The Scientific Basis of Oral Health Education

The first edition of this classic text appeared in 1976 with the aim of refining and standardising the advice given to the public and to ensure that such advice was scientifically sound and evidence-based. It was written not only for members of the dental professions and those involved in general healthcare including medical practitioners, school nurses, health visitors, midwives, dieticians, pharmacists and public health practitioners, but also those who influence health in the wider community, such as teachers, child carers and peer educators. While originally written for a UK readership it became clear that it was used in other countries and that a new international edition was needed. To ensure that this new edition would reflect a consensus of international expert opinion and be relevant to a much broader readership, a panel of eminent experts was enlisted from as far afield as Japan, Singapore, Denmark, Switzerland and the USA. The text is consistent with current evidence and guidance from the WHO, and includes comparative guidance from other countries and systematic reviews of research evidence from the Cochrane Collaboration database. It provides information and advice on the main aspects of oral health, including the cause and prevention of dental caries, periodontal disease, dental erosion, oral cancer and dental problems in children under five, and older people. Throughout the book, key points are given at the beginning of each chapter, with an indication of the strength of supporting scientific evidence using a simple scheme.


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BDJ Clinician’s Guides

Ronnie Levine Catherine Stillman-Lowe

The Scientific Basis of Oral Health Education Eighth Edition

BDJ Clinician’s Guides

More information about this series at http://www.springer.com/series/15753

Ronnie Levine • Catherine Stillman-Lowe

The Scientific Basis of Oral Health Education Eighth Edition (International)

Ronnie Levine, OBE Department of Oral Surgery University of Leeds Leeds West Yorkshire United Kingdom

Catherine Stillman-Lowe Reading Berkshire United Kingdom

This book has been previously published in 2014 by BDJ Books with the following title: The Scientific Basis of Oral Health Education, 7th edition. ISSN 2523-3327     ISSN 2523-3335 (electronic) BDJ Clinician’s Guides ISBN 978-3-319-98206-9    ISBN 978-3-319-98207-6 (eBook) https://doi.org/10.1007/978-3-319-98207-6 Library of Congress Control Number: 2018957097 © Springer Nature Switzerland AG 2019 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland

This new international edition of The Scientific Basis of Oral Health Education is dedicated to the memory of Professor Aubrey Sheiham whose enthusiastic support for this document and sound advice for over 40 years were greatly appreciated. He will always be remembered for his forthright views, objective thinking and his resolute campaigning against health inequalities. “The good that men do lives after them” —Eberle 1917

Preface

The first edition of The Scientific Basis of Dental Health Education appeared in 1976 and was a slim booklet with a green cover. It arose from a joint attempt by the British Association for the Study of Community Dentistry and the UK Health Education Council, who published it, to refine and standardise the advice given to the public and to ensure that such advice was scientifically sound. The need for this document grew from the problem of confusing and sometimes conflicting dental health education messages being provided by professional and commercial bodies. The strength of the original document was that it came from an independent and authoritative source and was based on a consensus of scientific opinion from a group of the UK’s leading dental experts of the day. Over the intervening 40 years, the document has grown through six further editions to become one of the most widely used and accepted sources of information on oral health, both in the UK and abroad. The scientific evidence on the causes and prevention of oral disease is constantly evolving, and this new edition updates the evidence base for the range of topics previously covered. While the previous editions were primarily written for a UK readership, their use in many other countries is recognised in this new edition by the inclusion of more information, evidence and opinion from international sources. The key messages given in the summary section below include a fifth on tobacco use cessation to highlight the importance of tobacco as a risk factor for oral disease. Prominence is given to the concept of common risk factors that link oral disease with other non-communicable diseases together with highlighting the inequalities in oral health around the world. The chapter on periodontal disease includes a section on the association with obesity and diabetes, which together with tobacco use are now recognised as important common risk factors. The prevention of oral cancer with its poor survival rate remains a priority for dental professionals, and the oral cancer chapter includes international data on prevalence and a section on the link between the human papilloma virus and oropharyngeal cancer. Finally, the reference list reflects the latest scientific evidence and opinion to support the key messages. To keep the book within a reasonable length, however, it does not attempt to cover the full scope of oral health promotion. Public Health England issues guidance on the prevention of oral disease to the dental team in the form of a document—Delivering better oral health: an evidence-based toolkit for prevention1, which gives a prescriptive guide to prevention in a primary care setting. This new vii

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international edition of The Scientific Basis of Oral Health Education provides the information and evidence to underpin this UK guidance, and care has been taken to ensure that the two documents are consistent and also consistent with international guidelines. As before, it is hoped that this new edition will be used both in the UK and abroad by dental schools, dental postgraduate deans and directors to help standardise undergraduate and postgraduate teaching and by dental care professionals, whose role within the dental team has developed significantly since 1976. Those involved in general healthcare, such as medical practitioners, school nurses, health visitors, midwives, dieticians and pharmacists, also have a vital role to play in oral health promotion. Oral health promotion staff in the public, private and the voluntary sectors frequently provide training for people who can influence health in the wider community, such as teachers, child carers and peer educators, and they can safely rely on the messages in this book as the basis for their programmes. Finally, it must be recognised that oral health education material is provided by a wide range of agencies, including government and professional bodies, charities and commercial organisations in the form of both patient education material and for product promotion, much of which is of the highest standard. This too should conform to agreed expert opinion, and it is hoped that this publication will be of assistance to these bodies and will reach a wider international readership. Above all, this document is offered in the sincere belief that oral health education is one of our most important responsibilities and must be approached with the same dedication and professional quality standards that are applied to the operative treatment of disease. Only by offering the public consistent and soundly based advice can we hope that health education messages achieve their intended function of enabling individuals to control and improve their own health, and to support the healthy growth and development of future generations. This must be achieved as part of a comprehensive programme of national and local public health initiatives designed to tackle the determinants of poor health and health inequalities. 1. Public Health England. Delivering better oral health: an evidence-based toolkit for prevention – summary guidance tables. Third edition. London: Public Health England, 2017. https://assets.publishing.service.gov.uk/government/uploads/ system/uploads/attachment_data/file/605266/Delivering_better_oral_health. pdf. Leeds, UK Reading, UK 

Ronnie Levine Catherine Stillman-Lowe

A Guide to Using This Book

The aim of this book is to provide a sound basis for giving information and advice on the main aspects of oral health. The summary that follows gives a brief overview of the main oral diseases and some other oral conditions, together with five key messages. These key messages are a consensus of expert opinion and should form the basis of all oral health advice given to the public and other professionals. Throughout this document, important statements are given at the beginning of each chapter in the form of key points. In order to indicate the level of supporting scientific evidence for each of these key points, a simple scheme called Evidence Base is used: • Evidence Base A: Statements supported by very strong evidence from systematic literature reviews and pooled research data (meta-analysis). • Evidence Base B: Statements supported by the majority of relevant research studies. • Evidence Base C: Statements that cannot be supported by a substantial body of research evidence, but where there is a consensus of scientific and professional opinion to support the statement. More detailed information on Evidence Base is given in Chap. 1, together with sections on health education and the nature of scientific evidence. Chapters 2–12 cover the various diseases that can affect the teeth and mouth as a whole together with information on their causes and means of prevention, including advice for the under-fives and older people.

Which Topics Are Included in This Document? Over the years, many requests had been received to include additional topics within The Scientific Basis of Oral Health Education document. To understand the problems involved in selecting topics for inclusion, it is helpful to consider possible topics under three headings:

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• Topics where a substantial body of scientific evidence is available to support a useful health education statement, an example being the use of fluoride toothpaste. • Topics where guidance for the public in the form of a health education message is required but where scientific evidence is lacking. Provided that there is a consensus of scientific opinion, a statement can be made, though this will be subject to change as new evidence and guidelines are published—an example being how often people should have a dental check-up. • Topics that require guidance for the public but where there is neither a substantial body of scientific evidence nor a consensus of opinion amongst experts. If experts cannot agree, then no statement can or should be given. An example is whether the teeth should be brushed before or after eating.

Summary Oral health is an integral part of general health. They share common risk factors for a number of diseases and both can benefit from similar changes in personal behaviour and public health initiatives aimed at improving the health of the present and future generations. The two most common oral diseases are tooth decay, dental caries, and gum disease, properly known as periodontal disease. The principal cause of dental caries is the frequent consumption of sugars, mainly in confectionery, snack foods and soft drinks, acting on the layer of bacteria that form on the tooth surface, commonly called plaque, but more correctly a biofilm. The sugars are rapidly converted into acid by the biofilm bacteria and the build-up of acid attacks the tooth surface causing a cavity and if untreated, destruction of the tooth with pain and possibly infection. The common form of periodontal disease is caused by poor oral hygiene, allowing bacteria in the plaque biofilm to build up around the necks of the teeth. The toxins released from the biofilm cause inflammation of the gums, a condition known as gingivitis. The later stage of periodontitis develops when the supporting bone around the teeth becomes progressively destroyed, so that the teeth become loose and painful. Tobacco use is now recognised as an important risk factor, as is diabetes, especially if poorly controlled. Unlike tooth decay, which is usually a rapid process, periodontal disease can take many years to reach the stage where teeth become loose and may be lost. Dental erosion, which causes wearing away of the surfaces of teeth, appears to be an increasing problem. The cause is usually acid in the soft drinks and juices increasingly being consumed by children and young adults, 50% of whom are now affected to some degree. Erosion can also be caused by gastric regurgitation, as can occur in pregnancy, or due to conditions such as hiatus hernia or bulimia. The loss of teeth, whether due to caries, periodontal disease or dental erosion can affect not only masticatory function and nutrition, especially in the elderly, but facial development in children and the retention of facial features in adults, often with associated emotional and psychological changes.

A Guide to Using This Book

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There are many other diseases that occur in the mouth and there are some conditions arising elsewhere in the body that can have a visible effect within the mouth, such as anaemia and HIV infection (AIDS). The most life-threatening oral disease is oral cancer. This condition is increasing in prevalence in many countries and in parts of India it is the most common of all cancers in men. In the UK it is now more common than cervical cancer with over 6500 new cases each year, most being tobacco or alcohol related. About half of these cases prove fatal, but early diagnosis greatly improves the chance of survival. Dental patients who wish to quit tobacco use and control alcohol consumption should be offered appropriate support to do so. More information on tobacco use cessation is provided in Appendix A. Dental disease is not an inevitable part of life and research has shown that much can be prevented by changes in behaviour. Such changes require knowledge and skills for people to make healthy choices and are influenced by social and economic pressures on individuals, communities and society, and this may account for the persistence of high levels of dental caries in economically depressed communities. To promote good oral health there are five key messages: 1. Diet: reduce the consumption and frequency of intake of drinks, confectionery and foods with free sugars. Evidence base B (Chaps. 2, 3 and Appendix B) The consumption of sugars, both the amount and frequency of intake and the way they are consumed are important in determining the rate of tooth decay. When sugars are consumed, they should be part of a meal rather than between meals. Snacks and drinks should be free of added sugars, whenever possible. The frequent consumption of acidic drinks (such as fruit juice, squashes or carbonated drinks) should be avoided to help prevent dental erosion. 2. Mouth hygiene—toothbrushing: clean the teeth thoroughly at least daily with a fluoride toothpaste. Evidence base A (Chaps. 2, 3 and 9) Daily toothbrushing with a fluoride toothpaste containing 1000–1450 parts per million of fluoride has been established as an effective way of preventing caries. Effective daily toothbrushing will also control plaque formation and help prevent periodontal disease. Other oral hygiene aids such as interdental brushes are best used after they have been demonstrated by a dentist, therapist or hygienist. There is some evidence that twice daily brushing with a fluoride toothpaste is more effective than once daily for caries prevention. Thorough brushing of all tooth surfaces and gum margins twice every day is of more value than more frequent cursory brushing. A small soft-to-medium texture toothbrush should be used to allow all tooth surfaces and gum margins to be cleaned easily and comfortably. 3. Fluoride: fluoridation of water, salt and milk supplies are safe effective public health measures. Evidence base A (Chap. 2) Water fluoridation should be targeted at communities with higher caries levels. Salt and milk are effective alternative vehicles for fluoride administration. Where it is not feasible other fluoride strategies should be employed, such as community and school-based programmes to promote the use of fluoride toothpaste.

