This study was designed to compare the compressive mechanical properties of filler materials, Wood’s metal, dental stone, and polymethylmethacrylate (PMMA), which are widely used for performing structural testing of whole vertebrae. The effect of strain rate and specimen size on the mechanical properties of the filler materials was examined using standardized specimens and mechanical testing. Because Wood’s metal can be reused after remelting, the effect of remelting on the mechanical properties was tested by comparing them before and after remelting. Finite element (FE) models were built to simulate the effect of filler material size and properties on the stiffness of vertebral body construct in compression. Modulus, yield strain, and yield strength were not different between batches (melt-remelt) of Wood’s metal. Strain rate had no effect on the modulus of Wood’s metal, however, Young’s modulus decreased with increasing strain rate in dental stone whereas increased in PMMA. Both Wood’s metal and dental stone were significantly stiffer than PMMA (12.7±1.8GPa, 10.4±3.4GPa, and 2.9±0.4GPa, respectively). PMMA had greater yield strength than Wood’s metal (62.9±8.7MPa and 26.2±2.6MPa). All materials exhibited size-dependent modulus values. The FE results indicated that filler materials, if not accounted for, could cause more than 9% variation in vertebral body stiffness. We conclude that Wood’s metal is a superior moldable bonding material for biomechanical testing of whole bones, especially whole vertebrae, compared to the other candidate materials.

1.
Liebschner
,
M. A.
,
Kopperdahl
,
D. L.
,
Rosenberg
,
W. S.
, and
Keaveny
,
T. M.
, 2003, “
Finite Element Modeling of the Human Thoracolumbar Spine
,”
Soins Pathol. Trop.
0222-9307,
28
, pp.
559
565
.
2.
Kopperdahl
,
D. L.
,
Pearlman
,
J. L.
, and
Keaveny
,
T. M.
, 2000, “
Biomechanical Consequences of an Isolated Overload on the Human Vertebral Body
,”
J. Orthop. Res.
0736-0266,
18
, pp.
685
690
.
3.
Lewis
,
G.
, 1997, “
Properties of Acrylic Bone Cement: State of the Art Review
,”
J. Biomed. Mater. Res.
0021-9304,
38
, pp.
155
182
.
4.
Yeni
,
Y. N.
,
Patel
,
B.
,
Fyhrie
,
D. P.
, and
Cody
,
D. D.
, 2003, in
49th Annual Meeting, Orthopaedic Research Society 1091
,
New Orleans
, Louisiana.
5.
ASTM
, 2002, “
D695–02a Standard Test Method for Compressive Properties of Rigid Plastics
,”
Annual Book of ASTM Standards
,
08.01
.
6.
Hou
,
F. J.
,
Lang
,
S. M.
,
Hoshaw
,
S. J.
,
Reimann
,
D. A.
, and
Fyhrie
,
D. P.
, 1998, “
Human Vertebral Body Apparent and Hard Tissue Stiffness
,”
J. Biomech.
0021-9290,
31
, pp.
1009
1015
.
7.
Kim
,
D.-G.
,
Hunt
,
C. A.
,
Zauel
,
R.
,
Fyhrie
,
D. P.
, and
Yeni
,
Y. N.
, 2005, in
51st Annual Meeting, Orthopaedic Research Society
, Washington, DC, p.
681
.
8.
Hoffler
,
C. E.
,
Moore
,
K. E.
,
Kozloff
,
K.
,
Zysset
,
P. K.
,
Brown
,
M. B.
, and
Goldstein
,
S. A.
, 2000, “
Heterogeneity of Bone Lamellar-Level Elastic Moduli
,”
Bone (N.Y.)
8756-3282,
26
, pp.
603
609
.
9.
Rho
,
J. Y.
,
Tsui
,
T. Y.
, and
Pharr
,
G. M.
, 1997, “
Elastic Properties of Human Cortical and Trabecular Lamellar Bone Measured by Nanoindentation
,”
Biomaterials
0142-9612,
18
, pp.
1325
1330
.
10.
Jacobs
,
C. R.
,
Davis
,
B. R.
,
Rieger
,
C. J.
,
Francis
,
J. J.
,
Saad
,
M.
, and
Fyhrie
,
D. P.
, 1999, “
NACOB Presentation to ASB Young Scientist Award: Postdoctoral. The Impact of Boundary Conditions and Mesh Size on the Accuracy of Cancellous Bone Tissue Modulus Determination Using Large-Scale Finite—Element Modeling. North American Congress on Biomechanics
,”
J. Biomech.
0021-9290,
32
, pp.
1159
1164
.
11.
Kuhn
,
J. L.
,
Goldstein
,
S. A.
,
Choi
,
K.
,
London
,
M.
,
Feldkamp
,
L. A.
, and
Matthews
,
L. S.
, 1989, “
Comparison of the Trabecular and Cortical Tissue Moduli from Human Iliac Crests
,”
J. Orthop. Res.
0736-0266,
7
, pp.
876
884
.
12.
Choi
,
K.
,
Kuhn
,
J. L.
,
Ciarelli
,
M. J.
, and
Goldstein
,
S. A.
, 1990, “
The Elastic Moduli of Human Subchondral, Trabecular, and Cortical Bone Tissue and the Size-Dependency of Cortical Bone Modulus
,”
J. Biomech.
0021-9290,
23
, pp.
1103
1113
.
13.
Zysset
,
P. K.
,
Guo
,
X. E.
,
Hoffler
,
C. E.
,
Moore
,
K. E.
, and
Goldstein
,
S. A.
, 1999, “
Elastic Modulus and Hardness of Cortical and Trabecular Bone Lamellae Measured by Nanoindentation in the Human Femur
,”
J. Biomech.
0021-9290,
32
, pp.
