This news release about a small pilot study of a brand of toothpaste that displays plaque on teeth plays up potential, but unproven benefits, while ignoring serious weaknesses in the research. The release notes the study found people using Plaque HD toothpaste for a couple of months had less plaque and lower levels of a blood protein that is associated with a type of inflammation that may, in turn, be associated with heart disease risk in certain cases. But the release does not provide any hard numbers. It doesn’t mention that inflammation levels inexplicably rose in people using the placebo toothpaste, just one of many questions about the quality of the study and the meaning of its results.
Indeed, the researchers excluded more than a third of the trial participants from the high-sensitivity C-reactive protein (hs-CRP) test analysis (hs-CRP is a measure of inflammation that is sometimes associated with cardiovascular disease risk), because their baseline results were already so low that they weren’t likely to see any further reduction. The release does not mention this important study design decision. The release does not tell readers that the study was paid for by the maker of the toothpaste brand. It does not mention other possible explanations for the results or the availability of other, much cheaper, products that also mark tooth plaque.
This small, pilot study is already being used by the maker of Plaque HD to promote its high-priced toothpaste. The company, which funded the study, improperly proclaims on the product website that the study “suggests Plaque HD reduces the risks of cardiovascular disease.” And a company news release goes even further, claiming “Toothpaste May Save Your Life.” While the company language goes far beyond the wording of the release from Florida Atlantic University that we reviewed, the academic version dovetails nicely with the study funder’s marketing. Indeed, similarities between the two releases raise troubling questions about behind-the-scene coordination between the university and the company.
We were dismayed that a major figure in epidemiology, Dr. Hennekens, would allow his name to be attached to this study or to the exaggerated claims made in the news releases and product website.
Plaque HD toothpaste is very expensive: $16.95 plus $5.75 shipping for a single 4.1-ounce tube, according to the manufacturer’s website, compared to less than $5 for a similar amount of conventional toothpaste. Also, plaque disclosing tablets can be bought for about 10 to 25 cents each. These don’t have to be used every day, just on a periodic basis to determine effectiveness of brushing.
Considering the big price difference, consumers would want to see strong evidence that this brand of toothpaste really provides health benefits over other toothpastes and other ways of showing plaque on teeth.
The release fails to quantify the observed reductions in tooth plaque and high-sensitivity C-reactive protein. Although the body of the release notes that the researchers are planning a much larger trial in order to see whether this toothpaste can reduce the risk of heart attack and strokes, the sub-heading (“Findings support reductions in heart attacks and strokes”) overstates the study conclusions.
Also, by not including the patients with low CRP levels, the results could be more impressive than if used in a larger population with patients who have elevated CRP and those who don’t.
The release does not mention harms. While regular toothpastes come with a standard warning to keep away from young children and to avoid ingesting, we aren’t told if the disclosing agents used in Plaque HD’s “Targetol technology” pose any additional harms for people with sensitivity or mouth problems. It would be good to be told either way.
The release does a poor job of describing the trial. The trial leaves many, many questions unanswered. The release fails to discuss them, except to note that a much bigger trial is in the works to test potential health benefits. For instance, neither the journal article nor the release describe the brushing technique instructions given to study participants. A description of the trial posted at ClinicalTrials.gov indicates that participants were told to brush once a day for one minute, which is less often and briefer than the twice-a-day for two minutes many dentists commonly recommend. Even the Plaque HD label recommends brushing at least twice a day. There is no indication that researchers tracked how often or how long participants actually brushed. Also, participants in this trial used manual toothbrushes, not electric ones, which in some studies seem to do a better job reducing plaque. These features of the trial are important and should have been discussed.
What if the participants using Plaque HD brushed longer than those using the placebo paste, because they could see the stained plaque that was on their teeth? Could it be that brushing frequency and duration are important variables, as some studies of oral cleanliness have found? Is it possible that simply using a timer, so that the participants using the placebo toothpaste brushed just as long, might have minimized differences between the groups?
There are some key statistics that are left unexplained in the journal article and not mentioned in the release. For instance, hs-CRP levels actually rose in the placebo group. Why? And if the levels had not changed, as would be expected, would that have wiped out the claimed advantage of Plaque HD? What’s more, the researchers excluded 23 of the 61 participants (38 percent) from the hs-CRP analysis because their baseline levels were already very low. The key study design decision is not mentioned in the release. These are all very important issues and can lead to a very biased conclusion in the study.
This release illustrates a recurring problem with disease-oriented rather than patient-oriented evidence. The release ties dental plaque and hs-CRP test levels more tightly to heart attacks and strokes than is justified. It begins by stating, “For decades, research has suggested a link between oral health and inflammatory diseases affecting the entire body — in particular, heart attacks and strokes.” But it doesn’t explain how nuanced those links are. Indeed, the value of CRP testing is hotly debated. It is typically recommended only for people having a hard time deciding whether or not to begin statin drug treatment. The release strongly (and improperly) implies that everyone, regardless of their individual heart disease risk, would benefit from something that lowers hs-CRP levels. Indeed, almost 40 percent of the trial participants were dropped from the hs-CRP comparisons because their levels were already low. If researchers decided that more than a third of the trial participants were unlikely to see any meaningful reduction in their hs-CRP levels, the release should have noted that many people have no reason to think that this product could reduce their heart disease risk.
The release fails to disclose that the trial was funded by TJA Health LLC, the maker of Plaque HD. (The journal article states that the company was not involved in the design, conduct or reporting of the trial.) And while the release devotes considerable attention to the prominent career of senior author, Charles Hennekens, MD, it does not point out that he holds patents related to CRP testing.
The release does not mention the availability of inexpensive plaque-disclosing tablets. Consumers would want to know if such tablets might be an alternative to the very pricey Plaque HD toothpaste, an important point that the study did not explore. The release also does not discuss the potential effect of brushing frequency or duration.
The release implies that Plaque HD toothpaste and testing for hs-CRP are both currently available.
The release states that “the findings on decreasing inflammation are new and novel” and “Plaque HD® is the first toothpaste that reveals plaque so that it can be removed with directed brushing.” However, the study doesn’t present strong evidence for the first claim and in regard to the second, neither the release nor the journal article address whether plaque-identifying toothpaste is superior to plaque-disclosing tablets.
As noted above, the sub-heading (“Findings support reductions in heart attacks and strokes”) overstates the conclusion of the small, pilot trial. And the release repeatedly states or implies that reducing levels of hs-CRP provides a health benefit, which is a matter of ongoing debate.
There is also no support provided for the claim that Dr. Hennekens has “saved more than 1.1 million lives.” Where does this number come from? Whatever his contributions to medical science, it is hard to imagine that he personally can claim credit for saving more than 1 million individual lives.