This is particularly true for biological specimens that shrink considerably when exposed to normal a ospheric conditions. Therefore, it has always been a goal to find suitable preservation techniques, especially for anatomists.
Silicone is used for whole specimens and thick body and organ slices to obtain a natural look.
Epoxy resins are used for thin, transparent body and organ slices. Polyester-copolymer is exclusively used for brain slices to gain an excellent distinction of gray and white matter. Dehydration is achieved mainly by acetone because acetone also serves as the intermediary solvent during impregnation. Plastinated specimens are perfect for teaching, particularly for neuroanatomy. Silicone plastinated brains are useful because they can be grasped literally and they are almost everlasting.