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 spongy substance, and in the group with complete loss of teeth, the third type, in which the spongy layer is loose a network of thin trabeculae It was found that with tooth loss, the ratio of compact and spongy substances changes due to an increase in the amount of the latter, violation of the integrity of the dentition is accompanied byincrease of trabecular thickness by 8.7% as compared with the group with intact bite, which may be one of the predisposing the development dysfunction of the temporomandibular joint in patients with partial or complete tooth loss.