Genotoxicity assessment of biphasic calcium phosphate of modified porosity on human dental pulp cells using Ames and Comet assays

Biphasic Calcium Phosphate (BCP) with a ratio of 20/80 Hydroxyapatite (HA)/Beta-tricalcium phosphate (β-TCP) promotes the differentiation of human dental pulp cells (HDPCs). In the current study, the genotoxicity of locally produced BCP of modified porosity (65%) with a mean pore size of 300 micrometer (μm) was assessed using Comet and Ames assays. HDPCs were treated with BCP extract at three different inhibitory concentrations which were obtained based on cytotoxicity test conducted with concurrent negative and positive controls. The tail moment of HDPCs treated with BCP extract at all three concentrations showed no significant difference compared to negative control (p > 0.05), indicating that BCP did not induce DNA damage to HDPCs. The BCP was evaluated using five tester strains of Salmonella typhimurium TA98, TA100, TA102, TA1537 and TA1538. Each strain was incubated with BCP extract with five different concentrations in the presence and absence of metabolic activation system (S9) mix. Concurrently, negative and positive controls were included. The average number of revertant colonies per plate treated with the BCP extract was less than double as compared to the number of revertant colonies in negative control plate and no dose-related increase was observed. Results from both assays suggested that the BCP of modified porosity did not exhibit any genotoxic effect under the present test conditions.