A structural equation model relating objective and subjective masticatory function and oral health-related quality of life in patients with removable partial dentures.

The aim of this study was to investigate the relationships between objective masticatory function with respect to masticatory performance and food mixing ability, patients' perception of chewing ability and oral health-related quality of life (OHRQoL). Partially dentate patients with removable partial dentures (n = 131, mean age 67·1 year) participated in the study. Four tests were performed to evaluate objective and subjective masticatory function and OHRQoL. Masticatory performance and food mixing ability were assessed using peanuts or a two-coloured wax cube as test items. Patients' perception of chewing ability was rated using a food intake questionnaire. OHRQoL was measured using the Japanese version of the oral health impact profile. A structural equation model was constructed based on hypothesis in which objective masticatory function would be related to OHRQoL via perceived chewing ability as a mediator. Structural equation modelling analysis found a statistically significant medium effect of perceived chewing ability on OHRQoL and statistically significant medium or small effects of masticatory performance on perceived chewing ability and OHRQoL (P < 0·05); however, the effect of food mixing ability on perceived chewing ability or OHRQoL was not statistically significant (P > 0·05). A fit index indicated that the model fitted well to the data (Goodness-of-fit index = 0·99). These results suggest that perceived chewing ability is a critical factor for OHRQoL and that masticatory performance rather than food mixing ability is important for perceived chewing ability and OHRQoL in patients with removable partial dentures.