Cytotoxicity of Acrylic Resins Polymerized by Different Cycles and Methods

Objectives: This study aimed to evaluate the cytotoxicity of N1 acrylic resin for ocular prosthesis, polymerized by different cycles and methods, on human conjunctival cell line. This was accomplished by analyzing the cell proliferation using tetrazolium dye MTT (3-[4,5-dimethylthazol-2yl]-2,5-diphenyl tetrazolium bromide) and Neutral Red assays.
Methods: Ocular prosthesis acrylic resin samples were manufactured and divided into 3 groups, according to the polymerization method (n=3): N1 resin polymerized in water bath (NRWB), polymerized by microwave energy (NRME) or autopolymerized resin (ANR). For each group, different polymerization cycles were evaluated. After the formation of eluates, corresponding to 24 hours of sample immersion in medium, their cytotoxic effect were evaluated using MTT and Neutral Red assays, with Chang conjunctival cells. The eluates were exposed to cells for 24 hours. Data were tested using analysis of variance (ANOVA) with Bonferroni post hoc test (p=0.05).
Results: Regardless of the different cycles tested through MTT assay, autopolymerized acrylic resins exhibited lower cell proliferation percentages, when compared to microwave energy and resin polymerized in water bath. Regarding the Neutral Red assay, it was observed that groups polymerized in water bath showed results similar to the control group.
Conclusions: Resins submitted to different polymerization methods exhibited divergent biological behavior. The autopolymerization resulted in cell proliferation reduction.