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4. Dental attendance: have an oral examination at regular intervals. Evidence base C (Chap. 11) Everyone, irrespective of age and dental condition, should have an oral examination at regular intervals so that oral disease, including cancer and other diseases of the oral mucosa, can be detected early and treated. While there is little evidence on the ideal frequency of examinations, there is a general consensus that advised examination intervals should be based on an individual assessment of both general and oral health. Guidance given by local authorities varies according to country and region. In North America, a 6-monthly interval is considered appropriate for most individuals, while in the UK the advised intervals are no longer than 12 months for those under 18 years of age and no more than 24 months for all adults. Those without any natural teeth should also have their mouths examined at regular interval, and children and those at risk from oral disease, including smokers, may need to be seen more frequently. 5. Tobacco: encourage tobacco use cessation. Evidence base A (Chaps. 4, 7 and Appendix A) Periodontal disease and oral cancers, as well as a wide range of chronic diseases, are strongly linked to tobacco use. It is an important role for the dental team to tell tobacco users of the risks and to assist them with cessation by referring them to specialist local tobacco cessation services.

Acknowledgments

As with the previous editions, a considerable debt of gratitude is owed to the panel of expert advisers, listed below. It is the involvement of expert advisors, some giving specialist advice and others a general perspective, that has helped to establish this document as an authoritative resource for over 40 years. With this new international edition, we have been most fortunate in having had the advice of eminent and distinguished experts from as far afield as Japan and the USA who graciously agreed to assist with this project, as have several experts who assisted with previous editions. All have been most generous with their time, advice and suggestions, assiduously checking the text as it evolved through various drafts, to help ensure that the whole document is consistent with current evidence and that it remains a consensus of expert opinion. We are also grateful to others who provided specific advice, including Mr. T.K. Ong, consultant oral and maxillo-facial surgeon, and Dr. Alan Mighell, senior lecturer in oral medicine, both of the Leeds University School of Dentistry and the Leeds Dental Institute, and Emily Beardall, pharmacist.

Panel of Expert Advisors • Professor R.J.  Genco, SUNY Distinguished Professor of Oral Biology, Microbiology and Immunology. Director, UB Microbiome Center, University at Buffalo, New York, USA. • Professor A.  Lussi, Chairman, Department of Preventive, Restorative and Pediatric Dentistry, University of Bern, Switzerland. • Professor Paula Moynihan, Faculty of Health and Medical Sciences, The University of Adelaide, South Australia. • Professor June Nunn, Emeritus Professor, School of Dental Science, Trinity College Dublin and the Dublin Dental University Hospital. Ireland. • Professor H. Ogawa, Department of Preventive Dentistry and WHO Collaborating Centre for Translation of Oral Health Science, Niigata University, Japan. • Professor P.E.  Petersen, WHO Regional Office for Europe, Copenhagen, Denmark, and WHO Collaborating Centre for Community Oral Health Programmes and Research, University of Copenhagen, Denmark.

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• Professor Philip M. Preshaw, Centre for Oral Health Research and Institute of Cellular Medicine, University of Newcastle upon Tyne, UK. • Professor Lone Schou, Discipline of Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore.

Contents

1

Health Education . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .   1 1.1 What Is Oral Health?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .   1 1.2 What Is Health Education? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .   2 1.3 The Common Risk Factor Approach. . . . . . . . . . . . . . . . . . . . . . . . . .   3 1.4 Does Health Education and Promotion Work? . . . . . . . . . . . . . . . . . .   4 1.5 Guidance on Oral Health Promotion. . . . . . . . . . . . . . . . . . . . . . . . . .   6 1.6 The Nature of Scientific Evidence. . . . . . . . . . . . . . . . . . . . . . . . . . . .   6 1.6.1 Laboratory-Based Studies. . . . . . . . . . . . . . . . . . . . . . . . . . . .   6 1.6.2 Clinical Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .   7 1.6.3 Community Studies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .   7 1.7 Health Education and Evidence-Based Dentistry . . . . . . . . . . . . . . . .   8 References����������������������������������������������������������������������������������������������������   9

2

Dental Caries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  11 2.1 Who Gets Caries? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  11 2.2 How Caries Affects Teeth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  13 2.3 Cause��������������������������������������������������������������������������������������������������  14 2.4 The Tooth’s Environment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  14 2.5 Diet������������������������������������������������������������������������������������������������������  16 2.5.1 Sugars in Our Diet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  16 2.5.2 Dietary Advice. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  17 2.5.3 Preferable Snacks and Drinks for Between-Meal Consumption��������������������������������������������������������������������������  17 2.6 The Tooth’s Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  18 2.7 Prevention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  18 2.8 Fluoride ����������������������������������������������������������������������������������������������  18 2.8.1 Fluoride Toothpaste. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  18 2.9 Water Fluoridation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  20 2.9.1 Other Fluoride Agents. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  22 2.9.2 Fluoride Tablets and Drops . . . . . . . . . . . . . . . . . . . . . . . . . . .  22 2.10 Fluoridated Milk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  24 2.11 Enamel Fluorosis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  24 2.12 Systemic Fluorosis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  25 2.13 How Does Fluoride Work?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  25 xv

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2.14 Plaque (Biofilm) Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  26 2.15 Fissure Sealants. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  26 References����������������������������������������������������������������������������������������������������  27 3

Diet and Oral Health . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  29 3.1 Sugars and Dental Caries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  29 3.2 Sugars in Food and Drinks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  30 3.3 Xylitol and Other Non-cariogenic Sweeteners . . . . . . . . . . . . . . . . . .  34 3.4 The Pattern of Free Sugar Intake. . . . . . . . . . . . . . . . . . . . . . . . . . . . .  35 References����������������������������������������������������������������������������������������������������  36

4

Periodontal Diseases. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  37 4.1 Cause��������������������������������������������������������������������������������������������������  38 4.2 Diabetes, Obesity and Periodontal Disease. . . . . . . . . . . . . . . . . . . . .  39 4.3 Plaque (Biofilm) Retention Factors. . . . . . . . . . . . . . . . . . . . . . . . . . .  40 4.4 Risk Factors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  40 4.5 Prevention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  41 4.5.1 What People Can Do for Themselves. . . . . . . . . . . . . . . . . . .  41 4.5.2 What Dental Professionals Can Do. . . . . . . . . . . . . . . . . . . . .  42 References����������������������������������������������������������������������������������������������������  43

5

Plaque (Biofilm) Control and Dental Diseases. . . . . . . . . . . . . . . . . . . . .  45 5.1 Plaque Removal for Children. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  45 5.2 Plaque Removal for Adults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  46 5.3 Recommended Toothbrush Specifications. . . . . . . . . . . . . . . . . . . . . .  47 5.4 Powered Toothbrushes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  47 5.5 Chemical Plaque Suppressants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  47 References����������������������������������������������������������������������������������������������������  48

6

Dental Erosion and Erosive Tooth Wear. . . . . . . . . . . . . . . . . . . . . . . . . .  49 6.1 Prevalence, Clinical Presentation and Assessment . . . . . . . . . . . . . . .  49 6.2 Aetiology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  52 6.3 Prevention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  54 6.4 Is There a Specific Waiting Period Recommended Before Brushing Teeth?����������������������������������������������������������������������  55 References����������������������������������������������������������������������������������������������������  56

7

Oral Cancers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  57 7.1 Oral Tumours. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  57 7.2 Squamous Cell Carcinoma. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  57 7.3 Other Oral Tumours. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  58 7.4 Prevalence and Prognosis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  58 7.5 Cause and Prevention. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  59 References����������������������������������������������������������������������������������������������������  61

8

Other Oral Diseases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  63 8.1 Oral Candidosis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  63 8.2 Oral Ulceration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  64

Contents

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8.3 White and Red Patches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  65 8.4 Dry Mouth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  65 9

Advice for Children Under 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  67 9.1 Breastfeeding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  67 9.2 Toothbrushing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  67 9.3 Drinks��������������������������������������������������������������������������������������������������  68 9.4 Teething����������������������������������������������������������������������������������������������  70 9.5 Weaning����������������������������������������������������������������������������������������������  70 9.6 Dental Visiting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  71 9.7 Fluoride Varnish for Children . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  71 References����������������������������������������������������������������������������������������������������  71

10 Advice for Denture Wearers and Older People. . . . . . . . . . . . . . . . . . . .  73 10.1 Denture Cleaning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  73 10.2 Root Caries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  74 References����������������������������������������������������������������������������������������������������  75 11 Frequency of Oral Examinations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  77 References����������������������������������������������������������������������������������������������������  78 12 First Aid for Traumatised Front Teeth. . . . . . . . . . . . . . . . . . . . . . . . . . .  79 Reference ����������������������������������������������������������������������������������������������������  80  ppendix A: Tobacco Use Cessation and Alcohol Consumption A Guidelines ����������������������������������������������������������������������������������������������������������  81 Appendix B: Guidelines for a Healthy Diet ����������������������������������������������������  85 Appendix C: Eruption Dates of the Teeth��������������������������������������������������������  89 Appendix D: Useful Evidence-Based Dentistry UK Websites������������������������  91 Index��������������������������������������������������������������������������������������������������������������������  93

1

Health Education

Key Points

• Oral health is multi-faceted and includes the ability to speak, smile, smell, taste, touch, chew, swallow and convey a range of emotions through facial expressions with confidence and without pain, discomfort and disease of the craniofacial complex. • Health education should be based on the best available evidence of disease causation and prevention. • Health promotion strategies should be based on what works, and interventions should be monitored, using standardised indices and long-term evaluation in order to strengthen the evidence base and improve the quality of health education. Evidence Base C.

1.1

What Is Oral Health?

In 2016, the FDI World Dental Federation, which serves as the principal representative body for 200 members of dental associations in about 130 countries, developed and approved the following definition [1]: Oral health is multi-faceted and includes the ability to speak, smile, smell, taste, touch, chew, swallow and convey a range of emotions through facial expressions with confidence and without pain, discomfort and disease of the craniofacial complex. The establishment of good oral health should begin in early childhood so that healthy growth and development are promoted throughout life. The World Health Organization (WHO Regional Office for Europe, Copenhagen, 2016) emphasises that Oral health is essential to general health and well-being and greatly influences quality of life. It is defined as a state of being free from mouth and facial pain, oral diseases and disorders that limit an individual’s capacity in biting, chewing, smiling, speaking and psychosocial well-being [2]. © Springer Nature Switzerland AG 2019 R. Levine, C. Stillman-Lowe, The Scientific Basis of Oral Health Education, BDJ Clinician’s Guides, https://doi.org/10.1007/978-3-319-98207-6_1

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Risk factors for oral diseases include an unhealthy diet, tobacco use and excessive alcohol consumption and are common risk factors for the four leading chronic diseases—cardiovascular diseases, cancer, chronic respiratory diseases and diabetes—and oral diseases are often linked to chronic disease. Poor oral hygiene is also a risk factor for oral disease. The prevalence of oral disease varies by geographical region and the availability and accessibility to oral health services, although there is evidence that access to good oral health services does not always lead to a decrease in the prevalence of oral disease. Social determinants in health and oral health are also very strong indicators of prevalence and cause major inequalities in health. This is an increasing challenge in most places in the world and also in some high-income countries and regions like Scandinavia. Worldwide the oral disease burden is significantly higher among poor and socially disadvantaged population groups. Oral health must always be considered as an integral part of general health. Not only are there a range of common risk factors that link oral disease with systemic conditions, one example being periodontitis (advanced gum disease) and type 2 diabetes (see Chap. 4), but the same health education message can address both oral health and general health. Examples being the promotion of a healthy diet, which can reduce the risk of caries, periodontal disease and erosion as well as cardiovascular disease and obesity-related illnesses and a reduction of alcohol consumption, reducing the risk of oral cancer together with other types of cancer and liver disease (see the section on common risk factors below).

1.2

What Is Health Education?

There are many definitions of health education; however, one of the most useful is an adaptation of a definition from the World Health Organization, Health education is the process by which people are given information to enable them to exercise a greater degree of control over their own health. The process of formulating and delivering health education messages includes a series of steps: • The first step is to gain an understanding of the basic cause of the disease process under consideration. Taking dental caries as an example, the basic mechanism is the conversion of sugars in the diet into acid by the bacteria in plaque biofilm on the surfaces of the teeth. • Next, it is necessary to identify the essential causative factors. Some of these will be beyond individual personal control, such as environmental factors and genetics. However, other factors may be under the control of the individual and amenable to change. In the case of caries, factors partly under personal control can include the effective use of fluoride toothpaste and reducing the frequency of consumption of sugar-containing foods, drinks and confectionary. However, where sugar-containing foods are much cheaper than fresh fruits and vegetables, it is very hard for consumers to make healthy choices.

