted in erosion of the material surface with exposure of the glass particles in the glass ionomer-based materials. Biodentine exhibited a reduction in the chlorine peak and the calcium-silicon ratio. There was no difference in the micro-hardness in etched and un-etched materials. The FT-IR plots did not show any chemical changes caused by etching for all the materials investigated. Both Vitrebond and Fuji IX exhibited no leakage at the dentine to material interface while Biodentine exhibited leakage both when it was etched and also when the surface was left unprepared. The sandwich technique was effective and prevented micro-leakage with glass ionomer-based materials but micro-leakage occurred with Biodentine. Biodentine demonstrated both structural and chemical changes when etched with 37% phosphoric acid. Biodentine exhibited a lower calcium to silicon ratio and a reduction in the chloride peak height when etched. When used as a dentine replacement material in the sandwich technique overlayed with composite, significant leakage occurred at the dentine to material interface. On the other hand materials based on glass ionomer cement were etched successfully and no chemical and physical changes or micro-leakage were detected when the materials were used as bases under composite restorations. The micro-hardness of all the materials was unaffected by etching. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Tabulador de causas múltiplas de morte Multiple causes- of-death tabulator

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    Augusto H. Santo

    1999-08-01

    Full Text Available O uso de causas múltiplas de morte vem sendo atualmente preconizado para descrever e analisar os determinantes patológicos da mortalidade em populações, como complemento ao uso tradicional da causa básica de morte. O estudo das causas múltiplas pode realizar-se por meio da apresentação de todas as menções das causas básicas e associadas de morte e por meio de associações de causas. Um programa para microcomputador foi desenvolvido para processar bancos de dados contendo as causas de morte informadas no Modelo Internacional de Atestado Médico de Causa de Morte, denominado Tabulador de Causas Múltiplas, que gera uma tabela matriz a partir da qual podem ser derivadas as demais formas de apresentação e análise, além de poder ser usado como instrumento de crítica dos dados de mortalidade.The use of multiple-causes-of-death is currently being recommended in order to describe and analyze the pathological determinants of mortality in populations, as a supplement to the traditional use of the underlying cause of death. Multiple-causes-of-death can be studied by presenting all underlying and associated causes mentioned, and by means of associations of causes of death. Microcomputer software has been developed to process data files containing causes of death informed by physicians on the International Form of Medical Certificate of Causes of Death. The Multiple Cause of Death Tabulator software generates a matrix table from which the above forms of presentation and analysis can be achieved and mortality data be edited.

  8. Selected variables in bonding to dentin.

    Science.gov (United States)

    Uno, S; Asmussen, E

    1992-04-01

    The aim of this study was to investigate the effect of three variables on the shear bond strength between a composite resin and dentin treated with a simplified Gluma system. Thickness of material (2 or 3 mm), distance between light guide and the surface of composite resin (0, 1, 3, or 5 mm) and irradiation time (10, 20, 40, or 60 s) were selected as variables. Thickness of material and distance between light guide and composite resin affected bond strength, but there was little influence of irradiation time under the conditions of the study. It is suggested that bond strength depends on the amount of light transmitted through the composite.

  9. Mortalidad por causas externas en Medellín, 1999-2006

    Directory of Open Access Journals (Sweden)

    Doris Cardona Arango

    2008-01-01

    Full Text Available Caracterizar el comportamiento de la mortalidad por causas externas en la ciudad de Medellín, Colombia, entre 1999-2006, según sexo, edad y causa básica de muerte fue el objetivo de este estudio descriptivo longitudinal, con fuente de información secundaria de 22 128 registros de defunción por causas externas. El análisis realizado es univariado y bivariado por sexo, grupos de edad y causa de muerte. Las causas externas registradas en el periodo fueron: 72.9 por ciento por homicidio; 15.3 por ciento, accidente de transporte; 7.3 por ciento, traumatismos; 4.2 por ciento, por suicidio, y por otras causas, 0.4 por ciento. La mayor tasa de mortalidad se presentó en el grupo de edad de 20 a 24 años (27.6 por cien mil habitantes, hecho que merece especial consideración por las implicaciones sociales, familiares y laborales que representa el fallecimiento de una persona en su etapa productiva.

  10. On the configuration of incremental lines in human dentine as revealed by tetracycline labelling.

    Science.gov (United States)

    Kawasaki, K

    1975-02-01

    The pattern of tetracycline labelling in dentine was investigated in ground sections of human teeth under visible and ultraviolet light. The tetracycline lines presented different appearances near the enamel-junction region, near the dentine-cementum junction, in the mantle dentine, and in the circumpulpal dentine, depending on whether the mineralization front was linear, globular or linear-globular.

  11. Changes in dimensions and weight of human dentine after different drying procedures and during subsequent rehydration

    NARCIS (Netherlands)

    Van der Graaf, E R; Ten Bosch, J J

    Shrinkage of dentine and the decrease in its weight after drying were measured. Three drying procedures were used, freeze-drying and drying in nitrogen at 60 and 100 degrees C. The dentine was subsequently rehydrated while measuring its dimensions. Rehydrated dentine was weighed. Dentine weight

  12. Bioactive glass for dentin remineralization: A systematic review.

    Science.gov (United States)

    Fernando, Delihta; Attik, Nina; Pradelle-Plasse, Nelly; Jackson, Phil; Grosgogeat, Brigitte; Colon, Pierre

    2017-07-01

    Strategies to achieve dentin remineralization is at present an important target of restorative dentistry. Remineralization of dentin by a bioactive material is complete only when the tissue regains its functionality. This is achieved when there is adequate apatite formation which most importantly translates into improved mechanical properties of dentin as a result of intrafibrillar mineralization. Bioactive glass (BAG) is a well-known implant material for bone regeneration and is proven to have excellent ability of apatite formation. Hence, recent studies have proposed BAGs as one of the most desired materials for remineralization of dentin. Therefore the aim of this systematic review was to scope the evidence of bioactive glass to remineralize dentin. The following research question was formulated: "Is there strong evidence for bioactive glass to remineralize dentin?" Three databases (Web of science, PubMed and Science direct) were scanned independently following PRISMA guidelines. Inclusion and exclusion criteria were set to identify relevant articles based on title and abstract screening. Finally, potentially relevant articles were downloaded and the full text was scrutinized to select the articles included in this review. The first phase of search returned 303 articles. A total of 19 papers with full text were scrutinized for inclusion, of which 3 papers were chosen for the final synthesis. All three studies confirm that BAG treatment leads to enhanced apatite formation in dentin. Only 1 of the 3 studies has reported the mechanical properties of dentin after BAG treatment and it revealed that the Young's modulus and flexural bend strength of BAG treated dentin were much lower than natural dentin even though they had similar apatite content. This review highlights the importance of assessing the mechanical properties of dentin alongside to the newly formed apatite content in order to prove BAGs efficiency to remineralize this tissue. Though studies have

  13. Effect of pulsed Nd:YAG on dentin morphological changes

    Science.gov (United States)

    Moriyama, Eduardo H.; Zangaro, Renato A.; Villaverde, Antonio G. J. B.; Watanabe-Sei, Ii; Munin, Egberto; Sasaki, Luis H.; Otsuka, Daniel K.; Lobo, Paulo D. d. C.; Pacheco, Marcos T. T.; Junior, Durval R.

    2002-06-01

    Infrared lasers have been used for several clinical applications in dentistry, including laser ablation, oral surgeries and dentin hypersensitivity treatment. Despite of dentin low absorption coefficient in the near infrared spectrum, Nd:YAG laser radiation ((lambda) = 1064 nm) is able to melt the human dentin surface resulting in dentin tubules closure that can suppress the symptoms of dentin hypersensitivity pathology. Objectives: This study aims to analyze, through SEM technique, the morphological changes in dentin surface after Nd:YAG laser irradiation using different parameters in energy distribution. Materials and Methods: In this study sixteen human dentin samples were submitted to Nd:YAG laser radiation using a total energy of 900mJ distributed in one, two, three or six laser pulses with energy for each pulse of 900, 450, 300 or 150 mJ respectively. All the samples were irradiated with laser pulse width of 90ms, pulse intervals of 300 ms and spot size area of 0,005 cm2. Results: SEM analysis suggests that differences in energy distribution results in morphological differences even though the same energy is used for all the samples.

  14. Remineralizing Efficacy of Fluorohydroxyapatite Gel on Artificial Dentinal Caries Lesion

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    Qianqian Wang

    2015-01-01

    Full Text Available The aim was to evaluate the remineralizing efficacy of fluorohydroxyapatite (FHA gel on artificial dentinal caries lesion in vitro. Artificial carious lesions were made on occlusal cavities of teeth by exposing the dentin surface to a demineralizing solution. Each cavity was capped with a 3 mm thick FHA gel for 4 weeks. After the FHA gel was removed, the surface morphology and structure of the dentin were characterized by scanning electron microscopy (SEM, energy-dispersive X-ray spectroscopy (EDX, X-ray diffraction (XRD, and Fourier transform infrared spectroscopy (FT-IR. The dentin mineral density (DMD was measured by micro-computed tomography (Micro-CT. A layer of dense and orderly hexagonal crystal structure, with average diameter of 1 μm and thickness of 4~5 μm, could be observed on dentin surface. These crystals exhibited elemental peaks for calcium, phosphorus, carbon, and oxygen and characteristic peaks of hydroxyapatite (HA and fluorapatite (FA via XRD and FT-IR. The DMD of dentin surface layer significantly increased after it was capped with FHA gel (P<0.05. In the present study, the FHA gel could rapidly construct apatite on the artificial dentin caries surface and significantly increase the mineral density, which suggests that FHA gel might be a proper IPT material with remineralizing function.

  15. Characterization of Dentine to Assess Bond Strength of Dental Composites

    Science.gov (United States)

    Liaqat, Saad; Aljabo, Anas; Khan, Muhammad Adnan; Ben Nuba, Hesham; Bozec, Laurent; Ashley, Paul; Young, Anne

    2015-01-01

    This study was performed to develop alternating dentine adhesion models that could help in the evaluation of a self-bonding dental composite. For this purpose dentine from human and ivory was characterized chemically and microscopically before and after acid etching using Raman and SEM. Mechanical properties of dentine were determined using 3 point bend test. Composite bonding to dentine, with and without use of acid pre-treatment and/or the adhesive, were assessed using a shear bond test. Furthermore, micro gap formation after restoration of 3 mm diameter cavities in dentine was assessed by SEM. Initial hydroxyapatite level in ivory was half that in human dentine. Surface hydroxyapatites decreased by approximately half with every 23 s of acid etch. The human dentine strength (56 MPa) was approximately double that of ivory, while the modulus was almost comparable to that of ivory. With adhesive use, average shear bond strengths were 30 and 26 MPa with and without acid etching. With no adhesive, average bond strength was 6 MPa for conventional composites. This, however, increased to 14 MPa with a commercial flowable “self–bonding” composite or upon addition of low levels of an acidic monomer to the experimental composite. The acidic monomer additionally reduced micro-gap formation with the experimental composite. Improved bonding and mechanical properties should reduce composite failures due to recurrent caries or fracture respectively.

  16. Characterization of Dentine to Assess Bond Strength of Dental Composites

    Directory of Open Access Journals (Sweden)

    Saad Liaqat

    2015-04-01

    Full Text Available This study was performed to develop alternating dentine adhesion models that could help in the evaluation of a self-bonding dental composite. For this purpose dentine from human and ivory was characterized chemically and microscopically before and after acid etching using Raman and SEM. Mechanical properties of dentine were determined using 3 point bend test. Composite bonding to dentine, with and without use of acid pre-treatment and/or the adhesive, were assessed using a shear bond test. Furthermore, micro gap formation after restoration of 3 mm diameter cavities in dentine was assessed by SEM. Initial hydroxyapatite level in ivory was half that in human dentine. Surface hydroxyapatites decreased by approximately half with every 23 s of acid etch. The human dentine strength (56 MPa was approximately double that of ivory, while the modulus was almost comparable to that of ivory. With adhesive use, average shear bond strengths were 30 and 26 MPa with and without acid etching. With no adhesive, average bond strength was 6 MPa for conventional composites. This, however, increased to 14 MPa with a commercial flowable “self–bonding” composite or upon addition of low levels of an acidic monomer to the experimental composite. The acidic monomer additionally reduced micro-gap formation with the experimental composite. Improved bonding and mechanical properties should reduce composite failures due to recurrent caries or fracture respectively.

  17. Dentin biomodification: strategies, renewable resources and clinical applications.

    Science.gov (United States)

    Bedran-Russo, Ana K; Pauli, Guido F; Chen, Shao-Nong; McAlpine, James; Castellan, Carina S; Phansalkar, Rasika S; Aguiar, Thaiane R; Vidal, Cristina M P; Napotilano, José G; Nam, Joo-Won; Leme, Ariene A

    2014-01-01

    The biomodification of dentin is a biomimetic approach, mediated by bioactive agents, to enhance and reinforce the dentin by locally altering the biochemistry and biomechanical properties. This review provides an overview of key dentin matrix components, targeting effects of biomodification strategies, the chemistry of renewable natural sources, and current research on their potential clinical applications. The PubMed database and collected literature were used as a resource for peer-reviewed articles to highlight the topics of dentin hierarchical structure, biomodification agents, and laboratorial investigations of their clinical applications. In addition, new data is presented on laboratorial methods for the standardization of proanthocyanidin-rich preparations as a renewable source of plant-derived biomodification agents. Biomodification agents can be categorized as physical methods and chemical agents. Synthetic and naturally occurring chemical strategies present distinctive mechanism of interaction with the tissue. Initially thought to be driven only by inter- or intra-molecular collagen induced non-enzymatic cross-linking, multiple interactions with other dentin components are fundamental for the long-term biomechanics and biostability of the tissue. Oligomeric proanthocyanidins show promising bioactivity, and their chemical complexity requires systematic evaluation of the active compounds to produce a fully standardized intervention material from renewable resource, prior to their detailed clinical evaluation. Understanding the hierarchical structure of dentin and the targeting effect of the bioactive compounds will establish their use in both dentin-biomaterials interface and caries management. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  18. Dietary adaptions in the ultrastructure of dinosaur dentine.

    Science.gov (United States)

    Brink, Kirstin S; Chen, Yu-Cheng; Wu, Ya-Na; Liu, Wei-Min; Shieh, Dar-Bin; Huang, Timothy D; Sun, Chi-Kuang; Reisz, Robert R

    2016-12-01

    Teeth are key to understanding the feeding ecology of both extant and extinct vertebrates. Recent studies have highlighted the previously unrecognized complexity of dinosaur dentitions and how specific tooth tissues and tooth shapes differ between taxa with different diets. However, it is unknown how the ultrastructure of these tooth tissues contributes to the differences in feeding style between taxa. In this study, we use third harmonic generation microscopy and scanning electron microscopy to examine the ultrastructure of the dentine in herbivorous and carnivorous dinosaurs to understand how the structure of this tissue contributes to the overall utility of the tooth. Morphometric analyses of dentinal tubule diameter, density and branching rates reveal a strong signal for dietary preferences, with herbivorous saurischian and ornithischian dinosaurs consistently having higher dentinal tubule density than their carnivorous relatives. We hypothesize that this relates to the hardness of the dentine, where herbivorous taxa have dentine that is more resistant to breakage and wear at the dentine-enamel junction than carnivorous taxa. This study advocates the detailed study of dentine and the use of advanced microscopy techniques to understand the evolution of dentition and feeding ecology in extinct vertebrates. © 2016 The Author(s).

  19. Diabetes detrimental effects on enamel and dentine formation.

    Science.gov (United States)

    Abbassy, M A; Watari, I; Bakry, A S; Hamba, H; Hassan, Ali H; Tagami, J; Ono, T

    2015-05-01

    Understanding morphological changes and mineral content of tooth hard tissues may influence dental treatment. In this study, the effect of Type 1 Diabetes Mellitus (T1DM) on tooth structure was examined. Experimental T1DM was induced in 3-week old male Wistar rats (n=10) by a single dose of 60mg/kg body weight of Streprozotocin. All rats were injected with calcein twice during the experiment and sacrificed at the age of 7 weeks old. Micro-computed tomography (micro-CT) was used to determine the mineral density and thickness of enamel and dentine. Also, a histomorphometery study was conducted to detect the rates of dentine mineral apposition and formation. The examined area was in the crown analogue of the rat mandibular incisor parallel to the long axis of the mesial surface of the first molar. All results were compared using Students' t-test (penamel and dentine thickness were significantly reduced (hypoplasia) and there was a significant reduction of the rate of dentine mineral apposition and formation, while there was no significant effect of the T1DM condition on the mineral density of enamel and dentine. T1DM has a detrimental influence on the formation of enamel and dentine in the early growth stage. T1DM condition may alter treatment planning of orthodontic treatment as it is associated with decreased enamel and dentin thickness that may affect teeth size and their resistance to caries. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. A micromechanics model of the elastic properties of human dentine

    Energy Technology Data Exchange (ETDEWEB)

    Kinney, J. H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Balooch, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Marshall, G. W. [Univ. of California, San Francisco, CA (United States). Dept. of Restorative Dentistry; Marshall, S. J. [Univ. of California, San Francisco, CA (United States). Dept. of Restorative Dentistry

    1999-10-01

    A generalized self-consistent model of cylindrical inclusions in a homogeneous and isotropic matrix phase was used to study the effects of tubule orientation on the elastic properties of dentin. Closed form expressions for the five independent elastic constants of dentin were derived in terms of tubule concentration, and the Young's moduli and Poisson ratios of peri- and intertubular dentin. An atomic force microscope (AFM) indentation technique determined the Young's moduli of the peri- and intertubular dentin as approximately 30 GPa and 15 GPa, respectively. Over the natural variation in tubule density found in dentin, there was only a slight variation in the axial and transverse shear moduli with position in the tooth, and there was no measurable effect of tubule orientation. We conclude that tubule orientation has no appreciable effect on the elastic behavior of normal dentin, and that the elastic properties of healthy dentin can be modeled as an isotropic continuum with a Young's modulus of approximately 16 GPa and a shear modulus of 6.2 GPa.

  1. The distribution of magnesium in developing rat incisor dentin

    Energy Technology Data Exchange (ETDEWEB)

    Steinfort, J.; Driessens, F.C.; Heijligers, H.J.; Beertsen, W. (Academic Centre for Dentistry Amsterdam (ACTA) (Netherlands))

    1991-03-01

    Previous studies have shown that rat incisor dentin contains a considerable amount of magnesium that is distributed heterogeneously. The cementum-related dentin, especially its incisal portion, is richest in magnesium. It was the purpose of the present study to investigate the changes that occur in the magnesium content during dentin maturation. Cross-sections were prepared from rat incisors at the apical, middle, and incisal levels. By means of an electron microprobe, tracings were made of the Ca-, Mg-, and P- signal frequencies. Comparison of corresponding dentin layers within and between the cross-sections showed that the Mg/P molar ratio was always higher in the cementum-related dentin (CRD) than in the enamel-related dentin (ERD) and increased from the apex toward the incisal edge. Especially in the incisal cross-section, an increase in Mg/P was found from the older (peripheral) toward the younger (central) dentin layers. As the Mg/P ratio varied from 0.07 to 0.33, the Ca/P ratio was found to fluctuate from 1.48 to 1.15. The two ratios appeared to be highly correlated (r = -0.97; p less than 0.001), suggesting that Mg replaces Ca and is bound to phosphate.

  2. Shear bond strength of glass-ionomer adhesive to dentin: effect of smear layer thickness and different dentin conditioners.

    Science.gov (United States)

    El-Askary, Farid S; Nassif, Mohammed S; Fawzy, Amr S

    2008-12-01

    To investigate the effect of two different smear layer thicknesses treated with different dentin conditioners on the bond strength of glass-ionomer adhesive to dentin. Fifty human molars were used. Each tooth was sectioned in a mesiodistal direction into halves, using a low-speed diamond disk. The 100 halves were randomly divided into 10 equal groups. Groups I to V for the thick smear layer and groups VI to X for the thin smear layer. Eighty halves were used for shear bond strength testing, while the remaining 20 halves were used for SEM evaluation of the adhesive/dentin interface. After each dentin pretreatment, the glass-ionomer adhesive was applied over the conditioned dentin surfaces for all tested groups and restored with resin composite cylinders. Each half with its attached composite cylinder was subjected to shear load at crosshead speed of 0.5 mm/min until failure occurred. The dentin surfaces for SEM evaluation were treated as described for shear bond strength testing. The samples were examined using SEM operated at 30 kv, and the resin/dentin interface was examined at 1500X. Two-way ANOVA showed that there was no significant effect of the smear layer thickness on shear bond strength. There was a significant effect of the different conditioners used (p = 0.001). The interaction of the two independent variables (smear layer thickness and the dentin conditioners) showed no significant difference in the shear bond strength to dentin. The common feature in all evaluated specimen interfaces was the presence of a hybrid layer of different thicknesses with no visible resin tags. The shear bond strength of the glass-ionomer adhesive to dentin proved to be independent of the smear layer thickness. The use of dentin conditioner prior to the application of the glass-ionomer adhesive appeared to be an important step to improve its bond strength to dentin. Glass-ionomer adhesive failed to produce resin tags regardless of the type of dentin conditioner used.

  3. The influence of age and depth of dentin on bonding.

    Science.gov (United States)

    Burrow, M F; Takakura, H; Nakajima, M; Inai, N; Tagami, J; Takatsu, T

    1994-07-01

    The purpose of this study was to investigate what influence the two variables of dentin depth and age may have on the tensile bond strengths of three bonding systems. Dentin discs prepared from human molars were divided into young and old, superficial and deep surfaces. Three bonding systems, Scotchbond Multi-purpose (3M Dental Products), Superbond D-liner (Sun Medical Co.), and Liner Bond II (Kuraray Co.) were the materials tested for tensile bond strength. In addition, the structural variation of the resin-impregnated, or hybrid, layer was compared among the two variables and three bonding systems. Tensile bond strengths exceeding 10 MPa were obtained for all materials. After ANOVA, an effect on tensile bond strength could be attributed to dentin age or depth for only Superbond D-liner used on deep-young dentin as compared with old-superficial dentin. All other group comparisons failed to show any variation between dentin depth or age. However, specimens bonded to deeper dentin showed slightly lower strengths. SEM observations showed thicker resin-impregnated layers for Scotchbond MP and Superbond D-liner compared with Liner Bond II. Liner Bond II exhibited a thinner and more diffuse resin-impregnated layer, believed to be due to the different dentin conditioning method. Dentin age or depth may not show as great an influence on bond strengths with the newer type of bonding systems. The resin-impregnated layer quality, rather than thickness, is believed to be the most important factor for obtaining high tensile bond strengths.

  4. Dentinal tubules revealed with X-ray tensor tomography.

    Science.gov (United States)

    Jud, Christoph; Schaff, Florian; Zanette, Irene; Wolf, Johannes; Fehringer, Andreas; Pfeiffer, Franz

    2016-09-01

    Dentin is a mineralized material making up most of the tooth bulk. A system of microtubules, so called dentinal tubules, transverses it radially from the pulp chamber to the outside. This highly oriented structure leads to anisotropic mechanical properties directly connected to the tubules orientation and density: the ultimate tensile strength as well as the fracture toughness and the shear strength are largest perpendicular to dentinal tubules. Consequently, the fatigue strength depends on the direction of dentinal tubules, too. However, none of the existing techniques used to investigate teeth provide access to orientation and density of dentinal tubules for an entire specimen in a non-destructive way. In this paper, we measure a third molar human tooth both with conventional micro-CT and X-ray tensor tomography (XTT). While the achievable resolution in micro-CT is too low to directly resolve the dentinal tubules, we provide strong evidence that the direction and density of dentinal tubules can be indirectly measured by XTT, which exploits small-angle X-ray scattering to retrieve a 3D map of scattering tensors. We show that the mean directions of scattering structures correlate to the orientation of dentinal tubules and that the mean effective scattering strength provides an estimation of the relative density of dentinal tubules. Thus, this method could be applied to investigate the connection between tubule orientation and fatigue or tensile properties of teeth for a full sample without cutting one, non-representative peace of tooth out of the full sample. Copyright © 2016 The Academy of Dental Materials. All rights reserved.

  5. Adhesive sealing of dentin surfaces in vitro: A review

    Science.gov (United States)

    Abu-Nawareg, Manar M; Zidan, Ahmed Z; Zhou, Jianfeng; Agee, Kelli; Chiba, Ayaka; Tagami, Jungi; Pashley, David H

    2016-01-01

    Purpose The purpose of this review is to describe the evolution of the use of dental adhesives to form a tight seal of freshly prepared dentin to protect the pulp from bacterial products, during the time between crown preparation and final cementum of full crowns. The evolution of these “immediate dentin sealants” follows the evolution of dental adhesives, in general. That is, they began with multiple-step, etch-and-rinse adhesives, and then switched to the use of simplified adhesives. Methods Literature was reviewed for evidence that bacteria or bacterial products diffusing across dentin can irritate pulpal tissues before and after smear layer removal. Smear layers can be solubilized by plaque organisms within 7–10 days if they are directly exposed to oral fluids. It is likely that smear layers covered by temporary restorations may last more than one month. As long as smear layers remain in place, they can partially seal dentin. Thus, many in vitro studies evaluating the sealing ability of adhesive resins use smear layer-covered dentin as a reference condition. Surprisingly, many adhesives do not seal dentin as well as do smear layers. Results Both in vitro and in vivo studies show that resin-covered dentin allows dentinal fluid to cross polymerized resins. The use of simplified single bottle adhesives to seal dentin was a step backwards. Currently, most authorities use either 3-step adhesives such as Scotchbond Multi-Purposea or OptiBond FLb or two-step self-etching primer adhesives, such as Clearfil SEc, Unifil Bondd or AdheSEe, respectfully. PMID:26846037

  6. Use of poly (amidoamine dendrimer for dentinal tubule occlusion: a preliminary study.

    Directory of Open Access Journals (Sweden)

    Tianda Wang

    Full Text Available The occlusion of dentinal tubules is an effective method to alleviate the symptoms caused by dentin hypersensitivity, a significant health problem in dentistry and daily life. The in situ mineralization within dentinal tubules is a promising treatment for dentin hypersensitivity as it induces the formation of mineral on the sensitive regions and occludes the dentinal tubules. This study was carried out to evaluate the in vitro effect of a whole generation poly(amidoamine (PAMAM dendrimer (G3.0 on dentinal tubule occlusion by inducing mineralization within dentinal tubules. Dentin discs were treated with PAMAM dendrimers using two methods, followed by the in vitro characterization using Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR, X-ray diffraction (XRD, Field emission scanning electron microscopy (FE-SEM and Energy-Dispersive X-ray Spectroscopy (EDS. These results showed that G3.0 PAMAM dendrimers coated on dentin surface and infiltrated in dentinal tubules could induce hydroxyapatite formation and resulted in effective dentinal tubule occlusion. Moreover, crosslinked PAMAM dendrimers could induce the remineralization of demineralized dentin and thus had the potential in dentinal tubule occlusion. In this in vitro study, dentinal tubules occlusion could be achieved by using PAMAM dendrimers. This could lead to the development of a new therapeutic technique for the treatment of dentin hypersensitivity.

  7. Meta-analytical Review of Parameters Involved in Dentin Bonding

    OpenAIRE

    de Munck, Jan; Mine, A.; Poitevin, André; Van Ende, Annelies; Cardoso, M Vivan; Van Landuyt, Kirsten; Peumans, Marleen; Van Meerbeek, Bart

    2012-01-01

    Bond-strength testing is the method most used for the assessment of bonding effectiveness to enamel and dentin. We aimed to disclose general trends in adhesive performance by collecting dentin bond-strength data systematically. The PubMed and EMBASE databases were used to identify 2,157 bond-strength tests in 298 papers. Most used was the micro-tensile test, which appeared to have a larger discriminative power than the traditional macro-shear test. Because of the huge variability in dentin bo...

  8. Microtensile bond strength to Er:YAG laser pretreated dentin

    OpenAIRE

    da Graça Lopes, Roberta Marques; Special Laboratory of Lasers in Dentistry (LELO) – Department of Restorative Dentistry – School of Dentistry – University of São Paulo (USP) – São Paulo – SP – Brazil.; Steiner-Oliveira, Carolina; Special Laboratory of Lasers in Dentistry (LELO) – Department of Restorative Dentistry – School of Dentistry – University of São Paulo (USP) – São Paulo – SP – Brazil.; Aranha, Ana Cecília Côrrea; Special Laboratory of Lasers in Dentistry (LELO) – Department of Restorative Dentistry – School of Dentistry – University of São Paulo (USP) – São Paulo – SP – Brazil.; Castellan, Carina Strano; Department of Dental Materials – School of Dentistry – University of São Paulo (USP) – São Paulo – SP – Brazil.; Bello-Silva, Marina Stella; Special Laboratory of Lasers in Dentistry (LELO) – Department of Restorative Dentistry – School of Dentistry – University of São Paulo (USP) – São Paulo – SP – Brazil. Center for Reseacrh and Innovation in Laser – Universidade Nove de Julho – São Paulo – SP – Brazil.; Dias Vieira Júnior, Nilson; Center of Lasers and Applications – Energy and Nuclear Research Institute (IPEN) – São Paulo – SP – Brazil.; de Paula Eduardo, Carlos; Special Laboratory of Lasers in Dentistry (LELO) – Department of Restorative Dentistry – School of Dentistry – University of São Paulo (USP) – São Paulo – SP – Brazil.

    2014-01-01

    Objective: Although the effects of Er:YAG  (erbium:yttrium aluminium garnet) laser on cavity  preparation as well as on dentin bonding to composite  have been described in the literature, the longevity of  this bond is still unknown. So, this study evaluated the  short-term microtensile bond strength to dentin samples  after different protocols of surface treatment. Materials  and Methods: 60 bovine incisors were cleaned, worn  to expose a dentin area and subdivided into groups  according to ...

  9. The measurement in vitro of dentine abrasion by toothpastes.

    Science.gov (United States)

    Vicentini, Bruna Carvalho; Braga, Sheila Regina Maia; Sobral, Maria Angela Pita

    2007-10-01

    To investigate the in vitro dentine wear after tooth brushing with a range of nine toothpastes. 70 bovine dentine blocks (aproximately 1 cm long) were used. Specimens were brushed in vitro with toothpastes with a range of abrasive. All the specimens were submitted to 10,000 brushing cycles with a 200g load. Initial and final weight and profile data were obtained using an analytical scale and a profile projector respectively. Significant differences between the test products were found (p whitening toothpastes. This study demonstrated that the type of toothpaste abrasive can contribute to dentine wear.

  10. Decreased dentin tubules density and reduced thickness of peritubular dentin in hyperbilirubinemia-related green teeth

    OpenAIRE

    Neves-Silva, Rodrigo; Alves, Fabio A.; Antunes, Alberto; Goes, Mario Fernando; Giannini, Marcelo; Tenório, Maria-Dânia; Machado, José Lécio; Paes Leme, Adriana Franco; Lopes, Márcio Ajudarte; Santos Silva, Alan Roger

    2017-01-01

    Background It is stated anecdotally that patients with liver diseases in childhood who develop green teeth have increased risk for rampant caries, which may be secondary to changes in dental structure. The aim of this study was to test the hypothesis that hyperbilirubinemia affects the dentin morphology of green teeth. Material and Methods Sixteen primary teeth were prepared and divided into two groups (green teeth, n = 8 and control, n = 8), which were transversely fractured across the cervi...

  11. Zn-doped etch-and-rinse model dentin adhesives: Dentin bond integrity, biocompatibility, and properties.

    Science.gov (United States)

    Barcellos, Daphne Câmara; Fonseca, Beatriz Maria; Pucci, César Rogério; Cavalcanti, Bruno das Neves; Persici, Erasmo De Souza; Gonçalves, Sérgio Eduardo de Paiva

    2016-07-01

    This study assessed a 6 month resin/dentin bond's durability and cytotoxic effect of Zn-doped model dentin adhesives. The mechanical and physicochemical properties were also tested. A model etch-and-rinse single-bottle adhesive was formulated (55wt.% Bis-GMA, 45wt.% HEMA, 0.5wt.% CQ, 0.5wt.% DMAEMA) and Zinc methacrylate (Zn-Mt) or ZnO nanoparticles (ZnOn) were added to the model's adhesive, resulting in three groups: Group Control (control model adhesive); Group Zn-Mt (1wt.% Zn-Mt incorporated to adhesive) and Group ZnOn (1wt.% ZnOn incorporated to adhesive). The microtensile bond strength (mTBS) was assessed after 24h or 6 months in water storage. Mechanical properties (diametral tensile strength/DTS, flexural strength/FS, flexural modulus/FM, resilience modulus/RM, and compressive strength/CS) and physicochemical properties (polymerization shrinkage/PS, contact angle/CA, water sorption/WS, and water solubility/WS) were also tested. Cytotoxicity was evaluated with SRB biochemical assay. No significant difference in the DTS, FS, FM, CS, CA, WS, and WS were found when 1% of ZnOn or Zn-Mt was added to the model dentin adhesive. Group Zn-Mt decreased the RM of adhesive. Groups Zn-Mt and ZnOn decreased the PS of adhesives. Group ZnOn reduced the cytotoxicity of adhesive. Group ZnOn preserved mTBS after 6 months storage without degradation areas as seen by SEM analysis. The 1wt.% ZnOn may preserve the integrity of the hybrid layer and may reduce cytotoxicity and polymerization shrinkage of model dentin adhesive. The addition of Zn-Mt to the adhesive had no beneficial effects. Copyright © 2016 The Academy of Dental Materials. All rights reserved.

  12. Differences between micro-hardness affected dentin after mechanical or chemo-mechanical infected dentin disposal (laboratory experiment)

    Science.gov (United States)

    Ihsani, V.; Nursasongko, B.; Djauharie, N.

    2017-08-01

    The concept of conserving healthy tooth structures during cavity preparation has gained popularity with chemo-mechanical caries removal. This study compared three methods of caries removal using: a chemo-mechanical caries removal papain gel; Papacarie® (these contain natural ingredients, mainly papain enzyme); and mechanical preparation with a bur rotary instrument. The purpose of this study was to compare affected dentin micro-hardness after removal of infected dentin with mechanical and chemo-mechanical techniques. Twenty-seven permanent molar teeth were randomly divided into three groups receiving removal of infected dentin. These were: Group 1: chemo-mechanical technique using papain gel; Group 2: chemo-mechanical technique using Papacarie® Group 3: mechanical technique using a bur rotary instrument. Each group was tested using Knoop Micro-hardness tester, and the data were submitted to one way ANOVA and Post-hoc Tukey test. There is a significant difference between Groups 1 and 3, and Groups 2 and 3, p = 0.000. However, there is no significant difference between Groups 1 and 2, p = 1.000. Affected dentin micro-hardness after removal of infected dentin with a bur rotary tool is higher than after use of the papain gel or Papacarie®. Affected dentin micro-hardness after removal of infected dentin with Papacarie® and papain gel give almost the same result.

  13. A decision tree for the management of exposed cervical dentin (ECD) and dentin hypersensitivity (DHS).

    Science.gov (United States)

    Martens, Luc C

    2013-03-01

    Dentin hypersensitivity (DHS) is a problematic clinical entity that may become an increasing clinical problem for dentists to treat as a consequence of patients retaining their teeth throughout life and improved oral hygiene practices. The aim of this review was to develop a decision tree for the management of exposed cervical dentin (ECD) and DHS. A brief PUBMED literature search was performed on dentin hypersensitivity using "MeSH" terms, "review", and "management". In addition, some websites and local guidelines were screened. From this review, it became clear that all dentate patients should routinely be screened for ECD and DHS. In this respect, underdiagnosis of the condition will be avoided and the preventive management can be initiated early. A decision tree process and a flowchart for daily practice were designed which should be started up as soon as a patient present with ECD or suffers from DHS. This approach takes into account the possible improved quality of life of the patient and is further based on a hierarchy of treatment options. In this respect, active management of DHS will usually involve a combination of at-home and in-office therapies. Starting with the use of desensitizing toothpastes is strongly recommended.

  14. Influence of EDC on Dentin-Resin Shear Bond Strength and Demineralized Dentin Thermal Properties

    Directory of Open Access Journals (Sweden)

    Lin Tang

    2016-11-01

    Full Text Available This study aimed to evaluate the bonding strength and thermal properties of demineralized dentin with and without EDC treatment. Sound human molars were randomly divided into seven treatment groups (n = 20: control, 80% ethanol, and five EDC ethanol solutions (0.01–1.0 M. In each group, 16 samples were used for bond strength assessment and 4 samples were used for scanning electron microscopy (SEM analysis. A further 70 intact molars were used to obtain a fine demineralized dentin powder, treated with the same solutions and were evaluated the crosslink degree by ninhydrin test and denaturation temperature (Td by differential scanning calorimetry. EDC-treated specimens (<1.0 M had a higher bond strength, especially 0.3 and 0.5 M group, than the control counterpart. There was a significant drop in bond strength of 1.0 M EDC group. SEM revealed a homogeneous and regular interface under all treatments. EDC treatment significantly increased the demineralized dentin cross-link degree and Td compared with the control and ethanol treatments. The 0.3 and 0.5 M treatments showed the highest cross-link degree and Td. In terms of mechnical and theramal properties consideration, 0.3 and 0.5 M EDC solutions may be favorable for when applied with etch-and-rinse adhesives, but it is still needed further long-term study.

  15. Comparative evaluation of the effect of different bonding agents on the ultramorphology of primary tooth dentin and the resin dentin interface

    OpenAIRE

    Vashisth, Pallavi; Goswami, Mousumi; Mittal, Mudit; Chaudhary, Seema

    2012-01-01

    Aim: To analyze and compare the changes in the ultramorphology of dentin in primary teeth using different bonding agents and to study the resin/dentin interface produced by them. Materials and Methods: Occlusal surfaces of 50 extracted human deciduous teeth were grounded to expose the dentin. The teeth were divided into two groups (A) For viewing surface morphology- 18 teeth divided into four groups: (a) for viewing dentinal morphology (3 teeth), (b) Scotchbond multi-purpose (5 teeth), (...

  16. PENGARUH BERBAGAI KONDITIONER DENTIN (ASAM PHOSPHAT) TERHADAP KEKUATAN TARIK ANTARA ADHESIVE RESIN (HNPM/TEGDMA) DENGAN JARINGAN DENTIN

    OpenAIRE

    Andi Soufyan; B Irawan; G. Gunadi; Ali Nurdin

    2015-01-01

    The aim of this research is to see the effect of various dentin conditioners (phosphoric acid) to the bond strength between resin adhesive HNPM/TEGDMA (2 Hydroxy-3,2-Napthoxy-Propyl Methacrylate/Trietilen Glokol di Methacrylate) and dentin tissue of bovine teeth. Dentin conditioner that was used are phosphoric acid solution 10% 25%, 35% (Group A1, A2, A3). Specimens was divided into 3 groups, each group has 10 specimens. Bond strength test used "Universal Testing Machine" AG 5000 and SHIMADZU...

  17. Influence of Immediate Dentin Sealing on the Shear Bond Strength of Pressed Ceramic Luted to Dentin with Self-Etch Resin Cement

    Directory of Open Access Journals (Sweden)

    Robert Dalby

    2012-01-01

    Full Text Available Objectives. To examine the effect of immediate dentin sealing (IDS, with dentin bonding agents (DBAs applied to freshly cut dentin, on the shear bond strength of etched pressed ceramic luted to dentin with RelyX Unicem (RXU cement. Method. Eighty extracted noncarious third molars were ground flat to expose the occlusal dentin surfaces. The teeth were randomly allocated to five groups (A to E of sixteen teeth each. Groups A to D were allocated a dentin bonding agent (Optibond FL, One Coat Bond, Single Bond, or Go! that was applied to the dentin surface to mimic the clinical procedure of IDS. These specimen groups then had etched glass ceramic discs (Authentic luted to the sealed dentin surface using RXU. Group E (control had etched glass ceramic discs luted to the dentin surface (without a dentin bonding agent using RXU following the manufacturer’s instructions. All specimens were stored for one week in distilled water at room temperature and then shear stressed at a constant cross-head speed of 1 mm per minute until failure. Statistical analysis was performed by ANOVA followed by post hoc Tukey HSD method (0.05 in the SBS between the test groups (A–D or the control (group E. Conclusion. IDS using the dentin bonding agents tested does not statistically (>0.05 affect the shear bond strength of etched pressed ceramic luted to dentin with RXU when compared to the control.

  18. Microbiochemical analysis of carious dentine using Raman and fluorescence spectroscopy

    National Research Council Canada - National Science Library

    Almahdy, A; Downey, F C; Sauro, S; Cook, R J; Sherriff, M; Richards, D; Watson, T F; Banerjee, A; Festy, F

    2012-01-01

    The aim of this study was to evaluate and correlate objectively the microspectroscopically derived biochemical components of sound, infected and affected carious dentine with their microhardness and autofluorescence (AF) characteristics...

  19. Adhesion testing of dentin bonding agents: a review.

    Science.gov (United States)

    Pashley, D H; Sano, H; Ciucchi, B; Yoshiyama, M; Carvalho, R M

    1995-03-01

    Adhesion testing of dentin bonding agents was reviewed starting with the adhesion substrate, dentin, the variables involved in etching, priming and bonding, storage variables and testing variables. Several recent reports attempting to standardize many of these variables were discussed. Recent advances in the development of new bonding systems have resulted in bond strengths on the order of 20-30 MPa. At these high bond strengths, most of the bond failure modes have been cohesive in dentin. As this precludes measurement of interfacial bond strength, new testing methods must be developed. One such new method, a microtensile method, was described along with preliminary results that have been obtained. The last decade has produced major advances in dentin bonding. The next decade should prove to be even more exciting.

  20. Morphological effects of MMPs inhibitors on the dentin bonding

    National Research Council Canada - National Science Library

    Li, He; Li, Tianbo; Li, Xiuying; Zhang, Zhimin; Li, Penglian; Li, Zhenling

    2015-01-01

    Matrix metalloproteinases (MMPs) have been studied extensively, and MMP inhibitors have been used as dental pretreatment agents prior to dentin bonding because they reduce collagen fiber degradation and improve bonding strength...

  1. Innovations for combating dentin hypersensitivity: current state of the art.

    Science.gov (United States)

    Li, Yiming

    2012-06-01

    Dentin hypersensitivity is a common dental complaint, and in severe cases it can impair eating, drinking, and even speaking, thus interfering with the normal daily life of an individual. Throughout years of research, there has been significant advancement in understanding dentin hypersensitivity, and various treatment regimens have been developed for combating the problem. The continued efforts have recently resulted in a novel technology that uses 8% arginine and calcium carbonate for treating dentin hypersensitivity. Formulations of oral care products using this technology--including toothpaste and prophylactic pastes--have demonstrated not only their effectiveness but also their ability to provide instant relief. This paper provides an overview of the etiology of dentin hypersensitivity, the discovery and development of measures for combating the problem, and the available data on the clinical efficacy of products based on 8% arginine and calcium carbonate.

  2. In vivo Dentin Microhardness beneath a Calcium-Phosphate Cement

    Science.gov (United States)

    Bresciani, E.; Wagner, W.C.; Navarro, M.F.L.; Dickens, S.H.; Peters, M.C.

    2010-01-01

    A minimally invasive caries-removal technique preserves potentially repairable, caries-affected dentin. Mineral-releasing cements may promote remineralization of soft residual dentin. This study evaluated the in vivo remineralization capacity of resin-based calcium-phosphate cement (Ca-PO4) used for indirect pulp-capping. Permanent carious and sound teeth indicated for extraction were excavated and restored either with or without the Ca-PO4 base (control), followed by adhesive restoration. Study teeth were extracted after 3 months, followed by sectioning and in vitro microhardness analysis of the cavity floor to 115-µm depth. Caries-affected dentin that received acid conditioning prior to Ca-PO4 basing showed significantly increased Knoop hardness near the cavity floor. The non-etched group presented results similar to those of the non-treated group. Acid etching prior to cement application increased microhardness of residual dentin near the interface after 3 months in situ. PMID:20511564

  3. Untreated Cavitated Dentine Lesions: Impact on Children's Quality of Life

    National Research Council Canada - National Science Library

    Leal, S.C; Bronkhorst, E.M; Fan, M; Frencken, J.E

    2012-01-01

    The aim of the present investigation was to assess the impact of dental caries prevalence and the consequences of untreated cavitated dentine lesions on quality of life of 6- and 7-year-old Brazilian children...

  4. Quantification of residual dentine thickness following crown preparation

    National Research Council Canada - National Science Library

    Davis, Graham R; Tayeb, Rabab A; Seymour, Kevin G; Cherukara, George P

    2012-01-01

    Pulpal response to tooth preparation is a major concern in fixed prosthodontics. Research has suggested that 2mm or more of remaining dentine is critical in protecting the pulp following tooth preparation...

  5. Effect of intracoronal bleaching agents on dentin microhardness.

    Science.gov (United States)

    de Oliveira, Daniel Pinto; Teixeira, Erica Cappelletto Nogueira; Ferraz, Caio Cezar Randi; Teixeira, Fabricio B

    2007-04-01

    The purpose of this in vitro study was to compare the effect of intracoronal bleaching agents associated or unassociated with chlorhexidine gel on dentin microhardness. Sixty human maxillary incisor crowns were divided into six groups, and bleaching agents were sealed into the pulp chambers as follows: sodium perborate + water (SPW), sodium perborate + 2% chlorhexidine gel (SP + CHX), sodium perborate + 30% hydrogen peroxide solution (SP + HP), 37% carbamide peroxide gel (CP), 37% carbamide peroxide gel + 2% chlorhexidine gel (CP+CHX), and water (W). After the bleaching procedure, microhardness testing was carried out on the dentin surface at three different levels: inner, middle, and outer dentin. The greatest reduction in microhardness was observed for the SP + HP group. No differences were observed between the SPW and SP + CHX group. The 2% chlorhexidine gel did not adversely affect dentin microhardness when associated with the tested bleaching agents. CHX might be considered as an antimicrobial vehicle during intracoronal bleaching.

  6. What’s New in Dentine Bonding?: Universal Adhesives.

    Science.gov (United States)

    Trevor Burke, F J; Lawson, Anna; Green, David J B; Mackenzie, Louis

    2017-04-01

    The ability to bond restorations to dentine successfully is central to minimally invasive restorative dentistry. While dentine-bonding agents have gone through a variety of ‘generations’, it is the purpose of this paper to describe the latest dentine-bonding agents, the Universal Bonding Agents. These materials may be considered ‘Universal’ insofar as they may be considered to be capable of being used for direct and indirect dentistry, as well as being suitable for use in whichever etching modality the clinician considers appropriate, namely self-etch, etch and rinse or selective enamel etch. Laboratory investigations and initial clinical studies hold the promise that Universal Bonding Agents are a forward step in the quest for the ultimate bond to tooth substance. Clinical relevance: New Universal Bonding Agents appear to present a promising advance in bonding to dentine.

  7. Role of Alcohol on the Fracture Resistance of Dentin

    Energy Technology Data Exchange (ETDEWEB)

    Nalla, Ravi K.; Kinney, John H.; Tomsia, Antoni P.; Ritchie,Robert O.

    2006-05-01

    Healthy dentin, the mineralized tissue that makes up the bulk of the tooth, is naturally hydrated in vivo; however, it is known that various chemical reagents including acetone and ethanol can induce dehydration and thereby affect its properties. Here, we seek to investigate this in light of the effect alcohol can have on the mechanical properties of dentin, specifically by measuring the stiffness, strength and toughness of dentin in simulated body fluid and scotch whisky. Results indicate that chemical dehydration induced by the whisky has a significant beneficial effect on the elastic modulus, strength and fracture toughness of dentin. Although this makes teeth more resistant to fracture, the change in properties is fully reversible upon rehydration. This effect is considered to be associated with increased cross-linking of the collagen molecules from intermolecular hydrogen-bonding where water is replaced with weaker hydrogen-bond forming solvents such as alcohol.

  8. Principales causas de la morosidad en la jurisdicción laboral

    Directory of Open Access Journals (Sweden)

    Rafael Ospina Morales

    2006-01-01

    Full Text Available El proyecto desarrollado es de gran magnitud e importancia, toda vez que surgen “cascadas de leyes” que al poco tiempo de su vigencia, están siendo modificadas, adicionadas o derogadas, por quienes solucionan todos los problemas de Estado con sus administrados, expidiendo leyes, SINAVERIGUARLAS CAUSAS que han generado la patología social en determinado momento. La Ley debe tener en cuenta el fenómeno social, pero no a la ligera, sino profundizando sobre el origen y causa del mismo. Esto es lo que pregona científicamente la Escuela Constructivista. Con la presente investigación se contribuye a establecer algunas de las causas que generan la morosidad en la jurisdicción laboral.

  9. Doença de Chagas como causa básica de óbito na região sudeste do Brasil: presença de causas contributárias

    Directory of Open Access Journals (Sweden)

    Dalva Marli Valério Wanderley

    1994-02-01

    Full Text Available Estudaram-se os atestados de pessoas falecidas no Estado de São Paulo, Brasil, em 1987, cuja causa básica foi a cardiopatia chagásica, com a finalidade de conhecer a informação adicional que está presente no atestado como "causa contributária". Foram analisadas as informações existentes em 1.308 Declarações de Óbito. As causas contributárias foram identificadas e registradas a partir de uma leitura direta do atestado. Foram identificadas 261 Declarações com causas contributárias (20%, sendo 185 com apenas uma causa registrada e 75 com duas. As seis primeiras causas foram: megas, embolias, doença pulmonar crônica, infecções (exceto doença de Chagas, hipertensão arterial e desnutrição. Analisando a presença das causas contributárias no subgrupo de menores de 50 anos e de 50 anos ou mais, constatou-se uma maior proporção no grupo mais idoso e um perfil diferenciado de causas em cada subgrupo. As causas contributárias não apresentaram associação com sexo e local de residência.

  10. Hyperfibers and vesicles in dentin matrix in dentinogenesis imperfecta (DI) associated with osteogenesis imperfecta (OI).

    Science.gov (United States)

    Waltimo, J

    1994-10-01

    Dentin matrix of deciduous teeth from two patients affected by dentinogenesis imperfecta (DI) associated with types IB and IVB osteogenesis imperfecta (OI) displayed previously undescribed structures in transmission electron microscopic examination. Vesicles were seen in dentin of both patients, and abnormally thick collagen fibers (hyperfibers) were found in dentin of the patient with the rare type IB OI. Both vesicles and hyperfibers were situated in abnormal, atubular areas of dentin. Matrix vesicles, which have normally been identified in mantle dentin only, were abundant in selected areas of the affected dentin, thereby supporting the concept that dentin matrix in OI is elaborated by successive cell generations. The hyperfibers, not previously described in either normal or abnormal human dentin, have possibly been formed by fusion of several collagen fibers. Further ultrastructural studies of dentin in DI with OI may help to clarify the marked clinical variation in teeth of patients affected by OI.

  11. Morphology of the dentin structure of sloths Bradypus tridactylus: a light and scanning electron microscopy investigation.

