Monofilaments with split ends

Monofilaments with split ends. The monofilaments can be used to form toothbrush bristles having flagged or feathered tips. Each of the monofilaments has a plurality of internal fusion lines and at least four voids, wherein the voids comprise between 5 and 20% of the cross-sectional area of the monofilaments. Preferably, the monofilaments each have a diameter in a range of 0.0025 to 0.012 inches, and have a hexalocular or an octalocular configuration. The monofilaments are manufactured by extruding a plurality of thermoplastic polymeric streams, rotating a plurality of cutting blades above 1000 rpm, and placing a plurality of cutting blades in contact with end portions of the plurality of thermoplastic polymeric streams to form split ends.