[Principles of evidence-based medicine in dentistry and Maxillo-facial surgery].

Evidence based medicine is the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients.

[Reaction of bone tissue elements on synthetic bioresorbable materials based on lactic and glycolic acids].

The aim of the study was to evaluate the adverse effects of synthetic polymeric bioresorbable materials based on lactic and glycolic acids on the bone tissue. The study was carried-out on 40 Wister-line rats. Four types of bioresorbable polymeric materials were implanted: PolyLactide Glycolide Acid (PLGA), Poly-L-Lactide Acid (PLLA); Poly-96L/4D-Lactide Acid (96/4 PLDLA); Poly-70L/30D-Lactide Acid (70/30 PLDLA). The results showed connective tissue formation (fibrointegration) bordering bone adjacent to implanted materials. This proved the materials to cause pathogenic influence on the bone which mechanisms are described in the article.

[Comparative study of osteoplastic materials based on chitosan, alginate or fibrin with tricalcium phosphate].

The study presents comparative analysis of porous composites made of chitosan, alginate, fibrin with beta-tricalcium phosphate. Histological findings on Wistar rat condyles showed that fibrin-beta-TCP-based composite had the most effective positive biological response.

[Experimental assessment of biodegradable polyglycolic and polylactic acid polymers for medical use].

Interrelations of biodegradable poliglicolic and polilactic acid polymers in various proportions implanted in standardized bone defects were evaluated in animal model with 40 Wister line rats. During 10 month follow-up period bone capsule surrounded all implants, but timing of bone formation and bone quality varied significantly being optimal in LactoSorb group. Destructive features of polymers were also seen in implant-bone contact area defined as inflammation, fibrous tissue formation and cell dystrophy.

[New type titan alloy with shape memory for use in dental implantology].

The paper summarizes the results of in vitro and in vivo studies that have proved biocompatibility and medical safety of Ta and Ti-Nb-Ta-bases alloys. According to some in vitro data Ti-Nb-Ta-based alloy possesses certain advantages when comparing to Ta-based. In particular, it contributes to elevation of viability of cellular elements and to definite increase of their adhesive potential.

[Surgical tactics by various ameloblastic tumors].

Ameloblastoma and ameloblastic fibroma are benign odontogenous tumors of the jaws with local destructive growth, prone to recurrence. They have various typical radiological and histological features. Surgical tactic generally includes partial resection of the affected jaw. Immunohistochemical study of the tumor tissues allows assessing the expression of tumor progression markers and forecasting tumor growth thus providing individual choice of surgical tactics. Our experience in treatment of ameloblastic tumors showed total biopsy with osseous surgical margins resection to be sufficient for normal bone structure remodeling in some patients.

[Perspectives of use of polytetrafluoroethylene with nanostructured surface in dentistry].

The perspectives of use of porous polytetrafluorethilen (PTPE) with modified surface combined with mesenchymal stem cells for tissue-engineering constructions were studied. The paper also describes the mode of PTPE surface modification consisting in nanostructured metallic or ceramic layer application resulting in biocompatibility and surface adhesion rates increase. The magnetic atomizing of Ti and Ti-Ca-P-C-O-N nanolayers enhances the material integration potential as well as adhesion rates thus making it perspective when combined with mesenchymal stem cells for bone defects plasty.

[Keratin 8 expression in mouth mucosa hyperkeratosis and squamous cell carcinoma ].

The immunohistochemical study of proliferation and intermediate filament--keratin 8 expressions at oral hyperkeratosis and oral Squamous cell carcinoma (OSCC) has been carried out. It has been shown, that the specific character of keratin 8 expressions can be used in differential diagnosis between oral hyperkeratosis and OSCC. Different types of oral hyperkeratosis (without atypia, SIN1, SIN2 and SIN3) can be differentiated by Ki-67 and keratin 8. We have found the moderate positive correlation between proliferation and a keratin 8 expression in neoplastic epithelial cells.

