DefinitionBreath odor can be defined as the subjective

perception after smelling someone’s breath. It canbe pleasant, unpleasant or even disturbing, if notrepulsive. If unpleasant, the terms breathmalodor, halitosis, bad breath, or fetor ex ore canbe applied.

The term “oral malodor” is thus too restrictive.Breath malodor should not be confused with themomentarily disturbing odor caused by foodintake (e.g., garlic, onions, and certain spices),smoking, or medication (e.g., metronidazole)

because these odors do not reveal a healthproblem. The same is true for “morning” badbreath, as habitually experienced on awakening.This malodor is caused by a decreased salivaryflow and increased putrefaction during the nightand spontaneously disappears after breakfast ororal hygiene measures.

Epidemiology Breath malodor is a common complaint among the

general population. It has a significantsocioeconomic impact .

Almost $1 billion a year is spent in the United Stateson deodorant-type mouth (oral) rinses, mints, andrelated over-thecounter products to manage badbreath. It would be preferable to spend this moneyon a proper diagnosis and etiologic care instead ofshort-term and even inefficient masking attempts.

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CLASSIFICATION Genuine halitosis : when the breath malodor really

exists and can be diagnosed or organoleptically orby measurement of the responsible compounds.

Pseudo-halitosis :When an obvious breath malodorcannot be perceived, but the patient is convincedthat he or she suffers from it .

Halitophobia : If the patient still believes that thereis bad breath after treatment of genuine halitosis ordiagnosis of pseudo halitosis .

ETIOLOGY In the vast majority, breath malodor originates

from the oral cavity. Gingivitis, periodontitis, andespecially tongue coating are the predominantcausative factors .

In general, one can identify two pathways for bad breath.

1- The first one involves an increase of certain

metabolites in the blood circulation (e.g., due to asystemic disease), which will escape via the alveoli of thelungs during breathing (blood-gas exchange).

2-The second pathway involves an increase of either the

bacterial load or the amount of substrates for thesebacteria at one of the lining surfaces of the oropharyngealcavity, the respiratory tract, or the esophagus. All types ofinfections, ulcerations, or tumors at one of the previouslymentioned areas can thus lead to bad breath.

Bacteria involved in Halitosis Porphyromonas gingivalis,

Prevotella intermedia/nigrescens,

Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans),

Campylobacter rectus,

Fusobacterium nucleatum,

Peptostreptococcus micros,

Tannerella forsythia, Eubacterium spp,, and spirochetes.

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a-Intraoral Causes1-Tongue and Tongue Coating

The dorsal tongue mucosa, with an area of 25 cm2,shows a very irregular surface topography . Theposterior part exhibits a number of ovalcryptolymphatic units, which roughen the surfaceof this area. The anterior part is even rougherbecause of the high number of papillae .

The accumulation of food remnants intermingledwith exfoliated cells and bacteria causes a coatingon the tongue dorsum. The latter cannot be easilyremoved because of the retention offered by theirregular surface of the tongue dorsum .

High correlations have been reported betweentongue coating and odor formation .

Different clinical pictures of heavily coated tongues.

2-Periodontal Infections

Several studies have shown a relationship betweenperiodontitis and oral malodor. However, not allpatients with gingivitis and/or periodontitis complainabout bad breath, and there is some disagreement inthe literature as to what extent oral malodor andperiodontal disease are related.

Bacteria associated with gingivitis and periodontitissuch as ANAG or ANAS in are indeed able to produceVSCs (A main cause of malodor) .

VSC levels in the mouth correlate positively with thedepth of periodontal pockets (the deeper the pocket,the more bacteria, particularly anaerobic species) andthat the amount of VSCs in breath increases with thenumber, depth, and bleeding tendency of theperiodontal pockets. VSCs aggravate the periodontitisprocess by increasing the permeability of the pocketand mucosal epithelium and therefore exposing theunderlying connective tissues of the periodontium tobacterial metabolites.

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Some studies, however, have shown that when thepresence of tongue coating is taken into account, thecorrelation between periodontitis and oral malodor ismuch lower, indicating that tongue coating remains akey factor for halitosis. The prevalence of tongue coatingis six times higher in patients with periodontitis, and thesame bacterial species associated with periodontaldisease can also be found in large numbers on thedorsum of the tongue .

3-pericoronitis Other relevant malodorous pathologic manifestations of

the periodontium are pericoronitis (the soft tissue “cap”being retentive for microorganisms and debris), majorrecurrent oral ulcerations, herpetic gingivitis, andnecrotizing gingivitis/periodontitis. Microbiologicobservations indicate that ulcers infected withgramnegative anaerobes (i.e., Prevotella andPorphyromonas species) are significantly moremalodorous than noninfected ulcers

4-Dental Pathologies deep carious lesions with food impaction and

putrefaction, extraction

wounds filled with a blood clot, and purulent dischargeleading to important putrefaction.

Interdental food impaction in large interdental areas

crowding of teeth favor food entrapment andaccumulation of debris.

