Introduction: A thorough knowledge of the anatomy and variability of the pterygomandibular space (PMS) is essential to the success of local anesthesia. This study is aimed at determining the volume of the PMS depending on the shape of the skull, face and mandible using the computed tomography (CT).Materials and methods: anonymized computed tomograms of 48 adult patients were analyzed, the indicators of the cranial index (CI), facial index (FI) according to Yzard, the high lengthy index of the mandible (HLI), the latitudinal-altitude index of the mandible (LAI), the longitudinal latitude index of the mandible (LLI) were calculated.Results: Differences in the volume of the PMS were found depending on the shape of the skull, face and mandible. When determining the CI, the largest volume of space on the right was observed with brachycrania (2.05 ml), on the left -with mesocrania and brachycrania (2.0 ml each). With regard to the FI, the largest volume of space was obtained with medium face on the right side (2.03 ml) and broad and medium types of faces (2.0 ml each) on the left. When calculating the indicators for the shapes of mandible, the largest volume of space was found in the brachygenic (2.05 ml), leptogenic (1.98 ml) and platigenic (1.97 ml) shapes on the right and leptogenic and platigenic shapes on the left (2.0 ml each). There were statistically significant differences in the volume of the right side of the PMS between different shapes according to the cranial index (F = 5.075; p = 0.0095). The most pronounced difference was present between samples with brachycrania and dolichocrania: 0.35 mm3 (95% CI 0.05-0.65); p = 0.0188. There was a statistically significant correlation with sex for parameters on both the right and left sides. The values of indicators in men exceeded those of measurements obtained from women.Conclusion: The data obtained determine the differences in the volume of the PMS in individuals with different shapes of the skull, face and mandible, as well as sex differences. Thus, indicating the need to take into account these features when choosing the required amount of anesthetic in clinical practice. The average volume of the PMS space, according to our data, is 1.8-2.0 ml, which is consistent with the clinical data described in the literature.

Weakening of the chewing act, typical for modern humans due to consumption of soft food, causes a deficit of chewing load and has a negative effect on the dental system. To combat hypodynamia of the masticatory apparatus with the aim of preventing destructive processes in its structures, a gnathotraining system was developed, including electrical stimulation of the masticatory muscles themselves in physiological parameters, which develops the effect of “imaginary chewing”, and gnathotraining using chewing gum. In addition, functional training of the masticatory apparatus using chewing exercises was proposed. Considering that chewing gum practically does not compensate for the deficit of chewing load observed in modern society, the staff of the Kazan State Medical University and the Kazan National Research Technological University developed the “Denta Fit” dental trainer and a dental training system. It has been established that dental and jaw training stimulates secretion of saliva, its mineralizing potential, functional resistance of tooth enamel, allows achieving a good level of oral hygiene, reduces the rate of increase in the intensity of dental caries, as well as the severity of muscular-articular disorders of the temporomandibular joints, enhances neuromuscular activity of the masticatory muscles and regional blood flow. In children with permanent bite, dental and jaw training maintains the hydrogen index (pH) of oral fluid at a neutral level and provides, in combination with a toothbrush, optimal hygienic dental care, contributes to the formation of a correct dental occlusion. Thus, the effects of increased neuromuscular activity of the masticatory muscles, as well as regional vascular tone, arising during dental and jaw training, indirectly indicate that the dental and jaw system receives adequate mechanical loads necessary for the normal functioning of all its links. The results of the conducted studies indicate the effectiveness and feasibility of using dental training to improve dental status, which serves as a new approach to the prevention and treatment of dental diseases.

An urgent task of biomechanics is the study of the influence of external loads on the human musculoskeletal system, one of the main elements of which is the vertebral column. In this case, research involves considering the spine as a complex system consisting of vertebrae and the intervertebral discs that articulate them. At the moment, there are many works devoted to determining the causes of various abnormalities in the tissue fibers between the vertebrae, which leads to the development of discopathy. Dogs are the most susceptible to such changes due to their genetic predisposition. Thus, in this work, studies were carried out on the cervical spine of three animals: yorkshire terrier, russian toy terrier and half–breed. During the work, numerical modeling of samples was performed using computed tomography data. Computational experiments were carried out using the finite element method and made it possible to determine the stress state taking into account the distribution of the mechanical properties of the material. The tests corresponded to longitudinal compression of the samples. Based on the results obtained, the compressive stress field was determined, the reliability of the values was assessed according to the energy error, and the von Mises stress intensity and the rigidity of the resulting structure were calculated. Analysis of the results showed that the highest stress values are achieved between the vertebrae of the border sections of the cervical spine. On average, a sample of the Yorkshire Terrier breed is predisposed to experience greater stress compared to the results of other dogs in the experimental group. The highest rigidity corresponded to half–breed: twice as much as the average value for dwarf breeds. The distribution of the energy error showed that the areas with the highest values correspond to finite elements at the boundary between different phases of the medium. Thus, the results obtained in the framework of the study make it possible to establish the nature of the distribution of the stress state in the intervertebral discs, as well as to identify the strength indicators of the vertebral columns, taking into account the mechanical properties of various biological tissues.