[Implants integration into bone tissue: theoretical aspects of the problem].

It was analyzed the status of dental implants integration into bone tissue problem. The concept of stages and mechanisms of development of integration process in the implant-bone interface based on literature data and own study was presented.

[Comparative histomorphological analysis of bone fragments consolidation in compression and non-compression mandible osteosynthesis].

On experimentally produced model of mandible fractures (on 18 rabbits) the efficacy of compression osteosynthesis was compared with fixation by usual plates (non-compression osteosynthesis). As was shown by histological study and morphometrical analysis of tissue structures from the region of experimentally isolated in rabbit mandible bone fragments fixed by microdevices for compression and non-compression osteosynthesis in cases of compression osteosynthesis if compared with non-compression osteosynthesis at the experimental terms of 2, 3 and 4 months more intensive new formation and secondary rebuilding of bone tissue with its compactification in the region of cortical layer happened. Histological study and morphometrical analysis of histological pictures showed that reparative osteosynthesis processes were activated in cases of compression osteogenesis not only in cortical but also in sponge layer that together with contact enforcing of the edge of experimentally isolated bone fragment with maternal bone and bone splinters fixation strengthening stipulated for integral positive effect in the form of bone integrity restoration acceleration. In case of non-compression osteosynthesis the processes of reparative bone formation were observed mainly in cortical layer region, in sponge layers they were expressed poorly.

[Experimental study of dental implants with nanostructured non-resorbable coating integration into bone tissue].

In 2 dogs on both sides of mandible premolars were removed. In 3 months after dental alveolus healing intraosseous screwdriver dental implants (Konmet, Russia) were installed in the place of the removed teeth. Analogous operation was done on the contralateral side: the same type of implants were installed but with new nanostructured multifunctional biocompatible non-resorbable coating (MBNC) of the Ti-Ca-P-C-O-N composition. The animals were taken out of the experiment in 4 months after implants installation and implant-bone blocks were studied by SEM-method. According to the SEM-data in the region of the contact of implant-bone without new MBNC only fibrous connective tissue was formed. In case when MBNC was used the close welding of bone tissue with implant surface was observed that was considered as sign of osteointegration.

[Influence of allogenic and autologic multipotent stromal cells of adipose tissue upon bone tissue regeneration in the rabbit mandible angle defect].

Reconstructive surgery often collides with complicated task of defect recovery in the situation of deficit of maxillofacial skeleton tissues, that leads to necessary search of accessible cells source with osteogenic potentials and proper substrate for cell transplantation. In the study the regeneratory potential of stromal cells of adipose tissue was tested in the rabbit model of mandible through angle defect. Cells of allogenic and autologic nature stimulated reparative osteogenesis but their influence upon bone matrix maturation was different. When the construction with allogenic cells was transplanted reaction of its rejection was not detected on histological level.

[Critical bone defects elimination by bioengineering construction upon non-resorbable polymeric base with the use of autogenic multipotent stromal cells from adipose tissue].

On 8 rabbits with experimentally produced critical defects of calvarium plastics of the defects was performed by bioengineering constructions based upon porous polytetrafluoroethylene with multifunctional nanostructured non-resorbable cover Ti-C-Ca-P-O-N and autogenic stromal cells from adipose tissue (the main group -4 rabbits). In the reference group (4 rabbits) the defects were repaired by abiologic implants. At the terms of 3 and 6 months in the main group under implants the formation of the full value bone regenerate was seen in the region of calvarium defects. In the reference group in the bone defects the regenerate from rough fibrose connective tissue was formed.

[Use of mesenchymal stem cells for reparative processes activation in bone jaw tissue in experimental conditions].

In experiment on 12 Chinchilla rabbits dynamics of reparative regeneration was studied at the terms 2 and 4 months. Bone defect in mandible corner was closed by osteoplastic material Gapkol which was covered from inside by allogenic or autologic stem cells received from rabbit adipose tissue. The results of the ray tracing methods of study were verified by SEM and histological methods.