1005
1012
.
14.
van Rietbergen
,
B.
,
Weinans
,
H.
,
Huiskes
,
R.
, and
Odgaard
,
A.
, 1995, “
A New Method to Determine Trabecular Bone Elastic Properties and Loading using Micromechanical Finite-Element Models
,”
J. Biomech.
0021-9290,
28
, pp.
69
81
.
15.
Hicsasmaz
,
Z.
, and
Rizvi
,
S. S. H.
, 2005, “
Effect of Size and Shape on Modulus of Deformability
,”
Food Sci. Technol. (London)
0023-6438,
38
, pp.
431
435
.
16.
Li
,
X. X.
,
Ono
,
T.
,
Wang
,
Y. L.
, and
Esashi
,
M.
, 2003, “
Ultrathin Single-Crystalline-Silicon Cantilever Resonators: Fabrication Technology and Significant Specimen Size Effect on Young’s Modulus
,”
Appl. Phys. Lett.
0003-6951,
83
, pp.
3081
3083
.
17.
Li
,
Q. B.
,
Zhang
,
F. D.
,
Zhang
,
W. C.
, and
Yang
,
L. C.
, 2002, “
Fracture and Tension Properties of Roller Compacted Concrete Cores in Uniaxial Tension
,”
Ann. Soc. Sci. Bruxelles, Ser. 1
0037-959X,
14
, pp.
366
373
.
18.
Lund
,
J. R.
, and
Byrne
,
J. P.
, 2001, “
Leonardo da Vinci’s Tensile Strength Tests: Implications for the Discovery of Engineering Mechanics
,”
Civ. Eng. Environ. Syst.
1028-6628,
18
, pp.
243
250
.
19.
Edwards
,
L. K.
,
Lakes
,
R. S.
, and
Nixon
,
W. A.
, 2000, “
Viscoelastic Behavior of 80In15Pb5Ag and 50Sn50Pb Alloys: Experiment and Modeling
,”
J. Appl. Phys.
0021-8979,
87
, pp.
1135
1140
.
20.
Enikeev
,
F. U.
, and
Mazurski
,
M. I.
, 1995, “
Determination of the Strain-Rate Sensitivity of a Superplastic Material During Load Relaxation Test
,”
Scr. Metall. Mater.
0956-716X,
32
, pp.
1
6
.
21.
Vasin
,
R. A.
,
Enikeev
,
F. U.
, and
Mazurski
,
M. I.
, 1997, “
Determination of the Strain Rate Sensitivity of a Superplastic Material at Constant Load Test
,”
Mater. Sci. Eng., A
0921-5093,
224
, pp.
131
135
.
22.
Vasin
,
R. A.
,
Enikeev
,
F. U.
, and
Mazurski
,
M. I.
, 1998, “
Method to Determine the Strain-Rate Sensitivity of a Superplastic Material from the Initial Slopes of Its Stress Strain Curves
,”
J. Mater. Sci.
0022-2461,
33
, pp.
1099
1103
.
23.
Vasin
,
R. A.
,
Enikeev
,
F. U.
,
Mazurski
,
M. I.
, and
Munirova
,
O. S.
, 2000, “
Mechanical Modelling of the Universal Superplastic Curve
,”
J. Mater. Sci.
0022-2461,
35
, pp.
2455
2466
.
24.
Dai
,
Y.
,
Barbagallo
,
F.
, and
Groeschel
,
F.
, 2003, “
Compression Properties of Lead-Bismuth
,”
J. Nucl. Mater.
0022-3115,
317
, pp.
252
255
.
25.
Kamal
,
M.
, and
El-Bediwi
,
A. B.
, 2000, “
Structure, Mechanical Metallurgy and Electrical Transport Properties of Rapidly Solidified Pb50Sn50‐xBix Alloys
,”
J. Mater. Sci.: Mater. Electron.
0957-4522,
11
, pp.
519
523
.
26.
Kamal
,
M.
,
El-Blediwi
,
A. B.
, and
Karman
,
M. B.
, 1998, “
Structure, Mechanical Properties and Electrical Resistivity of Rapidly Solidified Pb–Sn–Cd and Pb–Bi–Sn–Cd Alloys
,”
J. Mater. Sci.: Mater. Electron.
0957-4522,
9
, pp.
425
428
.
27.
Evans
,
G. P.
,
Behiri
,
J. C.
,
Vaughan
,
L. C.
, and
Bonfield
,
W.
, 1992, “
The Response of Equine Cortical Bone to Loading at Strain Rates Experienced In Vivo by the Galloping Horse
,”
Equine Vet. J.
0425-1644,
24
, pp.
125
128
.
28.
Fyhrie
,
D. P.
,
Milgrom
,
C.
,
Hoshaw
,
S. J.
,
Simkin
,
A.
,
Dar
,
S.
,
Drumb
,
D.
, and
Burr
,
D. B.
, 1998, “
Effect of Fatiguing Exercise on Longitudinal Bone Strain as Related to Stress Fracture in Humans
,”
Ann. Biomed. Eng.
0090-6964,
26
, pp.
660
665
.
29.
Burr
,
D. B.
,
Milgrom
,
C.
,
Fyhrie
,
D. P.
,
Forwood
,
M.
,
Nyska
,
M.
,
Finestone
,
A.
,
Hoshaw
,
S.
,
Saiag
,
E.
, and
Simkin
,
A.
, 1996, “
In Vivo Measurement of Human Tibial Strains During Vigorous Activity
,”
Bone (N.Y.)
8756-3282,
18
, pp.
405
410
.
You do not currently have access to this content.