On 40 horizontal cuts of the head of the lower jaw, structural features of its bone tissue were studied with complete loss and complete absence of teeth on the lower jaw. The classification of bone quality we modified according to U. Lekholm and G. Zarb was used as the basis. According to it, three types of bone structure of the head of the lower jaw were identified. The first type is characterized by the presence of a relatively thick layer of compact substance and pronounced spongy substance; for the second - the presence of a thinner layer of compact substance and a spongy substance having a clearly defined fine-meshed structure, and the third type is characterized by the fact that a thin compact layer surrounds the spongy layer with a low density of trabeculae. It was established that most often in the group with a complete set of teeth there is the first type of bone structure of the head of the lower jaw, characterized by the presence of a relatively thick layer of compact substance and pronounced spong