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Pathology · single question

All of the following are recognized contributing factors to halitosis (bad breath) EXCEPT one. Which is the EXCEPTION?

  1. Blood glucose levels
  2. Dry mouth (xerostomia)
  3. Food debris and plaque on the tongue dorsum
  4. Volatile sulfur compounds (VSC) from anaerobic bacteria
Show answer and explanation

Correct answer: A. Blood glucose levels

  • A. CORRECT. Blood glucose levels do NOT directly cause halitosis in the sense of contributing to volatile sulfur compound production by oral bacteria. While uncontrolled diabetics may have a fruity/acetone breath from ketoacidosis (ketones, not VSCs), normal variations in blood glucose within the physiological range do not contribute to typical oral halitosis.
  • B. Xerostomia reduces salivary flow, decreasing the mechanical cleansing of the oral cavity and reducing antibacterial protection, allowing VSC-producing bacteria to flourish.
  • C. Tongue dorsum coating with food debris and plaque is the #1 source of intraoral halitosis — the posterior dorsal tongue is the primary site of VSC production.
  • D. Volatile sulfur compounds (H2S, methyl mercaptan) are the primary chemical cause of halitosis — produced by anaerobic gram-negative bacteria metabolizing sulfur-containing amino acids.

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