1. Introduction

The working population of any country forms the basis of strategic potential through the production of gross national product. It should be emphasized that, unlike general population indicators, the health status of the working population is largely determined by various factors of labor and the labor process. Many of them include industrial aerosols and harmful chemicals, industrial noise, vibration, ionizing and non-ionizing radiation, increased severity and stress of work, unfavorable microclimate, industrial stress and a number of other factors, including behavioral ones, which are realized in the course of work. In recent years, data on the impact of dental health on the general somatic health of the patient, its interdependence with rational nutrition, household and work stresses and other risk factors are increasingly appearing. In addition, it should be noted that currently there is practically no unified system for providing medical dental care to the working population in our country, although its elements are formally regulated at the federal level. Thus, there is a high social significance of labor potential in the general structure of the country's population, unsatisfactory indicators of dental health of the able-bodied population, the presence of causal relationships between indicators of dental and somatic health of the adult population and factors of the labor process, as well as the lack of an optimally functioning system of dental care for workers engaged in harmful working conditions, including a small number of jobs Studies devoted to this problem have led to the conduct of this study [1,3,5,7,9,11].

There are publications in the available scientific literature that indicate that the topic of this study has been studied. However, we have not found any works that would aim at a comparative analysis of the impact on the dental health of the working population of the most common harmful industrial factors: industrial aerosols, a warming microclimate, increased severity and intensity of work while simultaneously exposed to a complex of endogenous and exogenous risk factors.

It is obvious that the basis of any country's strategic potential is formed by the working population, which ensures the overall receipt of gross national product. Accordingly, it is the health of the working population that will largely determine the level of national security in the near and medium term. One of the main positions in the structure of the general morbidity of the population is 20-25%, and the number of requests for dental care ranks second after the number of requests to internists. According to current data, the dental morbidity of the population aged 35-44 years is characterized by the following indicators: the prevalence of caries is 99%; KPU=14.3; the average number of preserved teeth is 22.78±0.40; the number of people with more than 20 functioning teeth is 45.56% (WHO criterion is 90%); 50.37% have dentures Moreover, in every second (50.03%) they are defective. The frequency of periodontal diseases in the adult population reaches 90%, which, along with the progressive course and insufficient effectiveness of treatment, puts chronic generalized periodontitis (CGP) among the most urgent and significant medical problems of the modern period of society development. Periodontal diseases and, above all, CGP are the main cause of tooth loss worldwide and occupy a special place among dental diseases. They are characterized by a long-term recurrent course, the presence of clinical forms that lead to the destruction of the dental system and affect the reactivity of the entire organism. According to WHO, about 95% of the adult population and 80% of children have some form of periodontal disease. The widespread prevalence and intensity of this disease in all age groups of the population has acquired not only medical but also social significance in modern dentistry. Most authors note that periodontal diseases are more common in the male population. As a rule, this is associated with an insufficiently responsible attitude of men towards their health, as well as with the more common smoking habit among them. At the same time, literature data show that among patients who seek dental care and have periodontal disease, women account for 78.7% of cases. At the same time, despite the active development of dental services at the present stage, the number of people in need of periodontal care is not decreasing and, according to various sources, averages at least 70.0%, and in some regions of the country, for example, in the Stavropol Territory, among people aged 35-44, it reaches 85%, which is evidence of an unrelenting trend towards increased activity of factors contributing to the formation of dental pathology [2,4,6,8,10].

In recent years, work has been increasingly carried out to study the impact of adverse production factors on the dental health of employees of various enterprises. Epidemiological dental examinations conducted by the authors to study the prevalence of dental pathology among workers in various industries associated with dangerous and harmful working conditions deserve special attention. He studied the combined effects of industrial factors on the organs and tissues of the mouth of workers in the main professions of industrial heating boilers. Among the complex of factors determining working conditions in the main professions of this industry, the heating microclimate, noise, vibration, as well as harmful substances polluting the air of the work area are of leading importance. The company's employees have an increase in the threshold of electrical excitability of the pulp of intact teeth, a decrease in tactile, pain, and temperature sensitivity of the gums and taste perception of the tongue, and a decrease in salivation. Ca, Mg, Fe, Cu, Mn, Zn, Ni, Cd, as well as selenium (Se), arsenic (As), lead (Pb), chromium (Cr), and mercury (Hg) were detected in hair samples. In accordance with this goal, we examined 48 people aged 22 to 50 years, including 31 women and 17 men, with a diagnosis of chronic generalized periodontitis and 125 people (80 women and 45 men) of the same age range who do not have periodontal pathology. The analysis of the interdependence between the indicators of elemental balance and the periodontal condition allowed us to propose the ratio of calcium to magnesium (K=Ca/Mg) as a predictive coefficient of predisposition to the development of CGP and an additional assessment of its severity, for which a patent was obtained. Subsequent testing of the coefficient confirmed its informative value, which allowed it to be used as an additional survey method. At the same time, the Ca/Mg ratio of 4.7 was taken as the minimum value of the cadmium content in the oral fluid (Cd0.1 mg/l); with Ca/Mg 4.7, cadmium accumulation in saliva and a predisposition to the development of CGP were predicted, and with Ca/Mg 8.4, elevated cadmium levels (more than 0.61±0.12 mg/l) and clinically pronounced CGP were diagnosed. The medical and economic analysis of dental care for employees of the studied groups was carried out on the basis of the indicators of caries intensity actually obtained in the course of work, as well as the prevalence of gingivitis and periodontitis of mild, moderate and severe degrees.

