The aim of this study was to determine the shear stress of the human p
ostmortem temporomandibular joint (TMJ) disc. Correlation of shear str
ess with age or with the region of the disc was determined. Nine discs
were removed unilaterally from postmortem humans, ages 36 to 76 years
. Discs were sectioned into lateral (eight), central (eight), and medi
al (eight) specimens. Each specimen was attached by cyanoacrylate adhe
sive to a servohydraulic test system apparatus within 48 hours of retr
ieval. Shear properties were measured under quasistatic conditions wit
h a linear increase of displacement until the specimen failed to maint
ain maximum resistance to the applied force. The shear,noduli were ana
lyzed by means of the Wilcoxon's signed ranks test. The results showed
that values of shear moduli on peripheral portions (lateral and media
l) there significantly higher than on central portions (P = 0.0013). T
he correlation between the shear moduli of TMJ discs and age showed a
regression slope for shear moduli of-0.326 + 0.031 x age (r = 0.769; P
< 0.01). Peripheral portions (lateral and medial) have a higher shear
moduli and ale stiffer than the central portions of !discs and shear
moduli ol stiffness of TMJ discs increase with age.