A dental hand piece with replaceable tips at either end of a tubular handle, each of the replaceable tips including a tip assembly having an instrument working tip end at a distal end of a main tip body and a shank extending from the instrument working tip end to a proximal end of the main tip body. The tip assembly may be provided with a flat-blade extension end at the proximal end of the main tip body. The flat-blade extension end passes through a keyway-shaped slot provided in a locking component, and engages locking structure provided on a cylindrical barrel member. Replaceable tips at the ends of the tubular handle may be secured in 180° orientation to one another. A spring arm member may additionally or alternatively engage notches along an interior wall of the cylindrical barrel member.