The epidemiological aspects of endodontics in comparison with the epidemiology of caries have been insufficiently studied, especially in our country. Aim. The purpose of this work is to assess the endodontic status of patients depending on the level of dental caries resistance. Material and methods. We, based on clinical observations, put forward an assumption about the relationship between the frequency and nature of complications of caries and the level of their resistance to disease according to Nedosenko V.B. The subject of our study was to test this assumption on factual material. The materials of the study were medical documents of 292 patients treated for diseases of the periapical tissues. Orthopantomograms of these patients were analyzed. Methods of statistical analysis were used for assessments and conclusions: Kullback's information statistics and the difference method. Results. When considering the relationship between complications of caries and levels of resistance, an inverse relationship was found, that is, among persons with an average level of dental resistance to caries, the frequency of complicated forms is much lower than among persons with low and very low (p < 0.001). Most often, diseases of the periapical tissues with a destructive process in the periodontium occurred in persons with a low level of resistance. The frequency of diagnostics of destructive periodontitis arising without endodontic treatment and periodontitis arising after endodontic treatment in patients with an average level of resistance is lower than in patients with a low level of resistance. Discussions. The lower the level of resistance of teeth to caries, the more often untreated periodontitis is detected, more often destructive periodontitis occurs as an outcome of endodontic treatment for pulpitis. Conclusions. The data we have obtained allow us to increase the effectiveness of caries treatment, taking into account the level of tooth resistance.