Inferior alveolar nerve block (IANB) is one of the most common procedures in operative dentistry, and a deep understanding of the normal anatomical variation of the pterygomandibular space (PM) is essential for its safe and successful administration. This cadaveric anatomical study aimed to use A-silicone injections to evaluate the volume of the PM. This study was conducted using 46 human cadaver heads (25 males and 21 females). A craniometric analysis was performed using the cadavers’ ages, the number of silicone cartridges (carpules) used to fill the pterygomandibular space, Izard’s Facial Index (FI), and the Cranial Index (CI). A Halstead mandibular block was performed by injecting 1.7 mL A-silicone cartridges (as an equivalent to standard local aesthetic carpules volume) into the PM. The cured silicone was extracted from the dissected mandibles. The volume (length, width, and thickness) of the extracted silicone and the number of silicone cartridges used to fill the space were evaluated. The results showed that there are statistically significant positive correlations between the CI and the width of the right PM, as well as the width and length of the left PM. A statistically significant correlation was found between the width of the left PM and the age of the cadaveric heads; the higher the age, the thicker the space on both sides. The volume of the PM corresponded to 1.5 cartridges on average.

The morphology of the articular tubercle of the temporal bone varies in the population and is being formed during the growth and development of the patient. When planning and implementing comprehensive dental treatment, it is necessary to take into account the individual parameters of the articular tubercle inclination in order to achieve a predictable result. The aim of the research was to study the values of the articular inclination angle depending on the subjects’ skeletal class. Materials and methods A clinical cross-sectional retrospective simple centric study in which 265 patients participated: 80 men and 185 women.Clinical studies included filling in the dental formula, intraoral photographs of dentition, palpation of the masticatory muscles and the TMJ area, analysis of the jaws plaster models. Each subject underwent electronic axiography with registration of the lower jaw hinge axis movements. The assessment of the angle of articular inclination (SCI) during translational movements was carried out: protrusion-retrusion, right media intrusion, left media intrusion. The skeletal class was evaluated on the basis of cephalometry data by analyzing teleroentgenograms (TRG) in a lateral projection with markers of the hinge-suborbital axis. Result . In the course of the study, the average values of the articular inclination angle were obtained for protrusion-retrusion, right-hand media intrusion, left-hand media intrusion according to the «Skeletal class» criterion. Differences were found between skeletal classes in terms of SCI.During protrusion – retrusion, the SCI values were significantly higher in the subjects with skeletal class II than in the subjects with skeletal class III. It should be noted that the subjects with II skeletal class with protrusion – retrusion had the highest values of SCI than the subjects with I and III skeletal classes, but no significant differences were found. Conclusions The values of the sagittal condular inclination depend on the skeletal class of jaw relationship. A decrease in the values of sagittal condular inclination is a risk factor for the maxillofacial dysfunction development. The lowest values of sagittal condular inclination were observed in subjects with the III skeletal class which requires special attention when diagnosing and treating this risk group. The value of the sagittal condular inclination should be taken into account when modeling the anatomy of orthopedic structures during prosthetic treatment.

The object of the study was senile people, who sought dental orthopedic care in municipal healthcare institutions of the town of Cheboksary, the Chuvash Republic. The sample size was 1 000 people. The obtained quantitative indicators were subjected to statistical processing using parametric and nonparametric statistical methods. The analysis of mounted orthopedic dent prosthetic structures manufactured and installed in elderly and senile patients shows that the choice of material and method of manufacture is largely determined by such a social factor as the average monthly income. This, in turn, largely depends on income-generating employment and the possibility of obtaining additional financial support from family members in which the patient lives. Social factors have a significant impact on the quality of life in elderly and senile people.

