Dental Scaling and Risk Reduction in Infective Endocarditis: A Nationwide Population-Based Case-Control Study

Background: Infective endocarditis (IE) is an uncommon but potentially life-threatening disease. Poor oral hygiene has been assumed as an important risk factor for IE. We aimed to investigate whether the improvement of oral hygiene through dental scaling could reduce the risk of IE. Methods: From January 1, 2000 to December 31, 2009, a total of 736 patients with newly diagnosed IE were identified from the National Health Insurance Research Database. On the same date of enrollment, 10 patients (without IE) with matched age, sex, and underlying diseases were selected to be the control group for each study patient. The frequency of dental scaling before the enrollment was analyzed and compared between the study and the control groups. Results: The percentages of patients who ever received dental scaling before the enrollment were higher in the control group than that in the study group. For patients who received dental scaling once in 2 years, the risk of IE can be reduced by about 15% (odds ratio, 0.845; 95% confidence interval, 0.693-1.012) with a borderline P value (P = 0.058). Moreover, the risk of IE decreased significantly among patients who received dental scaling at least once per year, with an odds ratio of 0.696 (95% confidence interval, 0.542-0.894; P = 0.005). Conclusions: Improvement of oral hygiene by dental scaling may reduce the risk of IE. More frequent and regular dental scaling (at least once per year) was associated with a significant decrease in IE.