The aim of the study was to investigate the character of contacts between cells and surface of dental materials used in pediatric dentistry. The materials used Ketac Molar, Fuji II LC, GC Fuji II, Tetric EvoCeram, hybride composite resin of NuSmile crown, Dyract flow, stainless steel (NuSmile crown), Nichrom crown, and Safargam+ non gamma 2 were tested. HeLa cell line was used for the tests. The cells were cultivated in MEM medium containing 10% FCS antibiotics. After 72 hours of cultivation the samples were fixed and processed for investigation in a scanning electron microscope. The growth inhibition test was performed on HeLa line cells. The cell culture growth was observed in Nicon Eclipse TE 200-E microscope for 24 hours and recorded in 2 min. intervals by NIS-Elements AR program. The following results were achieved. Cells of HeLa cell culture continuously covered surfaces of most materials tested except for Safargam+ non gamma 2. The cells were connected to surfaces by large cell processes. The cell surface was irregular, and the cells sent numerous fine projections into their surroundings. Regularly, larger or smaller vesicles and cells in various stages of mitoses were observed. The growth inhibition was recorded only in Safargam+ non gama 2 and stainless steel in the extent that can be considered cytotoxic. In remaining materials a curve, after the incipient cessation, increased steadily. The conclusion is commonly used dental materials are not always fully cytotolerant. Safargam and stainless steel have been found to be even of cytotoxic character. Keywords: pediatric dentistry, cultivation, HeLa-line, cytotoxicity, cytotolerance, dental materials