Evidence Based Dentistry
Table of Contents
Latest update December 2012
by Mick Draper
Part 1 of a 4 part course on Evidence Based Dentistry
This course presents a brief overview of evidence based
health care with some dental examples. The emphasis will be on how to search
for articles using electronic databases PubMed, Embase, Dentistry and Oral Sciences Source and Cochrane Library.
Part 1 introduces the principles of evidence based practice
Health Care is (perhaps) a new paradigm in providing
objective health care.
Free access to databases such as PubMed, plus cheap computers
have made it possible for practitioners to search for outcomes based, objective research, and apply the results to their patient populations.
It's also possible for patients to find a lot of information on many medical conditions. Patients may find information online and ask practitioners for their opinions.
Show me the evidence
Uni of Adelaide community can click here to read
Rachel C Vreeman, & Aaron E Carroll 2007. Medical myths BMJ 335:1288-1289 (22 December)
The authors examine the evidence for 7 commonly quoted medical myths, but read the responses as well because maybe those examining the "myths" don't know everything.
Evidence based practice comes from three approaches to medical practice that were used in the late 18th and early 19th centuries.
The Clinical Methods approach was to use received wisdom, experience, anecdote, and observation to decide how to proceed in each case.
The Pathophysiology approach was based on laboratory investigation and theoretical extension to practice. This was developed by Claude Bernard who thought that a scientific approach was the way forward. He thought that understanding the science of pathology would provide cures or prevention methods for many diseases. This is the method taught by med schools during most of the second half of the 20th century and was the received wisdom of that era.
Claude Bernard Wikipedia siteThe Epidemiological or Numerical approach was championed by Pierre Louis. He felt that received wisdom wasn't working for treatment of infectious diseases. He stated that ‘a therapeutic agent cannot be employed with any discrimination or probability of success in a given case, unless its general efficacy in analogous cases, has been previously ascertained’.
Pierre Louis is famous for challenging bleeding as a treatment for fevers. Pathophysiologists noted that inflammation was associated with increased blood flow, and concluded that bleeding would be therapeutic! Louis’ numbers showed that bleeding didn't work. This also produced hostility as practitioners didn't want to treat their patients based on 'somebody else's numbers'.
Louis was only partially successful, but developments in the late 20th century in Britain and Canada increased the profile of clinical epidemiology.
Below is the link to an article on the history of evidence based practice. It describes the history of the three approaches to medicine in Europe in the 19th century and developments in the 20th century.
Swales, J. 2000. The troublesome search for evidence: three cultures in need of integration. Journal of the Royal Society of Medicine 93 402-407.
Recent History of Evidence Based Practice
In Britain, Archie Cochrane worked on the health services provided to Welsh miners. He felt that the health care was inadequate and inconsistent. He looked for a method of evaluating health care and decided that randomised controlled trials were most useful because they reduced the bias that hindered other methods. Cochrane's ideal was for each specialty to produce a series of meta-analyses of all the trials in the discipline, and to regularly update these meta-analyses.
Definition of Meta-analysis
A statistical method of combining the results of a number of different studies in order to provide a larger sample size for evaluation and to produce a stronger conclusion than can be provided by any single study. From GreenFacts.org
At McMaster University David Sackett founded the world's first department of clinical epidemiology. He and his colleagues compiled the evidence from trials as an aid to practitioners and policy makers. This led to examination of the costs involved in the treatments for various conditions, providing evidence for governments to decide how best to spend taxes in health care.
In 1991 the ACP journal club was launched by the American College of Physicians to provide practitioners with new evidence and its evaluation.
In 1995 the journal Evidence based medicine for primary care and internal medicine was launched on cd-rom and from 2000 was available online.
In 1988 the Oxford Database of Perinatal Trials was launched. This database collected evidence from many trials and synthesized the results in a single database. This developed into the Cochrane Collaboration and its Cochrane Library, a dynamic form of publication where authors publish systematic reviews on interventions and are required to keep the reviews updated as new evidence becomes available.