BACKGROUND:One of the most popular methods of local anesthesia in dentistry, inferior alveolar nerve block (IANB) involves the blockade of the inferior alveolar nerve (IAN) and lingual nerve (LN) in the pterygomandibular space. Despite the large number of works describing the contents of this space, the spatial displacements of the anatomical structures of this area at different positions of the mandible have not been sufficiently studied. The aim of our study was to study the spatial movements of the IAN and inferior alveolar artery (IAA) at various positions of the mandible using computer simulation and finite element analysis to find the safest way to conduct IANB. MATERIALS AND METHODS:Reverse engineering was used to create a model of the cranial base and the mandible based on computed tomography (CT) data obtained from patient N (male, 24 years old), the arteries of the head and neck were designed from the data of multiphase angiography of patient M (female, 61 years old). Masticatory muscles, sphenomandibular ligament, temporomandibular joint and mandibular nerve were modeled in the SolidWorks software package based on an open database of anatomical structures. The finite element grid was generated in the Solidworks software. In the first series of experiments, the displacement of the mandible was modeled along the vertical axis down by 48 mm (maximum opening of the mouth), in the second series, the jaw was displaced vertically by 48 mm with a simultaneous transversal movement of 10 mm, in the third series, the jaw was displaced along the vertical axis down by 34 mm and transversally by 22 mm. RESULTS:The largest distance between IAN and IAA was noted in the third series of experiments. The distance between the nerve and the vessel was minimal in the first series, with an open mouth without lateral displacements. CONCLUSION:The generated computer model opens new possibilities for studying the dynamic anatomy of the pterygomandibular space. The results of this study can be used for further experimental and clinical trials to find the safest approach to the implementation of IANB, as well as applied in the practice of the educational process.

The object of the study was senile people, who sought dental orthopedic care in municipal healthcare institutions of the town of Cheboksary, the Chuvash Republic. The sample size was 1 000 people. The obtained quantitative indicators were subjected to statistical processing using parametric and nonparametric statistical methods. The analysis of mounted orthopedic dent prosthetic structures manufactured and installed in elderly and senile patients shows that the choice of material and method of manufacture is largely determined by such a social factor as the average monthly income. This, in turn, largely depends on income-generating employment and the possibility of obtaining additional fi nancial support from family members in which the patient lives. Social factors have a significant impact on the quality of life in elderly and senile people. Объектом изучения стали люди пожилого и старческого возраста, обратившиеся за стоматологической ортопедической помощью в муниципальные учреждения здравоохранения (Чебоксары, Чувашская Республика). Размер выборки составил 1 тыс. человек. Полученные количественные показатели были подвергнуты статистической обработке с использованием параметрических и непараметрических методов. Проведенный анализ установленных ортопедических зубопротезных конструкций, изготовленных и установленных пациентам пожилого и старческого возраста, показал, что выбор материала и способа изготовления во многом определяется таким социальным фактором, как среднемесячный доход. Это, в свою очередь, во многом зависит от трудовой занятости, приносящей доход, и возможности получения дополнительной финансовой поддержки от членов семьи, в которой пациент проживает. Социальные факторы оказывают существенное влияние на качество жизни людей пожилого и старческого возраста.

Working in intensive care units (ICUs) is stressful and potentially leads to various psycho-emotional disorders. Today, this issue represents a serious concern to the healthcare sector and affects the quality of healthcare provided. This study aimed to assess and compare the psycho-emotional state in COVID-19 and non-COVID-19 hospitals' ICU healthcare workers (HCWs). From January to July 2021, we conducted an anonymous cross-sectional web survey of ICU physicians and nurses (N = 1259) of various hospitals in a metropolis with a population of over 10 million people. The statistical distributions of non-COVID-19 ICU HCWs showed the following results: emotional exhaustion levels (low 14.6%, average 30.8%, and high 54.6%); depersonalization levels (low 11.6%, average 16.5%, and high 71.9%); and reduced personal accomplishment levels (low 23.5%, average 40.3%, and high 36.2%). The statistical distributions of COVID-19 ICU HCWs showed the following results: emotional exhaustion levels (low 16.5%, average 31.5%, and high 52%); depersonalization levels (low 7.4%, average 9.4%, and high 83.1%); and reduced personal accomplishment levels (low 25.4%, average 45.4%, and high 29.1%). This study found a strong correlation between emotional exhaustion, aggression, and depersonalization in non-COVID-19 ICU HCWs and also found a correlation between their age, aggression, emotional exhaustion, and occupational stress.

