The oral biology of bad breath

DENT 5301Introduction to Oral BiologyDr. Joel Rudney

Why is it important? Mouth odor can be a sign of undiagnosed disease

Mouth odor has negative connotations in many cultures Affects patient's self-image Affects others’ attitudes towards patient

Bad breath is big business Mouthwashes, mints, drops, gums, toothpastes Commercials reinforce existing attitudes

Dentists are consulted for advice, treatment Active marketing of "breath treatment clinic" franchises

What smells?

Products of bacterial activity Volatile sulfur compounds (VSC)

Hydrogen sulfide (H2S) - rotten eggsMethyl mercaptan (CH3SH) - natural gasMajor components of mouth odor in most persons

Cadaverine - diamino acid - spoiled meatAlso importantProduced independently of VSC

Organic acids - goaty smellsAcetic, propionic, butyric, isovaleric

What smells too?

Products of metabolic activity Volatile food components

Garlic, onions, etc.Broccoli, cauliflower (sulfur-rich)

Ketones (acetone)Low carb diets

Trimethylamine (fishy odor) Tobacco smoke Beer, wine, and liquor

How much does it smell?

Instruments for odor detection Gas chromatography of breath samples

Most informative Extremely sensitive and precise Expensive and cumbersome Limited to research centers

Portable sulfide meter (the Halimeter®) Can be used in a dental office Detects only VSC Must be calibrated regularly to maintain accuracy

Who smells it? Organoleptic ratings - the odor judge

Trained noses partly agree with sulfide meters May be more relevant clinically Requires extensive training, periodic calibration Mainly for research, specialized clinics

The jury of one's peers Your spouse or your best friends Your dentist (or your patient) Relevant to the social consequences of mouth odor

Self-incrimination - least reliable Many cannot detect odors apparent to others Some perceive odors no one else can detect

Where does it smell? Posterior tongue

Odor scores associated with degree of tongue coating Tongue anatomy may increase risk (deep fissures) May be primary source of odor in younger patients Worse with dry mouth, after sleeping

Periodontal pockets in periodontal disease Odor scores associated with disease/severity VSC can be measured in fluid from deep pockets Mouth odor/VSC proposed as early sign of periodontitis Not all periodontal patients have mouth odor

Other oral lesions (e.g. abcesses, impactions) Oral candidiasis - "Sweet, fruity odor"

Tongue coating

http://www.dent.ohio-state.edu/oralpath2/Tongue/25_2.jpg

Which bacteria are smelly?

Tongue bacteria Streptococcus salivarius - a sign of “health”?

May be dominant in persons w/o halitosis (n = 5) Gram-negative, proteolytic anaerobes

May predispose towards halitosisMany novel species (n = 6)Digest nasal discharges, food debris, saliva components, sloughed cellsProduce VSC, cadaverineBANA hydrolysis test (Perioscan®) used for

detection Periodontal pathogens

Systemic smells

About 90% of halitosis originates in the mouth The other 10%

Systemic diseaseDiabetes - ketoacidosis - acetone smellCirrhosis, liver failure - "mousy", "musty" smellsRenal failure - fishy smellLeukemia - "decaying blood" smell

Respiratory systemExhalation of volatile food compoundsVolatile medications - DMSO, amyl nitrateNasal/sinus/lung infectionsTonsils and tonsiloliths (may not contribute to mouth odor)

• Treated by laser cryptolysisCarcinoma

Other systemic smells

Gastrointestinal system (considered rare) Reflux Carcinoma Helicobacter pylori infection (gastric ulcers)

Genetic disorders (enzyme deficiencies) Trimethylaminuria (fishy odor) - autosomal recessive Cystinuria, cystathionuria heterozygotes

Recessive defects in cysteine metabolismVery high VSC levels (gut bacteria)

Iatrogenic/idiopathic smells

Frustrating to diagnose and treat - expensive Iatrogenic odors

Gauze pad left behind after cleft palate surgery Foreign objects

Inserted up the nose Young children and developmentally disabled If undetected, may lead to odor in adults

Idiopathic odors Detectable by others, no apparent oral or non-oral

cause Cause presumed rare, not yet defined

“Psychosomatic” smells

Detectable only by patient - no apparent cause Patients often refuse to accept objective findings Associated with anxiety or depression Can be confused with genetic disorders