Acrylic dentures, especially when kept continuously inthe mouth at night or not regularly cleaned, can alsoproduce a typical smell. The denture surface facing thegingiva is porous and retentive for bacteria, yeasts, anddebris, which are all factors that cause putrefaction

5-Dry Mouth

Saliva has an important cleaning function in the oralcavity. Patients with xerostomia often present with largeamounts of plaque on teeth and an extensive tonguecoating. The increased microbial load and the escape ofVSCs as gases when saliva is drying up explain thestrong breath malodor.

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b-Extraoral CausesSystemic diseases like

Diabetes Mellitus

Liver disease

Advanced kidney failure

Uremia

Ear, Nose, Throat problems

DIAGNOSIS OF MALODOR1-Medical History

The proper diagnostic approach to a malodor patientstarts with a thorough questioning about the medicalhistory. Asking about all the relevant pathologies forbreath malodor just discussed is not time-consuming; itmay save time and expenses to achieve a properdifferential diagnosis. As often repeated, “listen to thepatient and the patient will tell you the diagnosis.”

2-Self-Examination

Smelling a metallic or nonodorous plastic spoon afterscraping the back of the tongue.

Smelling a toothpick after introducing it in aninterdental area.

Smelling saliva spit in a small cup or spoon (especiallywhen allowed to dry for a few seconds so thatputrefaction odors can escape from the liquid).

Licking the wrist and allowing it to dry (reflects thesalivacontribution to malodor).

3-Oropharyngeal Examination.

The oropharyngeal examination includes inspectionof deep carious lesions, interdental food impaction,wounds, bleeding of the gums, periodontal pockets,tongue coating, dry mouth, and the tonsils and pharynx(for tonsillitis and pharyngitis).

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Tests used for diagnosis1- Organoleptic Rating

Even though devices are available, the organoleptic assessmentby a judge is still the “gold standard” in the examination ofbreath malodor. It is the easiest and most often used methodbecause it gives a reflection of the everyday situation whenhalitosis is noticed. Moreover, the human nose can smell 10,000different odors.39 In an organoleptic evaluation, a trained andpreferably calibrated “judge” sniffs the expired air and assesseswhether it is unpleasant by using an intensity rating, normallyfrom 0 to 5, as proposed by It is thus solely based on theolfactory organs of the clinician:

0 = no odor present, 1 = barely noticeable odor, 2 = slight but clearly noticeable odor, 3 = moderate odor, 4 = strong offensive odor, and 5 = extremely foul odor.

2-Portable Volatile Sulfur Monitor

The portable volatile sulfur monitor (Halimeter,Interscan, Chatsworth, CA) is an electronic device thatanalyzes the concentration of hydrogen sulfide andmethyl mercaptan but without discriminating themThe mouth air is aspirated by inserting a drinking strawfixed on the flexible tube of the instrument. The strawis kept about 2 cm behind the lips, without touchingany surface, while the subject keeps the mouth slightlyopen and breathes through the nose. The sulfur meteruses a voltametric sensor that generates a signal whenexposed to sulfur-containing gases.

Portable sulfide monitor (Halimeter)

3-Gas Chromatography

A gas chromatography device can analyze air, saliva, orcrevicular fluid About compounds have been isolatedfrom the headspace of saliva and tongue coating, fromketones to alkanes and sulfur-containing compounds tophenyl compounds. In the expired air of a person,

approximately 150 compounds can be found.

The most important advantage of the technique(together with mass spectrometry) is that it can detectvirtually any compound when using adequate materialsand conditions. Moreover, it has a very high sensitivityand specificity .

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Gas chromatography machinery, including thermal desorber (TD) to release molecules trapped in special collectors); gas chromatograph(GC) for separation of molecules; and mass spectrometer (MS) for identificationof molecules.

TREATMENT OF ORAL MALODOR

1- Mechanical reduction of intraoral nutrients (substrates)

and microorganisms

2- Chemical reduction of oral microbial load

Rendering malodorous gases nonvolatile

Masking the malodor

Treatment should be centered on reducing the bacterialload/ micronutrients by effective mechanical oral hygieneprocedures, including tongue scraping. Periodontal diseaseshould be treated and controlled

Mechanical Reduction of Intraoral Nutrients and Microorganisms

Cleaning of the tongue can be carried out with a normaltoothbrush, but preferably with a tongue scraper if acoating is established. Tongue cleaning using a tonguescraper reduced the halitosis levels with 75% after 1 week.This should be gentle cleaning to prevent soft tissuedamage. It is best to clean as far backward as possible; theposterior portion of the tongue has the most coating.100Tongue cleaning should be repeated until almost nocoating material can be removed .

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Interdental cleaning and toothbrushing are essentialmechanical means of dental plaque control. Bothremove residual food particles and organisms thatcause putrefaction. Clinical studies have shown thatexclusively brushing the teeth has no appreciableinfluence on the concentration of VSCs. In a short-term study, a combination of tooth and tonguebrushing or toothbrushing alone had a beneficialeffect on bad breath for up to 1 hour (73% and 30%reduction in VSCs, respectively).

