The ornamental design for a dentalhandpiecemaintenancemachine, as shown and described.
FIG. 1 is a front view of a dental handpiece maintenance machine of Embodiment 1 of the present design;
FIG. 2 is a rear view thereof;
FIG. 3 is a right side view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a top view thereof;
FIG. 6 is a bottom view thereof; and,
FIG. 7 is a perspective view thereof.
The broken lines shown in the drawings represent portions of the dental handpiece maintenance machine that form no part of the claimed design. The long dashed and short dashed lines indicated only boundaries between the portions sought to receive design registration as the claimed design and unclaimed design.