Night-time teeth brushing is associated with a significantly lower risk of developing an adverse cardiovascular event, according to the findings of a recent Japanese study.

Infrequent teeth brushing is associated with severe forms of periodontal disease. While patients with cardiovascular disease require special considerations, particularly in regard to dental treatment, it is also recognised that the odds of a cardiovascular event increases as the frequency of tooth brushing decreases.

But whether the frequency and timing of teeth brushing impact on the development of cardiovascular disease events is less clear.

In a study published in the journal Scientific Reports, Japanese researchers investigated whether the timing of toothbrushing affected cardiovascular disease risk. The research team enrolled patients 20 years of age and older, who were hospitalised for surgery, examination, or medical treatment. These individuals had visited the dentistry unit at the hospital for a variety of reasons including preoperative oral care, screening for sources of infection and requests for oral care or dental treatment.

Patients were categorised based on teeth brushing as: brushing after waking and at night (Group MN), brushing only at night (Group N), brushing only after waking (Group M), and not brushing teeth at all (Group None).

The presence of cardiovascular events, which included heart failure, myocardial infarction, arrhythmia, and angina pectoris, were investigated based on electronic medical records. Individuals were observed between April 2013 and March 2016 or until death.

Teeth brushing frequency and cardiovascular outcomes

There were 1,583 patients included in the study. Just over a quarter (25.3%) were in Group MN, and almost half (47.4%) were in Group N.

Multivariate analysis of cardiovascular events showed significantly higher survival estimates in Group MN (hazard ratio, HR = 0.59, 95% CI 0.38 - 0.92, p = 0.021). Similarly, there was higher survival in Group N (HR = 0.55, 95% CI 0.37 – 0.83, P = 0.004).

In further analysis based on smoking status, it was found that smokers in Group None had a significantly worse prognosis for cardiovascular events than smokers in other groups. In addition, non-smokers in Groups None and Group M showed significantly worse prognosis on hospitalisation.

While the researchers accepted that since their findings were based on cardiovascular disease, the results may not be generalisable, they did suggest that brushing teeth at night was important for lowering cardiovascular disease risk.