Abstract: An instrument particularly adapted for thermomechanically condensing a thermoplastic material such as gutta percha in the root canal of a tooth through the rotative action of the instrument is disclosed. The instrument comprises an elongated member including a shank at one end and a working portion at its other end. The working portion is tapered along at least part of its length. The working portion includes at least two oppositely disposed, continuous helical flutes formed in at least a portion of the tapered length of the shank defining at least two oppositely disposed helical shoulders. The shoulders face away from the shank and make an angle with the longitudinal axis of the working portion of from about 90.degree. to 80.degree. and each of the continuous spiraled flutes make from about 1.0 to 3.5 spirals per millimeter along the longitudinal axis of the working portion of the instrument.

Abstract: Disclosed is a dental tool for obturating stripped root canals, comprising an elongated rod-like body having a shank or handle and a working portion with radially outwardly extending shoulders or flutes facing away from the shank and making an angle with the longitudinal axis of the body of about 90.degree. or less. The diameter of the shoulders or flutes may be progressively diminished from adjacent the shank toward the end of the working portion to provide a taper, and in another embodiment the shoulders are continuous and spiraled. In use, the tool may be linearly and angularly reciprocally mounted in a power operator, and may be heated for softening the obturating materials, such a gutta-percha. The reciprocation of the tool, particularly the linear reciprocation, forces the shoulders into compressive contact with the softened material and, when adequate density is attained, backs out of the root canal naturally through reverse action without specific operator effort.

Abstract: A dental file is disclosed which is particularly useful in endodontia for removing dead or damaged tissue from a curved tooth root canal. The file has a flexible tapered shank which has a cutting surface on its periphery and a pilot projecting from the tapered end of the file for guiding the shank along the curved root canal preventing the cutting surface near the end of the shank from gouging into the wall of the curved root canal or penetrating too far through the apical foramen of the root canal.

Abstract: Disclosed is a dental file for use in cleaning out or extirpating root canals, particularly those which are curved, wherein the file which conventionally is provided with cutting or abrading flutes, typically in a spiraled manner, is also provided with a smooth, non-abrading pilot end which rides on the deep inner portion of the root canal wall and prevents the file from straightening out and causing the end thereof to "zip" or slice into the canal wall in an uncontrolled manner.