Hollow glass waveguide: x-ray image in root canal system

Objective of the study was the evaluation of X-ray image quality of cyclic olefin polymer-coated silver hollow glass waveguide (COP/Ag) in root canal, using a dental digital radiography method for an endodontic treatment. Er:YAG laser system was used. The wavelength generated was 2.94 micrometers and the length of the generated pulses was around 250 usec. The radiation was delivered to the investigated tissue by a cyclic olefin polymer-coated silver hollow glass waveguide (COP/Ag) with an inner diameter equal to 700 micrometers and the length of 10 cm. The fluence used in the experiments was in the range of 19 up to 45 J/cm2. The root canal systems of 10 extracted premolars and molars were treated endodontically using a step-back technique with K-type endodontic files. Isometric X-ray images were captured via fixed-point measurement method. Digital images were taken before treatment, with conventional files and with an insertion of the COP/Ag hollow glass waveguide. A density histogram, characterizing the density spread across the image was established. An aluminum step wedge, 50 mm long x 20 mm wide, having thickness range from 0.5 mm to 5 mm was used as a marker to check the quality of radiopacity. The overall dimensions were adjusted in relation to the sensor size as a control. COP/Ag hollow glass waveguide was slightly visible in root canal system. An isometric image, histogram, and pseudocolor picture help to detect the position of waveguide in the root canal.