Researchers from Cardiff University, UK, began by taking mouth, tongue and denture swabs from a group of patients in hospital who had pneumonia and wore dentures. They then compared this to samples taken from denture-wearing patients in care homes who did not have pneumonia.

They then analysed the samples to identify the abundance and types of microbes present in the samples. Researchers were looking for microbes that could cause pneumonia and whether there were any significant differences between the two groups.

"We were expecting to see a difference but were surprised to see 20 times the number of potentially pneumonia-causing bacteria on dentures in people with pneumonia, compared to people without." said Dr Josh Twigg, lead author of the study.

Dr Twigg and his team speculate that the dentures could play a role in causing pneumonia. If they are not cleaned properly, they could provide a new surface where disease-causing microbes can colonise. People who wear dentures may then be aspirating (inhaling) saliva containing harmful microbes into their lungs, where an infection can then take hold.

However, while this study identifies a possible connection, Dr Twigg stresses "You certainly couldn't say that people got pneumonia because they were wearing dentures. It's just showing that there is an association there. This research is an early step in trying to unravel that puzzle of what exactly is the sequence of events".

While more research needs to take place, the public can still learn from the findings, according to Dr Twigg. "Our research has shown that there are potentially harmful microbial communities on dentures. It is important to clean dentures thoroughly". By attending the dentist regularly for check-ups and learning about the best way to look after your teeth, Dr Twigg hopes that more people will avoid needing to wear dentures entirely.

For anyone interested in learning more about keeping a healthy mouth and teeth, Dr Twigg recommends the Oral Health Foundation.