Chronology of The Cochrane Collaboration
The Value of Randomised Controlled Trials
RCT's reduce the bias in testing treatments in clinical research. With neither practitioners nor patients knowing who is receiving treatment and who is part of the control group, much of the bias in testing interventions can be removed.
The value of randomised controlled trials was dramatically shown in testing of anti-arrhythmia drugs. Anti-arrhythmia drugs were used well into the 20th cent to treat ventricular extrasystole following myocardial infarction. A trial of these drugs was stopped when the test group showed higher mortality than the controls.
There is still a gap between clinicians who are taught medical science and the need for being aware of individual biology, and those who use the tools of epidemiology such as the randomised controlled trial, and meta-analysis. In the 1960's Alvan Feinstein was concerned about the number of articles presented to conferences of clinical bodies in the USA that were on nonhuman, nondisease clinical research. He accused medical science institutions of being preoccupied with rat turd grinding in the lab. Feinstein applied mathematical techniques to clinical medicine. His many works focused on the goals and the methods required for effective clinical medicine that went beyond received wisdom from laboratory studies.
Evidence based practice should incorporate
having the best available evidence,
using clinical judgment based on the experience of the practitioner,
being patient centred and
continuing the evaluation and improvement of the processes of clinical practice
Evidence based practice is ... The conscientious, explicit, and judicious use of current best evidence in decision making. It customizes worker experience with the various forms of evidence to the specific problem/situation under investigation. (Sackett, et al, 1997).
Article by David Sackett on expert opinion in medicine
The sins of expertness and a proposal for redemption (news article)
BMJ;320:1283 ( 6 May 2000 )
Evidence-based practice is "a total process beginning with knowing what clinical questions to ask, how to find the best practice, and how to critically appraise the evidence for validity and applicability to the particular care situation. The best evidence then must be applied by a clinician with expertise in considering the patient's unique values and needs. The final aspect of the process is evaluation of the effectiveness of care and the continual improvement of the process" (DePalma, JA 2000 Evidence-based clinical practice guidelines. Seminars in perioperative nursing 9(3) 115-120.)
"Evidence based clinical practice is an approach to decision making in which the clinician uses the best evidence available, in consultation with the patient, to decide upon the option which suits that patient best".
Source: Muir Gray JA. (2001) Evidence-based healthcare. 2nd edition page 17. Edinburgh ; Sydney : Churchill Livingstone
BSL Call number 362.1068 G779e.2
While these definitions are directed at the practitioner-patient relationship, policy makers are interested in EBP if it can reduce expenditure and stop useless or harmful treatment.
|% of GDP||Total Expenditure per Person
AIHW Expenditure From Australian Institute of Health and Welfare
Need for objectivity and evidence of effectiveness in
Geographical variation in interventions
Need to cease ineffective treatments to contain costs to national health systems and patients
Need to move from practitioner oriented outcomes to patient oriented outcomes
1 Acknowledge information gaps
2 Formulate answerable questions to fill gaps
3 Know the sources of evidence
4 Know how to search sources
5 Quickly assess the usefulness of information
6 Critically read the literature/Evaluate clinical guidelines
7 Integrate best evidence, and clinical judgment for the benefit of
8 Without bias, present intervention options to patients
9 Evaluate and record the effectiveness of the whole process
Know the limitations of evidence based health care
There may not be any information on a topic, or the evidence may only be at case level The populations tested may not share the same characteristics as your patients. The patients in the trials may not have been compliant. The methods used might not always be appropriate The conclusions of the authors might not always match their results. The time required to become efficient at evidence based practice might be daunting.
Time and Skill Constraints
Practitioners have only a few minutes each day for reading
PubMed has 22 million+ refs to search
Unpracticed users of Medline/PubMed can take more than 30 minutes to find article citations
The relevance of many of the references can be low
Most practitioners are willing to learn the skills required to perform quick effective searches, but often don't have time to use the skills. Many busy practitioners prefer to use a product that regularly updates the best practice for particular conditions.
There are subscription services that provide up to date best practice information. The University of Adelaide Library has access to
- BestPractice This is a point of care information source from the BMJ Group combining research evidence, guidelines, and expert opinion. There isn't a lot on dentistry in this database yet.
