The ornamental design for an interdentalbrush, as shown and described.
FIG. 1 is a perspective view of an interdental brush, showing our new design;
FIG. 2 is a front view, the rear view is a mirror image thereof;
FIG. 3 is a top plan view thereof;
FIG. 4 is a bottom plan view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is an enlarged perspective view of the brush portion thereof;
FIG. 8 is an enlarged front view of the brush portion, the enlarged rear view of the brush portion is a mirror image thereof, and the enlarged top plan view of the brush portion and the enlarged bottom plan view of the brush portion are identical thereto;
FIG. 9 is an enlarged left side view of the brush portion thereof;
FIG. 10 is an enlarged right side view of the brush portion thereof; and,
FIG. 11 is a transverse cross-sectional view of the brush portion thereof.
The broken lines in the drawings illustrate portions of the interdental brush that form no part of the claimed design.