Preshearing method for the control of the rheology and the injectability of aqueous inorganic cements

A method of controlling aqueous inorganic cements in surgical procedures, the method comprising:

• characterizing setting kinetics by monitoring variations of dynamic rheological properties of aqueous inorganic cement with respect to time, temperature, and shearing conditions after quiescent periods in a rotational rheometer;
• the rotational rheometer having an ability to generate steady and oscillatory torsion;
• pinpointing a characteristic linear viscoelastic strain or stress limit, dough time, initial setting time, and final setting time;
• subjecting a cement paste to preshearing periods of various oscillatory preshearing frequencies at a strain or stress amplitude lower than a predetermined linear viscoelastic strain or stress limit;
• measuring the dynamic rheological properties at an end of the preshearing periods;
• comparing the dynamic rheological properties of the cement paste at the end of the preshearing periods to the dynamic rheological properties of the quiescently tested cements;
• pinpointing a characteristic setting promoting frequency limit;
• applying a time dependent preshearing period to the cement paste with the facility of a drag flow mechanism comprising a screw in contact with the cement paste, that can independently rotate in both a clockwise direction and a counterclockwise direction and can alternate between rotation in the clockwise direction and the counterclockwise direction in a cyclic manner, to promote or delay setting of the cement paste by adjusting oscillatory strain amplitude and frequency;
• delivering the cement paste to a surgical site after application of the time dependent preshearing period.