- MD Consult This database includes searchable clinical ebooks, ejournals, review journals, a drugs database, news, practice guidelines, patient handouts, and cases on a wide area of clinic medicine.
- UpToDate Covers diagnosis, treatment and evidence for many medical disorders. Students have remote access, for staff this resource is available only on campus at Uni of Adelaide.
The ability to acknowledge a gap in your knowledge
is a clinical skill.
Do you know enough about diagnosis, & intervention for a condition, as presented, to manage the patient to the best outcome? Do you know what you don't know?
If you ask the wrong questions you may be flooded with information, or find nothing relevant to your patients.
Do you need to get evidence that relates exactly to your patient or group of patients, or all the evidence that relates to all patient groups? (age, sex, ethnicity, medically compromised, outcome desired by patient)
What sorts of intervention can you provide, what sorts of interventions will need referral?
Do you need to compare different interventions?
To help formulate questions and begin to produce a search strategy it can be useful to use the PICO method. This focuses your thoughts on the concepts that you need to include in your searches. Most evidence based practice questions can be formulated in 4 parts.
Population(s), patient(s), participants, or problem(s)
Who are the patients? What is the clinical problem or concern with these patients?
Consider the conditions they suffer, their age, ethnicity, gender, geographical location etc.
Are you interested in therapy, diagnosis, aetiology, prognosis, prevention, or education
Are there co existing problems? Have the patients been exposed to a harmful agent? (drugs, pollutants, poisons)
Interventions or indicators
What is the intervention, diagnostic test, exposure, prognostic factor?
What do you want to do for the patient? Prescribe a drug, run a diagnostic test, or use surgery?
Comparator(s) or control(s)
Do you want to compare two interventions, a drug and placebo, intervention and no treatment, two or more diagnostic tests? You might not always need to include comparison in your search.
What outcome are you trying to achieve, measure, prevent or avoid? (relieve symptoms, restore or improve function, prevent or reduce the number of events) You don't need to include a particular outcome if you are looking for all outcomes of a particular set of interventions.
|Population||Intervention 1||Comparator, Intervention 2||Outcome|
|halitosis||chlorhexidine + Zn||Listerine||(levels of) volatile sulphur compounds|
|bad breath||essential oil mouth wash||volatile sulfur compounds|
|oral malodour||oral flora|
|oral malodor||patient satisfaction|
Here are 3 web sites that might help with using PICO.
What is the PICO Model Includes links to work sheets. From The Library of the University of Illinois at Chicago
The Well Built Clinical Question from Duke University Medical Center Library and Health Sciences Library, UNC-Chapel Hill
Asking Focused Questions from Centre for Evidence Based Medicine
Textbooks can be out of date when published.
Textbooks often include 'established knowledge' that doesn't change (much) such as anatomy, physical properties of dental materials, drug adverse effects.
Texts can sometimes provide useful summaries.
These provide information on professional news, government policy, research and practice trends.
Angle Orthodontist; Community Dentistry and Oral Epidemiology; Journal of Periodontology; Journal of Prosthetic Dentistry; Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontology
There are more full text dentistry ejournals here for The University of Adelaide community.
There are now more journals that are specifically aimed at evidence based practice.
Bandolier including Bandolier Learning Zone with info on how to understand clinical trials, statistics, clinical guidelines, and articles (including Bisphosphonates and jaw osteonecrosis)
Most practitioners will keep an electronic and/or paper collection of books, reprints, and other material used in everyday practice. The University of Adelaide community has access to a site licence for the bibliographic database management system called EndNote.
Embase a commercial health sciences database similar to PubMed.
Dentistry and Oral Sciences Source (DOSS) a database with links to a significant amount of full text
Article types and their usefulness for evidence based health care
While test tube experiments are essential in all areas of medicine including dentistry, clinicians can't base treatment on the results.
Some useful results have come from animal experiments, and while these may indicate the usefulness of human trials, clinicians can't use these articles.
These are often memorable and can serve as a reminder for diagnosis and treatment, but you can't base a practice on small populations (1 patient) where bias may be present.
