09:26pm Wednesday 23 October 2019

Learning to sniff bad breath can help diagnose oral disease

According to the microbiologists running the course, bad breath – or oral malodour – is the third most common reason for people to visit their dentists. However dentists are not trained to distinguish the causes of oral malodour using their sense of smell.

Professor John Greenman runs the course with Dr Saliha Saad who is a trained oral malodour judge. They point out that smells on the breath come from either microbes or the metabolism of the body. In 80% of cases, bad breath is due to microbes in the mouth, and not to conditions elsewhere in the body. Oral malodour could be caused by microbes on the tongue, inflammation of the gums or tooth decay. These conditions give off specific smells which a trained ‘nose’ can detect, differentiate and then treat appropriately.

The course is aimed at doctors, dentists, hygienists, nurses and technicians and will train participants to recognise and identify the main groups of malodour compounds that occur on breath of individuals.  

The five-day step-by-step course starts with training participants’ noses by getting them to smell dozens of chemical odours and asking them to score them in order of increasing strength. This familiarises them with the type of smells likely to be found in breath. Then they go on to sniff the breath of human volunteers and learn how to score it using two scoring methods.

These are the organoleptic method, which scores the intensity of the odour on a scale of 0-5, and the hedonic method, which assesses the ‘quality’ of the smell in terms of pleasant or unpleasant and by comparing it in their minds with familiar odours such as eggs, cabbage, flowers etc.

On the third day participants would be introduced to instrumental methods for detecting malodour and the different oral hygiene means and chemoprevention such as cleaning the tongue, dental flossing and use of mouthwash then retesting the patient’s breath to see if this had solved the issue.

Dr Saad said, “The complaint of bad breath usually comes from the patient, but often dental staff are not trained to deal with the issue. They need to distinguish between odours that are present on the ‘mouth’ breath, which can be caused by microbes on the tongue, gum disease or tooth decay, all of which can be easily treated, and with volatiles carried on breath from the lungs that could denote more serious diseases or organ failure.

“Before people can go on the course, we screen them to find out that they have the correct smell receptors in their nasal epithelium– some people are scent-blind, or anosmic. People need to score 80% or more in the screening test to benefit from the course. Then we can help them to use their brain to separate and understand the smells they are experiencing. We also teach them how to use analytical instruments such as a halimeter and oral gas chromatography. This course puts together the knowledge with the ability to use instruments – dental professionals shouldn’t rely on one method alone although the nose is the gold standard! ”

John and Saliha’s work on microbes and their odours has other health applications for example in dealing with infected wounds.

The next UWE oral malodour course starts on 3 September  – participants come from all over the world including the USA, the Middle-East and Europe and include academics as well as medical and dental professionals. 

For more information on the course email saliha.saad@uwe.ac.uk





Contact Details


Jane Kelly or Mary Price, Media Relations Office

UWE Bristol

Tel: 0117 32 82208

Share on:

MORE FROM Oral and Dental Health

Health news