title: Changes in human jaw muscles with age and dental state.
abstract: The effects of ageing and dental state on the cross-sectional area and density of two jaw muscles, the masseter and medial pterygoid, were investigated using computed tomography. The study involved 84 male and 70 female subjects between the ages of 20 and 90 years. The cross-sectional area of both muscles showed a significant reduction with age; values for female subjects being found in the lower range of the distribution. When consideration was given to the presence or absence of a natural dentition, the cross-sectional area of both muscles in edentulous subjects showed a greater decrease throughout the age range studied. There was a significant decrease in the density of the muscles with increasing age. Previously, this has been interpreted to indicate a progressive increase in fat and fibrous tissue. Subject gender and the absence of teeth appeared to have little effect on this parameter. Changes in the cross-sectional area and density of these muscles would appear to be consistent with a general age related change of muscle tissue in the body as a whole and may specifically indicate a reduction in the masticatory forces which can be or are being utilised by ageing patients, many of whom have no remaining natural dentition.
authors.affiliation: Department of Dental Prosthetics and Gerontology, The Dental School, University of Dundee, UK.
authors.forename: J P
authors.initials: JP
authors.lastname: Newton
authors.forename: R
authors.initials: R
authors.lastname: Yemm
authors.forename: R W
authors.initials: RW
authors.lastname: Abel
authors.forename: S
authors.initials: S
authors.lastname: Menhinick
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001732:Bite Force; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007575:Jaw, Edentulous / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D008406:Masseter Muscle / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000473:pathology; D008410:Masticatory Muscles / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000473:pathology*; D008875:Middle Aged; D011626:Pterygoid Muscles / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000473:pathology; D012044:Regression Analysis; D012737:Sex Factors; D014057:Tomography, X-Ray Computed