Many of us would like to believe that we practice our profession with a lot of evidence. Our belief stems from the act of having read and planned for treatment planning seminars as students. As we read the papers we rarely, if ever ask – what paper is this? An opinion, a bench study or what?
We should actively evaluate what level of evidence is being presented to us. Anything which is just a belief or opinion held to be true is simply put – a dogma. “Extension for prevention” as a principle in cavity preparation is a dogma! Until there is good evidence to support the usefulness of the idea, such as a randomised clinical trial (RCT), the idea may just be an idea, an opinion or a dogma.
Not all dogmas are bad for the patient and perhaps most dogmatic practices were birthed with good intentions. Let us take the use of the rubber dam during root canal treatment. Purportedly, rubber dams are used to reduce infection risk from exposing the root canals to saliva. Yet, there is not one randomised controlled trial to show that the use of rubber dam reduces infection; there is only one cohort study. Subjects were randomly selected from a population database of Taiwan and followed from 2005 to 2011, a total of seven years. The database has provisions for showing whether rubber dams were used or not. It was shown that the use of rubber dams gave rise to significantly better outcomes of root canal treatment (J. Endod. 2014 Nov; 40(11):1733–7).
Such a large population of 517,234 teeth may seem representative of the entire population; however, there are still things that are not clear. For instance, one does not know when one is reading the article if dentists who used rubber dams had specialist training or were supervised in teaching clinics by specialists. So, the positive outcome, whilst related to the use of rubber dam by the data, may be due to the effect of better training or better supervision among dentists who used rubber dam in that particular study. The decision of whether the use of rubber dam directly affects the outcome of root canal treatment is thus not as straightforward as it might seem.
Be that as it may, I am sure nearly all of us use the rubber dam when doing root canal treatment. It prevents the foul tasting irrigant from getting into the mouth; it prevents files from dropping into the mouth or worse, into the throat and there are risks of the instrument either being inhaled or swallowed to worry about as well. Hence, though there may not be very concrete evidence (RCT) that the use of rubber dams gives rise to a better outcome to our endodontic treatment, we continue practicing the dogma for the sake of common sense safety.
Each dogma we practice needs to be evaluated carefully, lest we incur unnecessary costs in providing care.
There are of course many procedures in our practice that are supported by evidence and are not dogma: tooth-brushing reduces gum inflammation and periodontal disease and acid etching of enamel and bonding with Bis-GMA can provide good retention for fillings, among others.
Can you identify the dogmas we practice in dentistry? There are many. After we graduate from dental schools, nearly all of us have little access to the library of information housed within universities. Most of us depend on accessing the internet for information. What your dental education must have done for you, to prepare you for your craft, must have been also to teach you how to recognise which practices are dogma and which are scientifically validated. It would have taught you to discern the nuanced statements made in guidelines to dental practice as well as to discern which articles are about ideas that are not yet validated.