    Science.gov (United States)

    Santana, L N S; Barbosa, L V M; Teixeira, F B; Costa, A M P; Fernandes, L M P; Lima, R R

    2013-12-01

    The aim of this study was to describe the dentine morphology of sloths (Bradypus tridactylus). The sloth teeth were removed and prepared for light microscopy (LM) and scanning electron microscopy analyses (SEM). LM revealed two patterns of tubular dentins: an outer with dentinary tubules over the all tooth length and one in the inner part with larger diameter and more spaced tubules, when compared to those present in the outer dentine. These findings were confirmed by SEM, which revealed a tubular pattern in the outer dentine like in humans. The inner dentine displayed pared grouped tubules that were characterized as vascular channels. It can be concluded that this sloth species present two types of dentins: an inner dentin (ortodentin) and an outer dentin characterized as a vascular dentin. This suggests a partial evolutive/adaptive process of this dental tissue, as compared to other mammalian species. © 2013 Blackwell Verlag GmbH.

  12. Dentinal Ultrastructure In Osteogenesis Imperfecta and Dentinogenesis Imperfecta

    OpenAIRE

    Harith, N. S. B.

    2013-01-01

    Osteogenesis Imperfecta (OI) associated with Dentinogenesis Imperfecta, type I (DI) is a rare genetic condition, where mutations of COL1A1 and COL1A2 genes result in variations of the collagen α-chains. The collagen fibrils are expected to be abnormally thin. These alterations have been shown to affect the bones, but have not yet been elucidated in the dentinal collagen. Objectives: Evaluation of demineralisation protocols to expose dentinal collagen for permanent and primary teeth and to cha...

  13. Bio-reconstruction of root canal using dentin post

    OpenAIRE

    Navin Mishra; Isha Narang

    2013-01-01

    This case report describes the successful management of complicated crown fracture of left maxillary central incisor (#21) of 23-year-old male using dentin (biological) post made from human tooth. Endodontic treatment was initiated and sectional obturation was done using ProTaper gutta-percha and AH Plus sealer. The coronal space was modified to receive a human dentin post. A two-step procedure comprising direct and indirect technique of post fabrication was done to achieve the accuracy of bi...

  14. Morphological effects of MMPs inhibitors on the dentin bonding.

    Science.gov (United States)

    Li, He; Li, Tianbo; Li, Xiuying; Zhang, Zhimin; Li, Penglian; Li, Zhenling

    2015-01-01

    Matrix metalloproteinases (MMPs) have been studied extensively, and MMP inhibitors have been used as dental pretreatment agents prior to dentin bonding because they reduce collagen fiber degradation and improve bonding strength. However, morphologic characteristics of the collagen network after etching and of the post-adhesive dentin hybrid layers (DHL) after MMP inhibitors pretreatment have not been evaluated. Thus, we investigated demineralized dentin pretreated with chlorhexidine (CHX) and minocycline (MI) in an etch- and -rinse adhesive system with field emission scanning electron microscopy (FESEM) and immuno-gold labeling markers to observe the collagen network and DHL. FESEM revealed after CHX and MI, a demineralized dentin surface and improved collagen network formation, reduced collagen degradation, and distinct gold-labeling signals. Applying adhesive after either MMP inhibitor created a better dentin interface as evidenced by immuno-gold staining, better adhesive penetration, and higher DHL quality. With microtensile bond strength tests (µTBS) we estimated bonding strength using µTBS data. Immediate µTBS was enhanced with MMP inhibitor application to the bonding surface, and the CHX group was significantly different than non-treated etched surfaces, but no significant change was detected in the MI group. Surface micromorphology of the fractured dentin resin restoration showed that the CHX group had a better resin and dentin tube combination. Both MMP inhibitors created uniform resin coverage. Thus, morphologic results and µTBS data suggest that CHX and MI can inhibit MMP activity, improve immediate bonding strength, and enhance dentin bonding stability with an etch- and -rinse adhesive system.

  15. Bonding stability of adhesive systems to eroded dentin

    Directory of Open Access Journals (Sweden)

    Janaina Barros CRUZ

    2015-01-01

    Full Text Available This in vitro study evaluated the immediate and 6 months microshear bond strength (µSBS of different adhesive systems to sound and eroded dentin. Sixty bovine incisors were embedded in acrylic resin and ground to obtain flat buccal dentin surfaces. Specimens were randomly allocated into two groups: sound dentin (immersion in artificial saliva and eroded dentin (erosive challenge following a pH cycling model comprising 4 ×/day Sprite Light® drink for 10 days. Then, specimens were reassigned according to the adhesive system: etch-and-rinse adhesive (Adper Single Bond, two-step self-etch system (Clearfil SE Bond, or one-step self-etch adhesive (Adper Easy One. Polyethylene tubes with an internal diameter of 0.76 mm were placed over pre-treated dentin and filled with resin composite (Z250. Half of the specimens were evaluated by the µSBS test after 24 h, and the other half 6 months later, after water storage at 37°C. Failure mode was evaluated using a stereomicroscope (400×. Data were analyzed by three-way repeated measures analysis of variance and Tukey’s post hoc tests (α = 0.05. After 6 months of water aging, marked reductions in µSBS values were observed, irrespective of the substrate. The µSBS values for eroded dentin were lower than those obtained for sound dentin. No difference in bonding effectiveness was observed among adhesive systems. For all groups, adhesive/mixed failure was observed. In conclusion, eroded dentin compromises the bonding quality of adhesive systems over time.

  16. Mesenchymal Dental Pulp Cells Attenuate Dentin Resorption in Homeostasis

    Science.gov (United States)

    Zheng, Y.; Chen, M.; He, L.; Marão, H.F.; Sun, D.M.; Zhou, J.; Kim, S.G.; Song, S.; Wang, S.L.

    2015-01-01

    Dentin in permanent teeth rarely undergoes resorption in development, homeostasis, or aging, in contrast to bone that undergoes periodic resorption/remodeling. The authors hypothesized that cells in the mesenchymal compartment of dental pulp attenuate osteoclastogenesis. Mononucleated and adherent cells from donor-matched rat dental pulp (dental pulp cells [DPCs]) and alveolar bone (alveolar bone cells [ABCs]) were isolated and separately cocultured with primary rat splenocytes. Primary splenocytes readily aggregated and formed osteoclast-like cells in chemically defined osteoclastogenesis medium with 20 ng/mL of macrophage colony-stimulating factor (M-CSF) and 50 ng/mL of receptor activator of nuclear factor κB ligand (RANKL). Strikingly, DPCs attenuated osteoclastogenesis when cocultured with primary splenocytes, whereas ABCs slightly but significantly promoted osteoclastogenesis. DPCs yielded ~20-fold lower RANKL expression but >2-fold higher osteoprotegerin (OPG) expression than donor-matched ABCs, yielding a RANKL/OPG ratio of 41:1 (ABCs:DPCs). Vitamin D3 significantly promoted RANKL expression in ABCs and OPG in DPCs. In vivo, rat maxillary incisors were atraumatically extracted (without any tooth fractures), followed by retrograde pulpectomy to remove DPCs and immediate replantation into the extraction sockets to allow repopulation of the surgically treated root canal with periodontal and alveolar bone–derived cells. After 8 wk, multiple dentin/root resorption lacunae were present in root dentin with robust RANKL and OPG expression. There were areas of dentin resoprtion alternating with areas of osteodentin formation in root dentin surface in the observed 8 wk. These findings suggest that DPCs of the mesenchymal compartment have an innate ability to attenuate osteoclastogenesis and that this innate ability may be responsible for the absence of dentin resorption in homeostasis. Mesenchymal attenuation of dentin resorption may have implications in internal

  17. Mesenchymal dental pulp cells attenuate dentin resorption in homeostasis.

    Science.gov (United States)

    Zheng, Y; Chen, M; He, L; Marão, H F; Sun, D M; Zhou, J; Kim, S G; Song, S; Wang, S L; Mao, J J

    2015-06-01

    Dentin in permanent teeth rarely undergoes resorption in development, homeostasis, or aging, in contrast to bone that undergoes periodic resorption/remodeling. The authors hypothesized that cells in the mesenchymal compartment of dental pulp attenuate osteoclastogenesis. Mononucleated and adherent cells from donor-matched rat dental pulp (dental pulp cells [DPCs]) and alveolar bone (alveolar bone cells [ABCs]) were isolated and separately cocultured with primary rat splenocytes. Primary splenocytes readily aggregated and formed osteoclast-like cells in chemically defined osteoclastogenesis medium with 20 ng/mL of macrophage colony-stimulating factor (M-CSF) and 50 ng/mL of receptor activator of nuclear factor κB ligand (RANKL). Strikingly, DPCs attenuated osteoclastogenesis when cocultured with primary splenocytes, whereas ABCs slightly but significantly promoted osteoclastogenesis. DPCs yielded ~20-fold lower RANKL expression but >2-fold higher osteoprotegerin (OPG) expression than donor-matched ABCs, yielding a RANKL/OPG ratio of 41:1 (ABCs:DPCs). Vitamin D3 significantly promoted RANKL expression in ABCs and OPG in DPCs. In vivo, rat maxillary incisors were atraumatically extracted (without any tooth fractures), followed by retrograde pulpectomy to remove DPCs and immediate replantation into the extraction sockets to allow repopulation of the surgically treated root canal with periodontal and alveolar bone-derived cells. After 8 wk, multiple dentin/root resorption lacunae were present in root dentin with robust RANKL and OPG expression. There were areas of dentin resoprtion alternating with areas of osteodentin formation in root dentin surface in the observed 8 wk. These findings suggest that DPCs of the mesenchymal compartment have an innate ability to attenuate osteoclastogenesis and that this innate ability may be responsible for the absence of dentin resorption in homeostasis. Mesenchymal attenuation of dentin resorption may have implications in internal

  18. Analysis of primary tooth dentin after indirect pulp capping.

    Science.gov (United States)

    Marchi, Juliana J; Froner, Andrea M; Alves, Hugo L R; Bergmann, Carlos P; Araújo, Fernando B

    2008-01-01

    The purpose of this study was to evaluate the characteristics of primary molar dentin after indirect pulp capping (ICP) by of color, consistency and microhardness analyses. The study design consisted of 3 groups: a test group of 13 primary molars that had been submitted to ICP with either calcium hydroxide or resin-modified glass ionomer cement; a positive control group of 15 sound molars; and a negative control group of 15 molars with deep acute carious lesions. The test group teeth had their restorations and pulp-capping materials removed and their cavity depth measured (mean depth=3-4 mm). In the positive control group, 3- to 4-mm-deep cavities were prepared. In the negative control group, the infected dentin was removed following the same parameters used for dentin excavation in a previous study by the authors. In all groups, the remaining dentin was analyzed according to descriptive standards (consistency and color). Microhardness was performed by a calibrated examiner blinded to the groups. Data were analyzed statistically by 1-way analysis of variance and Tukey's test (P <.01). The dentin of all teeth in the test group became hard. Nine teeth had yellow-clear dentin, and 4 teeth had dark-brown dentin. Microhardness means (+/-SD) were: test group=40.81 (+/-16.28) KHN (Knoop hardness number); positive control group=62.73 (+/-11.24) KHN; and negative control group=19.15 (+/-6.99) KHN. Microhardness assessment showed no statistically significant differences (P <.01) among the groups. This study's results suggest a mineral gain by the affected dentin after IPC, regardless of the protective base material.

  19. As causas externas no Brasil no ano 2000: comparando a mortalidade e a morbidade

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    Gawryszewski Vilma Pinheiro

    2004-01-01

    Full Text Available Desde o início da década de 80, as causas externas representam a segunda causa de morte no Brasil. Também determinam crescente demanda aos serviços de saúde. O objetivo do presente trabalho é analisar a morbi-mortalidade por causas externas no Brasil. O material do estudo é composto pelas 118.367 mortes e 652.249 internações hospitalares por causas externas ocorridas no Brasil no ano 2000. Os dados são provenientes do Sistema de Informações de Mortalidade e Sistema de Informações Hospitalares. Entre os resultados destaca-se que o coeficiente de mortalidade por causas externas foi 69,7/100 mil (119,0/100 mil para os homens e 21,8/100 mil para as mulheres. Os homicídios lideraram as causas de morte (38,3% do total, com coeficiente alto, 26,7/100 mil e as quedas lideram as internações (42,8% do total. Os traumas e lesões relacionados ao transporte terrestre são importantes tanto na morbidade quanto na mortalidade. As fraturas representaram 42,6% das hospitalizações, mais freqüentes em membros superiores e inferiores. Aponta-se que os programas de prevenção devem ter impacto tanto na mortalidade quanto na morbidade, com destaque para os homicídios, transporte e quedas.

  20. As causas externas no Brasil no ano 2000: comparando a mortalidade e a morbidade

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    Vilma Pinheiro Gawryszewski

    2004-08-01

    Full Text Available Desde o início da década de 80, as causas externas representam a segunda causa de morte no Brasil. Também determinam crescente demanda aos serviços de saúde. O objetivo do presente trabalho é analisar a morbi-mortalidade por causas externas no Brasil. O material do estudo é composto pelas 118.367 mortes e 652.249 internações hospitalares por causas externas ocorridas no Brasil no ano 2000. Os dados são provenientes do Sistema de Informações de Mortalidade e Sistema de Informações Hospitalares. Entre os resultados destaca-se que o coeficiente de mortalidade por causas externas foi 69,7/100 mil (119,0/100 mil para os homens e 21,8/100 mil para as mulheres. Os homicídios lideraram as causas de morte (38,3% do total, com coeficiente alto, 26,7/100 mil e as quedas lideram as internações (42,8% do total. Os traumas e lesões relacionados ao transporte terrestre são importantes tanto na morbidade quanto na mortalidade. As fraturas representaram 42,6% das hospitalizações, mais freqüentes em membros superiores e inferiores. Aponta-se que os programas de prevenção devem ter impacto tanto na mortalidade quanto na morbidade, com destaque para os homicídios, transporte e quedas.

  1. Influencia da causa de morte no peso corporal e dos orgaos internos em autopsias perinatais

    OpenAIRE

    Correa,Rosana Rosa Miranda; Rocha,Laura Penna; Petrini,Caetano Galvao; Teixeira,Vicente de Paula Antunes; Castro,Eumenia Costa da Cunha

    2014-01-01

    OBJETIVO: Avaliar as variações do peso corporal e dos órgãos internos de crianças autopsiadas no período perinatal e sua relação com a causa de morte. MÉTODOS: Foram incluídos 153 casos de autópsias perinatais realizadas em um hospital universitário do Sudeste do Brasil. Informações sobre causa de morte perinatal, data da autópsia, idade gestacional, peso perinatal e dos órgãos foram recuperadas dos prot...

  2. Causa formal: su inmanencia y eternidad en Aristóteles

    OpenAIRE

    Di Camillo, Silvana Gabriela

    2013-01-01

    Las razones que conducen a Aristóteles a criticar las posiciones de su maestro importan para entender y apreciar sus propias posiciones alternativas. En este trabajo me propongo analizar su propuesta de la causa formal como un principio interno y, a la vez, eterno, que puede comprenderse mejor si la consideramos como un intento de solución de las dificultades que presentan las Ideas como causas. En el contexto del libro A de la Metafísica, en el que Aristóteles examina las tesis de sus pre...

  3. La estrategia de marketing con causa: Factores determinantes de su éxito

    OpenAIRE

    Isabel Buil; Iguácel Melero; Teresa Montaner

    2012-01-01

    Las iniciativas de marketing con causa se han convertido en una estrategia frecuente para mejorar la imagen de las compañías y aumentar las ventas, atrayendo al consumidor a través de la colaboración con fines sociales. Este estudio analiza los factores que influyen en el éxito de esta estrategia. Los resultados muestran que las empresas deberían elegir causas vinculadas con su actividad principal y con las que el consumidor se sienta implicado. Además, es importante que el consumidor atribuy...

  4. Prevención de incendios provocados por causas eléctricas en centros comerciales

    OpenAIRE

    Ñauta Chuisaca, Pedro Santiago; Ulloa Duran, Marco Javier

    2009-01-01

    A lo largo del tiempo se ha venido dando muchos incendios en la ciudad y en todo el país. Estos incendios son debidos a diversas causas, siendo las más señaladas por parte de la población y el personal que mitiga e investiga los mismos las de origen eléctrico, principalmente los cortocircuitos. Por tal razón se ha visto necesario establecer un marco de referencia en donde indique cuales son las causas eléctricas que pueden provocar incendios, para luego indicar las protecciones y medidas nece...

  5. IDEAS SOBRE LAS CAUSAS DE LA OBESIDAD EN ESTUDIANTES UNIVERSITARIOS MEXICANOS Y ESPAÑOLES

    OpenAIRE

    Rigoberto León Sánchez; Blanca Elizabeth Jiménez Cruz; Asunción López Manjón; Kirareset Barrera García

    2014-01-01

    Diversos estudios han mostrado que los profesionales de la salud estigmatizan la obesidad, incluso aquellos que dedican su labor a la atención del paciente obeso. Es posible que dichas creencias negativas tengan que ver con la atribución de las causas de la obesidad, es decir, si se supone que la persona obesa tiene o no responsabilidad sobre su padecimiento. El propósito del presente trabajo fue examinar las creencias sobre las causas de la obesidad de dos grupos de estudiantes universitario...

  6. Analytical method to estimate resin cement diffusion into dentin

    Science.gov (United States)

    de Oliveira Ferraz, Larissa Cristina; Ubaldini, Adriana Lemos Mori; de Oliveira, Bruna Medeiros Bertol; Neto, Antonio Medina; Sato, Fracielle; Baesso, Mauro Luciano; Pascotto, Renata Corrêa

    2016-05-01

    This study analyzed the diffusion of two resin luting agents (resin cements) into dentin, with the aim of presenting an analytical method for estimating the thickness of the diffusion zone. Class V cavities were prepared in the buccal and lingual surfaces of molars (n=9). Indirect composite inlays were luted into the cavities with either a self-adhesive or a self-etch resin cement. The teeth were sectioned bucco-lingually and the cement-dentin interface was analyzed by using micro-Raman spectroscopy (MRS) and scanning electron microscopy. Evolution of peak intensities of the Raman bands, collected from the functional groups corresponding to the resin monomer (C-O-C, 1113 cm-1) present in the cements, and the mineral content (P-O, 961 cm-1) in dentin were sigmoid shaped functions. A Boltzmann function (BF) was then fitted to the peaks encountered at 1113 cm-1 to estimate the resin cement diffusion into dentin. The BF identified a resin cement-dentin diffusion zone of 1.8±0.4 μm for the self-adhesive cement and 2.5±0.3 μm for the self-etch cement. This analysis allowed the authors to estimate the diffusion of the resin cements into the dentin. Fitting the MRS data to the BF contributed to and is relevant for future studies of the adhesive interface.

  7. Distinct photopolymerization efficacy on dentin of self-etch adhesives.

    Science.gov (United States)

    Zhang, Y; Wang, Y

    2012-08-01

    The effect of application mode on polymerization effectiveness of self-etch adhesives with different pHs has rarely been studied. We applied 2 self-etch adhesives-Adper Prompt L-Pop (APLP, pH ~ 0.8) and Adper Easy-Bond (AEB, pH ~ 2.5)-to dentin with or without agitation (dynamic or static application), to investigate photopolymerization efficacy on dentin, and to understand the role of chemical interaction/reaction between adhesives and dentin. Micro-Raman spectra and imaging were acquired across the dentin/adhesive (D/A) interface. The degree of conversion (DC) of each adhesive as a function of position was calculated. SEM-EDS was used to obtain the elemental distribution along the interface. Photopolymerization efficacies of the two self-etch adhesives on dentin were apparently different. APLP exhibited decreasing DCs as the distance from the D/A interface became greater for both application modes, while the DCs for the dynamic mode were much higher than those for the static mode. As for AEB, the DCs remained almost constant across the adhesive layer and showed no significant difference between two modes. Raman spectral analysis disclosed that the chemical interaction between dentin and adhesives was responsible for the observations. We also verified this by tracking the distribution of the elements Ca and P in the adhesive layers.

  8. The characterization of dentin defects produced by air polishing.

    Science.gov (United States)

    Tada, Kazuhiro; Wiroj, Suphasiriroj; Inatomi, Michitomo; Sato, Soh

    2012-01-01

    The objective of this study is to characterize the defects in the dentin surface after air polishing for three types of polishing powders and five different nozzle distances. Human teeth were embedded in acrylic resin and then polished until the dentin surface became exposed. The nozzle of the polisher was fixed at a specified distance (2, 3, 4, 5, or 6 mm) and orientation (45°) with respect to the dentin surface. The three powders were CLASSIC (NaHCO(3), 65 μm diameter), PERIO (glycine, 25 μm diameter), and SOFT (glycine, 65 μm diameter). With respect to nozzle distance, we find a significant difference in the mean defect depth only at 6 mm. The spray distance of 6 mm produced the shallowest defect depths. This variable had no effect on the defect volume. SOFT powder had significantly less depths and volumes of defects than the other two powders. The contact angle of the dentin increased significantly in all polishing tests, compared to an unpolished dentin surface (control). We find that spray distance of 6 mm from the nozzle of the polisher and orienting on 45° angle produced less dentin surface defects than any other distance in all powder systems used. At this distance, SOFT powder produced statistically significant smaller depth and volume defects than the other two powder groups.

  9. Methods for Biomimetic Remineralization of Human Dentine: A Systematic Review

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    Chris Ying Cao

    2015-03-01

    Full Text Available This study aimed to review the laboratory methods on biomimetic remineralization of demineralized human dentine. A systematic search of the publications in the PubMed, TRIP, and Web of Science databases was performed. Titles and abstracts of initially identified publications were screened. Clinical trials, reviews, non-English articles, resin-dentine interface studies, hybrid layer studies, hybrid scaffolds studies, and irrelevant studies were excluded. The remaining papers were retrieved with full texts. Manual screening was conducted on the bibliographies of remaining papers to identify relevant articles. A total of 716 studies were found, and 690 were excluded after initial screening. Two articles were identified from the bibliographies of the remaining papers. After retrieving the full text, 23 were included in this systematic review. Sixteen studies used analogues to mimic the functions of non-collagenous proteins in biomineralization of dentine, and four studies used bioactive materials to induce apatite formation on demineralized dentine surface. One study used zinc as a bioactive element, one study used polydopamine, and another study constructed an agarose hydrogel system for biomimetic mineralization of dentine. Many studies reported success in biomimetic mineralization of dentine, including the use of non-collagenous protein analogues, bioactive materials, or elements and agarose hydrogel system.

  10. Bond strength of resin modified glass ionomer cement to primary dentin after cutting with different bur types and dentin conditioning

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    Rebeca Di Nicoló

    2007-10-01

    Full Text Available The aim of this in vitro study was to evaluate the effect of different bur types and acid etching protocols on the shear bond strength (SBS of a resin modified glass ionomer cement (RM-GIC to primary dentin. Forty-eight clinically sound human primary molars were selected and randomly assigned to four groups (n=12. In G1, the lingual surface of the teeth was cut with a carbide bur until a 2.0-mm-diameter dentin area was exposed, followed by the application of RM-GIC (Vitremer - 3M/ESPE prepared according to the manufacturer's instructions. The specimens of G2, received the same treatment of G1, however the dentin was conditioned with phosphoric acid. In groups G3 and G4 the same procedures of G1 and G2 were conducted respectively, nevertheless dentin cutting was made with a diamond bur. The specimens were stored in distilled water at 37ºC for 24h, and then tested in a universal testing machine. SBS. data were submitted to 2-way ANOVA (= 5% and indicated that SBS values of RM-GIC bonded to primary dentin cut with different burs were not statistically different, but the specimens that were conditioned with phosphoric acid presented SBS values significantly higher that those without conditioning. To observe micromorphologic characteristics of the effects of dentin surface cut by diamond or carbide rotary instruments and conditioners treatment, some specimens were examined by scanning electron microscopy. Smear layer was present in all specimens regardless of the type of rotary instrument used for dentin cutting, and specimens etched with phosphoric acid presented more effective removal of smear layer. It was concluded that SBS of a RM-GIC to primary dentin was affected by the acid conditioning but the bur type had no influence.

  11. [Study of the fine structure of human deciduous dentin with dentinogenesis imperfecta, with special reference to the mantle dentin].

    Science.gov (United States)

    Morikawa, S; Yamasaki, A; Saito, T; Mita, A; Kubota, R; Tanabe, T

    1990-01-01

    A lower deciduous incioer exhibiting dentinogenesis imperfecta (D.I) obtained from a 6-year-old boy with osteogenesis imperfecta (Shields' Type I) was examined by means of light microscopy (LM), scanning electron microscopy (SEM), and X-ray microanalysis (XMA). With LM, the dentin displayed a sparse and irregular tubular pattern near the dentino-enamel junction (DEJ) and only few or no tubular structures in the area corresponding to the circumpulpal dentin. Between these two areas, cleft-like structures were characteristically noted. Structural irregularities in the dentinal tubules were also shown with SEM observation. XMA demonstrated that the distribution of both Ca and P in the dentin of DI teeth was apparently lower than that in the normal deciduous incisor used as a control. Specifically, an area along EDJ at a distance of 25-35 microns, corresponding to the mantle dentin, revealed extremely low or no distribution of the both elements. From the present observation, it is suggested that the generic disorder mainly involved in the primary odontoblasts and consequently results in the disturbance of calcification, especially that mediated by the matrix vesicles, and shortening of the cell life. After the death of these cells, the cells originate in, from the undifferentiated pulp cells may participate in the deposition of another irregular dentin.

  12. Proanthocyanidins-Loaded Nanoparticles Enhance Dentin Degradation Resistance.

    Science.gov (United States)

    Fawzy, A S; Priyadarshini, B M; Selvan, S T; Lu, T B; Neo, J

    2017-07-01

    Previous studies reported that grapeseed extract (GSE), which is rich in proanthocyanidins (PAs), improves the biodegradation resistance of demineralized dentin. This study aimed to investigate the effect of a new GSE delivery strategy to demineralized dentin through loading into biodegradable polymer poly-[lactic-co-glycolic acid] (PLGA) nanoparticles on the biodegradation resistance in terms of structural stability and surface/bulk mechanical and biochemical properties with storage time in collagenase-containing solutions. GSE-loaded nanoparticles were synthetized by nanoprecipitation at PLGA/GSE (w/w) ratios of 100:75, 100:50, and 100:25 and characterized for their morphological/structural features, physicochemical characteristics, and drug loading, entrapment, and release. Nanoparticle suspensions in distilled water (12.5% w/v) were applied (1 min) to demineralized dentin specimens by simulating pulpal pressure. The nanoparticle delivery was investigated by scanning electron microscopy (SEM)/transmission electron microscopy (TEM), and the GSE release from the delivered nanoparticles was further characterized. The variations in surface and bulk mechanical properties were characterized in terms of reduced elastic-modulus, hardness, nanoindentation testing, and apparent elastic-modulus with a storage time up to 3 mo. Hydroxyproline release with exposure to collagenase up to 7 d was estimated. An etch-and-rinse dentin adhesive was applied to investigate the morphology of the resin-dentin interface after nanoparticle delivery. Treatment with the GSE-loaded nanoparticles enhanced the collagen fibril structural resistance, reflected from the TEM investigation, and improved the biomechanical and biochemical stability of demineralized dentin. Nanoparticles having PLGA/GSE of 100:75 (w/w) showed the highest cumulative GSE release and were associated with the best improvement in biodegradation resistance. TEM/SEM showed the ability of the nanoparticles to infiltrate

  13. GRAMMATICALIZATION IN SYNCHRONY: THE CASE OF THE CONNECTOR ‘POR CAUSA QUE’

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    Fabrício da Silva Amorim

    2013-12-01

    Full Text Available This article aims at presenting grammaticalization synchronic tracks of the connector por causa que (“by cause that”, from applying the principles designed by Hopper (1991. Moreover, this paper confirms that Hopper (1991 provides suitable principles to investigate processes of gramaticalization under a synchronic perspective.

  14. Hipótesis actuales relacionadas con la sensibilidad dentinal

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    Andrés Pérez Ruiz

    1999-08-01

    Full Text Available Se hace una revisión sobre las hipótesis actuales concernientes a la sensibilidad dentinal, centrando el análisis en las teorías acerca de la presencia de nervios en la dentina, la transmisión del impulso nervioso mediante el odontoblasto y el movimiento de fluidos dentro de la dentina. Por ser la explicación de la sensibilidad de la dentina uno de los más complejos problemas de la fisiología y la histología del diente, se exponen los hechos morfológicos y funcionales que apoyan la validez de los mecanismos mencionados. Se concluye que aunque la teoría hidrodinámica tiene una sólida base experimental y es la de mayor aceptación en la actualidad, pudieran estar involucrados en la génesis del dolor dentinal más de una de estas explicaciones probables.A review of the present hypotheses of dentinal sensitivity was carried out. The analysis was centered on the theories of the existance of nerves in dentin, the transfer of nervous impulse through odontoblast and the fluid flow in the dentin. Since the explanation of dentin sensitivity is one of the most complex problems of dental physiology and histology; the morphological and functional aspects that support the validity of the mentioned mechanisms are stated. It is concluded that although the hydrodynamic theory has a sound experimental basis and is widely accepted at present, more than one of these likely theories could be involved in the genesis of dentinal pain.

  15. Bond durability of self-adhesive composite cements to dentine.

    Science.gov (United States)

    Suyama, Yuji; de Munck, Jan; Cardoso, Marcio Vivan; Yamada, Toshimoto; Van Meerbeek, Bart

    2013-10-01

    Clinically, the most easy-to-use composite cements are the so-called self-adhesive composite cements (SAC's). Hardly any data is however today available on the long-term bonding effectiveness of such luting composites. The purpose of this study was to evaluate the bond durability of different composite cements used to lute feldspathic ceramic blocks onto dentine. Four SAC's (Clearfil SA Cement, Kuraray; G-CEM, GC; SmartCem2, Dentsply; Unicem 3M ESPE), one 'self-etch' (Clearfil Esthetic Cement, Kuraray) and one 'etch-and-rinse' (Variolink ll, Ivoclar-Vivadent) multi-step composite cement were used to lute feldspathic ceramic blocks (Vita Mark II, Vita) onto dentine surfaces. Teeth were distributed randomly in 24 experimental groups according to two different surface-preparation techniques ('SMEAR-COVERED' versus 'SMEAR-FREE') and storage conditions ('IMMEDIATE' versus 'AGED'). Failure patterns were evaluated with a stereomicroscope, and afterwards imaged using Feg-SEM. Two additional specimens were processed for cement-dentine interfacial analysis using TEM. A linear mixed effects statistical model revealed significant differences for the variables 'composite cement', 'surface preparation' and 'ageing'. All self-adhesive composite cements, except Unicem (3M ESPE), did bond less favourably to fractured dentine. TEM revealed an ultra-structurally different interaction of the composite cements with 'SMEAR-COVERED' and 'SMEAR-FREE' dentine. All SAC's suffered most when luted to 'SMEAR-FREE' (fractured) dentine, fortunately of no clinical relevance and most likely due to enhanced water sorption through the open tubules. When luted to 'SMEAR-COVERED' dentine, all SACs appeared equally effective and durable as the 'etch-and-rinse' and 'self-etch' multi-step composite cements. Solely the SAC SmartCem2 (Dentsply) appeared clearly less favourable and consistent. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Bond durability of contemporary adhesive systems to pulp chamber dentin

    Science.gov (United States)

    Ayar, Muhammet Kerim

    2015-01-01

    Abstract Objective: The purpose of this study was to evaluate long-term bond strengths of dentin adhesive systems, which include one-step self-etch adhesive systems (Optibond All-in-one, Kerr; Adper Prompt L-POP, 3 M ESPE), a three-step etch-and-rinse adhesive (Optibond FL, Kerr) and two-step self-etch adhesive (AdheSE Bond, Ivoclar), applied to pulp chamber dentin surfaces after 12-month water storage by using microtensile bond strength (µTBS) test. Materials and methods: Dentin adhesive systems were applied to unprepared pulp chamber dentin surfaces according to manufacturer’s directions, respectively (n = 5). After applying adhesive systems, composite buildups were done incrementally. Bond strengths to pulp chamber dentin surfaces were determined using µTBS test after water storage for 24 h and 12 month. Kruskal–Wallis analysis and Mann–Whitney U-test for pairwise comparisons were used to determine statistical differences in µTBS between the groups at a significance level of 5%. Results: There were no significant differences in µTBS between storage periods for tested adhesives regardless adhesive class. Conclusion: Bond durability of tested adhesive systems, including one-bottle self-etch adhesives with pulp chamber dentin surfaces, may be considered stable after 12-month water storage. Therefore, one-step self-etch, also called “user-friendly” adhesives may perform and traditional three-step etch-and-rinse adhesives in the long-term when used for bonding to pulp chamber dentin surfaces. PMID:28642905

  17. Influence of handpiece maintenance sprays on resin bonding to dentin.

    Science.gov (United States)

    Sugawara, Toyotarou; Kameyama, Atsushi; Haruyama, Akiko; Oishi, Takumi; Kukidome, Nobuyuki; Takase, Yasuaki; Tsunoda, Masatake

    2010-01-01

    To investigate the influence of maintenance spray on resin bonding to dentin. The crown of extracted, caries-free human molars was transversally sectioned with a model trimmer to prepare the dentin surfaces from mid-coronal sound dentin, and then uniformly abraded with #600 silicon carbide paper. The dentin surfaces were randomly divided into three groups: oil-free spray group where maintenance cleaner for air bearing handpieces was sprayed onto the dentin surface for 1 s and rinsed with water spray for 30 s; oil-containing spray group where maintenance cleaner for micro motor handpieces was sprayed onto the dentin surface for 1 s and rinsed with water spray for 30 s; and control group where the surface was rinsed with water spray for 30 s and then air-dried. These surfaces were then bonded with Clearfil SE Bond (Kuraray Medical), and resin composite (Clearfil AP-X, Kuraray Medical) build-up crowns were incrementally constructed on the bonded surfaces. After storage for 24 h in 37°C water, the bonded teeth were sectioned into hour-glass shaped slices (0.7-mm thick) perpendicular to the bonded surfaces. The specimens were then subjected to microtensile bond strength (μTBS) testing at a crosshead speed of 1.0 mm/min. Data were analyzed with one-way ANOVA and the Tukey-Kramer test. Maintenance spray-contaminated specimens (oil-free and oil-containing spray groups) showed significantly lower μTBS than control specimens (P contaminated groups (P > 0.05). Maintenance spray significantly reduces the bond strength of Clearfil SE Bond to dentin.

  18. Sealing Occlusal Dentin Caries in Permanent Molars

    DEFF Research Database (Denmark)

    Qvist, Vibeke; Borum, Mette Kit; Møller, Kirsten Dynes

    2017-01-01

    The purpose of this study was to investigate the possibility of postponing restorative intervention of manifest occlusal caries in young, permanent dentition by non-invasive sealing. This RCT-designed study included 521 occlusal lesions in 521 patients aged 6 to 17 y. Based on clinical and radiog......The purpose of this study was to investigate the possibility of postponing restorative intervention of manifest occlusal caries in young, permanent dentition by non-invasive sealing. This RCT-designed study included 521 occlusal lesions in 521 patients aged 6 to 17 y. Based on clinical...... longevity of sealings and restorations until retreatments, and 3) compare effectiveness of sealings and restorations to halt caries progression in sealed lesions and beneath restorations. Furthermore, we aimed to identify factors influencing longevity and the effectiveness of sealings and restorations.......001). The median survival time for sealings not replaced by restorations was 7.3 y (CI, 6.4 y to NA). Survival of sealings was increased in patients with low caries risk and/or excellent oral hygiene, second molars compared with first molars, and lesions not extending the middle one-third of the dentin. Survival...

  19. Innovative Approaches to Regenerate Enamel and Dentin

    Directory of Open Access Journals (Sweden)

    Xanthippi Chatzistavrou

    2012-01-01

    Full Text Available The process of tooth mineralization and the role of molecular control of cellular behavior during embryonic tooth development have attracted much attention the last few years. The knowledge gained from the research in these fields has improved the general understanding about the formation of dental tissues and the entire tooth and set the basis for teeth regeneration. Tissue engineering using scaffold and cell aggregate methods has been considered to produce bioengineered dental tissues, while dental stem/progenitor cells, which can differentiate into dental cell lineages, have been also introduced into the field of tooth mineralization and regeneration. Some of the main strategies for making enamel, dentin, and complex tooth-like structures are presented in this paper. However, there are still significant barriers that obstruct such strategies to move into the regular clinic practice, and these should be overcome in order to have the regenerative dentistry as the important mean that can treat the consequences of tooth-related diseases.

  20. Adhesive strength of self-adhesive resins to lithium disilicate ceramic and dentin: effect of dentin chelating agents.

    Science.gov (United States)

    Saker, Samah; Alnazzawi, Ahmad; Özcan, Mutlu

    2016-01-01

    The aim of this study was to test the effect of different chelating agents on microtensile bond strength (MTBS) of self-adhesive resin cements to dentin. The occlusal surfaces of extracted human mandibular molars (N = 80) were cut horizontally to expose sound dentin. The teeth were randomly divided into four groups (n = 20 per group) and dentin surfaces were conditioned according to one of the following methods: group C: no treatment (control group); group CH: 0.2 % chitosan; group E: 17 % ethylene diamine tetra acetic acid (EDTA) and group P: 25 % polyacrylic acid (PAA). Lithium disilicate glass ceramic (e.max CAD) blocks were cemented to conditioned dentin surfaces with self-adhesive cements (RelyX Unicem or Clearfil SA) and photo-polymerized. Specimens were stored in distilled water at 37 °C for 24 h and thermocycled for 6,000 times. The beams were obtained from bonded ceramic-cement-tooth assemblies and were subjected to the MTBS test (1 mm/min). Failure types were analyzed and selected beams were examined under scanning electron microscope. Data (MPa) were analyzed using two-way ANOVA and Tukey's test (P type significantly affected the MTBS results (P dentin chelating agents (P = 0.785). Interaction terms were not significant (P = 0.114). Control group with no dentin conditioning presented significantly lower results with both cements (RelyX Unicem: 8.1 ± 1.9(a), Clearfil SA: 8 ± 1.6(a)) than those of conditioned groups (19.3 ± 4.2(b)-24.5 ± 5.2(b)) (P types were predominantly adhesive in all groups. Chitosan (2 %), EDTA (17 %) or PAA (25 %) could all be used as dentin chelating agents in conjunction with self-adhesive resin cements tested.

  1. Adhesive performance of dentin bonding agents applied in vivo and in vitro. Effect of intrapulpal pressure and dentin depth.

    Science.gov (United States)

    Hebling, Josimeri; Castro, Fabrício L A; Costa, Carlos A S

    2007-11-01

    The purpose of this study was to evaluate the influence of intrapulpal pressure and dentin depth on bond strengths of an etch-and-rinse and a self-etching bonding agent to dentin in vitro and in vivo. Twenty-four pairs of premolars were randomly divided into four groups (n = 6) according to the dentin bonding agent, Single Bond and Clearfil SE Bond, and intrapulpal pressure, null or positive. Each tooth of the pair was further designated to be treated in vivo or in vitro. The intrapulpal pressure was controlled in vivo by the delivery of local anesthetics containing or not a vasoconstrictor, while in vitro, it was achieved by keeping the teeth under hydrostatic pressure. Class I cavities were prepared and the dentin bonding agents were applied followed by incremental resin restoration. For the teeth treated in vitro, the same restorative procedures were performed after a 6 month-storage period. Beams with 1 mm(2) cross-sectional area were prepared and microtensile tested. Clearfil SE Bond was not influenced by any of the variables of the study, while bond strengths produced in vitro were significantly higher for Single Bond. Overall, lower bond strengths were produced in deep dentin, which reached statistical significance when Single Bond was applied under physiological or simulated intrapulpal pressure. In conclusion, in vitro bonding may overestimate the immediate adhesive performance of more technique-sensitive dentin bonding systems. The impact of intrapulpal pressure on bond strength seems to be more adhesive dependent than dentin morphological characteristics related to depth.

  2. Mutant DLX 3 disrupts odontoblast polarization and dentin formation

    Science.gov (United States)

    Choi, S.J.; Song, I.S.; Feng, J.Q.; Gao, T.; Haruyama, N.; Gautam, P.; Robey, P.G.; Hart, Thomas C.

    2010-01-01

    Tricho-dento-osseous (TDO) syndrome is an autosomal dominant disorder characterized by abnormalities in the thickness and density of bones and teeth. A 4-bp deletion mutation in the Distal-Less 3 (DLX3) gene is etiologic for most cases of TDO. To investigate the in vivo role of mutant DLX3 (MT-DLX3) on dentin development, we generated transgenic (TG) mice expressing MT-DLX3 driven by a mouse 2.3 Col1A1 promoter. Dentin defects were radiographically evident in all teeth and the size of the nonmineralized pulp was enlarged in TG mice, consistent with clinical characteristics in patients with TDO. High-resolution radiography, microcomputed tomography, and SEM revealed a reduced zone of mineralized dentin with anomalies in the number and organization of dentinal tubules in MT-DLX3 TG mice. Histological and immunohistochemical studies demonstrated that the decreased dentin was accompanied by altered odontoblast cytology that included disruption of odontoblast polarization and reduced numbers of odontoblasts. TUNEL assays indicated enhanced odontoblast apoptosis. Expression levels of the apoptotic marker caspase-3 were increased in odontoblasts in TG mice as well as in odontoblastic-like MDPC-23 cells transfected with MT-DLX3 cDNA. Expression of Runx2, Wnt 10A, and TBC1D19 colocalized with DLX3 expression in odontoblasts, and MT-DLX3 significantly reduced expression of all three genes. TBC1D19 functions in cell polarity and decreased TBC1D19 expression may contribute to the observed disruption of odontoblast polarity and apoptosis. These data indicate that MT-DLX3 acts to disrupt odontoblast cytodifferentiation leading to odontoblast apoptosis, and aberrations of dentin tubule formation and dentin matrix production, resulting in decreased dentin and taurodontism. In summary, this TG model demonstrates that MT-DLX3 has differential effects on matrix production and mineralization in dentin and bone and provides a novel tool for the investigation of odontoblast biology

  3. Quantification of residual dentine thickness following crown preparation.

    Science.gov (United States)

    Davis, Graham R; Tayeb, Rabab A; Seymour, Kevin G; Cherukara, George P

    2012-07-01

    Pulpal response to tooth preparation is a major concern in fixed prosthodontics. Research has suggested that 2mm or more of remaining dentine is critical in protecting the pulp following tooth preparation. However, clinicians have no means of knowing dentine thickness either before or after preparation and therefore lack feedback about this important aspect of preparation quality. The aim of this project was to develop a method for measuring local dentine thickness following tooth preparation for metal ceramic crowns, in vitro, which could be used as a tool to evaluate preparation technique and instrumentation. Microtomography (XMT or micro-CT) scans were taken of extracted teeth before and after crown preparation. Local dentine thickness was defined for every voxel within the 3D tooth image as the sum of distances from that voxel to the pulp and to the anatomical surface. The method also allows the thickness of material removed to be quantified. Three-dimensional colour-coded maps of dentine thickness were generated, and the distributions of dentine thickness throughout the teeth were analysed. This was tested by a single operator on sixteen extracted upper central incisors. This method enabled clear visualisation and analysis of residual dentine thickness. In the trial, it revealed consistent over-prepared regions along the labial proximal line angles which, in a clinical case, could affect subsequent tooth and restoration longevity. All but one of the prepared teeth had regions with a residual dentine thickness of less than 1.5mm, in 6 it was less than 1.0mm and in 3 of these it was less than 0.5mm. Although ex vivo, this method can be used as a research tool to look for patterns of over- or under-preparation, leading to possible modification of technique, instrumentation and, or crown design. It is not currently possible for clinicians to know the thickness of residual dentine following crown preparation, a key factor in long term outcome. The described method

  4. X-ray microanalysis of dentin: a review

    Energy Technology Data Exchange (ETDEWEB)

    Hals, E.; Tveit, A.B.; Totdal, B.

    1988-03-01

    The aim of this review was to present a condensed summary of the literature on X-ray microanalysis of dentin, including both energy-dispersive (EDS) and wavelength-dispersive (WDS) analysis. Estimations of concentrations by XMA of dentin should be regarded as semiquantitative values. The Ca level in rat odontoblasts was elevated in the secreting end of the cell body. In predentin Ca accumulated at a concentration of 2% that of mineralized dentin. In coronal dentin the peritubular areas were hypermineralized (Ca, P, Mg). Primary caries lesions showed a decrease of Ca, P, Mg and Cl, and usually an increase of S and Zn. The mineralized surface often present contained especially high concentrations of F and K. Considerable uptake of various ions in cavity walls exposed to filling materials was assessed: from silver amalgam, Zn and Sn, from silicate cement and glassionomer cement F, Al and Zn, and from zinc oxide-eugenol cement, Zn. The highest F concentrations following topical application were found with solutions of TiF4 and with the varnishes Duraphat and Fluor Protector. Dentin wall lesions adjacent to amalgam fillings exhibited considerably reduced Ca and P values, but concomitantly considerable amounts of Zn and Sn, that explained the increased radiopacity seen in some microradiographs. 84 references.

  5. The fracture properties and toughening mechanisms of bone and dentin

    Science.gov (United States)

    Koester, Kurt John

    The mechanical properties of bone and dentin and in particular their fracture properties, are the subject of intense research. The relevance of these properties is increasing as our population ages and fracture incidence impacts the lives of a greater portion of the population. A robust framework is needed to understand the fracture properties of bone and dentin to guide researchers as they attempt to characterize the effects of aging, disease, and pharmaceutical treatments on the properties of these mineralized tissues. In the present work, this framework is provided and applied to human bone, human dentin, and animal bone. In situ electron microscopy was also used to identify the salient toughening mechanisms in bone and dentin. It was found that bone and dentin are extrinsically toughened materials and consequently their fracture properties are best characterized utilizing a crack-growth resistance approach. A description of the different mechanical measurements commonly employed when using small animal models (rats and mice) to evaluate the influence of drug therapies on bone fragility is provided. A study where these properties were measured for a large population of wild-type rats and mice was also conducted. Given my findings, it was determined that for the most complete understanding of small animal bone it was necessary to measure strength and toughness. Strength measurements probe the flaw distribution and toughness measurements to evaluate the resistance to facture in the presence of a single dominant worst-case flaw.

  6. Dentine hypersensitivity: a review of its aetiology, pathogenesis and management.

    Science.gov (United States)

    Sykes, L M

    2007-03-01

    Dentine hypersensitivity (DH) is defined as pain arising from exposed dentine and represents a distinct clinical entity. Reported cases are increasing particularly among the younger age groups and are thought to be due to acidogenic diets, destructive habits, poor tooth brushing techniques, and the increased use of tooth whitening products. Dentine exposure may be due to a number of processes, both physical and chemical, that lead to either loss of enamel/ cementum or loss of gingival tissue. These causative factors seldom act in isolation and include erosion, abrasion, attrition, abfraction, bruxing, bleaching, medication, ageing, genetic conditions, gingival recession, and periodontal disease or procedures. There are diverse range of treatment products available, which aim at either occluding the dentinal tubules or blocking the neural transmission from the pulp. Most reversible options make use of chemical agents such as fluorides, oxalate, strontium or potassium salts, or dentine-bonding agents. Non-reversible options should only be employed after one or more of the reversible options have been attempted. These usually involve placement of permanent restorations, occlusal adjustments or periodontal flap surgery. Careful diagnosis, patient counseling and management strategies are crucial to the success of any intervention.

  7. Machining human dentin by abrasive water jet drilling.

    Science.gov (United States)

    Kohorst, Philipp; Tegtmeyer, Sven; Biskup, Christian; Bach, Friedrich-Wilhelm; Stiesch, Meike

    2014-01-01

    The aim of this experimental in-vitro study was to investigate the machining of human dentin using an abrasive water jet and to evaluate the influence of different abrasives and water pressures on the removal rate. Seventy-two human teeth had been collected after extraction and randomly divided into six homogeneous groups (n=12). The teeth were processed in the area of root dentin with an industrial water jet device. Different abrasives (saccharose, sorbitol, xylitol) and water pressures (15 or 25 MPa) were used in each group. Dimensions of dentin removal were analysed using a stripe projection microscope and both drilling depth as well as volume of abrasion were recorded. Morphological analyses of the dentin cavities were performed using scanning electron microscopy (SEM). Both drilling depth and volume of abrasion were significantly influenced by the abrasive and the water pressure. Depending on these parameters, the drilling depth averaged between 142 and 378 μm; the volume of abrasion averaged between 0.07 and 0.15 mm3. Microscopic images revealed that all cavities are spherical and with clearly defined margins. Slight differences between the abrasives were found with respect to the microroughness of the surface of the cavities. The results indicate that abrasive water jet machining is a promising technique for processing human dentin.

  8. Morfologia da dentina tratada com substâncias dessensibilizantes: avaliação através da microscopia eletrônica de varredura Morphology of dentin treated with desensitizing substances: scanning electron microscopy study

    Directory of Open Access Journals (Sweden)

    Margareth ODA

    1999-12-01

    Full Text Available As constantes recidivas dos tratamentos preconizados para a hipersensibilidade dentinária são causa de estudos a respeito desta patologia. Neste trabalho, in vitro, nos propomos a avaliar, por meio de microscopia eletrônica de varredura, a possível formação de película impermeabilizadora quando da aplicação de substâncias dessensibilizantes, acompanhada de condicionamento ácido da dentina. Discos de dentina, foram utilizados onde foi preparado um esfregaço padronizado, realizado condicionamento ácido e aplicação das substâncias testadas, à base de glutaraldeído, oxalato e fluoretos. Para compor o grupo controle um corpo-de-prova foi mantido sem tratamento e outro apenas condicionado com ácido. Dos resultados morfológicos obtidos pode-se concluir que o condicionamento ácido prévio ao tratamento com substâncias à base de glutaraldeído e de oxalato não é capaz de formar uma película uniforme, impermeabilizante sobre a dentina. O uso de fluoretos forma uma camada sobre a dentina facilmente removível, não produzindo porém efeitos a longo prazo nestes tipos de tratamento.The constant recurrence of indicated treatments for dentine hypersensitivity has motivated many studies on the subject, in the search for good long-term clinical results. The aim of this in vitro study was to evaluate, by SEM, the formation of an impermeable film when desensitizing substances are applied after acid etching of the dentine surface. Dentine discs with a standardized smear layer were acid etched with 35% phosphoric acid and substances based on glutaraldehyde, oxalate and sodium fluoride were applied according to manufacturer’s instructions. Discs without treatment were used as the control group and only one of them was acid etched. Morphological results showed that acid etching of the dentine surface prior to the application of substances based on glutaraldehyde and oxalate are not able to form a uniform, impermeable film over dentine. On

  9. ANGULAR-DEPENDENCE OF HENE-LASER LIGHT-SCATTERING BY BOVINE AND HUMAN DENTIN

    NARCIS (Netherlands)

    ZIJP, [No Value; TENBOSCH, JJ

    1991-01-01

    The scattering phase functions for HeNe-laser light of dentine sections 10-20-mu-m thick were measured. The functions perpendicular to the tubules had first-order maxima at angles of 4-degrees for bovine dentine and 5-degrees for human dentine; those parallel to the tubules showed no first-order

  10. Modification of dentin surface to enamel-like structure: A potential strategy for improving dentin bonding durability, desensitizing and self-repairing

    Directory of Open Access Journals (Sweden)

    Hongye Yang

    2014-01-01

    Full Text Available Introduction: Current theories of dentin bonding are based on the concept of "hybrid layer". However, the histological complexity of dentin, as well as the vulnerability of the hybrid layer, goes against the long-term effect of dentin bonding. At the same time, post-operative sensitivity is more likely to occur after traditional adhesive restoration. The Hypothesis: Compared to dentin bonding, enamel bonding exhibits a more optimal immediate and long-term performance, owing to its higher degree of mineralization, well-arranged enamel crystals and the porous structure after etching. Moreover, "enamel hypersensitivity" is never going to happen due to the lack of tubules existing in dentin. In light of this phenomenon, we brought up the concept and the proposal method to form an "enamel-like" dentin, simulating enamel structure to achieve satisfying durability of dentin bonding and obtain good performance for preventing post-operative sensitivity. With the application of mesoporous silicon bi-directionally binding to hydroxyapatite of dentin itself and hydroxyapatite nanorods synthetized in vitro, we may be able to form an enamel-like "functional layer" via ion-regulating self-assembly. Evaluation of Hypothesis: This paper explains how to achieve dentin enamel-like modification by chemical methods, especially, details the strategies and possible mechanisms of the hypothesis. Validation of the hypothesis is more likely to eliminate the adverse effect of dentinal fluid, improve long-term performance of dentin bonding, offer strategies for desensitizing treatment and self-repairing carious-affected dentin, and furthermore, provide the possibility to introduce new theories of dentin bonding.

