In the past two entries, we have reviewed EBD and defined it. Today, I would like to review evidence. We all had a course in dental school regarding dental evidence. If your course was anything like mine, it was Spring semester of Freshman year buried deep in big time courses like microbiology, pharmacology, and physiology. It's not difficult to see why I don't remember more from the class. As practicing dentists, it's time to review this information because it is a very useful tool for our practice.
A hierarchy of evidence exists to guide clinical decision making so that the highest level of evidence is considered for a given question.
At the bottom of the evidence rankings, we have animal research and in-vitro research. These studies do not have human involvement therefore must be closely analyzed to determine their relevance.
Just in front of these are case reports, editorials, and opinions. While valuable, these really have no variable and control type approach or sample sizes greater than one. These can give great information, but again, they must be closely analyzed. Gordon Christensen has made a career on these. As I said, these can hold very good information, however to claim a case report as strong evidence would be an overstep.
Over the next few days, I will review the following levels of evidence. Stay tuned!