Toothbrush head with bristles

FIG. 1 is a perspective view of my ornamental design for a toothbrush head with bristles;

FIG. 2 is a bottom plan view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a side elevational view thereof, the opposite side being a mirror image;

FIG. 5 is an end view thereof as seen from the left side of FIG. 3; and,

FIG. 6 is an end view thereof as seen from the right side of FIG. 3.

The structure shown in phantom or broken lines in the FIGS. forms no part of the claimed design and is included only to illustrate an environment.