  11. PENGARUH BERBAGAI KONDITIONER DENTIN (ASAM PHOSPHAT TERHADAP KEKUATAN TARIK ANTARA ADHESIVE RESIN (HNPM/TEGDMA DENGAN JARINGAN DENTIN

    Directory of Open Access Journals (Sweden)

    Andi Soufyan

    2015-07-01

    Full Text Available The aim of this research is to see the effect of various dentin conditioners (phosphoric acid to the bond strength between resin adhesive HNPM/TEGDMA (2 Hydroxy-3,2-Napthoxy-Propyl Methacrylate/Trietilen Glokol di Methacrylate and dentin tissue of bovine teeth. Dentin conditioner that was used are phosphoric acid solution 10% 25%, 35% (Group A1, A2, A3. Specimens was divided into 3 groups, each group has 10 specimens. Bond strength test used "Universal Testing Machine" AG 5000 and SHIMADZU type. The result of this research shows average differences of bond strength of each group. Anova test there is a significant difference (8.545 and p<0.05. Double comparison Tukey test among groups genereally are significant different (p<0.05 except between A2 and A3 group. The result of the research stated there are effects of various dentin conditioners to the bond strength between resin adhesive HNPM/TEGDMA and dentin tissue. 

  12. Meta-analytical review of parameters involved in dentin bonding.

    Science.gov (United States)

    De Munck, J; Mine, A; Poitevin, A; Van Ende, A; Cardoso, M Vivan; Van Landuyt, K L; Peumans, M; Van Meerbeek, B

    2012-04-01

    Bond-strength testing is the method most used for the assessment of bonding effectiveness to enamel and dentin. We aimed to disclose general trends in adhesive performance by collecting dentin bond-strength data systematically. The PubMed and EMBASE databases were used to identify 2,157 bond-strength tests in 298 papers. Most used was the micro-tensile test, which appeared to have a larger discriminative power than the traditional macro-shear test. Because of the huge variability in dentin bond-strength data and the high number of co-variables, a neural network statistical model was constructed. Variables like 'research group' and 'adhesive brand' appeared most determining. Weighted means derived from this analysis confirmed the high sensitivity of current adhesive approaches (especially of all-in-one adhesives) to long-term water-storage and substrate variability.

  13. Excimer laser interaction with dentin of the human tooth

    Science.gov (United States)

    Hammond, Ernest C., Jr.; Gilliam, Ruth L.; Baker, George R.

    1989-01-01

    The use an excimer laser produced many unusual conical structures within the dentin of the inner part of the human tooth. By varying the frequency of the laser one can disperse the energy and cause more bleeding in laser surgery, but not destroy the cells associated with the incision. Therefore, the healing process will virtually be without scarring. Whereas, using the infrared laser the blood loss would be less, but the healing process would tend to be longer because cells are being destroyed due to the cauterization effect of the laser. The question is, are these structures produced as an interaction with the laser or are they an intrinsic part of the structure. The effects of the laser interaction upon dentin was studied, and in using electron microscopy the interaction of the excimer laser upon the tooth dentin and other various biological tissue is more clearly understood.

  14. Resistance of dentin coating materials against abrasion by toothbrush.

    Science.gov (United States)

    Gando, Iori; Ariyoshi, Meu; Ikeda, Masaomi; Sadr, Alireza; Nikaido, Toru; Tagami, Junji

    2013-01-01

    Thin-film coating of root dentin surface by all-in-one adhesives has been shown to be an effective option to prevent root surface caries. The purpose of this study was to investigate the wear resistance against toothbrush abrasion of two all-in-one coating materials; Shield Force (SF) and Hybrid Coat (HC). Bovine dentin surfaces were covered with one of the coating materials; SF or HC. After storage in water for 24 h, the testing surface was subjected to the toothbrush abrasion test up to 50,000 cycles either in water or toothpaste slurry. The remaining thickness of the coating material was measured using SEM. Toothpaste slurry significantly increased rate of tooth brush abrasion of the coating materials. While SF and HC wore at a similar pace under toothbrush abrasion, SF had a thicker coat and could protect dentin longer, up to 50,000 cycles.

  15. Causa Memetika

    OpenAIRE

    Knedla, Dalibor

    2011-01-01

    This bachelor thesis focuses on the controversial topic of memetics. Memetics is rather new science which links sociology, biology and psychology together. The central aim of memetics is to explain the cultural transfer, using the Darwinian concepts of evolution. The thesis is divided into three chapters. Each chapter deals with the different perspective of the memetic theory. The first chapter describes the theory itself and foundations of the theory, the second chapter describes problematic...

  16. Factors associated with dentine hypersensitivityseverity in Colombian dental patients.

    Directory of Open Access Journals (Sweden)

    Luis López

    2016-03-01

    Full Text Available Introduction: The aim of this study was to determine the prevalence of dentine hypersensitivity (DH and examine associated etiological factors related to the severity of DH in dental clinic patients treated at the School of Dentistry at Universidad Cooperativa de Colombia, Pasto, Colombia. Materials and Methods: A cross-sectional study was designed in which three hundred and thirty three patients aged 15 to 44 years old were assessed for the presence and severity of DH. The dentine hypersensitivity diagnosis was based on self-reported sensitivity and a clinical examination. The questionnaire included socio-demographic information, data about oral health habits and acidic dietary intake. A descriptive analysis was performed and the association between DH severity and risk factors was determined using an ordinal logistic regression model. Results: Dentine hypersensitivity was detected in 88 out of 333 (26.4% subjects (95% CI: 21.83-31.56. The pH of natural juices (OR=6.013; 95% CI: 0.995-36.319, p=0.051 and pH of alcohol beverages (OR= 7.800; 95% CI: 2.282-26.658, p=0.001 were significantly associated with the severity of dentine hypersensitivity. Conclusions: The results indicated that the prevalence of dentine hypersensitivity in these patients was consistent with previous reports. Furthermore, the severity of DH was influenced by acidic diet. These results suggest that dental counseling should be provided to all patients as well as to those with dentine hypersensitivity to prevent the occurrence of this oral health problem and the severity of symptoms.

  17. Effects of different desensitizing treatments on root dentin permeability

    Directory of Open Access Journals (Sweden)

    Raydsa Raíssa Moura ROSA

    Full Text Available Abstract The objective of this study was to evaluate the effects of diode laser and a desensitizing dentifrice on dentin permeability. Fifty-two root dentin fragments were obtained (5 × 5mm and treated with 24% EDTA gel. The samples were divided into 4 groups (n = 13: G1, control (no treatment; G2, diode laser (λ = 908 nm, 1.5 W, continuous mode, 20s; G3, application of abrasive dentifrice for 1 minute (Elmex Sensitive Professional (International Gaba; and G4, application of abrasive dentifrice for 1 minute followed by irradiation with diode laser. Ten samples per group were immersed in 2% methylene blue solution for 4h. The specimens were washed, longitudinally sectioned, observed under optical microscopy, photographed and assessed based on the degree of dye leakage. The remaining samples were observed under scanning electron microscopy (SEM. The leakage data were subjected to ANOVA test, followed by Tukey’s t-test (α = 5%. Groups 2, 3 and 4 showed less dye penetration than the control group (p < 0.05, but were similar among each other. SEM images showed that dentinal tubules were open in G1, and fused and occluded in G2. Group 3 showed dentinal tubules that were occluded by the metal ions from the toothpaste. G4 presented similar characteristics to G3, and the presence of fused dentin. The diode laser and the dentifrice were effective in reducing dentinal permeability, and the combination of the two treatments did not show better results than either one used alone.

  18. Anacardic acid from brazilian cashew nut trees reduces dentine erosion.

    Science.gov (United States)

    Silveira, Cintia; Oliveira, Flávia; Dos Santos, Maria Lucilia; de Freitas, Thiago; Imparato, José Carlos; Magalhães, Ana Carolina

    2014-01-01

    The aim of this study was to analyze the effect of solutions containing saturated anacardic acid (AA) on dentine erosion in vitro. AA was chemically isolated from natural cashew nutshell liquid obtained by continuous extraction in a Soxhlet extractor and was fully saturated by catalytic hydrogenation. Matrix metalloproteinase 2 (MMP-2) activity, when exposed to buffers containing 100 µmol/l AA, was analyzed using zymography. Bovine root samples were subjected to erosive demineralization (Sprite Zero™, 4 × 90 s/day) and remineralization with artificial saliva between the erosive cycles for 5 days. The samples were treated as follows, after the first and the last acid exposure (1 min; n = 12/group): (1) 100 µmol/l epigallocatechin-3-gallate (EGCG) (positive control); (2) 0.05% NaF; (3) 100 µmol/l saturated AA; (4) saturated AA and EGCG; (5) saturated AA, EGCG and NaF; (6) untreated (negative control). Dentine erosion was measured using a contact profilometer. Two dentine samples from each group were analyzed using scanning electron microscopy. Saturated AA reduced the activity of MMP-2. ANOVA and Tukey's test revealed that all treatments significantly reduced dentine loss compared to the negative control (6.03 ± 0.98 µm). Solutions containing saturated AA (1.97 ± 1.02 µm) showed the greatest reduction in dentine erosion compared to the NaF (3.93 ± 1.54 µm) and EGCG (3.79 ± 0.83 µm) solutions. Therefore, it may be concluded that AA significantly reduces dentine erosion in vitro, possibly by acting as an MMP-2 inhibitor.

  19. Dentin dysplasia, type II: a rare autosomal dominant disorder.

    Science.gov (United States)

    Melnick, M; Eastman, J R; Goldblatt, L I; Michaud, M; Bixler, D

    1977-10-01

    Dentin dysplasia, Type II, is a rare autosomal dominant disorder. The primary teeth are amber and translucent and the pulp chambers are obliterated. The permanent teeth have a normal to brown-gray coloration and a thistle-tube pulp configuration with multiple true denticles. To date, only five families with this disorder have been reported. This article presents two additional families. Light and scanning electron microscopy of an affected primary incisor showed the dentin, including the mantle layer, to be highly disorganized throughout. Possible pathogenic events associated with the phenotype are discussed.

  20. Immunohistochemical Analysis of Matrix Metalloproteinase-13 in Human Caries Dentin

    Science.gov (United States)

    Loreto, C.; Galanti, C.; Musumeci, G.; Rusu, M.C.; Leonardi, R.

    2014-01-01

    The immunoexpression profile of matrix metalloproteinase-13 was investigated for the first time in dentin of human caries and healthy teeth. Twelve permanent premolars (10 caries and 2 sound) were decalcified in ethylenediaminetetraacetic acid and processed for embedding in paraffin wax. Sections 3-4 µm in thickness were cut and processed for immunohistochemistry. A mouse monoclonal anti-metalloproteinase-13 antibody was used for localisation using an immunoperoxidase technique. Dentinal immunoreactivity was detected in all teeth; it was weak in sound teeth and strong close to the caries area. These in vivo findings suggest a role for metalloproteinase-13 in the development and progression of adult human dental tissue disorders. PMID:24704999

  1. Making human enamel and dentin surfaces superwetting for enhanced adhesion

    Science.gov (United States)

    Vorobyev, A. Y.; Guo, Chunlei

    2011-11-01

    Good wettability of enamel and dentin surfaces is an important factor in enhancing adhesion of restorative materials in dentistry. In this study, we developed a femtosecond laser surface texturing approach that makes both the enamel and dentine surfaces superwetting. In contrast to the traditional chemical etching that yields random surface structures, this approach produces engineered surface structures. The surface structure engineered and tested here is an array of parallel microgrooves that generates a strong capillary force. Due to the powerful capillary action, water is rapidly sucked into this engineered surface structure and spreads even on a vertical surface.

  2. Influence of handpiece maintenance sprays on resin bonding to dentin

    Directory of Open Access Journals (Sweden)

    Toyotarou Sugawara

    2010-03-01

    Full Text Available Toyotarou Sugawara1, Atsushi Kameyama2, Akiko Haruyama3, Takumi Oishi4, Nobuyuki Kukidome2, Yasuaki Takase2, Masatake Tsunoda21Undergraduate Student, Tokyo Dental College, Chiba, Japan; 2Division of General Dentistry, Tokyo Dental College Chiba Hospital, Chiba, Japan; 3Department of Dental Materials Science, Tokyo Dental College, Chiba, Japan; 4Department of Dentistry and Oral Surgery, Keio University School of Medicine, Tokyo, JapanObjective: To investigate the influence of maintenance spray on resin bonding to dentin.Materials and methods: The crown of extracted, caries-free human molars was transversally sectioned with a model trimmer to prepare the dentin surfaces from mid-coronal sound dentin, and then uniformly abraded with #600 silicon carbide paper. The dentin surfaces were randomly divided into three groups: oil-free spray group where maintenance cleaner for air bearing handpieces was sprayed onto the dentin surface for 1 s and rinsed with water spray for 30 s; oil-containing spray group where maintenance cleaner for micro motor handpieces was sprayed onto the dentin surface for 1 s and rinsed with water spray for 30 s; and control group where the surface was rinsed with water spray for 30 s and then air-dried. These surfaces were then bonded with Clearfil SE Bond (Kuraray Medical, and resin composite (Clearfil AP-X, Kuraray Medical build-up crowns were incrementally constructed on the bonded surfaces. After storage for 24 h in 37°C water, the bonded teeth were sectioned into hour-glass shaped slices (0.7-mm thick perpendicular to the bonded surfaces. The specimens were then subjected to microtensile bond strength (μTBS testing at a crosshead speed of 1.0 mm/min. Data were analyzed with one-way ANOVA and the Tukey-Kramer test.Results: Maintenance spray-contaminated specimens (oil-free and oil-containing spray groups showed significantly lower μTBS than control specimens (P < 0.05. However, there was no significant difference between

  3. COHESIVE STRENGTH OF DENTIN RESISTÊNCIA COESIVA DA DENTINA

    Directory of Open Access Journals (Sweden)

    Flávio Fernando DEMARCO

    1997-07-01

    Full Text Available The bond strength of dentin adhesives to dentin has increased after each generation. Although dentin substratum is part of the bonding process, little importance has been given to measure dentin cohesive strength. The aim of this study was to evaluate the cohesive strength of dentin in human canines. Seventeen non carious canines were selected. All of them had been extracted for more than one year. The teeth were ground until dentin square samples with approximately 2 X 2 mm were obtained. They were embedded in acrylic resin and subjected to shear stress, in a Wolpert Machine, at a crosshead speed of 0.5 mm/min. The mean cohesive strength of dentin in shear mode was 33.95 (+-9.72 MPa. The fracture surfaces were observed under a X40 magnification. A finite element analysis was performed to observe the stress distribution as related to the shear test. The failure pattern was compatible with the shear test and also with the stress distribution in the finite element analysisA resistência de união dos adesivos dentinários tem sido aumentada com o desenvolvimento de cada nova geração. Pouca importância tem sido dada à resistência coesiva da dentina. A proposta deste estudo foi avaliar a resistência coesiva da dentina. Dezessete caninos humanos hígidos, os quais tinham sido extraídos há mais de um ano, foram usados. Os dentes foram desgastados até a obtenção de corpos-de-prova em dentina, de formato quadrangular, com tamanho aproximado de 2 X 2 mm. Os dentes foram incluídos em resina acrílica e, então, submetidos ao teste de cisalhamento em uma máquina de ensaios universais Wolpert, com uma velocidade de 0,5 mm/min. A resistência coesiva média da dentina no teste de cisalhamento foi de 33,95 (+- 9,72 MPa. O tipo de fratura foi analisado com um aumento de 40X. Foi realizada uma análise com elemento finito, para observar a distribuição do estresse relacionada com o teste de cisalhamento. O padrão de fratura encontrado foi compat

  4. Causas genéticas de deficiência de ferro

    OpenAIRE

    Saad, Sara Teresinha O.

    2010-01-01

    As causas genéticas de deficiência de ferro, real ou funcional, ocorrem por defeitos em muitas proteínas envolvidas na absorção e metabolismo de ferro. Neste capítulo descreveremos sucintamente causas genéticas de carência de ferro para a síntese de hemoglobina, que cursa então com anemia microcítica e hipocrômica. Ressalto que estas são alterações raras, com poucas descrições na literatura. Em alguns casos, o ferro funcional não está disponível para os eritroblastos sintetizarem hemoglobina,...

  5. Tromboembolia coronaria múltiple como causa de infarto agudo de miocardio

    Directory of Open Access Journals (Sweden)

    Brenda N. Mangariello

    2010-01-01

    Full Text Available RESUMENLa tromboembolia coronaria es una causa infrecuente y poco documentada de síndromecoronario agudo. En la bibliografía sólo se encuentran comunicaciones aisladas con escasafundamentación angiográfica. En esta presentación se describe el caso de un varón de 32años sin antecedentes cardiovasculares, que debuta con un cuadro de infarto agudo demiocardio con evidencia angiográfica de múltiples tromboembolias coronarias y evolucionaa shock cardiogénico y muerte. Se realiza, asimismo, una revisión de las causas y de lasformas de presentación clínica de la tromboembolia coronaria.REV ARGENT CARDIOL 2010;78:255-258.

  6. Effects of decalcification on bulk and compound-specific nitrogen and carbon isotope analyses of dentin.

    Science.gov (United States)

    Brault, Emily K; Koch, Paul L; Gier, Elizabeth; Ruiz-Cooley, R I; Zupcic, Jessica; Gilbert, Kwasi N; McCarthy, Matthew D

    2014-12-30

    For bulk carbon and nitrogen isotope analysis of dentin, samples are typically decalcified. Since the non-protein carbon in dentin is low, whole sample analysis may produce reliable data. Compound-specific isotope analysis (CSIA) of bone and tooth dentin protein is a powerful tool for reconstructing the flow of carbon and nitrogen in modern and past food webs. Decalcification has also been used to prepare bone and dentin samples for CSIA, but the effects of this process on bulk dentin, amino acid composition, and their specific isotope values are not known. The bulk isotope values of raw and decalcified dentin from a sperm whale tooth were measured to determine the effects of decalcification and the accuracy of untreated dentin results. CSIA was also performed on decalcified and raw dentin to examine differences in the amino acid isotope values and molar composition between these two approaches. Analysis of raw dentin yields precise and accurate bulk isotope measurements for this animal. The isotopic values of decalcified samples and raw dentin for individual amino acids were similar, but the average of the isotope value offsets between the two sample types was significant. The presence of inorganic material complicated raw sample processing for individual amino acid isotope values, and may have contributed to the isotopic differences between decalcified and raw samples. Decalcification is not needed to measure bulk isotope values in dentin from this modern odontocete, probably because the lipid and carbonate concentrations are low and the carbon isotope values of dentin protein and carbonate are similar. This method should not be applied in some cases (e.g., with fossil dentin and modern bone). Decalcification should still be used prior to CSIA since significant matrix issues occur with raw dentin processing and decalcification does not alter the amino acid molar composition or isotopic values of dentin. Copyright © 2014 John Wiley & Sons, Ltd.

  7. Óbito fetal em microrregião de Minas Gerais: causas e fatores associados

    Directory of Open Access Journals (Sweden)

    Nurdan Nestor

    2003-01-01

    Full Text Available OBJETIVOS: estudar as causas e fatores associados ao óbito fetal. MÉTODOS: estudo epidemiológico descritivo, que incluiu 190 casos de perdas fetais entre 11.825 gestantes que parturiram nos dois únicos hospitais (Casa de Saúde Divino Espírito Santo e Hospital Nossa Senhora Auxiliadora de Caratinga, MG, no período de 1º de janeiro de 1995 a 30 de abril de 2000. As variáveis investigadas foram: o número de gestações, a idade gestacional no momento da internação hospitalar, a época de ocorrência do decesso fetal em relação ao parto e a causa do óbito fetal. Não havendo grupo controle comparativo, utilizou-se estatística descritiva com tabelas, porcentagens e médias aritméticas. RESULTADOS: dentre as 189 gestantes com morte fetal, 77 eram primigestas e 76 tinham entre 2 e 5 gestações. A idade gestacional variou de 20 a 37 semanas. Em relação ao parto, a perda fetal ocorreu no período anteparto em 164 dos 190 casos. As causas mais freqüentes encontradas para a morte foram: DPP em 35, anomalia fetal em 12 e síndrome hipertensiva em 8 casos. Todavia, em 117 conceptos não foi possível esclarecer a etiologia do óbito. CONCLUSÕES: a morte fetal esteve presente notadamente nas primigestas (40,74% internadas no pré-termo (59,79%, e ocorreram no período anteparto (86,31%. Dentre as causas de morte fetal, a mais encontradiça foi o DPP (18,42% e em 61,57% dos casos ela não pôde ser determinada.

  8. Desarrollo centrado en el usuario de un juego "causa-efecto" sobre Android

    OpenAIRE

    Blanco Alonso, Alvaro

    2014-01-01

    El objetivo de este proyecto consiste en realizar una juego del tipo ”causa-efecto” para el centro Obregón de Valladolid. Este centro se dedica a ayudar a personas con discapacidad intelectual severa. La metodología de trabajo consistirá en desarrollar un diseño centrado en el usuario. Grado en Ingeniería Informática

  9. Investidura com a doctor honoris causa de l'Excm. Sr. Ángel Carlos Pellicer

    OpenAIRE

    Diversos autors

    1997-01-01

    Investidura com a doctor honoris causa del senyor Ángel Carlos Pellicer. Sessió acadèmica extraordinària, 16 de maig de 1997. Elogi del candidat a càrrec del doctor Albert Bordons. Discurs d’investidura pronunciat pel senyor Ángel Carlos Pellicer. Paraules de benvinguda pronunciades pel doctor Joan Martí i Castell Rector Magfc. de la Universitat.

  10. Principales causas de la morosidad en la jurisdicción laboral

    OpenAIRE

    Rafael Ospina Morales

    2006-01-01

    El proyecto desarrollado es de gran magnitud e importancia, toda vez que surgen cascadas de leyes que al poco tiempo de su vigencia, están siendo modificadas, adicionadas o derogadas, por quienes solucionan todos los problemas de Estado con sus administrados, expidiendo leyes, SINAVERIGUARLAS CAUSAS que han generado la patología social en determinado momento. La Ley debe tener en cuenta el fenómeno social, pero no a la ligera, sino profundizando sobre el origen y ...

  11. Optical properties of human radicular dentin: ATR-FTIR characterization and dentine tubule direction influence on radicular post adhesion

    Science.gov (United States)

    Quinto, Jose; Zamataro, Claudia B.; Benetti, Carolina; Dias, Derly A.; Blay, Alberto; Zezell, Denise Maria

    2015-06-01

    Knowledge of dental structures is essential for understanding of laser interaction and its consequences during adhesion processes. Tubule density in dentin ranges from 4.900 to 90.000 per mm2, for diameters from 1 to 3 μm. Light propagation inside the tubules is associated with tubules orientation. To the best of our knowledge, there is no previous work in literature characterizing physical-chemical alterations in dentin. The dentin samples were irradiated with a Er,Cr:YSGG Laser at wavelength 2.78 μm, with an energy density of 9.46 J/cm2 , above the ablation threshold. ATRFTIR at wavenumbers 2000 to 700 cm-1 was used to evaluate the differences among third root region and tubules orientation.

  12. Effect of immediate and delayed dentin sealing on the fracture strength, failure type and Weilbull characteristics of lithiumdisilicate laminate veneers

    NARCIS (Netherlands)

    Gresnigt, Marco M.M.; Cune, Marco S.; de Roos, Joanne G.; Özcan, Mutlu

    OBJECTIVES: Adhesion on dentin is less reliable than on enamel, which could affect the durability of laminate veneers (LV). Immediate dentin sealing (IDS) is suggested instead of delayed dentin sealing (DDS) to overcome hypersensitivity and prevent debonding from dentin. This study evaluated the

  13. LA EVO-DEVO COMO CIENCIA HISTÓRICA DE CAUSAS REMOTAS

    Directory of Open Access Journals (Sweden)

    GUSTAVO CAPONI

    2009-01-01

    Full Text Available Partiendo de la premisa de que una causa próxima es aquella cuyos efectos pueden ser registrados en los estados de un organismo individual. En este trabajo sostendré que lo que define a una causa remota es el hecho de que sus efectos puedan ser registrados en la evolución de linajes, y no simplemente en estados poblacionales. Esto, por otra parte, no solo nos permitirá entender en qué sentido los constreñimientos ontogenéticos deben ser comprendidos como causas remotas de los fenómenos evolutivos; sino que además nos permitirá poner en evidencia el carácter eminentemente histórico de la Biología evolucionaria del desarrollo que Wallace Arthur subestimó en Biased Embryos and Evolution. Así, y siguiendo esta última línea de razonamiento, también intentaré mostrar que, aunque la acción de dichos constreñimientos ontogenéticos pueda verificarse más allá de los límites de una población o especie particular, eso no implica que estemos asistiendo a un retorno del pensamiento tipológico en Biología evolucionaria.

  14. Effect of Repeated Container Lid Opening on Dentin Shear Bond Strength of Two Dentin Adhesive Systems

    Directory of Open Access Journals (Sweden)

    H. Hassanzadeh

    2008-03-01

    Full Text Available Objective: Comparing the effect of repeated opening of the container lid of two dentin adhesive systems, Prime&Bond NT (P&B NT and iBond (iB, on shear bond strength.Materials and Methods: Intact bovine lower incisors (n=60, fixed in acrylic were ran-domly divided into six groups (n=10. Groups I and II were set as control groups. P&B NT and iB were applied on the samples after five days a week, three times a day for two weeks of use in groups III and VI; and after four weeks of use in groups V and VI. The samples were evaluated by a universal testing-machine (Instron, cross-head speed 1mm/min and stereomicroscope.Results: There was no significant difference between the bond strengths in any of the three P&B NT. The mean amount of the shear bond strength for iB after 60 times of use (15.31 MPa was significantly lowerthan that at the baseline (23.51 MPa. There was no significant difference between iB at the baseline and after 30 times of use (19.26 Mpa, and also between iB after 30 times of use and after 60 times of use. All P&B NT groups showed significantly highershear bond strengths when compared with their similar iB groups in iB.Conclusion: Repeated use (60 times of the all-in-one adhesive container seems to reduce dentin shear bond strength. Therefore, containers with a lower content of the same adhe-sive or a single-dose of the adhesive are preferred.

  15. Microtensile dentin bond strength of fifth with five seventh-generation dentin bonding agents after thermocycling: An in vitro study

    OpenAIRE

    Poptani, Bruhvi; Gohil, K. S.; Ganjiwale, Jaishree; Shukla, Manisha

    2012-01-01

    Objectives: The objective of this in vitro study was to compare the microtensile dentin bond strength (μTBS) of five seventh-generation dentin bonding agents (DBA) with fifth-generation DBA before and after thermocycling. Materials and Methods: Ten extracted teeth were assigned to fifth generation control group (optibond solo) and each of the five experimental groups namely, Group I (G-Bond) ,Group II (S 3 Clearfil), Group III (One Coat 7.0), Group IV (Xeno V), and Group V (Optibond all in on...

  16. Causas básicas e associadas de morte por Aids, Estado de São Paulo, Brasil, 1998

    Directory of Open Access Journals (Sweden)

    Santo Augusto Hasiak

    2000-01-01

    Full Text Available OBJETIVOS: Descrever o padrão da mortalidade devida a Aids segundo causas básica e associadas de morte no Estado de São Paulo, em 1998. MÉTODOS: Os dados sobre a mortalidade e a população residente no Estado de São Paulo, SP, para 1998, foram obtidos na Fundação Sistema Estadual de Análise de Dados (Seade. As causas de morte foram codificadas pelas disposições da Décima Revisão da Classificação Estatística Internacional de Doenças e Problemas Relacionados à Saúde. Os registros de Aids como causa básica e associada de morte foram recuperados e revistos. RESULTADOS: A Aids foi a causa básica em 4.619 mortes, correspondendo à décima causa (2,0% e ao coeficiente de mortalidade de 13,1 por 100.000 habitantes. As razões das mortes e os respectivos coeficientes entre homens e mulheres foram de 2,4 e 2,5. A Aids foi a segunda causa entre os homens de 20 a 34 anos de idade e entre as mulheres de 25 a 34. A idade média ao morrer entre as mulheres (34,1±12,2 anos foi estatisticamente menor que a dos homens (36,4±10,7 anos -- p<0,001. As principais causas associadas em mortes por Aids foram a insuficiência respiratória (36,1%, pneumonias (27,0%, tuberculose (19,6%, septicemias (18,6%, toxoplasmose (12,2%, pneumonia por P. carinii (8,3% e caquexia (7,9%. A Aids apresentou-se como causa associada em outras 84 mortes. As principais causas básicas destas mortes foram neoplasias malignas (28/84, afecções devidas ao uso do álcool (23/84 e diabetes mellitus (7/84. A idade média ao morrer por Aids como causa básica (35,7±11,2 anos foi estatisticamente menor que a idade média nas mortes em que Aids foi mencionada como causa associada (39,9±11,8 anos -- p<0,001. CONCLUSÕES: As causas múltiplas de morte resgatam parcialmente a história natural da Aids e oferecem subsídios para medidas preventivas adequadas e específicas.

  17. Causas de aborto bovino diagnosticadas no Setor de Patologia Veterinária da UFRGS de 2003 a 2011

    OpenAIRE

    Nadia A.B. Antoniassi; Gregory D. Juffo; Adriana S. Santos; Caroline A. Pescador; Luis G. Corbellini; David Driemeier

    2013-01-01

    Descrevem-se as causas de aborto bovino diagnosticadas no Setor de Patologia Veterinária da Universidade Federal do Rio Grande do Sul no período de janeiro de 2003 a dezembro de 2011. Um total de 490 fetos bovinos foi analisado neste período. Causas específicas de aborto foram encontradas em 46,7% dos casos. Infecções por protozoários, em especial Neospora caninum acometeram 33% dos casos (162/490). Bactérias com 6,3% (31/490), seguidas por fungos com 0,8% (4/490) dos casos, foram causas adic...

  18. Sobrepeso y obesidad como causas de óbito fetal: revisión sistemática de literatura

    OpenAIRE

    Pinzon Gómez, Maria del Pilar; Rios Galindo, Alejandra Paola

    2015-01-01

    La obesidad es una de las causas de óbito fetal documentadas en la literatura, pero actualmente no hay datos conclusivos sobre el efecto del sobrepeso como causa de óbito. Con la presente revisión sistemática se pretendió evaluar la evidencia relacionada con las alteraciones de peso como causa de óbito fetal. Se realizó una revisión sistemática de la literatura en múltiples bases de datos incluyendo la mejor evidencia relacionada con el tema en un periodo de cinco años. El sobrepeso/obesi...

  19. Structure and microstructure of coronary dentin in non-erupted human deciduous incisor teeth

    Directory of Open Access Journals (Sweden)

    Costa Luciane R.R S.

    2002-01-01

    Full Text Available The dentin structure of non-erupted human deciduous mandibular and maxillary central and lateral incisor teeth was studied employing light and scanning electron microscopy. For light microscopy, nitric-acid-demineralized and ground sections were used. The sections were stained by hematoxylin-eosin, picrosirius and azo-carmim methods, and ground specimens were prepared using a carborundum disk mounted in a handpiece. For SEM study, teeth were frozen in liquid nitrogen and fractured at longitudinal and transversal directions. Structurally, demineralization and ground methods revealed tubules with primary and secondary curvatures, canaliculi, giant tubules, interglobular dentin, predentin, and intertubular dentin. Scanning electron microscopy showed three-dimensional aspects of dentinal tubules, canaliculi, peritubular dentin, intertubular dentin, and predentin. This study contributes to knowledge about dentin morphology showing characteristics of teeth not yet submitted to mastication stress.

  20. Clinical effects of glass ionomer restorations on residual carious dentin in primary molars.

    Science.gov (United States)

    Smales, Roger J; Ngo, Hien C; Yip, Kevin H K; Yu, Chang

    2005-06-01

    To evaluate the mineralization and morphology of residual (infected and affected) carious dentin following the restoration of vital primary molars with viscous glass-ionomer cement (GIC). Encapsulated Fuji IX GP and Ketac-Molar Aplicap GICs were placed in cavities that were prepared using the atraumatic restorative treatment (ART) approach. Four suitable exfoliated teeth with intact restorations were sectioned and then examined by electron probe microanalysis (EPMA) and scanning electron microscopy (SEM). EPMA demonstrated the presence of fluorine and strontium that had penetrated into the underlying residual carious dentin from the adjacent GIC. The concentrations of these two elements, and those of calcium and phosphorous, varied with distance from the GIC/dentin interface. SEM showed varying degrees of dentin tubule destruction and intratubular (peritubular) dentin present immediately subjacent to the GIC/dentin interface. Incomplete removal of carious dentin was observed in all specimens, and GIC remained adherent to the tissue.

  1. Associations, causation and model in psychiatry Associações, causas e modelos em psiquiatria

    Directory of Open Access Journals (Sweden)

    Dorgival Caetano

    2009-01-01

    êm implicações para a prática clínica. Causa e efeito constituem um fenômeno complexo, podendo a mesma causa ter diferentes efeitos e, inversamente, o mesmo efeito, uma gama diferente de causas. Nos transtornos mentais e no comportamento humano há sempre uma cadeia de eventos iniciada por uma causa indireta e remota; seguida por causas intermediárias; e por último, uma causa direta e imediata. As causas dos transtornos mentais podem ser agrupadas em: (i necessárias e suficientes; (ii necessárias, mas não suficientes; e (iii nem necessárias nem suficientes, mas se presentes, aumentam o risco para a ocorrência de transtornos mentais.

  2. Compounded PHOSPHO1/ALPL deficiencies reduce dentin mineralization.

    Science.gov (United States)

    McKee, M D; Yadav, M C; Foster, B L; Somerman, M J; Farquharson, C; Millán, J L

    2013-08-01

    Phosphatases are involved in bone and tooth mineralization, but their mechanisms of action are not completely understood. Tissue-nonspecific alkaline phosphatase (TNAP, ALPL) regulates inhibitory extracellular pyrophosphate through its pyrophosphatase activity to control mineral propagation in the matrix; mice without TNAP lack acellular cementum, and have mineralization defects in dentin, enamel, and bone. PHOSPHO1 is a phosphatase found within membrane-bounded matrix vesicles in mineralized tissues, and double ablation of Alpl and Phospho1 in mice leads to a complete absence of skeletal mineralization. Here, we describe mineralization abnormalities in the teeth of Phospho1(-/-) mice, and in compound knockout mice lacking Phospho1 and one allele of Alpl (Phospho1(-/-);Alpl(+/-) ). In wild-type mice, PHOSPHO1 and TNAP co-localized to odontoblasts at early stages of dentinogenesis, coincident with the early mineralization of mantle dentin. In Phospho1 knockout mice, radiography, micro-computed tomography, histology, and transmission electron microscopy all demonstrated mineralization abnormalities of incisor dentin, with the most remarkable findings being reduced overall mineralization coincident with decreased matrix vesicle mineralization in the Phospho1(-/-) mice, and the almost complete absence of matrix vesicles in the Phospho1(-/-);Alpl(+/-) mice, whose incisors showed a further reduction in mineralization. Results from this study support prominent non-redundant roles for both PHOSPHO1 and TNAP in dentin mineralization.

  3. Compounded PHOSPHO1/ALPL Deficiencies Reduce Dentin Mineralization

    Science.gov (United States)

    McKee, M.D.; Yadav, M.C.; Foster, B.L.; Somerman, M.J.; Farquharson, C.; Millán, J.L.

    2013-01-01

    Phosphatases are involved in bone and tooth mineralization, but their mechanisms of action are not completely understood. Tissue-nonspecific alkaline phosphatase (TNAP, ALPL) regulates inhibitory extracellular pyrophosphate through its pyrophosphatase activity to control mineral propagation in the matrix; mice without TNAP lack acellular cementum, and have mineralization defects in dentin, enamel, and bone. PHOSPHO1 is a phosphatase found within membrane-bounded matrix vesicles in mineralized tissues, and double ablation of Alpl and Phospho1 in mice leads to a complete absence of skeletal mineralization. Here, we describe mineralization abnormalities in the teeth of Phospho1-/- mice, and in compound knockout mice lacking Phospho1 and one allele of Alpl (Phospho1-/-;Alpl+/-). In wild-type mice, PHOSPHO1 and TNAP co-localized to odontoblasts at early stages of dentinogenesis, coincident with the early mineralization of mantle dentin. In Phospho1 knockout mice, radiography, micro-computed tomography, histology, and transmission electron microscopy all demonstrated mineralization abnormalities of incisor dentin, with the most remarkable findings being reduced overall mineralization coincident with decreased matrix vesicle mineralization in the Phospho1-/- mice, and the almost complete absence of matrix vesicles in the Phospho1-/-;Alpl+/- mice, whose incisors showed a further reduction in mineralization. Results from this study support prominent non-redundant roles for both PHOSPHO1 and TNAP in dentin mineralization. PMID:23694930

  4. Apoptosis Activation in Human Carious Dentin. An Immunohistochemical Study

    Science.gov (United States)

    Loreto, C.; Psaila, A.; Musumeci, G.; Castorina, S.; Leonardi, R.

    2015-01-01

    The exact mechanisms and enzymes involved in caries progression are largely unclear. Apoptosis plays a key role in dentin remodelling related to damage repair; however, it is unclear whether apoptosis in decayed teeth is activated through the extrinsic or the intrinsic pathway. This ex vivo immunohistochemical study explored the localization of TRAIL, DR5, Bcl-2 and Bax, the main proteins involved in apoptosis, in teeth with advanced caries. To evaluate TRAIL, DR5, Bcl-2 and Bax immunoexpressions twelve permanent carious premolars were embedded in paraffin and processed for immunohistochemistry. The results showed that TRAIL and DR5 were overexpressed in dentin and in pulp vessels and mononuclear cells; strong Bax immunostaining was detected in dilated dentinal tubules close to the lesion, and Bcl-2 staining was weak in some dentin areas under the cavity or altogether absent. These findings suggest that both apoptosis pathways are activated in dental caries. Further studies are required to gain insights into its biomolecular mechanisms. PMID:26428882

  5. In vitro reparative dentin: a biochemical and morphological study

    Directory of Open Access Journals (Sweden)

    G. Teti

    2013-08-01

    Full Text Available In this study, starting from human dental pulp cells cultured in vitro, we simulated reparative dentinogenesis using a medium supplemented with different odontogenic inductors. The differentiation of dental pulp cells in odontoblast-like cells was evaluated by means of staining, and ultramorphological, biochemical and biomolecular methods. Alizarin red staining showed mineral deposition while transmission electron microscopy revealed a  synthesis of extracellular matrix fibers during the differentiation process. Biochemical assays demonstrated that the differentiated phenotype expressed odontoblast markers, such as Dentin Matrix Protein 1 (DMP1 and Dentin Sialoprotein (DSP, as well as type I collagen. Quantitative data regarding the mRNA expression of DMP1, DSP and type I  collagen were obtained by Real Time PCR. Immunofluorescence data demonstrated the various localizations of DSP and DMP1 during odontoblast differentiation. Based on our results, we obtained odontoblast-like cells which simulated the reparative dentin processes in order to better investigate the mechanism of odontoblast differentiation, and dentin extracellular matrix deposition and mineralization. 

  6. Bonding longevity of flowable GIC layer in artificially carious dentin

    NARCIS (Netherlands)

    Tedesco, T.K.; Bonifácio, C.C.; Hesse, D.; Kleverlaan, C.J.; Lenzi, T.L.; Raggio, D.P.

    2014-01-01

    Purpose To evaluate the bond longevity of glass ionomer cement (GIC) to sound and artificially carious dentin, using a high viscosity material with regular consistency and using a flowable GIC, after one year water storage. Material and methods Sixty bovine incisors were polished to obtain flat

  7. Bio-reconstruction of root canal using dentin post

    Directory of Open Access Journals (Sweden)

    Navin Mishra

    2013-01-01

    Full Text Available This case report describes the successful management of complicated crown fracture of left maxillary central incisor (#21 of 23-year-old male using dentin (biological post made from human tooth. Endodontic treatment was initiated and sectional obturation was done using ProTaper gutta-percha and AH Plus sealer. The coronal space was modified to receive a human dentin post. A two-step procedure comprising direct and indirect technique of post fabrication was done to achieve the accuracy of biological post. A maxillary cuspid from an institutional tooth bank was taken, sectioned mesiodistally using a diamond disc simulating the length and thickness of mock post. Dentin post was first verified on the plaster model and then cemented in tooth #21. Core build up was done with composite and porcelain fused to metal (PFM crown was luted. On the follow-up visits, patient was asymptomatic and radiographic evaluation revealed normal periradicular architecture. Biological posts may be good alternatives to conventional post systems as they preserve internal dentin walls, provide excellent adhesion, and resilience similar to natural tooth structure.

  8. Microtensile bond strength between adhesive cements and root canal dentin

    OpenAIRE

    Bouillaguet, Serge; Troesch, Sabra; Wataha, John C.; Krejci, Ivo; Meyer, Jean Marc; Pashley, David H

    2003-01-01

    The hypotheses tested were that the bond strength of adhesive cements to root canal dentin (1) would be reduced as a function of configuration factor, polymerization process and type of luting material and (2) would be lowered near the apex of the tooth.

  9. Wnt signaling regulates pulp volume and dentin thickness.

    Science.gov (United States)

    Lim, Won Hee; Liu, Bo; Cheng, Du; Hunter, Daniel J; Zhong, Zhendong; Ramos, Daniel M; Williams, Bart O; Sharpe, Paul T; Bardet, Claire; Mah, Su-Jung; Helms, Jill A

    2014-04-01

    Odontoblasts, cementoblasts, ameloblasts, and osteoblasts all form mineralized tissues in the craniofacial complex, and all these cell types exhibit active Wnt signaling during postnatal life. We set out to understand the functions of this Wnt signaling, by evaluating the phenotypes of mice in which the essential Wnt chaperone protein, Wntless was eliminated. The deletion of Wls was restricted to cells expressing Osteocalcin (OCN), which in addition to osteoblasts includes odontoblasts, cementoblasts, and ameloblasts. Dentin, cementum, enamel, and bone all formed in OCN-Cre;Wls(fl/fl) mice but their homeostasis was dramatically affected. The most notable feature was a significant increase in dentin volume and density. We attribute this gain in dentin volume to a Wnt-mediated misregulation of Runx2. Normally, Wnt signaling stimulates Runx2, which in turn inhibits dentin sialoprotein (DSP); this inhibition must be relieved for odontoblasts to differentiate. In OCN-Cre;Wls(fl/fl) mice, Wnt pathway activation is reduced and Runx2 levels decline. The Runx2-mediated repression of DSP is relieved and odontoblast differentiation is accordingly enhanced. This study demonstrates the importance of Wnt signaling in the homeostasis of mineralized tissues of the craniofacial complex. © 2014 American Society for Bone and Mineral Research.

  10. Mechanical or cold lateral compaction: The incidence of dentinal defects

    Directory of Open Access Journals (Sweden)

    Seyed Mohsen Hasheminia

    2015-01-01

    Full Text Available Background: The incidence of dentinal defects may influence the outcome of root canal treatment. The aims of this study were to evaluate and compare the incidence of dentinal defects following root canal obturation with two different techniques. Materials and Methods: A total of 110 mesial roots of human mandibular first molars were selected. Twenty-seven roots were left unprepared as negative controls (NCs. The mesiobuccal canals of 83 roots were prepared using rotary instruments. Twenty-seven roots were left unobturated as positive controls (PCs. Twenty-eight roots were obturated with cold lateral compaction (CLC technique and the others were obturated with mechanical lateral compaction (MLC technique. In the CLC and MLC groups, spreader penetration depth was measured by an electromechanical testing machine in canals containing master Gutta-percha cones. After root canal obturation, all the roots were sectioned horizontally at four levels from the apex and evaluated under a stereomicroscope at a magnification of ×40. The presence of dentinal defects was noted. Data were analyzed using the Chi-square and t-tests. Results: The number of defects was not significantly different between the CLC, MLC, and PC groups. The CLC, MLC, and PC groups had significantly more defects compared to the NC group. Conclusion: According to the results of this study, the MLC and CLC techniques were the same in producing dentinal defects.

  11. Penetration of varnishes into demineralized root dentine in vitro

    NARCIS (Netherlands)

    Arends, J; Duschner, H; Ruben, JL

    1997-01-01

    In this paper the penetration of three different varnishes employed in caries prevention (Duraphat(R), Fluor Protector(R) and Cervitec(R)) into demineralized dentine is quantified using confocal laser scanning microscopy. The results show that the varnish penetration into lesions about 85 mu m in

  12. APF and dentifrice effect on root dentin demineralization and biofilm

    NARCIS (Netherlands)

    Vale, G.C.; Tabchoury, C.P.M.; Del Bel Cury, A.A.; Tenuta, L.M.A.; ten Cate, J.M.; Cury, J.A.

    2011-01-01

    Because dentin is more caries-susceptible than enamel, its demineralization may be more influenced by additional fluoride (F). We hypothesized that a combination of professional F, applied as acidulated phosphate F (APF), and use of 1100-ppm-F dentifrice would provide additional protection for

  13. Amalgam stained dentin: a proper substrate for bonding resin composite?

    NARCIS (Netherlands)

    Scholtanus, J.D.

    2016-01-01

    Nowadays the use of dental amalgam is mostly abandoned and substituted by tooth colored resin composites that can be bonded to teeth tissues by adhesive techniques. The aim of this thesis was to find out whether dark stained dentin, as often observed after removal of amalgam restorations and

  14. Midinfrared ablation of dentin with the Vanderbilt FEL

    Science.gov (United States)

    Harris, David M.; Reinisch, Lou; Edwards, Glenn S.; Yessik, Michael J.; Ashrafi, Shahid; Santos-Sacchi, Joseph

    1996-04-01

    Absorption spectra of 0.1 - 0.2 mm thick, dehydrated sections of human teeth were measured in the transmission mode with a Bruker FT-IR spectrometer from 2.5 - 20 micrometers . Absorption peaks for amide I, II and III, carbonate and phosphate were identified. Craters were ablated in dentin and enamel using a tunable FEL at 6.45 micrometers at various fluences. Pulse duration: 3 microsecond(s) ; spot size (Gaussian, FWHM): 300 micrometers ; repetition rate: 10 Hz. Crater depth and width were measured from digitized optical images. Ablation rates were computed from crater depth and volume data. Selected specimens were examined with scanning electron microscopy to determine ablation surface characteristics. Depth of thermal damage and dentinal tubule morphology were estimated from SEM examination of fractures through ablation sites. Functions describing crater depth vs. number of pulses (quadratic function) were not the same as crater volume vs. number of pulses (linear function). Crater depth decreases with successive pulses, concurrently, the crater width increases. Thus, each pulse removes approximately a constant volume. Material was observed to flow through the dentinal tubules during and after ablation. Patent tubules on crater walls and floor were observed with SEM. Ablation rates in dentin were approximately 3X those in enamel at 6.45 micrometers . Ablation rates and surface characteristics varied across wavelengths from 5.8 to 8.0 micrometers .

  15. Dentinal sensitivity, self-reported gingivo-dental conditions ...

    African Journals Online (AJOL)

    Dental appearance satisfaction was expressed by 77.0% of the participants while 8.2% use or believe that they will use artificial teeth with ageing. Dentinal sensitivity was significantly associated with texture of toothbrush, receipt of professional instruction on tooth brushing, dental appearance satisfaction and food packing.

  16. Effect of different EGTA concentrations on dentin microhardness

    Directory of Open Access Journals (Sweden)

    Cruz-Filho Antonio Miranda da

    2002-01-01

    Full Text Available The effect of 1%, 3% and 5% EGTA (ethylene glycol-bis-(b-amino-ethyl ether N,N,N,N-tetra-acetic acid on the microhardness of root dentin of the cervical third of human teeth was studied. Five newly extracted maxillary incisors were sectioned transversely at the cementoenamel junction, and the crowns were discarded. The roots were embedded in blocks of high-speed polymerized acrylic resin and cut transversely into 1-mm sections. The second section of the cervical third of the root of each tooth was sectioned and divided into four parts. Each part was placed on an acrylic disc that was used as a base for microhardness measurement. Fifty microliters of 1% EGTA, 3% EGTA, or 5% EGTA were applied to the dentin surface. Deionized and distilled water was used as control. Dentin microhardness was then measured with a load of 50 g for 15 s. Statistical analysis showed that the three concentrations of the chelating solution EGTA significantly reduced dentin microhardness when compared with water (ANOVA, p<0.01, and that there was a statistically significant difference among the three solutions (Tukey test, p<0.05.

  17. Influence of dentin pretreatment on bond strength of universal adhesives.

    Science.gov (United States)

    Poggio, Claudio; Beltrami, Riccardo; Colombo, Marco; Chiesa, Marco; Scribante, Andrea

    2017-01-01

    Objective: The purpose of the present study was to compare bond strength of different universal adhesives under three different testing conditions: when no pretreatment was applied, after 37% phosphoric acid etching and after glycine application. Materials and methods: One hundred and fifty bovine permanent mandibular incisors were used as a substitute for human teeth. Five different universal adhesives were tested: Futurabond M+, Scotchbond Universal, Clearfil Universal Bond, G-Premio BOND, Peak Universal Bond. The adhesive systems were applied following each manufacturer's instructions. The teeth were randomly assigned to three different dentin surface pretreatments: no pretreatment agent (control), 37% phosphoric acid etching, glycine pretreatment. The specimens were placed in a universal testing machine in order to measure and compare bond strength values. Results: The Kruskal-Wallis analysis of variance and the Mann-Whitney test were applied to assess significant differences among the groups. Dentin pretreatments provided different bond strength values for the adhesives tested, while similar values were registered in groups without dentin pretreatment. Conclusions: In the present report, dentin surface pretreatment did not provide significant differences in shear bond strength values of almost all groups. Acid pretreatment lowered bond strength values of Futurabond and Peak Universal Adhesives, whereas glycine pretreatment increased bond strength values of G Praemio Bond adhesive system.

