The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 17, 1992
Filed:
Aug. 14, 1991
Chihiro Kobayashi, Chiba, JP;
Kazunari Matoba, Kyoto, JP;
Kabushiki Kaisha Morita Seisakusho, Kyoto, JP;
Abstract
An apical position detection apparatus for detecting an apical position depending on the change in the impedance between a measuring electrode inserted in a root canal and an oral electrode connected to a soft oral tissue, the apparatus being characterized in that it comprises a signal output means which applies measurement signals with different frequencies between the measuring electrode and the oral electrode and a relative ratio detection means for calculating the ratio of root canal impedance values obtained depending on the measurement signals, whereby the detection apparatus detects the apical position by sensing that an equivalent impedance decreases and that the ratio of the root canal impedance values changes as the leading edge of the measuring electrode approaches the apical position. A method for detecting the apical position by using this apparatus is also disclosed.