A Developmental Study of Automatic Canal Filing System

本研究总体上涉及用于治疗根管的牙科设备，尤其涉及用于在自动扩大根管的同时检测根管的根尖部分的系统。在传统的电气设备中，如果根管被液体药物或血液润湿，这种检测是困难的。根据本研究，具有不同频率的两个输入信号被叠加。得到在阻抗几乎不可能变化的根管中的给定位置处对应于两个不同频率的阻抗之间的差值。该值和临床确定的值用于检测根管的根尖部分。这种新装置的特点如下：(1)该装置能够准确地检测根管中的任何位置，甚至根尖孔中因液体药物或血液的存在而阻抗变化很大的位置。因此，在扩大根管的同时，该系统在任何条件下都是完全可操作的。(2)根尖孔直径对指标值影响不大。(3)根管电极的大小对指标值影响不大。(4)临床使用的次氯酸钠浓度对指标值影响不大。该装置与电机、超声波、亚音速等机械设备相结合，可实现自动根管预备。

The present study relates generally to dental equipments for treating a root canal and in particular, to a system for detecting the apical portion of a root canal while automatically enlarging the root canal. Such detection has been difficult if the root canal is moisturized with liquid medicines or blood, in conventional electrical equipments.In accordance with the present study, two input signals having different frequencies are superposed. The difference between impedances corresponding to the two different frequencies at a given position in the root canal where the impedances may hardly vary, is obtained. This value and a clinically determined value are used to detect the apical portion of the root canal.1. Characteristic features of this new device were as follows: (1)This device is capable of accurately detecting any position in the root canal, even the potion of the apical foramen where impedances may vary widely due to the presence of liquid medicines or blood. The system is, therefore,fully operable under any condition while enlarging the root canal. (2)Diameters of the apical foramen showed little influence on the indicated value. (3)The size of the root canal electrode showed little influence on the indicated value. (4)The concentrations of sodium hypochlorite clinically employed showed little influence on the indicated values.2. Automatic root canal instrumentation may be carried out by combination of this new device and mechanical equipment, such as electrical engine, ultrasonic and subsonic.