Prevention and treatment of dental hard tissue pathologies in patients exposed to combined and radiation treatment of oral cavity and pharyngeal malignancies are an urgent and challenging issue for the clinical dentistry. Deterioration of tooth enamel after radiation is similar to caries in the spot stage, which allows using infiltration of tooth enamel. Aim of the study: to identify the effectiveness of enamel infiltration with Icon in patients subjected to radiation therapy for the oral cavity cancer. Materials and methods: enamel infiltration was performed for the vestibular and proximal surfaces of 35 teeth in patients who received radiation therapy for oral cancer (squamous cell tongue carcinoma, squamous cell amygdala carcinoma). The study outcomes were evaluated 6 months, 1 year and 1.5 years following the treatment. Results and discussion: enamel gloss was recovered in 32 teeth; chalky spots disappeared completely in 28 cases, while another 7 cases featured significantly decreased severity. In total, the progression of the carious process was to be observed in 14.3% of the cases within 1.5 years, mainly on the proximal surfaces of the teeth. Conclusion: enamel infiltration with Icon is an effective treatment for enamel demineralization in patients who underwent radiation therapy. K E y w o r d s-radiation caries, enamel infiltration method.