  18. Interactions between root canal irrigants, sealers and dentin

    NARCIS (Netherlands)

    Neelakantan, P.

    2016-01-01

    The objective of this thesis was to determine the interactions between root filling materials and root dentin and to investigate if root canal irrigating solutions had an impact on these interactions. The following outcomes were assessed in the studies encompassed in this thesis: (i) dislocation

  19. Variação espacial das principais causas dos incêndios florestais em Portugal (2001-2012)

    OpenAIRE

    Nunes, A.; Lourenço, L.; Meira Castro, A C; Fernandes, S.

    2014-01-01

    O conhecimento das causas dos incêndios florestais, e dos respetivos fatores de ignição, é indispensável para a eficaz implementação de medidas que visem a prevenção da sua ocorrência. Na bacia do Mediterrâneo as causas que estão na origem dos incêndios florestais são maioritariamente humanas, ficando a dever-se a causas naturais uma ínfima parte das ignições. Por sua vez, as causas dos incêndios, além de diferirem de país para país, são também espacialmente distintas dentro do mesmo país, po...

  20. Assessment of dysplastic dentin in osteogenesis imperfecta and dentinogenesis imperfecta.

    Science.gov (United States)

    Malmgren, Barbro; Lindskog, Sven

    2003-04-01

    Two semiquantitative scoring systems, Clinical Radiographic Score (CRS) and Dysplastic Dentin Score (DDS), were introduced for analyzing degree of dysplastic manifestations in dentin. The utility of both systems was demonstrated in a large material of teeth from patients with dentinogenesis imperfecta (DI) and osteogenesis imperfecta (OI). Twenty teeth from healthy controls, 81 teeth from 40 patients with OI, and 18 teeth with DI without OI (DI type II) were examined. The degree of dysplasia was correlated with type and form of OI and type of DI. The median DDS did not differ between DI associated with OI (DI type I) and DI type II. DDS in OI patients without clinical signs of DI was above that of control teeth. Both circumpulpal and mantle dentin showed increased DDS, although circumpulpal dentin was more severely affected. The median DDS was highest for the most severe type of non-lethal OI (type III). DDS increased significantly with form (severity) of OI. A significant association between DDS and CRS was found, although diagnosis of DI in less severe cases was not possible based on radiographic or clinical signs alone. Thus, the DDS system proved valuable when the CRS system based on radiographic/clinical manifestations failed, the most significant finding being subclinical histological manifestations of DI in patients with OI but without clinical or radiographic signs of DI. These subtle dysplastic changes are most likely an expression of genetic disturbances associated with OI and should not be diagnosed as DI, but rather be termed histologic manifestations of dysplastic dentin associated with OI.

  1. Odontoblast-targeted Bcl-2 Overexpression Promotes Dentin Damage Repair

    Science.gov (United States)

    Zhang, Wenjian; Ju, Jun

    2011-01-01

    Objective Bcl-2 is widely expressed in a developing tooth organ and regulates tooth morphogenesis. However, whether Bcl-2 is related to tooth damage repair is unknown yet. Using an odontoblast-targeted Bcl-2 overexpression transgenic mouse (Col2.3Bcl-2) and artificial cavity preparation as a model system, the relationship between Bcl-2 and reparative dentinogenesis is investigated in this study. Methods The odontoblastic-like cell cultures derived from mouse molar pulps were established. The expression of transgenic human Bcl-2 (hBcl-2) and endogenous mouse Bcl-2 (mBcl-2) and mouse Bax (mBax, a Bcl-2 antagonist) was detected in vivo and in vitro by Western blot and immunocytochemistry, respectively. Basal level and artificial cavity-induced odontoblast apoptosis was detected by the Deoxynucleotidyl Transferase (TdT) dUTP Nick End labeling (TUNEL) technique. Reparative dentin formation induced by artificial cavity drilled to a half dentin thickness on mesial cervical region of mandibular first molars 2, 4, and 6 weeks post-op was evaluated histologically and via micro-CT. Results The transgenic hBcl-2 was stably expressed in odontoblasts of the transgenic animals without interference with the expression of mBcl-2 and mBax. Basal level as well as artificial cavity- induced odontoblast apoptosis was prevented by the transgene. Compared to the wild type, the transgenic animals produced reparative dentin with significantly higher mineral density 6 weeks after the operation. Conclusions Bcl-2 overexpression prevents odontoblast apoptosis and promotes dentin damage repair, indicating that genetic manipulation of Bcl-2 may be a novel strategy to maintain the vitality and function of dentine-pulp complex under detrimental mechanical stimuli. PMID:21930259

  2. Dentin infiltration ability of different classes of adhesive systems.

    Science.gov (United States)

    Langer, Alina; Ilie, Nicoleta

    2013-01-01

    This study evaluates the dentin infiltration ability of various types of adhesives and compares four classes of adhesive systems with regard to this property. The infiltration is determined quantitatively, characterized as tag length and ratio of infiltration, and qualitatively, characterized as homogeneity, regularity, and continuity of the resin tags. Flat dentin surfaces from 140 halves of caries-free molars were bonded with four classes of adhesive systems. The adhesives (n = 20) were labeled with rhodamine B isothiocyanate and applied on the occlusal dentin following the manufacturer's recommendations and were subsequently light cured, 20 s. Then a 2-mm thick composite layer was applied and light cured, 20 s. The specimens were stored in distilled water at 37°C, 24 h. Two slices were sectioned mesio-distally from each sample and were investigated with a confocal laser scanning microscope. The measurements were done at 0.5, 1.5, and 2.5 mm from the enamel-dentin junction. The data were analyzed by using analysis of variance and the general linear model. The class of adhesive, the composition, and the dentin position were significant factors affecting the investigated parameters. The use of etch and rinse adhesives in comparison to self-etch adhesives provided the formation of longer, more homogeneous, very regularly distributed but mostly fractured tags. A comparison of adhesives confirmed that etch and rinse systems remain better in bond infiltration. While the importance of tags formation on bonding is still controversially discussed, adhesive systems with a high ratio of infiltration might better protect the tooth against microorganism contamination.

  3. Meta-analytical review of factors involved in dentin adherence.

    Science.gov (United States)

    Leloup, G; D'Hoore, W; Bouter, D; Degrange, M; Vreven, J

    2001-07-01

    Literature data on adherence tests of dentin-bonding systems (DBS) may differ widely, even for the same DBS. The problem of bond testing is that materials are seldom compared with a standard, and experimental conditions often vary. We sought to identify the parameters that influence this variability. Using inclusion and exclusion criteria, we conducted a meta-analytical review of 75 articles, published between 1992 and 1996 in SCI reviews, that give bond strength data for 15 dentin-bonding agents of the so-called third and fourth generations. Seventeen selected parameters were classified into four groups: Group A includes factors related to the dentin substrate (i.e., nature of teeth); group B, composite and bonding area (i.e., composite stiffness); group C, storage conditions of the bonded samples (i.e., thermocycling); and group D, test design (i.e., crosshead speed). For each report, the experimental features, the bond strength means and standard deviations, and the failure mode were extracted and tabulated. Statistical Analysis System software was used to perform Pearson correlation analysis and analysis of variance, with bond strength as the dependent variable and experimental conditions as the independent variables. The meta-analytical review highlighted the significant influence of various parameters in the different groups: origin of dentin, types of teeth, pulpal pressure, tooth storage temperature, maximum storage time of teeth, and dentin depth in group A; type and stiffness of composite and bonding area in group B; storage of bonded samples (medium, temperature, and time) in group C, and testing mode and crosshead speed in group D. A significant positive correlation was observed between the mean bond strength and the rate of cohesive failure. It can be concluded from this study that some of these parameters should be controlled by the use of a standardized protocol. Unfortunately, the substrate-related variables are more difficult to control, even

  4. Uncontrolled Removal of Dentin during In Vitro Ultrasonic Irrigant Activation.

    Science.gov (United States)

    Boutsioukis, Christos; Tzimpoulas, Nestor

    2016-02-01

    The aim of this study was to evaluate uncontrolled removal of dentin during in vitro ultrasonic irrigant activation in prepared root canals using 2 different files. Fifty-four human single-rooted teeth with straight root canals were prepared to size 35/.06 taper. The specimens were randomly allocated to 3 groups (n = 18). Two milliliters of 2% sodium hypochlorite was delivered 3 times to each root canal by a syringe and an open-ended needle. After each delivery, the irrigant was ultrasonically activated for 10 seconds at 35% power either by a size 15 ultrasonic K-file (group A) or a size 20 Irrisafe file (Acteon Satelec, Merignac, France) (group B) placed at 2 mm short of the working length. The irrigant in the control specimens (group C) was not activated. Specimens were scanned by micro-computed tomographic imaging at 10-μm voxel size before preparation, after preparation, and after the final irrigation/activation sequence. Scans were coregistered and segmented, and the amount of dentin removed during the final step was quantified by morphologic operations. Results were analyzed by nonparametric statistical tests. The level of significance was set to P ultrasonic files removed significantly more dentin than irrigant delivery in the control group (P ≤ .005). K-files removed significantly more dentin than Irrisafe files in the apical third (P = .001). Ultrasonic irrigant activation may result in uncontrolled removal of dentin in straight root canals and at manufacturer-recommended power settings. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  5. Enhancement of nano-hydroxyapatite bonding to dentin through a collagen/calcium dual-affinitive peptide for dentinal tubule occlusion.

    Science.gov (United States)

    Wang, Ronghan; Wang, Qiong; Wang, Xiumei; Tian, Lili; Liu, Huiying; Zhao, Miaomiao; Peng, Ce; Cai, Qiang; Shi, Yunming

    2014-08-01

    Calcium phosphate crystals, as the main component of dentin and enamel, have been widely used for the occlusion of dentinal tubules. However, the low bond strength and poor sealing effect limit their clinical practicality. In this study, a collagen/calcium dual-affinitive peptide E8DS (EEEEEEEEDSpESpSpEEDR) and nano-hydroxyapatite (nano-HAp) flocculi were developed to seal dentin tubules for reducing dentin hypersensitivity, whereas the E8DS peptides were pre-applied to improve the adhesion of occlusive hydroxyapatite coating on dentin collagen matrix for the long-lasting sealing effect and relief from hypersensitivity. Our study showed that E8DS peptides had a strong affinity with dentin collageneous matrix that almost 43.7% of initial E8DS peptides immobilized on exposed dentin samples remained detained after continuous washing by distilled water for four weeks at a rate of 1 mL/min. Nano-HAp flocculi were obtained by re-neutralization of HAp-HCl solution and then brushed onto the surfaces of pre-treated human dentin disks with E8DS peptides, which showed a perfect occlusion of exposed dentinal tubules, as compared with Nano-HAp only and a commercial desensitizer, Green Or. With only around 10-min E8DS peptide pre-treatment, the occlusive mineral layers remained intact against consecutively stirred washing in phosphate-buffered saline or coke for 15 min, and 6 min of tooth-brushing, which implied that our E8DS peptide could comparatively improve the durability of sealant-dentin interface bonds for long-lasting dentine desensitization. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  6. Marginal adaptation of class V restorations with current-generation dentin-bonding agents: effect of different dentin surface treatments.

    Science.gov (United States)

    Cavalheiro, Jessica Patrícia; Tonetto, Mateus Rodrigues; Borges, Álvaro Henrique; Bandéca, Matheus Coelho; dos Santos, Reidson Stanley Soares; de Campos, Edson Alves; Saad, José Roberto Cury; Dantas, Andréa Abi Rached; de Andrade, Marcelo Ferrarezi

    2014-05-01

    This study sought to assess the use of chlorhexidine with several excipients as a dentin surface treatment and its effect on marginal adaptation of class V restorations with current-generation dentin bonding agents. A total of 120 human third molars were selected and allocated into 12 groups, with standardized buccal class V restorations randomly divided into preconditioned dentin rinsed with: water; water + chlorhexidine; ethanol; or ethanol + chlorhexidine. After rinsing of dentin (previously conditioned with 35% phosphoric acid) with the test solutions, the Adper single bond 2, prime and bond 2.1, and Excite bonding systems were applied randomly. Restorations were performed with Filtek™ Z350 XT composite resin. The resulting specimens were subjected to thermal and mechanical load cycling. Quantitative analysis of marginal adaptation was performed on epoxy replicas by means of scanning electron microscopy. Results were assessed by means of the Kruskal-Wallis test (percentages of continuous margins) and Wilcoxon test (differences between percentages of continuous margins before and after thermal cycling and mechanical loading), at a significance level of p < 0.05. Outcomes in the chlorhexidine-treated groups were not superior to those obtained with other treatments.

  7. Differences in the pattern of lanthanum diffusion into predentine and dentine in mouse incisors and molars.

    Science.gov (United States)

    Torres-Quintana, M A; Septier, D; Goldberg, M

    1999-04-01

    Lanthanum nitrate was either perfused intravascularly or segments of mouse tooth were immersed in a fixative solution containing the tracer. The tracer deposits were examined in young (8-day-old) and older (8-week-old) mouse incisors and molars, demineralized or undemineralized. Lanthanum passed the distal junctional complex of odontoblasts and appeared in the predentine of incisors as large electron-dense stellate aggregates, 40-70 nm in diameter, and in molars as round, 20-40 nm dots. In dentine, tracer deposits were detected at three locations. Near the predentine dentine junction, the tracer densely stained a band 0.5-2.5 microm in width, also termed metadentine; in the inner circumpulpal dentine, the staining was weaker or lacking in an area extending 5-7 microm from the predentine-dentine junction; in outer circumpulpal dentine, lateral diffusion had occurred in porosities of intertubular dentine. Lanthanum impregnated the walls of dentine tubules and a peritubular-like dentine. In contrast, the mantle dentine was never stained. These differences in the pattern of diffusion prove that lanthanum staining is age-dependent and varies between mouse incisors and molars, independently of tissue processing. Architectural properties and driving flux are involved in the transport and localization of lanthanum in predentine and dentine.

  8. Effect of 2-(methacryloxy)ethyl phenyl hydrogen phosphate on adhesion to dentin.

    Science.gov (United States)

    Wang, T; Nakabayashi, N

    1991-01-01

    A variety of methacrylate-based materials has been developed with the capacity of adhering to dentin. This study investigated the effectiveness of 2-(methacryloxy)ethyl phenyl hydrogenphosphate (phenyl-P) for bonding 5% phenyl-P in methyl methacrylate (MMA) to dentinal surfaces. Polymerization of the phenyl-P/MMA monomer was initiated by partially oxidized tri-n-butyl borane catalyst (TBB). The mean tensile bond strength of 5% phenyl-P in MMA to dentin that was pre-treated with an aqueous solution of 10% citric acid/3% ferric chloride, abbreviated as 10-3, was found to be 10.5 MPa. Scanning electron microscope examination demonstrated the formation of a transitional or "hybrid" layer of resin-reinforced dentin, created by the intermingling and entanglement of polymerized resin with collagen bundles exposed by dentin pre-treatment with 10-3, an effective remover of the dentinal smear layer. This "hybrid" layer or zone was essential for high tensile bond strength to be attained. Phenyl-P was found to be effective in promoting monomer diffusion and impregnating monomer into demineralized dentinal surfaces. The formation of the "hybrid" layer of resin-reinforced dentin followed in situ resin polymerization initiated by partially oxidized tri-n-butyl borane (TBB). Ferric (Fe3+) ions deposited on dentinal surfaces from the 10-3 solution also acted to improve monomer diffusion and entanglement with demineralized dentin, and facilitated the formation of the "hybrid" layer/zone.

  9. Calcium phosphates produced by physical methods in the treatment of dentin hypersensitivity.

    Science.gov (United States)

    Dolci, G; Mongiorgi, R; Prati, C; Valdrè, G

    1999-10-01

    The aim of this paper is to study the properties of innovative materials based on defective calcium phosphates produced by physical methods in the therapy of dentin hypersensitivity. In particular, the effects of gels, aqueous solutions and toothpastes containing the above mentioned materials on dentinal permeability measured as dentin hydraulic conductance have been studied. The calcium phosphates have been characterized by X-ray powder diffraction (Rietveld analysis) and Fourier transform infra-red analysis. In addition, scanning electron microscopy has been performed to study the surface of dentin and enamel after treatment with the phosphates. In particular sound occlusal dentin, sound cervical dentin, carious occlusal dentin, sound buccal enamel and carious buccal enamel have been observed. The results have shown that these biocompatible materials can be produced with chemical and physical characteristics very similar to dentin and/or enamel. By forming a protective layer inside and outside the dentin tubuli, the calcium phosphates significantly reduce the dentinal hypersensitivity. These phosphates seem to be a promising material for clinical application.

  10. Dentin reactions to caries are misinterpreted by histological “gold standards”

    Science.gov (United States)

    Silva, Priscila Florentino; de Holanda Ferreira, Danilo Augusto; Meira, Kássia Regina Simões; Forte, Franklin Delano Soares; Chaves, Ana Maria Barros; de Sousa, Frederico Barbosa

    2014-01-01

    Dentin reactions to caries, crucial for pathogenesis and for the determination of the severity of caries lesions, are believed to be reasonably detected by stereomicroscopy (SM) and polarized light microscopy in quinoline (PLMQ), but accuracies are not available. Here, stereomicroscopy of wet (SW) and dry (SD) ground sections of natural occlusal caries lesions resulted in moderate (0.7, for normal dentin) and low accuracies (dentin) as validated by contrast-corrected microradiography. Accuracies of PLMQ were moderate for both normal (0.71) and carious dentin (0.71). The hypothesis that detection of dentin reactions by SM and PLMQ would be influenced by the contrast quality of micrographic images was rejected. Dentin reactions were scored by SW, SD, PLMQ, and three types of microradiographic images with varying contrast qualities and each technique was compared against the one that resulted in the highest number of scores for each dentin reaction. Large differences resulted, mainly related to the detection of sclerotic dentin by both SW and SD, and normal and carious dentin by PLMQ. It is concluded that contrast-corrected microradiography should be preferred as the gold standard and SM and PLMQ should be avoided, but the relationship of PLMQ with dentin mineralization deserves further investigation. PMID:25469227

  11. Evaluating EDTA as a substitute for phosphoric acid-etching of enamel and dentin.

    Science.gov (United States)

    Imbery, Terence A; Kennedy, Matthew; Janus, Charles; Moon, Peter C

    2012-01-01

    Matrix metalloproteinases (MMPs) are proteolytic enzymes released when dentin is acid-etched. The enzymes are capable of destroying unprotected collagen fibrils that are not encapsulated by the dentin adhesive. Chlorhexidine applied after etching inhibits the activation of released MMPs, whereas neutral ethylenediamine tetra-acetic acid (EDTA) prevents the release of MMPs. The purpose of this study was to determine if conditioning enamel and dentin with EDTA can be a substitute for treating acid-etching enamel and dentin with chlorhexidine. A column of composite resin was bonded to enamel and dentin after conditioning. Shear bond strengths were evaluated after 48 hours and after accelerated aging for three hours in 12% sodium hypochlorite. Shear bond strengths ranged from 15.6 MP a for accelerated aged EDTA enamel specimens to 26.8 MPa for dentin conditioned with EDTA and tested after 48 hours. A three-way ANOVA and a Tukey HSD test found statistically significant differences among the eight groups and the three independent variables (P dentin treated with chlorhexidine. Interactions of conditioning agent and aging were significant for dentin but not for enamel. In an effort to reduce the detrimental effects of MMPs, conditioning enamel and dentin with EDTA is an alternative to treating acid-etched dentin and enamel with chlorhexidine.

  12. In vivo model for microbial invasion of tooth root dentinal tubules

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    Jane L. BRITTAN

    2016-04-01

    Full Text Available ABSTRACT Objective Bacterial penetration of dentinal tubules via exposed dentine can lead to root caries and promote infections of the pulp and root canal system. The aim of this work was to develop a new experimental model for studying bacterial invasion of dentinal tubules within the human oral cavity. Material and Methods Sections of human root dentine were mounted into lower oral appliances that were worn by four human subjects for 15 d. Roots were then fixed, sectioned, stained and examined microscopically for evidence of bacterial invasion. Levels of invasion were expressed as Tubule Invasion Factor (TIF. DNA was extracted from root samples, subjected to polymerase chain reaction amplification of 16S rRNA genes, and invading bacteria were identified by comparison of sequences with GenBank database. Results All root dentine samples with patent tubules showed evidence of bacterial cell invasion (TIF value range from 5.7 to 9.0 to depths of 200 mm or more. A spectrum of Gram-positive and Gram-negative cell morphotypes were visualized, and molecular typing identified species of Granulicatella, Streptococcus, Klebsiella, Enterobacter, Acinetobacter, and Pseudomonas as dentinal tubule residents. Conclusion A novel in vivo model is described, which provides for human root dentine to be efficiently infected by oral microorganisms. A range of bacteria were able to initially invade dentinal tubules within exposed dentine. The model will be useful for testing the effectiveness of antiseptics, irrigants, and potential tubule occluding agents in preventing bacterial invasion of dentine.

  13. The effect of MTA application on the affected dentine remineralization after partial caries excavation (in vivo)

    Science.gov (United States)

    Pratiwi, A. R.; Meidyawati, R.; Djauharie, N.

    2017-08-01

    On deep carious lesions, only thin dentine remains, causing a high risk of pulp exposure during the removal of all infected dentine. A minimally invasive technique is required, such as a partial caries excavation method in the infected dentine tissue and the use of bioactive material that can promote (Mineral Trioxide Aggregate) MTA remineralization. To compare the remineralization of deep carious lesion-affected dentine with the removal of some and all the infected dentine after the application of MTA. Subjects were divided into two groups: group I had only some parts of the infected dentine removed before MTA application, while group II had all the infected dentine removed before MTA application. Each group was measured on the pixel grey value before the treatment and again four weeks after the MTA application, and then the results were compared. Furthermore, the enhancement of both groups’ grey values were compared. Remineralization occurred in both groups after the MTA application. There was no significant difference in the remineralization level of the affected dentine in both groups I and II four weeks after the MTA application. Remineralization occurred in the affected dentine in both groups, either by removing only some parts or all the infected dentine in the deep carious lesion.

  14. Temperature rise produced by different light-curing units through dentin.

    Science.gov (United States)

    Yazici, A Rüya; Müftü, Ali; Kugel, Gerard

    2007-11-01

    This study investigated the temperature rise caused by different light curing units and the temperature increase in dentin of different thicknesses. Dentin discs of 1.0 and 2.0 mm thicknesses were prepared from extracted human mandibular molars. Temperatures were recorded directly at the surface of the light guide tip, under dentin discs with different thicknesses, and through a sandwich composed of 2 mm thick cured composite and dentin using a K-type thermocouple. The curing units used were two quartz-tungsten-halogen lights (Spectrum and Elipar Trilight-ET) and a light-emitting diode (LED). The highest temperature rise was observed under a Mylar strip using ET standard mode. Under 1 and 2 mm thick dentin barriers, the lowest temperature rise was measured for the LED curing light. Significant differences in temperature rise existed among all curing units except between the Spectrum and ET exponential modes under a 1 mm thick dentin barrier with cured composite. Temperature rises were insignificant between the Spectrum and ET exponential modes and between two modes of Trilight when the same experimental setup was used under a 2 mm thick dentin barrier. For all curing units, temperature elevation through 2 mm of dentin was less than for 1 mm of dentin thickness. The ET standard mode produced the highest and the LED produced the lowest temperature rise for all tested conditions. The thickness of dentin and light-curing unit might affect temperature transmission.

  15. In vivo remineralization of dentin using an agarose hydrogel biomimetic mineralization system

    Science.gov (United States)

    Han, Min; Li, Quan-Li; Cao, Ying; Fang, Hui; Xia, Rong; Zhang, Zhi-Hong

    2017-02-01

    A novel agarose hydrogel biomimetic mineralization system loaded with calcium and phosphate was used to remineralize dentin and induce the oriented densely parallel packed HA layer on defective dentin surface in vivo in a rabbit model. Firstly, the enamel of the labial surface of rabbits’ incisor was removed and the dentin was exposed to oral environment. Secondly, the hydrogel biomimetic mineralization system was applied to the exposed dentin surface by using a custom tray. Finally, the teeth were extracted and evaluated by scanning electron microscopy, X-ray diffraction, and nanoindentation test after a certain time of mineralization intervals. The regenerated tissue on the dentin surface was composed of highly organised HA crystals. Densely packed along the c axis, these newly precipitated HA crystals were perpendicular to the underlying dental surface with a tight bond. The demineralized dentin was remineralized and dentinal tubules were occluded by the grown HA crystals. The nanohardness and elastic modulus of the regenerated tissue were similar to natural dentin. The results indicated a potential clinical use for repairing dentin-exposed related diseases, such as erosion, wear, and dentin hypersensitivity.

  16. In vitro study of caries detection through sound dentin using a laser fluorescence device, DIAGNOdent.

    Science.gov (United States)

    Iwami, Yukiteru; Shimizu, Ayako; Yamamoto, Hiroko; Hayashi, Mikako; Takeshige, Fumio; Ebisu, Shigeyuki

    2003-02-01

    The objective of this study was to investigate the feasibility of proximal surface caries detection using a laser fluorescence device, DIAGNOdent, through the sound dentin surrounding the cavity wall after removal of occlusal caries. Extracted sound human molars were ground to prepare horizontal and vertical dentin plates 1.4 mm thick. Extracted carious human molars were reduced in thickness horizontally from the occlusal surfaces until exposure of the dentin caries. The dentin plate was placed on the carious tooth. Before and after gradual thinning of the dentin plate from approximately 1.4 mm to 0.2 mm thick, the dentin caries was measured 10 times through the plate by the laser fluorescence device with a cone-shaped tip or a broad tip. When the dentin plate was reduced to less than 0.3 mm thick (using a combination of a horizontal plate and cone-shaped tip) or 0.2 mm thick (using the other combinations), the values measured with the laser fluorescence device were significantly larger than the values before reducing the thickness of the dentin. Based on these results, the device offers potential use as one of the screening tests for proximal surface caries detection through sound dentin when the sound dentin between tip and caries is thin.

  17. Tooth root dentin mineralization defects in a mouse model of hypophosphatasia.

    Science.gov (United States)

    Foster, B L; Nagatomo, K J; Tso, H W; Tran, A B; Nociti, F H; Narisawa, S; Yadav, M C; McKee, M D; Millán, J I; Somerman, M J

    2013-02-01

    Tissue-nonspecific alkaline phosphatase (TNAP) is expressed in mineralizing tissues and functions to reduce pyrophosphate (PP(i) ), a potent inhibitor of mineralization. Loss of TNAP function causes hypophosphatasia (HPP), a heritable disorder marked by increased PP(i) , resulting in rickets and osteomalacia. Tooth root cementum defects are well described in both HPP patients and in Alpl(-/-) mice, a model for infantile HPP. In Alpl(-/-) mice, dentin mineralization is specifically delayed in the root; however, reports from human HPP patients are variable and inconsistent regarding dentin defects. In the current study, we aimed to define the molecular basis for changes in dentinogenesis observed in Alpl(-/-) mice. TNAP was found to be highly expressed by mature odontoblasts, and Alpl(-/-) molar and incisor roots featured defective dentin mineralization, ranging from a mild delay to severely disturbed root dentinogenesis. Lack of mantle dentin mineralization was associated with disordered and dysmorphic odontoblasts having disrupted expression of marker genes osteocalcin and dentin sialophosphoprotein. The formation of, initiation of mineralization within, and rupture of matrix vesicles in Alpl(-/-) dentin matrix was not affected. Osteopontin (OPN), an inhibitor of mineralization that contributes to the skeletal pathology in Alpl(-/-) mice, was present in the generally unmineralized Alpl(-/-) mantle dentin at ruptured mineralizing matrix vesicles, as detected by immunohistochemistry and by immunogold labeling. However, ablating the OPN-encoding Spp1 gene in Alpl(-/-) mice was insufficient to rescue the dentin mineralization defect. Administration of bioengineered mineral-targeting human TNAP (ENB-0040) to Alpl(-/-) mice corrected defective dentin mineralization in the molar roots. These studies reveal that TNAP participates in root dentin formation and confirm that reduction of PP(i) during dentinogenesis is necessary for odontoblast differentiation, dentin matrix

  18. Relationship between the color of carious dentin with varying lesion activity, and bacterial detection.

    Science.gov (United States)

    Iwami, Yukiteru; Hayashi, Norifumi; Takeshige, Fumio; Ebisu, Shigeyuki

    2008-02-01

    To investigate the relationship between the color of carious dentin with varying lesion activity, and bacterial detection in the lesions. In 26 extracted human molars with coronal dentin caries and four extracted sound human molars, dentin was removed by a round bur every 150 microm from the dentin surface, in the direction of the pulp chamber. Before and after removal, images of nine-color samples and the dentin surface stained with a caries detector dye (1% acid red in propylene glycol) were taken simultaneously by a charge-coupled device (CCD), and dentinal tissue samples were taken with a new round bur. From the images, corrected L*, a* and b* values (CIE 1976 L*a*b* color system) of the dentin surfaces were calculated from the color changes of the nine-color samples. Bacterial DNA in the dentinal tissues was detected by polymerase chain reaction. Before removal of dentin, the L* of sound molars (L*>50) was significantly larger than that of carious molars (L*type I (a*>20, characteristics of active caries) and type II (a*types, the area under the receiver operating characteristic curve of L* was significantly larger than that of a* or b* (univariate Z score test, Pdentinal tissue increased, and bacterial DNA was not detected when L* was >60. Sound and types I and II carious dentin were discriminated by the combination of L* and a* values of dentinal tissue stained with the caries detector dye before removal of dentin. In carious lesions, the a* values of carious dentin stained with the dye were related to the carious lesion activity before removal of carious tissue, and the L* values were related to the degree of caries progression.

  19. The effect of acid etchant type and dentin location on tubular density and dimension.

    Science.gov (United States)

    Caiado, Ana Carolina Rocha Lima; de Goes, Mario Fernando; de Souza-Filho, Francisco José; Rueggeberg, Frederick A

    2010-06-01

    Coronal and radicular dentin may react differently to the type of acid treatment used when bonding to these substrates. The purpose of this study was to characterize and compare dentin morphology, tubular density, and cross-sectional area in deep coronal (around an exposed pulp horn) and root canal dentin at the cervical third in the intact state and after acid etching with phosphoric acid or self-etching dentin primer. Extracted, human, caries-free premolars were fixed. Smear layer-free sections (control) were obtained and divided into 3 groups: left intact, etched with phosphoric acid, or etched with a self-etching primer from a dentin bonding system. Specimens were examined using scanning electron microscopy. Tubular density and cross-sectional area were determined from the images using software. Values were submitted to multifactorial ANOVA (alpha=.05). Tubular density was not significantly affected by acid type or by dentin location. Acid type significantly (P self-etching resin > intact dentin, irrespective of dentin location. All acid-treated specimens showed demineralization, and irregular surface morphology was not affected by either acid treatment. Tubular density was not significantly different between deep coronal and root canal dentin nor affected by acid treatment type. Tubular cross-sectional area did not differ between deep coronal or root canal dentin, regardless of acid treatment. Both acid types significantly increased tubular cross-sectional area at both dentin locations, phosphoric acid to a greater degree than the self-etching primer. Root canal dentin did not display peritubular dentin. Copyright 2010 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

  20. Combining Bioactive Multifunctional Dental Composite with PAMAM for Root Dentin Remineralization

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    Shimeng Xiao

    2017-01-01

    Full Text Available Objectives. The objectives of this study were to: (1 develop a bioactive multifunctional composite (BMC via nanoparticles of amorphous calcium phosphate (NACP, 2-methacryloyloxyethyl phosphorylcholine (MPC, dimethylaminohexadecyl methacrylate (DMAHDM and nanoparticles of silver (NAg; and (2 investigate the effects of combined BMC + poly (amido amine (PAMAM on remineralization of demineralized root dentin in a cyclic artificial saliva/lactic acid environment for the first time. Methods. Root dentin specimens were prepared and demineralized with 37% phosphoric acid for 15 s. Four groups were prepared: (1 root dentin control; (2 root dentin with BMC; (3 root dentin with PAMAM; (4 root dentin with BMC + PAMAM. Specimens were treated with a cyclic artificial saliva/lactic acid regimen for 21 days. Calcium (Ca and phosphate (P ion concentrations and acid neutralization were determined. The remineralized root dentin specimens were examined via hardness testing and scanning electron microscopy (SEM. Results. Mechanical properties of BMC were similar to commercial control composites (p = 0.913. BMC had excellent Ca and P ion release and acid-neutralization capability. BMC or PAMAM alone each achieved slight mineral regeneration in demineralized root dentin. The combined BMC + PAMAM induced the greatest root dentin remineralization, and increased the hardness of pre-demineralized root dentin to match that of healthy root dentin (p = 0.521. Significance. The excellent root dentin remineralization effects of BMC + PAMAM were demonstrated for the first time. BMC + PAMAM induced effective and complete root dentin remineralization in an acid challenge environment. The novel BMC + PAMAM method is promising for Class V and other restorations to remineralize and protect tooth structures.

  1. Remineralization potential of fully demineralized dentin infiltrated with silica and hydroxyapatite nanoparticles.

    Science.gov (United States)

    Besinis, Alexandros; van Noort, Richard; Martin, Nicolas

    2014-03-01

    This study investigates the potential of a novel guided tissue regeneration strategy, using fully demineralized dentin infiltrated with silica and hydroxyapatite (HA) nanoparticles (NPs), to remineralize dentin collagen that is completely devoid of native hydroxyapatite. Dentin blocks were fully demineralized with 4N formic acid and subsequently infiltrated with silica and HA NPs. The remineralizing potential of infiltrated dentin was assessed following a twelve week exposure to an artificial saliva solution by means of TEM, EDS and micro-CT. Measurements were taken at baseline and repeated at regular intervals for the duration of the study to quantify the P and Ca levels, the mineral volume percentage and mineral separation of the infiltrated dentin specimens compared to sound dentin and non-infiltrated controls. Infiltration of demineralized dentin with nano-HA restored up to 55% of the P and Ca levels at baseline. A local increase in the concentration of calcium phosphate compounds over a period of twelve weeks resulted in a higher concentration in P and Ca levels within the infiltrated specimens when compared to the non-infiltrated controls. Remineralization of demineralized dentin with silica NPs by immersion in artificial saliva was the most effective strategy, restoring 20% of the P levels of sound dentin. Micro-CT data showed a 16% recovery of the mineral volume in dentin infiltrated with silica NPs and a significant decrease in the mineral separation to levels comparable to sound dentin. Demineralized dentin infiltrated with silica NPs appears to encourage heterogeneous mineralization of the dentin collagen matrix following exposure to an artificial saliva solution. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  2. SOLIDARIEDADE E APARÊNCIA DE SOLIDARIEDADE: A IRONIA NO CONTO “A CAUSA SECRETA”

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    Daniela Freitas Torres

    2008-11-01

    Full Text Available Este estudo analisa o conto “A causa secreta”, de Machado de Assis, cujo enredo gira em torno do personagem Fortunato, que se mostra uma figura muito solidária perante os outros, mas na verdade, essa abnegação revela-se como uma grande ironia ao longo do texto. Aborda primeiramente, a questão da solidariedade sob o prisma de diferentes visões, desde o conceito cristão até algumas abordagens da sociedade atual para esse assunto, observando a presença desse sentimento nas ações do personagem Fortunato. A seguir, é colocado em pauta o tema ironia e sua presença na literatura, bem como suas implicações na obra machadiana e, em especial, no conto estudado. Posteriormente, apresenta-se uma breve abordagem sobre sadismo, seus conceitos e sua relação com a “causa secreta” presente no conto. A partir daí estuda-se a relação entre a questão de a solidariedade ser apenas uma aparência, utilizada para esconder o sadismo, que seria o elemento central da constituição psicológica do personagem Fortunato. Para concluir, mostram-se as reflexões possíveis em relação à condição humana que podem ser proporcionadas a partir da leitura de “A causa secreta”, evidenciando a incompletude humana que, sendo reconhecida e aceita pelo leitor, poderá levar a um trabalho de autoconhecimento.

  3. Fadiga óssea: causa de dor em joelhos na osteoartrite

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    Wilson Campos Tavares Júnior

    2012-10-01

    Full Text Available A dor no joelho é o sintoma mais comum na osteoartrite, sendo a principal causa de incapacidade crônica em idosos e uma das principais fontes de morbidade atribuível à osteoartrite em geral. As causas de dor no joelho em pessoas com osteoartrite não são facilmente entendidas e o conhecimento sobre as causas da dor é fundamental para que futuramente sejam realizadas intervenções específicas. A fadiga óssea representa o remodelamento do osso subcondral na osteoartrite, levando a uma consequente alteração na forma do osso e/ou perda óssea. No entanto, a fadiga óssea não é algo facilmente interpretado, pois é de difícil detecção na ausência de defeitos claros da cortical e pela sobreposição de estruturas ósseas nas radiografias convencionais. A fadiga óssea está associada não apenas a dor no joelho, mas também a rigidez e incapacidade. Se a fadiga ocorre antes da osteoartrite avançada, isso sugere que alterações no osso subcondral podem ocorrer simultaneamente a alterações da cartilagem e que tratamentos visando sua preservação podem não ser eficazes. Lesões com padrão de edema ósseo estão associadas e são fatores preditivos para fadiga óssea. Este trabalho tem por objetivo rever a literatura mostrando a importância da fadiga óssea e de como diagnosticar esta alteração nos exames de imagem.

  4. Prevalencia y causas de ceguera en Perú: encuesta nacional

    OpenAIRE

    Betty Campos; Amelia Cerrate; Enrique Montjoy; Víctor Dulanto Gomero; César Gonzales; Aldo Tecse; Andrés Pariamachi; Van C. Lansingh; Víctor Dulanto Reinoso; Jean Minaya Barba; Juan Carlos Silva; Hans Limburg

    2014-01-01

    OBJETIVO: Estimar la prevalencia de ceguera y deficiencia visual en adultos de Perú y precisar sus causas, evaluar la cobertura y la calidad de los servicios de cirugía de catarata y determinar las barreras que impiden acceder a esos servicios. MÉTODOS: Estudio poblacional transversal con muestreo aleatorio por conglomerado en dos pasos de personas de 50 años o más, representativo de todo el país, mediante la metodología estándar de la Evaluación Rápida de Ceguera Evitable. Se midió la agudez...

  5. Violência, culpa e ato: causas e efeitos subjetivos em adolescentes

    OpenAIRE

    Henrique Figueiredo Carneiro; Colamoradores*

    2010-01-01

    Este trabalho apresenta um relato de pesquisa realizada sobre a violência e o adolescente, evidenciando o objetivo, as causas e os efeitos subjetivos que desencadeiam a violência na atualidade. Apresenta também uma investigação qualitativa com referencial teórico-conceitual da psicanálise, em destaque os conceitos de mal-estar, lei, anomia, limites, laços sociais, necessidade, desejo, culpa, passagem ao ato, individualismo, discurso capitalista, amor, vida e morte. Foram utilizados fotografia...

  6. Causas de estrés académico en estudiantes universitarios

    OpenAIRE

    Arias-Gundín, O.; Vizoso-Gómez, C.M.

    2016-01-01

    Los estudiantes universitarios tienen que afrontar determinadas situaciones académicas que representan un reto difícil de superar. En ocasiones, los estudiantes perciben que las demandas que requieren estas situaciones sobrepasan los recursos de los que disponen, convirtiéndose así en fuentes de estrés académico. En esta investigación se pretende analizar cuáles son las principales situaciones percibidas con más frecuencia como causa de estrés académico en estudiantes universitarios y, además...

  7. La reticencia a hablar en las aulas de ELE en Corea. Un acercamiento a sus causas

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    Mendoza Puertas, Jorge Daniel

    2016-03-01

    Full Text Available La baja participación de los estudiantes de Asia oriental en las clases de lenguas extranjeras ha sido constatada por diversos investigadores. En este trabajo ofrecemos un estudio de carácter cualitativo basado en entrevistas, grupos de discusión y anotaciones realizadas en un diario de trabajo. A través de sus resultados pretendemos ofrecer luz acerca de las causas sobre las que descansa la reticencia a hablar de los estudiantes coreanos en las aulas universitarias de español como lengua extranjera.

  8. Las Causas que Llevan a la Infidelidad: Un Análisis por Sexo

    OpenAIRE

    José Luis Valdez Medina

    2013-01-01

    El objetivo fue detectar las causas que llevan con más frecuencia a los hombres y las mujeres a presentar la conducta de infidelidad. Para ello, se trabajó con una muestra no probabilística de tipo intencional, compuesta por 75 parejas de casados y 75 parejas de solteros en una relación de noviazgo, residentes de la Ciudad de Toluca, bajo la condición de haber cometido una infidelidad hacia su pareja. Una vez obtenido el consentimiento de cada participante, las aplicaciones con previa cita, s...

  9. Las causas que llevan a la infidelidad: Un análisis por sexo

    OpenAIRE

    Valdez Medina,José Luis; Colín, Beatriz González; Maya Martínez,Mario Ulises; Montes de Oca, Yessica Paola Aguilar; Arratia López Fuentes, Norma Ivonne González; Torres Muñoz, Martha Adelina

    2013-01-01

    El objetivo fue detectar las causas que llevan con más frecuencia a los hombres y las mujeres a presentar la conducta de infidelidad. Para ello, se trabajó con una muestra no probabilística de tipo intencional, compuesta por 75 parejas de casados y 75 parejas de solteros en una relación de noviazgo, residentes de la Ciudad de Toluca, bajo la condición de haber cometido una infidelidad hacia su pareja. Una vez obtenido el consentimiento de cada participante, las aplicaciones con previa cita, s...

  10. Artropastia total da anca dolorosa sem sinais de instabilidade : causas e tratamento

    OpenAIRE

    Viana, Luís Filipe Fernandes Jorge Santos

    2014-01-01

    Trabalho final de mestrado integrado em Medicina (Ortopedia), apresentado á Faculdade de Medicina da Universidade de Coimbra Introdução: A coxartrose representa uma das causas mais frequentes de incapacidade nas populações ocidentais. Dentre as diversas modalidades de tratamento, a artroplastia total da anca (ATA) é a intervenção de maior sucesso, porque permite o restabelecimento precoce da função articular e o alívio/supressão da dor. No entanto, alguns pacientes desenvolvem dor crónica ...

  11. Mortalidade por causas relacionadas ao aborto no Brasil: declínio e desigualdades espaciais

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    Lima Bruno Gil de Carvalho

    2000-01-01

    Full Text Available Além de constituir causa freqüente de internamentos obstétricos em países pobres, o aborto representa a incapacidade do sistema público de saúde de prover informação suficiente sobre métodos contraceptivos para prevenir gestações em vez de interrompê-las. No Brasil, as altas taxas de utilização de serviços de saúde por abortamentos refletem as dificuldades persistentes de contracepção e planejamento familiar. Além disso, a mortalidade por aborto serve como indicador da qualidade dos procedimentos abortivos, um ponto importante num país onde tal prática é ilegal e, portanto, clandestinamente realizada. No presente estudo, analisamos as taxas de mortalidade por causas relacionadas ao aborto entre mulheres de 10 a 54 anos de idade, incluindo aquelas que morreram por abortamentos espontâneos e provocados, de 1980 a 1995, segundo região de residência. As informações utilizadas foram obtidas do banco de dados sobre mortalidade do Sistema Único de Saúde --Ministério da Saúde. Dados sobre população foram obtidos junto à Fundação Instituto Brasileiro de Geografia e Estatística. Estudaram-se 2 602 óbitos. Do total de óbitos, 15% foram devidos a aborto retido, aborto espontâneo e aborto induzido com indicação legalmente admitida. Oitenta e cinco por cento dos óbitos foram causados por aborto induzido sem indicação legalmente admitida e por aborto sem causa especificada. Os coeficientes de mortalidade por causas relacionadas ao aborto têm decrescido continuamente no Brasil, mas tais avanços têm-se distribuído desigualmente no país. A região que apresentou a menor queda na taxa (38% em 15 anos foi o Nordeste. As mulheres que morreram por aborto tiveram uma média de idade decrescente no período estudado.

  12. Mortalidade por causas relacionadas ao aborto no Brasil: declínio e desigualdades espaciais

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    Bruno Gil de Carvalho Lima

    2000-03-01

    Full Text Available Além de constituir causa freqüente de internamentos obstétricos em países pobres, o aborto representa a incapacidade do sistema público de saúde de prover informação suficiente sobre métodos contraceptivos para prevenir gestações em vez de interrompê-las. No Brasil, as altas taxas de utilização de serviços de saúde por abortamentos refletem as dificuldades persistentes de contracepção e planejamento familiar. Além disso, a mortalidade por aborto serve como indicador da qualidade dos procedimentos abortivos, um ponto importante num país onde tal prática é ilegal e, portanto, clandestinamente realizada. No presente estudo, analisamos as taxas de mortalidade por causas relacionadas ao aborto entre mulheres de 10 a 54 anos de idade, incluindo aquelas que morreram por abortamentos espontâneos e provocados, de 1980 a 1995, segundo região de residência. As informações utilizadas foram obtidas do banco de dados sobre mortalidade do Sistema Único de Saúde --Ministério da Saúde. Dados sobre população foram obtidos junto à Fundação Instituto Brasileiro de Geografia e Estatística. Estudaram-se 2 602 óbitos. Do total de óbitos, 15% foram devidos a aborto retido, aborto espontâneo e aborto induzido com indicação legalmente admitida. Oitenta e cinco por cento dos óbitos foram causados por aborto induzido sem indicação legalmente admitida e por aborto sem causa especificada. Os coeficientes de mortalidade por causas relacionadas ao aborto têm decrescido continuamente no Brasil, mas tais avanços têm-se distribuído desigualmente no país. A região que apresentou a menor queda na taxa (38% em 15 anos foi o Nordeste. As mulheres que morreram por aborto tiveram uma média de idade decrescente no período estudado.

  13. Prevalencia y causas de ceguera en Perú: encuesta nacional

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    Betty Campos

    2014-11-01

    Full Text Available OBJETIVO: Estimar la prevalencia de ceguera y deficiencia visual en adultos de Perú y precisar sus causas, evaluar la cobertura y la calidad de los servicios de cirugía de catarata y determinar las barreras que impiden acceder a esos servicios. MÉTODOS: Estudio poblacional transversal con muestreo aleatorio por conglomerado en dos pasos de personas de 50 años o más, representativo de todo el país, mediante la metodología estándar de la Evaluación Rápida de Ceguera Evitable. Se midió la agudeza visual y se examinó el cristalino y el polo posterior por oftalmoscopía directa. Se calculó la cobertura de cirugía de catarata y se evaluó su calidad, además de las causas de tener una agudeza visual < 20/60 y las barreras para acceder a ese tratamiento. RESULTADOS:Se examinaron 4 849 personas. La prevalencia de ceguera fue 2,0% (intervalo de confianza de 95%: 1,5-2,5%. La catarata fue la causa principal de ceguera (58,0%, seguida por el glaucoma (13,7% y la degeneración macular relacionada con la edad (11,5%. Los errores de refracción no corregidos fueron la principal causa de deficiencia visual moderada (67,2%. La cobertura de cirugía de catarata fue de 66,9%, y 60,5% de los ojos operados de catarata logró una AV ≥ 20/60 con la corrección disponible. Las principales barreras para someterse a la cirugía de catarata fueron el alto costo (25,9% y no saber que el tratamiento es posible (23,8%. CONCLUSIONES: La prevalencia de ceguera y deficiencia visual en Perú es similar a la de otros países latinoamericanos. La baja cobertura de cirugía de catarata y el envejecimiento poblacional indican que para aumentar el acceso a estos servicios se debe mejorar la educación de la población en salud ocular y la capacidad resolutiva de los servicios oftalmológicos y de cirugía de catarata, y reducir su costo.

  14. CAUSAS DE LA SATISFACCIÓN LABORAL EN UNA ORGANIZACIÓN COMERCIALIZADORA MAYORISTA

    OpenAIRE

    PEDRO MANUEL ZAYAS AGÜERO; RAFAEL ANTONIO BÁEZ SANTANA; JOSUÉ ZAYAS FERIA; MARIANELA HERNÁNDEZ LOBAINA

    2015-01-01

    Este estudio tiene como objetivo determinar las causas que influyen en la satisfacción laboral en una comercializadora mayorista, permitiendo establecer las estrategias y las acciones para lograr un proceso de mejora continua de la organización. En la metodología se emplearon técnicas como: escalas, encuestas, entrevistas y observación directa, todas interrelacionadas, procediéndose a la triangulación de los resultados. Se validaron por expertos los instrumentos diseñados. El procesamiento ...

  15. The effect of a dentin desensitizer on the shear bond strength of composite to dentin using three different bonding agents: An in vitro study.

    Science.gov (United States)

    Mushtaq, Eeshan Arub; Mathai, Vijay; Nair, Rajesh Sasidharan; Angelo, JeyaBalaji Mano Christaine

    2017-01-01

    The effect of dentin desensitizer Systemp on the shear bond strength of composite resin to dentin using three different bonding agents, i.e., Prime & Bond NT, Xeno V(+), and Futurabond DC were evaluated. Sixty recently extracted human premolars were divided into six groups of ten teeth each. The superficial dentin was etched with 37% phosphoric acid. In Groups I, II, and III, Prime & Bond NT, Xeno V(+), and Futurabond DC, respectively, were applied to dentin and composite placed. Following application of dentin desensitizer Systemp in Groups IV, V, and VI, Prime & Bond NT, Xeno V(+), and Futurabond DC, respectively, were applied to dentin and composite placed. The shear bond strength was evaluated. Data obtained were statistically analyzed using one-way analysis of variance, post hoc, and Dunnett's test. Following application of dentin desensitizer Systemp, mean shear bond strength increased when Prime & Bond NT bonding agent was used while it decreased for Xeno V(+) and Futurabond DC bonding agents. Within the limitations of this in vitro study, it was observed that following application of dentin desensitizer Systemp, mean shear bond strength may increase or decrease depending on the bonding agents used.

  16. August 1936: terror and propaganda. The origins of the Causa General | Agosto de 1936: terror y propaganda. Los orígenes de la Causa General

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    Francisco Espinosa Maestre

    2005-12-01

    Full Text Available The propaganda battle began at the same time as the military coup of 18 July was tearing the country apart. In spite of the strict control of information deployed by the insurgents from the very beginning, the presence of foreign correspondents in that early period led to an outflow of pictures and reports that seriously damaged the image that those involved in the coup sought to project abroad. This is precisely what transpired in Badajoz in August 1936. Thus, the Nationalist propaganda machine launched an immediate campaign revealing Marxist atrocities, which bore fruit that same year with the so-called Avances del Informe Oficial, reports prepared in Seville which gave rise to the Causa General, the great legal process against the vanquished, decreed by Franco in April 1940. These advance reports encountered one major problem: the lack of bloodshed perpetrated by the Republican side in the southwest of Spain. | La batalla de la propaganda se inició al mismo tiempo que el golpe militar del 18 de julio desgarraba el país. A pesar del estricto control de la información que los sublevados ejercieron desde un principio, la presencia de corresponsales extranjeros provocó que en aquellos momentos iniciales pasasen al exterior imágenes y crónicas que dañaban seriamente la imagen que aquellos querían dar. Así ocurrió en Badajoz en agosto del 36. En consecuencia, el servicio de propaganda de los golpistas comenzó de inmediato una campaña mostrando los crímenes marxistas que dio sus primeros frutos en ese mismo año con los llamados Avances del Informe Oficial, informes que, gestados en Sevilla, constituyen realmente los orígenes de la Causa General, el gran proceso contra los vencidos decretado por Franco en abril de 1940. Dichos Avances sólo encontraron un problema: la insuficiente sangre derramada por los rojos en el suroeste español.

