The oral biology of bad breath

1. The oral biology of bad breath DENT 5301 Introduction to Oral Biology Dr. Joel Rudney

2. 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

3. What smells? • Products of bacterial activity • Volatile sulfur compounds (VSC) • Hydrogen sulfide (H2S) - rotten eggs • Methyl mercaptan (CH3SH) - natural gas • Major components of mouth odor in most persons • Cadaverine - diamino acid - spoiled meat • Also important • Produced independently of VSC • Organic acids - goaty smells • Acetic, propionic, butyric, isovaleric

4. 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

5. 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

6. 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

7. 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"

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

9. 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 halitosis • Many novel species (n = 6) • Digest nasal discharges, food debris, saliva components, sloughed cells • Produce VSC, cadaverine • BANA hydrolysis test (Perioscan®) used for detection • Periodontal pathogens

10. Systemic smells • About 90% of halitosis originates in the mouth • The other 10% • Systemic disease • Diabetes - ketoacidosis - acetone smell • Cirrhosis, liver failure - "mousy", "musty" smells • Renal failure - fishy smell • Leukemia - "decaying blood" smell • Respiratory system • Exhalation of volatile food compounds • Volatile medications - DMSO, amyl nitrate • Nasal/sinus/lung infections • Tonsils and tonsiloliths (may not contribute to mouth odor) • Treated by laser cryptolysis • Carcinoma

11. 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 metabolism • Very high VSC levels (gut bacteria)

12. 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

13. “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 heterozygotes • May be more common than once thought • Saliva TMA detectable by patient, but not others

14. 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

15. 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)

16. 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 scrapers • Many designs on the market • The gag reflex is a barrier to compliance

17. Tongue scraping http://www.yatan-ayur.com.au/images/tonguecleaning2.jpg One of many designs - no endorsement implied

18. 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 udders • FDA approved for 2ndary food use (disinfecting chickens) • Appears to be safe at concentrations in breath products • Only two published studies - short-term , small Ns • Zinc reacts with VSC • Safe when not used in excess • More published evidence - small Ns • Reduces VSC levels short-term

19. 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 use • More effective than Listerine (essential oils) - both worked • Currently available in Israel and Great Britain • Toothpaste with substantive triclosan copolymers - short term • Mixtures including low dose chlorhexidine - Halita

20. 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-cariogenic • Lots 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 flora • Step 2: Replace tongue flora with K12 • Limited data - 2 wks., N = 13, only 3 controls, not yet published

21. 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)

22. Why so few studies? • No product currently has the ADA seal for halitosis • Some do have the ADA seal for other properties • Plaque 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 zinc • S. salivarius K12 • Manufacturers lack incentives to do the studies