Keeping teeth squeaky clean can spare people from contracting pneumonia in hospital, a new analysis of more than 2,700 patients has found, with fewer cases of the common lung infection linked to daily toothbrushing.

Selina Ehrenzeller and Michael Klompas, two epidemiologists specializing in infectious disease at Brigham and Women's Hospital in Boston, pooled data from 15 clinical trials where people either brushed their teeth multiple times daily, or washed their mouths out with antiseptic mouthwash, swabs, or saline.

While the logic of good oral hygiene seems pretty clear – cleaning your pearly whites could stop bacteria or other pathogens sneaking down the throat to cause lung infections such as pneumonia – the evidence has so far been a bit conflicting, especially for patients in hospital who who cannot brush their teeth unassisted.

Ehrenzeller and Klompas sought to clear that up, analyzing data on 2,786 patients involved in one of 15 clinical trials and finding that hospital-acquired pneumonia rates were lower among patients randomized to daily toothbrushing, twice or more a day.