Modern structural materials are represented by a variety of polymer materials used for dental patients’ rehabilitation. They differ not only in physico-chemical properties, but also in microbiological properties, which is one of the reasons why these materials are chosen. The study focused on the microbial adhesion of clinical isolates of normal (5 types), periodontopathogenic (2 types), and fungal (2 types) microbiotas to various materials based on polymethylmethacrylate (PMMA) intended for traditional (cold-cured and hot-cured polymers), computer-aided subtractive and additive manufacturing. A comparative analysis was carried out on the studied samples of polymer materials according to the microorganisms’ adhesion index (AI). The lowest level of microorganisms’ AI of the three types of microbiotas was determined in relation to materials for additive manufacturing. The AI of hot-cured polymers, as well as materials for subtractive manufacturing, corresponded to the average level. The highest level of microorganisms’ adhesion was found in cold-cured polymers. Significant differences in AI for materials of the same technological production type (different manufacturers) were also determined. The tendency of significant differences in the indicators of the microorganisms’ adhesion level for the studied polymer materials on the basis of the type of production technology was determined.

(1) Background: The paper addresses the computer simulation and prediction of the service life of the base of removable complete dentures (RCDs) under typical loads caused by biting and chewing food. For this purpose, the finite element method (FEM) was used. It is assumed that various blocks of teeth, such as incisors, canines, premolars and molars, are subjected to cyclic impacts during a human life. (2) Methods: Both symmetric and asymmetric mastication (two- and one-sided loads, respectively) cases were considered. The load level was assumed to be 100 N, which corresponds to the average muscular compression force of typical human jaws. (3) Results: The FEM analysis of the stress–strain state evolution for RCDs under cyclic loads was carried out. Maps of equivalent lines were drawn for the denture base in terms of its durability. A multi-axial criterion was implemented to determine the number of cycles prior to failure by the mechanism of a normal opening mode crack. The FEM-based assessment of the service life of RCDs enabled us to establish the critical stress concentration areas, thereby allowing for further planning for the correction of an occlusal scheme or teeth inclinations. As a result, the service life of RCDs under cyclic loading can be improved. (4) Conclusions: An algorithm for designing RCDs in the case of edentulism based on the FEM simulation using commercial software as part of the procedure is proposed.

The place of high-tech methods of molecular biology in clinical laboratory diagnostics of various diseases and the development of a system of biomarkers as an important component of diagnostic research is currently attracting the closest attention of the scientific community. In this paper, an attempt is made to use high-tech metagenomic analysis to solve problems that arise due to the high frequency of association of periodontal diseases with systemic pathology, in particular, with type 2 diabetes mellitus. The aim of the study was to determine the taxonomic and metabolic features of the microbiome of periodontal tissues in periodontal diseases associated with type 2 diabetes mellitus, as a model of the ratio of local and systemic effects of periodontal pathogenic bacteria. The study included 16S shotgun sequencing of bacterial DNA as part of biological material from periodontal pockets/dentoalveolar furrows of 46 people - 15 patients with chronic periodontitis associated with type 2 diabetes mellitus, 15 patients with chronic periodontitis unrelated to systemic pathology, as well as 16 healthy people in the control group, followed by bioinformatic processing of the data obtained. The obtained data allowed us to establish the taxonomic features of the periodontal microbiome in the association of chronic periodontitis with type 2 diabetes mellitus, which included the predominance of representatives of the families Prevotellaceae and Spirochaetaceae in its composition. The features of metabolic processes in periodontal tissues with the participation of the microbiome were also revealed, which consisted in an increase in the exchange of cysteine and methionine against the background of a decrease in the metabolism of pyrimidine, methane, sphingolipids, and the synthesis of fatty acids, which are of diagnostic value in assessing the condition of patients with type 2 diabetes mellitus.

