Медицина./ Морфология

Yuldashev A.A.

Department of Pediatric dentistry, Tashkent medical academy, Uzbekistan

BONE RECONSTRUCTION OF ALVEOLAR RIDGE OF UPPER JAW IN ANIMALS: EXPERIMENTAL STUDY

Purpose of the research: To study morphological changes in the regeneration process in a zone of defect of the upper jaw of animals when using autogenous bone graft and umbilical cord.

Material and methods. The umbilical amnion is a membrane consisting of a gentle network of fibers; it is outside covered with the amnionic shell represented by an ectodermal amnionic epithelium. The existence of the undifferentiated cells leads to the transformation of an amnionic epithelium in cells of the operated area.

In the experiment made by us 14 non-thoroughbred rabbits were used at the age of 3-4 months with an average weight of 2,0-2,5 kg. In all the animals standard osteal defects were reproduced in the field of the alveolar process of the upper jaw. The membrane was fixed without a seam; it was covered with mucous and periosteal flaps. Then mucous and periosteal flaps stacked in place and took in polyglycolide seams.

Results: The results of the microscopic research showed that, on the 14th day of the experiment it becomes perceptible that the differentiation of the preliminary connective-tissue callosity into a preliminary osteal callus occurs gradually and begins on the side of the periosteal surface of the osteal defect and the autogenous bone. On the 21st day of the experiment it was revealed that, on the part of the preliminary osteal callus, there is a thickening of fascicles of the coarse-fibered osteoid, an accumulation of exhaust in them, and an emergence of additional beams between fascicles. Later, between the separate beams forming the primary system of bone regenerators, there appear transversal intersections. On the 30th day of the experiment, full attachment of the cord and the periosteum to the external surface of the autogenous bone graft became perceptible.

Conclusion: The formation of the final osteal tissue from the coarse-fibered spongiform osteal callus takes place through the massive resorption of chaotic soft old structures by the osteoclasts and their replacement by new structures ordered with the formation of haversian channels, which are filled with vessels and a soft cellular-fibrous tissue, or so-called fibrous marrow. During the reparative regeneration the cord is exposed to a loosening, a resorption and merge to the surrounding neogenic connective-tissue callosity formed by the periosteum.