  17. Effectiveness and biological compatibility of different generations of dentin adhesives.

    Science.gov (United States)

    da Silva, João M F; Rodrigues, José R; Camargo, Carlos H R; Fernandes, Virgilio Vilas Boas; Hiller, Karl-Anton; Schweikl, Helmut; Schmalz, Gottfried

    2014-01-01

    Besides possessing good mechanical properties, dental materials should present a good biological behavior and should not injure the involved tissues. Bond strength and biocompatibility are both highly significant properties of dentin adhesives. For that matter, these properties of four generations of adhesive systems (Multi-Purpose/Single Bond/SE Plus/Easy Bond) were evaluated. Eighty bovine teeth had their dentin exposed (500- and 200-μm thickness). Adhesive was applied on the dentin layer of each specimen. Following that, the microshearing test was performed for all samples. A dentin barrier test was used for the cytotoxicity evaluation. Cell cultures (SV3NeoB) were collected from testing materials by means of 200- or 500-μm-thick dentin slices and placed in a cell culture perfusion chamber. Cell viability was measured 24 h post-exposition by means of a photometrical test (MTT test). The best bonding performance was shown by the single-step adhesive Easy Bond (21 MPa, 200 μm; 27 MPa, 500 μm) followed by Single Bond (15.6 MPa, 200 μm; 23.4 MPa, 500 μm), SE Plus (18.2 MPa, 200 μm; 20 MPa, 500 μm), and Multi-Purpose (15.2 MPa, 200 μm; 17.9 MPa, 500 μm). Regarding the cytotoxicity, Multi-Purpose slightly reduced the cell viability to 92% (200 μm)/93% (500 μm). Single Bond was reasonably cytotoxic, reducing cell viability to 71% (200 μm)/64% (500 μm). The self-etching adhesive Scotchbond SE decreased cell viability to 85% (200 μm)/71% (500 μm). Conversely, Easy Bond did not reduce cell viability in this test, regardless of the dentin thickness. Results showed that the one-step system had the best bond strength performance and was the least toxic to pulp cells. In multiple-step systems, a correct bonding technique must be done, and a pulp capping strategy is necessary for achieving good performance in both properties. The study showed a promising system (one-step self-etching), referring to it as a good alternative for specific cases, mainly due to its

  18. Localized mechanics of dentin self-etching adhesive system

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    Rodolfo Bruniera Anchieta

    2007-08-01

    Full Text Available The bond strength of composite resins (CRs to dentin is influenced by the interfacial microstructure of the hybrid layer (HL and the resin tags (TAG. The contemporary self-etching primer adhesive systems overcame the inconvenient of the etch-and-rinse protocol. Studies, however, have demonstrated that HL thickness and TAG length vary according to the wetting time and additional use of acid-etching prior to self-etching primers. This study investigated the localized stress distribution in the HL and the dentin/adhesive interface. Two HL thicknesses (3 or 6 µm, two TAG lengths (13 or 17 µm and two loading conditions (perpendicular and oblique-25º were investigated by the finite element (FE analysis. Five two-dimensional FE models (M of a dentin specimen restored with CR (38 x 64 µm were constructed: M1 - no HL and no TAG; M2 - 3 µm of HL and 13 µm of TAG; M3 - 3 µm of HL and 17 µm of TAG; M4 - 6 µm of HL and 13 µm of TAG; and M5 - 6 µm of HL and 17 µm of TAG. Two distributed loadings (L (20N were applied on CR surface: L1 - perpendicular, and L2 - oblique (25º. Fixed interfacial conditions were assigned on the border of the dentin specimen. Ansys 10.0 (Ansys®, Houston, PA, USA software was used to calculate the stress fields. The peak of von Mises (sigmavM and maximum principal stress (sigmamax was higher in L2 than in L1. Microstructures (HL and TAG had no effect on local stresses for L1. Decreasing HL decreased sigmavM and sigmamax in all structures for L2, but the TAG length had influence only on the peributular dentin. The thickness of HL had more influence on the sigmavM and sigmamax than TAG length. The peritubular dentin and its adjacent structures showed the highest sigmavM and sigmamax, mainly in the oblique loading.

  19. Dentin bonding-variables related to the clinical situation and the substrate treatment.

    Science.gov (United States)

    Perdigão, Jorge

    2010-02-01

    The wetness of dentin surfaces, the presence of pulpal pressure, and the thickness of dentin are extremely important variables during bonding procedures, especially when testing bond strength of adhesive materials in vitro with the intention of simulating in vivo conditions. The ultimate goal of a bonded restoration is to attain an intimate adaptation of the restorative material with the dental substrate. This task is difficult to achieve as the bonding process is different for enamel and for dentin-dentin is more humid and more organic than enamel. While enamel is predominantly mineral, dentin contains a significant amount of water and organic material, mainly type I collagen. This humid and organic nature of dentin makes this hard tissue very challenging to bond to. Several other substrate-related variables may affect the clinical outcome of bonded restorations. Bonding to caries-affected dentin is hampered by its lower hardness and presence of mineral deposits in the tubules. Non-carious cervical areas contain hypermineralized dentin and denatured collagen, which is not the ideal combination for a bonding substrate. Physiological transparent root dentin forms without trauma or caries lesion as a natural part of aging. Similar to the transparent dentin observed underneath caries lesions, the tubule lumina become filled with mineral from passive chemical precipitation, making resin hybridization difficult. An increase in number of tubules with depth and, consequently, increase in dentin wetness, make bonding to deeper dentin more difficult than to superficial dentin. While the application of acidic agents open the pathway for the diffusion of monomers into the collagen network, it also facilitates the outward seepage of tubular fluid from the pulp to the dentin surface, deteriorating the bonding for some of the current adhesives. Some dentin desensitizers have shown some promise as they can block dentinal tubules to treat and prevent sensitivity and simultaneously

  20. Coronal dentinal nodules induced by single or multiple injections of HEBP in young rats.

    Science.gov (United States)

    Brandsten, C; Alatli, I; Wurtz, T; Hammarström, L

    1995-01-01

    In the developing tooth, the bisphosphonate HEBP causes hypoplasias and hypomineralization of the enamel and dentine as well as inhibition of acellular cementum formation. Here, we describe a novel effect, associated with dentine mineralization. HEBP was administrated to young rats, and the maxillary molars were analyzed histologically. Localized dentinal nodules, protruding towards the pulp, were found in the developing crown of the molars. They occurred in regions, where the mantle dentine was about to mineralize at the time of the injection, and were more frequent at the mesial cusp side. The nodules accumulated mineral, as evidenced by the fluorescence after calcein and tetracyclin labelling. Histologically, the nodules were separated from the enamel by a layer of mantle dentine and were progressively surrounded by predentine and dentine. The nodules were interpreted to contain transport or metabolism intermediates, which were locally accumulated due to the interruption of the mineralization process by HEBP.

  1. Review of methyl methacrylate (MMA)/tributylborane (TBB)-initiated resin adhesive to dentin.

    Science.gov (United States)

    Taira, Yohsuke; Imai, Yohji

    2014-01-01

    This review, focusing mainly on research related to methyl methacrylate/tributylborane (MMA/TBB) resin, presents the early history of dentin bonding and MMA/TBB adhesive resin, followed by characteristics of resin bonding to dentin. Bond strengths of MMA/TBB adhesive resin to different adherends were discussed and compared with other bonding systems. Factors affecting bond strength (such as conditioners, primers, and medicaments used for dental treatment), bonding mechanism, and polymerization characteristics of MMA/TBB resin were also discussed. This review further reveals the unique adhesion features between MMA/TBB resin and dentin: in addition to monomer diffusion into the demineralized dentin surface, graft polymerization of MMA onto dentin collagen and interfacial initiation of polymerization at the resin-dentin interface provide the key bonding mechanisms.

  2. [Effect of an arginine-containing polishing paste on Streptococcus mutans adhesion to exposed dentin surfaces].

    Science.gov (United States)

    Liu, Yinchen; Fu, Dongiie; Huang, Cui; Pei, Dandan; Sun, Hualing

    2013-10-01

    To evaluate the effect of an arginine-containing antihypersensitivity polishing paste on Streptococcus mutans (S. mutans) adhesion to treated dentin. Dentin discs were treated with acid to expose dentin tubules, and then polished with either pumice or a polishing paste containing arginine. The surface roughness of the treated dentin was measured. The effects of dentin treatment on S. mutans adhesion and glucosyltransferase (GTFs) gene expression were also evaluated. The surface roughness decreased after polishing with both pumice and arginine-containing polishing paste. Moreover, the polishing paste affected gtfB and gtfC expressions. The arginine-containing polishing paste affects S. mutans adhesion, as well as gtfB and gtfC expressions. The polishing paste may be used to prevent caries in exposed dentin areas.

  3. Effect of intracoronal bleaching agents on ultrastructure and mineral content of dentin.

    Science.gov (United States)

    Maleknejad, Fatemeh; Ameri, Hamideh; Kianfar, Iman

    2012-04-01

    The purpose of this in vitro study was to evaluate the ultrastructural changes of dentin induced after exposure to different intracoronal tooth bleaching agents. Dental discs of 1 mm thickness were prepared from coronal dentin of sixty-four human maxillary premolars. Experimental specimens were divided into four subgroups: 45% carbamide peroxide, 35% hydrogen peroxide, sodium perborate + 30% hydrogen peroxide, sodium perborate + water. The specimens were then evaluated under scanning electron microscope to determine diameter of dentinal tubules and chemical analysis. There was significant difference between dentinal tubule diameter of all test and control groups with the exception of sodium perborate + water. Chemical analysis revealed that there was no significant difference between experimental subgroups regarding calcium and sulfur wt%. All bleaching agents increased dentinal tubule diameter and promote alterations in mineral content of dentin with the exception of Sodium perborate mixed with water.

  4. Three-dimensional finite element analysis of the stress distribution in the endodontically treated maxillary central incisor by glass fiber post and dentin post

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    Sarfaraz Memon

    2016-01-01

    Conclusion: The FEA results showed that the stress in the cervical area of the dentin was more for fiber post when compared to dentin post, and maximum displacement values were less for dentin post in comparison to fiber post.

  5. Suspensão de cirurgia de catarata e suas causas Reasons for cataract surgery cancelation

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    Rodrigo Pessoa Cavalcanti Lira

    2001-10-01

    Full Text Available Com o objetivo de verificar as causas de suspensão de cirurgia de catarata e sugerir medidas para melhorar a eficiência do serviço prestado à população, foi realizado um estudo transversal no serviço de oftalmologia de um hospital universitário do Estado de São Paulo. A amostra foi composta por 200 indivíduos. A média de idade foi de 68± 11,4 anos. As causas de suspensão de cirurgia foram: condição clínica desfavorável (23,1%; horário cirúrgico insuficiente (35,9%; e não comparecimento do paciente (41%. Os fatores causadores foram, majoritariamente, as razões sociais e o funcionamento do hospital.To study the reasons for canceling cataract surgeries, and to suggest actions to improve the efficiency of patient care. A cross-sectional study was carried out in a university hospital's ophthalmology clinic of the state of São Paulo, Brazil. Two hundred subjects were randomly selected. The mean age was 68± 11.4 years old. The reasons for canceling surgery were: unpropitious clinical condition (23.1%; tight schedule (35.9%; and patient non-attendance (41%. Most of the reasons related to social issues and the hospital's administrative aspects.

  6. Mortalidade infantil por causas evitáveis em uma cidade do Nordeste do Brasil

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    Suelayne Gonçalves do Nascimento

    2014-04-01

    Full Text Available Estudo de corte transversal que objetivou descrever a ocorrência da mortalidade infantil em Recife (PE entre 2000 e 2009, segundo causas evitáveis. A população foi composta pelos óbitos infantis de mães residentes na cidade do Recife e a classificação de evitabilidade adotou a Lista de causas de mortes evitáveis por intervenções do Sistema Único de Saúde. Para análise dos dados utilizou-se estatística descritiva. Foi observado decréscimo no coeficiente de mortalidade infantil de 20,4 para 12,1 por 1.000 nascidos vivos. Do total de 3.743 óbitos registrados, 2.861 (76,4% foram classificados como evitáveis. Destacaram-se os óbitos reduzíveis por adequada atenção à mulher na gestação. A abordagem da evitabilidade auxilia nas discussões relacionadas à organização, qualidade e acesso aos serviços de saúde, bem como na identificação dos óbitos que poderiam ter sido prevenidos ou evitados por uma adequada atenção à saúde materno-infantil.

  7. Adhesive strength between composite resin and dentin substract

    OpenAIRE

    BIANCHI, Joel; Rodrigues Filho,Leonardo Eloy; SANTOS, José Fortunato Ferreira

    1999-01-01

    As pesquisas relacionadas com adesão à dentina, em virtude da ampla aplicabilidade, são de grande interesse para a Odontologia. O objetivo deste estudo foi avaliar, através de ensaios de tração, a resistência adesiva ao substrato dentinário, em função de dois sistemas adesivos (3M e Kerr), dois níveis de rugosidade do substrato dentinário (lixas 220 e 600), duas áreas de colagem (3,14 mm2 - 12,56 mm2), e duas condições de armazenagem (inicial e final). A análise dos resultados evidenciou que:...

  8. Antimicrobial effect of ozonated water on bacteria invading dentinal tubules.

    Science.gov (United States)

    Nagayoshi, Masato; Kitamura, Chiaki; Fukuizumi, Takaki; Nishihara, Tatsuji; Terashita, Masamichi

    2004-11-01

    Ozone is known to act as a strong antimicrobial agent against bacteria, fungi, and viruses. In the present study, we examined the effect of ozonated water against Enterococcus faecalis and Streptcoccus mutans infections in vitro in bovine dentin. After irrigation with ozonated water, the viability of E. faecalis and S. mutans invading dentinal tubules significantly decreased. Notably, when the specimen was irrigated with sonication, ozonated water had nearly the same antimicrobial activity as 2.5% sodium hypochlorite (NaOCl). We also compared the cytotoxicity against L-929 mouse fibroblasts between ozonated water and NaOCl. The metabolic activity of fibroblasts was high when the cells were treated with ozonated water, whereas that of fibroblasts significantly decreased when the cells were treated with 2.5% NaOCl. These results suggest that ozonated water application may be useful for endodontic therapy.

  9. Clinical and histologic observations of opalescent dentin associated with enamel defects.

    Science.gov (United States)

    Suzuki, S; Nakata, M; Eto, K

    1977-11-01

    The rare variant of opalescent dentin associated with enamel defect was found in a 1 1/2-year-old boy. The pulp chambers and root canals of the affected deciduous teeth were very large, with no sign of obliteration. The enamel layer of those teeth was markedly reduced in thickness, and the enamel prisms were not recognized even by scanning electron microscopy. The mantle dentin was abnormal, as were other portions of dentin.

  10. Ammonium hexafluorosilicate elicits calcium phosphate precipitation and shows continuous dentin tubule occlusion.

    Science.gov (United States)

    Suge, Toshiyuki; Kawasaki, Akiko; Ishikawa, Kunio; Matsuo, Takashi; Ebisu, Shigeyuki

    2008-02-01

    Diamine silver fluoride [AgF: (NH(3))(2)AgF] has been used clinically in Japan, as it reduces dental caries and dentin hypersensitivity. However, AgF stains the teeth black due to silver precipitation. To overcome this drawback, the authors prepared ammonium hexafluorosilicate [SiF: (NH(4))(2)SiF(6)], which does not stain the teeth, and SiF occluded open dentin tubules completely with silica-calcium phosphate precipitate. The aim of this study was to evaluate the duration of dentin tubule occlusion after SiF treatment in a simulated oral environment. To simulate dentin tubules subject to dentin hypersensitivity, dentin disks were treated with EDTA for 2 min. The disks were treated with 0.476 mol/L SiF for 3 min, and then the disks were immersed in synthetic saliva, which was regularly replenished to maintain its ionic concentration, for up to 7 days. The occluding ability of the dentin tubules was evaluated using scanning electron microscopy (SEM), and the hydraulic conductance was measured following Pashley's method at regular intervals. SEM photographs demonstrated that dentin tubules were occluded homogeneously and completely with the precipitate at 7 days after treatment with SiF. In addition, newly formed calcium phosphate precipitate was present at the dentin surface. The dentin permeability showed a consistently low value throughout the experimental period. The values immediately after SiF treatment and 7 days after immersion were 11.9+/-3.7% and 7.9+/-2.9%, respectively. Ammonium hexafluorosilicate is useful for the treatment of dentin hypersensitivity, since ammonium hexafluorosilicate induced calcium phosphate precipitation from the saliva; therefore, it has a continuous effect on dentin tubules occlusion under a simulated oral environment.

  11. Comparative study of tubular diameter and quantity for human and bovine dentin at different depths

    OpenAIRE

    Lopes,Murilo Baena; Sinhoreti,Mário A. C.; Gonini Júnior,Alcides; Consani,Simonides; Mccabe,John F.

    2009-01-01

    This study compared the tubular dimensions and distribution of human and bovine dentin. Ten human molars and 10 bovine incisors were ground with a high-speed handpiece to obtain 3 sections at different dentin depths (superficial, middle and deep). The specimens were sputter-coated with gold to be examined under scanning electron microscopy (SEM). Three SEM micrographs were recorded randomly for each dentin depth. The number of tubules was counted and the diameter of 5 tubules selected at rand...

  12. Variation of dentin dysplasia type I: report of atypical findings in the permanent dentition

    OpenAIRE

    Rocha,Cristiane Tomaz; Nelson-Filho,Paulo; SILVA,Léa Assed Bezerra da; Assed, Sada; QUEIROZ,Alexandra Mussolino de

    2011-01-01

    Dentin dysplasia is a rare defect of dentin development with an autosomal dominant pattern of inheritance, which is generally divided into 2 main classes based on the clinical and radiographic appearance of the affected dental tissues: type I, which affects the root portion and type II, which affects the coronal portion of the tooth. This paper reports the case of a child aged 10 years and 8 months with both classic and atypical features of dentin dysplasia type I in the permanent dentition. ...

  13. Evaluation of Caries Dentin Using Light-Induced Fluorescence: A Case Report

    OpenAIRE

    Erol, Sebnem; Kamak, Hanife; Erten, Hülya

    2014-01-01

    Minimal invasive therapy has been becoming more important day by day in dentistry. In minimally invasive dentistry, only the infected dentin is removed and the affected dentin is left behind while preparing to repair a cavity. Healthy enamel and dentin have particular fluorescence properties, compared to demineralized dental tissues, which absorb less light and thereby have a lower level of fluorescence properties. It helps clinicians detect caries and apply the most appropriate treatment str...

  14. Selective removal of carious lesion with Er:YAG laser followed by dentin biomodification with chitosan.

    Science.gov (United States)

    Curylofo-Zotti, Fabiana A; Tanta, Gabriela Solano; Zucoloto, Miriane Lucindo; Souza-Gabriel, Aline E; Corona, Silmara A M

    2017-09-01

    The aim of this study was to evaluate the effect of Er:YAG laser for selective removal of carious lesion, followed by biomodification with chitosan gel where the subsurface microhardness, chemical composition, and morphological changes of the residual caries-affected dentin were examined. Artificial dentinal lesions were created by pH-cycling method (14 days) in 104 bovine specimens (5 × 5 mm). Specimens were randomly divided according to the carious removal method: bur (low-speed handpiece) or Er:YAG laser (250 mJ/4 Hz). Specimens were treated with 35% phosphoric acid and were subdivided into two groups according to dentin biomodification: without chitosan (control) and 2.5% chitosan. Forty specimens were restored with an adhesive system and composite resin. Subsurface microhardness tests were performed in sound dentin, caries-affected dentin, residual caries-affected dentin, and after the restoration. The other 64 specimens were subjected to SEM-EDS atomic analysis. Data were statistically analyzed (p laser excavation, the microhardness value of residual caries-affected dentin was higher (p laser (p caries-affected dentin (p > 0.05). SEM analysis showed morphological changes on residual caries-affected dentin (p > 0.05). The selective removal of carious dentin with Er:YAG laser increased microhardness of residual caries-affected dentin, changing its surface morphology and chemical composition. The biomodification with chitosan did not influence the structural and chemical composition of residual caries-affected dentin.

  15. The deposition of AgCl into tubules of the human tooth dentine

    Science.gov (United States)

    Levstik, A.; Leskovec, J.; Filipic, C.; Kutnjak, Z.; Zeks, B.; Kordas, M.

    2001-03-01

    The deposition of AgCl in the human tooth dentine was studied as a function of the time and dc electrical field using a scanning electron microscope and by measurements of the frequency-dependent complex dielectric constant. Dielectric properties of the tooth dentine can be well described by the model which was recently developed for the dielectric response of hydrating porous cement paste. The fractal dimension of the tooth dentine was determined by the electron microscopy and dielectric spectroscopy techniques.

  16. Vitality of Enterococcus faecalis inside dentinal tubules after five root canal disinfection methods

    OpenAIRE

    Niranjan Ashok Vatkar; Vivek Hegde; Sucheta Sathe

    2016-01-01

    Aim: To compare the vitality of Enterococcus faecalis within dentinal tubules after subjected to five root canal disinfection methods. Materials and Methods: Dentin blocks (n = 60) were colonized with E. faecalis. After 4 weeks of incubation, the dentin blocks were divided into one control and five test groups (n = 10 each). The root canals of test groups were subjected to one of the disinfection methods, namely, normal saline (NS), sodium hypochlorite (NaOCl), chlorhexidine digluconate (C...

  17. Determining Fetal Manganese Exposure from Mantle Dentine of Deciduous Teeth

    OpenAIRE

    Arora, Manish; Bradman, Asa; Austin, Christine; Vedar, Michelle; Holland, Nina; Eskenazi, Brenda; Smith, Donald R.

    2012-01-01

    Studies addressing health effects of manganese (Mn) excess or deficiency during prenatal development are hampered by a lack of biomarkers that can reconstruct fetal exposure. We propose a method using the neonatal line, a histological feature in deciduous teeth, to identify regions of mantle dentine formed at different prenatal periods. Micro-measurements of Mn in these regions may be used to reconstruct exposure at specific times in fetal development. To test our hypothesis, we recruited pre...

  18. Odontoblast-targeted Bcl-2 Overexpression Impairs Dentin Formation

    Science.gov (United States)

    Zhang, Wenjian; Ju, Jun; Gronowicz, Gloria.

    2010-01-01

    Apoptosis has been described extensively in tooth development, which is under tight control of multiple apoptosis regulators, including anti-apoptotic protein Bcl-2. However, it is totally unclear how Bcl-2 is related to odontogenesis, especially dentinogenesis. Using a transgenic mouse Col2.3Bcl-2 in which human Bcl-2 was overexpressed in odontoblasts, the effect of Bcl-2 on dentinogenesis was investigated. Overexpression of Bcl-2 was detected by immunohistochemistry and Western blot. Odontoblast apoptosis was evaluated by TUNEL and Western blot detection of cleaved caspase-3. Odontoblast differentiation was assessed by real-time PCR detection of dentin matrix expression. Dentin mineralization was evaluated by micro-CT in vivo, and alizarin red S staining and calcium content analysis in vitro. Bcl-2 was found to be overexpressed in odontoblasts and prevent their apoptosis. Odontoblast differentiation and mineralization was inhibited by Bcl-2, as evidenced by lower expressions of DMP-1, OC, and DSPP, and decreased odontoblast mineralization in vitro, as well as decreased dentin thickness and mineral density in vivo when compared to the wild type animals. Inhibition of odontoblast differentiation by Bcl-2 occurs, at least partially, via a suppression of MEK-ERK1/2 signaling pathway. In conclusion, Bcl-2 overexpression prevents odontoblast apoptosis and impairs dentin formation, partially via an inhibition of odontoblast differentiation. This study revealed some novel functions of Bcl-2 in dentinogenesis in addition to its anti-apoptotic effect, which shed some light on the genetic complexity of tooth development. PMID:20518070

  19. Effect of two desensitizing agents on dentin permeability in vitro

    Directory of Open Access Journals (Sweden)

    Hiroshi ISHIHATA

    Full Text Available Abstract Objective The aim of this in vitro study was to investigate the effect of two desensitizing agents and water on hydraulic conductance in human dentin. Material and Methods GLUMA Desensitizer PowerGel (GLU contains glutaraldehyde (GA and 2-hydroxyethyl methacrylate (HEMA, and Teethmate Desensitizer (TD is a powder comprising tetracalcium phosphate (TTCP and dicalcium phosphate anhydrous (DCPA that is mixed with water. Deionized water was used as a negative control (CTR. Thirty discs with a thickness of 1.2 mm were cut from the coronal dentin of the third molars and cleaned with 0.5 M EDTA (pH 7.4. After being mounted in a split-chamber device, the discs were pressurized with water at 1 kPa and 3 kPa in order to measure flow rates with a highly sensitive micro-flow sensor and to calculate hydraulic conductance as a baseline value (BL. Following the application of GLU, TD, and CTR (n=10, hydraulic conductance was remeasured with intermittent storage in water after 15 min, 1 d, 1 w, and 1 m. Reduction in permeability (PR% was calculated from hydraulic conductance. Data were statistically analyzed using nonparametric methods (α<0.05. Representative discs were inspected by SEM. Results PR% for GLU and TD were 30-50% 15 min and 1 m after their application. Post hoc tests indicated that PR% of CTR was significantly greater than those of GLU and TD at all time points tested. The PR% of GLU and TD were not significantly different. SEM examinations showed noncollapsed collagen meshes at the tubular entrances after GLU, and crystalline precipitates occluding the tubular orifices after TD, whereas CTR specimens showed typical patterns of etched dentin. Conclusions The present study on hydraulic conductance in dentin discs treated with two chemically different desensitizing agents and water as a control demonstrated that both products may be characterized as effective.

  20. Dentin-smear remains at self-etch adhesive interface.

    Science.gov (United States)

    Mine, Atsushi; De Munck, Jan; Cardoso, Marcio Vivan; Van Landuyt, Kirsten L; Poitevin, André; Van Ende, Annelies; Matsumoto, Mariko; Yoshida, Yasuhiro; Kuboki, Takuo; Yatani, Hirofumi; Van Meerbeek, Bart

    2014-10-01

    The bonding potential of 'mild' self-etch adhesives may be compromised due to smear interference, as they may not dissolve/penetrate the smear layer effectively due to their relatively low acidity. We observed that the thickness of the dentin smear layer differed depending on the surface-preparation methodology used. The interaction of an (ultra-)mild self-etch adhesive (Clearfil S3 Bond, Kuraray Noritake) with human dentin, prepared either using a medium-grit diamond bur ('thick', clinically relevant smear layer) or 600-grit SiC-paper ('thin' smear layer), or just fractured (smear-free), was evaluated using high-resolution transmission electron microscopy (TEM). Non-demineralized/demineralized 30-100nm interfacial cross-sections were prepared following common TEM-specimen processing and diamond-knife ultra-microtomy. The adhesive did not dissolve the bur-cut, nor the SiC-ground smear layer, but impregnated it. Within this 'resin-smear complex', hydroxyapatite was abundantly present. At fractured dentin, this complex was not present, while the actual layer of interaction of the adhesive was limited to about 100nm. Non-demineralized 'ultra-thin' (30-50nm) sections confirmed the interfacial ultra-structure to differ for the three surface-preparation methods. An electron dense band was consistently disclosed at the adhesive interface, most likely representing the documented chemical interaction of the functional monomer 10-MDP with Ca. The dentin surface-preparation method significantly affects the nature of the smear layer and the interaction with the ultra-mild self-etch adhesive. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  1. Laser treatment of enamel and dentine by different Er lasers

    Science.gov (United States)

    Altshuler, Gregory B.; Belikov, Andrei V.; Erofeev, Andrew V.

    1994-09-01

    The results of primary comparative investigation of possible application of lasers based on four different Er-doped crystals (YAG, YLF, YSGG, YAP) are presented. The influence of laser wavelength and temporal structure of laser radiation on efficiency of hard tooth tissues treatment is considered. The experimental data on damage thresholds and efficiency of enamel and dentine removal under influence of submillisecond pulses of all four types of lasers are obtained.

  2. Effects of fluoridated milk on root dentin remineralization.

    Directory of Open Access Journals (Sweden)

    Wolfgang H Arnold

    Full Text Available The prevalence of root caries is increasing with greater life expectancy and number of retained teeth. Therefore, new preventive strategies should be developed to reduce the prevalence of root caries. The aim of this study was to investigate the effects of fluoridated milk on the remineralization of root dentin and to compare these effects to those of sodium fluoride (NaF application without milk.Thirty extracted human molars were divided into 6 groups, and the root cementum was removed from each tooth. The dentin surface was demineralized and then incubated with one of the following six solutions: Sodium chloride NaCl, artificial saliva, milk, milk+2.5 ppm fluoride, milk+10 ppm fluoride and artificial saliva+10 ppm fluoride. Serial sections were cut through the lesions and investigated with polarized light microscopy and quantitative morphometry, scanning electron microscopy (SEM and energy-dispersive X-ray spectroscopy (EDS. The data were statistically evaluated using a one-way ANOVA for multiple comparisons.The depth of the lesion decreased with increasing fluoride concentration and was the smallest after incubation with artificial saliva+10 ppm fluoride. SEM analysis revealed a clearly demarcated superficial remineralized zone after incubation with milk+2.5 ppm fluoride, milk+10 ppm fluoride and artificial saliva+10 ppm fluoride. Ca content in this zone increased with increasing fluoride content and was highest after artificial saliva+10 ppm fluoride incubation. In the artificial saliva+10 ppm fluoride group, an additional crystalline layer was present on top of the lesion that contained elevated levels of F and Ca.Incubation of root dentin with fluoridated milk showed a clear effect on root dentin remineralization, and incubation with NaF dissolved in artificial saliva demonstrated a stronger effect.

  3. Sodium hypochlorite solution penetration into human dentine: a histochemical evaluation.

    Science.gov (United States)

    Giardino, L; Cavani, F; Generali, L

    2017-05-01

    The aim of this study was to evaluate ex vivo the penetration depth of sodium hypochlorite solutions, with and without surfactants, into human dentine using a histochemical stain and the bleaching ability of NaOCl. Extracted maxillary central incisors were decoronated and their root canals were shaped to a size 30, .07 taper. Dentinal tubules were stained with 10% copper sulphate solution followed by a 1% rubeanic acid alcohol solution under vacuum. Specimens were irrigated with 5 mL of Niclor 5 (5.25% NaOCl solution) or 5 mL of Hypoclean (5.25% NaOCl solution + surfactants) according to the corresponding treatment group, for 2 min. A transverse section was obtained in the middle portion of the apical, middle and coronal thirds of each tooth. Under microscopic examination, irrigant penetration was evaluated by measuring the following: the bleached circumference of the root canal with respect to the stained circumference; bleached areas, mean and maximum penetration depth. For statistical analysis, Pearson's chi-squared test and one-way anova were used. Only 30% of dentine tubules in the apical portions were stained; therefore, these were excluded from further comparisons. In the middle and coronal thirds, the average bleached circumference of the root canal was 80-99% of the stained circumference and the bleached area was 73757-135107 μm(2) . The average penetration depth ranged from 39 to 62 μm and maximum penetration from 74 to 131 μm. For all reported results, no differences within and between groups were observed (P = 1). No differences in penetration of irrigants with and without surfactants into dentinal tubules were observed in the middle and coronal thirds of incisor teeth. © 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  4. Evaluation of caries-affected dentin with optical coherence tomography

    Directory of Open Access Journals (Sweden)

    Cynthia Soares de Azevedo

    2011-10-01

    Full Text Available The purpose of this study was to evaluate the degree of demineralization of artificially induced caries-affected human dentin by an in vitro microbiological method. The occlusal surfaces of 6 human molar teeth were abraded until a flat surface was obtained, and the enamel was removed to expose the occlusal dentin surface. These teeth were sectioned in 12 halves in the vestibular-lingual direction and divided into 3 groups according to the period length of the microbiological essay (n = 4: G1, 7 days; G2, 14 days; and G3, 21 days. The surfaces of all specimens were protected by an acid-resistant nail varnish, except for a window where the caries lesion was induced by a Streptoccocus mutans biofilm in a batch-culture model supplemented with 5% sucrose. The specimens were then analyzed by optical coherence tomography (OCT with a super-luminescent light diode (Λ = 930 nm with 6.0-µm lateral and longitudinal resolution (in the air. Qualitative and quantitative results (images and average dentin demineralization, respectively were obtained. The mean demineralization depths were (µm 235 ± 31.4, 279 ± 14, and 271 ± 8.3 in groups 1, 2, and 3, respectively. In addition, no significant change was observed in the lesion mean depth from 7 days of cariogenic challenge on. In conclusion, OCT was shown to be an efficient and non-invasive method to detect the depths of lesions caused by demineralization. Further, a seven-day demineralization time was considered sufficient for caries-affected dentin to be obtained.

  5. Photodynamic antimicrobial therapy of curcumin in biofilms and carious dentine.

    Science.gov (United States)

    Araújo, N C; Fontana, C R; Bagnato, V S; Gerbi, M E M

    2014-03-01

    Photodynamic therapy (PDT) is a technique that involves the activation of photosensitizers by light in the presence of oxygen, resulting in the production of reactive radicals that are capable of inducing cell death. The present study evaluated the susceptibility of Streptococcus mutans and Lactobacillus acidophilus to PDT grown as multi-species in the biofilm phase versus in dentine carious lesions. A brain-heart infusion culture medium supplemented with 1% glucose, 2% sucrose, and 1% young primary culture of L. acidophilus 10(8) CFU/mL and S. mutans 10(8) CFU/mL was used to develop multi-species biofilms and to induce caries on human dentine slabs. Five different concentrations of curcumin (0.75, 1.5, 3.0, 4.0, and 5.0 g/L) were used associated with 5.7 J/cm(2) light emission diode. Four different groups were analyzed L-D- (control group), L-D+ (drug group), L+D- (light group), and L+D+ (PDT group). ANOVA/Tukey's tests were conducted to compare groups. A significant reduction (p <0.05) in cell viability was observed in the biofilm phase following photosensitization with all curcumin concentrations tested. To achieve significant bacterial reduction (p <0.05) in carious dentine, it was necessary to utilize 5.0 g/L of curcumin in association with blue light. No significant reduction was found for L-D+, supporting the absence of the drug's dark toxicity. S. mutans and L. acidophilus were susceptible to curcumin in the presence of blue light. However, due to light penetration and drug diffusion difficulties, these microorganisms within dentine carious lesions were less affected than they were in the biofilm phase.

  6. Effect of bleaching agents on bonding to pulp chamber dentine.

    Science.gov (United States)

    Timpawat, S; Nipattamanon, C; Kijsamanmith, K; Messer, H H

    2005-04-01

    To determine the effect of intracoronal bleaching agents on adhesion of bonding agents to pulp chamber dentine. Forty extracted human maxillary anterior teeth were randomly divided into four groups of 10 teeth each. Bleaching agents were sealed in pulp chambers for 7 days, as in clinical use. Group 1 (control): distilled water, group 2: 35% hydrogen peroxide, group 3: sodium perborate mixed with water, and group 4: sodium perborate mixed with 35% hydrogen peroxide. Teeth were stored in saline at 37 degrees C for 7 days. After the bleaching agent was removed, teeth were leached in water for a further 7 days prior to bonding. The crown was cut vertically from mesial to distal and the labial pulp chamber dentine was prepared for bonding with Clearfil SE-Bond and filled with resin composite (Clearfil AP-X). The bonded specimens were kept moist at 37 degrees C for 24 h. Microtensile bond strengths were determined using a universal testing machine. Additional teeth were prepared using the same bleaching procedures to investigate the scanning electron microscopic appearance of the dentine surface. Mean values (+/-SD) of microtensile bond strength for the experimental groups were: group 1: 5.29 +/- 2.21 MPa, group 2: 5.99 +/- 1.51 MPa, group 3: 9.17 +/- 1.65 MPa and group 4: 3.99 +/- 1.31 MPa. Dentine treated with sodium perborate in water (group 3) had significantly higher mean bond strength when compared with the other three groups (P sodium perborate plus hydrogen peroxide (group 4). In terms of subsequent bond strength during restoration, sodium perborate mixed with distilled water appears to be the best intracoronal bleaching agent.

  7. Comparative evaluation of self-etching primers with fourth and fifth generation dentin-bonding systems on carious and normal dentin substrates: An in vitro shear bond strength analysis.

    Science.gov (United States)

    Giriyappa, Ramesh H; Chandra, B Suresh

    2008-10-01

    The aim of this study was to test the hypothesis that bonding to caries-affected dentin would yield strengths that are lower than bond strengths achievable when bonded to normal dentin. Dentin-bonding systems used in this study were fourth and fifth generation as well as self-etching primers. Forty-eight freshly extracted mandibular and maxillary molars were selected of which 24 were caries-affected teeth and the remaining were noncarious teeth. Random sampling was done with eight teeth in each group based on the bonding system used. In caries-affected teeth, the soft, stainable, caries-infected dentin was excavated using a caries detector dye whereas the hard, caries-affected, nonstainable dentin was retained. All the teeth were subsequently mounted in a suitable acrylic mould. Prepared teeth were restored with a single composite resin, using three different dentin bonding systems. These prepared specimens were transferred to a Hounsfield tensometer to measure the shear bond strength. The results obtained were analyzed using Anova, Student's unpaired t-test, and Student Neuman Keulis test. The results showed that the self-etching primer required the highest mean shear load compared to the fifth and fourth generation dentin-bonding systems in both normal dentin and caries-affected dentin. Bond strength to dentin depends on whether the dentinal tubule is open or occluded. Within the limitations of this study, it was observed that bond strength to caries-affected dentin was low compared to normal dentin.

  8. Aging and Fracture of Human Cortical Bone and Tooth Dentin

    Energy Technology Data Exchange (ETDEWEB)

    Ager, Joel; Koester, Kurt J.; Ager III, Joel W.; Ritchie, Robert O.

    2008-05-07

    Mineralized tissues, such as bone and tooth dentin, serve as structural materials in the human body and, as such, have evolved to resist fracture. In assessing their quantitative fracture resistance or toughness, it is important to distinguish between intrinsic toughening mechanisms which function ahead of the crack tip, such as plasticity in metals, and extrinsic mechanisms which function primarily behind the tip, such as crack bridging in ceramics. Bone and dentin derive their resistance to fracture principally from extrinsic toughening mechanisms which have their origins in the hierarchical microstructure of these mineralized tissues. Experimentally, quantification of these toughening mechanisms requires a crack-growth resistance approach, which can be achieved by measuring the crack-driving force, e.g., the stress intensity, as a function of crack extension ("R-curve approach"). Here this methodology is used to study of the effect of aging on the fracture properties of human cortical bone and human dentin in order to discern the microstructural origins of toughness in these materials.

  9. [Dentin hypersensitivity and its significance in dental practice].

    Science.gov (United States)

    Bánóczy, Jolán

    2002-12-01

    Dentin hypersensitivity is not a new disease, more than a hundred years ago Gysi, later Brännström and many others were dealing with the problems of its symptoms, pathomechanism, differential diagnosis and therapy. The growing interest today maybe attributed to improving oral health, and to the presence of more teeth in older age, as a consequence of decreasing caries prevalence. The exposure of dentine surfaces due to gingival recession, erosion and abrasion may cause serious complaints, occurs in about 40% of the adult population, however, few of them turn to the dentist. Therefore, practising dentists should be aware of the possibilities of treatment, managing strategies and prevention. New aspects are the appropriate timing of toothbrushing after consumption of acidogenic, erosive foods and beverages, non-invasive (desensitizing, potassium-nitrate/fluoride containing toothpastes), and invasive (reconstruction with fillings, coverage of the exposed roots) treatment options. Continuous care of patients suffering in dentine hypersensitivity--in order to prevent more serious consequences (irritation of the pulp)--is advisable.

  10. Study of three types of desensitizers in dentin bonding strength.

    Science.gov (United States)

    Cheng, L; Wang, S; Che, Y H; Qian, M

    One hundred and twenty human molars without decay (premolars and complete third molars) freshly extracted for orthodontic purposes were used in the study to explore the impact of application of three kinds of desensitizers on self-etching/all-etching bond strength of dentin. The roots were ground along the cementoenamel junction (CEJ), the residual crowns were divided into two parts along mesial and distal direction, and the enamel layer was removed. The dentin was ground into standard pieces of 3x3x3 mm and then polished using alumina waterproof abrasive paper. Two hundred and forty specimens were divided into two groups according to self-etching bond (OptiBond, iBond, XenoIV) and all-etching bond (OptiBond, iBond, Probond). Each of the two groups were subdivided into three groups with different brands, and then further subdivided into three experimental groups and a control group (10 samples in each final group). The surface of dentin coated with desensitizer was examined using scanning electron microscope. Results showed that only the shear strength of iBond + Ddes + Z100 resin group was lower compared to the control group (P 0.05). The shear strength of Optibond + Gluma, Optibond + Ddes, iBond + Ddes + Z100 resin group in all-etching bond group and the experimental groups in Probond group was lower than in the control group (P 0.05).

  11. Testing mode and surface treatment effects on dentin bonding.

    Science.gov (United States)

    Drummond, J L; Sakaguchi, R L; Racean, D C; Wozny, J; Steinberg, A D

    1996-12-01

    The goal of this project was to evaluate the effect of the following variables on shear dentin-bonding test results: mode of testing (cyclic fatigue versus static loading), surface treatments (32% phosphoric acid, 10% phosphoric acid, and no treatment [unetched]), and type of shear test (traditional planar versus push-out). All teeth were stored in distilled water and tested in a shear mode at a loading rate of 2 mm/ min. The specimens were loaded in static or cycled for 1000 cycles using a staircase approach or until fracture, whichever occurred first. On samples with etched dentin surfaces, the push-out test did not demonstrate a significant difference in measured bond strength when compared with results from the planar test, although sample preparation was more labor-intensive. The bond strength resulting from cyclic fatigue of the etched specimens was approximately 51% of the static loading value. Ten percent phosphoric acid was as effective as 32% phosphoric acid for dentin bonding. Finite-element analysis indicated that the traditional planar shear test produces flexure of the specimen and high tensile stress magnitudes within the resin bonding layer. The push-out test produces elevated compressive stresses localized in the composite along the circumference of the punch. Shear stresses in the resin bonding layer are similar for both testing methods at the same loading element contact force.

  12. Holmium:YAG laser in dentistry: photoconditioning of dentinal surfaces

    Science.gov (United States)

    Holt, Raleigh A.; Nordquist, Robert E.

    1994-09-01

    This in vitro study was undertaken to determine energy levels necessary to produce tubule closure and surface smoothing on dentinal surfaces of human teeth and their resultant temperature increases within the pulpal canals with the Holmium:YAG laser. An optimal working spot size and even absorption pattern were produced by defocusing the laser beam and evaluated by images produced on light exposed and developed photographic paper. The surface effects on dentin were examined by scanning electron microscopy. A thermocouple was positioned in the canals of fresh dissected dog jaws and attached to a recorder which produced a graph of the temperature changes. The in vitro research model for intrapulpal temperatures changes was verified by comparing premortem and postmortem temperature readings. The same protocol was used to evaluate temperature changes in fresh human extracted teeth. In vivo histological studies were conducted to evaluate the effects of HO:YAG laser energy on pulpal tissues. The results of these studies indicate the HO:YAG laser at a wavelength of 2.12 microns can be safely and effectively used for photoconditioning of the dentinal surfaces of teeth in clinical conditions.

  13. Dentin rehardening after indirect pulp treatment in primary teeth.

    Science.gov (United States)

    Franzon, R; Gomes, M; Pitoni, C M; Bergmann, C P; Araujo, F B

    2009-01-01

    The purpose of this study was to investigate dentin rehardening in the remaining carious dentin after indirect pulp treatment (IPT) using microhardness analysis after 37 to 71 months. Eighteen teeth submitted to IPT and capped with calcium hydroxide (CH) or gutta-percha (GP) were evaluated (treated group). Ten sound molars and 10 molars with deep acute carious lesions were selected to serve as positive and negative control groups, respectively. In the treated group, restorations and pulp-capping materials were removed. In the positive control group, 3- to 4-mm deep cavities were prepared. In the negative control group, the carious tissue was removed. Microhardness analysis was performed at 10-, 35-, 60-, 85-, and 110-microm depths. Data were analyzed using 1-way analysis of variance (P<.05). Microhardness values for sound, carious, and treated groups at 10-, 35-, 60-, 85-, and 110-microm depths showed a statistically significant difference (Pdentin depths investigated, suggesting mineral gain after treatment.

  14. Effect of a novel bioactive glass-ceramic on dentinal tubule occlusion: an in vitro study.

    Science.gov (United States)

    Zhong, Y; Liu, J; Li, X; Yin, W; He, T; Hu, D; Liao, Y; Yao, X; Wang, Y

    2015-03-01

    This in vitro study aimed to assess the ability and efficacy of HX-BGC, a novel bioactive glass-ceramic (SiO2-P2 O5-CaO-Na2 O-SrO), to reduce dentine tubule permeability. Dentine discs from human third molars were etched and randomly allocated into five groups: Group 1--distilled water; Group 2--Sensodyne Repair toothpaste (containing NovaMin®); Group 3--HX-BGC toothpaste (containing 7.5% HX-BGC); Group 4--control toothpaste (without HX-BGC); and Group 5--HX-BGC powder. Specimens were treated daily by brushing with an electric toothbrush for 20 seconds. Between daily treatments (7 days total), specimens were immersed in artificial saliva for 24 hours. Dentine permeability was measured at baseline, after the first treatment, after the first 24-hour immersion in artificial saliva and at the end of day 7. Dentine morphology and surface deposits were observed by scanning electron microscopy after one day and 7 days of treatment, respectively. Sensodyne Repair and bioactive glass-ceramic toothpaste significantly and immediately lowered dentine permeability. The HX-BGC powder group showed the highest reduction in dentine permeability after 7 days of treatment. The novel bioactive glass-ceramic material HX-BGC is effective in reducing dentine permeability by occluding open dentine tubules, indicating that HX-BGC may be a potential treatment for dentine hypersensitivity. © 2015 Australian Dental Association.

  15. Cross-linked demineralized dentin maintains its mechanical stability when challenged by bacterial collagenase.

    Science.gov (United States)

    Xu, Changqi; Wang, Yong

    2011-02-01

    The molecular structure, weight loss, and mechanical properties of demineralized dentin of noncrosslinked/crosslinked by glutaraldehyde (GA) were investigated when being challenged by bacterial collagenase solution over time in this study. Raman spectra proved that crosslinking occurred in demineralized dentin matrices after being treated with GA. Meanwhile, the weight of the cross-linked demineralized dentin matrices did not change after being challenged by bacterial collagenase solution up to 1 week. However, the weight of noncross-linked dentin collagen fell by almost 45% after degradation for 5 h, and up to 100% after 19 h. The tensile strength of demineralized dentin matrices did not show a significant change after being crosslinked, while the stiffness of demineralized dentin matrices showed more improvement than that of noncross-linked collagen. The toughness of demineralized dentin matrices decreased slightly after being crosslinked. Importantly, neither the tensile strength of GA-cross-linked demineralized dentin nor its stiffness changed over time in either control buffer or collagenase solution compared with that of noncross-linked controls. These results suggested that improving the degree of crosslinking in dentin collagen could be one method to inhibit its biodegradation and further to increase the durability of dental restorations. Copyright © 2010 Wiley Periodicals, Inc.

  16. Low-power irradiation of Er: YAG laser using broom-type probe for dentine hypersensitivity

    Science.gov (United States)

    Watanabe, Hisashi; Kataoka, Kenzo; Iwami, Hideo; Shinoki, Takeshi; Okagami, Yoshihide; Ishikawa, Isao

    2003-06-01

    This study was performed to examine the possibility of Er:YAG laser for dentine hypersensitivity treatment using a novel laser probe; broom type probe. The morphological change of dentinal tubules of bovine dentine plate after low power laser irradiation (5 or 10 mJ, 10 pps) or boiling was observed by SEM. Fifty teeth from 13 patients aged 31-54 years with complain of dentine hypersensitivity were treated by laser irradiation at 25-35 mJ, 10 pps using the broomed probe. Clinical effect of laser irradiation was verified by the examination of sensitivity rate to cold water, air blow and mechanical stimuli of explorer at before, immediately after, and 1,3,5 and 12 weeks after laser irradiation. The ratio of blockade and reduction of dentinal tubules after laser irradiation was 16-61%. The accumulation due to vaporization of water in dentinal tubules and degeneration or coagulation of organinc elements at the site of blockade and reduction were superficially described by SEM. Remarkable clinical improvement of dentine hypersensitivity by laser was admitted but relapse was also detected partially. The present study suggests low power irradiation of Er:YAG laser would be effective on dentine hypersensitivity, but a partial limitation of laser treatment for dentine hypersensitivity may be exited.

  17. Effect of Dentin Wetness on the Bond Strength of Universal Adhesives

    OpenAIRE

    An-Na Choi; Ji-Hye Lee; Sung-Ae Son; Kyoung-Hwa Jung; Yong Hoon Kwon; Jeong-Kil Park

    2017-01-01

    The effects of dentin wetness on the bond strength and adhesive interface morphology of universal adhesives have been investigated using micro-tensile bond strength (μTBS) testing and confocal laser scanning microscopy (CLSM). Seventy-two human third molars were wet ground to expose flat dentin surfaces. They were divided into three groups according to the air-drying time of the dentin surfaces: 0 (without air drying), 5, and 10 s. The dentin surfaces were then treated with three universal ad...

  18. In vivo validation of near-infrared light transillumination for interproximal dentin caries detection.

    Science.gov (United States)

    Kühnisch, Jan; Söchtig, Friederike; Pitchika, Vinay; Laubender, Rüdiger; Neuhaus, Klaus W; Lussi, Adrian; Hickel, Reinhard

    2016-05-01

    The aims of this clinical study were to investigate the diagnostic accuracy of near-infrared light transillumination (NILT) as a novel X-ray-free method for proximal dentin caries detection and to compare this method to established diagnostic methods. A total of 127 interproximal dentin caries lesions without any cavity within visible dentin in posterior teeth from 85 consecutively selected patients were included. Visual and radiographic diagnoses and laser fluorescence measurements were available. NILT images were obtained, and a dentin lesion was predicted if a demineralisation involved the enamel-dentin junction (NILT-EDJ) or a shadow in dentin was detectable (NILT-dentin). Included lesions were opened and validated (reference standard). The statistical analyses included descriptive analyses and calculations of sensitivity, specificity and Az values. The diagnostic accuracy with respect to the reference standard was 1.6% for visual inspection, 66.7% for laser fluorescence, 96.1% for digital radiography, 29.1% for NILT-dentin and 99.2% for NILT-EDJ. Bitewings (Az 0.984) and NILT-EDJ (Az 0.992) performed equally. Given the lack of true negatives in the study, the diagnostic accuracy of NILT achieved the same level as bitewings for the detection of proximal dentin caries. This study might indicate that NILT could reduce the usage of bitewings.

