Allan Hackshaw established and led the course on evidence-based dentistry at Barts & the London School of Dentistry and is now deputy-director of the cancer trials centre at University College London. Elizabeth Paul is a Lecturer at the UCL cancer trials centre. Elizabeth Davenport is Professor of Dental Education, Barts & the London School of Dentistry.

• Foreword viiiPreface ixAcknowledgements xii1 Evidence-based dentistry: what it is and how to practice it 1What is evidence-based dentistry? 1Why do we need evidence-based dentistry? 2How to practice evidence-based dentistry 32 Counting people: understanding percentages and proportions 10What is the aim of the study? 10How was the study conducted? 11What are the main results? 12The implications of conducting a study based on a sample of people 15How good is the evidence? 19What does the study contribute to dental practice? 233 Taking measurements on people 31What is the aim of the study? 31How was the study conducted? 32What are the main results? 35Normal distribution 35Interpreting the results from non-symmetric data 404 Comparing groups of people and examining associations 44Comparing two percentages (or proportions) 44Comparing two means 51Examining associations 555 Assessing the effectiveness of treatments 68Main design elements of randomised clinical trials 69A clinical trial based on counting people 71A clinical trial based on taking measurements on people 89Appendix I. Guidelines for the appraisal of a clinical trial 996 Determining risk factors for and causes of disease 115Association, causality and confounding 116Cohort studies 119An example of a cohort study 121Case–control studies 131An example of a case–control study 132Appendix I. Guidelines for the appraisal of an observational study 141Appendix II. Calculation of odds, risk, odds ratio and relative risk 1437 Detecting disease 154Conditions for a worthwhile screening programme 1568 Study design issues 172Types of study 172Selecting the sample 172Sample size 173More observational studies 177Bias 178Confounding 180More on clinical trials 182What is the strength of evidence for causality from different study types? 1839 Reviewing all the evidence 186Searching for information 186Conflicts of interests in published research 188Systematic reviews 18910 Summary of statistical concepts 205Suggested answers 209Further reading 219Index 222

"Suitable for both undergraduates and professional dentists with years of practice under their belts alike, this 200-page paperback aims to provide a basic understanding of research in dentistry and how it is conducted and reportedThis book provides an invaluable insight into how scientific findings in dentistry are researched and reported."bdanews, December 2006