1.3 The Common Risk Factor Approach

3

• The third stage is to agree scientifically based and socially acceptable messages for the public aimed at encouraging beneficial behavioural changes. For the prevention of dental caries and indeed a range of other diseases, one could suggest that people should never consume sugars as part of their diet. However, compliance with this message is unrealistic because sugars are present in many foods and drinks, either naturally or added artificially. A more sensible message would be: ‘consume as little sugar as possible, especially avoiding sugars sweetened foods and drinks between meals and at bedtime’.

This message can reduce the risk from tooth decay and a range of other diseases and is more likely to be accepted; however, this message may need to be modified where individuals’ eating patterns do not conform to traditional mealtimes, and there may be no regular fixed bedtime for children. • The final and possibly the most difficult stage is that of communication. This process aims to ensure that key information is conveyed comprehensibly to the right target audience, in the right context, at the right time. In line with the World Health Organization’s Ottawa Charter [3], strategic aims for health promotion include traditional methods of health education, such as giving information and advice, thereby developing personal knowledge and skills. This process can enable people and especially the younger generation to take more effective control over their own health. Health promotion also includes other elements: building public policies that support health, creating supportive environments, strengthening community action and reorientating health services. These are beyond the scope of this book, but health promotion, such as promoting public policies to support health and making healthier choices easier, is vital if health education initiatives are to be successful. The context for health education—settings for health communication: community settings include the media, life-course programmes, kindergartens, day care centres, schools, the work place, old-age care institutions/nursing homes and hospitals. Clinical settings include dental practice and community dental clinics.

1.3

The Common Risk Factor Approach

There is a growing realisation that oral health is an integral part of overall health and shares many common risk factors with leading chronic diseases, commonly referred to as non-communicable diseases (NCDs) [4]. The World Health Assembly’s resolution on oral health: action plan for promotion and integrated disease prevention urged member states to adopt measures to ensure that oral health is incorporated as appropriate into policies for the integrated prevention and treatment of chronic non-communicable disease and communicable disease, and into maternal and child health policies. Renal, oral and eye diseases pose a major health burden for many countries, and these diseases have common risk factors and can benefit from common responses to NCDs. A meeting on prevention

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and control of NCDs concluded with a political declaration that commits governments of the world to significant and sustained action to address the rising burden of NCDs such as diabetes, cancers, cardiovascular and respiratory diseases, with oral diseases as an integral part. It is appropriate because the risk factors for oral diseases are common to other major chronic diseases. Therefore there is a need to incorporate programmes for promotion of oral health and prevention of oral diseases into programmes for the integrated prevention and treatment of all major NCDs. In the last two decades, there has been an increasing awareness and evidence of inequalities in health globally. Therefore these programmes must become an essential and integral part of the drive to reduce global health inequalities in both developed and developing countries [4, 5].

1.4

Does Health Education and Promotion Work?

One of the most debated issues in public health is the effectiveness of health education and promotion. While the processes of health education and health promotion are linked and may overlap, health education can be defined as the process by which messages aimed at enabling individuals to take greater control over and improve their health are formulated. Health promotion is the process by which these messages are taken and disseminated, reinforced and their impact assessed, whether by word of mouth, in print or through one of the rapidly expanding forms of visual media, for both individuals and populations. The WHO defines health promotion as the process that extends health education beyond a focus on individual behaviour towards a wide range of social and environmental interventions. In many countries, considerable resources are spent on a range of interventions, ranging from one-toone advice in primary care settings to comprehensive healthy school schemes and mass media campaigns aimed, for example, at encouraging tobacco cessation. The strength of the evidence base for these interventions varies. A recent review of the evidence has been published in England by the National Institute for Health and Care Excellence (NICE) [6]. The report concludes that: • There is strong evidence that oral hygiene and gingival health can be improved by using psychological behaviour change models as the basis of the intervention. • There is strong evidence that patients’ knowledge levels can be improved by receiving oral health messages from an oral health practitioner. • There is strong evidence that leaflets and written material are effective in promoting patients’ knowledge, but no evidence that leaflets are effective for changing people’s behaviour. • There is strong evidence that a number of barriers and facilitators to the successful delivery of oral health promotion in the dental surgery exist. • There is moderate evidence that patient motivation and satisfaction are dependent on the oral health professionals’ communication skills and ability to build therapeutic alliances with their patients.

1.4 Does Health Education and Promotion Work?

5

• There is moderate evidence that the nature of the ‘sender’ of oral health promotion messages and their attitudes and beliefs about oral health promotion can act as either a barrier or facilitator to effectiveness. • There is weak evidence that improvements in knowledge lead to improved oral health behaviour, at least in the short term. • There is no evidence available regarding the effectiveness of linking oral health promotion messages to wider health outcomes. It is important to remember that parental health knowledge and behaviour patterns are assimilated by their children and can have a positive effect on psychological and behavioural growth. In the dental setting, the full and active involvement of the parent, child and dentist, the paediatric dentistry triangle, should be the foundation for the development of good oral health. In an age when cost benefit assumes ever greater importance in healthcare, the effectiveness of oral health promotion in terms of the reduction in disease and healthcare costs is clearly of great significance, when investing scarce resources. Common findings on the effectiveness of interventions: • Fluoride whether in toothpastes, water supplies or topical agents is an effective caries preventive agent. • An improvement in an individual’s oral health knowledge can be achieved through oral health promotion, but the long-term impact of this is not clear. • Information alone does not produce long-term behaviour changes. • General awareness can be raised by mass media campaigns, but they are not effective at promoting either knowledge nor behavioural change. • Few studies have assessed the effect on interventions on reducing oral health inequalities, but untargeted health education may increase inequalities. • Short-term changes in plaque levels can be achieved through oral health promotion interventions. These changes are not sustained over time. • Very few well-designed studies have assessed the effectiveness of interventions aiming to reduce sugar consumption. • In general, cost-effectiveness has not been assessed in oral health promotion interventions [7]. Furthermore there is little evidence for the effectiveness of screening for the early detection of oral cancers. However, there is also an ethical obligation for health professionals possessing information that could reduce the prevalence of disease to inform the public accordingly, irrespective of whether a cost benefit can be proven to follow. So efficiency as well as effectiveness of oral health interventions should be assessed. The right of individuals to health education information was clearly defined by the Ottawa Charter in 1987 [3]. Therefore, three things are clear. First is that more research is needed with the aims of improving the quality of health education delivered and evaluating the results of interventions, including their sustainability. The second is that although strong evidence for the effectiveness of health education and promotion is lacking in some areas, this does not remove from health professionals the

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responsibility to provide the public with all available information for the promotion of good health. Finally, in order to be effective, health education needs to be properly planned, organised and evaluated, using the skills of all health professionals and the best quality and most appropriate resources. We must remember that while dental professionals have had the knowledge of how to prevent dental caries or more than 50 years, it remains the most prevalent of all diseases, affecting more than 2.5 billion people globally [8].

1.5

Guidance on Oral Health Promotion

In England, the National Institute for Health and Care Excellence (NICE) has published guidance relevant to the dental team [9]. This guideline covers how general dental practice teams can convey advice about oral hygiene and the use of fluoride. It also covers diet, tobacco, smokeless tobacco and alcohol intake. The recommendations cover oral health advice given by dentists and dental care professionals and how dentists and dental care professionals can adopt a patient-centred approach. In addition, Public Health England’s Delivering better oral health: an evidencebased toolkit for prevention (third edition 2017) has been published to meet the demand of primary care dental professionals for clear guidance about the advice they should give and the actions they should take to be sure they are doing the best for their patients in preventing disease [10]. Two useful guides to one-to-one behaviour change interventions are available that are relevant to the dental team [11, 12]. The use of motivational interviewing, as a non-judgemental, non-confrontational and non-adversarial counselling method is now being advocated. This approach attempts to increase the client’s awareness of the potential problems caused, consequences experienced and risks faced as a result of the behaviour in question [12].

1.6

The Nature of Scientific Evidence

Scientific evidence comes in many forms, but in the context of oral health, it breaks down into two main categories.

1.6.1 Laboratory-Based Studies These range from purely chemical or biological observations and experiments on the structure of the teeth and the mouth to experiments involving animals or small groups of human volunteers. Examples include the analysis of the changes that occur in the teeth when they decay and studies on the effect on bacteria in the mouth when human volunteers use different types of toothpaste.

1.6 The Nature of Scientific Evidence

7

1.6.2 Clinical Studies An important type of clinical study is the interventional experiment. These studies are usually made up of at least two groups, one of which will be a control group who received no intervention, and the other groups will follow some form of experimental regime. A good example is the clinical trial of a new toothpaste. In an ideal experiment, subjects will be randomly allocated to a group, and the research workers who make the observations will have no knowledge of the group to which any subject has been allocated. This type of experiment is called a randomised controlled trial (RCT) and has often been described as the gold standard for clinical research. Clinical scientists begin with what is called a ‘null hypothesis’, which means that no difference between the test and control groups is anticipated. The experiment, be it in the test tube or in the form of a RCT, aims to blindly ‘break’ or ‘disprove’ that hypothesis.

1.6.3 Community Studies These include observational studies where existing aspects of health are studied in large groups or populations without any form of intervention. Observational studies can include longitudinal ones where a group of subjects are followed over a period of time and cross-sectional studies and case-control studies where a comparison is made with a control group. Community studies are often used in health systems analysis. While many research studies, ranging from small-scale laboratory studies to large clinical trials use quantitative methodology, where the results are obtained and expressed solely on a numerical basis, much research in the social sciences, including studies on the effect of health promotion interventions use qualitative methodology. Such studies often depend on the analysis of questionnaires completed by participants, where the outcome, which might be summarised in numerical terms, is an expression of matters concerning qualities rather than quantities. Good research studies are usually published in peer-reviewed scientific journals, including those in the clinical and public health fields. These accept only those manuscripts which have been reviewed independently and refereed by experts in the field to ensure that the methods used and the conclusions being made are valid. A very useful overview of research in any particular field is often provided by a systematic review. This is usually written by leading experts who look at all the research that has been done on a particular topic or subject, compare and contrast the results, possibly commenting on the quality of the research and draw appropriate conclusions. Evidence from comprehensive systematic reviews has come to occupy a key position between research and practice. Consequently, they have become very influential as a foundation for preventive practice and policy in dentistry. Finally, there

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is a method of comparing quantitatively the results from a number of studies that have looked at the same issue, usually in the form of randomised controlled trials. Using a sophisticated statistical analysis, the results from all of the trials are pooled together to arrive at one main result. This type of overall analysis of results is called a meta-analysis. By including a meta-analysis in a systematic review, it is possible to provide valuable insights concerning the effectiveness of healthcare interventions. One very important point must be made about the result of any scientific research, especially because of increased media reporting of health-related research and the rise of social media on the Internet. When the conclusion of a study is that there is no evidence to form a conclusion, it does not mean that the negative situation has been firmly established. It simply means that the study has not provided evidence for or against the relationship being studied. This is a point that is frequently misunderstood by those without a scientific background, who will reasonably assume that when a scientist says that there is no evidence for this or that, it means that it is not true. All the scientist is saying is that the experiment does not give sufficient evidence to draw a firm conclusion. It is possible that next week or next year evidence will appear that does establish the case.

