نتایج جستجو برای: enamel crack

تعداد نتایج: 34861  

In the vibration of a cracked structure with small amplitude oscillations, the crack necessarily is not fully open or fully closed. Therefore, in order to provide a realistic model for the crack, one should relate the stiffness and damping at the crack location to the amount of the opening of the crack. In this study, a continuous model for vibration of a beam with a fatigue crack under low amp...

Journal: :iranian journal of science and technology transactions of mechanical engineering 2015
f. azimpour h. akbulut h. ghaffarzadeh jahanpasand h. akbari khantakhti

nowadays, textile and woven fabric composites are taken into consideration forapplications in high mechanical properties and every in-plane direction. however, developments inmodelling and characterisation of the fabric reinforced composite materials are considered more inthe effects of element types used in the mesh generation of the crack tip. the type of elementselected for the crack tip, a ...

Journal: :Journal of dentistry 2010
Rami A Farah Brian C Monk Michael V Swain Bernadette K Drummond

OBJECTIVES The aim of the study was to compare the relative amounts and nature of the proteinous content of sound and molar-incisor hypomineralisation (MIH) enamel. METHODS TCA (20%) was used to dissolve the mineral phase and precipitate the proteins from enamel pieces sectioned from sound and MIH enamel. The protein content was estimated using a miniaturized version of the method of Lowry et...

Journal: :European journal of oral sciences 2011
Yuanyuan Hu Jan C-C Hu Charles E Smith John D Bartlett James P Simmer

The crowns of matrix metalloproteinase 20 (Mmp20) null mice fracture at the dentino-enamel junction (DEJ), whereas the crowns of kallikrein-related peptidase 4 (Klk4) null mice fracture in the deep enamel just above the DEJ. We used backscatter scanning electron microscopy to assess enamel mineralization in incisors from 9-wk-old wild-type, Klk4 null, and Mmp20 null mice, and in developing pig ...

Journal: :American journal of physical anthropology 2008
A J Olejniczak T M Smith W Wang R Potts R Ciochon O Kullmer F Schrenk J-J Hublin

Absolutely thick molar enamel is consistent with large body size estimates and dietary inferences about Gigantopithecus blacki, which focus on tough or fibrous vegetation. In this study, 10 G. blacki molars demonstrating various stages of attrition were imaged using high-resolution microtomography. Three-dimensional average enamel thickness and relative enamel thickness measurements were record...

Journal: :Optics express 2008
Szu-Yu Chen Chin-Ying S Hsu Chi-Kuang Sun

Enamel covers the tooth crown and is responsible for protecting the inner tissues of the teeth. It is thus clinically important to diagnose the anomalies in tooth enamel structures in the early stage for prevention and treatment. In this article, we report the epi-harmonic-generation-microscopic study of various abnormal enamel from the nature surface of human teeth. With a 1230 nm light source...

Journal: :American journal of physical anthropology 2011
Patrick Mahoney

Quantitative studies of incremental markings retained within human enamel have reconstructed the duration and rate (crown and cusp formation times, initiation and completion, daily enamel secretion rates) of permanent tooth development. This approach has provided one way of estimating human age-at-death, and facilitated comparative dental studies of primate evolution. Similar applications from ...

Journal: :The international journal of esthetic dentistry 2014
Federico Ferraris Sofia Diamantopoulou Raffaele Acunzo Renato Alcidi

OBJECTIVES To evaluate the influence of thickness on the optical properties of two enamel shade composites, one with a high refractive index and one traditional. METHODS A medium value enamel shade was selected from the resin composites Enamel Plus HRi (UE2) and Enamel Plus HFO (GE2). Enamel Plus HRi is a high refractive index composite. Samples were fabricated in five different thicknesses: ...

1998
Ting Zhu Wei Yang

Fatigue crack growth has been observed recently in ferroelectrics under cyclic electric loading[ Does the crack grow by electric breakdown\ or by the stress _eld near the crack tip< The present paper provides a mechanistic explanation for the electric!_eld!induced fatigue crack growth[ The non!uniform electric _eld near an insulated crack tip might cause domain switching which in turn produces ...

Journal: :Journal of dental research 1998
M L Paine P H Krebsbach L S Chen C T Paine Y Yamada D Deutsch M L Snead

Enamel crystallites form in a protein matrix located proximal to the ameloblast cell layer. This unique organic extracellular matrix is constructed from structural protein components biosynthesized and secreted by ameloblasts. To date, three distinct classes of enamel matrix proteins have been cloned. These are the amelogenins, tuftelin, and ameloblastin, with recent data implicating ameloblast...

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