title: Topographic distribution of bacteria associated with oral malodour on the tongue.
abstract: OBJECTIVE
  To investigate the topographic distribution of bacterial types and loads associated with mid-morning oral malodour on the tongue surface.
  
  
  METHODS
  Fifty subjects with good oral health and at least 20 natural uncrowned teeth were included. Samples were taken with sterile brushes from the dorsal anterior (DA), dorsal middle (DM), dorsal posterior (DP), dorsal posterior to the circumvallate papillae (DPCP), lateral posterior (LP) and ventral posterior (VP) tongue surfaces. Samples were cultured on appropriate media for anaerobic bacteria, aerobic bacteria, Gram-negative anaerobic bacteria, volatile sulphur compound (VSC)-producing bacteria and Streptococcus saliuarius. Malodour was assessed by trained judges on an intensity basis.
  
  
  RESULTS
  The counts of all bacterial groups were consistently highest at the DPCP surface. Mean VSC-producing bacterial counts (colony forming units/brush x10(5)) were 1.45, 5.67, 32.52, 88.94, 6.46 and 0.33 at DA, DM, DP, DPCP, LP and VP surfaces, respectively. Anaerobic, Gram-negative and VSC counts at DPCP surfaces increased with malodour intensity, whereas aerobic and S. saliuarius counts decreased; however these differences were not statistically significant.
  
  
  CONCLUSIONS
  It is concluded that the DPCP area consistently carries the highest load of bacteria capable of contributing to oral malodour. The study demonstrates that tongue surfaces not accessible to routine oral hygiene procedures can significantly contribute to oral malodour.
authors.affiliation: Institute of Dentistry, Barts & The London School of Medicine and Dentistry, Queen Mary University of London, London, UK. R.P.Allaker@qmul.ac.uk
authors.forename: Robert P
authors.initials: RP
authors.lastname: Allaker
authors.forename: Richard D
authors.initials: RD
authors.lastname: Waite
authors.forename: Jenneth
authors.initials: J
authors.lastname: Hickling
authors.forename: Mairead
authors.initials: M
authors.lastname: North
authors.forename: Rod
authors.initials: R
authors.lastname: McNab
authors.forename: Marylynn P
authors.initials: MP
authors.lastname: Bosma
authors.forename: Francis J
authors.initials: FJ
authors.lastname: Hughes
mesh_terms: D000293:Adolescent; D000328:Adult; D001419:Bacteria / Q000302:isolation & purification; D015169:Colony Count, Microbial / Q000379:methods; D005260:Female; D005881:Gingiva / Q000382:microbiology*; D006209:Halitosis / Q000382:microbiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009910:Oral Hygiene / Q000379:methods; D013440:Sulfides / Q000378:metabolism; D014059:Tongue / Q000382:microbiology*
chemical_list: D013440:Sulfides