Current Topics in Dentistry
Author: J.W. Robbins/P. Neilson/M. Grace/M.G. Newman/R. Niederman
Evidence-based dentistry: What is it, and what does it have to do with practice?
This article was published in Quintessence International, Vol 29, No 12, (December 1998)
I. Anecdote vs Data? Case for Evidence-based Decision Making
J. W. Robbins
With regard to dentistry, these are indeed the best of times. We have available materials and techniques that visionaries could only dream of 25 years ago. We can predictably replace missing teeth with implant-supported prostheses. We can regenerate tissues lost to disease and trauma. We can provide more precise surgical and restorative therapy with the aid of improved magnification and illumination. We can restore missing tooth structure with restorations so natural in feel and appearance that they defy detection. And yet, as our profession hurdles toward the 21st century, these are also the worst of times. As a profession, we have become so enamored with our new technologies that we seem to have lost our collective common sense. Adhesive technologies have opened many doors for the restorative dentist. However, for those of us who have practiced for more than two decades, we know that many of these doors have not opened to long-term clinical success. So herein lies the problem: We have many wonderful new materials and techniques, but do we have the wisdom to use them appropriately? The Problem. In the early years of dentistry, virtually all clinical decisions were based on whim, or at best, on case reports. But as we moved into our position as a learned profession, scientific investigation began to underpin these clinical decisions. As a profession, we have taken pride in our forward-thinking approach to the provision of health care services. We were far ahead of our medical colleagues in the provision of preventive therapies. This philosophic preventive mindset, however, is based on a body of scientific knowledge that has been building for more than 40 years. Unfortunately, the scientific rigor that was essential to the development of sound preventive strategies is not as apparent in the current development of our restorative strategies.
The process has always begun with the basic scientist, through both knowledge and creativity, developing new and innovative materials. The next step has been verification of the efficacy of the new material in controlled clinical research. There are many difficulties associated with clinical research. It is very expensive and very time consuming. By the time a 3-year clinical study of a dentin bonding agent is completed, the data compiled, and results published, seldom is the tested product still available for purchase and clinical use. The new improved version of the product has taken its place, and the cycle begins again.
Due to this rapid flux of materials, the idea has insidiously crept into our thinking process that clinical research data is not necessary in our decision-making process. Since nature abhors a vacuum, the void created by this lack of relevant clinical research has been filled with anecdotal information. Hence, the genesis of our newest source of information, the nonrefereed dental journal. This new class of literature is based on the premise that the refereed literature is too slow and cumbersome. Materials are developing so quickly that there must be an information source that is current within the last 2 to 3 months.1
In a recent editorial, Miller2 aptly described this class of dental literature as an infomercial.
Typically, the article presents a case report supported by no research. It is most often written with two overriding purposes: (1) to promote a product or device and (2) to promote the career of the author. It is common to have a thinly veiled scientific article promoting a new material or device followed by a full-page advertisement for that material or device on the facing page. Since time is of the essence in this new literature format, the one step in the process that is deleted with the most expedience is the long-term clinical research!
What has happened in our profession that has allowed the anecdote to take the place of clinical data? I believe that three factors are primarily responsible for this trend. First is the lack of an evidence-based educational philosophy in dental education. Dental schools have traditionally placed a much greater emphasis on the mechanistic aspects of dentistry. An understanding and appreciation of the dental literature as a basis for clinical decision making has never been the primary educational focus in dental schools. It has been a long-standing joke around health science centers that the dental students are the only professional students on campus who cant locate the library. This lack of emphasis on evidence-based decision making has created a favorable environment for the recent explosion of the infomercial dental literature.
The second factor is the market forces that have created the dental infomercial. The vast majority of the nonrefereed literature is sponsored by dental manufacturers. It is packaged to simulate traditional refereed journals and is not presented as the commercial advertising it truly is. This blurring of the lines leads to confusion among readers. Our enthusiasm for anecdotal information is narcotic in nature. It makes us feel good when we see photographs of these beautiful, bonded restorations, even though they have had a clinical longevity of 30 minutes. We dont want to be the last in town to embrace the latest technologies, so we jump on the bandwagon. Hence, we are performing the clinical research on the new products, even though we have no means of reporting the results to our peers, especially our failures.1 It would be easier to blame the manufacturers for inundating our profession with anecdotal infomericals; but they have every right to publish this material, and it would appear that it is here to stay.
