Periodontitis is one of the most common oral diseases and is characterised by gingival inflammation and alveolar bone resorption (Savage et al. 2009). Periodontitis is a multifactorial irreversible and cumulative condition, initiated and propagated by bacteria and host factors (Kinane 2001). More than 500 different bacterial species are able to colonise the oral biofilm and up to 150 different species of bacteria are possible in any individual’s subgingival plaque. There are two forms of periodontitis; chronic and aggressive periodontitis which differ from each other not only in clinical findings but also age of onset and rate of progression. Chronic periodontitis progresses more slowly compared to the aggressive forms. | r M Intelligent Business Skills Book Longman Upper Intermediate Business English Christine Johnson Irene Barrall Economist The SIÌ Intelligent Business Skills Book Upper Intermediate Business English I Christine Johnson I Irene Barrall I Pearson Education Limited Edinburgh Gate Harlow Essex CM20 2JE England and Associated Companies throughout the world. Pearson Education Limited 2006 The right of Christine Johnson and Irene Barrall to be identified as authors of this Work has been asserted by them in accordance with the Copyright Designs and Patents Act 1988. All rights reserved no part of this publication may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic mechanical photocopying recording or otherwise without the prior written permission of the Publishers. First published 2006 Intelligent Business Upper-Intermediate Skills Book for pack. ISBN-13 978-0-582-84806-1 ISBN-10 0-582-84806-7 Intelligent Business Upper-Intermediate Skills Book and CD-ROM pack. ISBN-13 978-0-582-84696-8 ISBN-10 0-582-84696-x Set in Economist Roman Printed in Spain by Graficas Estella Acknowledgements The authors would like to thank Tony Garside and Stephen Nicholl for their excellent editorial support. The publishers would like to thank the following people for their helpful comments on the manuscript for this book Louise Bulloch Intercom Language Services GmbH Steve Bush The British Institute Florence William Cooley Open Schools of Languages Madrid Peter Dunn Groupe ESC Dijon Bourgogne Jolanta Korc-Migoh Warsaw University of Technology Louise Pile UK. The publishers would like to thank the following people for their help in piloting and developing this course Richard Booker and Karen Ngeow University of Hong Kong Adolfo Escuder EU Estudios Empresariales University of Zaragoza Wendy Farrar Università Cattolica del Sacro Cuore Piacenza Andrew Hopgood Linguarama Hamburg Ann-Marie Hadzima Dept of .
