Patent ID: 7909604
Filing Date: 2011-03-22
Classification: A61C

Abstract:
1. A root apex position detection apparatus for detecting a root apex position of a root canal of a test tooth, comprising: a measurement electrode which is configured for insertion into the root canal; a mouth electrode which is configured for placement on an intraoral surface; a power supply which applies a plurality of types of measurement signals to one of the measurement electrode and the mouth electrode; a storage unit to store root apex position model data, intra-root-canal-position-specific model data, and predictive intra-root-canal-position-specific model data, (1) the root apex position model data having a plurality of model tooth data groups, each of the model tooth data groups comprising a plurality of impedance values between the measurement electrode and the mouth electrode with respect to each of the plurality of types of measurement signals while a distal end of the measurement electrode is placed at a root apex position of each model tooth, (2) the intra-root-canal-position-specific model data comprising a plurality of model tooth data groups, each of the model tooth data groups comprising a plurality of impedance values between the measurement electrode and the mouth electrode with respect to a plurality of types of measurement signals in a state in which the distal end of the measurement electrode is located at each of a plurality of predetermined positions in each of the model teeth, and (3) the predictive intra-root-canal-position-specific model data comprising a plurality of groups having impedance values predicted at a position midway between one predetermined position of a plurality of predetermined positions and the next predetermined position, and the model tooth including different model teeth for each model tooth data group; a signal switching unit to sequentially supply the plurality of types of measurement signals to one of the measurement electrode and the mouth electrode; a detection unit which sequentially detects a plurality of impedance values between the measurement electrode and the mouth electrode with respect to each of the plurality of types of measurement signals, in the process of inserting the measurement electrode into the root canal toward the root apex position, while sequentially applying each of the plurality of types of measurement signals to one of the measurement electrode and the mouth electrode; a comparison unit which compares each test tooth data group comprising the plurality of impedance values sequentially detected by the detection unit with each of the groups in the root apex position model data, intra-root-canal-position-specific model data, and predictive intra-root-canal-position-specific model data stored in the storage unit, detects that there is a group in a predetermined relationship with the test tooth data group, and outputs a detected result; and a display unit to display the detected result output from the comparison unit.