Which of the following is NOT one of the three components of dental caries etiology?

• A. Tooth
• B. Substrate
• C. Flora
• D. Saliva

Answer: (D)

Caries etiology hinges on three interacting factors: a susceptible tooth surface (host), a substrate of fermentable carbohydrates (dietary substrate), and the bacteria in dental plaque that metabolize those carbohydrates to acids (flora). Saliva, while crucial for prevention, acts as a protective influence rather than one of the etiologic components. It helps by buffering acids, supplying minerals for remineralization, washing away sugars and plaque, and helping control bacterial activity. Because of these protective roles, saliva isn’t counted among the three factors that initiate caries. So, the option that is NOT one of the three components is saliva. The other two components fit the trio: the tooth as the host, the substrate as the carbohydrate source, and the flora as the acid-producing bacteria.