ABSTRACT
Through the analysis on principles of dental panoramic radiography, we analyzed the influence factors of the dental arch, and provided the main principles for optimizing design to improve the image quality. Through the analysis on the human dental arch’s form, we optimized the radiographic procedure. Many factors affect the quality panoramic image, but the focal trough’s design is one of the most important factors, especially for canine regions. Optimizing design of focal trough can lessen degrees of horizontal and vertical magnification, also can reduce geometric distortion and overlapped images of teeth.
ABSTRACT
PURPOSE: To make a focal trough (image layer) for an average maxillary dental arch of 6-year-old korean in panoramic radiography. MATERIALS AND METHODS: Phantom for the maxillary dental arch was designed using intercanine width, intermolar width, tooth size, and interdental spacing to record the data of 6-year-old child. The characteristics of pre-corrected panoramic machine (for adult) was evaluated using the phantom, resolution test pattern for margin of the image layer, and metal ball for the center of the image layer. Panoramic image layer of the child was developed by means of decreasing the speed of film-cassette and positioning the phantom backwards, and then the characteristics of post-corrected panoramic machine (for child) were reevaluated. RESULTS: At post-corrected panoramic image layer, beam projection angles at all interdental areas increased for about 2.6-3.8 degrees, the position of the image layer was shifted toward the rotation center for about 2.5 mm at the deciduous central incisior area. The width of image layer decreased at all areas. CONCLUSION: Increased beam projection angle will reduce the disadvantage of tooth overlap, and the same form between the center of the image layer and dental arch will improve image resolution.