INVESTIGATION OF STRESS-STRAIN STATE OF "RESTORATION & TOOTH" SYSTEM IN WEDGE-SHAPED DEFECTS BY COMPUTED MODELING METHOD.

OBJECTIVE: The aim of this research is to study the influence of size and location of wedge-shaped defects of teeth on stress and strain state of restorative material on the basis of biomechanical analysis. PATIENTS AND METHODS: Materials and methods: Biomechanical analysis of the stress-strain state was performed on a jaw bone fragment with canine and premolar inclusion. RESULTS: Results: Tangential stress increase both in the adhesive layer and in restorative material with depth and width (medial-distal size) of restored wedge-shaped defects of teeth,.The most unfavorable loading on a tooth is a joint action of vertical and horizontal loading in lingual- vestibular or vestibular-lingual direction, depending on localization of the restored wedge-shaped defects of teeth. The formation of retention grooves in wedge-shaped defects of teeth reduces the value of the maximum tangential stress in the adhesive layer of restorative material to 25% and extends the longevity of restorations. CONCLUSION: Conclusions: The difference in maximal values of tangential stress increases in adhesive layer of restorative material with or without retention grooves with increasing depth of defect. Thus, it is advisable to form retention grooves in cases of wedge-shaped teeth defects that exceed 1.5 mm. In case of restoration of subgingival wedge-shaped defects of teeth of small height it is recommended to create one retention groove on the gingival or incisal planes of a carious cavity due to significant inconveniences, and sometimes impossibility of formation of traditionally located retention grooves.

LABORATORY METHODS OF RESEARCH OF ADHESIVE SYSTEMS.

OBJECTIVE: The aim of out research was to determine the effectiveness of the sealing property of adhesive systems V and VII generations by studying the depth of curing, water absorption and water solubility of their samples. PATIENTS AND METHODS: Materials and methods: The study was performed according to ISO / TS 11405: 2015 at the Central Factory Laboratory of JSC "CTOMA", Kharkiv, Ukraine, Certificate of Attestation No. 100-062 / 2015 dated 03/04/2015. For the study we used specially prepared laboratory samples which were made in the form of plates from adhesive system "DC Adhesive NF" (Dental Central) of V generation "Single bond Universal" (3M ESPE) of VII generation. А monitor and analyze the results obtained used micrometer MK-25, №4694, №03 / 5321 from 08/18/17; caliper SC-1, No. 267447, No. 03/5322 from 08/18/17; scales AP 210, №112144137, №87027 / 9 from 24.11.2017. RESULTS: Results: According to the results of the investigation the following results were obtained: 1) the average curing depth of V and VII generation of adhesive systems was 4.08mm and 3.51mm respectively at the rate of 2mm; 2) average water absorption: 45.97 µg/mm3 and 30.89 µg/mm3 for V and VII generations respectively; 3) the average water solubility was 6.94 µg / mm3 and 4.17 µg / mm3, respectively. CONCLUSION: Conclusions: According to the results of our laboratory studies, it can be concluded that adhesive systems of V and VII generations can be used for restoration of lesions of tooth hard tissued. Along with this, it can be recommended to use V generation adhesives in closed defects where direct polymerization should be performed and oral fluid access is minimal. Adhesive sysyems of VII generation can be recommended in such cases as: opened restorations, pregingival areas of teeth, cases where a permanent contact of restorations with oral fluid be found along with the cases of autonomic application of adhesive system.

Reasoning of adhesive system choice for treatment of patients with increased tooth wear.

OBJECTIVE: Introduction: Perceiving the high prevalence of direct composite restoration technique usage for the rehabilitation of patients with increased tooth wear, as well as during the sanitation of oral cavity before indirect methods of rehabilitation, there is a necessity in more detailed reasoning of adhesive system application for treatment of dentition with increased tooth wear. The aim: The purpose of our work was to study the microstructure and chemical compound of hard tissues of teeth on background of increased tooth wear with the presence of a carious process with the application of adhesive systems of 5th and 7th generation. PATIENTS AND METHODS: Materials and methods: The researche of teeth with physiological and increased tooth wear with the presence of carious process in the amount of 40 pcs. was carried out with the help of a raster electron microscope (SEM) Mira 3 LMU (Tescan, Czech Republic) with a maximum resolution of 1 nm and a maximum increase of 1 000 000. Elemental composition of the local area was determined using the X-max 80mm2 energy dissipation spectrometer ( Oxford Instruments, UK), integrated into a raster electron microscope. RESULTS: Results: The number of enamel prisms per square area in the case of increased tooth wear is 19 per 100 microns on average and 22.65 per 100 microns in carious teeth. CONCLUSION: Conclusions: Greater permeability is observed in the adhesive system of 7th generation (Adper Easy One), which allows it to be recommended for usege in the cases of severe caries and increased tooth wear.

[Morphological study of enamel and dentin teeth with carious process and non-carious lesions].