This leads to the third and certainly most important factor in our move away from the refereed literature. Many of us suffer from the late 20th-century malady of busyness. With all of the activities in our personal and professional lives, it is difficult for us to maintain our commitment to reading current literature. Since time is limited and the infomercial literature is more entertaining, we read it instead of the refereed journals. However, it is the dentist, not the manufacturer, who makes the treatment decisions. Therefore, the ultimate responsibility for making these decisions, based on the best available evidence, lies with the dentist. There are certainly several strategies available to aid the dentist in keeping abreast of the current literature. Among the most palatable of the solutions is to form a study club with colleagues of like mind. Belonging to a study club provides the members both a commitment and an economy of effort in attempting to read the literature and in making evidence-based treatment decisions.
Evidence-based decision making. When making treatment decisions, an evidence-based approach requires higher-order thinking on the part of the professional because all of the evidence is not given the same weight.3 The stronger the evidence provided in a given research report, the more weight it is given. This process requires that the decision maker first read the body of available literature on a given subject, and then have the skills to distill the results, based on the strength of each piece of data. The double-blind, placebo-controlled clinical trial is generally considered to provide the strongest evidence. The next level provides clinical data but requires a research design that precludes the use of a double-blind approach. Next are longitudinal studies, which follow group(s) of patients over time. Cross-sectional studies provide another level of data because the information is gathered at a single point in time. Finally, at the bottom of the hierarchy of strength is the case report.4 The case report is beneficial as an initial report of a technique or idea, but certainly should have virtually no weight in evidence-based decision making.
The future. There are movements within the profession that lead me to believe that there is hope. Many dental schools are moving from the force feed a baby bird approach to a problem-based learning (PBL) approach. In this PBL format, students are given hypothetical clinical scenarios that incorporate both basic and clinical science issues. The students must then use all available resources, including the library, to define the problems and develop a treatment plan. The goals of PBL education are, first, to better integrate basic and clinical sciences and, second, to develop a thinking process that will serve students for the remainder of their professional lives. To the degree that PBL education is successful in developing discriminating cognitive skills in the dental student, the impact of anecdotal information on future decision making will be diminished.
Dental schools are not alone in their recognition of the problem. Both the American Academy of Restorative Dentistry and the Academy of Operative Dentistry have formed committees to develop a framework upon which their members can make evidence-based decisons in their respective disciplines. Each year the Committee on Scientific Investigation of the American Academy of Restorative Dentistry conducts an extensive review of the body of dental literature. This review is published annually in the July issue of the Journal of Prosthetic Dentistry.5 In the most recent World Workshop in Clinical Periodontics (1996), an evidence-based decision-making approach was used to review the literature and make clinical recommendations for therapy. The reader is referred to a synopsis of the proceedings of this workshop,4 not only to read of the state of the art in periodontics, but to appreciate the elegance of the evidence-based approach in clinical decision making.
Several years ago, Simonsen6 wrote an editorial on evidence-based decision making entitled A plea for clinical trials-belief is not enough. In the editorial he quoted a short story that beautifully summarizes the problem.
One day when I was a junior student, a very important surgeon visited the school and delivered a great treatise on a large number of patients who had undergone successful operations for vascular reconstruction. At the end of the lecture, a young student at the back of the room timidly asked, Do you have any controls?
Well, the great man drew himself up to his full height, hit the desk, and said, Do you mean did I not operate on half of the patients? The hall grew very quiet then.
The voice at the back of the room hesitantly replied, Yes, thats what I had in mind. Then the visitors fist really came down as he thundered, Of course not. That would have doomed half of them to their death.
It was absolutely silent then, and one could scarcely hear the small voice ask, Which half?
Indeed, the direction of our future clinical decision-making as a profession is unclear. We can continue to make decisions based on the latest dental infomercial to cross our desks. Or we can begin to raise our hands and ask, Which half?
1. Robbins JW. According to the literature [Viewpoint, My View]. ADA News 1998;29:4