Wound defects of the oral mucosa are a common pathology the treatment of which often involves synthetic membranes. Development of varieties of such membranes is an ongoing process. This study aimed to register morphological features of the oral mucosa regeneration process in the presence of one of the varieties, the polymer piezoelectric membranes. The study involved 45 Wistar rats divided into 3 groups: 1) animals with an open wound defect; 2) animals with a wound defect covered with a copper-coated polymer membrane; 3) intact animals. The samples for morphometric study were collected on the 3^rd, 7^th and 12^th days. On the 3^rd day, rats of group 1 had the specific area of granulation tissue 1.4 times greater than that in group 2 (p = 0.033). In group 1 rats, endotheliocytes expressed more VEGF than in the animals of group 2. In group 2, the defect was ultimately completely covered with the epithelial layer, which was not the case in group 1. On the 7^th day, the epithelium in rats of group 2 was twice as thick as the layer registered in group 1 (p = 0.019). Granulation tissue was replaced by loose fibrous connective tissue. In group 1, the specific area of inflammatory infiltration was greater than that of loose fibrous connective tissue, and the VEGF expression level was lower than in group 2. On the 12^th day, the predominant tissue in group 2 was the loose fibrous connective tissue, the VEGF expression level equaled that of group 3, and peripheral nerves began to grow. In group 1, the specific area of dense fibrous tissue was 3.9 times greater than that in group 2 (p = 0.012), the epithelium had pathological changes and the VEGF expression was below control values. Thus, a polymer piezoelectric membrane had a positive effect on the post-wound restoration of the oral mucosa tissues.