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The main causative factors of microbial injury of periodontal tissues during endodontic treatment and ways of its prevention we are discussed. The own microbiological investigation results and bibliographic data we are presented. Microbiological investigation of debris extruded during root canal instrumentation using EDTA and sodium hypochlorite was executed by authors.

The aim of thes; study was to observe initial stage of wedge-shaped defects under scanning electron microscopy without prior samples preparation. There were revealed special features of structure of enamel and cement at initial stage of wedge-shaped defects in comparison to normal tissues.

The 970 nm diode laser and 3% sodium hypochlorite antiseptic properties comparative estimation has been investigated. The investigated methods antimicrobial efficiency estimation has been made by means of microbiological study and by means of fluorescent laser analysis. It has been proved that laser radiation using allows the medicament treatment efficiency but doesn't assure provide total root canals sterility.

A clinical epidemiologic study was made among 432 Moscow students and as a part of it was found the high prevalence rate of pathologies of dentition and variety of nosologic forms. The most common cases were: caries, periodontal disease, deformity and anomalies of tooth position. These findings were necessary to estimate the need of all types of dentistry for Moscow students. It was specified that 43% of students were in need of filling and dental restoration, 35% were in need of crowns of tooth, 22% were in need of dental restoration by means of orthopedic constructions. Endodontic dentistry was necessary for 31% of students, surgical removal - for 8%, periodontal dentistry - for 37%.

For assessment of tooth canal mechanical preparation method influence upon frequency of pain emergence after endodontic treatment, laboratory and clinical evaluation of sound tools of the Sonic system, ultrasound tools of the Satelec Suprasson system, full-wind tools of Pro Taper and System GT as well as handy K-files was performed. It was found that the least risk of pain emergence after endodontic treatment occurs with tooth canal widening by CrownDown technique because in this case the minimal amount of canal preparation products are educted into periodontal tissues.

Adhesive strength of gutta-percha stems connection to the root channel walls was evaluated. The pressure on dental root channel walls during tooth filling by the lateral condensation method was evaluated. The study was carried out on an Instron device by the pulling out method. The study showed that for stems Nos. 15-30 the retention strength in the root channel was about 2-fold higher than for stems Nos. 35-45. The results indicate that the value of stem pressure on root channel walls during tooth filling by the lateral condensation method can be considered critical with regard to the strength of the dental root proper.

Marginal leakage in class I cavities restored with chemically hardened resin composites (Talan, Charisma PPF, Esterfill) and adhesive strength were studied in vitro. The results indicate the least marginal leakage and best adhesive strength of the Talan composite.

Wear resistance parameters were evaluated for 5 materials used for masticatory teeth filling. The study was carried out on an Uism-1 device for evaluation of abrasion resistance of dental materials by the friction method during circular movement of a premolar (removed for orthodontic indications) along the surface of reference material. Similar abrasion resistance in the material-tooth pair was detected for 4 materials: Herculite XRV (Kerr-Sybron), Unirest (Stomadent), Dyract AP (Dentsply/De Trey), and Tytin amalgams (S.S. White); the parameters of wear differed. The highest wear of material paralleled by high tooth abrasion were detected for Filtek P-60 (3M/Dental) material.

200 patients (500 restorations of front teeth) were examined. All the restorations were made of light-curing composite materials (microfills, hybrids, compomers, and combination of microfills and hybrids) from 5 do 9 years ago. Clinical and esthetical parameters were evaluated. We had to replace 96 restorations of 500 (19.2%), only 50 (10%) restorations were marked as "excellent". Direct veneers made of microfilled composite materials showed the best results (30%--"excellent" restorations). The restorations of devital teeth and V-class restorations of compomer material show the worse result (20% restorations replaced).

Comparative colorimetric evaluation of shades and translucency of different samples, fabricated from Filtec Z-250, Unirest, Dyract AP and Vitremer, shows, that differences in their compositions and industrial technologies result to great differences between the shades of the same number of Vita Shade Guide. The less color stability after long term action by foods media to the samples was found for the glass ionomer cement. The best color stability was found for composites, partially, for Unirest. All of these, let us conclude, that the main changes, not only in shades, but in translucency of materials, as a result the action of model media, take place at the early periods (the first month). Usually, the most main changes in restorative materials take place in this period of beginning and connect with the end of setting processes and achieving the balances between water absorption and solubility.

Pressing problems in bleaching devital teeth are discussed. Bleaching Endoperox and Brilliant were studied in vitro. For evaluating the safety of devital teeth bleaching, the microhardness of dental tissues was evaluated after intra-crown bleaching. The most significant changes in microhardness were observed in the coat dentin area.

Presents the indications for the use of autohardening composite materials in dentistry and validates the need in introduction of materials of different classes along with universal hybrid composites. Sums up the results of introduction of these materials into practice and discusses the trends in the practical use of photohardened composites in Russia.

The efficiency of aeroabrasive preparation (AAP) of teeth was evaluated by clinical methods and scanning electron microscopy. The authors conclude that the use of AAP should be confined to the treatment of surface and medium caries. Analgesia before AAP is obligatory, except cases with preparation of fissures for preventive hermetization. The use of AAP is absolutely contraindicated in cases of allergic reactions in the patient, dentist, or assistant. Methods for protection of the dentist, assistant, and patient during the use of AAP are discussed.

The reaction of pulp vessels to various adhesive systems was studied: qualitative and quantitative characteristics of pulse curves reflecting the pulp blood filling were studied. Study of the reaction of pulp vessels showed that acetone-containing adhesive systems immediately caused a constrictive reaction, while use of an acetone-free adhesive system led to the minimum changes in the functions of pulp vessels.

Adhesive strength of combination of several liner and filling materials used for filling dental root channels was studied and the marginal permeability of root channel from the side of the crown was evaluated after filling with several pairs of pad and filling materials. Filling of root channels with gutta percha pins with hermetics did not deteriorate the strength of adhesion of BaseLine pad to the bottom of the cavity, while filling with Forfenane decreased the adhesion of this pad material 3-fold. Use of Belocor polycarboxylate cement for pad essentially deteriorated the adhesive strength of the pad irrespective of the filling material.

The quality of hermetic sealing of the opening of an obturated root channel with various sealing materials (Bezline and Russian material Foscin and Belokor) was studied. Root channels were obturated using Endomethason, Forfenan, and gutta-percha pins with hermetic AN-PLUS. A total of 187 teeth of different groups were filled in patients aged 17-85 years. The quality of hermetic sealing of an obturated root channel was evaluated by x-ray examination and electrometrically directly after filling (in 10 min) and in remote periods (after 6, 12, and 24 months). The best results were attained with Bezline and gutta-percha. A combination of Bezline and Endomethason yielded satisfactory results.