Masticatory performance in older subjects with varying degrees of tooth loss.
OBJECTIVE
The purpose of this study was to establish the factors influencing the masticatory performance of older subjects with varying degrees of tooth loss and associated numbers of posterior occlusal contacts.


METHODS
The subjects consisted of 1274 independently living people aged 60 years and over. Individuals with partially or fully edentulous arches without a denture replacement or those having any symptoms related to an oral problem were excluded from the study participants. Masticatory performance, maximal occlusal force and stimulated whole saliva were measured. Subjects were grouped into three categories by posterior occlusal contact, according to the Eichner Index. Group A had contacts in four support zones; group B had one to three zones of contact or contact in the anterior region only; and group C had no support zones at all, although a few teeth could still remain.


RESULTS
The masticatory performance in groups B and C was found to be 81% and 50% of that of group A, respectively. The multiple linear regression analysis showed that in all the groups, occlusal force was significantly associated with masticatory performance. In groups A and B, the number of residual teeth was significantly associated with masticatory performance, whereas in group C, it had no significant relationship with masticatory performance. Salivary flow rate had a significant correlation with masticatory performance only in group C.


CONCLUSIONS
Declines in occlusal contact, occlusal force and salivary flow appear to be associated with reduction of masticatory performance in older adults. However, the crucial factors for masticatory performance varied, depending on the phase of occlusal collapse.
Department of Prosthodontics, Gerodontology and Oral Rehabilitation, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka 565-0871, Japan. ikebe@dent.osaka-u.ac.jp
Kazunori
K
Ikebe
Ken-ichi
K
Matsuda
Ryosuke
R
Kagawa
Kaori
K
Enoki
Tadashi
T
Okada
Minoru
M
Yoshida
Yoshinobu
Y
Maeda
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D001641:Bicuspid / Q000502:physiology; D001732:Bite Force; D003430:Cross-Sectional Studies; D003766:Dental Occlusion; D005260:Female; D006801:Humans; D057187:Independent Living; D016014:Linear Models; D008297:Male; D008409:Mastication; D008875:Middle Aged; D008963:Molar / Q000502:physiology; D012463:Saliva / Q000378:metabolism; D012636:Secretory Rate; D016388:Tooth Loss / Q000145:classification / Q000503:physiopathology*