1.7

Health Education and Evidence-Based Dentistry

From the early 1970s, there has been a growing interest in placing all aspects of clinical practice on an evidence-supported basis. One of the pioneers of this movement was Professor Archie Cochrane, who gave his name to an international collaborative network of groups with the aim of developing evidence-based decision-making for clinical interventions. The Cochrane Collaboration produces a series of systematic reviews of scientific evidence on a range of topics in all areas of healthcare, and some of these are used to support statements made in this document. A further extension of this movement is the appearance of a number of organisations and networks whose aim is to standardise and integrate the methods used for the development of guidelines for clinical practice. In the UK, one of the most useful is that developed by the Scottish Dental Clinical Effectiveness Programme. One result of this work has been to establish a framework that enables those involved in producing clinical guidelines to formulate them on a common basis. The concept of putting clinical practice on to an evidence basis has run in parallel with work to ensure that health education messages given to the public are based on sound scientific evidence. Nevertheless, an important difference between these two areas is that while the evidence for clinical interventions ideally comes from highquality clinical studies such as randomised controlled trials (RCTs), the evidence to support dental health education messages often comes from other types of studies. A system for indicating levels of evidence about the effectiveness of healthcare interventions has been developed by the Centre for Evidence-based Medicine

References

9

(CEM) levels and adopted by various evidence-based guideline organisations worldwide, and this scheme is undergoing constant refinement (http://www.cebd. org). In this book, a simple scheme is introduced to give an indication of the strength of evidence supporting key statements for dental health education and is referred to as Evidence Bases. The equivalent nearest to the Centre for Evidence-based Medicine (CEM) levels are given in brackets. • Evidence Base A: Statements supported by randomised controlled trials, metaanalyses or systematic reviews (CEM levels 1 and 2). • Evidence Base B: Statements supported by the majority of other relevant studies (CEM levels 3 and 4). • Evidence Base C: Statements that cannot be supported by a substantial body of research evidence, but where there is a consensus of scientific and professional opinion to support the statement. There may nevertheless be dissenting views, as the issue may be the subject of continuing debate and research studies (CEM level 5). Where appropriate these grades are marked as Evidence Bases A, B and C, respectively, and each would represent the highest grade of evidence that currently exists for a given statement. This way of defining the strength of evidence is best suited to research using quantitative methodology. Health education, health promotion, social determinants and inequalities in health on the other hand also develop and benefit from using qualitative methodology. Because of statistical limitations, there are few if any meta-analyses of oral health education or oral health promotion studies using qualitative methodology.

References 1. https://www.fdiworlddental.org/oral-health/fdis-definition-of-oral-health 2. http://www.euro.who.int/en/health-topics/disease-prevention/oral-health 3. World Health Organization. The Ottawa charter for health promotion. Geneva: WHO; 1986. 4. Sheiham A, Watt RG. The common risk factor approach: a rational basis for promoting oral health. Community Dent Oral Epidemiol. 2000;28(6):399–406. 5. Petersen PE. Oral health. In: Heggenhougen K, Quah S, editors. International encyclopedia of public health, vol. 4; 2008. p. 677–85. isbn:9780128036785. 6. Kay E, Hocking A, Nasser M, Nield H, Vascott D, Dorr C, Scales H. Oral health: approaches for general dental practice teams on promoting oral health. London: National Institute for Health and Care Excellence; 2015. https://www.nice.org.uk/guidance/ng30/evidence/ evidence-review-pdf-2240895421 7. Schou L, Watt RG, Fuller S, Fisher J. Oral health promotion—principles and practice. In: Pine C, Muirhead V, editors. Community oral health. Berlin: Quintessence; 2018. In Print. 8. Marcenes W, Kassebaum NJ, Bernabé E, Flaxman A, Naghavi M, Lopez A, Murray CJ. Global burden of oral conditions in 1990-2010: a systematic analysis. J Dent Res. 2013;92(7):592–7. https://doi.org/10.1177/0022034513490168.

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9. National Institute for Health and Care Excellence. Oral health promotion: general dental practice. [NG30]. London: NICE; 2015. https://www.nice.org.uk/guidance/ng30 10. Public Health England. Delivering better oral health: an evidence-based toolkit for prevention—summary guidance tables. 3rd ed. London: Public Health England; 2017. https://assets. publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/605266/ Delivering_better_oral_health.pdf 11. Mason P, Rollinick S, Butler C.  Health behavior change. 2nd ed. London: Elsevier; 2010. isbn:9780702031533 12. Ramseier CA, Suvan JE., editors. (eds)Health behavior change in the dental practice. Iowa: Wiley Blackwell; 2010. https://doi.org/10.1002/9781118786802.

2

Dental Caries

Key Points

• Caries occurs in all populations and age groups (Evidence Base A). • Caries is caused by the action of sugars on the bacterial plaque covering the teeth (Evidence Base A). • The risk of developing caries can be reduced by avoiding sugars between meals and at bedtime (Evidence Base B). • Water fluoridation is safe and effective and is the only means of caries prevention that does not require personal compliance but may be associated with an increase in mild enamel fluorosis (Evidence Base A). • The risk of developing caries can be reduced by brushing with a fluoride toothpaste at least once daily but requires compliance (Evidence Base A). • A pea-sized amount of fluoride toothpaste should be used by young children (a small smear for babies), and brushing should be supervised (Evidence Base B). • Supervised brushing of children’s teeth with a fluoride toothpaste leads to greater caries reduction (Evidence Base B). • Fluoride varnish applied twice yearly is effective in helping to prevent caries but may be unnecessary in populations with low levels of caries prevalence (Evidence Base A). • Never leave infants with sugar-sweetened drinks in feeding bottles or cups, especially at bedtime (Evidence Base B).

2.1

Who Gets Caries?

This condition is one of the most common non-communicable diseases affecting mankind. This was true for much of the Western developed world during the last century, but not for Asia and Africa. Within Western Europe and North America, © Springer Nature Switzerland AG 2019 R. Levine, C. Stillman-Lowe, The Scientific Basis of Oral Health Education, BDJ Clinician’s Guides, https://doi.org/10.1007/978-3-319-98207-6_2

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the level of caries in children appeared to reach a peak in the 1960s and has decreased in prevalence in most countries during the following 30 years. A decline in the prevalence and the severity of dental caries has been seen in countries having established community and public health services, the wide usage of fluoride toothpaste, rising living standards and access to healthcare and preventive advice. However, in some countries during the past decade, such as parts of Eastern Europe and some low- and middle-income countries, the situation has reversed, and scientific reports signal an increase in the prevalence of dental caries in children and adults, both in primary and permanent teeth [1]. While it remains a major health problem for people of all ages, its peak activity occurs during childhood. International comparisons are difficult because of variations in sampling procedure, examination methods and survey periods; however in China, Mexico and the Philippines, prevalence of more than 80% in young children has been reported. Worldwide, the WHO estimates that 60–90% of schoolchildren and nearly 100% of adults suffer from dental caries [2]. In the UK, national oral health surveys were undertaken at regular intervals by the British Association for the Study of Community Dentistry and since 2012 surveys in England have been administered by Public Health England. The 2017 survey showed continued improvement with 77% of 5-year-old children in England examined with parental consent not having experienced dental caries. Those with caries had an average of 3.4 affected teeth [3]. The average number of affected teeth in the whole sample (including those who were free of dental caries) was 0.8. The results from the 2014 Scottish survey showed 68% of 5-year-olds had no decay experience. An interesting comparison comes from the 2002 North South survey of children’s dental health in Ireland. In the Republic of Ireland where 70% of the population is supplied with artificially fluoridated water, 5-year-olds in the fluoridated areas had on average one decayed tooth. In non-fluoridated Northern Ireland, 5-years-olds had 1.8 decayed teeth. For 15-year-olds, the figures were 2.1 and 3.6, respectively [4]. There are wide variations in caries prevalence, often within small geographical areas, and this is related to several social factors. Firstly, like many other diseases, it has become apparent that a high level of dental caries is essentially a disease associated with social deprivation with family income and educational status being the determining factors, although in some developing countries the opposite may be true. In the UK, a low prevalence of dental caries can now be seen in the more affluent areas, especially in Southern England. However, levels remain high in children in many inner-city socially deprived areas of Wales, Scotland, Northern Ireland and northern parts of England. A further factor is ethnicity and is a complex one, possibly related to different dietary and toothbrushing practices within different cultures. Some children of Asian ethnic background, including children of non-English-speaking mothers, have the highest caries rates for primary teeth. One UK study of 5-year olds found that Asian children had 60% more decayed teeth than white children living in the same towns [5]. However, this difference is not apparent in the permanent teeth of older children.

2.2 How Caries Affects Teeth

2.2

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How Caries Affects Teeth

Dental caries affects the tooth itself. The consequences of caries are familiar to most people (Fig. 2.1). The process begins at the tooth surface but is often hidden from sight in the fissures (grooves) or between the teeth. Where it is visible, the initial appearance may be as a chalky white patch or ring around the neck of the tooth or as a shadow or staining on the biting surface (Fig. 2.2). The chalky appearance is due to the enamel surface having lost some of the calcium and phosphate mineral crystals of which it is largely composed. This process is called demineralisation. The destructive process can then spread into the dentine (the softer, sensitive part of the tooth beneath the enamel). The weakened enamel then collapses to form a cavity, and the tooth is progressively destroyed. Dental caries causes progressive destruction of the crowns of the teeth often accompanied by severe pain and infection. The roots of teeth can also be attacked should they become exposed by gum recession, and this is more common in older adults. Fig. 2.1  Dental caries

Fig. 2.2  Caries at the necks of teeth, from ‘white spot’ stage to cavitation

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2.3

2  Dental Caries

Cause

The basic process that causes caries is sometimes called an ‘acid attack’. Caries begins within an organic layer that forms on the surfaces of teeth, often referred to as ‘plaque’ but more correctly as a biofilm following the consumption of free sugars present in drinks and foods. The term free sugars is explained in the next chapter. • When free sugars enter the mouth, they are rapidly absorbed by the bacteria in the plaque layer on the surfaces of the teeth. • Inside the bacterial cells, the sugars are converted by metabolic processes into organic acids as a waste product and excreted into the biofilm fluid. • The acids accumulate in the plaque biofilm and cause demineralisation of the enamel surface.

Sugars ® plaque ® acid ® demineralisation

This ‘acid attack’ is more accurately described as a ‘demineralisation episode’ caused by the action of biofilm bacteria on sugars entering the mouth. Sucrose and glucose are the most important dietary sugars as they are added to many food products and beverages during manufacture. As table sugar, sucrose is often added during cooking or immediately before consumption. These simple sugars can enter the biofilm bacteria and be metabolised within minutes of being consumed. Since the biofilm covers most tooth surfaces and reforms quickly after brushing, acid forms within the plaque biofilm in contact with the teeth. Most people will consume some sugars as part of the everyday diet, but not everyone develops caries. To explain why this is so, we must look in more detail at the factors that determine the risk from dental caries. The pattern and severity of attack are determined by two groups of factors – those in the environment of the tooth, which influence the severity of the attack, and those factors that influence the tooth’s resistance to attack.

2.4

The Tooth’s Environment

The important factors within the mouth that interact to influence the severity of attack are the biofilm, dietary sugars, saliva and fluoride. Sugars from the diet pass into the biofilm within seconds of consumption. Many biofilm bacteria use sugars as their source of energy and rapidly produce acid as a by-product. As acid is generated, it accumulates in the plaque biofilm, and acidity increases. Acidity is measured on the pH scale, and the lower the figure, the greater the degree of acidity. Figure 2.3 shows the effect of a sugar intake on plaque pH. The fall in plaque biofilm pH when sugars enter the mouth and the subsequent recovery as shown in the diagram is called the ‘Stephan curve’. This demineralisation-remineralisation episode is sometimes referred to as an ‘acid attack’. Within minutes of sugar intake, sufficient acid may be generated within the absorbent plaque biofilm layer to cause a small outflow of calcium and phosphate from the enamel resulting in a tiny degree of demineralisation. After a

2.4 The Tooth’s Environment

15

Sugar intake 7

remineralisation

pH 5

demineralisation 0

20 Time (min)

40

Fig. 2.3  The effect of sugar intake on plaque biofilm pH

a pH

Sugar intakes

7

remineralisation

5 demineralisation 0600

b

pH

1200 Time (hrs)

1800

2400

Sugar intakes

7

remineralisation

5 demineralisation 0600

1200

1800

2400

Time (hrs)

