Abstract: A measuring handle for treating dental root canals comprises a handle in which an instrument slides longitudinally. The guide hook of the instrument engages in a helical screw rotatably mounted in the handle and is guided longitudinally in a longitudinal slot in the handle. The handle is expanded at its rotating end to form a gripping head in which is arranged a cylindrical mounting space for a rotary body of a rotary handle which actuates the helical screw. A section of the longitudinal slot expands through the rotary handle into the gripping head and is covered in the region of said slot, so that, in a development of the handle having an additional gripping head at the end nearer the instrument, the head can be firmly gripped when gloves are worn or the handle is wet with water or saliva.

Abstract: In a manually operated instrument such as a root-canaling instrument, a security cord (10) is attached at one end to the handle (1) of the instrument by means of a mounting shell (5), which can be snapped onto and seated against the handle from the shaft end of the instrument, and at the other end to a ring (13) on the operating dentist's finger.The security cord (10) is attached to the finger ring (13) with a wrapping or clamping device (15) and can be released.

Abstract: A gauge for positioning a stop on a root-canal instrument is formed at one end with a handle and at the opposite end with a groove passing through a seat. The shaft of a root-canal instrument is seated in the groove with a stop fitted thereover lying in the seat. The shaft is then displaced relative to the stop and the seat such that its point travels along a scale starting at the edge of the seat so that the exact distance between the point and the stop can be determined. In addition the base plate forming this gauge is provided with a plurality of sockets each releasably holding a stop and is formed with a set of throughgoing gauge holes. Thus the dentist may ascertain with these gauge holes the diameter of the shaft of his root-canal instrument and then choose an appropriately sized stop from a selection thereof carried directly on the gauge in the sockets.

Abstract: A stop to prevent the insertion of the shaft of a root-canal instrument too far into a tooth comprises a housing formed with a throughgoing passage and a compression spring in the passage having an inner diameter smaller than the outer diameter of the shaft. This stop is slipped over the shaft and the spring tightly grasps the shaft so as to impede sliding of the stop therealong. The compression spring may be loosely received within a chamber formed within the housing, or may be imbedded in a block of synthetic-resin material constituting the housing. A two-part housing may be used one part of which is connected to one end of the spring and the other part of which is connected to the other end of the spring so that rotation of these two parts relative to each other allows the spring to be loosened from the shaft to allow easy sliding of the stop therealong.