A system includes a handpiece and a removable tool assembly including a holder body, a shaft, a cutting bur, a guard, and a sleeve. The body engages the handpiece and defines a bore. The shaft extends within the bore and the bur is provided to the distal end of the shaft. The guard is coupled to the body via a threaded mating at the bore, such that rotation of the guard relative to the body longitudinally displaces the guard. The extends within the bore of the body and the guard. The guard is positioned relative to the body by a distance to define a working length of the bur between the distal end of the guard and the distal tip of the bur. The working length of the bur is used to cut tissue, without concern that cutting will be deeper than intended.
