Prevention of Halitosis and Cleansing of the Oral Cavity

Halitosis is bad-smelling breath. It can be caused due to improper brushing, tooth/gum disease or intestinal problems. (Mayo Clinic. Retrieved 28th Oct 2009) Our main concern is with the causes of halitosis in the oral cavity.

Poor oral hygiene when the teeth are not brushed properly cause food debris to accumulate in the sulcus of the gums, in the interproximal spaces between the teeth and in the fossa and grooves on the occlusal surface of the premolars and molars. Bacteria then adsorb onto and colonise the pellicle of the teeth, obtaining their nutrients from the retained food particles. Bacteria also colonise and obtain their nutrients from the food particles that are retained by the microvilli on the tongue. The breakdown of food particles by bacteria produces compounds, in particular methyl mercaptan and H2S contributing to much of the odor in halitosis. (Cole, A.S and Eastoe, J.E., 1998)

The byproduct lactic acid is produced when the bacteria such as Streptoccocus mutans and Lactobacilli breaks down the food particles. This initiates the process of caries leading to endodontic diseases. The decay of the pulp chamber of the tooth and subsequent abscess formation contributes to halitosis.

Plaque accumulation from the adsorption of bacteria onto the pellicle on the tooth can spread to below the gum line. Toxins produced by the plaque stimulates the chronic inflammation of the gums (activation of macrophages) thus leading to the breakdown of tissue and bone hence the deepening of the periodontal pocket. The accumulation of food particles and bacteria in the gingivial sulcus contributes to the formation of abscesses due to infection, contributing to halitosis as periodontic disease progresses. (Mayo Clinic. Retrieved 28th Oct 2009)

Saliva therefore helps to reduce halitosis as it loosens food particles, dead oral epithelial cells, and agglutinated bacteria, which contribute to the production of halitosis. [Refer to mechanical action of saliva for more details.] Increased salivary flow and water in the saliva dilutes and removes organic constituents of saliva producing methyl mercaptan and H2S, helping reduce halitosis. The agglutinated bacteria, food debris and oral epithelial cells are loosened by saliva via mechanical action and subsequently swallowed. (University of Newcastle Dental School, retrieved Oct 11, 2009)


  1. University of Newcastle Dental School. Bite-Sized Tutorials: Why Plaque Forms at Specific Sites. Retrieved October 11, 2009 from
  2. Cole, A.S. & Eastoe, J.E. (1998). Biochemistry and Oral Biology 2nd ed.). J. Wright.
  3. Roth, G.I., & Calmes, R. (1981). Oral Biology. St. Louis: C.V. Mosby Company.
  4. Mayo Clinic. Bad breath: Causes. Retrieved Oct 28, 2009 from
  5. Selection and use of lactic acid bacteria for reducing dental caries and bacteria causing dental caries. Retrieved October 31, 2009 from

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