Cytotoxicity of two different physical forms of titanium diboride in a in-vitro study

The aim of this study is to investigate the cytotoxicity of titanium diboride (TiB2) ceramic in two physical forms. The cytotoxicity of the chitosan scaffolds, containing TiB2 powder was determined by direct contact test method on periodontal ligament stem cells. Alkaline phosphatase (ALP) enzyme levels in medium were examined on 7th day. TiB2 bulk ceramics produced with spark plasma sintering method (SPS) by using Argon atmosphere under 50mPa pressure at 1800C (Ar-TiB2), vacuum atmosphere under 70mPa 1780C temperature (V70-TiB2) and under 50mPa at 1600C (V50-TiB2) were used. Osteosarcoma cell line (SaOs-2) with normal cell medium was used as control, and cell mediums with extracts were used for cytotoxicity of TiB2 plates. After being kept in cell media for 24 hours, four different dilations of 100%, 50%, 25% and 12,5% extracts were taken from each plates. The cytotoxicity in both forms of TiB2 on 24 h and 48 h were evaluated according to ISO guideline. The scaffolds containing TiB2 powder and chitosan showed no cell viability on measuring by ALP levels. The extracts taken at dilations of 50%, 25% and 12,5% in all plates did not have cytotoxic effect on SaOs-2 in 24 h. V70-TiB2 plate was found to be more cytotoxic on 24 h (p<0.001). Statistical significant differences were found between 12,5% extracts of Ar-TiB2 and V50-TiB2 (p=0.025), and between V70-TiB2 and Ar-TiB2 (p=0.034). After 48 h cell viability was observed to decrease below 70% for all the plates and extracts. Statistical significant differences were found between %12,5 extracts of V70-TiB2 and V50-TiB2 (p=0.015). Negative correlation between the cell viability and material content were found on 24 and 48 h (p<0.001). The cell viability of 100% extracts of all plates on 24 h and 48 h was below 70% and statistically significant difference were found between all plates and their extracts rates (p<0.05). Both powder and bulk plate forms of TiB2 showed cytotoxic effect on cell viability according to ISO guideline. Further studies are needed exposed to temperatures after produced bulk material for evaluating the cytotoxicity. Key Words: titanium diborde, TiB2, titanium, cytotoxicity, ALP.