Intensive Care Unit

Your ICU Needs More Toothbrushes

Hospital-acquired pneumonia is disturbingly common, affecting about 1% of hospitalized patients. Hospitals have adopted all sorts of strategies to reduce these infections but we have overlooked what is arguably one of the simplest – brushing patients’ teeth.

A new study published this week in the journal JAMA Internal Medicine examined the effects of brushing patients’ teeth on the outcomes of hospital-acquired pneumonia, hospital and intensive care unit mortality, duration of mechanical ventilation, ICU and hospital lengths of stay, and use of antibiotics. This was a meta-analysis that included 15 published clinical trials in 8 different countries. There were 10,742 patients (2,033 ICU patients and 8,097 non-ICU patients); however, after adjustment for cluster analysis (by one study that randomized hospital wards, as opposed to individual patients, to intervention versus control), the total number of patients included in the meta-analysis was reduced to 2,786.


Pneumonia. Overall there was a significant reduction in hospital-acquired pneumonia in all patients randomized to toothbrushing with a risk ratio of 0.67. A similar benefit was noted in reducing pneumonia in ICU patients (risk ratio = 0.64) and patients on mechanical ventilators (risk ratio = 0.68). To put these statistics into perspective, brushing 12 patients’ teeth prevented 1 ventilator-associated pneumonia. There was no benefit to brushing teeth more frequently than twice a day. 

Mortality. There was also a statistically significant reduction in ICU mortality in patients assigned to teeth brushing, with a risk ratio of 0.81. 

Lengths of stay. There was a significant reduction in average duration of mechanical ventilation in patients randomized to toothbrushing (1.47 fewer days on the ventilator). There was also a significant reduction in average ICU length of stay (1.36 fewer days in the ICU).

Other outcomes. There was no significant reduction in total hospital length of stay but only 2 of the 15 studies reported this outcome. There was also no significant reduction in antibiotic use but only 3 of the studies reported this outcome. 


It has long been believed that oral hygiene is important in ICU patients. To date, most studies have focused on the use of chlorhexidine mouthwashes and older guidelines recommended the routine use of chlorhexidine mouthwashes in order to reduce ventilator-associated pneumonias. However, more recent studies and meta-analyses have not demonstrated a significant benefit of chlorhexidine and newer guidelines have not made recommendations regarding the use of chlorhexidine. In addition, concerns have been raised about the potential harm from drug allergy, chlorhexidine aspiration, and development of resistant bacteria.

Dentists mostly focus on the importance of toothbrushing after eating in order to reduce dental caries. But most patients in the ICU (and all intubated patients) are NPO and thus not eating. The reason to brush teeth in ICU patients is not to prevent cavities but to prevent pneumonias. Because teeth carry a large burden of oral bacteria, toothbrushing can be seen as analogous to hand washing to prevent infections.

Any study of toothbrushing is by necessity non-blinded since it is obvious to the ICU staff whether or not they are brushing their patients’ teeth for them. Therefore, this new data is not as strong as data from randomized, double-blinded, placebo-controlled clinical trials, for example in clinical trials of new experimental medications. Also, it is unclear if there is an advantage to having dental assistants versus nurses do the toothbrushing or an advantage of using a regular toothbrush versus an electric toothbrush. Similarly, it is unclear what kind of toothpaste (if any) is best. In all likelihood, any method of reducing the amount of gunk on patients’ teeth will be effective.

Toothbrushing is simple. And in the ICU, we should do it more often.

December 20, 2023

By James Allen, MD

I am a Professor Emeritus of Internal Medicine at the Ohio State University and former Medical Director of Ohio State University East Hospital