Halitosis – Bad breath

Background info on bad breath or halitosis

Bad breath, also know as halitosis, occurs in everyone at some point but around 25% of the population suffer from chronic halitosis. This percentage is higher in older individuals than younger ones.  Halitosis most often starts in the mouth, studies show around 85% of the cases are from the oral cavity.   Gingivitis and periodontitis are the main causes of the problem.25  Poor oral hygiene allows food particles to collect on the surface of the tongue, between the teeth, or along the gum tissue that surrounds the teeth.  Naturally occurring bacteria in your mouth then break down those food particles, releasing chemicals that have a strong odor.

Microbial degradation of food particles produce volatile sulphur compounds (VSCs).  The most important VSCs involved in halitosis are hydrogen sulphide (H2S), methyl mercaptan (CH3SH) and dimethyl sulphide (CH3)2S.  Other molecules involved in this bacterial degradation process are: diamines (indole and skatole) or polyamines (cadverin and putrescin).  They seem play a less important role in the expression of bad breath.

oral malodor compounds

How do we discover the cause of halitosis?

This is difficult because the entire diagnosis is somewhat subjective. There are VSC machines that we discuss down below, but mostly we rely on someone smelling the breath. Kapoor 2016 has a great flowchart for the diagnosis of bad breath. Zenker’s diverticulum or hypopharyngeal diverticulum is another cause that is not mentioned below.

Halitosis diagnosis flowchart

Halitosis diagnosis

Genetic conditions can cause bad breath.

There are many genetic causes of bad breath. A defective FOM3 gene results in trimethylaminuria.

Periodontal disease and the tongue

There is a positive correlation between bad breath and periodontitis: the depth of the periodontal pockets is positively correlated to the height of the VSC concentrations in the mouth.14  A positive correlation between the depth of the pockets and the concentration of the sulphur components has also been shown.15  When tongue coating is taken into account, the correlation is even more significant.15,16 

Studies suggest bad breath is caused by tongue coating in the younger generation and by periodontitis with tongue coating in older individuals.  A clinical evaluation of malodour on 2 000 patients in Belgium, showed that 76% of these patients had oral causes: tongue coating (43%), gingivitis/periodontitis (11%) or a combination of the two (18%).18 


What causes bad breath?

Odor arises from food ingestion, smoking , alcohol consumption, extraoral sources and/or psychological conditions.  80-90% of the causes are mouth related.  Infections in the mouth, such as dental caries (tooth decay), periodontal disease or mouth sores related to other conditions may contribute to bad breath.  5% are sinus or gastrointestinal and 5% are considered other Zalewska 2012 Acta Gastroenterol  Systemic conditions, such as diabetes mellitus, uremia and kidney diseases, and hepatic diseases also cause.  It may result from infections in the nose, throat or lungs; chronic sinusitis; postnasal drip; chronic bronchitis; or disturbances in your digestive system.  The main food culprits are garlic, coffee, and onions, but excessive dairy and carbs can cause problems too.

Saliva helps wash food particles from your mouth; thus, people with a dry mouth are at an increased risk of experiencing bad breath.  Some medications, mouth breathing, allergies, and smoking all can contribute to dry mouth and thus bad breath. These are all conditions in which an ENT doctor can really help with.

It is always easy to recognize halitosis, but identifying the exact cause is more complex.  Bollen and Beikler article is great on breakdown of possible causes.  Int J Oral Sciences 2012

bad breath


How to eliminate bad breath

Since most bad breath comes from issues in the mouth your best weapon is good oral hygiene.  Cleaning your mouth reduces food residue and plaque as well as reduces the risk of developing cavities and periodontal disease.  There are not a lot of short cuts to eliminating bad breath and most of the ways to prevent and eliminate it are things you have likely heard before.

