I would like to respond to Dr. Niederman’s September JADA article, "Manual Versus Powered Toothbrushes: The Cochrane Review." I feel an important factor was overlooked in all the studies, and that it illustrates a fundamental flaw in the whole concept of "evidence-based dentistry."
There was no consideration made of the manual dexterity of the people involved in any of the studies mentioned. It may seem silly to most dentists to question this factor since all of us, I presume, have a high level of manual skill. Brushing our own teeth well is hardly a challenging task.
It may be difficult to accept that such an apparently simply task can present insurmountable difficulties for many people. Yet, after 26 years of personally teaching patients to brush and floss properly, I can assure you that there is an enormous range of ability among patients. Unfortunately, I have found that, with very few exceptions, older individuals in particular cannot master effective use of the brush. Let’s not even talk about flossing. They simply cannot gain enough skill at brushing to achieve a high level of hygiene that assures freedom from recurrent dental damage.
These people are not necessarily handicapped in any way, but that can be an important issue, too. Because electric toothbrushes require less dexterity to use, I have found that their use gives these patients a much better chance to achieve a consistently high level of hygiene. However, many patients cannot manage even to use an electric brush optimally. I agree that, if used correctly, a manual brush is just as good as any electric brush. But this presumes a lot. Please do not underestimate the complexity of the required motor skill. I feel that failure to address this important variable renders the studies misleading and the conclusions pointless.
This brings me to the second point I would like to make. The term "evidence-based dentistry" should really perhaps be changed to "statistics-based dentistry." But no study involving living beings can possibly bring into account all relevant variables. Therefore, statistical analysis of treatment data is of little use.
Human beings are all individuals. On the most subtle level of mind, we are all vastly different. On the less subtle level of DNA, the differences are gross enough that DNA is virtually unique to the individual. This has to imply that, on a biochemical level, there are also great differences.
On the more gross physical level, the differences are more subtle, but are still clearly there. A health care system that does not choose to acknowledge this has a significant factor for failure built into it. It would be like expecting all people to wear the statistical average shoe size.
The art of health care is not finding which treatment works best for the most people, but which works best for each individual. The pill that heals patient A may kill patient B. This presents a very daunting puzzle that may not be possible to solve with a system that is unwilling to face the magnitude of the differences between individuals.
Statistical analysis of data will serve to obscure these important, subtle variables and render the studies misleading or worthless. I would urge great caution in offering up or choosing to use statistically analyzed results of treatment as a meaningful tool for treatment planning. It could be a help, or an elegant trap for the unwary. Statistics are not a worthy substitute for the classical scientific method.
