The effect of aspirin intake on bleeding on probing in patients with gingivitis.

Background: Bleeding indices are used as a screen for periodontal disease activity, a measure of disease prevalence, and a measure of effectiveness in clinical trials. Bleeding on probing (BOP) is widely interpreted as a sign of disease activity whereas its absence is interpreted as both a sign and predictor of health. Aspirin use has become increasingly common in the prevention of cerebrovascular and cardiovascular diseases. Because of its anti-platelet activity, aspirin is a non-disease factor that has the potential to affect the appearance of BOP. The hypothesis being tested is that short-term aspirin use in doses of 81 mg and 325 mg will increase the number of bleeding sites in a population with gingivitis.

Methods: Fifty-four subjects were screened initially, those subjects with 20% to 30% whole mouth BOP were randomly assigned to one of three arms: placebo group, 81 mg aspirin group, or 325 mg aspirin group. Before and after exposure to the respective regimens, clinical parameters were measured on all the teeth: the plaque index was recorded at four sites per tooth, and probing depth and BOP were evaluated at six sites per tooth using an automated pressure-sensitive probe.

Results: The data obtained in this clinical trial were analyzed utilizing a linear regression analysis to control for confounding variables. The primary measure of interest was BOP in patients clinically demonstrating naturally occurring gingivitis. The results of this study indicate that while controlling for age, gender, and plaque, "low dose" 81 mg and "regular dose" 325 mg of aspirin demonstrated a statistically significant 5.30 (P = 0.001) and 4.13 (P = 0.010) increase from baseline, respectively, in percent BOP.

Conclusion: Failure to consider the effects of aspirin on BOP could impair proper diagnosis and treatment planning for clinicians and introduce a significant confounding variable in research situations.