Introduction & Objective: Diagnosis of periodontal osseous lesions is very important in deter-mining prognosis, treatment plan and maintenance in the long term. This diagnosis can be achieved by using radiography. The aim of this study is to compare accuracy of E speed films, bitewing PSP, panoramic PSP and CCD for identifying the extent of destruction of alveolar bone in chronic periodontitis.

Materials & Methods: In this cross-sectional study, 272 interproximal surfaces were evaluated by 4 radiographic techniques after clinical examination by a periodontist and indication of flap surgery. The distance between CEJ and the alveolar crest was measured by Williams probe during the surgery and before osseous recontouring. These measures were considered as gold standard. This distance was measured using all 4 radiography techniques by 2 radi-ologists at standard conditions after calibration.

Results: There was no significant difference between the 4 techniques. The mean distances from CEJ to alveolar crest in all techniques had no significant difference with gold standard, the least difference was in digital BW PSP and the greatest difference was in panoramic PSP. The non-measurable surfaces by E speed BW and panoramic PSP were the fewest and the most, respectively.

 Conclusion: Better relative accuracy with regard to variation range, mean difference of measures based on gold standard and number of shown surfaces was observed in digital and conventional BW compared to digital panoramic images.