Air inclusion in bone cement. Importance of the mixing technique.

The amount of air inclusion in bone cement (Simplex P) expressed as density and porosity was analyzed for five different mixing conditions: manual, mechanical, centrifuged manual, centrifuged mechanical, and mechanical in combination with vacuum. Mechanical mixing resulted in a cement of less porosity and increased density. Centrifugation did not further improve the cement. Mechanical mixing in combination with vacuum was superior to the other techniques in density and porosity.