I claim the ornamental design for the toothbrush handle, as shown and described.
FIG. 1 is a front perspective view of the toothbrush handle of the present invention, showing the placement of a toothbrush head attached thereto in broken lines.
FIG. 2 is a front perspective view of the present invention.
FIG. 3 is a front elevation view thereof.
FIG. 4 is a rear elevation view thereof.
FIG. 5 is a right side elevation view thereof.
FIG. 6 is a left side elevation view thereof.
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
The toothbrush head shown in FIG. 1 in broken lines illustrates environmental structure. The dashed lines in FIGS. 2-7 illustration portions of the article that form no part of the claimed design.