FIG. 1 is a right front perspective view of a toothbrush according to the new design;

FIG. 2 is a left front perspective view thereof;

FIG. 3 is a right rear perspective view thereof;

FIG. 4 is a left rear perspective view thereof;

FIG. 5 is a front view thereof;

FIG. 6 is a rear view thereof;

FIG. 7 is a right side view thereof;

FIG. 8 is a left side view thereof;

FIG. 9 is a top view thereof;

FIG. 10 is a bottom view thereof;

FIG. 11 is an enlarged front view of the head thereof; and,

FIG. 12 is an enlarged rear view of the head thereof.

The broken lines showing a handle and the remainder of the brush head illustrate portions of the toothbrush that form no part of the claimed design.