The prevalence of allergic reactions among patients visiting an orthopedic dentistry clinic reaches 7% for acrylates, 18, 8% for metal alloys, galvanosis - 14,6% and toxico-chemical stomatitis - 8,9%. The urgency of the problem is determined by the difficulties of diagnosis and differential diagnosis of intolerance to dental construction materials. The purpose of the study: substantiation of differential diagnostic approaches in assessing the phenomena of intolerance to dental construction materials and similar clinical conditions, the creation of algorithms for the diagnosis of patients with intolerance to dental construction materials. Materials and methods. A total of 1524 patients with a preliminary diagnosis of intolerance to dental construction materials (main group) were examined. The control group consisted of 206 people with dental prosthesis in the oral cavity without complaints and intolerance phenomena. The main and additional research methods were used, including exposure and provocation tests, epicutaneous and intraoral epimucous allergological tests, measurement of impedance and galvanic current, immuno-allergological examination of patients. Results. The analysis of clinical and medical history data, as well as the development of new devices and methods for diagnosing intolerance to dental construction materials, allowed us to expand and clarify a number of indicators and data for the implementation and simplification of differential diagnosis of intolerance to dental construction materials and all other similar clinical conditions. The proposed algorithms for diagnosing intolerance to dental construction materials of an allergic nature, toxic-chemical stomatitis, galvanosis, a combination of several types of intolerance to dental construction materials streamline and simplify the interpretation of the results of basic and additional research methods. An analysis of subjective and objective characteristic manifestations in each specific clinical case allows for accurate diagnosis, to establish the etiopathogenetic links of the onset of the disease and to prescribe adequate treatment. An intraoral epimucous allergological test allows one to predict with great accuracy the body's response to dental material compared to an epicutaneous allergological test. Laboratory methods for the study of intolerance to dental construction materials are auxiliary, and the results should be interpreted only in conjunction with the data of the clinical examination of patients