Cytotoxicity of provisional restoration materials the cell culture tests. Specimens were prepared succinic dehydrogenase activity has been shown between mylor and glass slabs to minimize to be reasonably representative of mitochondrial the oxygen inhibition and maximize the surface activity in the cells and reflects both cell number smoothness. Tempofit Duomix is a two-part base/ and activity.16 The old medium removed and cell catalyst, hand-mix, self-curing and bis-acrylic cultures were rinsed with phosphate buffer composite based provisional restoration material. saline (PBS) and 200 µl aliquots of freshly Base and catalyst were extruded equal amounts by prepared MTT [3-(4,5-dimethyl-thiazol-2-yl)-2,5- pressing onto piston in the dispenser onto mixing diphenyl-tetrazolium bromide, Sigma Aldrich, pad. Both components mixed with spatula within Germany] solution (0.5 mg/mL in BME) were 20 – 30 sec. homogeneously. Then applied into the added to each well. After a 2h incubation period teflon disc and after 2 min – 2 min 30 sec curing (37°C, 5% CO2) the supernatant was removed completed. Protemp 3 Garant is a two-part base/ and the intracellulary stored MTT formazan was catalyst, auto-mix, self-curing and bis-acrylic solubilized in 200 µl dimethyl sulfoxide for 30 composite based provisional restoration material. min at room temperature. The absorbance at Using the Garant dispenser, the base and catalyst 540 nm was spectrophotometrically measured. were extruded directly into the teflon disc and after Twelve replicate cell cultures were exposed to a 2 min 30 sec curing completed. Revotek LC is a constant concentration of a single material in at light cure single component sculptable composite least two independent experiments. The treated resin for temporary restorations. Using a spatula groups compared to cell survival in untreated required amount of material dispensed and applied controls. Differences between mean values were into the teflon disc. The specimen was light-cured statistically analyzed using the Mann-Whitney U for 6 sec by LED light curing unit (LED, Bluephase, test. Ivoclar Vivadent, Liechtenstein, Austria). RESuLtS Four samples prepared for each group for cytotoxicity test. The samples immersed in 7 ml The results of cytotoxicity test with provisional culture medium for 24 hours at 37°C to extract restoration materials are summarized in Figure residual monomer or cytotoxic substances. The 1. Reduced cell density is shown for Tempofit in culture medium containing material extracts were Figure 2(b). In contrast, Protemp 3 Garant group sterile filtered to use on the cell cultures. demonstrate full cell density in Figure 2(c). The results showed that, eluates of the Revotek Cytotoxicity testing LC and Protemp 3 Garant lead to 99% and 101% cell L929 fibroblast cell line (ATCC CCL 1) cultured in survival. Statistically Revotek LC and Protemp 3 Basal Medium Eagle (BME), Biological Industries, Garant were not cytotoxic for cells when compared Israel) containing 10% new born calf serum to control group (P>.05). Eluates from Tempofit (Biochrom AG, Berlin, Germany) and 100 mg/ duomix lead to 88% cell survival. Tempofit duomix ml penicilin/streptomysin (Biological Industries, Israel) at 37°C in a humidified atmosphere of 95% air / 5% CO2. Cell cultures between the twelve and fifteen passages were used in this study. Confluent cells were detached with 0.25% trypsin and seeded at a density of 5×103 well in 96-well plate at 37°C under 5% CO2 for 24h and. After 24 hours incubation, culture medium was replaced with 200 µl of culture medium containing material extracts of provisional restoration materials. Original culture medium was served as control in this study. Cultures were incubated for 24 hours at 37°C and 5% CO2 for 24 hours. The viability of cells exposed to material extracts was assessed using succinic dehydrogenase activity. The Figure 1. Cell survival of L929 cells in a methyltetrazolium test after exposure to provisional restoration materials. Data are expressed as percentage of the control cultures. Cell survival rates were calculated from independent experimental cultures: Control (n=24), Tempofit Duomix (n=24), Protemp 3 Garant (n=24), Revotek LC (n=24). 116 European Journal of Dentistry