Fig. 2.4  Effect of (a) frequent sugar intakes (b) infrequent sugar intakes

period of time (usually about 20 min but possibly up to 2 h), the acid will have dissipated, and the lost mineral may be slowly replaced from the saliva. This process is called remineralisation. However, if sugars are consumed frequently during the day, especially without the presence of other food or liquids that might dilute or help neutralise the acid, then the amount of demineralisation may exceed remineralisation. This situation is illustrated in Fig. 2.4a where a frequent intake of sugars during the day leads to an unfavourable proportion of total demineralisation to remineralisation periods, while an infrequent sugar intake results in a more favourable proportion as seen in Fig. 2.4b. If this imbalance persists over a period of time, then the gradual loss of mineral from the enamel may lead to its eventual breakdown and the formation of a cavity [6]. The type of bacteria that predominate within the biofilm is influenced by the diet. Frequent consumption of sugars has been shown to encourage the multiplication of bacteria that use sugars and can efficiently convert them to acid, and it also increases the thickness of the plaque biofilm layer. The most commonly implicated biofilm organisms are Streptococcus mutans and Lactobacillus acidophilus; however there are many other types that metabolise sugars to form acid, which together with others

16

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form a related microbiological complex. If the plaque biofilm is left undisturbed and allowed to mature, the nature of the biofilm complex changes, as described below. The proportion of these caries-causing bacteria falls when the amount and frequency of dietary sugars are reduced. However, the mouth has its own defence mechanisms. While these are not fully understood, saliva is clearly the most important as it bathes the plaque on the tooth surface and helps to neutralise the acids and wash away sugars. This effect is enhanced if salivary flow after sugary snacks is stimulated, for example, by vegetables, cheese or sugar-free chewing gum. In addition, at the very earliest stages of the decay process, the tooth surface may ‘heal’ or ‘remineralise’ by deposition from saliva of calcium and phosphate, together with fluoride, which accelerates the healing process. The early caries process may be seen as a contest fought at the tooth surface between the acids (resulting from the intake of sugars) causing demineralisation of the tooth surface and a number of factors including fluoride and saliva promoting the remineralisation of the tooth surface. It is now well established that the plaque biofilm matures as it is left to grow within the mouth. Moments after the teeth are brushed, a layer of protein, called the pellicle, forms. The tooth becomes covered in protein, and within minutes plaque bacteria can begin to colonise the pellicle. With time, the plaque becomes thicker and will contain a more diverse colony of many bacteria. Particularly if the diet is rich in sugars, the plaque grows and reaches its most mature at about 7 days. Plaque of this age will break down the sugars extremely quickly, again putting the mineral component of the tooth in danger of becoming demineralised. This mature plaque layer is often referred to as a ‘biofilm’ since it can be made of several hundred types of bacteria that will change in type from the tooth surface to the outer surface of the plaque.

2.5

Diet

2.5.1 Sugars in Our Diet While there are several dietary free sugars that have been linked to caries, sucrose is the most important. The term free sugars is explained in the next chapter. Food industry statistics estimate that almost half of the sucrose consumed by the public is sold as packaged sugar and about half is used by food, drink and confectionery manufacturers. The major industrial use of sucrose is the production of confectionery, which accounts for about a quarter of the total used in manufacturing, while the soft drinks industry uses about one fifth. Nearly three-quarters of all sugars in the UK diet are added to foods during manufacture, cooking or before consumption. Confectionery, soft drinks, cakes, biscuits and table sugar (e.g. in tea and coffee) are often consumed between meals, and their frequent consumption is strongly linked to dental caries. The other sugars in the diet are naturally present in foods such as whole fruit, vegetables and milk. When sugars are consumed as part of these foods, they are considered to be relatively unimportant as a cause of decay.

2.5 Diet

17

2.5.2 Dietary Advice Dietary advice should be aimed at changing the pattern of consumption of free sugars with the aim of reducing the amount of consumption helped by a reduction in frequency of intake. Food and drinks containing free sugars should be identified and restricted, especially between meals. While fresh fruits and vegetables naturally contain sugars, their consumption as part of a normal diet is not linked to caries, and they have an important place in our diet. People should be encouraged to eat snacks that are sugar-free (e.g. carrots, peppers, breadsticks, savoury sandwiches and cheese). Fresh fruit is a really important part of the diet; however fruit juice, smoothies and dried fruit can adversely affect teeth because of their high concentration of sugars and acid and are not recommended for consumption between meals. Concentrated fruit juices and cordials should be well diluted with water. Plain water and milk are the safest drink as far as the teeth are concerned. Parents and carers of infants should be warned of the dangers of putting fruit juice or sugar-sweetened drinks into feeding bottles and valve-type or reservoir feeders for the child to hold, especially in bed. Such practices result in almost continuous bathing of the enamel with sugars and can lead to rapid tooth destruction. From 6 months of age, infants should be introduced to drinking from a cup. Freeflow lidded feeding cups can help avoid spills in the early stages, before infants move on to an open beaker or cup. Feeding bottles should be discouraged after the age of 12 months. People should also be encouraged to study the nutritional labels of food and drinks and avoid frequently consuming those with high levels of sugars such as those containing more than 10 g per 100 g. Foods and drinks may contain added sugars other than sucrose. The ingredient of greatest amount is always listed first, and the words used to describe sugars include glucose, maltose, fructose, hydrolysed starch, invert sugar, corn syrup and honey (when listed as an added sugar). They are as likely as sucrose to cause caries and should not be used in infant drinks and foods unless they are consumed only at mealtimes. If one of these is near the top of the list of ingredients, the food or drink is likely to be high in sugars. The use of sugars in medicines should also be strongly discouraged, and sugarfree liquid medicines should be chosen by prescribers and when buying non-prescription medicines, whenever possible. If children have a long-term medical condition, parents and carers should request clinicians to prescribe sugar-free liquid medicines or, preferably, tablets instead of liquids.

2.5.3 P  referable Snacks and Drinks for Between-Meal Consumption For between-meal snacks and drinks, raw unprocessed vegetables such as carrots, fresh fruit, brown or wholemeal bread, low-fat unsweetened yoghurt, lower-fat cheese, skimmed or semi-skimmed milk and water can be recommended. Whole cow’s milk should only be used as a main milk drink after the age of 1 year. Children

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between 1 and 2 years of age need whole milk. Between the ages of 2 and 5 years, provided they are eating a good varied diet, semi-skimmed milk can be introduced. Fully skimmed milk should not be given before the age of 5. Milk and water are the only safe drinks for the teeth. Fruit juices contain sugars and acids, so it’s best to have these only at mealtimes. Fruit juice should be diluted with ten parts of water to one of juice. Babies under 6 months should not be given fruit juices or cordials. More information on diet and caries can be found in Chap. 3.

2.6

The Tooth’s Resistance

Largely because of their shape or position in the mouth, some teeth are more resistant to attack than others. For example, in young people lower front teeth rarely decay because they don’t have any grooves or fissures in which plaque can stagnate and they are bathed by saliva, which is beneficial. In contrast, the first permanent molar teeth have the highest decay rate because the deep fissures on the biting surfaces are difficult to clean. The one factor that has been shown beyond doubt to reduce the rate of dental caries is fluoride, and this is described below. In the UK, neither malnutrition in the mother during pregnancy nor in the child after birth is likely to have any appreciable effect on the susceptibility of the teeth to caries. Calcium cannot be removed from the mother’s teeth by the foetus during pregnancy or during lactation.

2.7

Prevention

There are two principal ways for individuals to reduce the risk of caries. The first is to reduce the severity of attack by decreasing the amount and frequency of consumption of sugars as described above and in Chap. 3. The second way is by using fluoride, which is easily and effectively done by brushing twice daily with a fluoride-containing toothpaste. These methods should be used together in order to improve and maintain oral health, especially for those deemed to be at high risk, an example being workers in a Danish chocolate factory [7].

2.8

Fluoride

2.8.1 Fluoride Toothpaste Fluoride toothpaste, which came into general use in the USA in the 1950s and most developed countries including Europe and the UK in the early 1970s, is now recognised as a development of the greatest importance to dental health [8]. It is thought to be the most cost-effective topical fluoride agent for personal use and is likely to be the main reason for the decline in caries prevalence in Europe and most developed countries during the last 30 years. The daily use of a fluoride toothpaste

2.8 Fluoride

19

containing at least 1000 parts per million (ppm) fluoride is a highly effective method of delivering fluoride to the tooth surface, and to some extent its use has removed the need for professionally applied fluoride agents, except in special circumstances [9]. There is good evidence that the effectiveness of brushing with a fluoride toothpaste increases with frequency of use [10], with twice-daily use giving increased benefit. Although twice daily is generally recommended, there is no evidence to support this as the optimal frequency. However, a consensus of opinion is that more frequent use by children can increase the risk of dental fluorosis (see below). In many countries fluoride toothpastes are currently available in two concentration ranges: Standard pastes containing about 1000–1500 ppm and high concentration pastes containing over 2000  ppm (see below). Low-fluoride formulations containing 500–600  ppm were introduced to meet the concern that young children might ingest excessive fluoride. Research has shown that the effectiveness of fluoride toothpastes increases with the fluoride concentration and there is no clear evidence that pastes containing less than 1000 ppm are effective; however the use of higherconcentration fluoride toothpastes by children has been associated with an increase in enamel fluorosis. The Department of Health in England now advises that children under 3 years of age should use a toothpaste containing at least 1000 ppm but that only a thin smear of paste (equivalent to half a pea size) be applied on the brush. Similar advice is given by the WHO and the American Association of Pediatric Dentists. For maximum benefit children aged 3 years and older and adults should use a toothpaste containing 1350–1500  ppm, but these standard pastes should not be used by children who might eat or swallow the paste. For children from 3 to 6 years of age, care should be taken to apply only a pea-sized amount, and parents must ensure that children do not eat or lick fluoride toothpaste from the tube. Parents should supervise and finish off the brushing to ensure that an appropriate amount of toothpaste is applied and that the child does not ingest the toothpaste. There is substantial evidence that the supervision of toothbrushing, both in school and community settings, results in a decrease in caries increment and can be of lasting benefit after supervision ceases [10, 11, 12]. In many countries the labelling of toothpastes remains unsatisfactory as the total fluoride content is not clearly marked in a simple form for the public to recognise. While brands with similar fluoride concentrations may be equally effective, other components of the formulation may influence overall benefit. A number of leading brands have been independently evaluated in published long-term clinical trials in order to ensure efficacy. There is evidence that rinsing with water immediately after brushing with fluoride toothpaste reduces the benefit both in relation to the development of new cavities and the prevention of recurrent caries around fillings. It is preferable simply to spit out the excess paste. When fluoride drops or tablets are used (see below), they should be given at a different time of day to brushing and rinsing with a fluoride mouth rinse if used.

20

2.9

2  Dental Caries

Water Fluoridation

Fluorides are compounds of the chemical element fluorine. They are widely found in nature, in some foods such as fish (bones), in some plants such as tea, in beer and in some natural water supplies. The link between the presence of fluoride in public water supplies, enamel mottling (fluorosis) and reduced caries experience was first noticed early in the last century and has been demonstrated by over 130 surveys in more than 20 countries including the UK. These surveys showed that fluoride in the water at a concentration of about one part per million (1 ppm) reduces caries levels by up to half compared to similar non-fluoride areas. In 1945, Grand Rapids in the USA became the first community to have its water supply artificially adjusted to contain 1 ppm fluoride. Since then many cities around the world have followed, the largest schemes in the UK being in Birmingham, including parts of the West Midlands and Newcastle upon Tyne. Worldwide, about 370 million people, 5% of the world population are supplied with artificially fluoridated water – an increase of 20 million people over the past 10  years and 25 countries operate fluoridation schemes, ranging from those in Hong Kong and Singapore which reach 100% of the population to 4% of the population in Vietnam. Over 80% of the population of Australia, 75% in Malaysia, 64% in the USA, 73% in the Republic of Ireland and 70% in Israel benefit from water fluoridation. Since the 1950s Brazil has had an extensive water fluoridation programme. However in the European Union only four countries provide fluoridated water, some have discontinued fluoridation for various reasons and France did not undertake water fluoridation. In addition, an estimated 50 million people drink water whose naturally occurring fluoride is at the optimum concentration. The safety of water fluoridation is well documented. Numerous studies in both natural and artificially fluoridated areas have failed to show any adverse effect on general health at the level of 1 ppm, although fluoridation may be associated with an increase in enamel fluorosis. One of the most authoritative reports is that of the Royal College of Physicians of England (1976). Fluoride’s effectiveness and safety were upheld in the Court of Session judgement in Edinburgh in 1983. In 2011 a report by the EU Commission’s Scientific Committee on Health and Environmental Risks (SCHER) concluded on the basis of the latest available evidence that ‘exposure of environmental organisms to the levels of fluoride used for fluoridation of drinking water is not expected to lead to unacceptable risks to the environment’. At an international level, water fluoridation is supported by the World Health Organization (WHO), the Fédération Dentaire Internationale (FDI) and the International Association for Dental Research (IADR) as a safe and effective means of reducing tooth dental caries. The US Centers for Disease Control and Prevention has recognised fluoridation as one of ten great public health achievements of the twentieth century, and the American Dental Association and the US Surgeon General have reaffirmed their support for water fluoridation (2013). Within the UK, water fluoridation has been embodied in guidance documents from the UK Department of Health, including An Oral Health Strategy for England (1994) and Modernising NHS Dentistry – Implementing the NHS Plan (2000). It was