Phase I trials
Usually conducted on small numbers of healthy volunteers to look for adverse effects. These results aren't appropriate for clinicians working with patients.
Phase II trials (Case Series)
Mostly these use small numbers of selected patients, or a series of patients often without a control group to test the outcome of an intervention. Results of Phase II Trials are not usually considered sufficiently objective and rigorous enough to use in clinical decisions.
Phase III trials
Large long term trials on patients, usually with randomized control, double or single blinding, control groups, placebos etc. These trials can be used to make clinical decisions.
Phase IV trials
These are usually post marketing trials on very large numbers of patients to gauge the long term safety and find rare adverse effects of interventions. Useful for clinical decision making.
These are peer reviewed articles that bring together all the objective studies on interventions for particular conditions. Sometimes authors do this to compare interventions, and sometimes to join study results to increase the size of the population tested. If the original articles are not randomized controlled trials, then the authors should explain why they are used in the analysis and what adjustments were made in the statistical analysis to include them. These are useful for clinical decisions, often called the gold standard.
Centre for Evidence Based Dentistry Systematic Reviews Information sources on systematic reviews.
Patients with a particular condition are followed over time and compared with a control group. Cohort studies aren't as reliable as controlled trials but are useful in situations where it wouldn't be ethical to run a randomised trial. Types of cohort studies include
Cohort studies can be used for making clinical decisions.
Longitudinal Studies where particular groups or individuals within a cohort are studied. Follow-up Studies study the effect of exposures, procedures, or characteristics such as a disease. Prospective Studies study the incidence or mortality in subgroups after their selection.
Clinical Practice Guidelines
Should be evidence based serial statements to assist in diagnosis and treatment of particular conditions. Care should be taken to ensure that these are NOT based only on expert opinion. Look carefully at the evidence summary to ensure that the evidence is both comprehensive and up to date. You'll also need to see if it's possible to follow through with the guideline in your situation.
Guidelines for the removal of wisdom teeth From NICE (National Institute for Health and Clinical Excellence UK)
Dental Check-ups NICE Guideline.
HealOzone for the treatment of tooth decay NICE
You can also search the NHS Evidence database from the National Institute of Health and Clinical Excellence site.
compiled by Centre for Evidence-based Dentistry Includes the FDI World
Dental Federation Professional Resources.
MDConsult Has guidelines info including sleep apnea (sic). Uni of Adelaide community
National Guideline Clearing House From (US) Agency for Healthcare Research and Quality
Which study types are the most reliable for evidence based practice?
The Evidence Pyramid
What type of study will (best) answer your question?
Clinical examination Prospective study Diagnostic testing Prospective study Prognosis Cohort Study>Case Control >Case Series Therapy Systematic Review/Metaanalysis>RCT Aetiology or Harm Cohort Study>Case Control>Case Series Prevention Systematic Review/Metaanalysis>RCT>Cohort Study>Case Control>Case Series Cost Economic analysis
Adapted from Duke University Medical Center Library
This will be covered by other parts
of your course. You should develop the ability to quickly decide if an
article is worth reading.
Quickly find out
Does this article show a significant useful clinical effect?
If not, dismiss the article for immediate clinical purposes.
If it does, you need to ensure that the result is objective.
Is this article applicable to your patients?
Is the intervention feasible?
A free online course on Epidemiology and Biostatistics from Tufts University.
Tufts state that this course teaches the basic skills needed to critique the medical literature by providing a fundamental understanding of epidemiology and biostatistics.
Articles on appraisal
The Consort Statement A checklist and flow diagram to help improve the quality of reports of randomized controlled trials.
It's also useful for those assessing such articles. All reports of rcts should have at least the minimum set of recommendations listed in the statement
Trisha Greenhalgh's series of articles called How
to read a paper.
Barr Smith Library has the 4 editions of Greenhalg's book How to read a paper: the basics of evidence-based medicine.
The fourth edition is in the Main Collection of the Library at 616 G813h.4.
Susan E. Sutherland has written several articles on finding and assessing literature on evidence based dentistry. While some of this information is a bit dated the principles remain useful.