When calculating the economic damage, the indicators of unproduced products and payments due to temporary disability were used and calculated according to the formula (5): Uzvut (rubles) = (Dpr + Pbl) Tlvut, where (5) Dpr is the cost of products produced per employee per working day in rubles; Pbl is the average daily amount of temporary disability allowance for one employee in rubles; the duration of one case of temporary disability for major dental diseases. To compare the medians of the indicators in different patient groups, a nonparametric method was used to verify the equality of the medians - the Mann-Whitney U-test. The "moving average" method was used to illustrate the nature of the interdependencies of the indicators. In the process of mathematical analysis, all persons in the analyzed group were divided into two subgroups, characterized by the most and least favorable indicators of dental and somatic status. Individuals with intermediate (average) indicators were excluded from mathematical analysis, as being in the center of the distributions, they contribute to the "blurring" of differences. The level of calcium in the blood is a physiological constant maintained by balancing the processes of calcium absorption in the intestine, filtration and reabsorption in the kidneys, deposition and "leaching" from bones. The reasons for the low calcium content in the body are reduced to low intake of it from food and may be associated with a number of diseases (thyroid gland, kidneys, gastrointestinal tract), as well as with excessive intake of antagonistic elements: phosphorus, cadmium, lead, zinc, magnesium and others. Multiple correlation analysis also revealed the presence of interdependencies between the indicators of the immune status of the mouth and the content of various elements in the oral fluid, both essential and toxic. In particular, an analysis of the zinc content in the oral fluid of patients with CGP showed that with a decrease in its amount, workers with CGP experience deviations from the norm of total immunoglobulin A in the oral fluid. Thus, the zinc content in the oral fluid of patients with CGP with normal sIgA values averages 0.16±0.06 mg/l, with sIgA deviation from normal fluctuations it increases to 0.34±0.10 mg/l, i.e. almost twofold, and a direct correlation of average strength was revealed between these series of indicators (r=0.47; p=0.04). We believe that the increase in zinc content in the oral fluid with changes in sIgA concentration is related to its functional features, since the highest concentrations of zinc are characteristic of mononuclear cells and macrophages, and it is these cells that participate in the synthesis of a significant intracellular pool of metallothionein proteins and macrophages during inflammation.

In individuals with CGP, a statistically significant decrease in copper content was found from 0.68±0.04 mg/l with normal levels of immunoglobulin A in the oral fluid, to 0.26±0.03 mg/l with its deviations from the norm (p 0.001). Copper is also necessary for human life, as it is a part of many important enzymes, vitamins, hormones, participates in metabolic processes, is of great importance for maintaining the normal structure of bone tissue, elasticity of the walls of blood vessels, and is part of the myelin sheaths of nerves. The cadmium content in the oral fluid of the examined workers who come into contact with various aerosols during work, with an IdA concentration within the normal range (0.69 - 0.97 mg/l), averages 0.20±0.08 mg/l, and the IgA concentration changes both upward and downward against the background of an increase in cadmium levels (0.56±0.17 and 0.68±0.27 mg/l, respectively; p 0.01), which is confirmed by clinical manifestations in the mouth. The accumulation of cadmium in the oral fluid is also accompanied by an increase in the concentration of secretory immunoglobulin A (sIdA). Thus, in patients with a cadmium content in the oral fluid of 0.25±0.09 mg/l, SI is determined within normal fluctuations. With a twofold increase in the concentration of cadmium in the oral fluid, in all cases, there is a deviation of the SI value from the norm (0.58±0.10 mg/l, p 0.05). Cadmium is known to be a pollutant with a potential immunotoxic effect and significantly suppresses the cytolytic activity of immune macrophages. The revealed dependence is consistent with the ability of cadmium to participate in free radical oxidation processes and act as an antagonist of zinc and selenium. Inflammatory processes in periodontitis occur against the background of increased activation of polymorphoactive oxygen species, which are involved in tissue destruction, damaging DNA, causing lipid peroxidation and stimulating pro-inflammatory cytokines. Unlike essential elements, cadmium is a toxicant with a high ability to accumulate in tissues and organs. With the food intake route, only 4-5% of the administered dose is absorbed, and the rest is excreted in the faeces. The absorption of cadmium from the digestive tract is higher in women than in men. In contrast to the digestive tract, most of the inhaled, i.e. atmospheric cadmium is absorbed. Inhalation is the main route of cadmium entry into the body of smokers, as well as people living in a cadmium-contaminated area.

2. Conclusions

The analysis revealed a direct, close to statistically significant (p=0.20) trend of dependence of the severity of CGP on the content of cadmium in the oral cavity. A comparative analysis also revealed a direct correlation between changes in mercury content and fluctuations in the concentration of IgA in the oral fluid. Thus, fluctuations in IgA within the normal range correspond to the content of Hg in the oral fluid (on average 0.23±0.10 mg/l); with an increase in IgA concentration, the mercury content increases to 1.6±0.8 mg/l; a decrease in IgA is accompanied by an increase in mercury concentration to an average of 0.65±0.30 mg/l (p=0.001, p 0.05).