You broke a tooth or have a deep cavity. Your dentist tells you that this is a big problem for your tooth. The dentist offers you two treatment plans. One involves root canal treatment, a post, and a crown. The other plan involves replacing this tooth with a dental implant supported crown. How does your dentist know which treatment is the best? Your dentist may ask you to decide which treatment is the best for you. How are you supposed to know which is best. Frankly, how does your dentist know?
There are many ways that your dentist might decide on a treatment recommendation. Let’s consider the treatment for your broken tooth. Your dentist may have the opinion that root canal treatment and a crown will last longer than a crown on a dental implant. It is important to know why the dentist believes that is so. Perhaps your dentist is older with the experience of providing root canal treatment and crowns to several teeth and replacing several teeth with implant supported crowns. According to this dentist’s memory, teeth that were repaired with root canal treatment and crowns were more successful than dental implant supported crowns. That is his opinion based on his experience and his memory. This is called expert opinion.
This dentist may pass his expert opinion on to friends, acquaintances, and students. The problem with expert opinion is that it may be colored by biases. Some dentists may be biased in favor of new techniques. Some may only remember the times their treatments were successful. It may be that all of the patients whose treatment failed went to another dentist for a replacement. Researchers generally do not trust expert opinion.
Historical studies provide better evidence than expert opinion. Researchers look at the records of treatment that was already completed and try to understand which treatment was successful for the most patients.
Even better evidence results from randomized controlled trials. In these experiments,researchers randomly assign patients to have different treatments. The researchers and the patients should not know which treatment the patient will receive. Then, the researchers follow the patients and note their success over time. It is less likely that doctors will sway the results to one treatment or the other if they have less control over the choice of the treatment.
It is likely that different researchers who study the same treatments will have different results. Researchers are able to combine the results of several studies or experiments together into a systematic review. Systematic reviews are complex and lengthy papers that provide more reliable results than single historical studies or randomized controlled trials. Although systematic reviews provide excellent evidence on which to base a decision, they are hard to understand.
Critical summaries are short reports on systematic reviews. Dentists, other health care providers, and savvy lay people can read a critical summary and understand the results of the systematic review and why it is important.
All of the preceding reports, papers, and studies may assist you and your dentist in your decision. However, this is all a form of technical writing that includes scientific language and statistics that are difficult for most non-scientists to understand. Authors of plain language summaries use simple English to explain the results of a critical summary or a systematic review. This kind of report may be the most useful for dental and medical patients.
The American Dental Association’s Center for Evidence Based Dentistry maintains a very organized library of systematic reviews, critical summaries and plain language summaries on the web site http://ebd.ada.org. To use the site, click on “Systematic Reviews”. Look through the subject headings for the one that seems to apply to your treatment. Then click on the review that interests you. Some systematic reviews have accompanying critical summaries and plain language summaries. If you do not fully understand what you read, bring or email a copy to your dentist.
Here is a systematic review that asks if children who live with smokers are more likely to get cavities than children who are not exposed to secondhand smoke: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3108123/
Here is a critical summary of that systematic review: http://jada.ada.org/content/145/2/179.full
Here is a plain language summary of that systematic review: http://ebd.ada.org/PLS/PlainLanguageSummaryDetail.aspx?plsId=3a14264e-0aa2-49a5-81c2-a6ea3890662f