Factors related to dissociation between objective and subjective masticatory function in Japanese community-dwelling elderly adults

Clinicians' evaluations of older adults sometimes reveal inconsistencies between objective and subjective dental status. This study investigated which factors contribute both to good objective masticatory function (OMF) and the poor subjective masticatory function (SMF) that often becomes a clinical issue. Study participants included 635 elderly community-dwelling Japanese adults who underwent a comprehensive geriatric health examination in 2012. SMF was assessed with a question from the Kihon Checklist on eating difficulties (poor or good). OMF was assessed by a colour-changing gum (poor or good). Also investigated were age, sex, depressive symptoms, instrumental activities of daily living (I-ADLs), number of people who joined the participant at dinner, grip strength, usual walking speed, number of remaining teeth, number of functional teeth and their occlusal force. The group with good OMF and good SMF, defined as group 1, and the group with good OMF but poor SMF, group 2, were compared. Logistic regression analyses confirmed that the number of remaining and functional teeth participants had was statistically unrelated to differences between OMF and SMF. Instead, differences were related to stronger depressive symptoms (OR=1.67, CI=1.14-2.44), less ability to conduct I-ADL activities (OR=0.73, CI=0.59-0.91), slower usual walking speeds (OR=0.18, CI=0.06-0.58) and less occlusal force (OR=0.99, CI=0.99-1.00). Depressive symptoms, I-ADLs, and physical function are shown to be significantly related to divergence between objective and subjective masticatory function in elderly Japanese. This suggests that dissociations between objective and subjective dental evaluations of elderly adults indicate need for assessment of their mental and physical function.