Development of a device for determining the root canal contamination

本研究的目的是设计一种通过分析根管壁反射光的颜色来判断根管污染的装置。1.对扩大的根管壁和肮脏的根管壁的反射光进行光谱分析。放大管壁的光谱特征与光源的相似，而脏管的光谱在600 nm以上有增强的趋势。2.测量了放大管壁和脏管壁在560 nm和650 nm处的反射光强度。3.研制了一种根管污染检测装置，并对其临床适用性进行了检验。光源为白光，使用光学探头沿其长轴横向照射和收集反射光。该装置利用两个光电二极管同时测量560 nm和650 nm的光强并进行比较，通过输出信号的极性和幅度来表示样品反射光的颜色。用蓝色色板、白色色板和清洁牙面得到的输出的极性是相同的。然而，红色色板和肮脏的牙齿表面产生的极性与清洁牙齿表面的相反。当牙面染成红色时，获得了较大的输出信号幅值，表明该实验装置可以发展成为一种根管污染检测装置。通过对检测系统的改进，如波长的选择、激光的使用、信号处理的改变、牙齿的染色等，可以提高检测系统的性能。

The purpose of this study was to design a device which determines the root canal contamination by analyzing the color of the reflected light from the canal wall.1.The spectrum analysis was made with the reflected light from the enlarged canal wall and the dirty one. The spectrum pattern with the enlarged canal wall was similar to that obtained with the light source, while that with the dirty one showed a tendency of the increased light intensity at wavelengths longer than 600nm.2.The reflected light intensities at 560nm and 650nm were measured on the enlarged canal wall and the dirty one. There was a difference of the ratio of the light intensities at these wavelengths between the enlarged and the dirty.3.A trial device for determining the root canal contamination was made, and its clinical applicability was examined. The light source was a white light, and an optical probe which illuminated and collected the reflected light laterally to its long axis was used. The device simultaneously measured the light intensities at 560nm and 650nm using 2 photo-diodes and compared them at the same time, and expressed the color of the reflected light from the sample by the polarity and amplitude of the output signal. The polarity of the output was the same between those obtained with a blue color board, a white color board, and a clean tooth surface. While, a red color board and a dirty tooth surface produced the opposite polarity to that obtained with the clean tooth surface. A large output signal amplitude was obtained when the tooth surface was dyed red.The results obtained in this study indicated that the trial device could develop as a root canal contamination detector. The detection system could improve with the modification of the system such as the selection of wavelengths of the light, use of a laser light, the alteration of the signal processing, and dying the tooth.