Patients may show abnormalities by gas chromatography

Trimethylaminuria heterozygotesMay be more common than once thoughtSaliva TMA detectable by patient, but not others

Diagnosing smells

History Onset, duration? Constant or intermittent, morning, how long after meals? Self-report, or reported by others? Dietary factors, smoking and alcohol use? Systemic disease and medication Neurological problems - taste and smell function? Currently under stress? Comprehensive oral examination

Diagnosis by smelling No commercial mouth rinses for 1 day previous No eating, drinking, brushing, gum, mints, rinses for 2 h Avoid perfumes or scented products (patient; dentist) 2 min rest with lips closed - exhale through nostrils 2 min rest as before - close nostrils - exhale through lips 2 min rest as before - exhale with lips and nostrils open Sample posterior tongue with plastic spoon Compare odor strength for each condition Interpretation

Strongest odor with lips closed - suggests nose, sinuses Strongest odor with nostrils closed - oral or gastric source Tongue sample to confirm oral origin Odor equally strong from nose or mouth - systemic No discernible odor - verify with others (spouse, friend)

Treating smells - the basics

Non-oral etiologies - appropriate referral Oral etiologies

Treat all existing conditions Attempt to improve hygiene, flossing Encourage posterior tongue hygiene

Commercial tongue scrapersMany designs on the marketThe gag reflex is a barrier to compliance

Tongue scraping

http://www.yatan-ayur.com.au/images/tonguecleaning2.jpg

One of many designs - no endorsement implied

Treating smells - short-term

Masking fragrances Mouth rinses, drops, gums, mints, etc.

Chemicals that interact with VSC Sold online - by dentists offering halitosis clinics Oxidizing agents - products based on chlorine dioxide

Disinfectant - water treatment, pulp mills, cow uddersFDA approved for 2ndary food use (disinfecting chickens)Appears to be safe at concentrations in breath productsOnly two published studies - short-term , small Ns

Zinc reacts with VSCSafe when not used in excessMore published evidence - small NsReduces VSC levels short-term

Treating smells - long-term Antibacterial products

Should reduce bacterial odors, depending on efficacy Very few clinical studies document effects on odor long term

Chlorhexidine is considered the gold standard High substantivity - remains on oral tissues for a long time Only by Rx in USA, problems with taste and staining

Others with published evidence for odor reduction Two-phase oil-water mouthrinse (cetylpyridinium chloride)

Sulfides lower after 6 weeks of useMore effective than Listerine (essential oils) - both workedCurrently available in Israel and Great Britain

Toothpaste with substantive triclosan copolymers - short term Mixtures including low dose chlorhexidine - Halita

Treating smells - probiotics?

The probiotic concept Replace “bad” bacteria with “good” bacteria Lots of ongoing research - NIH funded FDA approves human trial of probiotic S. mutans

Genetically engineered to be non-cariogenicLots of safeguards required

Probiotic treatment of bad breath in New Zealand and Australia S. salivarius strain K12

Indigenous strain that produces antibacterial peptides (BLIS)Patented, marketed as a dietary supplement (now in USA)Step 1: Use chlorhexidine to knock down tongue floraStep 2: Replace tongue flora with K12

Limited data - 2 wks., N = 13, only 3 controls, not yet published

ADA halitosis standards

Must be met to get ADA seal for any bad breath claims Applies to products that already have ADA seal for other claims

Two independent double-blind efficacy studies Minimum 3-week trial period Patients must have baseline organoleptic scores between 2-5

“Slight” to “Very Strong” Gas chromatograph preferred to measure VSC

Sulfide monitor OK if calibration data provided Multiple malodor measurements Parallel evaluation of hard/soft tissue effects, microbiology

Long term safety data (six month follow up)Must include patient-reported adverse effects (taste/staining)

Toxicity data (cytotoxic, mutagenic, carcinogenic effects)

Why so few studies? No product currently has the ADA seal for halitosis

Some do have the ADA seal for other propertiesPlaque control or caries prevention

Will the public make this distinction?Is there a marketing benefit to getting the halitosis seal?

FDA approval May be sought under less stringent standards for cosmetics Ingredients already approved as safe for human use

Chlorine dioxide products May fall under the much weaker rules for dietary supplements

Products containing zincS. salivarius K12

Manufacturers lack incentives to do the studies