Sialometry

Sialometry is a set of procedures used to quantify salivary production to assess salivary gland function and diagnose disorders such as xerostomia or Sjögren's syndrome. It typically evaluates unstimulated (basal) saliva and stimulated saliva, often using whole saliva but can include gland-specific measurements via duct cannulation.

Unstimulated saliva collection involves passive drool or spit into a preweighed container over a fixed interval (commonly 5–15 minutes). Stimulated saliva is collected after applying a sialogogue (such as citric acid or lemon juice) or mechanical stimulation (chewing) for a defined period. In some cases, gland-specific sialometry targets saliva from the parotid or submandibular glands by collecting from the duct openings.

Saliva volume is measured and the flow rate calculated in milliliters per minute (mL/min). Normal ranges vary, but commonly reported values are approximately 0.3–0.5 mL/min for unstimulated saliva and 1–2 mL/min or higher for stimulated saliva. Values below these ranges are interpreted as hyposalivation. Results must be considered with hydration, circadian variation, medications, and technique variability.

Sialometry is used to evaluate salivary gland function in patients with dry mouth, Sjögren's syndrome, radiation-induced xerostomia, diabetes, or after head and neck therapy, and to monitor interventions. Limitations include marked intra- and inter-individual variability, lack of universal standardization, and the influence of nutritional status, medications, and timing.