[Technologies for early diagnosis of oral mucosal diseases]. / Tekhnologii rannei diagnostiki patologicheskikh protsessov slizistoi obolochki rta.

OBJECTIVE: Expert evaluation of minimally invasive techniques in the diagnostic algorithm of pathological processes of the oral mucosa. MATERIAL AND METHODS: Fluorescence stomatoscopy of the oral mucosa of 1520 patients aged 18-65 years with analysis of color code of optical images was carried out. The nature of the disease was established by liquid cytology. PCR diagnostics was performed to detect oral-potential disorders provoked by human papillomavirus and Epstein-Barr virus. RESULTS: Analysis of optical images of the normal and pathologically affected oral mucosa allows determining the possibilities of the technique to detect a hidden pathological process at the preclinical level. The results of liquid cytology in each case confirm the nature and depth of the pathological process. PCR diagnostics determines the presence of risk factors (Epstein-Barr virus, human papilloma virus 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59), contributing to the malignant transformation. CONCLUSIONS: A comprehensive examination of the oral mucosa using clinical-laboratory methods of visualizing pathological processes contributes to their early diagnosis, reduces the risk of advanced cases of oncopathology and allows extending life expectancy.

[Comparative analysis of different types of implant-abutment interface on the basis of three-dimensional finite element analysis data]. / Sravnitel'nyi analiz biomekhaniki pri razlichnykh uzlakh sopriazheniia implantata i abatmenta na osnovanii dannykh trekhmernogo konechno-élementnogo modelirovaniia.

The purpose of the study was to perform a comparative static and dynamic finite element analysis of various taper and cylindrical implant-abutment connections in three-dimensional (3D) models including: abutment, fixing screw, implant, cortical bone, cancellous bone. 3D implant model was IRIS LIKO-M system (Russia) 4 mm diameter and 10 mm length. All the models (M1-M6) were built in the same way. While maintaining the external design of IRIS LIKO-M implant, they differed only by taper angle 1.25°, 5°, 9° and its height - 0.45 and 1.85 mm; the models (M7, M8) had a cylindrical connection with a joint height of 0.45 and 1.85 mm. The bone model was 6 mm width, included cortical layer was 3 mm and the inner cancellous bone. The results of static FEA of an occlusal load showed that implant with 1.85 mm abutment connection transfer strain from edge of a cortical bone to its inner layer thus preventing marginal bone resorption. The best results showed implant model with conical taper 5° and 1.85 mm height: the smallest von Mises stress in cortical layer at tightening of the fixing screw and at masticatory load, and the larger margin of safety of an implant, the abutment and the fixing screw. The results of dynamic FEA of implant with cylindrical connection demonstrate that the gap between an abutment and an implant may occur and lead to fixing screw loosening or fracture. At the same time, the implant design with knot of interface of conical type 5° remains tight at dynamic load.

[Mathematical rationale and results of clinical use of IRIS short implants]. / Matematicheskoe obosnovanie i rezul'taty klinicheskogo ispol'zovaniia korotkikh implantatov IRIS.

The aim of the study was to provide a mathematical justification of the possibility of using 6.5 mm IRIS implants and to evaluate the results of orthopedic treatment in patients with partial loss of teeth. For the calculations was constructed of a composite three-dimensional computer models: the abutment screw-implant-bone. A total of 3 models were prepared: M1-implant in the spongy bone tissue, this model corresponds to the implantation on the HF when replacing one molar; M2-2 implants in the spongy bone tissue located at a distance of 4 mm connected via abutments, this model corresponds to the implantation of RF when replacing two molars; M3-implant in the cortical bone tissue, this model corresponds to the implantation of LF when replacing one molar. Loading of implants was carried out by occlusive force applied to its end surface. The results of the calculations showed that the equivalent stresses and limiting stresses of compression-tension are within the permissible values, which were obtained by us earlier in respect of the irregular implants and are consistent with the results of calculations for other systems of short implants. The clinical part of the work consisted in the treatment of 27 patients with partial loss of teeth, who had 41 iris evolution implants with a diameter of 5 mm, length of 6.5 mm after 3 years, there was a slow bone resorption in the cervical region not exceeding 0.35 mm, which corresponds to generally accepted international standards. During the first three years of operation there were no cases of loss of established implants. Thus, the data of mathematical modeling by finite element method and retrospective three-year analysis of prosthetics on IRIS evolution implants with length of 6.5 mm showed that the use of short implants in the recovery of upper and lower jaw molars is an effective method with a high success rate at long - term and resorption level of 0.34 mm.

[Development and preclinical studies of insulating membranes based on poly-3-hydroxybutyrate-co-3-hydroxyvalerate for guided bone regeneration].

Bone tissue damages are one of the dominant causes of temporary disability and developmental disability. Currently, there are some methods of guided bone regeneration employing different osteoplastic materials and insulation membranes used in surgery. In this study, we have developed a method of preparation of porous membranes from the biopolymer poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV), produced by a strain of Azotobacter chroococcum 7B. The biocompatibility of the porous membranes was investigated in vitro using mesenchymal stem cells (MSCs) and in vivo on laboratory animals. The cytotoxicity test showed the possibility of cell attachment on membrane and histological studies confirmed good insulating properties the material. The data obtained demonstrate the high biocompatibility and the potential application of insulating membranes based on PHBV in bone tissue engineering.