Bad breath

Bad breath, also known as halitosis, is a

The concerns of bad breath may be divided into genuine and non-genuine cases.[2] Of those who have genuine bad breath, about 85% of cases come from inside the mouth.^[1] The remaining cases are believed to be due to disorders in the nose, sinuses, throat, lungs, esophagus, or stomach.^[3] Rarely, bad breath can be due to an underlying medical condition such as liver failure or ketoacidosis.^[2] Non-genuine cases occur when someone complains of having bad breath but other people cannot detect it.^[2] This is estimated to make up between 5% and 72% of cases.^[2]

The treatment depends on the underlying cause.

In about 90% of genuine halitosis cases, the origin of the odour is in the mouth itself.[5] This is known as intra-oral halitosis, oral malodour or oral halitosis.

The most common causes are odour producing

The most common location for mouth-related halitosis is the

Other less common reported causes from within the mouth include:[12]^[13][14]

• Deep carious lesions (dental decay) – which cause localized food impaction and stagnation
• Recent dental extraction sockets – fill with blood clot, and provide an ideal habitat for bacterial proliferation
• Interdental food packing – (food getting pushed down between teeth) - this can be caused by missing teeth, tilted, spaced or crowded teeth, or poorly contoured approximal
  dental fillings
  . Food debris becomes trapped, undergoes slow bacterial putrefaction and release of malodourous volatiles. Food packing can also cause a localized periodontal reaction, characterized by dental pain that is relieved by cleaning the area of food packing with interdental brush or floss.
• Acrylic dentures (plastic false teeth) – inadequate denture hygiene practises such as failing to clean and remove the prosthesis each night, may cause a malodour from the plastic itself or from the mouth as microbiota responds to the altered environment. The plastic is actually porous, and the fitting surface is usually irregular, sculpted to fit the edentulous oral anatomy. These factors predispose to bacterial and yeast retention, which is accompanied by a typical smell.
• Oral infections
• Oral ulceration
• Fasting
• Stress or anxiety
• Menstrual cycle – At mid cycle and during menstruation, increased breath VSC were reported in women.
• Smoking – Smoking is linked with periodontal disease, which is the second most common cause of oral malodour. Smoking also has many other negative effects on the mouth, from increased rates of dental decay to
  premalignant lesions and even oral cancer
  .
• Alcohol
• Volatile foods  – e.g. onion, garlic, durian, cabbage, cauliflower and radish. Volatile foodstuffs may leave malodourous residues in the mouth, which are the subject to bacterial putrefaction and VSC release. However, volatile foodstuffs may also cause halitosis via the blood borne halitosis mechanism.
• Medication – often medications can cause xerostomia (dry mouth) which results in increased microbial growth in the mouth.

Nose and sinuses

In this occurrence, the air exiting the

In the case of allyl methyl sulfide (the byproduct of garlic's digestion), odour does not come from the stomach, since it does not get metabolized there.

Systemic diseases

There are a few systemic (non-oral) medical conditions that may cause foul breath odour, but these are infrequent in the general population. Such conditions are:^[17][18]

1. Fetor hepaticus: an example of a rare type of bad breath caused by chronic liver failure.
2. Lower respiratory tract infections (bronchial and lung infections).
3. Kidney infections and kidney failure.
4. Carcinoma.
5. Trimethylaminuria ("fish odour syndrome").
6. Diabetes mellitus
   .
7. Metabolic conditions, e.g. resulting in elevated blood dimethyl sulfide.^[19]

Individuals affected by the above conditions often show additional, more diagnostically conclusive symptoms than bad breath alone.

Delusional halitosis

One quarter of the people seeking professional advice on bad breath have an exaggerated concern of having bad breath, known as halitophobia, delusional halitosis, or as a manifestation of the olfactory reference syndrome. They are sure that they have bad breath, although many have not asked anyone for an objective opinion. Bad breath may severely affect the lives of some 0.5–1.0% of the adult population.^[20]

Diagnosis

Self diagnosis

Scientists have long thought that smelling one's own breath odour is often difficult due to acclimatization, although many people with bad breath are able to detect it in others. Research has suggested that self-evaluation of halitosis is not easy because of preconceived notions of how bad we think it should be. Some people assume that they have bad breath because of bad taste (metallic, sour, fecal, etc.), however bad taste is considered a poor indicator.