Background: Providing regional anesthesia skills shaping remains relevant nowadays. A number of studies show that dentists have difficulties with these working independently. The study aim is the comparative analysis of the results of mandibular anesthesia (IANB) manual-skills shaping among dentists on plastic models and cadavers. Methods: In total, 999 participants were training in the skills of mandibular anesthesia from 2017 to 2021. The participants were divided in a random way into two groups: 700 participants were trained on plastic models, and 299 were trained on the cadaver material. After a lecture on the clinical and anatomical guidelines for IANB, a demonstration of the technique was provided, with subsequent testing of the injection technique. Satisfaction with the aspects of the training was assessed using the Likert scale. Results: the analysis of average values showed that participants from the group in which the manual skills were practiced on cadavers were more satisfied with the main aspects of the training, according to the sum of the main criteria of the modified scale. Conclusions: The important advantages of cadaver educational technology are that the sensations of tissue resistance are identical to natural ones, the individuality of each object, and the possibility of the visual study of the anesthesia technique, by dissection of the needle course and the location of the anesthetic depot.

Porcelain fused to metal is widespread dental prosthetic restoration. The survival rate of metal-ceramic restorations depends not only on the qualifications of dentists, dental technicians but also on the adhesive strength of ceramics to a metal frame. The goal of the research is to determine the optimal parameters of the surface machining of the metal frame to increase the adhesion of metal to ceramics. Adhesion of cobalt-chromium alloy and ceramics was investigated. A profilometer and a scanning electron microscope were used to analyze the morphology. To estimate the adhesion the shear strength was measured by the method based on ASTM D1002-10. A method of surface microrelief formation of metal samples by plasma-electrolyte treatment has been developed. Regimes for plasma-electrolyte surface treatment were investigated according to current-voltage characteristics and a surface roughness parameter. The samples were subjected to different surface machining techniques such as polishing, milling, sandblasting (so-called traditional methods), and plasma-electrolyte processing. Morphology of the surface for all samples was studied and the difference in microrelief was shown. The roughness and adhesive strength were measured for samples either. As a result, the mode for plasma- electrolytic surface treatment under which the adhesive strength was increased up to 183% (compared with the traditional methods) was found.

The TMJ is a complex joint in which movements are carried out in three planes. The pairing of the joint and complex combined movements are factors that complicate the clinical and instrumental analysis of patients. Each of the axiographic tests carries a certain range of information and it is necessary to evaluate the characteristics of various movements in order to fully understand the possibilities of using the axiography method in the daily work of clinicians.

An impact of the endogenous intoxication on the treatment efficacy of the lower jaw fractures is not well-studied. Therefore, the aim of the present study was to examine the effect of endogenous intoxication on the dynamics of recovery from traumatic injuries of the lower jaw. Thirty-two patients with the open bilateral traumatic fracture of the lower jaw were enrolled in present study. All the patients were subjected for general blood analysis; the biochemical and hemostasis parameters and leukocyte intoxication index were also included. The patients were divided into the 3 experimental groups. Group 1 was composed of patients (26.3%) with low leukocyte intoxication index (< 1.0). The patients included into group 2 (47.4%) exhibited the index ranging from 1.0 to 1.4. For the patients included in group 3 (26.3%), this index exceeded 1.5. All the examinations were performed on day 1 after the injury and on day 5 after the reposition of fragments of the lower jaw. Thirteen patients were also examined for the macro- and microelement content and ratios in the oral fluid. We observed that due to the adverse effects of endogenous intoxication, the patient may develop the opposite reactions, including the restoration to normal values or development of sensitization of the body and tissue necrobiosis. We also found that significant changes in leukocyte intoxication index during the recovery period in all experimental groups. For example, in group 1, the leukocyte intoxication index decreased up to 0.88 ± 0.05 (p < 0.001), whereas in group 2, this index decreased up to 1.27 ± 0.04 (p < 0.001). Group 3 demonstrated a substantial decreased of this index, e.g., 2.0 ± 0.22 (p < 0.05). The precise molecular mechanisms of this phenomenon are unknown and remain to be further elucidated. We showed here for the first time that endogenous intoxication during the traumatic injuries of the lower jaw might trigger the development of sensitization or necrobiosis of the surrounding tissues, which has a significant impact on duration of the treatment and recovery period.

