Association of masticatory performance and oral conditions of older adults in Hong Kong

Abstract

This thesis consists of two systematic reviews and two original studies related to masticatory performance.

The first systematic review aimed to evaluate the Patient-Reported Outcome Measures (PROMs) for masticatory function in adults. Five electronic databases were searched for studies reporting development or validation of PROMs for masticatory function in adults. Methodological quality of the included studies and psychometric properties of the PROMs were evaluated. Twenty-three studies investigating 19 PROMs were included. Four types of PROMs were identified: questions using food items, questions on chewing problems, questions using both food items and chewing problems, and a global question. Methodological qualities and psychometric properties were diverse. Currently, there is no PROM for masticatory function in adults with high-level evidence for all psychometric properties.

The second systematic review aimed to give an overview on the associations between oral condition factors and masticatory performance in adults. Three electronic databases were searched for cross-sectional studies on oral conditions and masticatory performance in adults. Methodological quality of the included studies was evaluated. Data on the associations between oral condition factors and masticatory performance were extracted. 88 studies were included. Number of natural/remaining teeth and functional tooth pairs, perioral muscle status, oral moisture status, dental prosthetic status and periodontal status are the main oral condition factors influencing masticatory performance. Results of the meta-analyses showed that with a very low or low quality of evidence, the positive association with the number of natural/ remaining teeth was the strongest, followed by the number of functional tooth pairs, maximum tongue force/pressure, while the association with oral moisture status was the weakest.

A questionnaire-based measurement tool for assessing perceived chewing ability was developed and validated in the first study. The study was a cross-sectional study on 211 older adults recruited from a dental hospital, three community centers and an elderly home. Participants were asked to indicate their ability to chew on several selected food items. Masticatory performance was objectively assessed by asking the participant to chew a color-changeable gum for 90 seconds. Maximum bite force was also measured by an electronic detector. The reliability and validity of the developed questionnaire were assessed. It reveals that the developed unidimensional chewing function questionnaire is valid and reliable for assessing self-rated chewing ability of Chinese older adults.

The second study investigated the associations between oral conditions and masticatory performance and other related outcomes. The study was a cross-sectional study on 652 independently living older adults recruited from three general outpatient clinics and six community centers. Status of teeth, occluding pairs, oral moisture, objective masticatory performance, maximum bite force, and perceived chewing ability were assessed. It reveals that natural occluding tooth pairs and mobility of teeth affects masticatory performance, perceived chewing ability and maximum bite force. Besides, prosthetic rehabilitation by fixed prostheses and removable dentures has small to medium effects on masticatory performance and perceived chewing ability. Decayed teeth have a small effect on posterior maximum bite force, but are not significant on masticatory performance, perceived chewing ability, and anterior maximum bite force.