[Laboratory assessment of deformational features in thermoplastic materials for removable dentures].

The paper presents the results of laboratory tests of base thermoplastic materials Acry F711 and Flexi N512 in comparison with the traditional acrylic base material Ftoracs to study their deformational properties when loaded by repetitive forces close to the functional chewing loads.

[Laboratory evaluation of tooth whitening agents in hydroxyapatite samples].

The paper presents laboratory model for evaluation of the effectiveness of tooth whitening agents on pure and technical hydroxyapatite (HAP) samples. HAP samples were exposed in distilled water, and colour measurements were taken after coloration in tea extract and using of "Blend-a-med delicate bleaching" ("Procter & Gamble", Germany) toothpaste. The proposed laboratory model allows imitating discoloration by food dye (tea) and measure the whitening toothpaste effect by significant change in colour characteristics in the CIE L*a*b* system.

[Polyurethane denture base material "Pentalur" and modified polyurethane compositions: comparative study of mechanical properties].

Results of laboratory tests of polyurethane based material "Pentalur" conducted to determine its mechanical properties proved the material to meet basic requirements for removable dentures materials. The introduction of simple poluethers with certain molecular weight as well as 1,4-butanediol allows varying polyurethane properties in a fairly wide range. This range of polyurethane mechanical properties along with good biocompatibility opens new possibilities in creation of removable dentures with improved functional properties as well as maxillofacial prosthesis.

[Study of physical-chemical properties ot endodontic sealant Acroseal when different methods of root canal obturation].

Results of the study of physical-chemical properties of new endodontic sealant Acrosil (Septodent, France) were presented. The results of all used in the experiment tests corresponded with the existing standards. The received data were compared with the corresponding tests of endodontic sealant AH-Plus (Dentsply, DeTrey, Germany) and were analyzed statistically. The comparison showed higher adhesion properties of Acrosil.

[Characteristics of domestically produced siloxane elastomer for making elastic gingival prosthetic device].

Gingival prosthetics effectively eliminates esthetic and phonetic disturbances in cases of pronounced gingival recession. Technology for making elastic gingival prosthetic devices of domestically produced siloxane elastomer composition with microwave siloxane vulcanization is described as well as the technique for making combined gingival prosthetics of siloxane composition and colorless plastic.

[Laboratory evaluation of the efficiency of dental root channel filling]. / Otsenka éffektivnosti plombirovaniia kornevykh kanalov zubov v laboratornykh usloviiakh.

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.

[Characteristics of wearing resistance of materials for repair of masticatory teeth]. / Iznosostoikost' materialov, ispol'zuiushchikhsia dlia vosstanovleniia zhevatel'nykh zubov.

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.

[Comparative characteristics of adhesion of chemically hardened composite materials]. / Sravnitel'naia kharakteristika adgezionnykh svoistv kompozitov khimicheskogo otverzhdeniia.

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.

[Potentialities of in vitro evaluation of the efficiency and safety of agents for devitalized tooth bleaching]. / Vozmozhnosti otsenki in vitro éffektivnosti i bezopasnosti sredstv dlia otbelivaniia devital'nykh zubov.

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.

[Comparative in vitro evaluation of color and color stability of composite and ceramic ionomer materials for esthetic repair of teeth]. / Sravnitel'naia otsenka in vitro pokazatelei tsveta i tsvetostabil'nosti kompozitnykh i stekloionomernykh materialov dlia ésteticheskogo vosstanovleniia zubov.

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.

[Special basic material for microwave polymerization of AKR-MV]. / Spetsializirovannyi bazisnyi material dlia mikrovolnovoi polimerizatsii AKR-MV.

Some physical and mechanical properties of the new acrylic material ACR-MW for microwave polymerization, the base material Etacryl-02 ("Stoma", Ukraine) and their analogue Acron MC (GC Lab Technologies Inc., Japan). The findings suggest that the new special denture base material ACR-MW for rapid microwave polymerization (3 min at 100%) possesses the highest bending strength with lower water absorption and solubility. The properties of ACR-MW meet the requirements of ISO 1567.

[Adhesive strength between liner and filling in treatment of root canal: in vitro study]. / Adgezionnaia prochnost' soedineniia prokladochnykh materialov s materialami dlia plombirovaniia kornevykh kanalov zubov: issledovanie in vitro.

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.

[Microwave technology in dental and eye prosthesis]. / Mikrovolnovye tekhnologii v stomatologicheskom i glaznom protezirovanii.

The paper outlines the specific features of using microwave technologies in dental and eye prostheses designed in Russia in 1992-1998. Thermal, microwave, and combined polymerizations of plastic materials used in prosthesis are compared. A Denta microwave unit is presented, which realizes a combined microwave technology.

[The comparative characteristics of chemically and light-hardened composite materials in vitro]. / Sravnitel'naia khrakteristika kompozitnykh materialov khimicheskogo i svetovogo otverzhdeniia in vitro.

The strength and color stability of various composites of photo- and chemical consolidation is assessed by laboratory methods. The class of a material is the most essential factor affecting the above characteristics. The macrofilled and hybrid materials showed the best adhesive and bending strength. The method of consolidation does not notably affect the studied characteristics.