  19. Longevity of Self-etch Dentin Bonding Adhesives Compared to Etch-and-rinse Dentin Bonding Adhesives: A Systematic Review.

    Science.gov (United States)

    Masarwa, Nader; Mohamed, Ahmed; Abou-Rabii, Iyad; Abu Zaghlan, Rawan; Steier, Liviu

    2016-06-01

    A systematic review and meta-analysis were performed to compare longevity of Self-Etch Dentin Bonding Adhesives to Etch-and-Rinse Dentin Bonding Adhesives. The following databases were searched for PubMed, MEDLINE, Web of Science, CINAHL, the Cochrane Library complemented by a manual search of the Journal of Adhesive Dentistry. The MESH keywords used were: "etch and rinse," "total etch," "self-etch," "dentin bonding agent," "bond durability," and "bond degradation." Included were in-vitro experimental studies performed on human dental tissues of sound tooth structure origin. The examined Self-Etch Bonds were of two subtypes; Two Steps and One Step Self-Etch Bonds, while Etch-and-Rinse Bonds were of two subtypes; Two Steps and Three Steps. The included studies measured micro tensile bond strength (μTBs) to evaluate bond strength and possible longevity of both types of dental adhesives at different times. The selected studies depended on water storage as the aging technique. Statistical analysis was performed for outcome measurements compared at 24 h, 3 months, 6 months and 12 months of water storage. After 24 hours (p-value = 0.051), 3 months (p-value = 0.756), 6 months (p-value=0.267), 12 months (p-value=0.785) of water storage self-etch adhesives showed lower μTBs when compared to the etch-and-rinse adhesives, but the comparisons were statistically insignificant. In this study, longevity of Dentin Bonds was related to the measured μTBs. Although Etch-and-Rinse bonds showed higher values at all times, the meta-analysis found no difference in longevity of the two types of bonds at the examined aging times. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Causes of death among crack cocaine users Causa mortis em usuários de crack

    Directory of Open Access Journals (Sweden)

    Marcelo Ribeiro

    2006-09-01

    Full Text Available OBJECTIVE: The study accompanied 131 crack-cocaine users over a 5-year period, and examined mortality patterns, as well as the causes of death among them. METHOD: All patients admitted to a detoxification unit in Sao Paulo between 1992 and 1994 were interviewed during two follow-up periods: 1995-1996 and 1998-1999. RESULTS: After 5 years, 124 patients were localized (95%. By the study endpoint (1999, 23 patients (17.6% had died. Homicide was the most prevalent cause of death (n = 13. Almost one third of the deaths were due to the HIV infection, especially among those with a history of intravenous drug use. Less than 10% died from overdose. CONCLUSIONS: The study suggests that the mortality risk among crack cocaine users is greater than that seen in the general population, being homicide and AIDS the most common causes of death among such individuals.OBJETIVO: O estudo acompanhou, por cinco anos, um grupo de 131 usuários de crack e observou os padrões de mortalidade, bem como as causas mortis entre esses. MÉTODO: Todos os pacientes que se internaram em um serviço de desintoxicação, localizado no município de São Paulo, entre 1992-1994 foram entrevistados em duas ocasiões: 1995-1996 e 1998-1999. RESULTADOS: Após cinco anos, 124 pacientes foram localizados (95%. Vinte e três pacientes (17,6% haviam morrido ao final do quinto ano de seguimento, sendo os homicídios a causa mortis mais prevalente (n = 13. Quase um terço dos pacientes morreu devido à infecção pelo vírus da imunodeficiência adquirida (HIV, especialmente aqueles com antecedentes pessoais de uso de drogas endovenosas. Menos de 10% dos pacientes morreu de overdose. CONCLUSÕES: O estudo sugere que os usuários de crack têm maior risco de morte do que a população geral, sendo os homicídios e a AIDS as causas mais observadas.

  1. Infecciones como causa de ingreso urgente en adultos en un hospital terciario

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    Miriam Saiz-Rodríguez

    2017-01-01

    Full Text Available OBJETIVO: Estudiar la prevalencia de las enfermedades infecciosas que son atendidas en el Servicio de Urgencias Hospitalario (SUH y que requieren ingreso hospitalario, así como identificar los principales agentes causales y describir el tratamiento y evolución de los pacientes. MÉTODO Estudio observacional retrospectivo que evalúa todos los pacientes que requieren ingreso urgente en un hospital terciario durante el mes de Marzo de 2016. Se recogieron como variables: enfermedades concomitantes, agentes causales, cultivos realizados, resistencias antibióticas y tratamiento prescrito. Las infecciones se clasificaron en: urinarias, respiratorias, intraabdominales, infección de piel y partes blandas, neurológicas, y otras. RESULTADOS Ingresaron un total de 903 pacientes durante este periodo. De estos, se consideró que el 36,2% podían tener una causa infecciosa. La edad media fue de 72,3 años y la estancia media en el hospital de 9,6 días. Las infecciones predominantes fueron respiratorias (47,2%, urinarias (19% e intraabdominales (18,1%. El 46,5% de las pruebas microbiológicas fueron positivas, siendo E. coli el principal agente causal (22,3%. Los perfiles de sensibilidad de los aislados fueron similares a los esperados, excepto para K. pneumoniae (50% resistente a fluoroquinolonas y amoxicilina-clavulánico. Los antibióticos predominantemente prescritos fueron β-lactámicos (51,2% y fluoroquinolonas (25,1%. La mortalidad fue del 7,3%, siendo la edad y presentar criterios de sepsis factores de riesgo asociados. CONCLUSIONES: Las infecciones son una de las principales causas de ingreso hospitalario y suponen un alto porcentaje de la atención sanitaria que se presta en el SUH. Nuestro estudio demuestra que la edad y los criterios de sepsis son factores cruciales asociados a la mortalidad de los pacientes. Este es el primer estudio que analiza cuantos ingresos a través del SUH se deben a una causa infecciosa.

  2. Darwin y la imposibilidad de causas finales en la biología

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    Corral Cuartas Álvaro

    2009-12-01

    Full Text Available La teoría de la selección natural propuesta por Charles Darwin en su obra El Origen de las Especies no sólo colocó las bases para una explicación coherente de los hechos fundamentales de la biología (el origen común de los seres vivos, la diversidad de individuos y especies y la transmisión de características hereditarias, sino que además introduce maneras nuevas de hacer filosofía. La teoría de la selección natural hace superflua cualquier posibilidad de apelar a explicaciones de tipo finalista en la ciencia. Desde Aristóteles se conocen cuatro tipos de causa: la material, la formal, la eficiente y la final. Aunque la causa eficiente es el paradigma de explicación por excelencia de las ciencias empíricas, la causa final sigue desempeñando un papel explicativo, por cuanto parece estar arraigada en nuestra estructura humana de pensamiento y la tendencia a presentar explicaciones finalistas sigue siendo recalcitrante. Quizá por estar los seres humanos tan familiarizados con la complejidad inherente a los procesos de diseño en las artes y en la técnica, suponemos por vía de analogía que la naturaleza en su complejidad exige la presencia y acción de un diseñador inteligente. Kant en la Crítica de la facultad de juzgar hace una defensa del carácter “irrenunciable” de este modelo explicativo. Para controvertir esta opinión, me apoyaré, en recientes investigaciones de Richard Dawkins y de otros biólogos contemporáneos para mostrar con la evolución de ojos en la naturaleza que el surgimiento de órganos de alta complejidad puede ser explicado sin

  3. DARWIN Y LA IMPOSIBILIDAD DE CAUSAS FINALES EN LA BIOLOGÍA

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    ÁLVARO CORRAL CUARTAS

    2009-01-01

    Full Text Available La teoría de la selección natural propuesta por Charles Darwin en su obra El origen de las especies no solo colocó las bases para una explicación coherente de los hechos fundamentales de la biología (el origen común de los seres vivos, la diversidad de individuos y especies y la transmisión de características hereditarias, sino que además introdujo maneras nuevas de hacer filosofía. La teoría de la selección natural hace superflua cualquier posibilidad de apelar a explicaciones de tipo finalista en la ciencia. Desde Aristóteles se conocen cuatro tipos de causa: la material, la formal, la eficiente y la final. Aunque la causa eficiente es el paradigma de explicación por exce- lencia de las ciencias naturales, la causa final sigue desempeñando un papel explicativo, por cuanto parece estar arraigada en nuestra estructura humana de pensamiento y la tendencia a presentar explicaciones finalistas sigue siendo recalcitrante. Quizá por estar los seres humanos tan familiarizados con la complejidad inherente a los procesos de diseño en las artes y en la técnica y quizá por la circunstancia de que los seres humanos organizamos casi todas nuestras acciones en torno a propósitos, es decir, a la definición de unos fines para los cuales buscamos unos medios, suponemos por vía de analogía que la naturaleza en su complejidad exige la presencia y acción de un diseñador inteligente. Kant en la Crítica de la facultad de juzgar hace una defensa del carácter “irrenunciable al género humano” de este modelo explicativo. Para contro- vertir esta opinión milenaria, me apoyaré, en investigaciones recientes de Richard Dawkins y de otros biólogos contemporáneos para mostrar con la evolución de ojos en la naturaleza que el surgimiento de órganos de alta complejidad puede ser explicado sin problema con la teoría de la selección natural propuesta por Darwin en 1859.

  4. Effect of dentin adhesives used as sealers and provisional cementation on bond strength of a resin cement to dentin.

    Science.gov (United States)

    Chieffi, Nicoletta; Sadek, Fernanda; Monticelli, Francesca; Goracci, Cecilia; Grandini, Simone; Davidson, Carel; Tay, Franklin R; Ferrari, Marco

    2006-04-01

    To evaluate the effects of dentin adhesives employed as resin sealers and provisional cementation on the bond strengths of a resin cement to dentin. A two-step etch-and-rinse adhesive (Excite DSC--Group 1) and two-step self-etch adhesive (AdheSE--Group 2) were applied to exposed dentin surfaces prepared from human molars (N=4). Water was used instead of a resin sealer in control Groups 3 and 4. A eugenol-free provisional cement (except for Group 4) was applied to the treated surfaces. After storing in distilled water for 1 week, the provisional cement was removed and cylindrical composite blocks were luted with a resin cement (Variolink II). 0.9 x 0.9 mm sticks were produced from these luted specimens for microtensile bond testing and SEM examination. One-way ANOVA revealed that neither the resin sealer nor the temporary eugenol-free cement had a negative effect on the final bond strength (P> 0.05). Mixed failures were predominantly identified from SEM.

  5. Effect of dentin biomodifiers on the immediate and long-term bond strengths of a simplified etch and rinse adhesive to dentin

    Directory of Open Access Journals (Sweden)

    Payal Singh

    2017-07-01

    Full Text Available Objectives This in vitro study evaluated the effect of dentin biomodifiers on the immediate and long-term bond strengths of a simplified etch and rinse adhesive to dentin. Materials and Methods Flat coronal dentin surfaces were prepared in 120 extracted human molars. Teeth were randomly divided into 5 groups (n = 24 according to 5 different surface pre-treatments: No pre-treatment (control; 1M carbodiimide (EDC; 0.1% epigallocatechin-3-gallate (EGCG; 2% minocycline (MI; 10% sodium ascorbate (SA. After surface pre-treatment, adhesive (Adper Single Bond 2 [SB], 3M ESPE was applied. Composite was applied into transparent plastic tubes (2.5 mm in diameter, which was placed over the bonded dentin surface. From each group, 10 samples were subjected to shear bond strength (SBS evaluation at 24 hours (immediate and remaining 10 samples were tested after 6 months (delayed. Additionally, 4 samples per group were subjected to scanning electron microscopic analysis for observation of resin-dentin interface. The data were statistically analysed with Shaperio‑Wilk W test, 2-way analysis of variance (ANOVA, and post hoc Tukey's test. Results At 24 hours, SBS of all surface pre-treatment groups were comparable with the control group, with significant differences found between EDC and SA groups only (p = 0.009. After 6 months storage, EDC, EGCG, and MI pre-treatments preserved the resin-dentin bond strength with no significant fall. Conclusions Dentin pre-treatment with all the dentin biomodifiers except SA resulted in significant preservation of resin-dentin bond over 6 months storage period, without negatively affecting the immediate bond strength of the etch and rinse adhesive tested.

  6. Effect of dentin biomodifiers on the immediate and long-term bond strengths of a simplified etch and rinse adhesive to dentin.

    Science.gov (United States)

    Singh, Payal; Nagpal, Rajni; Singh, Udai Pratap

    2017-08-01

    This in vitro study evaluated the effect of dentin biomodifiers on the immediate and long-term bond strengths of a simplified etch and rinse adhesive to dentin. Flat coronal dentin surfaces were prepared in 120 extracted human molars. Teeth were randomly divided into 5 groups (n = 24) according to 5 different surface pre-treatments: No pre-treatment (control); 1M carbodiimide (EDC); 0.1% epigallocatechin-3-gallate (EGCG); 2% minocycline (MI); 10% sodium ascorbate (SA). After surface pre-treatment, adhesive (Adper Single Bond 2 [SB], 3M ESPE) was applied. Composite was applied into transparent plastic tubes (2.5 mm in diameter), which was placed over the bonded dentin surface. From each group, 10 samples were subjected to shear bond strength (SBS) evaluation at 24 hours (immediate) and remaining 10 samples were tested after 6 months (delayed). Additionally, 4 samples per group were subjected to scanning electron microscopic analysis for observation of resin-dentin interface. The data were statistically analysed with Shaperio‑Wilk W test, 2-way analysis of variance (ANOVA), and post hoc Tukey's test. At 24 hours, SBS of all surface pre-treatment groups were comparable with the control group, with significant differences found between EDC and SA groups only (p = 0.009). After 6 months storage, EDC, EGCG, and MI pre-treatments preserved the resin-dentin bond strength with no significant fall. Dentin pre-treatment with all the dentin biomodifiers except SA resulted in significant preservation of resin-dentin bond over 6 months storage period, without negatively affecting the immediate bond strength of the etch and rinse adhesive tested.

  7. Mortalidad por causa externas: un problema de salud pública. Argentina, Chile y Colombia. 2000-2008

    Directory of Open Access Journals (Sweden)

    Doris Cardona Arango

    2013-01-01

    Full Text Available Se realizó un estudio descriptivo de la mortalidad por causas externas en la población argentina, chilena y colombiana durante el período 2000-2008. Se analizaron las muertes por homicidios, suicidios y accidentes de tránsito, en función de la edad y sexo. Se observó una reducción del riesgo de morir por estas causas en el segundo trienio. Hubo diferencias en la mortalidad por sexo y edad dependiendo la causa externa de muerte. Los mayores niveles de mortalidad correspondieron a los homicidios, seguidos por los accidentes de tránsito y por último los suicidios. Se registró sobremortalidad masculina en los tres países seleccionados.

  8. Mortalidad por causas externas: un problema de salud pública. Argentina, Chile y Colombia. 2000- 2008

    Directory of Open Access Journals (Sweden)

    Doris Cardona Arango

    2013-01-01

    Full Text Available Se realizó un estudio descriptivo de la mortalidad por causas externas en la población argentina, chilena y colombiana durante el período 2000-2008. Se analizaron las muertes por homicidios, suicidios y accidentes de tránsito, en función de la edad y sexo. Se observó una reducción del riesgo de morir por estas causas en el segundo trienio. Hubo diferencias en la mortalidad por sexo y edad dependiendo la causa externa de muerte. Los mayores niveles de mortalidad correspondieron a los homicidios, seguidos por los accidentes de tránsito y por último los suicidios. Se registró sobremortalidad masculina en los tres países seleccionados.

  9. Detección por GC-MS de trimetilamina como causa del mal olor

    OpenAIRE

    López Grimau, Víctor; Gutiérrez Bouzán, Mª Carmen

    2005-01-01

    En este trabajo se utiliza la cromatografía de gases acoplada a la espectrometría de masas para determinar la causa del olor desagradable que se desprende de un tejido estampado. El análisis se lleva a cabo directamente sobre el artículo textil, empleando la técnica de inyección del espacio en cabeza, que consiste en una extracción sólido-gas seguida de la inyección del aire directamente en la columna cromatográfica. En el tejido analizado, se detectó la presencia de dos aminas volátiles. Con...

  10. Causas psicosociales de la deserción universitaria”

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    Lizeth Reyes Ruiz

    2012-07-01

    Full Text Available Este artículo presenta las causas psicosociales de la deserción estudiantil del programa de Psicología de una Universidad de Barranquilla entre el 2009 y 2011. De un total de 65 personas, la muestra fue de 16 personas que cumplían con los criterios de selección. Se revisó la información existente en la Institución acerca de las pruebas MMPI y RAVEN, las pruebas saber 11, aspectos financieros, familiares y académicos. Los resultados muestran la correlación existente entre estas variables y la deserción universitaria.

  11. Diagnóstico de policitemia absoluta como posible causa de episodios convulsivos en un perro

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    Sandra Acevedo T.

    2010-12-01

    Full Text Available Se expone el caso de un perro poodle de 3 años de edad, el cual hace un año comenzó a convulsionar esporádicamente, principalmente después de hacer ejercicio y en algunas ocasiones presentó temblor generalizado. Al examen clínico realizado se observó mucosas orales y oculares hiperémicas. Al realizar los exámenes paraclínicos complementarios se encontró en hemogramas seriados un aumento marcado del hematocrito y la hemoglobina con niveles de proteínas plasmáticas en rangos normales, y una eritropoyectina 10 veces por debajo del rango normal. Se realizó ecografía abdominal y evaluación cardiaca. El diagnóstico fue de policitemia absoluta como la causa de las convulsiones.

  12. Hepatocarcinoma como causa de abdome agudo em adolescente: relato de caso

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    João Augusto dos Santos Martines

    2012-08-01

    Full Text Available O carcinoma hepatocelular (CHC é pouco prevalente nos países ocidentais, porém é um dos tumores mais freqüentes na Ásia e a quinta causa de câncer no mundo.É relatado um caso de adolescente do sexo feminino sem fatores de risco para um tumor extremamente agressivo, internada no Hospital Universitário da Universidade de São Paulo. A apresentação clínica foi de abdome agudo secundário a sangramento para cavidade peritoneal por ruptura do tumor evidenciado através de tomografia computorizada multidetectores (TCMD confirmado por laparotomia exploradora e biópsia hepática e tratada com rafia hemostática do parênquima hepático.

  13. CAUSAS DE LA SATISFACCIÓN LABORAL EN UNA ORGANIZACIÓN COMERCIALIZADORA MAYORISTA

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    PEDRO MANUEL ZAYAS AGÜERO

    2015-01-01

    Full Text Available Este estudio tiene como objetivo determinar las causas que influyen en la satisfacción laboral en una comercializadora mayorista, permitiendo establecer las estrategias y las acciones para lograr un proceso de mejora continua de la organización. En la metodología se emplearon técnicas como: escalas, encuestas, entrevistas y observación directa, todas interrelacionadas, procediéndose a la triangulación de los resultados. Se validaron por expertos los instrumentos diseñados. El procesamiento estadístico se hizo usando el software estadístico SPSS. En los resultados de la investigación se detectaron los aspectos que inhibieron la satisfacción laboral en los empleados, así como el conjunto predominante de dimensiones e indicadores que identifican las principales insuficiencias existentes.

  14. Pseudotumor inflamatorio de Ciego como causa de abdomen agudo: Presentación de 3 casos

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    Alexis Cantero Ronquillo

    2001-09-01

    Full Text Available Se presentan 3 enfermos con tumores en fosa ilíaca derecha con cuadros abdominales mixtos oclusivos y peritoneales, donde se hizo necesario realizar hemicolectomía derecha por tumores que afectaban ciego e íleo terminal, sin hallar rastros de apéndice cecal, y habían sido procesos inflamatorios de la misma causa inicial de la enfermedad presente3 patients with tumors on the right iliac fossa with mixed occlusive and peritoneal abdominal pictures, where it was necessary to perform right hemicolectomy due to tumors that affected the cecum and the terminal ileus, without finding signs of cecal appendix. Inflammatory processes of the same initial cause of the disease were also observed

  15. Los conflictos intraestatales contemporáneos: una aproximación a sus causas estructurales

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    Hugo F. Guerrero Sierra

    2012-07-01

    Full Text Available La propuesta del presente artículo es plantear un análisis conceptual en torno al fenómeno del conflicto social, específicamente cuando este deriva en dinámicas de orden violento. Del mismo modo, una vez establecida esta puntualización conceptual, y a través de la alusión a casos particulares, se presenta un breve recorrido por diferentes aportes que, desde el mundo de la academia, se han venido planteando respecto a la conexión entre el fenómeno de los conflictos intraestatales y sus posibles causas estructurales.

  16. Topical application of lithium chloride on the pulp induces dentin regeneration.

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    Kazuya Ishimoto

    Full Text Available We herein describe a novel procedure for dentin regeneration that mimics the biological processes of tooth development in nature. The canonical Wnt signaling pathway is an important regulator of the Dentin sialophosphoprotein (Dspp expression. Our approach mimics the biological processes underlying tooth development in nature and focuses on the activation of canonical Wnt signaling to trigger the natural process of dentinogenesis. The coronal portion of the dentin and the underlying pulp was removed from the first molars. We applied lithium chloride (LiCl, an activator of canonical Wnt signaling, on the amputated pulp surface to achieve transdifferentiation toward odontoblasts from the surrounding pulpal cells. MicroCT and microscopic analyses demonstrated that the topical application of LiCl induced dentin repair, including the formation of a complete dentin bridge. LiCl-induced dentin is a tubular dentin in which the pulp cells are not embedded within the matrix, as in primary dentin. In contrast, a dentin bridge was not induced in the control group treated with pulp capping with material carriers alone, although osteodentin without tubular formation was induced at a comparatively deeper position from the pulp exposure site. We also evaluated the influence of LiCl on differentiation toward odontoblasts in vitro. In the mDP odontoblast cell line, LiCl activated the mRNA expression of Dspp, Axin2 and Kallikrein 4 (Klk4 and downregulated the Osteopontin (Osp expression. These results provide a scientific basis for the biomimetic regeneration of dentin using LiCl as a new capping material to activate dentine regeneration.

  17. Bonding of adhesives to Er:YAG laser-treated dentin.

    Science.gov (United States)

    Koliniotou-Koumpia, Eugenia; Kouros, Pantelis; Zafiriadis, Lazaros; Koumpia, Effimia; Dionysopoulos, Pavlos; Karagiannis, Vassilis

    2012-01-01

    The shear bond strength of adhesives applied to dentin was investigated after irradiation with an erbium-doped yttrium aluminum garnet (Er:YAG) laser. Superficial and deep dentin specimens from human molars were treated either with carbide bur or an Er:YAG laser. Two etch and rinse adhesives (Single Bond and XP Bond) and two self-etch adhesives (Prompt L-Pop and Xeno III) were employed to bond the composite. Shear bond strength (SBS) was determined after storage in water for 24 h using a universal testing machine with a crosshead speed of 0.5 mm/min. Failure patterns and modes were analyzed and evaluated using a stereomicroscope. In addition, samples were processed for Scanning Electron Microscopy SEM evaluation. A linear mixed model was used, and pairwise comparisons were made using the Bonferroni test. Results showed significant differences between the levels of dentin treatment (p=.01) in carbide bur-cut dentin and lased dentin, as well as significant interaction effects due to the depth of dentin and the bonding system used. The etch and rinse adhesives bonded less effectively with lased dentin than with carbide bur-cut dentin, while self-etch adhesives bonded equally well with lased and bur-cut superficial dentin but much less effectively with lased deep dentin than with bur-cut deep dentin. SEM revealed a predominantly adhesive failure mode in laser-ablated fractured specimens, while a mixed failure mode was apparent in the bur-cut fractured specimens. Cavities prepared by laser seem less receptive to adhesive procedures than conventional bur-cut cavities.

  18. Bonding of adhesives to Er:YAG laser-treated dentin

    Science.gov (United States)

    Koliniotou-Koumpia, Eugenia; Kouros, Pantelis; Zafiriadis, Lazaros; Koumpia, Effimia; Dionysopoulos, Pavlos; Karagiannis, Vassilis

    2012-01-01

    Objective: The shear bond strength of adhesives applied to dentin was investigated after irradiation with an erbium-doped yttrium aluminum garnet (Er:YAG) laser. Methods: Superficial and deep dentin specimens from human molars were treated either with carbide bur or an Er:YAG laser. Two etch and rinse adhesives (Single Bond and XP Bond) and two self-etch adhesives (Prompt L-Pop and Xeno III) were employed to bond the composite. Shear bond strength (SBS) was determined after storage in water for 24 h using a universal testing machine with a crosshead speed of 0.5 mm/min. Failure patterns and modes were analyzed and evaluated using a stereomicroscope. In addition, samples were processed for Scanning Electron Microscopy SEM evaluation. A linear mixed model was used, and pairwise comparisons were made using the Bonferroni test. Results: Results showed significant differences between the levels of dentin treatment (p=.01) in carbide bur-cut dentin and lased dentin, as well as significant interaction effects due to the depth of dentin and the bonding system used. The etch and rinse adhesives bonded less effectively with lased dentin than with carbide bur-cut dentin, while self-etch adhesives bonded equally well with lased and bur-cut superficial dentin but much less effectively with lased deep dentin than with bur-cut deep dentin. SEM revealed a predominantly adhesive failure mode in laser-ablated fractured specimens, while a mixed failure mode was apparent in the bur-cut fractured specimens. Conclusions: Cavities prepared by laser seem less receptive to adhesive procedures than conventional bur-cut cavities. PMID:22229003

  19. Effect of propolis gel on the in vitro reduction of dentin permeability

    Directory of Open Access Journals (Sweden)

    Silvia Helena de Carvalho Sales-Peres

    2011-08-01

    Full Text Available OBJECTIVE: The aim of this study was to evaluate the capacity of potassium oxalate, fluoride gel and two kinds of propolis gel to reduce the hydraulic conductance of dentin, in vitro. MATERIAL AND METHODS: The methodology used for the measurement of hydraulic conductance of dentin in the present study was based on a model proposed in literature. Thirty-six 1-mm-thick dentin discs, obtained from extracted human third molars were divided into 4 groups (n=9. The groups corresponded to the following experimental materials: GI-10% propolis gel, pH 4.1; GII-30% propolis gel; GIII-3% potassium oxalate gel, pH 4,1; and GIV-1.23% fluoride gel, pH 4.1, applied to the dentin under the following surface conditions: after 37% phosphoric acid and before 6% citric acid application. The occluding capacity of the dentin tubules was evaluated using scanning electron microscopy (SEM at ×500, ×1,000 and ×2,000 magnifications. Data were analyzed statistically by two-way ANOVA and Tukey's test at 5% significance level. RESULTS: Groups I, II, III, IV did not differ significantly from the others in any conditions by reducing in hydraulic conductance. The active agents reduced dentin permeability; however they produced the smallest reduction in hydraulic conductance when compared to the presence of smear layer (P<0.05. The effectiveness in reducing dentin permeability did not differ significantly from 10% or 30% propolis gels. SEM micrographs revealed that dentin tubules were partially occluded after treatment with propolis. CONCLUSIONS: Under the conditions of this study, the application of 10% and 30% propolis gels did not seem to reduce the hydraulic conductance of dentin in vitro, but it showed capacity of partially obliterating the dentin tubules. Propolis is used in the treatment of different oral problems without causing significant great collateral effects, and can be a good option in the treatment of patients with dentin sensitivity.

  20. Causas e conseqüências de quedas de idosos atendidos em hospital público

    Directory of Open Access Journals (Sweden)

    Fabrício Suzele Cristina Coelho

    2004-01-01

    Full Text Available OBJETIVO: Investigar a história da queda relatada por idosos, identificando fatores possivelmente relacionados, assim como local de ocorrência, causas e conseqüências. MÉTODOS: A amostra da investigação constou de 50 idosos, de ambos os sexos, com idade de 60 anos ou mais, residentes em Ribeirão Preto, SP, que haviam sido atendidos em duas unidades de um hospital público. Foram consultados prontuários e realizadas visitas domiciliares para aplicação de um questionário estruturado com perguntas abertas, fechadas e mistas relativas à queda. RESULTADOS: Os dados obtidos mostraram uma realidade que não difere substancialmente daquela encontrada em outros países. A maioria das quedas ocorreu entre idosos do sexo feminino (66%, com idade média de 76 anos, no próprio lar do idoso (66%. As causas foram principalmente relacionadas ao ambiente físico (54%, acarretando sérias conseqüências aos idosos, sendo as fraturas as mais freqüentes (64%. A queda teve grande impacto na vida do idoso no que se refere às atividades da vida diária. Provocou maior dependência para a realização de atividades como: deitar/levantar-se, caminhar em superfície plana, cortar unhas dos pés, tomar banho, caminhar fora de casa, cuidar das finanças, fazer compras, usar transporte coletivo e subir escadas. CONCLUSÕES: O estudo demonstrou que a queda ocorrida entre os idosos traz sérias conseqüências físicas, psicológicas e sociais, reforçando a necessidade de prevenção da queda, garantindo ao idoso melhor qualidade de vida, autonomia e independência.

  1. Causas e conseqüências de quedas de idosos atendidos em hospital público

    Directory of Open Access Journals (Sweden)

    Suzele Cristina Coelho Fabrício

    2004-02-01

    Full Text Available OBJETIVO: Investigar a história da queda relatada por idosos, identificando fatores possivelmente relacionados, assim como local de ocorrência, causas e conseqüências. MÉTODOS: A amostra da investigação constou de 50 idosos, de ambos os sexos, com idade de 60 anos ou mais, residentes em Ribeirão Preto, SP, que haviam sido atendidos em duas unidades de um hospital público. Foram consultados prontuários e realizadas visitas domiciliares para aplicação de um questionário estruturado com perguntas abertas, fechadas e mistas relativas à queda. RESULTADOS: Os dados obtidos mostraram uma realidade que não difere substancialmente daquela encontrada em outros países. A maioria das quedas ocorreu entre idosos do sexo feminino (66%, com idade média de 76 anos, no próprio lar do idoso (66%. As causas foram principalmente relacionadas ao ambiente físico (54%, acarretando sérias conseqüências aos idosos, sendo as fraturas as mais freqüentes (64%. A queda teve grande impacto na vida do idoso no que se refere às atividades da vida diária. Provocou maior dependência para a realização de atividades como: deitar/levantar-se, caminhar em superfície plana, cortar unhas dos pés, tomar banho, caminhar fora de casa, cuidar das finanças, fazer compras, usar transporte coletivo e subir escadas. CONCLUSÕES: O estudo demonstrou que a queda ocorrida entre os idosos traz sérias conseqüências físicas, psicológicas e sociais, reforçando a necessidade de prevenção da queda, garantindo ao idoso melhor qualidade de vida, autonomia e independência.

  2. Causas de morte em vacas leiteiras no Rio Grande do Sul

    Directory of Open Access Journals (Sweden)

    Lauren Santos de Mello

    Full Text Available RESUMO: As causas de morte em vacas leiteiras no Rio Grande do Sul foram analisadas através de um estudo retrospectivo dos protocolos de necropsia de 600 vacas leiteiras examinadas entre os anos de 1998-2012. Do total de vacas analisadas 67,5% eram oriundas da Região Metropolitana de Porto Alegre, seguida das Regiões Nordeste Rio-Grandense 12,4% e Centro Oriental Rio-Grandense 10,4%. Quanto às raças, 76,5% eram holandesas, 9,8% Jersey e 13,7% misturas dessas raças. O diagnóstico definitivo foi possível em 85,8% dos casos. A categoria de doenças inflamatórias e parasitárias foi a principal causa de morte com 48,2% dos casos conclusivos, seguida por neoplasias (17,5%, doenças tóxicas e toxi-infecções (15,9%, doenças nutricionais e metabólicas (8,5%, doenças causadas por agentes físicos (7,4% e outras doenças (2,5%. As principais enfermidades diagnosticadas em cada categoria foram: tristeza parasitária bovina (120 casos, linfoma (77 casos, intoxicação por Senecio spp. (23 casos, retículo pericardite traumática (19 casos, cetose e timpanismo (11 casos cada uma e fulguração (5 casos.

  3. Causas de la deserción en la hospitalización parcial de adolescentes

    Directory of Open Access Journals (Sweden)

    Juana Velázquez Argota

    1997-04-01

    Full Text Available Se presentan los resultados del estudio de las causas de deserción de 23 adolescentes que funcionan al nivel neurótico en régimen de hospitalización parcial. Se distingue más de una causa de deserción, tanto en el grupo en que la deserción se produjo en la primera semana de hospitalización (9 casos, como en los de estadía más prolongada (14 casos, y se destacan la vaguedad de la conciencia de enfermedad, la pretensión de establecer una alianza psicopática con el terapeuta y la no formulación por el terapeuta de los objetivos de ingreso con claridad. Para prevenir la deserción se recomienda, antes de decidir el ingreso, explicar los objetivos de la hospitalización, trabajar en el desarrollo de la conciencia de enfermedad y el manejo psicoterapéutico cuidadoso de la propuesta de alianza psicopática.The results of the study about the causes of the dropout of 23 adolescents functioning at the neurotic level in a partial hospitalization regimen are presented. There is more than one cause of dropout, both in the group where it took place during the first week of hospitalization (9 cases and in those with a longer stay. It is stressed the vagueness of the consciousness of the disease, the pretension to establish a psychopathic alliance with the therapist, and the unclear formulation on the part of the therapist of the objectives of admission. To prevent the dropout, it is recommended, before deciding the admission, to explain the objectives of hospitalization, to work on the development of the conciousness of the disease, and the careful psychotherapeutic management of the proposal of the psychopathic alliance.

  4. Creencias de Estudiantes de Secundaria Españoles y Mexicanos sobre las Causas de la Obesidad

    OpenAIRE

    Rigoberto León-Sánchez

    2015-01-01

    Se exploraron, a través de un cuesti onario diseñado ex profeso , las creencias sobre las causas de la obesidad en una muestra de 142 estudiantes de segundo y tercer grados de secundaria (71 españoles y 71 mexicanos). El rango de edad de los participantes fue de 13 a 16 años ( M = 14.02, DE = . 846) . Los participantes consideraron que la Voluntad y la Personalidad son las causas más importantes de la obesidad, X 2 (5, 142) = 265.353, p < .001, en...

  5. ¿Fue una meningitis tuberculosa terminal la causa de muerte de Simón Bolívar?

    OpenAIRE

    Fernando Guzmán Mora

    2014-01-01

    Simón Bolívar. Mucho se ha especulado sobre la causa de su uerte. Algunos han llegado al extremo de acusar a sus propios médicos de haber administrads medicamentos equivocados para los conocimientos de aquel entonces. Otros han mencionado la malaria como la enfermedad que causó su deceso. Las opiniones no son iguales y encuentran particular divergencia tres teorías sobre la causa última de su muerte: El paludismo, el absceso hepático amebiano y la tuberculosis.

  6. ¿Fue una meningitis tuberculosa terminal la causa de muerte de Simón Bolívar?

    Directory of Open Access Journals (Sweden)

    Fernando Guzmán Mora

    2014-09-01

    Full Text Available Simón Bolívar. Mucho se ha especulado sobre la causa de su uerte. Algunos han llegado al extremo de acusar a sus propios médicos de haber administrads medicamentos equivocados para los conocimientos de aquel entonces. Otros han mencionado la malaria como la enfermedad que causó su deceso. Las opiniones no son iguales y encuentran particular divergencia tres teorías sobre la causa última de su muerte: El paludismo, el absceso hepático amebiano y la tuberculosis.

  7. Effect of chemomechanical caries removal on bonding of resin-modified glass ionomer cement adhesives to caries-affected dentine.

    Science.gov (United States)

    Hamama, Hhh; Yiu, Cky; Burrow, M F

    2015-06-01

    This study evaluated the effect of: (1) chemomechanical caries removal (CMCR); (2) dentine surface treatments and (3) dentine substrates on adhesion of resin-modified glass ionomer cement (RMGIC) adhesives. One hundred and twenty permanent molars exhibiting moderate cavitation on the occlusal surface into dentine were used. Seventy-five carious molars were used for bond strength testing; the remaining 45 for micromorphological evaluation of the bonded interface. Caries was excavated with NaOCl-based CMCR (Carisolv), enzyme-based CMCR (Papacarie), or conventional rotary caries removal methods. Dentine surface treatment was performed using 37% phosphoric acid, 25-30% PAA or 20% PAA + 3% AlCl3 . Three-way ANOVA revealed that all three factors 'caries removal methods', 'dentine surface treatments' and 'dentine substrates' did not significantly affect bond strength (p > 0.05). Scanning electron microscopy micrographs showed that the acid-base resistant layer was thicker in caries-affected dentine compared to sound dentine. NaOCl- and enzyme-based CMCR methods have no adverse effect on adhesion of RMGIC adhesives to sound and caries-affected dentine. Dentine surface treatment with 37% phosphoric acid for 5 s has no negative effect on bonding of RMGIC adhesives to dentine compared with using polyacrylic acid for 10 s. RMGIC adhesives bonded well to both sound and caries-affected dentine. © 2015 Australian Dental Association.

  8. In vitro tomographic image of human pulp-dentin complex: optical coherence tomography and histology.

    Science.gov (United States)

    Braz, Ana K S; Kyotoku, Bernardo B C; Gomes, Anderson S L

    2009-09-01

    Optical coherence tomography (OCT), a noninvasive imaging method, was used in this work to image the pulp-dentin complex. Pulp and dentin are integrally connected in the sense that physiologic and pathologic reactions in one of the tissues will also affect the other. An OCT system with 6-mum spatial resolution at 800 nm was used to image the pulp-dentin complex of in vitro samples. Five intact human maxillary premolars scheduled for surgical extraction were used in this in vitro study. The occlusal surfaces of teeth were polished with wet 600-, 1,000-, and 1,200-grit aluminum oxide abrasive paper perpendicular to the long axis of teeth, producing a plane on that surface. The images of pulp-dentin complex were taken by scanning the occlusal surface in a mesiodistal direction. The laser penetrated into the teeth structure and a tomographic image of pulp-dentin complex, parallel to the long axis of teeth, was obtained. Histological and OCT images were analyzed and compared. The results showed the capability of the OCT technique to generate images of the boundaries of pulp and its relation to the dentin. It could be clearly seen that the OCT image provided the insight into dentinal substrate about 0.65-mm deep (corrected for the dentin refractive index). OCT can be used in the future to prevent iatrogenic exposures of the pulp, complementing other existing methods, and will permit a more predictive prognosis of treatments.

  9. Penetration of sub-micron particles into dentinal tubules using ultrasonic cavitation.

    Science.gov (United States)

    Vyas, N; Sammons, R L; Pikramenou, Z; Palin, W M; Dehghani, H; Walmsley, A D

    2017-01-01

    Functionalised silica sub-micron particles are being investigated as a method of delivering antimicrobials and remineralisation agents into dentinal tubules. However, their methods of application are not optimised, resulting in shallow penetration and aggregation. The aim of this study is to investigate the impact of cavitation occurring around ultrasonic scalers for enhancing particle penetration into dentinal tubules. Dentine slices were prepared from premolar teeth. Silica sub-micron particles were prepared in water or acetone. Cavitation from an ultrasonic scaler (Satelec P5 Newtron, Acteon, France) was applied to dentine slices immersed inside the sub-micron particle solutions. Samples were imaged with scanning electron microscopy (SEM) to assess tubule occlusion and particle penetration. Qualitative observations of SEM images showed some tubule occlusion. The particles could penetrate inside the tubules up to 60μm when there was no cavitation and up to ∼180μm when there was cavitation. The cavitation bubbles produced from an ultrasonic scaler may be used to deliver sub-micron particles into dentine. This method has the potential to deliver such particles deeper into the dentinal tubules. Cavitation from a clinical ultrasonic scaler may enhance penetration of sub-micron particles into dentinal tubules. This can aid in the development of novel methods for delivering therapeutic clinical materials for hypersensitivity relief and treatment of dentinal caries. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Autoradiographic location of sensory nerve endings in dentin of monkey teeth

    Energy Technology Data Exchange (ETDEWEB)

    Byers, M.R.; Dong, W.K.

    1983-04-01

    We have used the autoradiographic method to locate trigeminal nerve endings in monkey teeth. The nerve endings were labeled in two adult female Macaca fascicularis by 20 hours of axonal transport of radioactive protein (/sup 3/H-L-proline). We found a few labeled axons in contralateral mandibular central incisors and one mandibular canine. In ipsilateral teeth, numerous myelinated and unmyelinated axons were labeled; they formed a few terminal branches in the roots but primarily branched in the crown to form the peripheral plexus of Raschkow and to terminate as free endings in the odontoblast layer, predentin, and as far as 120 micrometers into dentinal tubules. Electron microscopic autoradiography showed that the radioactive axonally transported protein was confined to sensory axons and endings; odontoblasts and dentin matrix were not significantly labeled. Labeled free nerve endings were closely apposed to odontoblasts in dentin but did not form distinctive junctions with them. Nerve endings were most numerous in the regular tubular dentin of the crown adjacent to the tip of the pulp horn, occurring in at least half of the dentinal tubules there. Our results show tha dentinal sensory nerve endings in primate teeth can be profuse, sparse, or absent depending on the location and structure of dentin and its adjacent pulp. When dentin was innervated, the tubules were straight and contained odontoblast processes, the predentin was wide, the odontoblast cell bodies were relatively columnar, and there was an adjacent cell-free zone and pulpal nerve plexus.

  11. Dentinal sensitivity among a selected group of young adults in Nigeria

    African Journals Online (AJOL)

    Participants experienced shocking sensation more on the left-side of the mouth. The most common ... Despite the negative functional and psychological impact among the participants, only a few sought dental professional care. Screening for dentinal ... on the populace. Key words: Diet, dentinal sensitivity, young adults ...

  12. Hora est 2. Is door amalgaam verkleurd dentine een geschikt substraat voor hechting van composiet?

    NARCIS (Netherlands)

    Scholtanus, J.D.

    After the removal of amalgam restorations, black staining of dentin is often observed, which is attributed to the penetration of corrosion products from amalgam. A study was carried out to determine whether this amalgam stained dentin is a proper substrate for bonding resin composites. A literature

  13. DSPP contains an IRES element responsible for the translation of dentin phosphophoryn.

    Science.gov (United States)

    Zhang, Y; Song, Y; Ravindran, S; Gao, Q; Huang, C C; Ramachandran, A; Kulkarni, A; George, A

    2014-02-01

    The major phosphoprotein in dentin is the aspartic acid and serine-rich protein called dentin phosphophoryn (DPP). DPP appears to be synthesized as a part of a larger compound protein, dentin sialophosphoprotein (DSPP). DSPP has never been isolated or detected in dentin extracts. It is now evident that DSPP is a chimeric protein composed of 3 parts: dentin sialoprotein (DSP), DPP, and dentin glycoprotein (DGP). Previous reports have suggested that the BMP1 protease is responsible for processing DSPP. However, unequal amounts of these products are present in the dentin matrix. Here, we provide evidence for an internal ribosome entry site in the DSPP gene that directs the synthesis of DPP. This mechanism would account for unequal amounts of intracellular DSP and DPP. The internal ribosomal entry site (IRES) activity varied in different cell types, suggesting the presence of additional regulatory elements during the translational regulation of DPP. Further, we provide evidence that DPP is transported to the extracellular matrix (ECM) through exosomes. Using tissue recombination and lentivirus-mediated gain-of-function approaches, we also demonstrate that DPP is essential for the formation of well-defined tooth structures with mineralized dentin matrix.

  14. Young's modulus of peritubular and intertubular human dentin by nano-indentation tests.

    Science.gov (United States)

    Ziskind, Daniel; Hasday, Moran; Cohen, Sidney R; Wagner, H Daniel

    2011-04-01

    The local Young modulus of dry dentin viewed as a hierarchical composite was measured by nano-indentation using two types of experiments, both in a continuous stiffness measurement mode. First, tests were performed radially along straight lines running across highly mineralized peritubular dentin sections and through less mineralized intertubular dentin areas. These tests revealed a gradual decrease in Young's modulus from the bulk of the peritubular dentin region where modulus values of up to ∼40-42GPa were observed, down to approximately constant values of ∼17GPa in the intertubular dentin region. A second set of nano-indentation experiments was performed on the facets of an irregular polyhedron specimen cut from the intertubular dentin region, so as to probe the modulus of intertubular dentin specimens at different orientations relative to the tubular direction. The results demonstrated that the intertubular dentin region may be considered to be quasi-isotropic, with a slightly higher modulus value (∼22GPa) when the indenting tip axis is parallel to the tubular direction, compared to the values (∼18GPa) obtained when the indenting tip axis is perpendicular to the tubule direction. Copyright © 2010 Elsevier Inc. All rights reserved.

  15. Microhardness Characteristics Value of Root canal Dentin After application With Different Types of EDTA

    OpenAIRE

    drg. Ph.D, Nurhayati NatsirSp.KG

    2016-01-01

    The Result Show there arae differences in dentin microhardness decrease significantly in all treatment group EDTA solution, Amountingto 13 667kg/mm2. This study aim to determine the charactheristics of the microhardness impairment root canal dentin after application with different types of EDTA.

  16. Effect of carbodiimide on the structural stability of resin/dentin interface.

    Science.gov (United States)

    Singh, Payal; Nagpal, Rajni; Singh, Udai Pratap; Manuja, Naveen

    2016-01-01

    Clinical longevity of composite resin restorations is a significant problem in adhesive dentistry. Most of the current simplified adhesives present good immediate bonding, but the bond strength gradually falls over a period due to biodegradation at the resin-dentin interface. Various strategies have been proposed to improve the durability of resin-dentin bond including the use of matrix metalloproteinases inhibitors and collagen cross-linkers, biomimetic remineralization, ethanol wet bonding, to improve the physical and mechanical properties of the bonding substrate, i.e., dentin. However, all are under preliminary research and without any conclusive evidence. Therefore, this paper addresses the current challenge in dental adhesion, i.e., poor durability of resin-dentin bond and introduces the concept of dentin biomodification as an alternative way for improving the long-term bonding effectiveness of current adhesives to dentin and also provides an overview of a synthetic collagen cross-linking agent carbodiimide (EDC) including its mechanism of action, literature review of studies evaluating EDC, variables associated with its use and its cytotoxicity. Search was performed across the electronic databases (PubMed, Ebsco host, and Google search engine) to identify manuscripts for inclusion, using the keywords: carbodiimide, dentin bonding, durability, resin-dentin interface, and collagen cross-linking. Thirty-five articles were finally included, and the last search was made in February 2016.

  17. TEMPERATURE-DEPENDENCE OF WATER TRANSPORT INTO THE MINERALIZED MATRIX OF FREEZE-DRIED HUMAN DENTIN

    NARCIS (Netherlands)

    VANDERGRAAF, ER; TENBOSCH, JJ

    1991-01-01

    Ten dentine sections cut perpendicular to the dentinal tubules from human mature non-carious third molars, were freeze-dried and then rehydrated by immersion in water at four temperatures, 10, 25, 40 and 70-degrees-C. The uptake of water by the sections was assessed as a function of rehydration

  18. Dentin Permeability of Carious Primary Teeth | Ulu Güzel | Nigerian ...

    African Journals Online (AJOL)

    Background: Many in vitro studies have used dentine permeability to evaluate the efficacy of various restorative and preventative procedures. The easiest way to evaluate dentine permeability is to calculate its hydraulic conductance (Lp) using fluid filtration methods. Research has examined electronic hydraulic

  19. Eroded dentin does not jeopardize the bond strength of adhesive restorative materials

    Directory of Open Access Journals (Sweden)

    Janaina Barros Cruz

    2012-08-01

    Full Text Available This in vitro study evaluated the bond strength of adhesive restorative materials to sound and eroded dentin. Thirty-six bovine incisors were embedded in acrylic resin and ground to obtain flat buccal dentin surfaces. Specimens were randomly allocated in 2 groups: sound dentin (immersion in artificial saliva and eroded dentin (pH cycling model - 3× / cola drink for 7 days. Specimens were then reassigned according to restorative material: glass ionomer cement (KetacTM Molar Easy Mix, resin-modified glass ionomer cement (VitremerTM or adhesive system with resin composite (Adper Single Bond 2 + Filtek Z250. Polyethylene tubes with an internal diameter of 0.76 mm were placed over the dentin and filled with the material. The microshear bond test was performed after 24 h of water storage at 37ºC. The failure mode was evaluated using a stereomicroscope (400×. Bond strength data were analyzed with two-way ANOVA and Tukey's post hoc tests (α = 0.05. Eroded dentin showed bond strength values similar to those for sound dentin for all materials. The adhesive system showed the highest bond strength values, regardless of the substrate (p < 0.0001. For all groups, the adhesive/mixed failure prevailed. In conclusion, adhesive materials may be used in eroded dentin without jeopardizing the bonding quality. It is preferable to use an etch-and-rinse adhesive system because it shows the highest bond strength values compared with the glass ionomer cements tested.

  20. Microtensile bond strength of three simplified adhesive systems to caries-affected dentin

    NARCIS (Netherlands)

    Scholtanus, J.D.; Purwanta, K.; Dogan, N.; Kleverlaan, C.J.; Feilzer, A.J.

    2010-01-01

    Purpose: The purpose of the study was to determine the microtensile bond strength of three different simplified adhesive systems to caries-affected dentin. Materials and Methods: Fifteen extracted human molars with primary carious lesions were ground flat until dentin was exposed. Soft

  1. Micro-mechanical bond strength tests for the assessment of the adhesion of GIC to dentine

    NARCIS (Netherlands)

    Bonifacio, C.C.; Shimaoka, A.M.; de Andrade, A.P.; Raggio, D.P.; van Amerongen, W.E.; de Carvalho, R.C.R.

    2012-01-01

    Background. The aim of this study is to critically evaluate the bond strength (BS) of Glass-Ionomer Cements (GIC) to dentine with microtensile (μTBS) and microshear (μSBS) BS tests by assessing their rankings and failure patterns. Methods. Samples were made on flat dentine surfaces and submitted to

  2. Shear bond strength of dentin and deproteinized enamel of AI mouse incisors

    Science.gov (United States)

    Pugach, M.K.; Ozer, F.; Mulmadgi, R.; Li, Y.; Suggs, C.; Wright, J.T.; Bartlett, J.D.; Gibson, C.W.; Lindemeyer, R.G.

