Background: The distinction between radicular cysts and apical granulomas is a matter of considerable importance in making a treament decision. Because there are no clearly defined radiographic criteria, the distinction is made on the grounds of size. However, it has been suggested that cysts can be distinguished from granulomas on the basis of their radiometric density. The results of previous studies have proved conflicting.To determine possibilities of application of digital radiography density measurements in differentiation of periapical granulomas and radicular cysts of inflammatory origin.Material and Methods: The material consisted of 355 digital periapical radiograms obtained using Digora, RVG and Dixi 2 digital radiography systems in patients aged 20 to 84, divided into two groups: 259 granulomas and 102 radicular cysts. By means of Digora 2.0 software there were measured maximum and minimum densities along a line, then there was calculated the difference between maximum and minimum density. The largest dimensions of the lesions were measured – perpendicular and parallel to the root canal axis.
Results: It was proved that to some extent it was possible to differentiate cystic granulomas and radicular cysts on the basis of the difference between maximum and minimum density in linear measurement – when the difference exceeded 85.6 the lesion was a cyst and when it was below 45.9 a granuloma was diagnosed.Conclusions: Combination of two criteria – the calculated difference between densities and the largest dimension of a lesion, increased diagnostic possibilities of radiological differentiation of granulomas and radicular cysts.

Keywords: Aged, 80 and over, Diagnosis, Differential, Periapical Granuloma - radiography, Radicular Cyst - radiography, Radiographic Image Enhancement