OBJECTIVE: Introduction: The condition of hard teeth tissues while choosing treatment method becomes particularly important due to the large development of adhesive technologies and the choice of filling materials. The quality of adhesion is one of the key factors that affects effectiveness of the entire range of therapeutic interventions, that determines the success of therapeutic treatment and the reliability of therapeutic restorations fixation. The aim of the work is to study the condition of hard teeth tissues in carious and non-carious pathology for further rationale of the choice of filling material and adhesive system. PATIENTS AND METHODS: Materials and methods: A thorough examination included teeth that were removed according to the indications. The age of patients, whose teeth were examined, was 25-55 years old according to the classification of age periods adopted at the International Symposium on the Age Periodization (Moscow, 1965). We conducted a morphological study of enamel and dentin of teeth with carious and non-carious lesions (increased erasability, cuneal defects), by obtaining chips and microsections of teeth, followed by examination of the number of enamel prisms, dentinal tubules,their diameter, the thickness of the gaps between these structures. The studies were carried out using a scanning electron microscope (SEM) "Mira 3 LMU" ("Tescan", Czech Republic) with a maximum resolution of 1 nm and a maximum magnification of 1,000,000. Dentally removed teeth were washed in running water, cleaned of plaque, dried by filter paper and crushed by vice, that was followed by the selection of the wreckage for the study. Then, markings in the dentine and enamel zones were made to fix the sizes of enamel prisms and dentinal tubules. RESULTS: Results: After the completion of the determination of enamel prisms and dentinal tubules diameter, counting of their number was carried out according to the method proposed by I.M. Tkachenko, by obtaining a series of digital images of the examined tooth's enamel and dentin with varying degrees of magnification. The number of prisms per unit area characterized the enamel density, on which permeability, hardness, tissue resistance to fracture, bending and modulus of elasticity depends. The number of dentinal tubules characterized the density of dentin and the peculiarities of trophic processes that occur in dentin. Also, in our opinion, the amount of dentinal tubules determines the damping properties of dentin and strength enamel values. CONCLUSION: Conclusions: Thus, the structure of enamel and dentin has peculiarities of the morphological structure at various clinical conditions of hard teeth tissues. This peculiarity can be associated with a decrease of enamel density, that is associated with a decrease in the number of prisms in the non-carious teeth pathology and an increase of the gaps between them.

Performance of a redesigned HIV Selectest enzyme-linked immunosorbent assay optimized to minimize vaccine-induced seropositivity in HIV vaccine trial participants.

Vaccine-induced seropositivity (VISP) or seroreactivity (VISR), defined as the reaction of antibodies elicited by HIV vaccines with antigens used in HIV diagnostic immunoassays, can result in reactive assay results for vaccinated but uninfected individuals, with subsequent misclassification of their infection status. The eventual licensure of a vaccine will magnify this issue and calls for the development of mitigating solutions in advance. An immunoassay that discriminates between antibodies elicited by vaccine antigens and those elicited by infection has been developed to address this laboratory testing need. The HIV Selectest is based on consensus and clade-specific HIV peptides that are omitted in many HIV vaccine constructs. The assay was redesigned to enhance performance across worldwide clades and to simplify routine use via a standard kit format. The redesigned assay was evaluated with sera from vaccine trial participants, HIV-infected and uninfected individuals, and healthy controls. The HIV Selectest exhibited specificities of 99.5% with sera from uninfected recipients of 6 different HIV vaccines and 100% with sera from normal donors, while detecting HIV-1 infections, including intercurrent infections, with 95 to 100% sensitivity depending on the clade, with the highest sensitivities for clades A and C. HIV Selectest sensitivity decreased in very early seroconversion specimens, which possibly explains the slightly lower sensitivity observed for asymptomatic blood donors than for clinical HIV cases. Thus, the HIV Selectest provides a new laboratory tool for use in vaccine settings to distinguish the immune response to HIV vaccine antigens from that due to true infection.

Serologic diagnosis of human Taenia solium cysticercosis by using recombinant and synthetic antigens in QuickELISA™.

Diagnosis of Taenia solium cysticercosis is an important component in the control and elimination of cysticercosis and taeniasis. New detection assays using recombinant and synthetic antigens originating from the lentil lectin-purified glycoproteins (LLGPs) of T. solium cysticerci were developed in a QuickELISA™ format. We analyzed a panel of 474 serum samples composed of 108 serum samples from donors with two or more viable cysts, 252 serum samples from persons with other parasitic infections, and 114 serum samples from persons with no documented illnesses. The sensitivities and specificities of T24H QuickELISA™, GP50 QuickELISA™, and Ts18var1 QuickELISA™ were 96.3% and 99.2%, 93.5% and 98.6%, and 89.8% and 96.4%, respectively, for detecting cases with multiple, viable cysts. T24H QuickELISA™ performs best among the three assays, and has sensitivity and specificity values comparable to those of the LLGP enzyme-linked immunosorbent blot. The QuickELISA™ are simple, rapid quantitative methods for detecting antibodies specific for T. solium cysticerci antigens.

Development and evaluation of porcine cysticercosis QuickELISA in Triturus EIA analyzer.

We evaluated three diagnostic antigens (recombinant GP50, recombinant T24H, and synthetic Ts18var1) for cysticercosis and found that all three performed well in detecting cysticercosis in humans and pigs in several assay formats. These antigens were adapted to a new antibody detection format (QuickELISA). With one single incubation step which involves all reactants except the enzyme substrate, the QuickELISA is particularly suited for automation. We formatted the QuickELISA for the Triturus EIA analyzer for testing large numbers of samples. We found that in QuickELISA formats rGP50 and rT24H have better sensitivity and specificity than sTs18var1 for detecting porcine cysticercosis.

Validation of sonic boom propagation codes using SR-71 flight test data.

The results of two sonic boom propagation codes, ZEPHYRUS (NASA) and BOOM (TsAGI), are compared with SR-71 flight test data from 1995. Options available in the computational codes are described briefly. Special processing methods are described which were applied to the experimental data. A method to transform experimental data at close ranges to the supersonic aircraft into initial data required by the codes was developed; it is applicable at any flight regime. Data are compared in near-, mid-, and far fields. The far-field observation aircraft recorded both direct and reflected waves. Comparison of computed and measured results shows good agreement with peak pressure, duration, and wave shape for direct waves, thus validating the computational codes.