    2014-01-01

    Purpose To investigate the adhesion through shear bond strength (SBS) testing of a resin composite bonded with a self-etching bonding system (SEB) to amelogenesis imperfecta (AI)-affected deproteinized mouse enamel or dentin; and to compare wild-type (WT), amelogenin null (AmelxKO) and matrix metalloproteinase-20 null (Mmp20KO) enamel and dentin phenotypes using microCT and nanoindentation. Methods Enamel incisor surfaces of WT, AmelxKO and Mmp20KO mice were treated with SEB with and without NaOCl and tested for SBS. Incisor dentin was also treated with SEB and tested for SBS. These surfaces were further examined by SEM. MicroCT and nanoindentation analyses were performed on mouse dentin and enamel. Data were analyzed for significance by ANOVA. Results Deproteinization did not improve SBS of SEB to these AI-affected enamel surfaces. SBS of AmelxKO teeth was similar in dentin and enamel; however, it was higher in Mmp20KO dentin. The nanohardness of knockout enamel was significantly lower than WT, while knockout dentin nanohardness was not different from WT. Conclusions Using animal AI models, it was demonstrated that enamel NaOCl deproteinization of hypoplastic and hypoplastic-hypomaturation enamel did not increase shear bond strength while removal of the defective enamel allowed optimal dentin bonding. PMID:25303500

  3. CLOSING OF DENTINAL TUBULES BY GLUTARDIALDEHYDE TREATMENT, A SCANNING ELECTRON-MICROSCOPY STUDY

    NARCIS (Netherlands)

    DIJKMAN, GEHM; JONGEBLOED, WL; DEVRIES, J; OGAARD, B; ARENDS, J

    The properties of dentin are strongly influenced by the so-called smear layer. This layer is always present on the dentin surface after cutting, drilling, sawing, etc. The smear layer can be removed by various chemical treatments, such as those of acid etching or ethylenediaminetetraacetic acid

  4. Bond strength of different resin cement and ceramic shades bonded to dentin.

    Science.gov (United States)

    Passos, Sheila Pestana; Kimpara, Estevão Tomomitsu; Bottino, Marco Antonio; Júnior, Gildo Coelho; Rizkalla, Amin S

    2013-10-01

    To evaluate the microtensile bond strength (MTBS) of ceramic cemented to dentin varying the resin cement and ceramic shades. Two VITA VM7 ceramic shades (Base Dentine 0M1 and Base Dentine 5M3) were used. A spectrophotometer was used to determine the percentage translucency of ceramic (thickness: 2.5 mm). For the MTBS test, 80 molar dentin surfaces were etched and an adhesive was applied. Forty blocks (7.2 x 7.2 x 2.5 mm) of each ceramic shade were produced and the ceramic surface was etched (10% hydrofluoric acid) for 60 s, followed by the application of silane and resin cement (A3 yellow and transparent). The blocks were cemented to dentin using either A3 or transparent cement. Specimens were photoactivated for 20 s or 40 s, stored in distilled water (37°C/24 h), and sectioned. Eight experimental groups were obtained (n = 10). Specimens were tested for MTSB using a universal testing machine. Data were statistically analyzed using ANOVA and Tukey's post-hoc tests (α cement that was photocured for 20 s exhibited the lowest MTBS, while the transparent cement that was photocured for 40 s presented the highest MTBS. For the 2.5-mm-thick 5M3 ceramic restorations, the MTBS of ceramic cemented to dentin significantly increased. The dual-curing cement Variolink II photocured for 40 s is not recommended for cementing the Base Dentine 5M3 feldspathic ceramic to dentin.

  5. Luting glass ceramic restorations using a selfadhesive resin cement under different dentin conditions

    Science.gov (United States)

    GUARDA, Guilherme B.; GONÇALVES, Luciano S.; CORRER, Américo B.; MORAES, Rafael R.; SINHORETI, Mário A.C.; CORRER-SOBRINHO, Lourenço

    2010-01-01

    Objectives The aim of this study was to investigate the bond strength of ceramic restorations luted using a self-adhesive resin cement (RelyX Unicem, 3M ESPE) under different dentin conditions. Material and Methods In the experimental groups, ceramic restorations were luted to bovine incisors with RelyX Unicem under the following conditions: [Dry dentin]: surface was dried using air stream for 15 s; [Moist dentin]: excess dentin moisture was removed with absorbent paper; [Bonding agent]: Clearfil SE Bond (Kuraray) self-etching adhesive system was previously applied to dentin. In the Control group, cementation was done using an etch-and-rinse adhesive (Excite DSC) and Variolink II resin cement (Ivoclar Vivadent). Photoactivation of the resin cements was performed with UltraLume LED 5 unit (Ultradent). The restorations (n=5 per group) were sectioned into beams and microtensile testing was carried out. Data were subjected to ANOVA and Tukey's test (padhesive failures was observed for the "bonding agent" and "dry dentin" groups. The "moist dentin" group presented predominantly cohesive failures within the luting material. The previous application of a self-etching adhesive showed no significant effect. Conclusions Only excess dentin moisture should be removed for the cementation of ceramic restorations with self-adhesive resin cements. PMID:20857001

  6. Luting glass ceramic restorations using a self-adhesive resin cement under different dentin conditions.

    Science.gov (United States)

    Guarda, Guilherme B; Gonçalves, Luciano S; Correr, Américo B; Moraes, Rafael R; Sinhoreti, Mário A C; Correr-Sobrinho, Lourenço

    2010-01-01

    The aim of this study was to investigate the bond strength of ceramic restorations luted using a self-adhesive resin cement (RelyX Unicem, 3M ESPE) under different dentin conditions. In the experimental groups, ceramic restorations were luted to bovine incisors with RelyX Unicem under the following conditions: [Dry dentin]: surface was dried using air stream for 15 s; [Moist dentin]: excess dentin moisture was removed with absorbent paper; [Bonding agent]: Clearfil SE Bond (Kuraray) self-etching adhesive system was previously applied to dentin. In the Control group, cementation was done using an etch-and-rinse adhesive (Excite DSC) and Variolink II resin cement (Ivoclar Vivadent). Photoactivation of the resin cements was performed with UltraLume LED 5 unit (Ultradent). The restorations (n=5 per group) were sectioned into beams and microtensile testing was carried out. Data were subjected to ANOVA and Tukey's test (padhesive failures was observed for the "bonding agent" and "dry dentin" groups. The "moist dentin" group presented predominantly cohesive failures within the luting material. The previous application of a self-etching adhesive showed no significant effect. Only excess dentin moisture should be removed for the cementation of ceramic restorations with self-adhesive resin cements.

  7. Post-bleaching application of an antioxidant on dentin bond strength of three dental adhesives

    Directory of Open Access Journals (Sweden)

    Maryam Khoroushi

    2012-01-01

    Conclusions: The findings suggest that bond strength of resin to bleached dentin may be affected with the adhesive system. Reduced SBS to bleached dentin can be amended by the use of SA as an antioxidizing agent. However, the amount of reversed bond strength subsequent to applying antioxidant might be related to the kind of dental adhesive.

  8. Shear bond strengths of three glass ionomer cements to enamel and dentine

    NARCIS (Netherlands)

    Carvalho, T.S.; van Amerongen, W.E.; de Gee, A.; Bönecker, M.; Sampaio, F.C.

    2011-01-01

    Objectives: The shear bond strength of three glass ionomer cements (GIC) to enamel and dentine was evaluated. Study Design: Sound permanent human molars (n=12) were grinded perpendicular to their axial axes, exposing smooth, flat enamel and dentine surfaces. The teeth were embedded in resin and

  9. Microtensile Bond Strength of Three Simplified Adhesive Systems to Caries-affected Dentin

    NARCIS (Netherlands)

    Scholtanus, Johannes; Purwanta, Kenny; Dogan, Nilgun; Kleverlaan, Cees J.; Feilzer, Albert J.

    Purpose: The purpose of the study was to determine the microtensile bond strength of three different simplified adhesive systems to caries-affected dentin. Materials and Methods: Fifteen extracted human molars with primary carious lesions were ground flat until dentin was exposed. Soft

  10. Shear bond strengths of glass-ionomer cements to sound and to prepared carious dentine.

    Science.gov (United States)

    Czarnecka, Beata; Deregowska-Nosowicz, Patricia; Limanowska-Shaw, Honorata; Nicholson, John W

    2007-05-01

    The aim of this study was determine whether bonding of glass-ionomer cements to non-carious dentine differed from that to carious dentine. Five commercial cements were used, namely Fuji IX GP, Fuji IX capsulated, Fuji IX Fast capsulated (all GC, Japan), Ketac-Molar and Ketac-Molar Aplicap (both 3M-ESPE, Germany). Following conditioning of the substrate with 10% poly (acrylic acid) for 10 s, sets of 10 samples of the cements were bonded to prepared teeth that had been removed for orthodontic reasons. The teeth used had either sound dentine or sclerotic dentine. Shear bond strengths were determined following 24 h storage. For the auto-mixed cements, shear bond strength to sound dentine was found not to differ statistically from shear bond strength to sclerotic dentine whereas for hand-mixed cements, shear bond to sound dentine was found to be higher than to carious dentine (to at least p < 0.05). This shows that the chemical effects arising from interactions of glass-ionomer cements with the mineral phase of the tooth are the most important in developing strong bonds, at least in the shorter term.

  11. Inhibition of dentin collagen degradation by hesperidin: an in situ study

    NARCIS (Netherlands)

    van Strijp, A.J.P.; Takatsuka, T.; Sono, R.; Iijima, Y.

    2015-01-01

    Dentine caries is a process of demineralization and subsequent degradation of the collagenous matrix. Host-derived proteolytic enzymes, such as matrix metalloproteinases (MMPs), play a role in this process of dentine collagen degradation. Hampering this degradation retards the caries process.

  12. A 3-day randomised clinical study investigating the efficacy of two toothpastes, designed to occlude dentine tubules, for the treatment of dentine hypersensitivity

    National Research Council Canada - National Science Library

    West, N; Newcombe, R G; Hughes, N; Mason, S; Maggio, B; Sufi, F; Claydon, N

    2013-01-01

    A product comparison study to compare the short term clinical efficacy of a strontium acetate/silica toothpaste with an arginine/calcium carbonate paste for pain reduction in dentine hypersensitivity...

  13. Accuracy of Cone-beam Computed Tomography in Measuring Dentin Thickness and Its Potential of Predicting the Remaining Dentin Thickness after Removing Fractured Instruments.

    Science.gov (United States)

    Xu, Jialei; He, Jingzhi; Yang, Qian; Huang, Dingming; Zhou, Xuedong; Peters, Ove A; Gao, Yuan

    2017-09-01

    The purpose of this study was to evaluate the accuracy of cone-beam computed tomographic (CBCT) to measure dentin thickness and its potential of predicting the remaining dentin thickness after the removal of fractured instrument fragments. Twenty-three human mandibular molars were selected, and 4-mm portions of #25/.06 taper K3 files (SybronEndo, Orange, CA) were fractured in mesial canals. The teeth were then scanned using a micro-computed tomographic (micro-CT) system and a CBCT unit. Dentin thickness was measured and compared between both micro-CT and CBCT images to study the accuracy of CBCT readings. Then, the process of removing the fragments was simulated in CBCT images using the MeVisLab package (MeVis Research, Bremen, Germany); the predicted minimal remaining dentin thickness after removal was measured in different layers using VGStudio MAX software (Volume Graphics, Heidelberg, Germany). Data were compared with the actual minimal remaining dentin thickness acquired from micro-CT images, which were scanned after removing fractured instruments using the microtrepan technique. The results were analyzed statistically using intraclass correlation coefficients (ICCs) and a forecasting regression model analysis. The ICC for the dentin thickness was 0.988. The forecasting regression model of CBCT imaging estimating dentin thickness was micro-CT imaging = 15.835 + 1.080*CBCT, R2 = 0.963. The ICC for the remaining dentin thickness was 0.975 (P < .001). The forecasting regression model of CBCT imaging forecasting remaining dentin thickness was micro-CT imaging = 147.999 + 0.879*adjusted CBCT, R2 = 0.906. The study showed that CBCT imaging could measure dentin thickness accurately. Furthermore, using CBCT images, it is reliable and feasible to forecast the remaining dentin thickness after simulated instrument removal. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  14. Immunohistochemical studies with a monoclonal antibody on the distribution of phosphophoryn in predentin and dentin.

    Science.gov (United States)

    Nakamura, O; Gohda, E; Ozawa, M; Senba, I; Miyazaki, H; Murakami, T; Daikuhara, Y

    1985-09-01

    A monoclonal antibody was raised against phosphophoryn, a unique noncollagenous phosphoprotein in dentin. Mouse myeloma NS-I cells were fused with spleen cells obtained from BALB/c mice immunized with phosphophoryn from fetal calf tooth germs. Mice inoculated with the hybridoma produced ascites fluid containing the antibody and this reacted only with a band of phosphophoryn transblotted from polyacrylamide gel. Immunohistochemical studies with the antibody showed that phosphophoryn was present in odontoblasts, odontoblastic processes and dentin, but not in the matrix of predentin, and that the phosphophoryn content of the dentin layer was high at and around the predentin-dentin junction and gradually decreased toward the enamel layer. The area corresponding to mantle dentin was not stained with the antibody.

  15. Vibrational analysis by Raman spectroscopy of the interface between dental adhesive resin and dentin.

    Science.gov (United States)

    Suzuki, M; Kato, H; Wakumoto, S

    1991-07-01

    The Raman microprobe technique was applied for analysis of the molecular components at the adhesive interface between 4-META/MMA-TBB resin and dentin. The Raman spectra showed that the 4-META molecules in monomer solution were mostly hydrolyzed into 4-MET molecules, which were then co-polymerized with MMA molecules to form resin and resin-reinforced dentin layers. On the basis of line analysis by the Raman microprobe, resin molecules were estimated to penetrate 6 microns into the dentin from the interface. Raman intensity studies indicated that the concentration of 4-MET molecular units in the resin-reinforced dentin was more than four times the concentration in the original monomer solution. This demonstrated the excellent infiltration ability of 4-MET monomer into dentin substrate in situ.

  16. Fracture aspects of resin-dentin bonding in non-trimming microtensile test.

    Science.gov (United States)

    Chen, K K; Shono, Y; Ogawa, T; Kozono, Y; Terashita, M

    2001-12-01

    Comparative studies on resin-dentin bond strength and failure mode were performed between the conventional tensile test and the microtensile test with non-trimming small specimens, 1 x 1 mm in cross-section, for two brands of dentin bonding systems. The fracture surface of the conventional large specimen showed a catastrophic cohesive failure in dentin at its center and a lesser adhesive failure, suggesting that the whole failure was due to the development of some major cracks. The non-trimming microtensile test showed significantly larger average bond strength with markedly larger standard deviation and significantly larger fraction of adhesive failure than the conventional test. Some small specimens were extremely strong and some were weak according to the heterogeneous distribution of tight bonding and defective or deficient bonding over the whole dentin surface. These results suggest that the non-trimming microtensile test may potentially provide more realistic aspects of resin-dentin bonding than the conventional bulk specimen.

  17. Comparison of human dental follicle cells and human periodontal ligament cells for dentin tissue regeneration.

    Science.gov (United States)

    Tian, Ye; Bai, Ding; Guo, Weihua; Li, Jie; Zeng, Jin; Yang, Longqiang; Jiang, Zongting; Feng, Lian; Yu, Mei; Tian, Weidong

    2015-05-01

    To compare the odontogenic potential of human dental follicle cells (DFCs) and periodontal ligament cells (PDLCs). In vitro and in vivo characterization studies of DFCs and PDLCs were performed comparatively. DFCs and PDLCs were subcutaneously implanted into the dorsum of mice for 8 weeks after combined with treated dentin matrix scaffolds respectively. Proteomic analysis identified 32 differentially expressed proteins in DFCs and PDLCs. Examination of the harvested grafts showed PDLCs could form the dentin-like tissues as DFCs did. However, the structure of dentin tissues generated by DFCs was more complete. PDLCs could contribute to regenerate dentin-like tissues in the inductive microenvironment of treated dentin matrix. DFCs presented more remarkable dentinogenic capability than PDLCs did.

  18. Dentin matrix degradation by host Matrix Metalloproteinases: inhibition and clinical perspectives towards regeneration.

    Directory of Open Access Journals (Sweden)

    Catherine eChaussain

    2013-11-01

    Full Text Available Bacterial enzymes have long been considered solely accountable for the degradation of the dentin matrix during the carious process. However, the emerging literature suggests that host-derived enzymes, and in particular the matrix metalloproteinases (MMPs contained in dentin and saliva can play a major role in this process by their ability to degrade the dentin matrix from within. These findings are important since they open new therapeutic options for caries prevention and treatment. The possibility of using MMP inhibitors to interfere with dentin caries progression is discussed. Furthermore, the potential release of bioactive peptides by the enzymatic cleavage of dentin matrix proteins by MMPs during the carious process is discussed. These peptides, once identified, may constitute promising therapeutical tools for tooth and bone regeneration.

  19. In vitro dentine remineralization with a potential salivary phosphoprotein homologue.

    Science.gov (United States)

    Romero, Maria Jacinta Rosario H; Nakashima, Syozi; Nikaido, Toru; Sadr, Alireza; Tagami, Junji

    2016-08-01

    Advantages of introducing a salivary phosphoprotein homologue under standardized in vitro conditions to simulate the mineral-stabilizing properties of saliva have been proposed. This study longitudinally investigates the effects of casein, incorporated as a potential salivary phosphoprotein homologue in artificial saliva (AS) solutions with/without fluoride (F) on in vitro dentine lesion remineralization. Thin sections of bovine root dentine were demineralized and allocated randomly into 6 groups (n=18) having equivalent mineral loss (ΔZ) after transverse microradiography (TMR). The specimens were remineralized using AS solutions containing casein 0μg/ml, F 0ppm (C0-F0); casein 0μg/ml, F 1ppm (C0-F1); casein 10μg/ml, F 0ppm (C10-F0); casein 10μg/ml, F 1ppm (C10-F1); casein 100μg/ml, F 0ppm (C100-F0) or casein 100μg/ml, F 1ppm (C100-F1) for 28days with TMR taken every 7 days. Surface mineral precipitation, evident in group C0-F1, was apparently inhibited in groups with casein incorporation. Repeated measures ANOVA with Bonferroni correction revealed higher ΔZ for non-F and non-casein groups than for their counterparts (p<0.001). Subsequent multiple comparisons showed that mineral gain was higher (p<0.001) with 10μg/ml casein than with 100μg/ml when F was present in the earlier stages of remineralization, with both groups achieving almost complete remineralization after 28 days. Casein is a potential salivary phosphoprotein homologue that could be employed for in vitro dentine remineralization studies. Concentration related effects may be clinically significant and thus must be further examined. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Pulp response and cytotoxicity evaluation of 2 dentin bonding agents.

    Science.gov (United States)

    Demarco, F F; Tarquinio, S B; Jaeger, M M; de Araújo, V C; Matson, E

    2001-03-01

    This study evaluated the biocompatibility of two dentin bonding agents (Clearfil Liner Bond 2 and Scotchbond Multi-Purpose) applied in human dental pulps and cell cultures. In vivo: Twenty human third molars that were scheduled for extraction were used. After cavity preparation, pulp exposure was achieved with a carbide bur. Hemorrhage control was obtained with saline solution. In 16 teeth, adhesive pulp capping was performed and the cavities were sealed with resin composite. In the control group (n = 4), pulps were capped with Ca(OH)2 and the cavities were sealed with IRM. Teeth were extracted 30 or 90 days following treatment and prepared for histological examination and bacterial detection. In vitro: materials were applied in Petri dishes, where NIH-3T3 cells were plated. The cells were counted 2, 4, and 6 days after plating to obtain the growth curves and to determine cell viability. All data were submitted to statistical analysis. In vivo: Dentin bridge formation was seen in all teeth capped with Ca(OH)2, without an inflammatory response. Mild inflammatory responses and dentin bridge formation after 90 days were observed in 50% of specimens treated with Liner Bond 2. Pulps treated with Scotchbond Multi-Purpose presented mild to severe inflammatory response, and no mineralized tissue formation was detected. Bacteria were not disclosed in any specimen. In vitro: The cytotoxicity was similar between the two bonding agents, and both had statistically higher cytotoxic effects (P cytotoxic effects than both adhesive systems; however, pulp healing was also observed under Liner Bond 2.

  1. Bonding of restorative materials to dentin with various luting agents.

    Science.gov (United States)

    Peutzfeldt, A; Sahafi, A; Flury, S

    2011-01-01

    The aim was to compare eight types of luting agents when used to bond six indirect, laboratory restorative materials to dentin. Cylinders of the six restorative materials (Esteticor Avenir [gold alloy], Tritan [titanium], NobelRondo [feldspathic porcelain], Finesse All-Ceramic [leucite-glass ceramic], Lava [zirconia], and Sinfony [resin composite]) were ground and air-abraded. Cylinders of feldspathic porcelain and glass ceramic were additionally etched with hydrofluoric acid and were silane-treated. The cylinders were luted to ground human dentin with eight luting agents (DeTrey Zinc [zinc phosphate cement], Fuji I [conventional glass ionomer cement], Fuji Plus [resin-modified glass ionomer cement], Variolink II [conventional etch-and-rinse resin cement], Panavia F2.0 and Multilink [self-etch resin cements], and RelyX Unicem Aplicap and Maxcem [self-adhesive resin cements]). After water storage at 37°C for one week, the shear bond strength of the specimens (n=8/group) was measured, and the fracture mode was stereomicroscopically examined. Bond strength data were analyzed with two-factorial analysis of variance (ANOVA) followed by Newman-Keuls' Multiple Range Test (α=0.05). Both the restorative material and the luting agent had a significant effect on bond strength, and significant interaction was noted between the two variables. Zinc phosphate cement and glass ionomer cements produced the lowest bond strengths, whereas the highest bond strengths were found with the two self-etch and one of the self-adhesive resin cements. Generally, the fracture mode varied markedly with the restorative material. The luting agents had a bigger influence on bond strength between restorative materials and dentin than was seen with the restorative material.

  2. Immediate bonding effectiveness of contemporary composite cements to dentin.

    Science.gov (United States)

    Sarr, Mouhamed; Mine, Atsushi; De Munck, Jan; Cardoso, Marcio Vivan; Kane, Abdoul Wakhabe; Vreven, José; Van Meerbeek, Bart; Van Landuyt, Kirsten L

    2010-10-01

    The objective of this study was to compare the one-week bonding effectiveness of nine contemporary composite cements used to lute ceramic to dentin and to determine an appropriate processing method for pretesting failures. The microtensile bond strengths (µTBS) of different luting agents including five self-adhesive cements (Unicem, 3 M ESPE; Maxcem, Kerr; Monocem, Shofu; G-Cem, GC; and Multilink Sprint, Ivoclar-Vivadent), two self-etch cements (Panavia F2.0 and Clearfil Esthetic Cement, Kuraray), and two etch-and-rinse cements (Calibra, Dentsply, and Variolink II, Ivoclar-Vivadent) were measured using a standardized protocol. As control, a two-step self-etch adhesive combined with a restorative composite (Clearfil SE+Clearfil APX, Kuraray) were included as luting material. Depending on the processing of the pretesting failures, two groups of cements could be distinguished: (1) those with low bond strength and many pretesting failures and (2) those with relatively high bond strength and few pretesting failures. Nevertheless, the control luting procedure involving a self-etch adhesive combined with a restorative composite presented with a significantly higher µTBS. The µTBS was clearly product-dependent rather than being dependent on the actual adhesive approach. Fracture analysis indicated that failure usually occurred at the dentin-cement interface especially for the cements with low bond strength and many pretesting failures. Depending on the cement system, an adequate immediate ceramic-to-dentin bond strength can be obtained, even with self-adhesive cements that do not use a separate dental adhesive. Yet, the self-etch adhesive Clearfil SE combined with the restorative composite revealed a superior bonding performance and should therefore be preferred in clinical situations where the restoration transmits light sufficiently.

  3. Immediate bonding properties of universal adhesives to dentine.

    Science.gov (United States)

    Muñoz, Miguel Angel; Luque, Issis; Hass, Viviane; Reis, Alessandra; Loguercio, Alessandro Dourado; Bombarda, Nara Hellen Campanha

    2013-05-01

    To evaluate the dentine microtensile bond strength (μTBS), nanoleakage (NL), degree of conversion (DC) within the hybrid layer for etch-and-rinse and self-etch strategies of universal simplified adhesive systems. forty caries free extracted third molars were divided into 8 groups for μTBS (n=5), according to the adhesive and etching strategy: Clearfil SE Bond [CSE] and Adper Single Bond 2 [SB], as controls; Peak Universal Adhesive System, self-etch [PkSe] and etch-and-rinse [PkEr]; Scotchbond Universal Adhesive, self-etch [ScSe] and etch-and-rinse [ScEr]; All Bond Universal, self-etch [AlSe] and etch-and-rinse [AlEr]. After restorations were constructed, specimens were stored in water (37°C/24h) and then resin-dentine sticks were prepared (0.8mm(2)). The sticks were tested under tension at 0.5mm/min. Some sticks from each tooth group were used for DC determination by micro-Raman spectroscopy or nanoleakage evaluation (NL). The pH for each solution was evaluated using a pH metre. Data were analyzed with one-way ANOVA and Tukey's test (α=0.05). For μTBS, only PkSe and PkEr were similar to the respective control groups (p>0.05). AlSe showed the lowest μTBS mean (puniversal adhesives was shown to be material-dependent. The results indicate that this new category of universal adhesives used on dentine as either etch-and-rinse or self-etch strategies were inferior as regards at least one of the properties evaluated (μTBS, NL and DC) in comparison with the control adhesives (CSE for self-etch and SB for etch-and-rinse). Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Defying ageing: An expectation for dentine bonding with universal adhesives?

    Science.gov (United States)

    Zhang, Zheng-yi; Tian, Fu-cong; Niu, Li-na; Ochala, Kirsten; Chen, Chen; Fu, Bai-ping; Wang, Xiao-yan; Pashley, David H; Tay, Franklin R

    2016-02-01

    The present study evaluated the long-term dentine bonding effectiveness of five universal adhesives in etch-and-rinse or self-etch mode after 12 months of water-ageing. The adhesives evaluated included All-Bond Universal, Clearfil Universal Bond, Futurabond U Prime&Bond Elect and Scotchbond Universal. Microtensile bond strength and transmission electron microscopy of the resin-dentine interfaces created in human coronal dentine were examined after 24h or 12 months. Microtensile bond strength were significantly affected by bonding strategy (etch-and-rinse vs self-etch) and ageing (24h vs 12 months). All subgroups showed significantly decreased bond strength after ageing except for Prime&Bond Elect and Scotchbond Universal used in self-etch mode. All five adhesives employed in etch-and-rinse mode exhibited ultrastructural features characteristic of collagen degradation and resin hydrolysis. A previously-unobserved inside-out collagen degradation pattern was identified in hybrid layers created by 10-MDP containing adhesives (All-Bond Universal, Scotchbond Universal and Clearfil Universal Bond) in the etch-and-rinse mode, producing partially degraded collagen fibrils with intact periphery and a hollow core. In the self-etch mode, all adhesives except for Prime&Bond Elect exhibited degradation of the collagen fibrils along the thin hybrid layers. The three 10-MDP containing universal adhesives did not protect surface collagen fibrils from degradation when bonding was performed in the self-etch mode. Despite the adjunctive conclusion that bonds created by universal adhesives in the self-etch bonding mode are more resistant to decline in bond strength when compared with those bonds created using the etch-and-rinse mode, bonds created by universal adhesives are generally incapable of defying ageing. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Effect of Dentin Pretreatment on Bond Strength Stability of Self-etching and Etch-and-Rinse Adhesives to Intracoronally Bleached Dentin.

    Science.gov (United States)

    Souza, Ilzes Marianne Borges de; Araújo, Camila Silva; Soares, Carlos José; Faria-E-Silva, André Luis

    To evaluate the effect of chlorhexidine or glutaraldehyde pretreatment on the bonding stability of selfetching and etch-and-rinse adhesives to bleached dentin. The occlusal surface of 80 third molars was abraded to expose a flat mid-dentin surface, which was then subjected to a bleaching procedure using 20% hydrogen peroxide and sodium perborate for 14 days. Afterwards, the specimens were kept in distilled water, followed by application of either a three-step etchand- rinse (Adper Scotchbond Multi-Purpose Plus, SBMP) or a two-step self-etching (Clearfil SE Bond, CSE) adhesive system. For each approach, the bleached dentin was treated with chlorhexidine or glutaraldehyde, or left untreated, prior to the adhesive procedure. Unbleached dentin was used as a control. Composite cylinders were built up over the adhesive-covered dentin followed by parallel sectioning of specimens to obtain 1-mm slices. The slices were trimmed to obtain hourglass-shaped specimens with approximately 1.0 mm2 of bonding interface. Half of the specimens were subjected to microtensile bond strength (μTBS) testing after 24 h, while the other half were stored in distilled water for 3 months prior to the μTBS test. The mode of failure was analyzed using optical microscopy. For the SBMP protocol, the highest μTBS was achieved with glutaraldehyde-treated dentin, and the same μTBS values were maintained after 3 months of storage. For the CSE protocol, the highest μTBS was obtained with chlorhexidine-treated dentin. Glutaraldehyde and chlorhexidine pretreatment should be considered to improve the μTBS of adhesives to bleached dentin, while the pretreatment effect was adhesive dependent.

  6. Tomographic Evaluation of Reparative Dentin Formation after Direct Pulp Capping with Ca(OH)2, MTA, Biodentine, and Dentin Bonding System in Human Teeth.

    Science.gov (United States)

    Nowicka, Alicja; Wilk, Grażyna; Lipski, Mariusz; Kołecki, Janusz; Buczkowska-Radlińska, Jadwiga

    2015-08-01

    New materials can increase the efficiency of pulp capping through the formation of a complete reparative dentin bridge with no toxic effects. The present study involved tomographic evaluations of reparative dentin bridge formation after direct pulp capping with calcium hydroxide, mineral trioxide aggregate (MTA), Biodentine (Septodont, Saint Maur des Fossés, France), and Single Bond Universal (3M ESPE, Seefeld, Germany) in human teeth. Forty-four caries-free, intact, human third molars scheduled for extraction were subjected to mechanical pulp exposure and assigned to 1 of 4 experimental groups depending on the pulp capping agent used: calcium hydroxide, MTA, Biodentine, or Single Bond Universal. After 6 weeks, the teeth were extracted and processed for cone-beam computed tomographic imaging and histologic examination. Tomographic data, including the density and volume of formed reparative dentin bridges, were evaluated using a scoring system. The reparative dentin formed in the calcium hydroxide, MTA, and Biodentine groups was significantly superior to that formed in the Single Bond Universal group in terms of thickness and volume. The dentin bridges in the Biodentine group showed the highest average and maximum volumes. The mean density of dentin bridges was the highest in the MTA group and the lowest in the Single Bond Universal group. The volume of reparative dentin bridges formed after direct pulp capping is dependent on the material used. Biodentine and MTA resulted in the formation of bridges with a significantly higher average volume compared with Single Bond Universal, and cone-beam computed tomographic imaging allowed for the identification of the location of dentin bridges. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  7. [The dentinal smear layer. Characteristics and interactions. 2].

    Science.gov (United States)

    Negri, P L; Eramo, S; Lotito, M; De Pino, C

    1991-03-15

    The Authors, after the presentation (in the first part of the Dossier) of a large literature review about the physical, chemical and clinical characteristics of formation, interaction, remotion of "smear layer" during cavity preparation in hard tooth tissue, describe the results of a scanning microelectronic research about the action as cleanser (for the dentinal cavity wall) of the CK101 (Caridex) versus wather, Tubulicid and phosphoric acid. The experimental results obtained "in vitro" show that the substance has relative action, without removing the tubular portion of "smear layer".

  8. DAMAGE QUANTIFICATION OF DENTINE SURFACE AFTER BLASTING WITH SODIUM BICARBONATE

    OpenAIRE

    MARCELO SOUZA MAGALHAES BASTOS

    2005-01-01

    Este trabalho apresenta os resultados da quantificação do dano em superfícies dentinárias de molares humanos após jateamento com bicarbonato de sódio. Após a seleção e preparação das amostras, as mesmas foram divididas em dois grupos experimentais (Grupo Controle e Grupo de Jateamento). Inicialmente, mediu-se a rugosidade e dureza local (microdureza) do Grupo Controle, adotadas como valores padrão. Em seqüência, as amostras do Grupo de Jateamento fora...

  9. Enamel and dentin as multi-scale bio-composites.

    Science.gov (United States)

    Bar-On, Benny; Daniel Wagner, H

    2012-08-01

    Dentin and enamel are viewed here as multi-scale composites comprising a staggered micro-structure made of stiff platelets embedded in a more compliant matrix, and further assembled into macroscopic composite-like structures. Mechanical models are formulated for both tissues and their effective moduli are evaluated analytically. The resulting predictions are in very good agreement with Finite Elements (FE) simulations and experimental data from the literature. The models developed in this study demonstrate the possibility, in certain cases, to generate special mechanical effects linked to the structural complexity of these tissues. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Hipótesis actuales relacionadas con la sensibilidad dentinal

    OpenAIRE

    Andrés Pérez Ruiz; Manuel Cabrera Duranza; Pablo E. Santos Rodríguez

    1999-01-01

    Se hace una revisión sobre las hipótesis actuales concernientes a la sensibilidad dentinal, centrando el análisis en las teorías acerca de la presencia de nervios en la dentina, la transmisión del impulso nervioso mediante el odontoblasto y el movimiento de fluidos dentro de la dentina. Por ser la explicación de la sensibilidad de la dentina uno de los más complejos problemas de la fisiología y la histología del diente, se exponen los hechos morfológicos y funcionales que apoyan la validez de...

  11. Dentin-enamel adhesives in pediatric dentistry: an update.

    Science.gov (United States)

    García-Godoy, Franklin; Donly, Kevin J

    2015-01-01

    Adhesives and composite technology have made composite resins and polyacid-modified resin-based composites (compomers) very popular as materials to restore primary and permanent anterior and posterior teeth. More conservative preparations can be performed that maintain more tooth structure due to the adhesive properties of the adhesives used with composites and compomers. Meticulous care in the placement of adhesives and, subsequently, resin-based composites and compomers is necessary to produce long-term satisfactory results. The purpose of this paper is to update the current status in regards to dentin-enamel adhesives in primary teeth.

  12. Bonding effectiveness of adhesive luting agents to enamel and dentin.

    Science.gov (United States)

    Hikita, K; Van Meerbeek, B; De Munck, J; Ikeda, T; Van Landuyt, K; Maida, T; Lambrechts, P; Peumans, M

    2007-01-01

    The bonding effectiveness of five adhesive luting agents to enamel and dentin using different application procedures was determined using a micro-tensile bond strength protocol (microTBS). Enamel/dentin surfaces of human third molars were flattened using a high-speed diamond bur. Composite resin blocks (Paradigm, 3M ESPE) were luted using either Linkmax (LM; GC), Nexus 2 (NX; Kerr), Panavia F (PN; Kuraray), RelyX Unicem (UN; 3M ESPE) or Variolink II (VL; Ivoclar-Vivadent), strictly following manufacturers' instructions. For some luting agents, modified application procedures were also tested, resulting in four other experimental groups: Prompt L-Pop+RelyX Unicem (PLP+UN; 3M ESPE), Scotchbond Etchant+RelyX Unicem (SE+UN; 3M ESPE), Optibond Solo Plus Activator+Nexus 2 (ACT+NX; Kerr) and K-Etchant gel+Panavia-F (KE+P; Kuraray). The experimental groups were classified according to the adhesive approach in self-adhesive (UN), etch-and-rinse (ACT+NX, NX, KE+P, SE+UN and VL when bonded to enamel) and self-etch adhesive luting agents (LM, PLP+UN, PN and VL when bonded to dentin). The specimens were stored for 24h in distilled water at 37 degrees C prior to microTBS testing. The Kruskal-Wallis test was used to determine pairwise statistical differences (padhesive separately and an insufficiently light-cured luting agent. Following a correct application procedure, the etch-and-rinse, self-etch and self-adhesive luting agents are equally effective in bonding to enamel and dentin. Several factors negatively influenced bond strength such as bonding RelyX Unicem to enamel without prior phosphoric acid etching; no separate light-curing of a light-polymerizable adhesive prior to cementation, use of a light-polymerizing adhesive converted into a dual-polymerizing adhesive, and use of a dual-cure luting agent with a low auto-polymerizable potential.

  13. Economic aspects of the detection of occlusal dentine caries

    DEFF Research Database (Denmark)

    Norlund, Anders; Axelsson, Susanna; Dahlen, Gunnar

    2009-01-01

    and in vivo studies of medium and high quality. The direct costs for examinations and restorative care were extracted from the costs of the Public Dental Service in Sweden (2006). RESULTS: The diagnostic costs per true-positive finding were dependent on the occurrence of occlusal caries and increased......OBJECTIVE: To evaluate the cost of true-positive occlusal dentine caries detection in permanent molars assessed by: (I) visual-tactile examination, (II) visual-tactile examination combined with bitewing radiographs, and (III) selective radiographic examination of patients with lesions detected...

  14. In Vitro Study of Dentin Hypersensitivity Treated by 980-nm Diode Laser

    Science.gov (United States)

    Liu, Ying; Gao, Jie; Gao, Yan; XU, Shuaimei; Zhan, Xueling; Wu, Buling

    2013-01-01

    Introduction: To investigate the ultrastructural changes of dentin irradiated with 980-nm diode laser under different parameters and to observe the morphological alterations of odontoblasts and pulp tissue to determine the safety parameters of 980-nm diode laser in the treatment of dentin hypersensitivity (DH). Methods: Twenty extracted human third molars were selected to prepare dentin discs. Each dentin disc was divided into four areas and was irradiated by 980-nm diode laser under different parameters: Group A: control group, 0 J/cm2; Group B: 2 W/CW (continuous mode), 166 J/cm2; Group C: 3W/CW, 250 J/cm2; and Group D: 4W/CW, 333 J/cm2. Ten additional extracted human third molars were selected to prepare dentin discs. Each dentin disc was divided into two areas and was irradiated by 980-nm diode laser: Group E: control group, 0 J/cm2; and Group F: 2.0 W/CW, 166 J/cm2. The morphological alterations of the dentin surfaces and odontoblasts were examined with scanning electron microscopy (SEM), and the morphological alterations of the dental pulp tissue irradiated by laser were observed with an upright microscope. Results: The study demonstrated that dentinal tubules can be entirely blocked after irradiation by 980-nm diode laser, regardless of the parameter setting. Diode laser with settings of 2.0 W and 980-nm sealed exposed dentin tubules effectively, and no significant morphological alterations of the pulp and odontoblasts were observed after irradiation. Conclusions: Irradiation with 980-nm diode laser could be effective for routine clinical treatment of DH, and 2.0W/CW (166 J/cm2) was a suitable energy parameter due to its rapid sealing of the exposed dentin tubules and its safety to the odontoblasts and pulp tissue. PMID:25606318

  15. Morphological/chemical imaging of demineralized dentin layer in its natural, wet state.

    Science.gov (United States)

    Wang, Yong; Yao, Xiaomei

    2010-05-01

    Measuring the structure, composition or suitability for bonding of the acid-etched dentin substrate, especially in its hydrated state, has been a formidable problem. The purpose of this study was to determine the morphological and structural profiles of the dentin demineralized layer measured in its natural wet state using environmental scanning electron microscopy (ESEM) and micro-Raman imaging. The occlusal 1/3 of the crown was removed from nine extracted, unerupted human third molars. Dentin surfaces were abraded with 600-grit SiC sandpaper under water to create smear layers. The prepared dentin surfaces were randomly selected for treatment with the self-etching agent (Adper Prompt L-Pop) or the total-etching agent 35% H(3)PO(4) gel (with/without agitation). Micro-Raman spectra and imaging were acquired at 1-1.5microm spatial resolution at positions perpendicular to the treated surfaces; since this technique is non-destructive, the same specimens were also imaged with ESEM. Specimens were kept wet throughout spectral acquisition and ESEM observations. ESEM could be used to reveal demineralized layers in acid-etched dentin, but the resolution was low and no collagen fibrils were disclosed. The detailed chemical maps/profiles of demineralized dentin layers under wet conditions could be obtained using Raman imaging. It was shown that the mineral existed in the superficial layer of all etched dentin covered with smear layers. The mineral was much easier to be removed underneath the superficial layer. The depth, degree, and profile of dentin demineralization were dependent on the types of acids (self-etching vs. total etching) and application procedures (with vs. without agitation). Most current adhesives are applied using wet bonding techniques in which the dentin is kept fully hydrated throughout the bonding. Our ability to fully characterize the hydrated, etched dentin substrates is very important for understanding bonding under in vivo conditions. 2010 Academy of

  16. Attachment and growth of dental pulp stem cells on dentin in presence of extra calcium.

    Science.gov (United States)

    Özdal-Kurt, F; Şen, B H; Tuğlu, I; Vatansever, S; Türk, B T; Deliloğlu-Gürhan, I

    2016-08-01

    We aimed to differentiate dental pulp stem cells (DPSC) to odontoblast-like cells (ODPSC) and to investigate their attachment and growth on dentin in the presence of extra calcium by colorimetric assay and scanning electron microscopy (SEM). After isolation of DPSC, they were differentiated to ODPSC. Standard dentin discs from human molar teeth were prepared. While the dentin discs in Group 1 did not receive any extra treatment, the discs in Group 2 were treated with acidic calcium phosphate precipitation (CPP) solution. In Group 3, the discs were suspended in phosphate buffered saline containing calcium. DPSC or ODPSC (3×10(4) cells/mL) were seeded on all discs and incubated for 7, 14 or 21 days. Attachment and growth of 7-day cell cultures on extra dentin samples were examined by SEM. MTT assay showed that number of cells on dentin surfaces was increased by time periods regardless of type of treatment and cells (p0.05), the number of ODPSC was higher than DPSC in 21-day samples (p=0.039). MTT assay showed that number of cells on dentin surfaces was increased by time periods regardless of type of treatment and cells (pdentin surfaces always had lower number of cells; being significant for only CPP-treated surfaces (ptypes of cells demonstrated good attachment and proliferation on dentin surfaces regardless of type of dentin treatment. Because the nature of dentin surface itself showed good adhesive characteristics with ODPSC and DPSC, additional calcium treatment of dentin surfaces may not be necessary. Copyright © 2016. Published by Elsevier Ltd.

  17. EDTA conditioning of dentine promotes adhesion, migration and differentiation of dental pulp stem cells.

    Science.gov (United States)

    Galler, K M; Widbiller, M; Buchalla, W; Eidt, A; Hiller, K-A; Hoffer, P C; Schmalz, G

    2016-06-01

    To evaluate the effect of dentine conditioning on migration, adhesion and differentiation of dental pulp stem cells. Dentine discs prepared from extracted human molars were pre-treated with EDTA (10%), NaOCl (5.25%) or H2 O. Migration of dental pulp stem cells towards pre-treated dentine after 24 and 48 h was assessed in a modified Boyden chamber assay. Cell adhesion was evaluated indirectly by measuring cell viability. Expression of mineralization-associated genes (COL1A1, ALP, BSP, DSPP, RUNX2) in cells cultured on pre-treated dentine for 7 days was determined by RT-qPCR. Nonparametric statistical analysis was performed for cell migration and cell viability data to compare different groups and time-points (Mann-Whitney U-test, α = 0.05). Treatment of dentine with H2 O or EDTA allowed for cell attachment, which was prohibited by NaOCl with statistical significance (P = 0.000). Furthermore, EDTA conditioning induced cell migration towards dentine. The expression of mineralization-associated genes was increased in dental pulp cells cultured on dentine after EDTA conditioning compared to H2 O-pre-treated dentine discs. EDTA conditioning of dentine promoted the adhesion, migration and differentiation of dental pulp stem cells towards or onto dentine. A pre-treatment with EDTA as the final step of an irrigation protocol for regenerative endodontic procedures has the potential to act favourably on new tissue formation within the root canal. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  18. Luting glass ceramic restorations using a self-adhesive resin cement under different dentin conditions

    Directory of Open Access Journals (Sweden)

    Guilherme B Guarda

    2010-06-01

    Full Text Available OBJECTIVES: The aim of this study was to investigate the bond strength of ceramic restorations luted using a self-adhesive resin cement (RelyX Unicem, 3M ESPE under different dentin conditions. MATERIAL AND METHODS: In the experimental groups, ceramic restorations were luted to bovine incisors with RelyX Unicem under the following conditions: [Dry dentin]: surface was dried using air stream for 15 s; [Moist dentin]: excess dentin moisture was removed with absorbent paper; [Bonding agent]: Clearfil SE Bond (Kuraray self-etching adhesive system was previously applied to dentin. In the Control group, cementation was done using an etch-and-rinse adhesive (Excite DSC and Variolink II resin cement (Ivoclar Vivadent. Photoactivation of the resin cements was performed with UltraLume LED 5 unit (Ultradent. The restorations (n=5 per group were sectioned into beams and microtensile testing was carried out. Data were subjected to ANOVA and Tukey's test (p<0.05. Failure modes were classifed under Scanning Electron Microscopic (SEM (x120 magnifcation. RESULTS: The bond strength was dependent on the moisture status of the dentin. Bond strength in the "dry dentin group" was signifcantly lower than that of all other groups, which showed similar results. A predominance of mixed failures was detected for the control group, while a predominance of adhesive failures was observed for the "bonding agent" and "dry dentin" groups. The "moist dentin" group presented predominantly cohesive failures within the luting material. The previous application of a self-etching adhesive showed no signifcant effect. CONCLUSIONS: Only excess dentin moisture should be removed for the cementation of ceramic restorations with self-adhesive resin cements.

  19. Glutaraldehyde-induced remineralization improves the mechanical properties and biostability of dentin collagen

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chaoqun; Mao, Caiyun; Sun, Jian; Chen, Yi; Wang, Wei [Department of Stomatology, The First Affiliated Hospital, College of Medicine, Zhejiang University (China); Pan, Haihua; Tang, Ruikang [Centre for Biopathways and Biomaterials, Department of Chemistry, Zhejiang University (China); Gu, Xinhua [Department of Stomatology, The First Affiliated Hospital, College of Medicine, Zhejiang University (China)

    2016-10-01

    The purpose of this study was to induce a biomimetic remineralization process by using glutaraldehyde (GA) to reconstruct the mechanical properties and biostability of demineralized collagen. Demineralized dentin disks (35% phosphoric acid, 10 s) were pretreated with a 5% GA solution for 3 min and then cultivated in a calcium phosphate remineralization solution. The remineralization kinetics and superstructure of the remineralization layer were evaluated by Raman spectroscopy, transmission electron microscopy, scanning electron microscopy and nanoindentation tests. The biostability was examined by enzymatic degradation experiments. A significant difference was found in dentin remineralization process between dentin with and without GA pretreating. GA showed a specific affinity to dentin collagen resulting in the formation of a cross-linking superstructure. GA pretreating could remarkably shorten remineralization time from 7 days to 2 days. The GA-induced remineralized collagen fibrils were well encapsulated by newly formed hydroxyapatite mineral nanocrystals. With the nano-hydroxyapatite coating, both the mechanical properties (elastic modulus and hardness) and the biostability against enzymatic degradation of the collagen were significantly enhanced, matching those of natural dentin. The results indicated that GA cross-linking of dentin collagen could promote dentin biomimetic remineralization, resulting in an improved mechanical properties and biostability. It may provide a promising tissue-engineering technology for dentin repair. - Highlights: • GA cross-linking can promote the remineralization kinetics of dentin collagen. • GA-induced remineralization can reshape the demineralized dentin collagen layer. • The GA-induced remineralization enhances the degradation resistance of collagen. • GA-induced remineralization provides a new approach to improve bonding durability.

  20. Bio-modification approach for novel dentine caries management by Galla chinesis extract and microbial transglutaminase

    Directory of Open Access Journals (Sweden)

    Meng Deng

    2012-01-01

    Full Text Available Introduction: Dental caries still remains one of the most prevalent diseases worldwide. Unlike enamel caries which can be restored mainly by modulating mineral balance, the dentine caries are characterized with irreversible proteolytic disintegration of organic matrices, highlighting an urgent need to seek novel management strategies. Bio-modification of dentine matrix has been proposed as a novel and alternative approach to enhancing its biochemical and biomechanical properties. The resultant chemical stability and mechanic durability are specifically desirable for prevention and restoration of dentine caries. However, conventional cross linking agents, e.g. glutaraldehyde, formaldehyde,are unsuitable for clinical use due to marked cytotoxicity or instability over time. The Hypothesis: Previous studies revealed that Galla chinesis extract (GCE could inhibit cariogenic microbes and positively modulate enamel de/remineralization balance, and the mechanism was directed to the polyphenols-organic matrix interaction involving hydrogen, covalent, ionic bonding and hydrophobic processes. Microbial transglutaminase (mTGase could induce crosslinks between peptide chains and improve functional properties of food proteins by catalyzing an acyl transfer reaction through ε - (γ-glutamyl lysine (GL bonds. Given the high organic content in dentine and universal reaction nature of GCE and mTGase, we put forward a hypothesis that these two natural products may serve as novel biocompatible bio-modifiers to improve biochemical and biomechanical properties of dentine matrices. Evaluation of the Hypothesis: The validation of our hypothesis will provide profound insights updating current therapeutic strategies against dentine caries, and pioneer novel approaches for biocompatible bio-modification of dentine matrices. Specifically, GCE and mTGase can be integrated into the root canal irrigating and dentine boding procedures, where they may generate beneficial

  1. Análisis de las causas de muerte de los primeros habitantes de la ciudad de La Plata (1887)

    National Research Council Canada - National Science Library

    Flores, Olga B; Iglesias, María T

    2003-01-01

    ...". Nuestra investigación se basó fundamentalmente en el análisis de las actas de defunción del Archivo del Cementerio Municipal con el fin de indagar sobre la incidencia diferencial o no de las causas de muerte...

  2. Utilização da imprensa escrita na qualificação das causas externas de morte

    Directory of Open Access Journals (Sweden)

    Lenice de Castro Mendes Villela

    2012-08-01

    Full Text Available OBJETIVO: Complementar a informação sobre a causa básica de morte em óbitos por causas externas com uso de notícias veiculadas em jornais. MÉTODOS: Estudo de investigação de 153 óbitos por causas externas ocorridas em residentes de Belo Horizonte, MG, em 2008. Construiu-se o banco de dados denominado imprensa, com informações de jornais de grande circulação nacional e estadual, o qual foi relacionado ao banco de dados do Sistema de Informações de Mortalidade. Os dados foram analisados nos programas EpiInfo e o Link-plus. A concordância dos resultados foi avaliada pelo coeficiente kappa. RESULTADOS: Foram localizadas 1.530 notícias sobre acidentes e violências, 201 das quais foram pareadas às declarações de óbito do banco do Sistema de Informações de Mortalidade e 153 notícias eram de residentes de Belo Horizonte. As principais causas de morte identificadas nos bancos foram agressões e acidentes de transporte. No banco imprensa, agressões e acidentes de transporte corresponderam a 86,3%, outros acidentes 7,8%, eventos de intenção indeterminada 4,6%, e casos de intervenção legal 1,3%. Após a complementação com o banco imprensa houve aumento nos óbitos por acidentes de automóveis (220,0% e motos (100,0%, o que resultou em diminuição do número de óbitos por causa indeterminada e por acidentes de transporte não especificados notificados no Sistema de Informações de Mortalidade. CONCLUSÕES: Notícias de jornais têm grande potencial para qualificar e complementar a causa básica de morte em óbitos por causas externas no Sistema de Informações de Mortalidade, principalmente daqueles por acidentes de transporte.