Sutherland, Susan E. 2001. Evidence-based Dentistry: Part I. Getting Started. Journal of the Canadian Dental Association 67:204-6.
This is a short introductory article that lists the skills needed for evidence based practice.
Sutherland, Susan E. 2001. Evidence-based Dentistry: Part II. Searching for Answers to Clinical Questions: How to Use MEDLINE. Journal of the Canadian Dental Association 67:277-80.
This article is a bit dated and quite general in covering the use of Medline (PubMed).
Sutherland, Susan E. & Stephanie Walker. 2001 Evidence-based Dentistry: Part III. Searching for Answers to Clinical Questions: Finding E-vidence on the Internet. Journal of the Canadian Dental Association 67:320-3.
Lists organizations and web sites that are more reliable than information found using search engines such as Yahoo and Google. Some of the links supplied by this article are out of date.
Sutherland, Susan E. 2001. Evidence-based Dentistry: Part IV. Research Design and Levels of Evidence. Journal of the Canadian Dental Association 67:375-8.
Sutherland, Susan E. 2001. Evidence-based Dentistry: Part V. Critical Appraisal of he Dental Literature: Papers About Therapy. Journal of the Canadian Dental Association 67:442-5.
Sutherland, Susan E. 2001. Evidence-based Dentistry: Part VI. Critical Appraisal of the Dental Literature: Papers About Diagnosis, Etiology and Prognosis. Journal of the Canadian Dental Association 67:582-5.
Critical Appraisal Tools Links to critical appraisal tools for many types of studies. From Sansom Institute for Health Research, Uni of South Australia.
An Introduction to Information Mastery This is an extensive course on how to find and appraise the literature. From Department of Family Practice, College of Human Medicine, Michigan State University.
Does learning critical appraisal
Hyde C, Julie Parkes, Jonathan Deeks, Ruairidh Milne 2000. Systematic review of effectiveness of teaching critical appraisal.
Is this a systematic review?
If not, be aware that this is a probably single study that may have design faults that can produce biased results.
If it is a systematic review, check to see that the literature surveyed is complete and up to date. Cochrane Systematic Reviews should be using only randomised controlled trial articles for the meta analysis. If results other than RCT's are used, the author(s) should tell you this and explain why other studies were included in the review.
Were patients randomly assigned to the treatment group
and was the assignment hidden from the patients and clinicians?
If not stop reading, or read this only if there are no randomised trials on the topic.
Were the prognostic indications similar for each group
(treatments and controls) at the start of the trial?
If not was there some statistical adjustment for this difference?
If not and there was no adjustment, stop reading.
Was there sufficient follow up of the patients after
Are all the patients who started the trial accounted for at the end? Anything less than 80% follow up should be considered of doubtful use. The length of follow up required will be determined by the condition(s) studied. Does the article have anything to say about compliance during the trial?
Were patients analysed in the groups to which they
were assigned? (Intention to treat)
Patients should be analysed in their original group whether they have received the assigned treatment or not, otherwise the initial randomisation is jeopardized.
Did the groups receive equal treatment apart from the
If the treating clinicians are able to determine which patients receive the intervention (e.g. surgery), then different blinded clinicians should be assessing the outcomes.
Is the best study type used for the investigation
This relates to the hierarchy of evidence. What is the best study type to use for a drug intervention? If this type of study isn't available what is the next best?
Check Centre for Evidence Based Medicine Levels of Evidence
You might need to find information on Power Analysis to determine whether the authors had a sufficiently large sample size in their study. Use any internet search engine to find sites that discuss Power Analysis.
Use Bandolier Learning Zone for some info on statistics.
Do your patients have the same condition(s) as those reported? Are they in the same age group? Are there other environmental or biological differences?
Are the patients in the study so different from your patient(s) that it would be unwise to use the study results?
Does the evidence give a clear indication of whether an intervention is likely to help? This will influence what you tell your patients. How much harm is the patient likely to suffer if there is no intervention? If there is no clear indication, objective evidence can still be presented to patients (and their families).