Infectious and inflammatory periodontal diseases are among the common causes of tooth loss, highlighting the need for accessible biomarkers for diagnosis and monitoring. Saliva is a bioinformative material; however, the diagnostic relevance of immunoglobulins in gingivitis and periodontitis remains unproven. Purpose — To assess the association between salivary IgA, IgM, IgG and secretory sIgA levels and clinical signs of periodontal pathology. Materials and methods. A total of 600 residents of Khabarovsk Krai from key WHO age groups were examined; groups were formed on an ordinal scale: healthy, gingivitis, and mild, moderate, and severe periodontitis. The following were performed: assessment of clinical indices OHI-S, CPITN, PMA, and PBI; microbiological examination of pathological periodontal pockets; and measurement of salivary IgA, IgM, IgG and sIgA levels by ELISA. Results. Spearman correlation analysis showed a strong positive association between periodontitis severity and CPITN (ρ=0.636), a moderate association with PBI (ρ=0.479) and PMA (ρ=0.434), reflecting the role of inflammation and bleeding in disease progression; and a weak association with OHI-S (ρ=0.246). According to ROC analysis, sIgA had a moderate diagnostic value in severe periodontitis (AUC=0.72). The optimal sIgA cut-off was 305 mg/L, with sensitivity 78% and specificity 65%. The combination of sIgA and IgM in a multivariable logistic regression model showed high predictive performance (AUC=0.81). Each 1 mg/L increase in secretory sIgA increased the odds of periodontitis by 0.4% (OR=1.004). Between-group differences in salivary IgA, IgM, IgG and sIgA levels by disease severity were not statistically significant. A strong association with severe chronic periodontitis was demonstrated for the E. coli + Leptotrichia spp. combination (OR=3.00); significant predictors of severity included Enterococcus faecalis + Leptotrichia spp. (OR=2.34) and Staphylococcus aureus + Leptotrichia spp. (OR=1.92). Conclusion. Comparative analysis of OHI-S, CPITN, PMA and PBI indices, the microbiological profile of periodontal pocket associations, and humoral salivary biomarkers helps to clarify the contribution of individual parameters to the diagnosis and monitoring of infectious and inflammatory periodontal diseases.

Relevance. The treatment of periodontal diseases currently requires professional oral hygiene procedures involving various antiseptics used as mouth rinses and irrigants. Objective. To provide an experimental and microbiological rationale for the use of domestically produced periodontal antiseptics and their combinations to enhance antimicrobial efficacy through the application of innovative microbiological culturomics technologies. Materials and methods. To study the antimicrobial effects of antiseptics, an advanced RTS bioreactor (BioSan, Latvia) was employed. Unlike the previous RTS-1 monocultivator, the new model comprises eight integrated units. Each unit incorporates an innovative agitation mechanism for mixing microbial cultures, with digital data processing and real-time display. The following quaternary ammonium compound (QAC) antiseptics were tested: benzyldimethyl [3-(myristoylamino)propyl]ammonium chloride (Miramistin), benzalkonium chloride, and cetylpyridinium chloride, as well as chlorhexidine digluconate, used as the most common reference agent. The test strains included S. aureus ATCC 25993, E. faecalis , P. intermedia , F. necrophorum 89-5 (Federal Scientific Centre VIEV, FSC VIEV, Moscow, Russia), C. albicans ATCC 10231, and C. krusei Harvard ATCC 625. Results. Miramistin demonstrated superior antimicrobial efficacy compared to other QAC antiseptics when analyzing microbial growth kinetics. Bacteriostatic effects were achieved at concentrations ranging from 0.012% to 0.05%, while bactericidal effects occurred within 0.05–0.10%. For fungal cultures, fungistatic activity was observed at 0.05–0.10% concentrations, and fungicidal activity at 0.1–0.2%. Conclusion. Chlorhexidine showed slightly lower efficacy than Miramistin, particularly against fungal isolates, though it outperformed other QAC-based agents. Our findings indicate that QAC antiseptics – especially miramistin – have a milder impact on the composition of the oral microbiota than chlorhexidine.