[Autotransplantation of a horizontally oriented fragment of the root of a removed tooth to preserve alveolar tissues]. / Autotransplantatsiya gorizontal'no orientirovannogo fragmenta kornya udalennogo zuba dlya sokhraneniya tkanei al'veoly.

THE AIM OF THESTUDY: To develop a method to contain atrophy of the alveolar bone and surrounding soft tissues in the area of many cortical teeth in the first 3 months after removal for subsequent installation of a dental implant. MATERIALS AND METHODS: A description of a method for containing atrophy of the alveolar bone and surrounding soft tissues after removal of the first molar of the mandible 3 months after tooth extraction is presented. The method consists in closing the mouth of the well with a horizontally oriented fragment of the root of the removed tooth with a preserved section of the ligamentous apparatus. An X-ray assessment of bone restoration in the lumen of the well was carried out according to the Hounsfield coefficient and an assessment of the condition of soft tissues in the area of surgery 3 months after removal. For histological assessment of bone maturity, bone was taken from the implantation area 14 weeks after tooth extraction. RESULTS: The technique allowed to preserve the quality of soft tissues close to the original; on three-dimensional X-ray images in the lumen of the well, bone restoration sufficient for the installation of a dental implant is diagnosed, the zonal value of the Hounsfield coefficient is more than 300 units; histologically, a well-developed network of coarse-fibrous trabeculae is determined with the beginning of reconstruction into lamellar bone, regeneration of the alveolar process occurs by intramembranous ossification. CONCLUSION: The proposed technique contributes to the preservation of the qualities of the marginal gum in the healing zone after tooth extraction and the formation of sufficient bone maturity in the lumen of the well.

AB0 and rhesus blood groups as a risk factor for ARVI COVID-19.

The frequency of AB0 and Rhesus blood groups was studied in 12120 patients with COVID-19, 5180 convalescent plasma donors and 118801 healthy donors from Moscow, Smolensk, Yakutsk, Minsk and Gomel. In infected individuals, the frequency of blood group A was significantly higher than in uninfected individuals (41,54 % and 34,39 % respectively, p<0,05), and the frequency of blood group 0, on the contrary, was significantly lower (27,69 % and 36,71 %, p<0,05). The frequency of blood group A was particularly high among patients who died from ARVI COVID-19 - 45,51 % vs. 34,39 %, p=0,008. In some groups of patients, there was a decrease in the frequency of Rh-negative individuals (2,23 % vs. 8,30 %, p<0,001).