The judgment of whether to suggest an intervention will sometimes come down to your experience and your knowledge of the biology of the patient. Possible contraindications, and adverse effects should be presented to the patient along with any benefits of the intervention.
How to incorporate evidence in your practice
BMJ article series Getting research findings into practice
Haynes, A., & A. Donald 1998 Getting research findings into practice: Making better use of research findings. BMJ 1998; 317 : 72 (4 July )
Sheldon, T.A., G.H. Guyatt, & A. Haines 1998. Getting research findings into practice: When to act on the evidence. BMJ 1998; 317: 139-142 ( 11 July )
Glanville, J., M. Haines, & I. Auston 1998. Getting research findings into practice: Finding information on clinical effectiveness. BMJ 1998; 317: 200-203 ( 18 July )
Haynes, B. & A. Haynes 1998. Getting research findings into practice: Barriers and bridges to evidence based clinical practice. BMJ 1998; 317: 273-276 ( 25 July )
Straus, S.E. & D.L. Sackett 1998. Getting research findings into practice: Using research findings in clinical practice. BMJ 1998; 317: 339-342 ( 1 August )
Lilford, R.J., S. G. Pauker, D. A. Braunholtz, & J. Chard 1998. Getting research findings into practice: Decision analysis and the implementation of research findings. BMJ 1998; 317: 405-409 (8 August)
Bero, L.A., R. Grilli, J.M. Grimshaw, E. Harvey, A.D. Oxman, M.A. Thomson 1998. Getting research findings into practice: Closing the gap between research and practice: an overview of systematic reviews of interventions to promote the implementation of research findings. BMJ 1998; 317: 465-468 (15August)
Garner, P., R. Kale, R. Dickson,
T. Dans, & R. Salinas 1998. Getting research findings into practice:
Implementing research findings in developing countries. BMJ 1998;
531-535 (22 August)
Buchan, Heather 2004. Gaps between
best evidence and practice: causes for concern. Medical journal of Australia180
(6 Suppl): S48-S49.
How you present a range of decision options can influence what the patient decides. How you frame questions is known to be important.
Tversky, A., & D. Kahneman 1981 The framing of decisions and the psychology of choice. Science 211
Godolphin, W. 2003 The role of risk communication in shared decision making.
Clinicians should present the evidence to patients in an objective way. If the intervention has potential to harm the patient, then it is most important that the patient understands this. The patient should be encouraged to suggest acceptable outcomes.
Martina Bunge, Ingrid Mühlhauser & Anke Steckelberg 2010 What constitutes evidence-based patient information? Overview of discussed criteria Patient Education and Counseling. Volume 78, Issue 3, 316–328
Shared decision making often results in better outcomes and increased patient satisfaction.
PubMed Search designed by Mick Draper on
dentistry, attitudes to health, patient participation in decision making, and prognosis, outcome, or patient satisfaction
AND in your own search terms to make the search more specific or use the search below
PubMed search designed by Mick Draper on
Evidence based patient information
Agency for Healthcare Research and Quality Database for consumers from US Dept of Health and Human Services
MedlinePlus Patient information on more than 700 common conditions, a medical dictionary, an encyclopaedia, and drug information. From US National Library of Medicine and US National Institutes of Health
Oral Health Resources Site that includes consumer level information on Preventing cavities, gum disease, and mouth and throat cancer; benefits of water fluoridation, guides for parents on brushing children's teeth.
From (US) National Center for Chronic Disease Prevention and Health Promotion.
Record your questions, the relevant
articles you find, and whether you are modifying your treatments.
A patient centred approach assists treatment when combined with results from evidence based knowledge.
You should record your answerable questions. You should find that experience increases the number of successful searches as your questions become more relevant. You should be getting to know the appropriate MeSH and recording these. You should be quicker and better at critical appraisal. Your presentations to patients should be more objective and related to their concerns.
Go to Part 2 of Evidence Based Dentistry,Using PubMed in Evidence Based Dentistry
Go to Part 3 Evidence Based Dentistry, Embase
Go to Part 4 Evidence Based Dentistry, Dentistry and Oral Sciences Source