The researchers believe inflammation is the link, with bacteria seeping into the bloodstream from a infection around the area of a tooth (periodontal infection). The bacteria may build up in the blood vessels, resulting in inflammation - this type of inflammation increases the risk of stroke or heart attack.
Lead researcher, Caroline Minassian, MSc, from the London School of Hygiene and Tropical Medicine, says that their findings provide more compelling evidence linking acute inflammation with cardiovascular events (e.g. heart attack or stroke).
The researchers stress that the enduring benefits of the dental treatment are greater than the temporary risk of adverse effects.
They gathered data from the U.S. Medicaid claims database involving 32,060 adults who had had a stroke or heart attack. They then traced their medical histories back to determine how many had undergone invasive dental surgery. 525 individuals had had a heart attack and 650 a stroke, all of them after dental surgery. They factored in variables which may on their own or in combination raise stroke and heart attack risk, such as hypertension (high blood pressure), diabetes, coronary artery disease, or individuals with prescriptions for antiplatelet or salicylate drugs before treatment.
The investigators discovered that there was a significantly increased heart attack or stroke risk during the month following their dental work (incidence ratio 1.50; 95% CI 1.09-2.06). One third of the vascular events occurred in patients less than fifty years of age. The risk was found to gradually subside to baseline (normal) after about six months.
Dr Liam Smeeth, from the London School of Hygiene and Tropical Medicine, said:
Many people who are only at moderate risk most of the time will enter periods of very high risk intermittently in response to inflammatory or infectious triggers due to surgery, and those people might benefit from short periods of prophylactic (preventive) therapy that most of the time they don't need.
The authors concluded:
Invasive dental treatment may be associated with a transient increase in the risk for vascular events. However, the absolute risks are minimal, and the long-term benefits on vascular health will probably outweigh the short-lived adverse effects.
Dr. Howard Weitz and Dr. Geno Merli , from Jefferson University, Philadelphia believe the link between inflammation markers and atherosclerosis is still a tenuous one. They add that Minassian et al did not have enough data to associate a vascular event risk with inflammation.
Weitz and Merli state that the study has a serious limitation - the Medicaid data did not have details on patients' aspirin therapy or cessation before their dental surgery. Aspirin cessation has been shown to be a possible trigger for cardiovascular events. A proportion of patients (15%) stop taking aspirin before dental surgery and then go on to have a cardiovascular event.
A cardiovascular event is a set of outcomes related to blood vessels and/or the heart, such as a heart attack.
A vascular event is a set of outcomes related to blood vessels, such as a stroke, which used to be known as a cerebrovascular accident.
"Invasive Dental Treatment and Risk for Vascular Events - A Self-Controlled Case Series"
Caroline Minassian, MSc; Francesco D'Aiuto, PhD; Aroon D. Hingorani, PhD; and Liam Smeeth, PhD
Annals of Internal Medicine. October 19, 2010 vol. 153 no. 8 499-506
Written by Christian Nordqvist