Inside Dental Assisting
May/Jun 2012
Volume 8, Issue 3

Oral Malodor

Help patients understand how to recognize, prevent, and treat this common condition

Halitosis or oral malodor is a distressing complaint for patients. Fortunately, there is much that can be done to prevent or alleviate this issue, once the causes are fully understood (Table 1).

Among the common methods to combat oral malodor—for example, after using tobacco products or eating foods that include onion or garlic—are mints, mouth sprays, mouthwash, or gum. However, these methods only temporarily mask the odors created by bacteria on the tongue. In addition, when the condition is chronic and unrelated to these common sources, it is important to look into other causes, including underlying diseases, poor oral hygiene, or the dry mouth condition known as xerostomia.

Temporary or Chronic

Temporary oral malodor can be caused by normal physical functions or lifestyle choices, including the lack of salivary flow during sleep, hunger, food debris, smoking, foods such as onions and garlic, and the use of prescription drugs.1

On the other hand, chronic oral malodor originates from conditions such as poor dental hygiene, food particles in the teeth, periodontal disease, coating on the tongue, wearing dentures overnight, dry mouth, defective restorations, mucositis from radiation therapy, and Sjögren’s syndrome.1 Other medical conditions that can cause oral malodor include respiratory infections, diabetes, gastrointestinal disorders, liver disorders, and kidney disorders. In addition, xerostomia—dry mouth—can lead to halitosis, because there is less saliva to wash away the debris that produces bacteria.

Halitosis can be a precursor of serious—even emergent—medical conditions. Specific characteristic breath odors should prompt immediate medical attention. A fruity odor is a sign of ketoacidosis, which may occur in people with diabetes. Similarly serious can be a bowel obstruction signaled by breath that smells like feces, or chronic kidney failure that may be diagnosed by breath with an ammonia odor.3

Prevention and Treatment

The surest way to prevent temporary halitosis due to lifestyle choices is avoidance of the behavior. Tobacco use—even smokeless tobacco—can contribute to bad breath, as can foods such as onions and garlic, which are absorbed into the bloodstream, transferred into the lungs, and then expelled during exhalation until they are eliminated from the body.

When the cause is poor oral healthcare, steps should be taken to ensure proper brushing—making sure to include the tongue2—and flossing. Routine exams, too, are necessary to keep the mouth healthy and clean, and to rule out any disease that may cause oral malodor.

Oral malodor can be prevented or minimized by following practices that can keep the mouth hydrated and reduce bacteria.4 In addition to following professional oral hygiene recommendations, avoiding tobacco use, and seeking treatment for gum diseases, recommendations include eating a healthy, balanced diet; reducing alcohol and caffeine intake; drinking plenty of fluids; reducing consumption of sugary foods and drinks (which can lead to an increase in bacteria); chewing sugar-free gum after eating; brushing the tongue, (taking care to brush to the back of the tongue); and using a mouthrinse before retiring for the night.

In addition, products with antimicrobial components may be recommended to patients for use at home: for example, mouthwashes containing cetylpyridinium chloride, chlorhexidine, triclosan, quaternary ammonium compounds, benzalkonium chloride hydrogen peroxide, sodium bicarbonate, zinc salts, or essential oils.1

Methods to Assess Oral Malodor

Portable Sulfide Meter

Patients exhale through a tube connected to the machine, and the meter records a score based on volatile sulfur compound levels (normal, weak, or strong). One disadvantage of using this instrument is that it does not differentiate between various sulfide-containing compounds and may underestimate oral malodor in certain cases.1

Gas Chromatography

Gas chromatography measures the amount and type of volatile sulfur compounds (VSC) and volatile organic compounds (VOC) from samples of oral cavity breath. The VOCs are extracted from breath samples onto sorbant traps, identified by computer-based libraries, and quantified. This procedure is not common chairside because it is expensive and lengthy.1

Portable Gas Chromatography

To measure concentrations of VSCs in patients, a portable GC device can be used. A sample is taken by a syringe (without a needle) placed deep into the oral cavity. This sample is injected into the machine and automatically measured. This procedure is more cost-effective and less time-consuming for a practice.1

Electronic Nose

The electronic nose is a handheld instrument that uses a chemical sensor system for odor discrimination. The mouth-air gas from a patient is trapped in a tube and driven up a sensor section; an estimated VSC concentration and organoleptic score is calculated. This procedure has made odor analysis fast, simple, and cost-effective.1


The treatment or prevention of temporary odor malodor may be as simple as a lifestyle change or a mouthrinse. However, it is essential to allow patients to feel comfortable to discuss their concerns and seek treatment, as chronic malodor may indicate other underlying health issues.


1. Nachnani S. Oral malodor: causes, assessment, and treatment. Compend Contin Educ Dent. 2011;32(1):22-34.

2. Berger EK. What’s to blame for bad breath? Inside Dental Hygiene. 2006;June. https://www.insidedentalhygiene.com/article.php?id=1351. Accessed August 24, 2011.

3. Breath odor. https://www.nlm.nih.gov/medlineplus/ency/article/003058.htm. Accessed August 24, 2011.

4. Preventing bad breath. https://www.nhs.uk/conditions/bad-breath/pages/prevention.aspx. Accessed August 24, 2011.

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