2.9 Water Fluoridation

21

supported by the UK All-Party Parliamentary Primary Care and Public Health Group (2003), and in England and Wales, it is embodied in the Water Act 2004. UK professional bodies supporting water fluoridation include the Royal Society of Public Health, the Royal College of Physicians, the British Medical Association, the British Dental Association and the Medical Research Council. A systematic review of water fluoridation by the Centre for Research Dissemination at the University of York (2000) provides a comprehensive review of the knowledge base in this area. It concluded that water fluoridation reduces dental caries incidence by an average of 15% and that caries prevalence increases following withdrawal of water fluoridation. While water fluoridation was found to reduce inequalities between social groups, by reducing the differences in caries severity among 5- and 12-year-old children, there was evidence for a slight increase in dental fluorosis levels. Finally, the review found no clear associations between water fluoridation and systemic morbidity. A review by the American Cancer Society concluded that ‘The general consensus among the reviews done to date is that there is no strong evidence of a link between water fluoridation and cancer. However, several of the reviews noted that further studies are needed to clarify the possible link’. A summary of the international evidence supporting water fluoridation is available from the British Fluoridation Society [13]. An analysis of the reduction in treatment need after fluoridation has shown savings in manpower and resources. A large fall in the numbers of extractions and general anaesthetics administered to children has been reported by Public Health England in their 2014 health monitoring report. Furthermore, there is evidence from Scotland that the discontinuation of water fluoridation can result in a return to higher caries levels, despite the benefit of fluoride toothpaste. A 25% increase in caries prevalence was recorded 5  years after parts of Scotland were de-fluoridated. However, in some countries no change in caries levels has been seen when water fluoridation has ceased [14]. This might be due to changes in diet or the increased use of fluoride toothpaste. While in some areas falling caries prevalence has reduced the absolute benefit to be gained from water fluoridation, in communities where prevalence remains high, often because of social and economic factors, there are significant potential benefits. Because of these changes, the consensus of expert opinion is that water fluoridation should be targeted at areas with higher caries levels. It must be emphasised that water fluoridation is the only means of caries prevention that does not require personal compliance. While 1.0 ppm of fluoride was regarded as the optimum level, in the USA from 2015, the optimum level has been reduced to 0.7 ppm because of concern that increasing use of topical fluoride agents and treatments could increase the risk of dental fluorosis, although the scientific basis for this move has been questioned [15]. In Australia the fluoride concentration in most community water supplies is adjusted to between 0.6 and 1.1 ppm, according to local conditions. While water fluoridation has been introduced in countries with established and reasonably well-defined water distribution systems in temperate climates zones, in countries with higher average temperatures, such as equatorial countries, the average water consumption can be higher, and the water fluoride concentration must reflect this to avoid fluoride intake beyond the optimal level, as has been done in parts of Australia.

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2.9.1 Other Fluoride Agents In some countries, such as in Scandinavia where caries prevalence is very low, the additional use of other fluoride agents may not be required; however where additional protection is indicated for erupted teeth, other fluoride-containing agents are effective.

2.9.1.1 High-Fluoride-Concentration Toothpastes These are available in many countries in a variety of fluoride concentrations up to 5000 ppm. While intended for self-applied home use, in most countries, they are only available on prescription from a health professional, and care should be taken to follow the product instructions, especially when used by children, to avoid excessive ingestion. 2.9.1.2 Fluoride Varnishes These are for professional application to erupted teeth by dentists, therapists, hygienists or trained dental nurses. Typically they contain 22,600 ppm of fluoride in a sticky varnish that is applied to the surfaces of teeth using a small micro-brush once every 3–6 months. A systematic review has shown them to be highly effective for the prevention of caries [16]. As there have been some reports of allergic reactions, typically where there is a history of asthma or allergies to some medications or nuts, it is advisable that a careful medical history is obtained before use. The Department of Health in England recommends that all children over the age of 3 have a fluoride varnish application every 6 months or more frequently if indicated. Similar advice is given by the WHO and is an accepted policy in many countries. 2.9.1.3 Fluoride Mouth Rinses Fluoride mouth rinses are readily available for home use in most countries and have proved effective and convenient. A systematic review of the combined results of 13 clinical trials of supervised use by children and adolescents showed a reduction in caries of 23% [17]. This benefit is likely to persist even when fluoride toothpaste is used. While the normal fluoride concentration is 250  ppm, higher-concentration mouth rinses of up to 5000 ppm are available in some countries by prescription only. They should be used once or twice daily, only once for the high-fluoride rinses and at a different time of day to toothbrushing and not just before food or drink to maximise benefit; however they are not advised for children under 6 years of age. Like standard toothpaste they provide fluoride to saliva and plaque biofilm on tooth surfaces and invoke the first two, and most important, fluoride mechanisms described below. These agents are of greatest value for children at risk to caries and adults suffering from a dry mouth, medically compromised individuals and those undergoing orthodontic treatment.

2.9.2 Fluoride Tablets and Drops These were originally introduced to mimic the effect of water fluoridation. A systematic review found that the use of fluoride supplements was associated with a

2.9 Water Fluoridation

23

24% caries reduction in permanent teeth, but the effect on primary teeth was unclear.. When the fluoride supplements were compared with the use of topically applied fluorides such as toothpastes, varnishes and mouth rinses, there was no differential effect on permanent or deciduous teeth. For maximum effectiveness, daily administration from infancy until adolescence was required, although compliance with this regime was recognised as a frequent problem. Fluoride drops and tablets are available on prescription from dentists and doctors in the many countries and may be purchased from pharmacists without a prescription. While initially seen as a potential public health measure, the introduction of fluoride toothpaste in the early 1970s has proved to be far more effective. Some experts now doubt the extent of any additional benefit that their use may provide beyond that achieved by effective twice-daily toothbrushing with a fluoride toothpaste. Today, their use should be confined to those at very high risk of caries or to those for whom dental treatment may be complicated by their general or physical condition [18]. These groups include children with heart disease or cardiac defects as well as children prone to infection because of systemic disorders. Children with special needs may be more at risk of dental disease because of oral hygiene and dietary problems and may find dental treatment, when needed, difficult or frightening. All of these children could benefit from fluoride supplements. The need for their use should be determined with dental advice and reviewed at intervals. In areas with high caries prevalence, a dosage regimen should be used that takes into account the age of the child and fluoride exposure including the fluoride content of the drinking water. Only one systemic fluoride measure should be used at any one time in a community or on an individual basis unless the child is at high risk for dental caries. Parents and carers should be advised of the benefits, and risks and especially of the long-term commitment, to the use of this measure and of the importance of safe storage away from the reach of children. A stop-start pattern of use is unlikely to provide significant benefit. The main problem with the use of fluoride dietary supplements is compliance with the required daily regime over the whole period of tooth formation. However compliance is likely to be higher in motivated families where the children may have a lower risk of developing caries, while conversely, compliance may be poorer in areas of social deprivation where the caries risk and the need for preventive measures may be greater. Some clinicians prefer to rely on professionally applied topical fluoride agents such as fluoride varnishes or gels where additional measures are required, not because of compliance issues alone. Fluoride drops or tablets should not be given in areas that have the optimum level of fluoride in the water supply, and parents should therefore seek professional advice before use. Fluoride supplements should be given daily, but the dose must not be increased if days are missed. It is generally advised that for maximum benefit, supplement use should be continued until the appearance of the second molar teeth, usually at about 11–12 years of age. However, this advice is based on the pre-eruptive effect of the ingested fluoride. Some experts believe that by allowing the tablets to dissolve slowly in the mouth, a topical post-eruptive effect may be achieved, as well as the systemic benefit, both for older children and adults who may be at risk of dental caries.

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2.10 Fluoridated Milk The use of fluoridated milk for dental caries prevention was first proposed in the 1950s, and school-based fluoridated milk programmes are now operating in five countries ranging from Russia to Chile where 220,000 children benefit. In the UK over 30,000 children in over 500 schools drink fluoridated milk at school. This is part of a programme that began in 1993 and was established under the direction of the School of Dental Sciences, University of Liverpool, UK. An additional potential benefit is that fluoridated milk may help displace sweetened soft drinks from the refrigerated vending machines found in many schools. UK studies suggest that at the level 0.5 mg F per 189 mL of milk, there is limited effectiveness, and the greatest effect is seen in the permanent dentition, and a systematic review concluded that due to the general lack of randomised evidence, more research of good methodological quality is needed [19]. However, in a recent study in Bulgaria, which like most of Eastern Europe is faced with a high burden of dental disease, a clear benefit was found [20]. The organisation and maintenance of school-based programmes can pose problems where there is high absenteeism in infant and primary schools or difficulty with the reliability of the milk distribution process.

2.11 Enamel Fluorosis This condition presents as opaque, white or brown areas, lines or flecks in the enamel surface that are most noticeable when they occur on front teeth. While these opacities can be due to a number of causes, one is the ingestion of excessive fluoride during the period of enamel formation. For incisor teeth, the period of greatest risk is between 15 and 30 months of age. The more severe, cosmetically unacceptable forms are uncommon in the UK but may result from the use of fluoride dietary supplements in optimally fluoridated areas or from eating of fluoride toothpaste in early childhood. The use of fluoride toothpaste in areas with optimally fluoridated water supplies has been shown by surveys using sensitive photographic recording to result in only a small increase in the mildest forms, which mostly pass unnoticed [21]. No increase in moderate or severe forms has yet been detected, and simple techniques are available to improve the appearance of affected teeth [22]. Nevertheless, this is an area of concern to both the public and the dental professions, and care should be taken to ensure that young children do not ingest excessive amounts of fluoride toothpaste, especially in fluoridated areas or when fluoride supplements are used. While manufacturers rightly endeavour to make the taste of children’s toothpaste attractive, there is a concern that the use of food flavouring such as strawberry may encourage excessive consumption. To reduce the risk of fluorosis, parents should supervise toothbrushing of children under 7 years of age and should place an amount of toothpaste no greater than the size of a pea on the brush (or a small smear for babies). Brushing should be done normally no more than twice each day, and the child should be encouraged to spit out afterwards rather then rinse with water. Supervision will continue to be

2.13 How Does Fluoride Work?

25

beneficial beyond this age. When fluoride drops or tablets are used, they should be given at a different time of the day to brushing. Two recent reviews provide more information on all of the above aspects of the use of fluoride for caries prevention [23, 24].

2.12 Systemic Fluorosis While artificial water fluoridation is safe, excessive fluoride intake can have detrimental effects, and in parts of the world where greatly increased intake from fluoride naturally present in the available water supply or as a result of environmental factors or industrial activity, more severe dental and skeletal changes can occur [25]. Seawater typically contains 1.5 ppm of fluoride, while groundwater with high fluoride concentrations occur extensively across wide geographical areas, including parts of Asia, the Indian subcontinent and southern parts of the USA, Southern Europe and the former Soviet republics. The best example is the East African rift system from the Jordan Valley and down through East Africa, with parts of Kenya having groundwater fluoride concentrations of 30–50 ppm. In rural areas in these regions and elsewhere, where most drinking water comes from boreholes or wells with high fluoride levels, severe forms of dental fluorosis and crippling skeletal fluorosis are prevalent. Fluoride can also enter the environment from industrial activity, such as mining and burning of high-fluoride-content coal deposits in parts of north-western China. Because of these considerations, it is important to consider climatic conditions, the volume of water intake and other factors when setting national standards for fluoride intake [26]. While the removal of excessive levels of fluoride in drinking water is clearly desirable and there are many methods that have been used both on domestic and industrial scales, the cost and complexity of most methods are high. Nevertheless a number of simple and effective schemes have been introduced, such as the clay column method used in Sri Lanka [26].

