Unitary, one-piece plastic molded micro-brushes are provided to remove the smear layer that remains in the root canal and access chamber after the pulp, bacteria, and related irritants have been mechanically and chemically removed from the root canal and access chamber using rotary cutting burs, files and various chemical reagents. The brushes include a handle, shaft or shank and a tapered brush section extending from the distal end of the shank. The brush section includes a plurality of bristles extending radially from a core. The bristles of the root canal brush can be formed in a reverse thread pattern. The brush section of the root canal brush has a diameter of between about 0.1 mm and about 0.2 mm at a tip end and a diameter of between about 0.5 mm and 3 mm at a coronal-most end. The brush section of the root canal brush is about 16 mm long, and has a taper of about 2% to about 12%. In the access chamber brush, the core can be formed as to be spherical, football-shaped, or tapered. The brushes are injection molded from an FDA approved resin.