  3. El Enigma de las Causas de la Diabetes Mellitus Tipo 2 El Enigma de las Causas de la Diabetes Mellitus Tipo 2

    Directory of Open Access Journals (Sweden)

    Juan Manuel Malacara

    2012-02-01

    Full Text Available Type 2 diabetes mellitus the most frequent metabolic disease, is induced by factors so far largely unknown. Genetic and environmental causes are implicated, among the latter obesity and sedentary life are the most important. The discovery of new hormones controlling food intake such as leptin, ghrelin and the YY3-36 peptide, are expected to provide new tools to reduce overfeeding. The genes associated with type 2 diabetes are intensively sought without success.It is possible that the genetic transmission is more complex than suppossed. The theory of the thrifty gene proposes an explanation for the increased obesity and diabetes in ethnic groups in transition from preindustrial to industrialized cultures. The theory of the fetal origins of adult disease, proposes that in the fetal life there is a window for metabolic programming under stress or caloric restriction. If the subject, however, at the adult life consumes excessive caloric intake, has a high risk for the metabolic syndrome. The mechanisms involved in insulin resistance are complex, and several molecules are under study as candidates to explain it. The diminution in insulin secretion is an other important factor for the initiation of type 2 diabetes. Glucotoxicity and lipotoxicity are factors that further reduce insulin secretion. Recent evidence indicates that inflammation is implicated in the onset of both diabetes and atherosclerosis. The elucidation of the nature of this process, as well as the pathways involved will be another important tool for a better management of this disease.La causa de la diabetes mellitus tipo 2, la enfermedad metabólica más frecuente, no es bien conocida. Tiene un componente genético y otro ambiental, en éste destacan la obesidad y el sedentarismo. El conocimiento de las nuevas hormonas que controlan la alimentación: la leptina, la ghrelina y el péptido YY3-36, es una esperanza para el control de la obesidad. No se han identificado los genes

  4. O "hum" venoso como causa de zumbido pulsátil de origem vascular

    Directory of Open Access Journals (Sweden)

    Dib Gabriel Cesar

    2004-01-01

    Full Text Available Zumbido é uma das queixas otológicas mais comuns com que o otorrinolaringologista se depara. O "hum" venoso é descrito como uma causa pouco comum de zumbido vascular, pouco lembrado ou reconhecido como entidade clínica. OBJETIVO: O objetivo do estudo é identificar os casos de "hum" venoso dentre os pacientes com zumbido pulsátil atendidos no Ambulatório de Zumbido da Disciplina de Otorrinolaringologia da UNIFESP-EPM e compará-los com a literatura. MATERIAL E MÉTODO: Estudo retrospectivo dos pacientes com "hum" venoso realizado na UNIFESP-EPM de abril de 1997 a abril de 2003, analisando-se os parâmetros: idade de aparecimento, freqüência, lado acometido, presença de perda auditiva e tontura associadas, fatores de piora e melhora, resultados de audiometria, exame vestibular e tomografia computadorizada de ossos temporais, evolução e tratamento realizados. Foi utilizado um protocolo de exames e tratamento e os resultados foram comparados com os da literatura. RESULTADOS: O zumbido pulsátil ocorreu em 7,5% e o "hum" venoso em 3% do total de pacientes com zumbido, todos no sexo feminino, sem prevalência por época de aparecimento, acometendo mais a orelha esquerda. Em todos os pacientes houve melhora com tratamento clínico, não sendo necessária intervenção cirúrgica em nenhum caso. CONCLUSÃO: O "hum" venoso não é uma causa incomum de zumbido (39% dos zumbidos pulsáteis como citado na literatura. O tratamento deve ser realizado atuando-se sobre os fatores responsáveis pelo zumbido e decorrentes do mesmo. Em grande número de casos o mesmo desaparece espontaneamente, não necessitando de tratamento. O tratamento cirúrgico raramente é necessário, devendo ser reservado apenas aos casos em que não haja melhora com o tratamento clínico.

  5. Las enfermedades neoplásicas como causa de la incapacidad permanente

    Directory of Open Access Journals (Sweden)

    A. Ares Camerino

    2008-03-01

    Full Text Available El cáncer es la primera causa de mortalidad en hombres y la segunda en mujeres, tras las enfermedades cardiovasculares. Desde el punto de vista económico, los costes atribuibles a las enfermedades neoplásicas son principalmente indirectos (pérdida de productividad asociada a la mortalidad o a la incapacidad permanente. Analizando las incapacidades permanentes producidas en la Diputación Provincial de Cádiz en el período 1990-2005, que fueron un total de 208, se concluye, por orden de frecuencia, que las enfermedades neoplásicas se sitúan en tercer lugar (17,87%, precedidas de las enfermedades osteomusculares (24,15% y de las enfermedades cardiovasculares (23,67%. En cuanto a la pérdida de años e vida laboral, las enfermedades neoplásicas ocupan el segundo lugar con 11,24 años, detrás de las enfermedades psiquiátricas con 14,18 años. Por sexos las causas de incapacidad permanente se distribuyeron por el siguiente orden decreciente. En mujeres: enfermedades osteomusculares (39,08%, enfermedades neoplásicas (19,54% y enfermedades cardiovasculares (16,09%. En hombres: enfermedades cardiovasculares (28,93%, enfermedades neoplásicas (16,53% y enfermedades osteomusculares (13,22%.The cancer is the first cause of mortality in men and second in women, after the cardiovascular diseases. From the economic point of view, the costs attributable to the cancer diseases are mainly indirect (loss of productivity associated to mortality or the permanent incapacity. Analysing the produced permanent incapacities in the Provincial Delegation of Cadiz in period 1990-2005, that were a total of 208, one concludes, by frequency order, which the cancer diseases are located thirdly (17.87%, preceded of the diseases osteomusculares (24.15% and of the cardiovascular diseases (23.67%. As far as the loss of years and labour life, the cancer diseases occupy the second place with 11.24 years, behind the psychiatric diseases with 14.18 years. By sexes the

  6. A paixão da causalidade: uma fala em causa?,

    Directory of Open Access Journals (Sweden)

    Roland Gori

    Full Text Available Este artigo coloca a questão de saber de onde provém a neces- sidade de se buscarem causas psicológicas para o sofrimento e para a doença, transformando o pathos dessas experiências cruciais na busca de uma explicação aceitável pela razão. Partindo de fragmen- tos clínicos e da análise do texto de Tausk sobre "a gênese do apare- lho de influenciar" na esquizofrenia, o trabalho visa explicitar a especificidade da posição psicanalítica em relação às proposições psicológicas (por vezes influenciadas pela própria psicanálise, de caráter explicativo e "compreensivo", face a esta questão. Propõe-se que "a tendência causalista em psicanálise consti- tui uma resistência ao próprio método psicanalítico " e que é exigido do psicanalista um trabalho particular de luto consistindo na re- núncia a pretensão aos sentidos estabelecidos de uma vez por todas em benefício de se admitir, a partir do contexto da situação psicana- lítica, que podemos "sofrer sem razão" e que nosso pensamento se forma "do encontro de nosso desejo com alguns fragmentos, retos de palavras e de fonemas". Conclui-se que a necessidade de se encontrar causas psicoló- gicas para o sofrimento decorre da própria experiência originária de aquisição da linguagem, tempo mítico durante o qual um único aparelho de linguagem funcionou para dois corpos, fundador da relação desnaturada do ser humano com seu próprio corpo, para a qual o eu busca - desesperadamente - uma explicação definitiva.

  7. Effect of dentin-cleaning techniques on the shear bond strength of self-adhesive resin luting cement to dentin.

    Science.gov (United States)

    Santos, M J M C; Bapoo, H; Rizkalla, A S; Santos, G C

    2011-01-01

    This in vitro study evaluated the influence of different cleansing techniques on the bond strength of self-adhesive cement to dentin. A total of 33 noncarious human molars were sectioned mesiodistally and embedded in chemically cured resin with the buccal or lingual surfaces facing upward. Superficial dentin was exposed and resin disk provisional restorations were cemented to the dentin surfaces with noneugenol provisional cement and were stored in distilled water at 37°C. After seven days, the provisional restorations were removed and 13 specimens were randomly assigned to each of the five groups (n=13), according to the following cleansing treatments: G1-excavator (control); G2-0.12% chlorhexidine digluconate; G3-40% polyacrylic acid; G4-mixture of flour pumice and water; and G5-sandblasting with 50 μm aluminum oxide particles at a pressure of 87 psi. Resin composite disks (Filtek Supreme Plus, 3M ESPE Dental Products, St Paul, MN, USA) 4.7 (±0.1) mm in diameter and 3.0 (±0.5) mm in height were cemented with self-adhesive cement (RelyX Unicem, 3M ESPE), photocured, and stored in distilled water at 37°C for 24 hours. Shear bond strength testing was conducted using a universal test machine at a crosshead speed of 0.5 mm/min until failure. Data were analyzed using analysis of variance (ANOVA) and the Tukey-B rank order test. Sandblasting with aluminum oxide (11.32 ± 1.70 MPa) produced significantly higher shear bond strength values compared with any other treatment groups (p<0.05). No significant differences were found between G1-control (7.74 ± 1.72 MPa), G2-chlorhexidine (6.37 ± 1.47 MPa), and G4-pumice (7.33 ± 2.85 MPa) (p<0.05).

  8. Causas da variabilidade do tempo de execução dos processos em diferentes sistemas construtivos

    Directory of Open Access Journals (Sweden)

    Herbert Melo Cruz

    Full Text Available Resumo Um dos grandes desafios para o gerenciamento da construção é a execução das atividades de acordo com as durações programadas, sendo comum a ocorrência de variabilidade. O objetivo desta pesquisa foi analisar as causas da variabilidade do tempo de execução dos processos em diferentes sistemas construtivos, classificando-as em níveis de risco. A metodologia consistiu em um estudo de casos múltiplos em diferentes sistemas construtivos, sendo aplicado com diversos trabalhadores de obras um questionário com 31 causas de variabilidade divididas em oito categorias. Visou-se levantar as variáveis frequência e intensidade de atraso. Foram observadas obras de concreto armado (convencional, alvenaria estrutural e paredes de concreto moldadas no local. Para a análise dos dados foi criado um fator de atraso e aplicada uma metodologia de classificação das causas em níveis de risco através da análise de clusters. Como resultados foram apontadas as principais causas de variabilidade para cada um dos sistemas, sendo algumas semelhantes: retrabalho, baixa qualidade do trabalho e socialização. Análises estatísticas apontaram diferenças entre os sistemas: aqueles mais industrializados tiveram maior quantidade de causas classificadas em níveis de alto risco, porém o impacto da variabilidade no processo foi menor. Há deficiências por parte dos gestores para lidar com os impactos da variabilidade nos processos.

  9. A incidência real da causa na psicanálise The real incidence of the cause in psychoanalysis

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    Fernanda Costa-Moura

    2006-06-01

    Full Text Available O artigo trata da articulação da noção de causa na psicanálise a partir do Seminário A Angústia de Lacan e de referências feitas ao problema da causalidade em Kant naquele contexto. Busca-se identificar na função da causa a dimensão ontológica que Lacan relaciona ao conceito freudiano de inconsciente. Aborda-se a elaboração do objeto a, causa do desejo, a partir dos elementos da pulsão, para analisar qual foi, e para o que aponta a revisão do problema da causalidade proposta por Lacan. Concluindo por meio da indicação de que o que muda com a introdução da causa no campo do sujeito é a própria noção de causa.The concept of cause developed in Lacan's Seminar On Anguish is examined in the context of the landmark contribution to the philosophical discussion on causality that is brought by Kant and argued by Lacan. We investigate the ontological dimension of causality that Lacan relates to the Freudian notion of Unconscious. In this direction, the article aims at the structure of the object "petit a", cause of the desire, as it derives from the elements of the drive, to show the importance of Lacan's formulations of the cause and to indicate that this process touches and transforms not only the field of the subject but the concept of cause itself.

  10. Shear Bond Strength of Composite to Nd-YAG Lased Dentin with and without Dye

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    H. Kermanshah

    2004-06-01

    Full Text Available Statement of Problem: The achievement of a good and durable dentin/composite resin bond is an important task in restorative dentistry. The application of acid conditioners and dentin bonding agents is an accepted method to enhance this bond strength. Pretreating of dentin surface by laser irradiation seems to be a supplemental way to obtain better results,since lased dentin is more roughened and has a widest surface area to interact with acidconditioner.Purpose: In this study, the effect of dentin surface pretreating by Nd-YAG laser on dentin/composite shear bond strength was examined. Moreover, the effect of Chinese ink as a surface energy absorber on this value was investigated.Methods and Materials: Thirty-nine freshly extracted human teeth without dentinal caries were collected and their occlusal dentins were exposed using a diamond disk. The collected samples were divided into three identical groups. The dentin surface of the first group was lased by an Nd-YAG pulsed laser (100 mJ, 20 Hz through a 320 mm fiber optic in a swiping movement. In the second group, 10% solution of Chinese ink was applied on the dentinal surface before lasing. The samples of the third group were not lased at all. Thedentinal surface prepared by 35% phosphoric acid and Scotchbond MP primer and adhesive. Then, composite resin was cured on dentinal surface. After incubation, in water at 37°C for 24 hours, the samples were tested by Digital Tritest ELE machine.Results: The values of bond strength were 20.83±3.96 MPa, 17.83±3.63 MPa and 19.38±4.88 MPa for the lased, unlased and dye-enhanced groups, respectively. The results were not significant by ANOVA test (a=0.05. Although in the Weiboul modulus, the lased group offered better bond strength.Conclusion: Further studies are required to determine whether chemical as well as physical alterations to the dentin surface are induced by laser etching, and whether these influence the performance of the range of dentin

  11. Investigation of dentin hardness in roots exhibiting the butterfly effect.

    Science.gov (United States)

    Russell, Assil A; Chris He, Li Hong; Chandler, Nicholas P

    2014-06-01

    Most vertical root fractures occur in root canal treated teeth, and they usually run in a buccolingual direction. The butterfly effect is an optical phenomenon seen in some sections of tooth roots. The aim was to investigate the microhardness of dentin in mesiodistal and buccolingual cross sections of roots exhibiting the effect. Thirty extracted single-rooted teeth were allocated according to patient age: group 1, 15-24 years; group 2, 25-44 years; and group 3, 45 years and older. Roots were embedded in acrylic and cut into ten 1-mm-thick cross sections. Sections were viewed under a light microscope and coded (1 or 2) according to presence or absence of the butterfly effect. A root scored 20 when all levels featured the butterfly appearance. The 2 teeth with the highest score from each group and 2 control teeth with the minimum score (10) were selected. Two adjacent, consecutive cross sections were chosen from the middle of the roots. Vickers microhardness testing was carried out on the dentin walls. Mean hardness scores were highest mesiodistally (83.7 kgf/mm(2)) and lowest buccolingually (56.4 kgf/mm(2)), a significant difference (P = .028). This trend was found across all age groups. Root sections with the butterfly effect are harder mesiodistally. This might explain the high prevalence of vertical root fractures that run buccolingually. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  12. Dentin Pre-Treatment to Suppress Microleakage of Amalgam Restorations

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    Yosi Kusuma Eriwati Arianto

    2015-10-01

    Full Text Available Diminished microleakage of amalgam-to-dentin preparations would benefit large populations in public health facilities. Prior studies demonstrated less microleakage for bonded amalgams than similarly bonded advanced composites among 30 different composite/bonding agent/storage conditions, Haller et al. showed that a combination of formaldehyde pre-treatment and glutaraldehyde-containing Syntac adhesive minimized microleakage. In the current study, CLass V restorations (groups of 10 formaldehyde-treated non carious human molars were filled with Valiant (Ivoclar NA amalgam after application of one of three liners: Copalite varnish; Amalagambond Plus with microfiber; and Syntac/Variolink. The control group used no liner material. After 24 hours at 37°C/100% RH, samples were thermocycled (1000 eyeles in water at 5°C and 60°C (15 second dwell time in each. Samples were immersed in 5% methylene blue solution (4 hrs and observed under a stereomicroscope; interfaces also were examined by SEM. Krsukal Wallis ANOVA by ranks (P<0.01 and Mann Whitney U Tests (P<0.05 of the data indicate improvements (equivalent among the 3 different liners tested here over unlined amalgam preparations. Liner/aldehyde-crosslinked dentin interphases, without technique-sensitive composites, may minimize microleakage by improving amalgam contact (physical bonding.

  13. Diode laser irradiation increases microtensile bond strength of dentin

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    Rafael Massunari MAENOSONO

    2015-01-01

    Full Text Available Laser irradiation after the immediate application of dentin bonding systems (DBSs and prior to their polymerization has been proposed to increase bond strength. The objective of this study was to evaluate the effect of diode laser irradiation (λ = 970 nm on simplified DBSs through microtensile bond strength tests. Forty healthy human molars were randomly distributed among four groups (n = 10 according to DBSs used [Adper™ SingleBond 2 (SB and Adper™ EasyOne (EO], and the respective groups were irradiated with a diode laser (SB-L and EO-L. After bonding procedures and composite resin build-ups, teeth were stored in deionized water for 7 days and then sectioned to obtain stick-shaped specimens (1.0 mm2. The microtensile test was performed at 0.5 mm/min, yielding bond strength values in MPa, which were evaluated by two-way ANOVA followed by Tukey’s test (p < 0.05 for individual comparisons. For both adhesive systems, diode laser irradiation promoted significant increases in bond strength values (SB: 33.49 ± 6.77; SB-L: 43.69 ± 8.15; EO: 19.67 ± 5.86; EO-L: 29.87 ± 6.98. These results suggest that diode laser irradiation is a promising technique for achieving better performance of adhesive systems on dentin.

  14. Biodentine-a novel dentinal substitute for single visit apexification

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    Gurudutt Nayak

    2014-05-01

    Full Text Available Use of an apical plug in management of cases with open apices has gained popularity in recent years. Biodentine, a new calcium silicate-based material has recently been introduced as a dentine substitute, whenever original dentine is damaged. This case report describes single visit apexification in a maxillary central incisor with necrotic pulp and open apex using Biodentine as an apical barrier, and a synthetic collagen material as an internal matrix. Following canal cleaning and shaping, calcium hydroxide was placed as an intracanal medicament for 1 mon. This was followed by placement of small piece of absorbable collagen membrane beyond the root apex to serve as matrix. An apical plug of Biodentine of 5 mm thickness was placed against the matrix using pre-fitted hand pluggers. The remainder of canal was back-filled with thermoplasticized gutta-percha and access cavity was restored with composite resin followed by all-ceramic crown. One year follow-up revealed restored aesthetics and function, absence of clinical signs and symptoms, resolution of periapical rarefaction, and a thin layer of calcific tissue formed apical to the Biodentine barrier. The positive clinical outcome in this case is encouraging for the use of Biodentine as an apical plug in single visit apexification procedures.

  15. Biodentine-a novel dentinal substitute for single visit apexification

    Science.gov (United States)

    Hasan, Mohammad Faiz

    2014-01-01

    Use of an apical plug in management of cases with open apices has gained popularity in recent years. Biodentine, a new calcium silicate-based material has recently been introduced as a dentine substitute, whenever original dentine is damaged. This case report describes single visit apexification in a maxillary central incisor with necrotic pulp and open apex using Biodentine as an apical barrier, and a synthetic collagen material as an internal matrix. Following canal cleaning and shaping, calcium hydroxide was placed as an intracanal medicament for 1 mon. This was followed by placement of small piece of absorbable collagen membrane beyond the root apex to serve as matrix. An apical plug of Biodentine of 5 mm thickness was placed against the matrix using pre-fitted hand pluggers. The remainder of canal was back-filled with thermoplasticized gutta-percha and access cavity was restored with composite resin followed by all-ceramic crown. One year follow-up revealed restored aesthetics and function, absence of clinical signs and symptoms, resolution of periapical rarefaction, and a thin layer of calcific tissue formed apical to the Biodentine barrier. The positive clinical outcome in this case is encouraging for the use of Biodentine as an apical plug in single visit apexification procedures. PMID:24790925

  16. Dentin surface treatment using a non-thermal argon plasma brush for interfacial bonding improvement in composite restoration

    Science.gov (United States)

    Ritts, Andy Charles; Li, Hao; Yu, Qingsong; Xu, Changqi; Yao, Xiaomei; Hong, Liang; Wang, Yong

    2010-01-01

    The objective of this study is to investigate the treatment effects of non-thermal atmospheric gas plasmas on dentin surfaces for composite restoration. Extracted unerupted human third molars were used by removing the crowns and etching the exposed dentin surfaces with 35% phosphoric acid gel. The dentin surfaces were treated by using a non-thermal atmospheric argon plasma brush for various durations. The molecular changes of the dentin surfaces were analyzed using FTIR/ATR and an increase in carbonyl groups on dentin surfaces was detected with plasma treated dentin. Adper Single Bond Plus adhesive and Filtek Z250 dental composite were applied as directed. To evaluate the dentin/composite interfacial bonding, the teeth thus prepared were sectioned into micro-bars as the specimens for tensile test. Student Newman Keuls tests showed that the bonding strength of the composite restoration to peripheral dentin was significantly increased (by 64%) after 30 s plasma treatment. However, the bonding strength to plasma treated inner dentin did not show any improvement. It was found that plasma treatment of peripheral dentin surface up to 100 s gave an increase in interfacial bonding strength, while a prolong plasma treatment of dentin surfaces, e.g., 5 min treatments, showed a decrease in interfacial bonding strength. PMID:20831586

  17. [The combined occluding effect of fluor protector and Nd:YAG laser irradiation on human dentinal tubules].

    Science.gov (United States)

    Zhang, C; Lin, Q; Zhao, B

    2001-03-01

    To evaluate the combined occluding effect of fluor protector and Nd:YAG Laser irradiation on human dentinal tubules. Twenty-four dentin specimens with exposed dentinal tubule orifices treated by 37% H3PO4 were randomly divided into four groups. Group B, C and D were vanished by fluor protector, group A served as a control. Group D was lased by Nd:YAG laser. Group C and D were brushed with normal force. Under SEM, group A showed numerous exposed dentinal tubule orifices, the diameter of which is 2-3 microns. Group B showed closure of dentinal tubule orifices. Group C showed that most of the fluor protector were brushed away and group D showed over 80% of the dentinal tubule orifices were occluded. Fluor protector combined with Nd:YAG laser can make most of the dentinal tubule orifices occluded even after brushed.

  18. Hábeas Corpus: contribuciones a la causa del estado de derecho

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    Norma Bouyssou

    2016-09-01

    Full Text Available La garantía del hábeas corpus despliega, con total humildad, razones para la permanente expansión de la libertad o bien para su contínuo resguardo. Su bajo perfil, sin embargo, es confundido con indiferencia en orden a su compromiso con la causa de la ciencia del derecho; ello se explica, por un lado, debido a la generalizada creencia que su reconocimiento expreso como derecho positivo -en los más altos niveles normativos-, es anticuerpo suficiente para puestas en peligro o atentados directos contra la autonomía personal a manos del Estado y, por el otro, lógicamente anclado en el predio precedente, en una suerte de desubicación contemporánea frente a un punto de partida de contención teorético (y en desuso del abuso del poder político, al que no obstante se le exigen soluciones con mayor intervención fáctica (y menos frenos en las relaciones sociales, aunque necesariamente adecuadas al orden anterior. Corresponde exponer la disconformidad con los pies en claves propias a la ciencia jurídica, sin hacer a un lado lo pragmático, método dual que se aplicará sobre la excursión que sigue, a la que se invita.

  19. Causação Mental: Onde Estivemos e Onde Estamos

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    Amaral Felipe

    2001-01-01

    Full Text Available O presente trabalho tem como propósito situar o problema da causação mental dentro do debate contemporâneo em filosofia da mente. A partir dos trabalhos de autores como Smart, Putnam, Davidson e, principalmente Kim, delinearemos as mais importantes tentativas de solução do problema desde fins da década de cinqüenta. Defenderemos que a teoria da identidade, o funcionalismo e o monismo anômalo não se mostraram alternativas viáveis para o amelhoramento de nosso entendimento de como propriedades, ou tipos, mentais podem ter poder causal em um mundo físico. Concluiremos, por fim, que nem mesmo a superveniência mente-corpo, assim como indicado nos mais recentes trabalhos de Kim, foi capaz de oferecer uma saída satisfatória ao problema, colocando-nos assim diante de um impasse: abraçamos um projeto reducionista ou aceitamos o epifenomenismo do mental. Não apresentaremos uma defesa do projeto reducionista, porém sugeriremos que este nos parece menos problemático do que a alternativa epifenomenista.

  20. LA ADICCIÓN A LA PORNOGRAFÍA: CAUSAS Y CONSECUENCIAS

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    Angélica Velasco

    2017-01-01

    Full Text Available La pornografía puede definirse como el material audiovisual que presenta de forma explícita actividades sexuales y genitales de manera inocultable, con el objetivo de excitar al espectador. El objetivo de este trabajo es identificar las principales causas y consecuencias de la adicción a la pornografía en hombres y mujeres. Se empleó la metodología de la revisión sistemática de literatura (RSL, tomando como referencia investigaciones previas publicadas en bases de datos científicas y publicaciones web especializadas. Este trabajo concluye que la adicción a la pornografía puede generar problemas físicos, mentales, psicológicos y sociales, que son equiparables con los que genera la adicción al consumo de sustancias psicoactivas. Establecer estrategias de autocontrol, incrementar la actividad física y la participación en actividades sociales son algunas de las alternativas que pueden ayudar a combatir y prevenir la adicción.

  1. Causas de inasistencia a control prenatal: estudio descriptivo en Bogotá

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    Esguerra de Cárdenas Irene

    1991-12-01

    Full Text Available

    En el Instituto Materno Infantil de Santafé de Bogotá, se realizó este estudio de tipo descriptivo correlacional sobre "Causas por las cuáles las gestantes acuden tardíamente al control prenatal, reciben un número bajo de controles o no reciben ninguna atención de salud durante la gestación". Para ello se realizó una encuesta a 158 madres que estuvieron hospitalizadas en el servicio de puerperio durante el mes dedicado a la recolección de información y que cumplían con los criterios de selección establecidos. Además de las investigadoras participaron en esta etapa cinco estudiantes que cursaban la asignatura de Metodología de la Investigación. El análisis de datos permite destacar la presencia de factores biológicos, psicológicos y socioculturales como condicionantes de la inasistencia o asistencia tardía al control prenatal.

  2. Causação Mental: Onde Estivemos e Onde Estamos

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    Felipe Amaral

    Full Text Available O presente trabalho tem como propósito situar o problema da causação mental dentro do debate contemporâneo em filosofia da mente. A partir dos trabalhos de autores como Smart, Putnam, Davidson e, principalmente Kim, delinearemos as mais importantes tentativas de solução do problema desde fins da década de cinqüenta. Defenderemos que a teoria da identidade, o funcionalismo e o monismo anômalo não se mostraram alternativas viáveis para o amelhoramento de nosso entendimento de como propriedades, ou tipos, mentais podem ter poder causal em um mundo físico. Concluiremos, por fim, que nem mesmo a superveniência mente-corpo, assim como indicado nos mais recentes trabalhos de Kim, foi capaz de oferecer uma saída satisfatória ao problema, colocando-nos assim diante de um impasse: abraçamos um projeto reducionista ou aceitamos o epifenomenismo do mental. Não apresentaremos uma defesa do projeto reducionista, porém sugeriremos que este nos parece menos problemático do que a alternativa epifenomenista.

  3. Microorganism penetration in dentinal tubules of instrumented and retreated root canal walls. In vitro SEM study

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    Saad Al-Nazhan

    2014-11-01

    Full Text Available Objectives This in vitro study aimed to investigate the ability of Candida albicans (C. albicans and Enterococcus faecalis (E. faecalis to penetrate dentinal tubules of instrumented and retreated root canal surface of split human teeth. Materials and Methods Sixty intact extracted human single-rooted teeth were divided into 4 groups, negative control, positive control without canal instrumentation, instrumented, and retreated. Root canals in the instrumented group were enlarged with endodontic instruments, while root canals in the retreated group were enlarged, filled, and then removed the canal filling materials. The teeth were split longitudinally after canal preparation in 3 groups except the negative control group. The teeth were inoculated with both microorganisms separately and in combination. Teeth specimens were examined by scanning electron microscopy (SEM, and the depth of penetration into the dentinal tubules was assessed using the SMILE view software (JEOL Ltd. Results Penetration of C. albicans and E. faecalis into the dentinal tubules was observed in all 3 groups, although penetration was partially restricted by dentin debris of tubules in the instrumented group and remnants of canal filling materials in the retreated group. In all 3 groups, E. faecalis penetrated deeper into the dentinal tubules by way of cell division than C. albicans which built colonies and penetrated by means of hyphae. Conclusions Microorganisms can easily penetrate dentinal tubules of root canals with different appearance based on the microorganism size and status of dentinal tubules.

  4. Demineralized Xenogenic Dentin and Autogenous Bone as Onlay Grafts to Rabbit Tibia.

    Science.gov (United States)

    Al-Asfour, Adel; Farzad, Payam; Al-Musawi, Ala; Dahlin, Christer; Andersson, Lars

    2017-04-01

    The present study was undertaken to evaluate the healing pattern of xenogenic demineralized dentin onlay grafts in comparison with autogenous bone grafts to the rabbit tibia. Eight 6-month-old New Zealand male rabbits were used in the experiments. Standardized sized dentin blocks from human premolars and similar autogenous bone blocks harvested from tibia were grafted as onlay blocks on each tibia (n = 8 × 2). All animals were killed after a healing period of 12 weeks. Healing was uneventful for all animals. In general, both the dentin and bone block grafts were fused to the bone, resorbed, and replaced by bone and connective tissue to a varying degree. Both types of grafts were still present after 12 weeks, on an average to approximately one third of the original sizes. Resorption cavities could be seen in the dentin with bone formation. Zones of osseous replacement resorption of the dentin could be noted. In both graft types, higher rate of bone formation was seen at the interface between graft and recipient site. Demineralized xenogenic dentin onlay grafts showed similar resorption characteristics as autogenous bone onlay grafts, being resorbed in a similar rate during 12 weeks. New bone formation occurred mainly in terms of replacement resorption in the interface between dentin/bone graft and native bone.

  5. Dentin Morphology of Root Canal Surface: A Quantitative Evaluation Based on a Scanning Electronic Microscopy Study

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    Giuseppe Lo Giudice

    2015-01-01

    Full Text Available Dentin is a vital, hydrated composite tissue with structural components and properties that vary in the different topographic portions of the teeth. These variations have a significant implication for biomechanical teeth properties and for the adhesive systems utilized in conservative dentistry. The aim of this study is to analyse the root canal dentin going from coronal to apical zone to find the ratio between the intertubular dentin area and the surface occupied by dentin tubules varies. Observations were conducted on 30 healthy premolar teeth extracted for orthodontic reasons in patients aged between 10 and 14. A SEM analysis of the data obtained in different canal portions showed that, in the coronal zone, dentinal tubules had a greater diameter (4.32 μm than the middle zone (3.74 μm and the apical zone (1.73 μm. The average number of dentinal tubules (in an area of 1 mm2 was similar in coronal zone (46,798±10,644 and apical zone (45,192±10,888, while in the middle zone they were lower in number (30,940±7,651. However, intertubular dentin area was bigger going from apical to coronal portion. The differences between the analysed areas must be considered for the choice of the adhesive system.

  6. Effect of Dentin Wetness on the Bond Strength of Universal Adhesives

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    An-Na Choi

    2017-10-01

    Full Text Available The effects of dentin wetness on the bond strength and adhesive interface morphology of universal adhesives have been investigated using micro-tensile bond strength (μTBS testing and confocal laser scanning microscopy (CLSM. Seventy-two human third molars were wet ground to expose flat dentin surfaces. They were divided into three groups according to the air-drying time of the dentin surfaces: 0 (without air drying, 5, and 10 s. The dentin surfaces were then treated with three universal adhesives: G-Premio Bond, Single Bond Universal, and All-Bond Universal in self-etch or etch-and-rinse mode. After composite build up, a μTBS test was performed. One additional tooth was prepared for each group by staining the adhesives with 0.01 wt % of Rhodamine B fluorescent dye for CLSM analysis. The data were analyzed statistically using ANOVA and Tukey’s post hoc tests (α = 0.05. Two-way ANOVA showed significant differences among the adhesive systems and dentin moisture conditions. An interaction effect was also observed (p < 0.05. One-way ANOVA showed that All-Bond Universal was the only material influenced by the wetness of the dentin surfaces. Wetness of the dentin surface is a factor influencing the micro-tensile bond strength of universal adhesives.

  7. PLGA nanoparticles as chlorhexidine-delivery carrier to resin-dentin adhesive interface.

    Science.gov (United States)

    Priyadarshini, Balasankar Meera; Mitali, Kakran; Lu, Thong Beng; Handral, Harish K; Dubey, Nileshkumar; Fawzy, Amr S

    2017-07-01

    To characterize and deliver fabricated CHX-loaded PLGA-nanoparticles inside micron-sized dentinal-tubules of demineralized dentin-substrates and resin-dentin interface. Nanoparticles fabricated by emulsion evaporation were assessed in-vitro by different techniques. Delivery of drug-loaded nanoparticles to demineralized dentin substrates, interaction with collagen matrix, and ex-vivo CHX-release profiles using extracted teeth connected to experimental setup simulating pulpal hydrostatic pressure were investigated. Furthermore, nanoparticles association/interaction with a commercial dentin-adhesive applied to demineralized dentin substrates were examined. The results showed that the formulated nanoparticles demonstrated attractive physicochemical properties, low cytotoxicity, potent antibacterial efficacy, and slow degradation and gradual CHX release profiles. Nanoparticles delivered efficiently inside dentinal-tubules structure to sufficient depth (>10μm) against the simulated upward pulpal hydrostatic-pressure, even after bonding-resins infiltration and were attached/retained on collagen-fibrils. These results verified the potential significance of this newly introduced drug-delivery therapeutic strategy for future clinical applications and promote for a new era of future dental research. This innovative drug-delivery strategy has proven to be a reliable method for delivering treatments that could be elaborated for other clinical applications in adhesive and restorative dentistry. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  8. Demineralized Dentin as a Semi-Rigid Barrier for Guiding Periodontal Tissue Regeneration.

    Science.gov (United States)

    Qin, Xu; Zou, Fang; Chen, Weimin; Xu, Yiwen; Ma, Bo; Huang, Zhibin; Zhu, Guangxun; Zhou, Bin

    2015-12-01

    Guided tissue regeneration (GTR) is an accepted approach in the correction of periodontal bone loss. Nonetheless, the deficiencies of commonly applied absorbable membrane, such as flexibility and limited osteoconductive and osteoinductive capability, still leave much room for improvement. Thus, the feasibility of applying demineralized dentin tissue to improve the therapeutic effect of GTR in periodontal regeneration was explored. Demineralized dentin was harvested after acid treatment, and its physiochemical properties were assessed in terms of mineralization density, contact angle, three-point test, and cell attachment. Because of its similar characteristics with bone tissue, dentin that had been acid-treated for 6 hours was chosen to repair a periodontal defect using an induced-periodontitis canine model. Histologic measurements were taken to compare its therapeutic effects to an absorbable membrane group and an untreated group. The demineralized dentin displayed continually decreased hardness and density as the acid etching time was prolonged. Enhanced attachment and spreading of bone marrow mesenchymal stem cells were observed on the 6-hour processed dentin. Furthermore, in the demineralized dentin group, more periodontal tissues were newly formed compared with the biomembrane and untreated groups. Acid etching represents an easy and promising approach to obtain demineralized dentin with desirable properties, similar to bone, for clinical application to promote periodontal tissue regeneration.

  9. Effect of a one-step self-etch adhesive on endogenous dentin matrix metalloproteinases.

    Science.gov (United States)

    Apolonio, Fabianni M; Mazzoni, Annalisa; Angeloni, Valeria; Scaffa, Polliana M C; Santi, Spartaco; Saboia, Vicente de Paulo A; Tay, Franklin R; Pashley, David H; Breschi, Lorenzo

    2017-04-01

    Degradation of the hybrid layer created in dentin by dentin adhesives is caused by enzyme activities present within the dentin matrix that destroy unprotected collagen fibrils. The aim of the present study was to evaluate the effect of a one-step self-etch adhesive system on dentinal matrix metalloproteinases 2 and 4 (MMP-2 and MMP-9, respectively) using in situ zymography and an enzymatic activity assay. The null hypothesis tested was that there are no differences in the activities of dentinal MMPs before and after treatment with a one-step adhesive system. The MMP-2 and MMP-9 activities in dentin treated with the one-step adhesive, Adper Easy Bond, were quantified using an enzymatic activity assay system. The MMP activities within the hybrid layer created by the one-step adhesive tested were also evaluated using in situ zymography. The enzymatic assay revealed an increase in MMP-2 and MMP-9 activities after treatment with adhesive. In situ zymography indicated that gelatinolytic activity is present within the hybrid layer created with the one-step self-etch adhesive. The host-derived gelatinases were localized within the hybrid layer and remained active after the bonding procedure. It is concluded that the one-step self-etch adhesive investigated activates endogenous MMP-2 and MMP-9 with the dentin matrix, which may cause collagen degradation over time. © 2017 Eur J Oral Sci.

  10. Dental Pulp and Dentin Tissue Engineering and Regeneration – Advancement and Challenge

    Science.gov (United States)

    Huang, George T.-J.

    2012-01-01

    Hard tissue is difficult to repair especially dental structures. Tooth enamel is incapable of self-repairing whereas dentin and cememtum can regenerate with limited capacity. Enamel and dentin are commonly under the attack by caries. Extensive forms of caries destroy enamel and dentin and can lead to dental pulp infection. Entire pulp amputation followed by the pulp space disinfection and filled with an artificial rubber-like material is employed to treat the infection --commonly known as root canal or endodontic therapy. Regeneration of dentin relies on having vital pulps; however, regeneration of pulp tissue has been difficult as the tissue is encased in dentin without collateral blood supply except from the root apical end. With the advent of modern tissue engineering concept and the discovery of dental stem cells, regeneration of pulp and dentin has been tested. This article will review the recent endeavor on pulp and dentin tissue engineering and regeneration. The prospective outcome of the current advancement and challenge in this line of research will be discussed. PMID:21196351

  11. Effects of the pulsed fiber-optic-delivered Nd:YAG laser on dentin bonding

    Science.gov (United States)

    White, Joel M.; Goodis, Harold E.; Khosrovi, Paul; Rose, Chris M.

    1996-04-01

    Laser modification of the dentin may increase the mechanical retention of composite resin restorations. The purpose of this study was to evaluate the effect of the Nd:YAG laser on dentin bonding. 170 dentin specimens were prepared by horizontal sectioning through the middle coronal third of molars. A 5 mm area of 140 samples were treated at powers of 0.3 to 3.0 W, pulse frequencies of 10 to 30 Hz, and energies of 30 to 150 mJ/pulse. The remaining 30 were untreated dentin sections. Samples were pumiced and bonded with Scotchbond 2 and Silux Plus composite, then light cured and stored at 100% humidity for 24 hours prior to debonding. Shear bond strength was measured and the type of failure was determined. Laser modification of the dentin improved bond strength by 68% compared with the controls. Microscopic examination of the lased samples after debonding showed that 5% failed adhesively at the dentin-resin interface, while 95% failed cohesively within the resin. Therefore, lasers increased dentin bond strengths by improving micromechanical retention.

  12. Phenotype and genotype analyses in seven families with dentinogenesis imperfecta or dentin dysplasia.

    Science.gov (United States)

    Li, F; Liu, Y; Liu, H; Yang, J; Zhang, F; Feng, H

    2017-04-01

    Hereditary dentin defects can be categorised into two classes according to their clinical manifestations: dentinogenesis imperfecta (DGI), which includes three types (DGI-I, DGI-II and DGI-III), and dentin dysplasia (DD), which includes two types (DD-I and DD-II). This study investigated the phenotypic characteristics and genetic causes of hereditary dentin defects in seven Chinese families. Seven families affected with DGI-II, DGI-III or DD-II were enrolled. Clinical examinations were performed to determine the phenotypic characteristics, and DNA samples were collected for Sanger sequencing. Clinical diagnoses revealed DGI-II in five families, DGI-III in one family and DD-II in one family. Variants of the dentin sialophosphoprotein (DSPP) gene were found in six of the seven families. Of these, c.52G>T was identified in two families. Each of the remaining four families had a different variant: c.2684delG, c.52-2A>G, c.1874-1877delACAG and c.3509-3521del13bp; the last three variants were novel. This is the first study to analyse all three important types of hereditary dentin defect and include comprehensive genetic analyses of both dentin sialoprotein and dentin phosphoprotein in Chinese families. This study expands the spectrum of DSPP variants, highlighting their associated phenotypic continuum. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. The fractographic analysis of three dentin bonding agents on tooth surface

    Directory of Open Access Journals (Sweden)

    Adioro Soetojo

    2006-12-01

    Full Text Available The dentin bonding agent is hydrophilic resin that can strongly bind to dentin surface, both in chemical and physical-mechanical ways. The dentin surface is good for the resin bonding when the surface is in moist condition. Three types of dentin bonding agents: Voco, Prime & Bond NT and Excite were used in this research and their application methods are called as total-etched technique. The objective of this research is to examine the difference of tensile bond strength of the three bonding agents on the moist dentin surface. Bovine incisivus teeth were cut and sharpened using diamond bur then smoothened with sandpaper. Dentin surfaces were etched with 37% phosphoric acid, washed with 20 cc aquadest, and dried with blot-dry technique. The preparation teeth were inserted into desiccator with minimum humidity 60% and maximum 90% for one hour. After removed from the desiccator, the Voco agent was applied on the teeth in first group, and then followed by the Prime & Bond NT and Excite agents, respectively. The resulting sample was stored within the room temperature. After 24 hours, the tensile bond strength was tested using Autograph instrument. The results indicated that the tensile bond strength of Voco and Prime & Bond NT agents were higher than Excite both at humidity 60% and 90% (p ≤ 0.05. In conclusion, the dentin bonding agents with acetone solvents have a higher tensile bond strength compared with those with alcohol solvents.

  14. Solubility parameters, fractional polarities, and bond strengths of some intermediary resins used in dentin bonding.

    Science.gov (United States)

    Asmussen, E; Uno, S

    1993-03-01

    An effective bonding of resin composites to dentin is generally preceded by a conditioning of the surface of the dentin. Previous studies have indicated that the intermediary or adhesive resin should have specific wetting characteristics matching those of the conditioned dentin, in order that optimum bonding can be ensured. The wetting characteristics may be expressed in terms of solubility parameter (delta) and polarity (p) of the resin. The aims of the present study were to determine these variables for a number of compounds used in adhesive resins and to investigate the effects of delta and p on the shear bond strength to dentin. Solubility parameters were obtained according to the method of Small. Fractional polarities were calculated on the basis of measurements of refractive index and dielectric constant of the resins. In the measurements of bond strength, Scotchprep, EDTA + Gluma, or Al2Ox3/glycine were used as dentin conditioners in combination with intermediary resins having various delta and p. For each conditioner, the shear bond strength (BS) could be "explained" by an exponential expression of the form BS = e(a + bx), where x = (delta + cp + d)2, and where a-d are constants depending on the conditioned dentin. It may be concluded that solubility parameter and polarity of the intermediary resins are important variables in the process of bonding to dentin.

  15. Methods used in dentine bonding tests: an analysis of 102 investigations on bond strength.

    Science.gov (United States)

    Burke, F J Trevor; Hussain, Aftab; Nolan, Lawrence; Fleming, Garry J P

    2008-12-01

    Bond strength testing of resin-based materials to dentine may provide evidence as to the potential effectiveness of a dentine-bonding agent in producing adhesion and minimising microleakage. The purpose of this analysis was to analyse the methods used in 102 recently-published investigations on bond strength tests of resin composite to dentine. One hundred and two papers, published during the years 1998 to 2002 on the subject of bond strength measurement of resin composite to dentine were identified from a literature search. These papers were assessed for their inclusion of the following variables: type of test, thermal cycling regime, tooth notation, storage medium, preparation of dentine surface, rate of load application, type of dentine, film thickness, dimensions of surface area contact and time of testing. Shear testing was the most common type of test, used in 46% (n=47) of the papers analysed, human dentine was used in 77% (n=79) of the investigations, and 24 h post-placement was the predominant time of specimen testing (67%, n=68). Surface area of contact, or specimen diameter, was stated in 65% (n=66) of the papers analysed. A number of variables were not stated in a majority of papers. There was little standardization of test methods and a number of potentially significant variables may not be reported or recorded in bond strength determinations which limit the overall standardization between different test centres.

  16. The measurement of enamel and dentine abrasion by tooth whitening products using an in situ model.

    Science.gov (United States)

    Joiner, A; Collins, L Z; Cox, T F; Pickles, M J; Weader, E; Liscombe, C; Holt, J S

    2005-01-01

    To determine the enamel and dentine wear of two whitening toothpastes using an in situ model with ex vivo brushing. Human enamel/dentine (approximately 50:50) blocks (approximately 4 x 4mm) were placed in the upper buccal aspects of full or partial dentures of a group of 25 subjects. Subjects brushed the specimens ex vivo with either a calcium carbonate/perlite or silica containing whitening toothpaste under exaggerated conditions as compared to normal for 30 s, twice per day. Specimens were removed after 4, 8 and 12 weeks and the wear to the enamel and dentine was determined. Enamel wear was determined by change in Knoop indent length and dentine wear was determined from the enamel-dentine step height, measured using optical profilometry. The mean wear after 12 weeks was for enamel 0.27 and 0.19 microns, and for dentine 34.3 and 61.1 microns, for the calcium carbonate/perlite and silica toothpastes respectively. There were no significant differences between products after 12 weeks. The rate of wear was found to decrease throughout the duration of the study. There were no significant differences between the two whitening toothpastes in terms of enamel and dentine wear after 12 weeks brushing.

  17. Effect of aging on the microstructure, hardness and chemical composition of dentin.

    Science.gov (United States)

    Montoya, C; Arango-Santander, S; Peláez-Vargas, A; Arola, D; Ossa, E A

    2015-12-01

    Understanding the effects of biological aging on human tissues has been a topic of extensive research. With the increase in healthy seniors and quality of life that topic is becoming increasingly important. In this investigation the effects of aging on the microstructure, chemical composition and hardness of human coronal dentin was studied from a comparison of teeth within "young" and "old" age groups. The microstructure of dentin within three regions (i.e., inner, middle and outer) was analyzed using electron and optical microscopy. The mineral-to-collagen ratio in these three regions was estimated using Raman spectroscopy and the hardness was evaluated using microindentation. Results showed that there were significant differences in tubule density, tubule diameter and peritubular cuff diameter with depth. Although there was no difference in tubule density and diameter of the tubules between the age groups, there was a significant difference in the occlusion ratio. A significant increase in hardness between young and old patients was found for middle and outer dentin. An increase in mineral-to-collagen ratio from inner to outer dentin was also found for both groups. In old patients, an increase in mineral content was found in outer coronal dentin as a consequence of tubule occlusion. An increase in occlusion ratio, hardness, and mineral content was found in the dentin of adult patients with age. This increase is most evident in the outer coronal dentin. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Micro- and nanoscale structures of mesiodens dentin: Combined study of FTIR and SAXS/WAXS techniques.

    Science.gov (United States)

    Akgun, Ozlem Marti; Bayari, Sevgi Haman; Ide, Semra; Polat, Günseli Guven; Kalkhoran, Ilghar Orujalipoor

    2015-01-01

    A mesiodens is the most common type of supernumerary tooth present in conjunction to normal dentition. A mesiodens may commonly occur in the central region of the upper or lower jaw. A mesiodens is different from normal teeth in terms of structure and shape. The aim of this study is to evaluate the micro- and nanoscale structural properties of mesiodens dentin by combined small- and wide-angle X-ray scattering (SAXS/WAXS) and Fourier transform infrared (FTIR) spectroscopy. Five freshly extracted, noncarious mesiodens and five normal dentin disks prepared from human incisor teeth were compared. Using FTIR, the phosphate-to-amide I, carbonate-to-phosphate, and carbonate-to-amide I band area ratios and the crystallinity index were quantified. SAXS/WAXS were used to study the nanostructure of mesiodens. An increase in the mineral content in the mesiodens dentin with respect to the normal group was found. Crystallinity was also significantly increased and the protein content decreased in the mesiodens dentin compared with that of normal dentin. SAXS/WAXS results revealed that mesiodens dentin has a more calcified tissue. Further, SAXS analysis revealed a nonuniform distribution of dentin fibrils in mesiodens. © 2014 Wiley Periodicals, Inc.

  19. Pengaruh Kontaminsi Saliva terhadap Kekuatan Tarik antara Resin Komposit dengan Jaringan Dentin

    Directory of Open Access Journals (Sweden)

    Andi Soufyan

    2013-06-01

    Full Text Available Composite resin are restorative materials having color similar to teeth and have been widely used in dentistry. The successful application of composite resin influences the duration of the restoration in the oral cavity. The aim of this research is to describe the influence of artificial saliva contamination and the application of re-conditioning on tensile bond strength of composite resin to dentin. In the control group, the dentin were etched, bonding were applied and composite resin were restored on the dentin. In the group with artificial saliva contamination without re-conditioning, the dentin were etched, bonding were applied and then contaminated with artificial saliva, dried and then restired with composite resin. While the group with artificial saliva contamination with re-conditioning, the dentin were etched, bonding were applied and contaminated with artificial saliva, and then etched and applied bonding agent and restored composite resin.Bond strength test used “Universal testing machine, AG 5000. The results showed that highest value of tensile bond strength of composite resin to dentin was at the control group. It can be concluded that artificial saliva contamination decreased tensile bond strength while  re-conditioning application increased it.DOI: 10.14693/jdi.v15i2.69dentin

  20. [Observation and analysis of microstructure of dentin caries lesions through 3D laser scanning microscope].

    Science.gov (United States)

    Lixia, Xu; Hongmei, Xu; Xiaoying, Zhu; Limei, Sun

    2016-10-01

    Microstructural changes in dentin carious lesions were investigated using a 3D laser scanning microscope, which has a morphological theoretical foundation in the further study of clinical caries disease prevention and treatments. Six fresh extracted caries molars were prepared into cross-section specimens. The sections were examined by 3D and laser measuring morphology. Zones were identified in the lesions on the basis of their optical appearance. Two zones were identified in the lesions on the basis of their laser appearance. The microstructure showed that the tubular was partly closed in transparent dentin; peritubular and intertubular dentin were reduced in the zone of demineralization; peritubular and intertubular dentin were damaged and fused; a beaded sample and oval lesions formed in the zone of bacterial invasion; and abnormal dentin structure was present in the zone of destruction on the basis of their laser appearance. Four zones were iden-tified in the lesions according to their colors, as determined from their 3D appearance. 3D laser scanning micros-cope may be a powerful, accessible, and non-destructive technique, as it identified the lesion and tubular zones, as well as peritubular and intertubular dentin in the four zones' lesions. The microstructure of dentin caries lesions may have significant merit in the evaluation of clinical prevention and treatment.