Toothbrush head

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

FIG. 2 is a top view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a left side elevational view thereof;

FIG. 6 is a distal end elevational view thereof as viewed from the left side of FIG. 2; and,

FIG. 7 is a proximal end elevational view therof as viewed from the right side of FIG. 2.

The broken line showing is for illustrative purposes only and forms no part of the claimed design.