the effect of x–ray vertical angulation on radiographic assessment of alveolar bone loss

introduction radiographs provide unique information about the status of periodontium and permanent records of condition of bone throughout the course of the disease. interproximal images record the distance between the cementoenamel junction and the crest of the interradicular alveolar bone, more accurately. the aim of this study was to investigate the effect of different vertical angles of x-ray tube (0, -10, +10) degrees in horizontal and vertical bite wing techniques in assessment of bone loss. methods: one hundred and twenty bitewing radiographs from 150 interproximal surfaces from 10 dried skull were by three degrees (0, -10, +10) prepared. the level of alveolar bone loss was measured using ruler on the skulls and radiographs and data were registered. type of bone loss was horizontal. results the maximum differences between invitro and radiographic findings were +3 and -2.745 mm. in all areas, radiographic data were less than clinical diameters. in all areas, by using zero degree vertical angulation, there was less difference between mean of radiographics and clinical measurements. conclusions with changing vertical angulations, using 0, +10, and -10 degrees, a wide range of measures (2.75-3mm) in amount of alveolar bone loss were ohtained for evaluating periodontal disease or following them up, accurate and reproducible images are necessary. in this study we concluded that zero vertical angulation degree decrease the angulation errors and reduce understimation of radiographic assessment of alveolar bone loss.