A Cross-Sectional Study of Age-Related Changes in Oral Function in Healthy Japanese Individuals

Abstract

Background: Oral function deterioration is related to a variety of factors, including aging, decline in activities of daily living, malnutrition, and cognitive decline. This cross-sectional study examined the effects of aging on oral function in healthy individuals.

Methods: A retrospective study was conducted on 175 healthy, independent patients aged 40-89 years, without dementia and with ≥20 teeth, who visited a local dental clinic in Japan. Patients were compared with 92 university students aged 20-29 years. The seven criteria proposed by the Japanese Society of Gerodontology to diagnose "oral hypofunction" were observed and statistically analyzed.

Results: Compared with those in the control group, the degree of tongue coating was increased in the group aged over 80 years, occlusal force was decreased in the group aged 70-79 years, tongue motor function was decreased in the groups aged 60-69 years and older, and tongue pressure was decreased in the groups aged 70-79 years and older.

Conclusions: Healthy, independent individuals maintained several oral function criteria across aging, including oral mucosal wetness, occlusal force, lip motor function, masticatory function, and swallowing function. Tongue motor function and tongue pressure decreased with aging, indicating that these may be rehabilitation targets.

Keywords: aging; cross-sectional study; independent elderly; oral function.

Figure 1

Oral function criteria results. A–H: The box plots show the value of each investigated criteria for each group. The horizontal line in the boxes is the median; the bottom of the box is the first quartile (25%), the top of the box is the third quartile (75%), and both ends of the mustache are the maximum and minimum values. I: The percentage of the number of applicable items in the questionnaire for each age group is shown. Asterisk (*) indicates p-value < 0.05.