The ornamental design for a toothsculptinginstrument, as shown and described.
FIG. 1 is an isometric view of a tooth sculpting instrument showing the new design;
FIG. 2 is a top view thereof;
FIG. 3 is a right side view, the left side being a mirror image thereof;
FIG. 4 is a bottom view thereof;
FIG. 5 is a front view thereof; and,
FIG. 6 is a rear view thereof.
The broken lines shown in the figures are included for the purpose of illustrating portions of the tooth sculpting instrument and form no part of the claimed design.