US Patent 7347830 Assemblies and methods for measuring tooth apex location

The invention provides an assembly for measuring the penetration depth of a dental instrument into a root canal of a tooth. The assembly has a base element configured to be clampingly braced onto a tooth to be treated; an electrically conductive guiding member affixable to the base element and disposed, when assembled, above the tooth, thereby, in use, a portion of the dental instrument makes electrical contact with it. The guiding member further includes an electrical terminal connectable to an apex location measuring device. Methods for continuously measuring penetration depths of a dental instrument into a root canal of a tooth are also provided.