Introduction. Wound healing is a process based on a complex mechanism of intercellular interaction. The aim was to study changes in the oral mucosa cellular composition during wound healing with and without a protective piezoelectric coating. Materials and methods. The study was carried out on 50 Wistar rats divided into four groups: one control group of intact rats and experimental groups 1, 2, and 3. The rats of the experimental groups were subjected to excision of a lip mucous membrane flap with wound formation. In the animals of experimental group 1, the defect was open. In group 2, we used a polymer membrane with copper modification, and in group 3, the membrane was without copper modification. The animals were sacrificed on days 3, 7, and 12 of the study. We used light and electron microscopy to study the qualitative and quantitative changes in the composition of cell populations at the site of the defect. Results. On day 3, there prevailed neutrophilic infiltration in all groups. In groups 2 and 3, we observed a large number of macrophages and fibroblasts that indicated the transition to the next phase of wound healing. On day 7, in group 1, there persisted extensive neutrophilic and macrophage infiltration, whereas, in groups 2 and 3, the signs of inflammation decreased, and wound healing was active. On day 12, in group 1, all values were significantly higher than in the control group and there was damage to the ultrastructure; in groups 2 and 3, all the studied parameters reached the control values. Conclusion. We revealed the patterns of changes in the cellular composition of a wound during its healing. The use of the coating contributed to accelerated wound healing, which was found during the analysis of changes in the composition of cell populations. The closure of the oral mucosa wounds with polymer piezoelectric membranes was proven to have a good effect on tissue repair and was supposed to reduce the risk of postoperative complications. Keywords: wound defect, mucous membrane, oral cavity, piezoelectrics, inflammation, regeneration, scaffolds, dentistry

Introduction. Restoration of blood supply to tissues is crucial for the regeneration of wound defects. The purpose of this research was to study the effect of piezoelectric polymers on the restoration of microcirculation and hemodynamics in the area of oral mucosa wound defects. Materials and methods. The study was carried out on 60 Wistar rats divided into four groups (15 rats each): control (intact) and 3 experimental groups. In group 1, the animals had an open wound defect. In groups 3 and 2, the rats had a wound defect covered with a membrane with and without copper modification, respectively. The specimens for subsequent light and electron microscopy were collected on days 3, 7, and 12. We studied qualitative and quantitative indicators of microcirculation and hemodynamics restoration. Results. Day 3: in all experimental groups, the arteriolo-venular relationship and the pericapillary diffusion index significantly decreased, while the Kernogan index increased. We also observed a significant increase in VEGF expression. Day 7: in experimental group 3, the values of the Kernogan index and the arteriolo-venular relationship were restored, and the pericapillary diffusion index remained significantly higher than in the control group. In the groups 1 and 2, none of the indicators reached the control values. VEGF expression decreased in all groups. On day 12 in group 1, the arteriolo-venular relationship, the Kernogan index and the index of pericapillary diffusion differed from the control group, in contrast to groups 2 and 3, where all the studied parameters were restored. Expression of VEGF in group 1 was significantly less than the control values, and in groups 2 and 3 it was significantly higher. Conclusion. We revealed that closing of oral mucosa wound defects by a piezoelectric polymer membrane led to the restoration of hemodynamic parameters and promoted active vascular formation. Keywords: wound defect, oral cavity, inflammation, regeneration, microcirculation, neoangiogenesis