RADIOLOGY & PHOTOGRAMMETRY - Photogrammetric Principles as Applyed in the Periapical Intra-oral Radiology: an evaluation of the accuracy and method reproducibility

Abstract

The objective of this study was to evaluate the accuracy and reproducibility of
photogrammetric principles and techniques over periapical radiographic images.
Twelve stereoscopic radiographic pairs were obtained by means of an Auxiliary
Aiming Device (AAD) fixed to a human jaw. The best angle of convergence to
allow stereoscopy was verified to be 20°. The radiograph images were digitalized
on a photogrammetric scanner and the data transferred to a computer memory. For
each pair of images, ten readings of the coordinates of a same point were recorded.
The precision obtained for the measurements of X, Y, Z coordinates were
respectively 3 µm, 3 µm and 18 µm. The reproducibility of the experiment was
possible due to the high rigidity and stability of the device created to hold the X-ray
instrument in the right position. The method shows to be high accurate for radiodiagnosis
in three-dimensional periapical radiographic images.