The assessment of oral dryness by photographic appearance of the tongue.

Background: Oral dryness or hyposalivation is a major clinical problem. Several chairside tests or visual inspections of the oral cavity have been proposed for the assessment.
Objective: To identify whether photographs of the tongue could be used to identify oral dryness.
Material and Methods: Twenty-five dentists and 25 individuals with another academic background were recruited. They assessed the severity of the oral dryness of 50 patients, based on an intraoral picture of each patient. The oral dryness was quantified with a five-point Likert scale and the scores were subsequently compared with the salivary flow rate and the level of xerostomia of these patients.
Results: No relation was found between the unstimulated salivary flow rate of a patient and the average oral dryness score, determined by dentists (p = 0.260) as well as non-dentists (p = 0.806). Also no relation was found between the self-reported xerostomia level of the patient and the average dryness score assessed by the dentists (p = 0.171) or non-dentists (p = 0.477).
Conclusion: It does not seem possible to diagnose oral dryness by mere visual inspection of photographed tongues. Thus, for correct diagnosis of oral dryness further clinical investigation of the oral cavity and collection of saliva is indicated.