2.13 How Does Fluoride Work? Teeth and bone are composed largely of a crystalline mineral compound of calcium and phosphate called hydroxyapatite. Research over the past 60 years has shown that fluoride produces its effect in a number of different ways which combine to slow and help prevent the caries process and also to reverse caries in its early stages [27]. These are given below in the order of effectiveness. • Enhanced remineralisation: Very low levels of fluoride in the plaque and saliva are able to alter the chemical balance between demineralisation of the enamel and remineralisation. The effect favours the remineralisation process, allowing the early carious attack on enamel to be reversed and new mineral crystals, with better structure and greater acid resistance, to be deposited. This is the

26

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mechanism by which fluoride toothpaste is thought to work and appears to be the most important. • Reduced acid production: Fluoride is concentrated in the plaque biofilm layer on the surfaces of the teeth and reduces the conversion of dietary sugars into acid by plaque bacteria. Fluoride toothpaste also invokes this mechanism. • Fluoride substitution: Fluoride entering the developing teeth from the diet via the bloodstream is incorporated into the new mineral crystals. The partly fluoridated hydroxyapatite that is formed is theoretically more resistant to acid attack than that formed without fluoride. • Reduced pit and fissure depth: The parts of the teeth most susceptible to caries are the natural pits and grooves or fissures on the biting surfaces of back teeth. Fluoride entering the developing teeth at an early stage appears to result in reduced pit and fissure depth. The use of fluoride toothpaste, which delivers its effect at the tooth surface, has reduced the significance of the last two mechanisms, which are now thought to play a very minor role if any.

2.14 Plaque (Biofilm) Control Dental caries cannot develop without the presence of bacteria in the plaque biofilm, which are needed to convert dietary sugars into acid. Some research studies have shown that highly efficient toothbrushing techniques with professional guidance can reduce dental caries. However research has shown that normal “real-world” toothbrushing alone does not appear to be as effective. Some plaque is left in fissures and other stagnation sites where caries occurs and plaque reforms rapidly on cleaned tooth surfaces. The use of a fluoride toothpaste is firmly established as the most effective personal means for caries prevention as brushing with a fluoride toothpaste delivers fluoride to the teeth and is the main role of toothbrushing for caries prevention. Nevertheless, the value of effective toothbrushing as the essential means for the prevention of periodontal disease is well established (see Chap. 4). Toothbrushing advice for adults is given in Chap. 5 and for children in Chaps. 5 and 9. Eating crisp or crunchy foods such as apples or raw carrots will not remove plaque effectively. However they are suitable snack foods and are an important part of a healthy diet. More information on plaque control can be found in Chap. 5.

2.15 Fissure Sealants A further way of helping to prevent dental caries is for a plastic film to be professionally applied to the pits and fissures of teeth as soon as possible after the teeth erupt into the mouth. For the permanent molar teeth, this is from the age of 6 years with the eruption of the first permanent molar. The sealant prevents access of plaque and plaque acids to the enamel surface. Clinical trials have shown that sealants can

References

27

be well retained and prevent caries [28]. However, they are only effective on the biting surfaces of teeth. They are more cost-effective in children at higher risk of caries and should be considered when there is a risk to general health from dental caries or dental treatment. In all cases fissure sealants should be seen as one part of a comprehensive preventive plan.

References 1. Petersen PE. Oral health. In: Heggenhougen K, Quah S, editors. International encyclopedia of public health, vol. 4. San Diego: Academic Press; 2008. ISBN: 9780128036785. 2. WHO. Global oral health data bank. Geneva: WHO; 2017. 3. Public Health England. National dental epidemiology programme for England: oral health survey of five-year-old children. London: Public Health England; 2017. 4. Whelton H, Crowley E, O’Mullane D, Harding M, Guiney H, Cronin M, Flannery E, Kelleher V. North south survey of children’s oral health in Ireland. Dublin: Department of Health and Children; 2002. 5. Pitts NB, Pine C, Burnside G, Craven R. Inequalities in dental health in the North-West of England. Community Dent Health. 2003;20:53–4. 6. Levine RS.  The aetiology of dental caries—an outline of current thought. Int Dent J. 1977;27:341–8. 7. Petersen PE. Dental health among workers at a Danish chocolate factory. Community Dent Oral Epidemiol. 1983;11:337–41. 8. Marinho VC, Higgins JP, Sheiham A, Logan S. Fluoride toothpastes for preventing dental caries in children and adolescents. Cochrane Database Syst Rev. 2003;(1):CD002278. https://doi. org/10.1002/14651858.CD002278. 9. Walsh T, Worthington HV, Glenny AM, Appelbe P, Marinho VC, Shi X. Fluoride toothpastes of different concentrations for preventing dental caries in children and adolescents. Cochrane Database Syst Rev. 2010;(1):CD007868. https://doi.org/10.1002/14651858.CD007868. 10. Kumar S, Tadakamadia J, Johnson NW.  Effect of toothbrushing frequency on inci dence and increment of dental caries: a systematic review and meta-analysis. J Dent Res. 2016;95(11):1230–6. https://doi.org/10.1177/0022034512470690. 11. Macpherson LM, et  al. National supervised toothbrushing program and dental decay in Scotland. J Dent Res. 2013;92(2):109–13. https://doi.org/10.1177/0022034512470690. 12. Pine CM, et al. Caries prevalence four years after the end of a randomised controlled trial. Caries Res. 2007;41(6):431–6. https://doi.org/10.1159/000104800. 13. The British Fluoridation Society. One in a million. Oldham: The British Fluoridation Society; 2013. ISBN: 0-9547684-0-X 14. McLaren L, Singhal S. Does cessation of community water fluoridation lead to an increase in tooth decay? A systematic review of published studies. J Epidemiol Community Health. 2016;70:934–40. https://doi.org/10.1136/jech-2015-206502. 15. Spencer AJ, Do LG. Caution needed in altering the ‘optimum’ fluoride concentration in drinking water. Community Dent Oral Epidemiol. 2016;44(2):101–8. https://doi.org/10.1111/ cdoe.12205. 16. Marinho VC, Worthington HV, Walsh T, Clarkson JE. Fluoride varnishes for preventing dental caries in children and adolescents. Cochrane Database Syst Rev. 2013;7:CD002279. 17. Marinho VC, Chong L, Worthington HV, Walsh T. Fluoride mouth rinses for preventing dental caries in children and adolescents. Cochrane Database Syst Rev. 2016;(7):CD002284. https:// doi.org/10.1002/14651858.CD002284.pub2. 18. Rozier RG, et al. Evidence-based clinical recommendations on the prescription of dietary fluoride supplements for caries prevention: a report of the American Dental Association Council on Scientific Affairs. J Am Dent Assoc. 2010;141(12):1480–9.

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19. Yeung A, Hitchings JL, Macfarlane TV, Threlfall A, Tickle M, Glenny A. Fluoridated milk for preventing dental caries. Cochrane Database Syst Rev. 2005;(3):CD003876. https://doi. org/10.1002/14651858.CD003876.pub4. 20. Petersen PE, Kwan S, Ogawa H. Long term evaluation of the clinical effectiveness of community milk fluoridation in Bulgaria. Community Dent Health. 2015;32:199–203. 21. Levine RS, Beal JF, Flemming CM. A photographically recorded assessment of enamel hypoplasia in fluoridated and non-fluoridated areas of England. Br Dent J. 1989;166:249–52. 22. Pretty IA, et al. Prevalence and severity of dental fluorosis in four English cities. Community Dent Health. 2016;33:292–6. https://doi.org/10.1922/CDH_3930Pretty05. 23. O’Mullane DM, et al. Fluoride and oral health. Community Dent Health. 2016;33:69–99. 24. Petersen PE, Ogawa H.  Prevention of dental caries through the use of fluoride—the WHO approach. Community Dent Health. 2016;33:66–8. 25. Fawell J, Bailey K, Chilton J, Dahi E, Fewtrell L, Magara Y.  Fluoride in drinking-water. London: IWA Publishing; 2006. ISBN:1900222965 26. WHO. Guidelines for drinking-water quality. Volume 1. Recommendations. 3rd ed. Geneva: World Health Organization; 2004. 27. Levine RS. The action of fluoride in caries prevention. Br Dent J. 1976;140:9–14. 28. Ahovuo-Saloranta A, Forss H, Walsh T, Hiiri A, Nordblad A, Mäkelä M, Worthington HV. Sealants for preventing dental decay in the permanent teeth. Cochrane Database Syst Rev. 2013;3:CD001830. https://doi.org/10.1002/14651858.CD001830.pub4.

3

Diet and Oral Health

Key Points

• The amount of consumption of free sugars is the most important risk factor for both oral and general health (Evidence Base A). • One way to reduce the amount of free sugar consumption is to reduce the frequency of intake (Evidence Base C). • Sugar-sweetened snacks and drinks should be avoided between meals, including at bedtime (Evidence Base B). • Naturally occurring sugars, when consumed in fresh whole fruit, vegetables, milk and milk products and cereal grains, are not a risk factor for dental caries, and these items make an important contribution to a healthy balanced diet (Evidence Base B).

3.1

Sugars and Dental Caries

Sugars are carbohydrates, technically termed mono and disaccharides. Other carbohydrates found in the diet are mostly types of starch such as in potatoes and bread and oligosaccharides such as glucose polymers and fibre. The evidence for a link between sugars and caries comes from a variety of sources, including systematic reviews, which are the strongest source of evidence. Epidemiological studies have demonstrated a clear association between caries experience and mean sugar consumption levels in different countries [1]. The best evidence comes from systematic reviews that identify, collate and appraise evidence from a body of studies. Studies that measure change in dental caries levels over time, i.e. cohort studies, are the best available evidence to appraise in this way. In one systematic review, seven of eight cohort studies found that caries increased with increased free sugar intake [1]. Groups having low or restricted sugar consumption and those with high consumption of sugars show corresponding lower or higher levels of caries experience, © Springer Nature Switzerland AG 2019 R. Levine, C. Stillman-Lowe, The Scientific Basis of Oral Health Education, BDJ Clinician’s Guides, https://doi.org/10.1007/978-3-319-98207-6_3

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respectively. In children using sugar-sweetened medicines over long periods, higher dental caries levels have been found compared to a control group. Human non-randomised clinical studies have demonstrated that when sugars consumption is increased under controlled conditions, the caries increment follows, and it falls when consumption is reduced. Laboratory studies have demonstrated, by the use of miniature pH electrodes inserted into the plaque on teeth, an immediate fall in pH on the application of a neutral sugar solution, with the acidity persisting for 20 min to 2 h.

3.2

Sugars in Food and Drinks

The sugars most responsible for dental caries were classified by the UK Committee on Medical Aspects of Food Policy (COMA, now SACN the UK Scientific Advisory Committee on Nutrition) as non-milk extrinsic sugars (NMES). NMES include all added sugars, honey, syrups and sugars extrinsic to the cellular structure of whole fruit and vegetables. NMES therefore include sugars naturally present in fresh fruit juices and fruit concentrates. However, SACN has now replaced NMES with the term ‘free sugars’ [2]. This term is used by other authorities including the WHO and defined by the WHO as sugars (mono and disaccharides) added to foods and beverages by the manufacturer, cook or consumer and sugars naturally present in honey, syrups, fruit juices and fruit juice concentrates [3]. The difference between NMES and the WHO definitions is that the WHO definition of free sugars excludes fruit sugars in stewed fruit, dried and fruit canned in water, but not in sugar syrup. The term ‘added sugars’, sometimes found in consumer advice material, includes those added to food and drinks during processing, including natural sugars derived from milk and fruit, manufacture or preparation, but excludes sugars naturally present within milk and whole fruits as consumed. A more comprehensive definition of added sugars is given by the European Food Safety Agency. For the sake of consistency, the WHO definition of free sugars has been adopted for this publication (Fig. 3.1). The WHO recommends that the free sugar contribution to an individual’s total energy intake should be no more than 10% and suggests a further reduction to below 5% [3] to protect oral health throughout the life course. In the UK the Scientific Advisory Committee on Nutrition (SACN) recommends that the population average intake of free sugars should not exceed 5% of total dietary energy, as more fully explained below [2]. This recommendation is consistent with the WHO recommendation for individuals as if all individuals within a population consumed less than 10%, the average is likely to be around 5%. In its systematic review of the evidence, SACN found that: • High levels of sugar consumption are associated with a greater risk of tooth decay. • The higher the proportion of sugars in the diet, the greater the risk of high energy intake.