[Microflora dynamics in purulent skin wound in rats after ozonized perftorane applications].

In 30 Wistar rats divided in 3 groups with 10 rats in each skin defects were reproduced under anaesthesia and wound surface was fixed with the help of plastic rings. The wounds were contaminated with microbe dredge consisting of St. aureus, Ps. aeruginosa and E. coli in the concentration of 10(9) cells/ml. After 24, 48, 72, 96 and 120 hours the wound was irrigated with 10-15 ml of the following solutions: in the 1st group - commercial perftorane solution, in the 2nd group - ozonized perftorane, in the 3rd group - physiological solution. Hard medium inoculation let determine total number of growing microbe colonies. The material was taken each 3rd day. 9 experimental series were executed with the total length of experiment equal to 30 days. It was established that from 15th day of the experiment in the group with ozonized perftorane irrigations the mean number of microorganisms in the wound was reduced, granulation tissue growth and epithelization were speeded up if compared with the groups of animals irrigated with physiological solution and non-ozonized perftorane. Ozone action was connected not only with its bactericidal properties but in considerable degree with comprehensive local immunity activation.

[Titanium implants integration into mandible distract regenerate].

In experiment on 20 rabbits with distract regenerates in the region of mandible body osteotomy the correlation between the efficacy of titanium implants (introduced into regenerate) integration and the degree of regenerate osseous material differentiation was investigated. Implants integration fixed in 7 and 20 days after distraction process discontinuance passed considerably more efficiently than in rabbits with implants fixed 1 day after distraction process discontinuance. It expressed itself with intensive development and maturation of osseous regenerate around implants and with tendency to "solder" of newly formed bone and implant's surface, i.e. to osteointegration. Higher the level of newly formed osseous material maturity in the implantation moment - more effective implant integration will be.

[Bone regenerate structural organization in experimentally reproduced defects of mandible branches under xenogenic stromal cells influence].

In experiment on rabbits by histomorphometric method it was shown that after the use during 4 months of titanium plate with the culture of marrow mesenchymal stromal cells there happened full infill of mandible defect by lamellar bone tissue. In control group (titanium plate with inactivated culture of cells) the defect was replaced by regenerate, the most part of it was rough fibrous connective tissue. In experimental group in the central parts of the defect regenerate were characterized by bigger weight of lamellar bone matrix if compared with the peripheral parts of the defect that testified to higher level of its differentiation. Use of stem cells on titanium carrier led in 4 months experiment to full infill of jaw defect by lamellar bone tissue.

[Species composition of anaerobic microflora in parodontal pocket depending upon disease stage].

With the help of polymerase chain reaction (PCR) the dynamic of species composition of anaerobic microflora in cases of generalized parodontitis was established. It was detected that disease severity increase was followed by the increase of the number of anaerobic microflora species in parodontal pocket; at that it was impossible to connect the presence of some determined type of microorganism with the inflammatory parodontal process intensity. It was shown that proteins fimbrilin and gingipain were not the only parodontitis pathogenic factors although the first one (fimbrilin) could be connected with aggressive disease flow. The suggested PCR scheme could be useful for early disease stage diagnostic and substantiation of antimicrobial therapy method selection.

[Bone defects of ramus mandibulae healing in rabbits under bioengineering constructions from titanium and gold alloy with xenogenic mesenchymal stem cells].

Aim of the study was substantiation in experiments on rabbit ramus mandibulae of the method of mesenchymal stem cells (MSC) on the carrier from titanium and gold alloy for reparative osteogenesis enforcement. There was shown stimulating action of the MSC implantation in the bone wound upon reparative osteogenesis at the terms from 1 to 4 months. It was concluded that implants from titanium and gold alloy may be used as carrier for MSC for bone tissue reparative regeneration stimulation.