Endodontic File Distance Circuit for Stopper-Based Working Length

The patent replaces the manual mechanical scale-reading system with an automated electronic distance measurement circuit. The circuit includes a ruler with conductive strips at marked positions, a conductive probe that contacts the ruler, and electronic components (operational amplifiers, ADC, microcontroller) that automatically calculate and display the distance from the stopper to the file tip. This substitution eliminates human reading errors and provides precise digital measurement of the working length.

The patent employs feedback through the electronic measurement system that continuously monitors the distance between the stopper and file tip. The conductive probe contacts the conductive strips on the ruler at the exact position of the stopper, and the electronic circuit calculates the distance based on which conductive strip is contacted. This feedback mechanism ensures accurate and consistent measurement without relying on manual positioning accuracy, as the system automatically detects the stopper position through electrical contact.

The electronic distance measurement circuit in the handle is designed to serve multiple functions: it measures the distance from the stopper to the file tip, calculates the working length, and can potentially measure other dimensions. The conductive ruler with multiple conductive strips can detect various positions along the file shaft, making the system versatile for different measurement needs while consolidating these functions into a single integrated device rather than requiring separate measurement tools.