  • Get professional cleanings on a regular basis, possibly every 3 months.
  • Scrape or brush the back of your tongue.  The tongue is full of bacteria, especially in the back.  The tongue is the primary source of bad breath statistically and few clean it.
  • A tongue brush with tongue zinc paste is far more effective than a tongue scraper, which can only remove the upper surface layer of the biofilm
  • Use a mouth rinse 2-3 times a day.  Something with essential oils, chlorhexidine, chlorine dioxide, hydrogen peroxide, or cetylpyridinium chloride with zinc.  The chlorhexidine is the best but it stains teeth, especially with smokers.  Hydrogen peroxide and zinc solutions are arguably at the top as well.  Halita has several of the chemicals. Some dentists recommend Oxyfresh rinse and swallow. Others like TheraBreath.
  • Clean between your teeth once a day by using an interdental cleaner such as floss
  • Brush your teeth 2-3 times day with a fluoride-containing toothpaste.  Triclosan also helps.
  • If you have dentures, take them out at night, clean them thoroughly, and use a disinfecting soak.
  • If your problem seems to stem from a dry mouth, check out my blog on dry mouth care.
  • Chew sugar free gum.  This stimulates bodies saliva production, which is our natural way of cleaning our teeth.
  • Drink lots of water and I’ve seen Echinacea and Chamomile tea recommendations too.
  • Using a weak whitening material at night may also help – it’s basically hydrogen peroxide which kills bacteria.
  • Taking a chlorophyll product may help
  • Probiotics can also help ProBio5 is one that is apparently good

What about specific bad breath smells?

Some conditions have a specific bad smell and that may help with the diagnosis.

Bad breath smell by origin


How is bad breath detected and measured?

It is very important to first determine if bad breath is caused by something in the mouth (majority) or something non-oral.  This is accomplished very easily by comparing mouth breathing to nose breathing.  The majority of patients with non-oral halitosis have blood-borne halitosis, frequently caused by the VSC dimethyl sulfide.  This may be a sign of a serious disease.    Tangerman 2012

There are three methods of analyzing oral malodour.  Organoleptic measurement is a sensory test scored on the basis of the examiner’s perception of a subject’s oral malodour.  The problem is the testing methods are far from standardized. Aydin 2016 Comp  Gas chromatography (GC) is specific for detecting volatile sulphur compounds (VSC).  However, the GC equipment is not compact, and the procedure requires a skillful operator; therefore, it is impractical for practitioners to equip their offices for GC.  However, OralChroma advertises as a compact version and as being operating freindly.  Sulphide monitors analyze for total sulphur content of the subject’s mouth air, but most are not specific for VSC.

Yaegaki CDA


Gas chromatography and sulphide monitors (both known as halitometers)

  • OralChroma
  • Halimeter
  • Breathtron
  • TwinBreasor
  • Probe Perio
  • B/B Checker
  • BreathTracker
  • FF-2A
  • Cyranose 320

Chlorine dioxide

Shinada Trials 2010

OraCare is an example of a mouth rinse with chlorine dioxide.


vanSteenberghe J Perio 2001

Cetylpyridinium chloride with zinc

vanSteenberghe J Perio 2001


Dadamio J Perio 2013

Winkel J Perio 2003


Bad breath is a common complaint and is expereicnd by everyone at some point. Volatile sulphur compounds
(VSCs), such as hydrogen
sulfide and methyl mercaptan, have been researched extensively and are primarily responsible for bad breath.   In addition to VSCs, polyamines
such as putrescine and cadaverine may also contribute to
oral malodor.

Tongue Coating and Oral Malodor

It is a well-established fact that
tongue coating is the primary source of oral malodor, but
what influences its formation is not well understood.

Tongue coating forms for most people with or without
periodontal disease. More coating is associated with gingivitis
and periodontitis. It generally forms on the dorsum of
the tongue in varying thicknesses and colors. It consists of
bacteria, desquamated epithelial cells, blood metabolites,
food particles and leukocytes from periodontal pockets.
Anaerobic bacteria within the tongue coating breaks down
organic substances, which produces VSCs.

