Ways dentists test for bad breath (halitosis).

- Scientific methods used by researchers and clinicians to detect and quantify halitosis. | Halimeters | Gas chromatography | Organoleptic testing | BANA test | Chemical sensors | What level of testing is really required?

Scientific testing for halitosis.

Before a research study can evaluate the effectiveness of a bad breath cure, or a dentist can determine the progress a patient has made with their condition, each needs a way to test for and quantify the patient's oral odors. This page describes some of the ways this can be accomplished.

Smell vs. more technical testing.

The first method we discuss below is organoleptic testing, which is really just a smell test. Though in a clinical setting, it is performed under conditions that are as objective and controlled as possible.

The other methods we describe, while more technical in nature in the sense that they involve the use of some type of device, have the limitation that they've usually been designed to just identify certain compounds, or types of bacteria, that are considered "usually" being associated with halitosis cases.

Of course, the question then becomes one of how important a role those particular factors play in your case.

A quick self-test may be all that you need.

We mention this because quantifying your condition may not be as important as simply identifying it as being present. After all, the same first steps are always taken with all cases.

And just a smell test can accomplish this, whether its performed by your dentist or hygienist. Or by yourself using an at-home self-evaluation methods like we describe here.

Scientific bad breath testing methods -

a) Organoleptic testing.

This is just a fancy way of saying that the tester uses their own nose to make the judgment. We mention it first because this is the oldest method of making an evaluation.

It's been used in numerous studies, and it's easy enough to see why. A human nose is always readily available, and doesn't cost anything to operate. And despite what you might think initially, it's a pretty sophisticated piece of equipment in the sense that one can detect up to 10,000 different smells.

Considerations involving the tester.


One obvious problem with organoleptic testing is that it's not totally objective in the way machine testing is. Unrelated factors might be evident to the tester and influence the outcome of their determination.

Additionally, when repeatedly exposed to a bad odor, a person's sense of smell tends to acclimate to it, and therefore loses much of its sensitivity.

(This is a biological process referred to as "adaptation." And due to it, a person's breath that seems exceedingly objectionable at the beginning of testing may seem much less so as their evaluation continues.)

Additional issues.

Another difficulty is that certain factors may influence the tester's judgment. For example, studies have shown that hunger, head position, degree of attentiveness and level of expectation may each influence the evaluation. Additionally, people who smoke, are pregnant, have chronic allergies or asthma tend not to make good judges.

Considerations involving the subject.

Factors associated with the person being tested need to be controlled for too.

  • The consumption of garlic, onions or spicy foods should be stopped 48 hours prior to testing.
  • Scented cosmetics should not be used during the preceding 24 hour period.
  • The subject should avoid consuming foods, drinks or tobacco products for 12 hours before their assessment.
  • They should also refrain from using oral rinses, breath fresheners and omit usual oral hygiene practices 12 hours prior.

Section references - Yaegaki

b) Gas chromatography.

A gas chromatograph is a scientific apparatus that can identify and precisely measure compounds in test samples, even when found in very low concentrations. The use of one of these machines is considered to be the gold standard for breath testing because the results are highly objective, reproducible and reliable.


While being a very precise method, the use of gas chromatograpy hasn't been extensively used in scientific studies.

That's because these machines are relatively expensive, they're not portable, they require special training to operate and require a significant amount of time to take each measurement. We'll also say that it's unlikely that your dentist has one.

c) Halimeters.

A halimeter is a specialized unit that's been designed specifically for breath testing. These machines (first introduced in 1991) measure for levels of sulfide gases.

(Sulfides, such as hydrogen sulfide and methyl mercaptan (collectively referred to as volatile sulfur compounds or "VSC's"), are known to be causative agents of halitosis.)

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  • Halimeters only tests for sulfides as a class and not as individual compounds.

    (In comparison, a gas chromatograph provides a breakdown of both the compounds present and their concentration.)

  • Ethanol (drinking alcohol) and essential oils, both of which are frequently found in mouthwash, can interfere with measurements.

On the plus side, a Halimeter requires no special training to use, is portable, measurements can be made quickly and the device is comparatively inexpensive. Dentists who take a special interest in treating halitosis cases often have one in their office.

d) Chemical sensors.

As a way of improving sensitivity (as compared to a Halimeter), and providing greater convenience for the dentist (as compared to a gas chromatograph), chemical sensors have been developed for halitosis testing.

This type of device, sometimes referred to as an "electronic nose," takes the form of a probe that can be used to take readings from both the surface of the tongue and below the gum line (the two areas most associated with bad breath).

Newer types of sensors can measure multiple types of sulfur-containing compounds separately (an improvement over Halimeter technology).

e) The BANA test.

Some of the types of bacteria that cause periodontal disease (gum disease) also produce smelly waste products that cause bad breath. The BANA test is a simple way a dentist can check for the presence of these types of bacteria, by way of testing a sample of their patient's saliva, dental plaque or a tongue swab.

The types of bacteria in question produce an enzyme that degrades the compound benzoyl-D, L-arginine-naphthylamide (abbreviated BANA). When this reaction occurs, it produces a color change in the BANA test strip.

Section references - (Primary source for all of the scientific methods described above.) - Aylikci

Our next page explains what the odors you smell are and where they come from. Once you know that, you'll know how to cure your problems.