BY LYNNE SLIM, RDH, BSDH, MSDH
I was in a state of euphoria during much of August, mainly because I watched the live television coverage of the Olympics in London. Having lived in England, I rooted for many of the UK athletes. British patriotism is back in fashion — flags flying everywhere. The red, white, and blue Union Jack is even showing up in the UK in the form of nail art. Not all Brits are happy about this reawakened patriotism, however, and that’s also typically British. The Brits, I have discovered, are sometimes happiest when they can debate for and against something, just as they do in parliament.
I wasn’t surprised to find a news article during the Olympics on questions about the value of sports drinks. The headline of “Gym and tonic — doubts about sport drinks” really amused me. According to the report, research “pours cold water” on the alleged benefits of sports drinks and even went as far as to say that the beverages are a waste of money. The article was based on evidence-based research, and researchers challenged advertising claims that these products lead to enhanced performance or recovery. They also pointed out that three out of six clinicians responsible for developing the 2007 U.S. guidelines on sports and hydration had financial links to sports drinks companies.
So what kind of evidence was gathered by these Oxford researchers on sports drinks, and what question did they want answered? Just as we now do in dentistry with dental product, equipment, or technology claims, it was a systematic assessment of the claims for improved sports performance made by advertisers for a range of sports-related products. The researchers looked at the quality of the evidence on which these claims were based.
IS THERE A RISK FACTOR FOR STROKES?
On a typical Monday morning, you enter an operatory to find one of your poorly compliant patients, age 58, seated in the chair. She has a history of generalized aggressive periodontitis and she tells you she recently had a stroke, eight months ago. After reviewing her medical history and verifying blood pressure of 117/65, you realize there are no obvious risk factors for stroke. In your mind, you ask yourself a simple question based on what you’ve recently read in leading dental magazines about the perio/cardio link: “Does periodontal treatment modify or lower the risk of stroke?”
In the case of sports drink products, authors identified over 400 performance-enhancing claims after reviewing over a thousand web pages, and they even found references to support these claims. After conducting a critical appraisal of the references cited, over 80 percent of the studies cited were found to be poorly designed and at high risk of bias.
So, where do you start to evaluate the evidence about the link you are questioning? Are there systematic reviews (a higher level of evidence than a single study) on the perio/stroke link? Do you often feel frustrated about knowing whom to ask, and whose information to trust on certain topics?
If you’re like me, I get frustrated when I’m presented with conflicting information. As a writer, I am constantly searching for the truth, and it just so happens I was recently part of a team of dental hygienists who critically appraised the literature surrounding several oral/systemic links, one of which was the perio/stroke link.1
Our team was led by Frieda Pickett, RDH, MS, and several members of the team were professors in U.S. dental hygiene programs. We made a decision early on not to accept corporate sponsorship for our efforts, and it was the Canadian Journal of Dental Hygiene (CJDH) that was interested in publishing our papers without any sponsorship money. An entire issue of CJDH (May 2012) was dedicated to these reviews, and the following oral/systemic links were explored:
- Diabetes (bidirectional relationship between perio/diabetes)
- Perio/respiratory disease
- Perio/systemic inflammatory diseases of obesity, arthritis, Alzheimer’s, and renal diseases
- Perio/cardiovascular diseases and stroke.
The team critically appraised the literature primarily from systematic reviews and meta-analyses, discussed the strength of the statistical support of information, and summarized the evidence.
Frieda examined the evidence for the link between chronic periodontal inflammation and cerebrovascular disease (stroke). She conducted her literature search through PubMed using MeSH terms of stroke, cardiovascular and periodontal disease, and oral-systemic relationship. Searching PubMed is relatively simple once you complete an online tutorial; MeSH
is like a vocabulary thesaurus that helps you to search at various levels of specificity. In her search, Frieda found a few systematic reviews since 2003 and a consensus literature review by the European Society of Cardiology.
