Рентгенометричне дослідження оптичної щільності кісток щурів після заповнення дефектів кісткової тканини кістковими цементами на основі трикальційфосфату.

Background. In modern orthopedics, there are many options for replacing bone defects. The attention of researchers was drawn to calcium phosphate ceramics. Studies have shown that hydroxyapatite (HA) — Ca₁₀(PO₄ )₆ (OH)₂ and tricalcium phosphate (TCP) — Ca₃ (PO₄ )₂ ceramics has a number of advantages over other biomaterials. However, it is not clear how reinforcement will affect the rate of bone formation in the implantation zone and its density. The purpose was to study the dynamics of changes in bone density in the area of a defect filled with α-TCP cements in an experiment on laboratory animals. Materials and methods. X-ray study of the optical density of the bone tissue of laboratory rats after replacing bone defects with TCP cements was carried out. Changes in the optical density of the bone tissue of rats who underwent the replacement of an artificially formed defect in the metaepiphyseal zone of the femur with α-TCP (5 animals) and α-TCP reinforced with needle-like HA crystals (5 animals) were studied. Rats underwent digital radiography of the operated and intact bones in 1, 2, and 3 months. The optical density of the cortical bone was measured in the area of implantation of the operated bone and the cortical layer of the intact femur of the metaepiphyseal zone at the same level. Results. It was found that the optical density of intact bone in animals in both groups gradually increased during the experiment. Differences in the value of the optical density of intact bones were not found (p >> 0.05). Despite the fact that at the initial stage, the replacement material based on α-TCP + HA has a higher optical density, it subsequently degrades and is replaced by bone tissue the optical density of which approaches the level of intact bone. The studies conducted have shown that one month after the replacement of a bone defect, a higher tissue density in the defect zone is observed if it is filled with α-TCP + HA bone cement that is most likely due to a higher density of the material itself compared to cement containing only α-TCP. Two months after filling a defect, there is an alignment of the bone density in the defect zone with the density of intact bone, which suggests that the process of replacing the artificially formed defect in the metaepiphyseal zone with bone tissue has occurred. Conclusions. The optical density of intact bone in animals of both groups during the experiment gradually increased: from 90 ± 8 units to 98 ± 7 units in the group of Ca₃ PO₄ + α-TCP and from 89 ± 5 units to 100 ± 12 units in the group of Ca₃ PO₄ + α-TCP + HA, but there was no statistically significant difference in the value of the optical density of intact bones (p >> 0.05). One month after the replacement of a defect with Ca₃ PO₄ + α-TCP + GA, a statistically significantly (p = 0.017) higher optical density of the operated bone (113 ± 6 units) was noted compared to the replacement with Ca₃ PO₄ + + α-TCP (101 ± 8 units). Two months after the experiment was started, the optical density of intact and operated bones at the level of defect replacement was statistically equal in both groups, which was confirmed in 3 months as well. This may indicate the replacement of the filler with bone tissue. [ABSTRACT FROM AUTHOR]