Aim and Background: Wide application of nanoparticles in different areas of medical science has been growing faster than before. Small size makes them highly active. Therefore this gives them chemical, physical and biological unique properties. Nanoparticles have no problem crossing through biological barriers in body. Hence, these particles may be utilized in order to target drugs and some other materials. Wide application needs to investigate their cytotoxicity effects on target cells and adjacent cells. In this study we aimed to analysis effect of nanoparticles on INVITRO.Materials and methods: Related articles in this review were obtained from PubMed, Google and Elsevier Science using the key words nanoparticles, cytotoxicity and differentiation.Results: Based on the results of this study, nanoparticles are able to leave both positive and negative effects. In vitro experiments indicate that the main mechanism of action is based on changing levels of intracellular ROS.Conclusion: The results of reported studies have shown that nanoparticles are able to alter intracellular ROS levels and affect growth and differentiation cells.

Background and Aim: One of the most noticeable problems of composite restorations is color change of them over the time Due to this the most important advantage of composites which is providing esthetic is gone, so restorations need to be changed. The purpose of this study is to evaluate the effect of aging on color stability of two types of Bleached shade composites. Materials and methods: In this in vitro study 10 disk shape samples of each two nanohybride composit es DBl XL( IPS Empress Direct, Ivoclar Vivadent, Schaan, Liechtenstein) and Ebl L( IPS Empress Direct, Ivoclar Vivadent, Schaan, Liechtenstein in same size werefabricated. The primary color assessment was done by spectrophotometer matched which CIEI*a*b. Samples were done by the 10000 cycles of aging process which was equal to 1 clinical year. and then had the final test with her spectrometer. The results were evaluated with one way Anova. Results: the color change wasn’ t perceptible( p=0. 136), while the difference in a* parameter between composites was perceptible and DBI was more than EBI. ( p=0. 000) The differences of b and Δ E parametres were not significant for two evaluated composites (p=0. 377 and 0. 136, respectively) Conclusion: . The color change of bleached shade enamel and dentin resin composites after aging was acceptable clinically. (Δ E≥ 3/3).

OBJECTIVE: Keffir is known as one of the sour milk products originated in the north of Caucasus. The antimicrobial and antifungal effects of this product have not already been investicated. In general, keffir contains the following microorganisms: Lactic acid streptococci, lactobacilli, mesophilic lactic acid, lactose fermenting and non-fermenting yeasts and lactic acid bacteria. The objective of this study was to determine therapeutic effects of keffir.METHODS: This study was performed on bacteria such as staphylococcus aureus, E. coli, pseudomonas aeruginosa, salmonella typhi, and three species of fungi: candida albicans, trichophyton mentagrophytes and microsporum canis. The antimicrobial effects of eight extracts of common yoghurt and extract of keffir at 20°c and 37°c at two times of 24 and 48 hour fermentation in vitro on four species of bacteria and three species of fungi were studied by cup plate and serial dilution methods. FINDINGS: From extracts of common and keffir yoghurt at 20°c and 37°c at two times of 24 and 48 hour fermentation, keffir with 75 mg/ml concentration showed the strongest effect on p. aeruginosa at 37°c with 48 hour fermentation time. CONCLUSION: Kerffir has an antimicrobial effect on some pathogenic bacteria as P. aeruginosa.

Purpose: Adhesion to dentin is the major problem in using tooth color composite resins. The way proposed is the use of hydrophile resins, of which, HEMA is the most important one. Because of the importance of the subject, this study was conducted to evaluate the effect of HEMA on shear bond strength of enamel bonding agent to dentinafter I year water storage.Methods & Materials: This INVITRO study carried out experimentally on 36 extracted premolar teeth. The teeth randomly assigned to 4 groups, each group containing 6 samples. In group 1, the solution of %35 HEMA and Acetone and in group 2, the solution of %35 HEMA and Water was used. Multipurpose Scotchbond primer was used in group 4. In group 1 and 2, enamel bonding and in group 4 the adhesive was used. In group 3, teeth were dried and enamel bonded after etching. Composite cylinders were bonded on the areas with the same dimensions.The prepared samples were thermocycled 1000 times at 55°C and 5°C after keeping in distilled water for 1 year. Shear bond strength of the samples were tested by Instron machine.Results: Results showed that the "HEMA and Acetone" group had the highest strength (25.12±3.52), and then, "Scotchbond" group (23.55±1.6)."HEMA and Water" group (14.3±5.6) and "enamel bonding" group (4.25±2.61) had the next ranks respectively. Analysis of variance test showed that the overall difference between them was statistically significant (P<0.0001). Difference in strength of HEMA and Scotchbond was not significant but was significantly different from other groups.Conclusion: Shearbond strength of "HEMA and Acetone" and "HEMA and Scotchbond" became acceptable after thermocycling and storage in distilled water for one year but not in enamel bonding group.