Which lifestyle factor is listed as a cause of reduced salivary flow due to decreased masticatory activity?

• A. Smoking
• B. Liquid diet or soft food
• C. Mouth breathing
• D. Aging

Answer: (B)

Saliva production is closely tied to chewing. The act of mastication provides mechanical stimulation and, along with taste cues, activates the salivary glands through the parasympathetic nervous system, increasing salivary flow to help lubricate and digest food. When your diet consists of liquids or soft foods, you chew far less, so there’s less neural stimulation of the glands. The result is a drop in salivary flow.

Other factors can influence dryness in different ways. For example, smoking can cause a sensation of dry mouth or reduce saliva due to irritants and dehydration, but it isn’t about decreasing masticatory activity. Mouth breathing dries the oral surfaces through evaporation, not through reduced chewing. Aging can also reduce saliva production, but that’s more about glandular changes than a reduction in chewing.