The presence of tongue coating appears to be related to several factors of which oral hygiene is the strongest.  Those who flossed their teeth daily, had
less tongue coating, perhaps because of more awareness of
tongue hygiene.  Smoking, use of a denture, periodontal
status, and dietary habits also correlated although less obvious. 1

The most compelling evidence was provided for chlorhexidine mouthwashes,
and those that contained a combination of cetyl pyridinum chloride and
zinc provided the best evidence profile on oral malodour. Little data
with respect to tongue coating were available, and none of the studies
showed a beneficial effect for this parameter. 1




Bad breath can be the result of conditions like pneumonia,
bronchitis, diabetes, and liver or kidney problems, but more often than not,
it’s a direct result of what’s going on in your mouth. Though you might imagine
that the food you eat goes straight from your mouth to your stomach, hips and
thighs, some of it actually hangs around between your teeth, and while it
starts to break down fairly quickly, the nourishment it offers prompts a spike
in the growth of your mouth’s ever-present bacteria, which can send you
scrambling — at least at first — for a pack of breath mints.


Next, though, you’ll be looking for a way to get rid of the
problem for good, and a tongue scraper may be part of that solution.


While regular brushing and flossing will address your teeth
and gums, they do nothing for the tongue. However, the tiny bumps and ridges
that cover the tongue’s surface provide an excellent environment for bacteria
— which create smelly volatile sulfur compounds (VSCs) like hydrogen sulfide,
methyl mercaptan and dimethyl sulfide — to thrive. Ridding your tongue of
these bacteria can go a long way toward improving your breath.


That’s where tongue scrapers come in. These small, plastic
devices feature a curved edge so that when you drag them across the top of your
tongue, they’ll scrape off the germs and bacteria that cause bad breath as they


According to WebMD, studies suggest that using a tongue
scraper is slightly more effective than brushing your tongue when it comes to
tackling problems with bad breath [source: Hitti]. But a 2004 study by
researchers at Brazil’s University of Sao Paulo showed more dramatic results: a
75 percent reduction in VSCs through tongue scraper use, compared to only a 45
percent reduction in VSCs when a toothbrush was used to clean the tongue
[source: Pedrazzi].


Using a tongue scraper is easy: Simply place it toward the
back of your tongue, and drag it forward toward the tip of your tongue. As is
the case with brushing your tongue, there won’t be any surefire way to tell
when you’re finished, other than spending a little time doing it until
satisfied. However, if you have any irritation of the tongue, cuts or open
sores, give your tongue a chance to heal before scraping it.


If bad breath persists, talk to your dentist and family
doctor. Gum disease, cavities or an undiagnosed health condition may be to
blame. And for lots more information on tongue scrapers and bad breath, please
check out the next page.



Carr, Alan, D.M.D.
“Bad breath: Could a tongue scraper help?” Mayo Clinic. May 29, 2010.
(Sept. 8, 2011)

Chicago Tribune.
“Mini-dental tools get a cautioned nod.” July 22, 2001. (Sept. 1,
2011) http://articles.chicagotribune.com/2001-07-22/news/0107220518_1_plaque-gum-tartar

“Plaque: What is it and How do We Get Rid of It?” (Sept. 1, 2011)

“What is Plaque?” (Sept. 8, 2011)

Grogan, Martha,
M.D. “Can poor oral health cause heart disease? Will taking care of my
teeth help prevent heart disease?” Mayo Clinic. Aug. 26, 2010. (Sept. 1,

Hitti, Miranda.
“Bad Breath Banishers Battle It Out.” WebMD. April 21, 2006. (Sept.
8, 2011)

Mayo Clinic.
“Oral health: Brush up on dental care basics.” Feb. 17, 2011. (Sept.
1, 2011) http://www.mayoclinic.com/health/dental/DE00003

Pedrazzi, V.
“Tongue-cleaning methods: a comparative clinical trial employing a
toothbrush and a tongue scraper.” Journal of Periodontology. July 2004.
(Sept. 8, 2011) http://www.ncbi.nlm.nih.gov/pubmed/15341360

Wall, Rachel, RDH,
BS. “How to guide your patients to the products that are right for
them.” Modern Hygienist. April 2006. (Sept. 8, 2011)

“Dental Health and Bad Breath.” Feb. 8, 2009. (Sept. 1, 2011)