Contd: Human dental calculus

After 18 hours…

(1)Centrifuge (13.5x1000rpm, 3 mininutes) => supernatant pipetted

(2)Adding 40μl of distilled water => centrifuge (13.5x1000rpm, 3 mininutes) => supernatant pipetted
*Repeating twice.

(3)Drying the extract (at the room temperature).