3.2 Sugars in Food and Drinks

31

Free Sugars WHO definition – WHO 2015 3

Free sugars include:

All sugars added to foods by the manufacturer, cook or consumer

Plus the sugars that are naturally present in honey, syrups, fruit juices and fruit juice concentrates.

Free sugars do not include:

The sugars naturally present in whole fruit and vegetables (intrinsic sugars)

Stewed fruits, dried fruit and fruit canned in water, but not canned in sugar syrup

Sugars naturally present in milk (lactose and galactose).

Fig. 3.1  The WHO free sugars definition and interpretation

• Drinking high-sugar beverages results in weight gain and increases in BMI in teenagers and children. • Consuming too many high-sugar beverages increases the risk of developing type 2 diabetes. In light of these findings, SACN recommends that: • Free sugars should account for no more than 5% daily dietary energy intake, from 2 years upwards. • The term free sugars is adopted, replacing the terms non-milk extrinsic sugars (NMES) and added sugars. Free sugars are those added to food and drinks or those naturally present in honey, syrups and unsweetened fruit juices and fruit juice concentrates but exclude lactose naturally present within milk and milk products, whole fruit, vegetables and grains. • The consumption of sugar-sweetened beverages (e.g. fizzy drinks, soft drinks and squash) should be minimised by both children and adults.

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The reason that free sugars are implicated is that they can rapidly enter the plaque bacteria and be converted to acid and are often frequently consumed. Sugars naturally present in whole fruit and vegetables – and eaten as such as part of a normal healthy diet – are not considered to be cariogenic. Sugars in milk while extrinsic are not linked to caries risk when naturally present in milk, although it has been suggested that leaving an infant with a bottle of milk formula or cow’s milk for long periods may pose a risk, especially when the child is asleep. If a child is left with a bottle or comforter (soother), it should only contain water. Systematic reviews show breastfeeding up to 12  months is associated with reduced caries risk, and it also helps in the development of the teeth and prevents malocclusion [4]. However some studies suggest that breastfeeding beyond 2 years may carry a risk of increased caries, especially if a pattern of frequent breastfeeding on demand becomes established. See Chap. 9 for more information about breastfeeding. Most adults and children in the UK consume too much free sugars. The UK National Diet and Nutrition Survey found that the most common free sugars in the UK diet are: • • • • • •

Sugar, preserves and confectionery (up to 27% of daily intake). Non-alcoholic drinks (25%) Biscuits, buns and cakes (20%) Alcoholic drinks (11%) Dairy products (6%) Savoury food (5%)

Breakfast cereal consumption, especially by children, is a cause of concern and not just the sugar-coated varieties since some plain breakfast cereals contain more than 20% sugars. As the frequency and amount of free sugar consumption are related, a reduction in either or preferably both can make a major contribution to the improvement of both general and oral health, as well as helping to maintain a healthy diet. For most people reducing the frequency of consumption is a good way to help them achieve a reduction in the amount consumed. However, the first line of advice should always be to lower the amount of free sugars consumed. Adults and children should be encouraged to drink water and low-fat milk rather than soft drinks to help reduce free sugar intakes. Fruit and vegetables are an essential part of a healthy diet; however all fruit juices (including smoothies) have a high concentration of free sugars. While one 150 mL portion of juice (a small cup) is permitted within the fruit and vegetables recommended by the ‘5-a-day’ programme, sponsored by Public Health England, from a health perspective, higher consumption could increase the risk of dental caries and other diet-related conditions such as type 2 diabetes. Fresh fruit juices may only constitute one of the five daily portions, limited to 150  mL, and this point should be stressed when giving dietary advice. Lactose, the sugar present in milk, is often added during manufacture to foods or drinks and as such is a free sugar. When naturally present within milk, it appears to be virtually non-cariogenic, hence the distinction.

3.2 Sugars in Food and Drinks

33

The common free sugars are sucrose (refined from beet and cane), glucose, maltose (extracted from many foods) and fructose (extracted from fruit). Fruit juices and honey contain a mixture of fructose, glucose and sucrose. These sugars are also free sugars when naturally present in natural unsweetened fruit juice, honey and syrups and when used as an additive to foods and drinks. High-fructose corn syrups and fruit juice concentrates are also used as commercial food and drink sweeteners, as is lactose. Significant amounts of glucose are now made industrially from starch. While sucrose is highly cariogenic, animal studies have shown that both glucose and fructose will readily produce caries and combinations of these sugars appear to be as cariogenic as sucrose alone. Furthermore, there does not appear to be a safe level for sugar concentration in food and drinks, as this is linked in a complex manner with physical consistency. Indeed, in solution, sucrose concentrations below the taste threshold can generate acid in plaque (Tables 3.1 and 3.2). Dietary starch, which is a polysaccharide (a simple or branching chain of glucose units), varies considerably in form as a result of heat processing. They are partially converted to alpha-limit dextrins, maltose and glucose in the mouth by enzymes in saliva, and these sugars are then available for metabolising into acids by plaque bacteria. However, starch-rich staple foods, eaten raw or cooked such as bread, potatoes and rice, are an important part of a healthy balanced diet, and the rate of conversion to glucose is slow. Consequently dietary starch by itself is very much less important than dietary free sugars as a cause of dental caries. Raw starch, such as found in fruits and vegetables, is virtually non-cariogenic. Research conducted in the UK during World War II showed that while starch consumption increased and sugar consumption decreased, caries prevalence decreased despite the increase in starch consumption. Recent research has shown that when starch is cooked at very high temperatures, such as for the production of some snack foods including biscuits and cakes, the conversion to glucose in the mouth can occur more rapidly [5]. From a theoretical aspect, sugar-free chewing gum may have a positive benefit for dental health by increasing salivary flow during chewing, which helps to neutralise plaque acid activity. The majority of clinical studies have found a positive benefit. Table 3.1  Cariogenic sugars Sugars and other compounds added to food and drinks during processing, manufacture or before consumption as sweeteners and that have the potential to cause dental caries Glucosea Maltose Maltodextrins Hydrolysed Sucrosea starch Fructosea Invert sugar Oligofructose Glucose syrup Corn syrup a Non-cariogenic when contained in the whole fresh fruits, vegetables and grains Table 3.2  Products of mixed sugars Products that are essentially a mixture of sugars Brown sugar (mainly sucrose) Treacle Maple syrup Honey

Golden syrup

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3.3

3  Diet and Oral Health

Xylitol and Other Non-cariogenic Sweeteners

There is evidence from laboratory and clinical studies that xylitol, a sugar alcohol, used as a bulk, but not a low-calorie sweetener, is non-cariogenic and may also suppress the growth of some acidogenic bacteria in the plaque biofilm. The use of xylitol in chewing gum has been the subject of a number of extensive clinical trials, the majority of which have shown a significant caries-inhibiting effect; however the evidence is not conclusive [6]. Another sugar alcohol, erythritol, appears to have similar properties and is also used in the food industry. If consumed in excess, bulk sweeteners such as sorbitol can have a laxative effect. While overt diarrhoea is a rare side-effect, children are at greater risk. There is a general requirement in many countries for these sweeteners to carry the labelling that excessive consumption may produce laxative effects. Furthermore they are caloric sweeteners and may contribute to energy intake and the risk of obesity and related morbidity and are unlikely to reduce a sweet taste preference. Combinations of sugars and intense noncaloric sweeteners such as saccharin are used in some products; however, the latter will not have a protective role, and such products must be classified as cariogenic. Concentrated soft drinks, which are the main source of artificial sweeteners in the diet of young children, should be diluted with extra water for these young consumers to avoid excessive intake and are not recommended for children under the age of 3 years. It is advised that ideally drinks containing artificial sweeteners such as aspartame or saccharin should not be given to young children. If they are given, they should be diluted with at least ten parts of water to one part concentrate. Even if well diluted, such drinks are acidic and have the potential to cause erosion (see Chap. 6) (Tables 3.3 and 3.4). It must be remembered that manufacturing problems related to sugar substitution are not just limited to sweetness, cost and safety. Sugars give bulk to many foods and influence properties such as viscosity, texture and shelf life. It is worth noting that there is no evidence that substituting low-calorie sweeteners for sugars weans people off a sweet taste preference. Table 3.3  Non-cariogenic caloric sweeteners Bulk sweeteners mainly used to add sweetness, calories and bulk to confectionery products Maltitol syrup Isomalt Lactitol Maltitol Mannitol Sorbitol Xylitol

Table 3.4  Intense noncaloric sweeteners Intense noncaloric sweeteners added in small amounts often to soft drinks Acesulfame K Cyclamate Saccharin Sucralose Neohesperidin DC Aspartame Stevia Thaumatin

3.4 The Pattern of Free Sugar Intake

3.4

35

The Pattern of Free Sugar Intake

After consuming free sugars, acid is rapidly generated in the dental plaque, and, within 1–2 min, plaque pH has fallen to levels that favour enamel demineralisation. The return to neutrality takes between 20 min and 2 h, depending on such factors as salivary flow rate and buffering capacity as well as plaque thickness and composition. Maximum acid production is achieved by modest concentrations of free sugars, beyond which increased concentrations do not give a greater fall in pH. However, frequent intakes of free sugars will not allow time for the pH to recover and will prolong the period of plaque acidity. This pattern may allow demineralisation to exceed remineralisation resulting in a progressive loss of minerals from enamel as illustrated in Fig. 2.4. While these are theoretical considerations arising from laboratory studies, the amount of free sugars consumed has been shown to be independently related to caries experience, and as frequency and amount are related, advice must be to reduce both. The frequency and time of consumption of sugar-sweetened foods and drinks are thought to be factors in determining caries levels, although strong evidence is lacking. Sugars consumed with main meals may be of less significance because they are cleared from the mouth by other foods together with the high salivary flow rate generated by eating, although again strong evidence is lacking. Other foods taken as part of the meal, such as cheese, may help stimulate salivary flow and raise the calcium level in plaque so that remineralisation is promoted. However, sugar-sweetened items consumed between meals appear to have a much more detrimental effect. The WHO has recommended that ‘free sugar’ intake by individuals should contribute no more than a maximum of 10% of total energy intake and preferable 5% [3]. While this advice provides a pragmatic guide for individuals, there is no completely safe frequency of consumption because of factors such as variations in the nature and composition of saliva, the pattern and time of consumption of the sugars and the nature of the sugar item. The WHO has suggested a further reduction of free sugar intake to less than 5% total energy intake as a threshold to protect general and oral health [3]. Some research has suggested that bedtime might be the worst time to consume a sugar-sweetened drink or snack due to the low salivary flow rate during sleep and that toothbrushing is unlikely to remove all traces of any sugary snack taken before bed. However a systematic review suggests that the evidence is consistent but of low quality [7]. However, one of the benefits of low salivary flow at night time does mean that when the teeth are brushed with a fluoridated toothpaste, the fluoride will remain in the mouth for a prolonged time and will not be cleared so quickly by the saliva. Sugars in medicines can also cause decay. Many paediatric medicines, including those sold without prescription, have sugar-free alternatives. Clinicians should prescribe sugar-free medicines and parents/carers should request them. Pharmacists should be well informed about the harmful effects of sugar in medicines and should stock and recommend sugar-free alternatives to the most

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3  Diet and Oral Health

commonly used prescription and general sale medicines, which should be the cheapest and easiest to dispense. Policies should be in place in all countries so that the training and regulation of pharmacists and all healthcare professionals support the use of sugar-free medicines, especially for children. All dental health professionals should have the skills and confidence to provide their patients with healthier eating advice, including how to limit free sugar intake, and they should receive adequate education in diet and nutrition. All patients or their parents or carers should receive dietary advice to reduce free sugars within the context of a healthy diet for the prevention of all non-communicable diseases. Dietary advice should focus on reducing the amount of free sugars consumed; encourage the consumption of fresh fruits and vegetables, nuts, seeds and wholegrain starch-rich foods; and discourage the consumption of all drinks containing free sugars [8]. The WHO recommends that intake of free sugars should provide ≤10% of energy intake and suggests further reductions to

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