The ornamental design for a dentalhandpiece, as shown and described.
FIG. 1 is a front elevation of a dental handpiece showing my new design with the cord member shown in fragment for ease of illustration, the side opposite being a mirror image;
FIG. 2 is a right side elevation thereof;
FIG. 3 is a left side elevation thereof;
FIG. 4 is a plan elevation thereof;
FIG. 5 is a bottom elevation thereof;
FIG. 6 is an enlarged right side elevation thereof;
FIG. 7 is an enlarged left side elevation thereof;
FIG. 8 is an enlarged front view thereof leftward of line A—A in FIG. 1;
FIG. 9 is a perspective view thereof; and,
FIG. 10 is a referential view thereof, showing the full cord.
The broken lines shown in FIG. 10 illustrate environment and form no part of the claimed design.