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Interaction between toothbrushes and toothpaste abrasive particles in simulated tooth cleaning

Lewis, R., Dwyer-Joyce, R.S. and Pickles, M.J. (2004) Interaction between toothbrushes and toothpaste abrasive particles in simulated tooth cleaning. Wear, 257 (3-4). pp. 368-376. ISSN 00431648

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There are currently many toothbrush designs on the market incorporating different filament configurations such as filaments at various angles and different lengths and made from several different materials. In order to understand how the tooth cleaning process occurs there is a need to investigate in detail how the abrasive particles in a toothpaste interact with the filaments in a teeth cleaning contact and cause material removal from a plaque or stain layer. The following describes the development of optical apparatus to enable the visualisation of simulated teeth cleaning contacts. Studies have been carried out using the apparatus to investigate particle entrainment into the contact and how it differs with varying bristle configurations. The effects of filament stiffness and tip shape were also investigated. Various types of electric toothbrushes were also tested. The studies have shown how particles are trapped at the tips of toothbrush filaments. Particles, suspended in fluid, approach the filament tips, as they pass through they may become trapped. Greater particle entrainment into the filament tip contact occurs with a reciprocating action at low filament loads and deflections than with a sliding motion. Large particles are less likely to enter tip contacts and are trapped between tips or under the filament bend at higher loads. Whether the particles are likely to be trapped and how long they remain so depends on the filament stiffness and degree of splay on loading and the filament configuration. The direction the filaments point in, the number of filaments in a tuft, the spacing of the tufts and the way the filaments splay when deflected all have an influence on entrainment of particles. Tufts with tightly packed stiff filaments which deflected together on loading were more effective at trapping particles than more flexible filaments that splayed out on loading as they present more of a barrier to particle entry and exit from the tip region.

Item Type: Article
Copyright, Publisher and Additional Information: Copyright (c) 2004 Elsevier Science B.V. Amsterdam. This is an author produced version of a paper published in Wear. Uploaded in accordance with the publisher's self-archiving policy.
Institution: The University of Sheffield
Academic Units: The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Mechanical Engineering (Sheffield)
Depositing User: Mr Christopher Hardwick
Date Deposited: 20 Aug 2009 11:43
Last Modified: 08 Feb 2013 16:58
Published Version: http://dx.doi.org/10.1016/j.wear.2004.01.015
Status: Published
Publisher: Elsevier Science B.V.
Refereed: Yes
Identification Number: 10.1016/j.wear.2004.01.015
URI: http://eprints.whiterose.ac.uk/id/eprint/9187

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