Vol 26, No 3 (2023): Опубликован 27.09.2023

Improving the technology of dental prosthetics, especially those based on dental implants, is closely related to the development and research of structural materials. The article provides data on a comparative study of the physical and mechanical properties of polyetheretherketone as a material for the manufacture of removable dentures supported by dental implants. Data on indicators of bending strength, diametric tensile strength and coefficient of friction for steel were studied. An experiment to study the retention capacity of a telescopic fixation system for removable dentures is described and the data obtained are analyzed.

Despite the rapid development of orthopedic dentistry and the release of a large number of materials used to fix fixed structures, it is impossible to single out among them an ideal one for every case. There are several classes with significantly different characteristics. Even representatives of the same group have significant differences in properties, which is associated with continuous work on the recipe to adapt to modern requirements.

Every orthopedic dentist tries to choose for himself a material that satisfies all parameters, used in dental practice as a fixing fixed structures. He pays special attention not only to the convenience of working with cements or their physico-chemical, physico-mechanical properties, but also to its bioinertness and biocompatibility.

To assess the effect of fixing materials on surrounding tissues, a comparative assessment was carried out with the measurement of the toxicity index of materials and the papillary-marginal-alveolar index (PMA).

Vitamin D deficiency is a widespread problem among carriers, people living in acute lack of sunlight in northern latitude regions, this is the result of low serum concentrations of the vitamin. Chronic lip fissure and meteorological cheilitis are the most common forms of cheilitis among residents of the Far North. The role of vitamin D deficiency has not been studied in patients with these diagnoses. The purpose of the study is to measure the level of vitamin D in the blood serum in patients with chronic lip fissure and meteorological cheilitis, as well as to dynamically study the dependence cases of disease recurrence on the concentration vitamin D. The study was conducted in 79 residents of the Murmansk region for 12 months. Diagnostic results have established that low serum vitamin D concentrations support the recurrence of meteorological cheilitis and chronic cleft lip. The use of vitamin D to maintain a normal level of vitamin in the blood serum improves the regenerative ability of the lip skin, maintains the barrier function of the epithelium, and reduces cheilitis recurrence rate. The study found that in the conditions of the Far North one of the mandatory components of the prevention and pathogenetic therapy of meteorological cheilitis and chronic lip fissure should be vitamin therapy with cholecalciferol preparations.

The issues of the complexity of diagnosing diseases of the pulpoperiodontal complex of teeth of patients who had previously recovered from COVID-19, as well as the need to select the most adapted algorithm for the treatment of pathology, depending on the clinical manifestations in the oral cavity, were studied. An increase in the activity of opportunistic microorganisms, which normally do not show activity in the oral cavity, gives rise to the development of various pathologies of hard tissues of the teeth, the pulp and periodontium. The expediency and necessity of including in this category of patients, in addition to the standard dental examination, also additional examination methods (for example, blood test, bacterioscopy, bacteriological tests, testing of the microvasculature, and others) before the start of any dental treatment. Emphasis is placed on the elimination of a certain type of microorganism, identified with the help of additional examination methods, thereby preventing the occurrence of long-term complications after endodontic treatment of the tooth.

Relevance. Among the variety of reasons for unsatisfactory results of treatment of patients with artificial crowns and their premature removal or cementation, the researchers highlight the development of secondary caries. One of the significant reasons for its occurrence is the quality of the marginal fit of artificial crowns.

The goal is to perform a laboratory assessment of the thickness of the cement film in the area of ​ ​ the edge of the artificial crown and establish the degree of its influence on the probability of the development of the carious process.

Procedure. Splints of 50 freshly removed teeth covered with artificial crowns were made, on which the thickness of the cement film was measured, and the presence of caries at the edge of the artificial crown was determined.

Results. The development of caries under the artificial crown is typical of teeth dissected with a ledge. The threshold value of the thickness of the cement film, above which caries more often developed in the studied sample of teeth, was 115-120 microns. The probability of unacceptable thickness of the cement film and the development of caries in teeth prepared with a shoulder is 6.6 times higher than in preparation without a shoulder.

This article highlights the peculiarities of the influence of the dominant hemisphere on the effectiveness of orthopedic dental manipulations. Left-hemisphere and right-hemisphere students dissected the first molar of the lower jaw for a metal-ceramic crown with different hands. The effectiveness of the students' work was evaluated according to the criteria of time spent on preparation (A), thickness of grinding from the occlusal (B) and contact surfaces of the tooth (C), convergence angle (D), and the width of the formed ledge (E). According to the results of the study, it became known that right-hemispheric students working with the right hand showed abnormal results: the A indicator was 16.7 minutes; B - 1.6 mm; C - 1.7 mm; D - 22˚; E - 1.9 mm. The results of these students, revealed when working with the leading hand, correspond to normal parameters: indicator A - 14.5 min; B - 1.7 mm; C - 1.3 mm; D - 14˚; E - 1.2 mm. Left hemispheric students working with the right hand also showed results within the normal range: indicator A - 14.4 min; B - 1.8 mm; C - 1.3 mm; D - 12˚; E - 1.1 mm. The conducted research indicates the need to pay increased attention to the training of left-handed students and to provide this group of students with special educational equipment.

The change in the adrenoreactive properties of membrane and cellular structures under the influence of catecholamines makes it possible to consider the beta-adrenergic reactivity of the erythrocyte membrane (β-ARM) as a systemic indicator of the organism's adrenoreactivity. To assess adrenoreactivity, a technique is used based on a quantitative assessment of the degree of inhibition of hypoosmotic hemolysis of erythrocytes in vitro in the presence of the beta-blocker propranolol. The article presents data on the comparison of spectrophoto- and colorimetric determination of erythrocyte membrane beta-adrenoreactivity based on the registration of erythrocyte hemolysis with digital signal processing. A smartphone was used to register the images of the analyzed samples. Photography was carried out in a special box under standard lighting conditions. The chromaticity of the obtained images was evaluated using the Photoshop program within the RGB color model intended for computer color rendering. The obtained RGB values were used for quantitative determinations. The study was performed on 20 blood samples of patients suffering from bronchial asthma. The discrepancy between the results of determining β-ARM using the colorimetric and spetrophotometric methods was no more than 5.6%, which indicates the possibility of replacing the spectrophotometer with image registration in digital format using software.