Survey of oral hypofunction in older outpatients at a dental hospital

Background Oral hypofunction is defined as the reversible stage preceding oral dysfunction. However, its assessment and management need further examination and consideration. Objective The present study aimed to examine the current state of oral hypofunction among outpatients at the university hospital. Methods New outpatients underwent medical interviews and detailed assessment of oral hypofunction at their initial visit to our dental department. Oral hypofunction was diagnosed if results of three of the following seven assessment items were below cutoff values: poor oral hygiene, oral dryness, reduced occlusal force, decreased tongue-lip motor function, decreased tongue pressure, decreased masticatory function, and deterioration of swallowing function. The relationships between factors used to diagnose oral hypofunction as well as the distributions of assessment values were clarified. Results Seventy-five of 209 patients (35.9%) were finally diagnosed with oral hypofunction. Diagnosis of oral hypofunction was significantly related to patient age, Eichner index, a chief complaint of dental or periodontal disease or ill-fitting dentures, and a history of neurodegenerative disease. The lowest quintile values for poor oral hygiene, oral dryness, and decreased masticatory performance were all above current cutoff values. Reduced occlusal force contributed strongly to the diagnosis of oral hypofunction. Conclusion Oral hypofunction in dental outpatients at a university hospital was associated with patient age, medical history, and chief complaint at presentation. Diagnosis of oral hypofunction can be closely related to reduced occlusal force. The validity of cutoff values for assessments of oral hypofunction needs further consideration.