Epidemiological studies link systemic inflammation to atherosclerosis and cardiovascular events like stroke but there are several common risk factors for cardiovascular disease (including stroke) and periodontal disease (smoking, diabetes, chronic inflammation) that can act equally on both diseases providing a pathophysiologic link without having a direct causal link.1
The European Society of Cardiology, in examining the perio/cardio link concluded that even though there is a statistically significant epidemiological association between periodontal and cardiovascular disease, including strokes, there is no compelling evidence that periodontal intervention will influence cardiac health. They also emphasized that research should continue to clarify the role of various biologic factors in the pathogenesis of cardiovascular disease when periodontal disease is present. In addition, they stated a worthwhile goal should be to promote periodontal health to possibly improve cardiovascular health.1
An important clinical implication mentioned in Frieda’s narrative review included information about safety in delivering care to a stroke patient. When history of a stroke is reported, periodontal therapy and other dental procedures can be provided six months following the stroke with approval by the cardiologist.1 Frieda also recommended to advise patients that much is yet unknown regarding the effects of periodontal disease as a cause of cerebrovascular disease, even though oral health is considered important for overall health. The associations between perio/stroke appear to be modest but may provide a mild influence of chronic oral inflammation on carotid or cerebral inflammation. There is no compelling evidence that preventive periodontal care or periodontal treatment will influence vascular health.1
The American Heart Association also weighed in with their recent scientific statement on the relationship between atherosclerotic vascular disease (ASVD) and periodontal disease.2 Like Frieda and the European Society of Cardiology, they concluded that there are significant gaps in our scientific understanding of the interactions of oral health and ASVD. Although they noted there is evidence from trials revealing an independent association of PD with CVD, it is important to note this association is weak (24% to 35% increase in risk of CHD).3 All of these resources stated the importance of examining well-designed, controlled interventional studies.
I was part of the Frieda Pickett team who wrote about oral/systemic links in the CJDH. I coauthored a narrative review on the perio/cardio link, and my coauthor is a periodontal researcher from Athens, Greece. I could not have written this review on my own because there is just too much data to analyze. My coauthor has prepared systematic reviews, and he was willing to spend the countless hours required to critically assess the literature. It’s an incredibly complex task, and I applaud anyone who undertakes it.
The perio/cardio link, including stroke, is a topic that one cannot tackle alone. Continued critical analysis of this independent statistical association requires a dedicated team of qualified evidence-based professionals with the appropriate credentials in a variety of disciplines.
Be wary of those who claim to be authoritative figures on this particular topic (including professional associations) because, like the sports drink industry, there have been a lot of advertising/marketing claims surrounding these links.
Frieda, like me, believes that oral health-care professionals are scientists, too, and she emphasizes the responsibility of a scientific practitioner to use the highest level of science as the basis for clinical decisions, client health information, and personal beliefs. RDH
1. Pickett FA. State of evidence: chronic periodontal disease and stroke. Can J Dent Hygiene 2012; 46, no.2: 124-128.
3. Humphrey LL et al. Periodontal disease and coronary heart disease incidence: A systematic review and meta-analysis. Journal of General Internal Medicine. 2008; 23: 2079.
4. European guidelines on cardiovascular disease prevention in clinical practice. The fifth joint task force of the European Society of Cardiology and Other Societies on cardiovascular disease prevention in clinical practice. Eur Heart J (2012) 33: 1635-1701. http://www.escardio.org/guidelines-surveys/esc-guidelines/GuidelinesDocuments/guidelines-CVD-prevention.pdf.
LYNNE SLIM, RDH, BSDH, MSDH, is an award-winning writer who has published extensively in dental/dental hygiene journals. Lynne is the CEO of Perio C Dent, a dental practice management company that specializes in the incorporation of conservative periodontal therapy into the hygiene department of dental practices. Lynne is also the owner and moderator of the periotherapist yahoo group: www.yahoogroups.com/group/periotherapist. Lynne speaks on the topic of conservative periodontal therapy and other dental hygiene-related topics. She can be reached at [email protected] or www.periocdent.com.
Past RDH Issues