Patients often self-diagnose by asking a close friend.^[21]

One popular home method to determine the presence of bad breath is to

If bad breath is persistent, and all other medical and dental factors have been ruled out, specialized testing and treatment is required. Hundreds of dental offices and commercial breath clinics now claim to diagnose and treat bad breath.^[citation needed] They often use some of several laboratory methods for diagnosis of bad breath:

• mercaptan) are not recorded as easily and can be misrepresented in test results. Certain foods such as garlic and onions produce sulfur in the breath for as long as 48 hours and can result in false readings. The Halimeter is also very sensitive to alcohol, so one should avoid drinking alcohol or using alcohol-containing mouthwashes for at least 12 hours prior to being tested. This analog machine loses sensitivity over time and requires periodic recalibration to remain accurate.^[22]
• methyl mercaptan, and dimethyl sulfide
  ). It is accurate in measuring the sulfur components of the breath and produces visual results in graph form via computer interface.
• BANA test: this test is directed to find the salivary levels of an enzyme indicating the presence of certain halitosis-related bacteria.
• β-galactosidase
  test: salivary levels of this enzyme were found to be correlated with oral malodour.

Although such instrumentation and examinations are widely used in breath clinics, the most important measurement of bad breath (the gold standard) is the actual sniffing and scoring of the level and type of the odour carried out by trained experts ("organoleptic measurements"). The level of odour is usually assessed on a six-point intensity scale.^[3][6]

Classification

Several classification schemes have been proposed to define halitosis.^[24]

Miyazaki et al.

The Miyazaki et al. classification was originally described in 1999 in a Japanese scientific publication,^[25] and has since been adapted to reflect North American society, especially with regards halitophobia.^[26] The classification assumes three primary divisions of the halitosis symptom, namely genuine halitosis, pseudohalitosis and halitophobia.

• Genuine halitosis
  • A. Physiologic halitosis
  • B. Pathologic halitosis
    • (i) Oral
    • (ii) Extra-oral
• Pseudohalitosis
• Halitophobia

This classification has been criticized for being inflexible, and that the pseudohalitosis and halitophbia categories contain psychopathologic connotations.^[24]

Tangerman and Winkel

The Tangerman and Winkel classification was suggested in Europe in 2002.^[27][19] This classification focuses only on those cases where there is genuine halitosis, and has therefore been criticized for being less clinically useful for dentistry when compared to the Miyazaki et al. classification.

• Intra-oral halitosis
• Extra-oral halitosis
  • A. Blood borne halitosis
    • (i) Systemic diseases
    • (ii) Metabolic diseases
    • (iii) Food
    • (iv) Medication
  • B. Non-blood borne halitosis
    • (i) Upper respiratory tract
    • (ii) Lower respiratory tract

The same authors also suggested that halitosis can be divided according to the character of the odour into 3 groups:^[19]

• "Sulfurous or fecal" caused by
  methyl mercaptan, hydrogen sulfide and dimethyl sulfide
  .
• "Fruity" caused by acetone, present in diabetes.
• "Urine-like or ammoniacal" caused by
  dimethyl amine and trimethylamine (TMA), present in trimethylaminuria and uremia
  .

Based on the strengths and weaknesses of previous attempts at classification, Aydin and Harvey-Woodworth proposed a cause-based classification.[24]

• Type 0 (physiologic)
• Type 1 (oral)
• Type 2 (airway)
• Type 3 (gastroesophageal)
• Type 4 (blood-borne)
• Type 5 (subjective)

Any halitosis symptom is potentially the sum of these types in any combination, superimposed on the physiologic odour present in all healthy individuals.^[24]

Management

Approaches to improve bad breath may include physical or chemical means to decrease bacteria in the mouth, products to mask the smell, or chemicals to alter the odour creating molecules.

