Evaluation of the panoramic image formation in different anatomic positions

Abstract

The aim of this study was to determine size, shape and position of the image layer by evaluation of the radiographic image formation in different anatomic positions. A customized phantom was made of a rectangular acrylic plate measuring 14 cm² and 0.3 cm thick, with holes spaced 0.5 cm away and arranged in rows and columns. Each column was separately filled with 0.315 cm diameter metal spheres to acquire panoramic radiographs using the Orthopantomograph OP 100 unit. The customized phantom was placed on the mental support of the device, with its top surface kept parallel to the horizontal plane, and was radiographed at three different heights from the horizontal plane, i.e., the orbital, occlusal and mandibular symphysis levels. The images of the spheres were measured using a digital caliper to locate the image layer. The recorded data were analyzed statistically by the Student's-t test, ANOVA and Tukey's test (α=0.05). When the image size of spheres in horizontal and vertical axes were compared, statistically significant differences (p<0.05) were observed in all areas, portions of the image layer and heights of horizontal plane evaluated. In the middle portion of the image layer, differences in the image size of spheres were observed only along the horizontal axis (p<0.05), whereas no differences were observed along the vertical axis (p>0.05). The methodology used in this determined the precise size, shape and position of the image layer and differences in magnification were observed in both the horizontal and vertical axes.

Influence of the intergonial distance on image distortion in panoramic radiographs

“…Hayakawa et al 24 reported the greatest distortions in the midline region. In the present study, the results were similar to those mentioned above 20,24 because the horizontal measurements in the incisor regions were also taken on both sides of midline in the radiographs.…”

“…These results could be related to the sample used, which by the mandibular shape established a specific position within the image layer of the X-ray machine. 20 Considering the independent analyses of vertical measurements, each region produced a different magnification, shown to be greater in the anterior and smaller in the posterior regions, similar to the results found in previous studies. 11,21 However, Sameshima and Asgarifar 16 observed the smallest magnification in the anterior and the greatest in the posterior region.…”

“…This distortion was induced because the central portion of the image layer in the anterior region was very thin, with insufficient width to accommodate it, 20 thus the mandible was in a position closer to the film or to the X-ray source depending on its anatomical shape. In a previous study 21 it was observed that when the horizontal measurements were made on the midline to assess bilateral structures of the anterior region, a greater magnification of measurements occurred.…”

Alterations and Pathologies Prevalence in Panoramic Radiographs in Patients Attending the University Dental Clinic

“…Since its introduction to the dental practice by Paatero in 1952, it has become an important diagnostic tool (Choi, 2011;Ladeira et al, 2010). The images that offers, allows us an overview of the maxillary structures and its teeth relationships.…”

Mosaic Evaluation: an Efficient and Robust Method based on Maximum Information Retrieval

“…Various parameter's evaluation and various system's ranking based on mosaic creation were proposed in literature like ranking of orientation tracking systems [9], ranking of electrooptical (EO) systems [10], Radiographic Quality [11], ranking of radiographic digital system [12], quality of size, shape and position of the image layer in radiographic panoramic images [13], quality of video compression [14] and ranking of tracking methods [15].…”