Steps: Dry teeth
 Apply disclosing solution with cotton tip applicator
 Rinse once
 Older plaque appears darker in color (blue)
 Examine each tooth surface and record plaque on surfaces along the cervical 1/3rd of the tooth.
 Compute PI score
Calculation: Count number of surfaces with plaque (numerator)
 Determine the total number of surfaces available (# of teeth X 4) (denominator)
 PI = (# of surfaces with plaque X 100) / (Total # of available surfaces)
 PI of less than or equal to 10% is recommended.
