Table 1: Ultrasound velocity and elastic property of the condyle (mean SD, ).

Ultrasound velocity

Elastic coefficients

Technical constants (GPa)

( m/s)

(GPa)

Young’s modulus

Shear modulus

Poisson’s ratio

: ultrasound velocities that were measured directly by ultrasonic method; , , , , , were longitudinal wave speed measured with the generation and sensing transducer in line, and , , were the transverse wave speed measured with the generation and sensing transducer at a right angle. : elastic coefficients that were calculated from . (Young’s modulus), (Shear modulus), and (Poisson’s ratio) were calculated from and would be further applied into the finite element analysis for material definition of the condyle. For subscript numbers of , , , and . 1 was in the antero-posterior direction, 2 was in the vertical direction, and 3 was in the mesio-lateral direction, while the subscript numbers of did not the indicate directions, which were just the calculation results from and further for calculating the technical constants.