The objective of the experiment is to investigate the morphological structure of dental tissues in people of different age groups suffering from tissue hyperesthesia. Materials and methods. The morphological structure was studied by scanning electron microscopy. We studied 57 teeth that had been removed for medical reasons in 45 adults. With the help of microscopy, hard tissues (enamel, dentin and cement) of teeth were studied. The study involved intact and pathologically altered teeth. Intact teeth were removed for orthodontic indications. In older people, removal was performed due to exacerbation of chronic periodontitis and periodontitis. Results. The revealed morphological changes in dentin are due to the main pathology: whether hyperesthesia is associated with the loss of tooth hard tissues or developed without it. Non-carious lesions of hard dental tissues (erosion and wedge-shaped defects) during morphological examination are caused by a violation of the integrity of the cement, cracks and chips of enamel. It was found that in patients the increased tooth sensitivity and morphological changes develop due to the presence of carious and non-carious processes in the dentin and are independent of gender and age. Conclusion. Both in the carious process and in non-carious lesions of the teeth, no relationship was established between the severity of hyperesthesia of the teeth and the degree of obliteration of the dentinal tubules.