We claim the ornamental design for a dental instrument, as shown and described.
FIG. 1 is a top, right side, rear and bottom perspective view of a dental instrument.
FIG. 2 is a front elevation view thereof.
FIG. 3 is a right side elevation view thereof, the left side being a mirror image.
FIG. 4 is a top, right side, rear and bottom perspective view of a second embodiment thereof.
FIG. 5 is a front elevation view of FIG. 4.
FIG. 6 is a right elevation view of FIG. 4, the left side being a mirror image.
FIG. 7 is a top, right side and bottom perspective view of a third embodiment thereof.
FIG. 8 is front elevation view of FIG. 7; and,
FIG. 9 is a right elevation view of FIG. 7, the left side being a mirror image.
In each of the embodiments, the intersecting segments of the dental instrument are each rotationally symmetrical. In each of the embodiments, the proximal end of the dental instrument is unornamented and forms no part of the claimed design. The stippling at the distal end of the dental instrument in FIGS. 1-6 indicate an area of contrasting appearance.