Root canal reversible stop

Claim 1

A root canal file and reversible stop comprising A. an elongated member, 1. one end portion of said elongated member having cutting means thereon, 2. a handle fixed at the opposite end of said elongated member, and 3. an intermediate file portion between said cutting means and said handle, a. said handle having a shoulder adjacent said intermediate file portion, and B. a reversible stop member on said intermediate portion, said stop member comprising 1. an elongated hollow shank having an internal diameter substantially equal to the external diameter of said intermediate file portion, 2. a small stopping end comprising a peripherally continuous flange extending radially outwardly from one end of said shank and formed integrally therewith, a. said last-mentioned flange having a diameter greater than the diameter of said first-mentioned flange, and 4. a resilient holding section secured to and within said shank and extending entirely across the interior of said shank, a. said intermediate file portion piercing said holding section and being sNugly grasped thereby, b. one of said stopping end flanges being in close abutment with the shoulder of said handle, whereby the other of said stopping end flanges provides a stop surface precisely positioned at a known distance from the cutting end portion of said file, 5. said stop member being reversibly positioned on said intermediate file portion so that in a first position said small stopping end engages said handle shoulder and said large stopping end is adapted to engage the crown of a tooth to limit depth of penetration of said cutting means in the root canal of said tooth, and when said stop member is in a reversed position said large stopping end engages said handle shoulder and said small stopping end is adapted to engage the crown of a tooth and provide adequate space for simultaneous engagement of said crown by the small stopping end of a second similar file and stop member.