Objective: To design a reliable method for standardized paralelling dental projection, for comparison of the tiny variations of alveolar bone during the treatment of the periodontal disease.
Methods and material: Periapical radiographs in 29 pairs of films with this device and 14 pairs of films with traditional method on dried skulls were comparatively analysed by digital subtraction. Standard deviations and angle variations of subtracted image were studied comparatively between this method and traditional paralleling technique.
Results: Significant difference of reproducibility between two groups was showed. The reproducibility of the successive pictures was apparently increased when projected with positioning device.