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 top view thereof;

FIG. 10 is a bottom view thereof;

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

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

FIG. 13 is an enlarged right side view of the head thereof.

The dash-dot-dash line shown in FIGS. 1-8 and 11-13 represents an unclaimed boundary. The dashed broken lines showing a handle illustrate environmental structure of the toothbrush that along with the unclaimed boundary, form no part of the claimed design.