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PMMA

 

Polymethylmethacrylate (PMMA): bone cement Propertieis

  • no adhesive properties.  Works as grout, not glue.
  • does not chemically bond to bone or implants
  • three times stronger in compression than tension.
  • peak blood levels of monomer occur 3 minutes after the cement is placed.
  • monomer is cleared by the lungs.
  • hypotension associated with cement is more closely related to diminished blood volume than to circulating monomer levels.
  • Higher porosity = decreased tensile and fatigue strength. Manually mixed = 27%. Vacuum mixed = 1%
  • Antibiotics in cement does not appreciably affect compressive or tensile forces.  Fatigue strength may be reduced.