In the scientific literature, one can find conflicting assumptions about the presence of «proper mental bone» and «upper and lower lingual canals», which make up a separate ossified area in the chin of the mandible and the system of blood supply and innervation. However, calling these lesions «lingual canals» or «incisal canals», as is often found in various articles, is incorrect based on the position of International Anatomical Terminology. This is due to the lack of topographic reference in the term, which can equally be understood as the canal of the tongue, the neurovascular bundle of the same name, and the root canal system of the teeth of the lower jaw and can also be associated with the maxilla. We searched for information in English, without time limits, in the PubMed Central database, and searched on Google and analyzed the bibliography, relevant studies and reviews. The selection of publications was carried out by request «mental spine canals», 58 articles were found in PubMed, of which 21 were relevant. For the analysis, publications were selected that described in detail the anatomical, clinical and radiological features of the structure of the anterior part of the mandible. As a result of previous studies and the study of literature data, the intraosseous structures of the anterior part of the lower jaw were refined and classified, which solve not only terminological disputes, but also are important clinical guidelines for endodontic treatment, dental implantation and local anesthesia.

The temporomandibular joint is paired, a complex formation of an ellipsoid shape, which is formed by the articular head of the lower jaw, the mandibular fossa and the articular tubercle of the temporal bone, covered with fibrous cartilage. There are two types of movements in the temporomandibular joint: translation and rotation, which implement protrusion-retrusion, right and left mediotrusion, and opening-closing. Computerized axiography is used for assessment of the mandibular movements and the patient’s skeletal parameters. This type of examination allows you to adjust the articulator for an individual function and to study the qualitative and quantitative characteristics of the temporomandibular joint.

In dental implantology the treatment planning is the most important item for surgery success as well as for functionality and aesthetics of denture. The current problem is to determine the implant position intraoperatively. On dental market there are many companies offering the different variants of navigation surgery, including surgical guides. The purpose of this study is to create universal classification of surgical guide application for dental implantation based on clinical setting and the individual anatomy of the patient which simplifies the medical activities and predictably performs the treatment protocol.

To improve the quality and effectiveness of medical care for patients with inflammatory periodontal diseases, it is necessary to search for new approaches in both diagnosis and treatment. The aim of our study is to determine the effect of the diode laser on the pathogenic microflora of periodontal pockets and root canals in patients with endo-periodontal lesions (EPL). We carried out a comparative assessment of the bacterial contents of the root canals and periodontal pockets by polymerase chain reaction (PCR) before and after treatment with a diode laser (Doctor Smile Simpler, wavelength 980 nm) for 54 patients with EPL. The control group consisted of 56 patients who were treated according to the generally accepted method, including professional oral hygiene, endodontic treatment, and curettage of periodontal pockets. Evaluation criteria were a qualitative assessment of the content of periodontopathogens in the root canal and periodontal pocket before and after and treatment. As a result of our study, we found a statistically significant (p<0.01) reduction in the colonization of periodontal pockets and root canals in patients with EPL after laser decontamination. The high technological effectiveness of the methods used in combination with the low risk of complications at the stages of endodontic and periodontological treatment provides an antibacterial effect and reduces the duration of inflammation. The results of treatment of patients using a diode laser give reason to recommend their use in the dental practice.

The oral cavity is one of the most complex microbial environments; however, the complex nature of the salivary microbiota and the level of inorganic anions in the saliva of subjects with and without gastroesophageal reflux disease (GERD) are poorly understood. The primary goals of this pilot research were to assess differences in salivary bacterial community composition and inorganic anion concentrations between patients with GERD and GERD-free people. Thus, the salivary microbiota within both groups was dominated by these genera: Streptococcus, Prevotella, Porphyromonas, Veillonella, Neisseria, Haemophilus, Fusobacterium, Rothia, and Leptotrichia. However, the relative abundances of the genera Actinomyces, Atopobium, Stomatobaculum, Ruminococcaceae_[G-2], Veillonella, and Leptotrichia were significantly higher in the saliva samples of patients with GERD, while the genera Porphyromonas, Gemella, Peptostreptococcus, and Neisseria were less abundant in this group. The concentrations of chloride, phosphate, and sulphate ions in the human saliva varied among all subjects and sampling time. These results broaden our knowledge of the salivary microbial community composition and chemistry of saliva of patients with GERD and GERD-free individuals.