Forms of chronic periodontitis, treatment results and long-term results are traditionally defined on the basis of X-ray examination. Today, the most modern and reliable method for diagnostic X-ray examination opportunities in dentistry is dental cone-beam computed tomography. In comparison with other methods of X-ray examination in dentistry the method of dental cone-beam computed tomography has a number of advantages: the ability to make measurements of distances, the density of solid tissue, angles and areas in any part of the data at any angle, at any height, length, width up to 0,125 mm due to the fact that the area research scan 1 to 1; working image can be enlarged, moved, inverted, modified for clarity, brightness and contrast. dental cone-beam computed tomography method allows to detect the position, shape, sizes, construction of various structures to determine their topographic anatomic relations with other organs, and tissues. The analysis of the study results of treatment of apical periodontitis in this view doesn’t give a complete picture of the selected comparative method of treatment, which is the foundation for a thorough study of the density of tissue in the apex of the teeth in the long-term period (3-6-12 months). Experience in the use of dental computer tomography showed that it is possible to assess of the areas of destructive changes of the periapical region and periodontal tissues in most cases than traditional x-ray techniques.