Cytogenetic Damage Induced in Human Lymphocytes by Dental Composite Resins

Objectives: The aim of this study was to investigate the possible genotoxic and cytotoxic effects of eluates derived from three commercially available, widely used composite resins (Tetric Ceram/ Ivoclar-Vivadent, Simile/ Pentron, Filtek Z-250/3M ESPE) on human peripheral lymphocytes. Methods: Lymphocyte primary cultures obtained from blood samples of three healthy donors were exposed to eluates of freshly cured specimens of all the materials. The elution period of the specimens ranged from 24-72 hours. Metaphases were induced with phytohaemagglutinin, collected after 72 hr treatment, using colchicine and stained by the Fluorescence Plus Giemsa procedure. Preparations were scored for Sister Chromatid Exchanges (SCEs) and Chromosomal Aberrations (CAs). The Proliferation Rate Index (PRI) and Mitotic Index (MI) were also calculated. The study was approved by the Ethical Committee of the Dental School of the Aristotle University of Thessaloniki and all donors willingly signed permissions for using their blood samples for scientific purposes. Results: Eluates derived from all composite materials tested significantly increased the frequencies of SCEs and CAs (p<0.01) and markedly reduced PRI and MI (p<0.01) compared to control untreated cultures. This is indicative of severe genotoxic/mutagenic and cytotoxic activity respectively. This phenomenon was more pronounced as the duration of extraction of the composite resin specimens increased from 24 to 72 hours. The most predominant type of CAs detected were gaps, breaks and acentric fragments, whereas in some cases complete pulverization of nuclear chromosomes was recorded. Overall, the degree of genotoxicity and cytotoxicity decreased as follows: Tetric Ceram>Filtek Z-250>Simile. Conclusion: These results indicate that eluates derived from the composite resins tested can severely affect chromosomal integrity, cell cycle progression, DNA replication and repair. As these materials remain in close contact with the dental and oral tissues, information on their possible genotoxicity and carcinogenicity should be more clearly clarified in the near future.