Metabolism Of L929 Cells After Contact With Acrylic Resins. Part 2: Soft Relines

Objective: The aim of this study was evaluating the cytotoxicity of resilient relining materials used in Brazil, according to the time of water storage and heat treatment.
Material and Methods: The specimens were made measuring 14 mm in diameter and 1.2 mm thick. Twelve samples of each material were prepared and divided into four groups (n = 3): Group 1: assessment of cytotoxicity immediately after
the samples making; Group 2: assessment of cytotoxicity after storage of the samples in distilled water at 37° C for 24 hours; Group 3: assessment of cytotoxicity after storage of the samples in distilled water at 37° C for 48 hours; Group 4: cytotoxicity after soaking the samples in water at 55° C for 10 minutes. To prepare the extracts, 3 samples of each group were placed into vials containing 3 mL of culture medium and stored at 37° C for 24 hours. L929 cells were used and the MTT test was performed. The results were subjected to two-factor factorial analysis of variance (ANOVA) at the level of 5% significance. In addition, the materials were classified according to the cytotoxic effect: non-cytotoxic, slightly cytotoxic, moderately cytotoxic, and strongly cytotoxic.
Results: The Dentuflex reliner was considered slightly cytotoxic. The other resins, compared to the control group, were classified as non-cytotoxic. Storage in water for 24 or 48 hours did not affect the cytotoxicity of lining materials tested.
Conclusion: The heat-treatment reduced the number of viable cells, and Soft Comfort and Dentuflex resins were classified as slightly and moderately cytotoxic, respectively.