If diseases outside of the mouth are believed to be contributing to the problem, treatment may result in improvements.[1]

It is difficult for researchers to make estimates of the prevalence of halitosis in the general population for several reasons. Firstly, halitosis is subject to societal taboo and stigma, which may impact individuals' willingness to take part in such studies or to report accurately their experience of the condition. Secondly, there is no universal agreement about what diagnostic criteria and what detection methods should be used to define which individuals have halitosis and which do not. Some studies rely on self reported estimation of halitosis, and there is contention as to whether this is a reliable predictor of actual halitosis or not. In reflection of these problems, reported epidemiological data are widely variable.[34]

History, society and culture

The earliest known mention of bad breath occurs in ancient Egypt, where detailed recipes for toothpaste are made before the Pyramids are built. The 1550 BC Ebers Papyrus describes tablets to cure bad breath based on incense, cinnamon, myrrh and honey.^[35] Hippocratic medicine advocated a mouthwash of red wine and spices to cure bad breath.^[36] Alcohol-containing mouthwashes are now thought to exacerbate bad breath as they dry the mouth, leading to increased microbial growth. The Hippocratic Corpus also describes a recipe based on marble powder for females with bad breath.^[37] The Ancient Roman physician Pliny wrote about methods to sweeten the breath.^[38]

Ancient Chinese emperors required visitors to chew

In B. G. Jefferis and J. L. Nichols' "Searchlights on Health" (1919), the following recipe is offered: "[One] teaspoonful of the following mixture after each meal: One ounce chloride of soda, one ounce liquor of potassa, one and one-half ounces phosphate of soda, and three ounces of water."

In the present day, bad breath is one of the biggest social taboos. The general population places great importance on the avoidance of bad breath, illustrated by the annual $1 billion that consumers in the United States spend on deodorant-type mouth (oral) rinses, mints, and related over-the-counter products.^[13] Many of these practices are merely short term attempts at masking the odour. Some authors have suggested that there is an evolutionary basis to concern over bad breath. An instinctive aversion to unpleasant odours may function to detect spoiled food sources and other potentially invective or harmful substances.^[39] Body odours in general are thought to play an important role in mate selection in humans,^[40] and unpleasant odour may signal disease, and hence a potentially unwise choice of mate. Although reports of bad breath are found in the earliest medical writings known, the social stigma has likely changed over time, possibly partly due to sociocultural factors involving advertising pressures. As a result, the negative psychosocial aspects of halitosis may have worsened, and psychiatric conditions such as halitophobia are probably more common than historically. There have been rare reports of people committing suicide because of halitosis, whether there is genuine halitosis or not.

Etymology

The word halitosis is derived from the Latin word halitus, meaning 'breath', and the Greek suffix -osis meaning 'diseased' or 'a condition of'.^[41] With modern consumerism, there has been a complex interplay of advertising pressures and the existing evolutionary aversion to malodour. Contrary to the popular belief that Listerine coined the term halitosis, its origins date to before the product's existence,^[42] being coined by physician Joseph William Howe in his 1874 book The Breath, and the Diseases Which Give It a Fetid Odor,^[43][44] although it only became commonly used in the 1920s when a marketing campaign promoted Listerine as a solution for "chronic halitosis". The company was the first to manufacture mouth washes in the United States. According to Freakonomics:

Listerine "...was invented in the nineteenth century as powerful surgical antiseptic. It was later sold, in distilled form, as both a floor cleaner and a cure for gonorrhea. But it wasn't a runaway success until the 1920s, when it was pitched as a solution for "chronic halitosis"— a then obscure medical term for bad breath. Listerine's new ads featured forlorn young women and men, eager for marriage but turned off by their mate's rotten breath. "Can I be happy with him in spite of that?" one maiden asked herself. Until that time, bad breath was not conventionally considered such a catastrophe, but Listerine changed that. As the advertising scholar James B. Twitchell writes, "Listerine did not make mouthwash as much as it made halitosis." In just seven years, the company's revenues rose from $115,000 to more than $8 million."^[45]

Alternative medicine

According to traditional