Evaluation of a technique for standardized periapical radiographs

Abstract A paralleling instrument with an orientation bite-block was designed to provide standardized projections on periapical radiographs with the extension cone paralleling technique. The reproducibility of root images on these radiographs and the relocation of the orientation bite-block in relation to root structures were tested in five patients. Three radiographs were subsequently made of each patient and compared. The projection error proved to be negligible.