X-ray and anatomical features of the lower jaw alveolar cortical layer in children.

INTRODUCTION: the world studies showed the interest in measurement of the buccal or anterior cortical plate thickness. Data indicate a significant superiority of the spongy substance over the compact one in the distal part of the jaw, which makes it possible to think about a higher effectiveness of transcortical injections. The empirical "rule of 10″ provides for the choice of a method of anesthesia in children for primary teeth but demonstrates difficulties with high-quality anesthesia accompanied for permanent teeth. Therefore, the importance of clinical examination and anatomical investigation of the jaw cortical plate in children for competent planning of transcortical interventions has been determined. AIM: To study the features of the clinical and X-ray anatomy of the cortical layer in distal alveolar part of the mandible in children. MATERIAL AND METHODS: The assessment of the X-ray anatomical characteristics of the mandible was carried out according to 150 anonymized cone-beam computed tomograms of patients aged 6-12 years, performed for the treatment of major diseases. Qualitative assessment and examination of the cortical plate of the distal alveolar part of the mandible were carried out on the skeletonized certified preparations of aged 6-12 in the amount of 50. RESULTS: The age characteristics of the cortical plate in the area of the chewing group of teeth in the mandible were determined according to macro anatomical studies, which confirms with the X-ray results. Therefore, the obtained images serve as actual confirmation of X-ray studies, which are ranked by age. The thickness of the cortical plate in the second primary molar of the mandible in subgroups 6, 7 and 8 years has a proportional increase from the cervical region to the apical projection. The average thickness of the cortical plate is 1.57 mm at 6 years, 1.52 mm at 7 years, 1.6 mm at 8 years and 1.84 at 9 years. The cortical plate thickness in the first primary molar of the mandible in subgroups 6 and 7 years has a proportional decrease from the cervical region to the apical projection as well as an inverse proportion to age. The average thickness of the cortical plate is 1.33 mm. In the first molar of the mandible at the age limit of 6-12 years the attention is drawn to the linear increase in tissue volume from the cervical region to the apical projection up to 8 years. At 6-8 years the average thickness of the cortical plate in this age group is 1.74 ± 0.2 mm, at 9 years - 2.03 mm, at 10 - average value in the cervical region it is 1.53 ± 0.23 mm, in the root middle it is 2.19 ± 0.13 mm and in the apical projection it is 1.98 ± 0.16 mm, at 11-2.22 mm and at 12-2.35 mm. For the second primary molar the average thickness of the buccal cortical plate of the second primary molar is 1.4 mm in cervical part, 1.68 mm in the root middle and 1.81 mm in the apical projection. Finally, thickness of the buccal cortical plate in the cervical region of the first permanent molar is 2 mm in groups. CONCLUSION: The study makes it possible to determinate with noninvasive way the age limit for the least pronounced zone of the buccal cortical plate.

COVID-19 Vaccinating Russian Medical Students-Challenges and Solutions: A Cross-Sectional Study.

Background: The role of preventive measures increases significantly in the absence of effective specific COVID-19 treatment. Mass population immunization and the achievement of collective immunity are of particular importance. The future development of public attitudes towards SARS-CoV-2 immunization depends significantly on medical students, as future physicians. Therefore, it seemed relevant to determine the percentage of COVID-19-vaccinated medical students and to identify the factors significantly affecting this indicator. Methods: A total of 2890 medical students from years one to six, studying at nine leading Russian medical universities, participated in an anonymous sociological survey. The study was performed in accordance with the STROBE guidelines. Results: It was found that the percentage of vaccinated Russian medical students at the beginning of the academic year 2021 was 58.8 ± 7.69%, which did not significantly differ from the vaccination coverage of the general population in the corresponding regions (54.19 ± 4.83%). Student vaccination rate was largely determined by the region-specific epidemiological situation. The level of student vaccination coverage did not depend on the gender or student residence (in a family or in a university dormitory). The group of senior students had a higher number of COVID-19 vaccine completers than the group of junior students. The lack of reliable information about COVID-19 vaccines had a pronounced negative impact on the SARS-CoV-2 immunization process. Significant information sources influencing student attitudes toward vaccination included medical professionals, medical universities, academic conferences, and manuscripts, which at that time provided the least information. Conclusion: The obtained results make it possible to develop recommendations to promote SARS-CoV-2 immunoprophylaxis among students and the general population and to increase collective immunity.

Construction of Customized Palatal Orthodontic Devices on Skeletal Anchorage Using Biomechanical Modeling.

Orthodontic implants have been developed for the implementation of skeletal anchorage and are effectively used in the design of individual orthodontic devices. However, despite a significant amount of clinical research, the biomechanical aspects of the use of skeletal anchorage have not been adequately studied. The aim of this work was to numerically investigate the stress-strain state of the developed palatal orthodontic device supported by mini-implants. Four possible options for the placement of mini-implants in the bone were analyzed. The effect of a chewing load of 100 N on the bite plane was investigated. The study was carried out using biomechanical modeling based on the finite element method. The installation of the palatal orthodontic device fixed on mini-implants with an individual bite plane positioned on was simulated. The dependence of equivalent stresses and deformation changes on the number and location of the supporting mini-implants of the palatal orthodontic device was investigated. Two materials (titanium alloy and stainless steel) of the palatal orthodontic device were also investigated. The choice of a successful treatment option was based on the developed biomechanical criteria for assessing the surgical treatment success. Application of the criteria made it possible to estimate the stability and strength of fixation of each of the considered mini-implants installation options. As a result, options for the mini-implants optimal placement were identified (the first and the fourth which provide distributed front and side support of the device), as well as the preferred material (titanium alloy) for the manufacture of the palatal orthodontic device.

Determination of sex dimorphisms of the thickness of the hard palate in adolescence using computed tomography: Pilot study.

BACKGROUND: In addition to traditional craniometric techniques, computer craniometry has been used in recent decades, including stereometric methods, which make it possible to determine the microanatomical spatial relationships and dimensional features of various structures of the skull, in particular the thickness of the inert palate of the maxilla. AIM: Determination of the gender-specific variability of the thickness of the bony palate at the age of 18-20 years using CT. MATERIAL AND METHODS: The material of the pilot study were 40 computed tomograms of young males and females aged 18-20 years. The method of computer craniometry was used to measure the thickness of the bony palate in sagittal projection taking into account the gender. A graphic raster map was created to identify the palatal areas, then analyze their thickness and determine the safe zones for the mini dental implants. RESULTS: In young males and females (18-20 years) the thickness of the bony palate decreases at different levels from front to back and from the median suture to the alveolar process. The greatest thickness of the bony palate corresponds to its anterior third and reliably predominates in young males at all levels compared to young females. In the middle and posterior third palate, the averages do not show gender differences and their variation is insignificant. CONCLUSIONS: The greatest thickness of the bony palate can be used as the most favorable zone for the fixation of orthodontic mini dental implants. The variability in the thickness of the bony palate should be considered when selecting the most optimal zones and depth of mini-implant placement.