Table 1.

Ultrasound velocity and elastic property of the condyle (mean ± SD, n = 6).

Ultrasound velocity		Elastic coefficients		Technical constants (GPa)
(×103 m/s)		(GPa)		Young's modulus		Shear modulus		Poisson's ratio
v11	1.73 ± 0.04	c11	4.19 ± 0.12	E1	3.05 ± 0.16	G12	0.88 ± 0.03	ν21	0.42 ± 0.03
v22	1.79 ± 0.08	c22	4.60 ± 0.21	E2	3.58 ± 0.19	G23	0.95 ± 0.05	ν12	0.36 ± 0.01
v33	1.53 ± 0.01	c33	3.25 ± 0.18	E3	2.73 ± 0.19	G13	0.68 ± 0.04	ν31	0.28 ± 0.02
v12/12	0.90 ± 0.02	c44	0.95 ± 0.05					ν13	0.31 ± 0.02
v23/23	0.93 ± 0.01	c55	0.68 ± 0.04					ν23	0.17 ± 0.03
v13/13	0.97 ± 0.03	c66	0.86 ± 0.03					ν32	0.13 ± 0.02
v12	0.79 ± 0.01	c12	1.99 ± 0.05
v23	0.83 ± 0.02	c23	1.39 ± 0.02
v13	0.70 ± 0.03	c13	1.12 ± 0.05

v: ultrasound velocities that were measured directly by ultrasonic method; v₁₁, v₂₂, v₃₃, v_12/12, v_23/2X, v_13/13 were longitudinal wave speed measured with the generation and sensing transducer in line, and v₁₂, v₂₃, v₁₃ were the transverse wave speed measured with the generation and sensing transducer at a right angle. c: elastic coefficients that were calculated from v. E (Young's modulus), G (Shear modulus), and ν (Poisson's ratio) were calculated from c and would be further applied into the finite element analysis for material definition of the condyle. For subscript numbers of v, E, G, and ν. 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 c did not the indicate directions, which were just the calculation results from vij and further for calculating the technical constants.