THE INCIDENCE OF SPORTS INJURIES AMONG SCHOOL-AGED CHILDREN AND ADOLESCENTS.

It is estimated that approximately one in ten school-aged children experience sports-related injuries annually. These injuries are most common at 12 years of age. Boys are more likely to get injured and more likely to get seriously injured than girls. The probability of injury is greater in contact or high-impact sports, with American soccer accounting for the largest number of injuries, followed by wrestling, basketball, soccer, and baseball. In certain sports, such as horseback riding, women are four times more likely to sustain injuries. The presented literature review details the incidence of various sports-related injuries in adolescents. Sports-related injuries observed in children under the age of 10 are nonspecific and include contusions, mild sprains, and fractures of the extremities, most commonly Salter-Harris fractures (growth plate fractures) or plastic fractures. In young athletes, sports-related injuries of the ligaments or muscles, as well as spinal or head injuries, are rare. This is particularly true during puberty, where growth plate fractures and musculoskeletal injuries occur more frequently.

EFFECT OF SURFACE TREATMENT PROTOCOLS OF ZIRCONIUM DIOXIDE MULTILAYER RESTORATIONS ON FUNCTIONAL PROPERTIES OF THE HUMAN ORAL MUCOSA STROMAL CELLS.

Aim - to study the effect of protocols of surface treatment of zirconium dioxide multilayer restorations on the functional properties of stromal cells of the human oral mucosa using molecular biological methods. For all experiments, identical standardized specimens of different types of zirconia with a diameter of 10 mm and a height of 1 mm were used. These types included Katana (Kuraray Noritake Dental, Tokyo, Japan) HTML (control) UTML, STML and ZirCAD Prime (Ivoclar Vivadent). DMEM/F12 growth medium (Paneco, Russian Federation) with addition of fetal calf serum (Gibco, USA) up to 10% and penicillin-streptomycin (Paneco, Russian Federation) up to 1% was used in the experiment. Cells were detached from the culture substrate with trypsin-EDTA solution (Paneco, RF) and their number and viability were assessed using an automatic counter TC-20 (Bio-Rad, USA). For repopulation, samples were transferred into wells of a 96-well culture plate (1 sample in 1 well) and cell suspension was layered at the rate of 12.5 thousand or 25 thousand live cells per well. After 48 hours, the cytotoxic properties of the tested samples were evaluated in vitro. According to the results of MTT test we can conclude that samples of ZirCad Prime and Katana UTML groups do not show cytotoxic properties (score "0" on the cytotoxicity scale according to GOST R ISO 10993-5-2009 "National Standard of the Russian Federation. Medical devices. Evaluation of biological effect of medical devices. Part 5. Studies on cytotoxicity: in vitro methods"). The samples of Katana STML group samples were slightly reduced compared to the control (about 12%), nevertheless, these samples can also be considered non-cytotoxic. Analyzing the direct contact with the material in all samples, a good occupancy of the material by cells was observed, in particular, the polished surface prevailed over the glazed one, however, this difference is not statistically significant. Analysis of human oral stromal cells to zirconium dioxide showed no statistically significant effect of different surface treatment protocols. However, the number of fibroblasts prevailed on the polished surface.

СOMPARATIVE SPECTROPHOTOMETRY ANALYSIS OF ZIRCONIUM DIOXIDE WITH THE CUBIC AND TETRAGONAL PHASE AFTER ARTIFICIAL AGING.

Aim - to evaluate optical features of the 3, 4 and 5Y-TZP zirconium dioxide with the spectrophotometry analysis under artificial aging procedure. For all experiments, identical standardized specimens of different types of zirconia with a diameter of 10 mm and a height of 1 mm were used. These types included Katana (Kuraray Noritake Dental, Tokyo, Japan) HTML (control) UTML, STML and ZirCAD Prime (Ivoclar Vivadent). Artificial aging (low-temperature degradation) was performed using the following autoclaving regime: 134 degrees Celsius, 2 atmospheres, 5 hours. A Shimadzu UV-3600 spectrophotometer was used to study the spectral characteristics of the provided samples. Since the samples have low bandwidth, it was decided to investigate the reflectance spectra. For this purpose, a Shimadzu SR-1503 integrating sphere was installed on the spectrophotometer. Results: All samples of Prime manufacturer show an increase in the reflected signal intensity in the range of 650-820 nm. This range corresponds to red and orange colors, which means that as a result of autoclaving the beige tint of the materials will become more pronounced. The intensity of scattered light of the sample UTML-glaze and STML-glaze has lower values in the whole visible wavelength range. However, the intensity decrease in this case is not uniform. In the range above 500nm the intensity decrease is more pronounced, which means that as a result of artificial aging the beige tint of the materials will become somewhat less pronounced. Zirconia restorations with a predominantly tetragonal phase with polished and glazed surfaces will not change reflectance during artificial aging.