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The method of light microscopy was used to study the reactions of the surrounding tissues to the implantation of non-degradable surgical materials (prolene 3/0 thread made from polypropelene, the composite grid made from polypropelene or polyester with polylactic acid) in the subcutaneous adipose tissue of rats 1, 2, 6 and 12 months after grafting. No less than 6 rats were examined in every time point. It was shown that the tissue reactions to implantation of different non-degradable surgical materials follows the general pattern, characteristic of wound process and foreign body reaction. By the first month of observation in both groups of animals the stage of traumatic perifocal inflammation was replaced by the proliferative phase with the formation of new blood vessel and connective tissue. The tendency to reduction of the activity of productive inflammation was observed from the 1st to the 12th month together with the increased fibrous scar transformation of the granulation tissue.

The reaction of rat tissues to intraperitoneal placement of implants made out of biodegradable polyhydroxyalkanoates (PHA), was studied at different time points after the operation by the methods of light microscopy. It was found that after intraperitoneal PHA implant placement, the active adhesive process started leading to formation of fibrous adhesions between PHA implants and intestinal loops. When PHA implants were used in the form of films, they became surrounded by a thick fibrous capsule. As a result of PHA implant placement in the form of ultrathin fibers, the extensive foreign body granulomas with perifocal inflammation and sclerosis of surrounding tissues were formed. In these granulomas the polymer fragmentation and phagocytosis by macrophages with formation of giant cells of foreign body occured. It is concluded that PHA implants are not biodegradable and induce tissue reactions similar to those caused by other foreign bodies.

Tissue reactions to titanium-nickelide and polypropylen and caprone implants used in surgical treatment of anterior aldomen wall hernias were studied in experiment. Digital density of leukocytes, fibroblasts, vessels, thickness of the capsule were studied. Pronounced inflammatory reaction was observed on day 3 which attenuated on day 14 in case of titanium nickelide and on day 30-60 in case of polypropylene and caprone. Fibroplastic processes start in the first group after 7 days while in the second group only after 30 days of the experiment. Thickness of the capsule around titanium-nickelide was 2-3 times less than around polypropylene and caprone. Thus, titanium-nickelide material is biologically more inert than caprone and polypropylen which are widely used in surgery of hernias.

Self-hardening material for metal plastic permanent dentures, has been developed by the Central Research Institute of Dentistry for the first time in Russia. Its physicomechanical properties are described and the results of toxicological trials are presented. The new material is superior in wear resistance to foreign analogs Kulzer Dentacolor and ESPE Visio-Gem. Toxicological studies demonstrated the biological inertness of the material during long contact with the internal media of human organism and the absence of toxic, sensitizing, and mutagenic action.