Information is only as good as its source: reliable evidence-based research
Evidence-based dentistry is not simply the clinical application of new knowledge. Delivery of quality dental services relies upon an appropriate synthesis of the clinician’s experience and judgment, complemented by contemporary evidence-based scientific information, taken together with individual patient circumstances. In fact, patients are increasingly knowledgeable and often present to the dental office with apparent evidence in hand.
The American Dental Association defines evidence-based dentistry as “an approach to oral health care that requires the judicious integration of systematic assessments of clinically relevant scientific evidence, relating to the patient’s oral and medical condition and history, with the dentist’s clinical expertise and the patient’s treatment needs and preferences.”
As the busy practitioner seeks to implement such an approach to practise, it is important to remember that the reliability of information is only as good as its source. A readily available, convenient source of information is the dental literature.
Dentists are exposed to a voluminous amount of scientific and technical material, whether in print publications or various electronic formats. Clinical decision-making requires an ability to evaluate the validity of the information presented and to assess its applicability to every day practice.
The experimental study, as opposed to the observational study, represents the highest level of clinical study design. In the hierarchy of evidence, the randomized controlled trial (RCT) is the best example of an experimental study. In these studies, the effect(s) of an intervention or therapy is evaluated in a treatment group compared to a control group.
Even when presented with a strong study design such as the RCT, it is important to appraise these studies based on a number of criteria related to methodology and conclusions. Consideration must be given to such variables as an adequate size of a representative population, whether the patients and researchers were blinded to the treatment, appropriate followup, researcher bias and/or whether the outcome was statistically significant or clinically relevant.
In addition, publication in a peer-reviewed journal is preferred. It may not be reasonably possible or ethical, however, to subject participants to certain conditions as required in an RCT, so an observational study is frequently an acceptable substitute. In these types of study, an outcome can be evaluated in a group of people, but there is little control of variables that may affect the results.
The meta-analysis and systematic review of RCTs represent the highest standard of evidence. A systematic review is a rigorous process of literature review that is developed to interpret the available evidence in order to answer a specific question. These are essentially a review of completed studies and may include several study designs other than the RCT depending on their content and applicability. Abbreviated forms of systematic reviews, including critical summaries and treatment recommendations, are available for the busy clinician. Meta-analysis is a statistical technique able to summarize and add precision to the results of several studies.
Although the search for evidence and development of critical appraisal skills are important, this does not mean that high-level, unequivocal evidence is always freely available or accessible. For example, The Cochrane Database of Systematic Reviews requires institutional access to a full text format. As The British Dental Journal recently remarked, “unfortunately, the evidence base to support the effectiveness of many of the commonly performed treatments in dentistry is limited both in quantity and quality.”
That said, there are many helpful resources available which focus on evidence-based information. The College provides a link to several websites where such information is accessible.
The Centre for Evidence Based Dentistry in the UK
The Centre for Evidence Based Dentistry is the editorial base for the Evidence Based Dentistry Journal (which is an official publication of the British Dental Association). This journal selects original and review articles which are summarized in abstracts and includes expert commentary.
This website also presents evidence from the Cochrane reviews and offers links to the British Dental Journal.Evidentista
The Evidentista site includes a database of clinical questions and answers covering a variety of dental topics. It also includes critical summaries from the Evidence Based Dentistry Journal as well as evidence from the Cochrane Library and NICE (National Institute for Health and Clinical Excellence in the UK).
American Dental Association Center for Evidence-Based Dentistry
The ADA center website provides a database of systematic reviews and includes appraisal of the evidence through critical summaries. Clinical recommendations, guidelines and links to other resources are also offered.
Canadian Dental Association’s Oasis project (OnlineAdvice and Searchable Information System)
The Oasis project consists of three complementary components and provides access to peer-reviewed clinical information. JCDA Oasis offers both clinical resources as well as an interactive platform which encourages interdisciplinary communication between colleagues. Evidence-based care is the focus of many continuing education courses, websites and dental literature. An ongoing awareness and review of the evidence will help support clinical decisions and facilitate the provision of quality care to our patients.