Because periodontitis can cause chronic oral malodor,professional periodontal therapy is needed .

Chewing gum may control bad breath temporarilybecause it can stimulate salivary flow.

The salivary flow itself also has a mechanical cleaningcapability. Not surprisingly, therefore, subjects withextremely low salivary flow rate have higher VSCratings and tongue coating scores than those withnormal saliva production. It has been shown thatchewing of a gum without any active ingredient canreduce halitosis modestly.

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Chemical Reduction of Oral Microbial Load

Mouth rinsing has become a common practice inpatients with oral malodor. The active ingredients inoral rinses are usually antimicrobial agents such aschlorhexidine, cetylpyridinium chloride (CPC),essential oils, chlorine dioxide, hydrogen peroxide, andtriclosan. All these agents have only a temporaryreducing effect on the total number of microorganismsin the oral cavity .

1-Chlorhexidine

Chlorhexidine is considered the most effectiveantiplaque and antigingivitis agent. Its antibacterialaction can be explained by disruption of the bacterialcell membrane by the chlorhexidine molecules,increasing its permeability and resulting in cell lysis anddeath. Because of its strong antibacterial effects andsuperior substantivity in the oral cavity, chlorhexidinerinsing provides significant reduction in VSC levels andorganoleptic ratings.

2-Chlorine Dioxide.

Chlorine dioxide (ClO2) is a powerful oxidizingagent that can eliminate bad breath by oxidation ofhydrogen sulfide, methylmercaptan, and the aminoacids, methionine and cysteine. Studies demonstratedthat single use of a ClO2–containing oral rinse slightlyreduces mouth odor.

3-Two-Phase Oil-Water Rinse

Rosenberg et al designed a two-phase oil-water rinsecontaining CPC. The efficacy of oilwater- CPCformulations is thought to result from the adhesion of ahigh proportion of oral microorganisms to the oildroplets, which is further enhanced by the CPC. A twice-daily rinse with this product (before bedtime and in themorning) showed reductions in both VSC levels andorganoleptic ratings. These reductions were superior toListerine and significantly superior to a placebo .

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4-Triclosan

Triclosan, a broad-spectrum antibacterial agent, has beenfound to be effective against most oral bacteria and has agood compatibility with other compounds used for oralhome care. A pilot study demonstrated that anexperimental mouth rinse containing 0.15% triclosan and0.84% zinc produced a stronger and more prolongedreduction in mouth odor than a Listerine rinse. The anti-VSC effect of triclosan, however, seems stronglydependent on the solubilizing agents .

5-Aminefluoride/Stannous Fluoride

The association of aminefluoride with stannous fluoride(AmF/SnF2) resulted in encouraging reductions ofmorning breath odor, even when oral hygiene isinsufficient .

6- Hydrogen Peroxide

Suarez et al reported that rinsing with 3% hydrogenperoxide (H2O2) produced impressive reductions (±90%)in sulfur gases that persisted for 8 hours.

7- Oxidizing Lozenges

Greenstein et al reported that sucking

a lozenge with oxidizing properties reduces tongue dorsummalodor for 3 hours. This antimalodor effect may becaused by the activity of dehydroascorbic acid, which isgenerated by peroxide-mediated oxidation of ascorbatepresent in the lozenges.

Toothpastes Baking soda dentifrices have been shown to confer a

significant odor-reducing benefit for time periods upto 3 hours. The mechanisms by which baking sodaproduces its inhibition of oral malodor might berelated to its bactericidal effects and its transformationof VSCs to a nonvolatile state.

Gerlach et al compared the antimalodor efficacy ofthree different toothpastes and reported a slightlybetter outcome, especially

for an SnF2-containing paste (±50% reduction),whencompared towater (±35% reduction).

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Chewing Gum Chewing gum can be formulated with antibacterial

agents, such as fluoride or chlorhexidine, thushelping reduce oral malodor through bothmechanical and chemical Approaches

Waler compared different concentrations of zinc in achewing gum and found that a 2-mg Zn++ acetate–containing chewing gum that remained in the mouthfor 5 minutes resulted in an immediate reduction inthe VSC levels of up to 45%, but the long-term effectwas not mentioned.

Masking the Malodor Treatments with rinses, mouth sprays, and lozenges

containing volatiles with a pleasant odor have only a short-

term effect. Typical examples are the mint-containing

lozenges. Another pathway is to increase the solubility of

malodorous compounds in the saliva by increasing the

secretion of saliva; a larger volume allows the retention of

larger volumes of soluble VSCs. The latter can also be

achieved by ensuring a proper liquid intake or by using a

chewing gum; chewing triggers the periodontalparotid

reflex, at least when the lower (pre)molars are still present .

SUMMARY Breath malodor has important socioeconomic

consequences and can reveal important diseases .

A proper diagnosis and determination of the etiology

allow initiation of the proper etiologic treatment .

Although tongue coating and (less frequently)

periodontitis and gingivitis are by far the most

common causes of malodor, a clinician cannot take the

risk of overlooking other, more challenging diseases .