Sister-chromatid exchange, chromosomal aberrations and delays in cell-cycle kinetics in human lymphocytes induced by dental composite resin eluates

Abstract

We have investigated eluates derived from commercially available composite resin-based materials used for direct (Tetric Ceram/Ivoclar-Vivadent, Simile/Pentron, Filtek Z-250/3M ESPE) and indirect (Adoro/Ivoclar-Vivadent and Conquest Sculpture/Pentron) dental restorations, with respect to their genotoxic effects on human peripheral lymphocytes. Primary lymphocyte cultures obtained from blood samples of three healthy donors were exposed to eluates of freshly cured specimens of all the materials tested. Metaphases were induced with phytohaemagglutinin, collected after a 72-h treatment using colchicine and stained with the Fluorescence Plus Giemsa (FPG) procedure. Preparations were scored for sister-chromatid exchange (SCE) and chromosomal aberrations (CAs). The proliferation rate index (PRI) and the mitotic index (MI) were also calculated. Our results show that eluates derived from the three direct composites (Filtek Z-250, Simile and Tetric Ceram) increased the frequencies of SCE and CAs and markedly reduced PRI and MI. Tetric Ceram's eluate, being the most genotoxic of all eluates tested, increased the frequencies of SCE up to 24.40 per cell (control, 9.87 per cell) and of CAs up to 424 per 100 metaphases scored (control, 5). Moreover, it caused a pronounced decrease of the PRI down to 1.31 (control, 2.44) and of the MI down to 9.8‰ (control, 19.2‰). In contrast, eluates derived from the laboratory-processed composites (Adoro and Conquest Sculpture) induced much less cytogenetic damage. Overall, the degree of genotoxicity and cytotoxicity decreased as follows: Tetric Ceram > Filtek Z-250 > Simile > Adoro = Conquest Sculpture. These results indicate that composite resins used for direct and indirect dental restorations differ extensively in their cytotoxic and genotoxic potential and in their ability to affect chromosomal integrity, cell-cycle progression, DNA replication and repair. This underlines the impact of improved polymerization with respect to their biological behavior.