FIG. 1 is a top, front, and left side perspective of a disposal dental handpiece showing our new design;

FIG. 2 is a right side elevational view thereof;

FIG. 3 is a left side elevational view thereof;

FIG. 4 is a front elevational view thereof;

FIG. 5 is a rear elevational view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof; and,

FIG. 8 us a bottom, rear, and right side perspective thereof.

The broken line showing of portions of the claimed design is included for the purpose of illustrating environmental structures and forms no part of the claimed design.