Genotoxic effect of formocresol pulp therapy of deciduous teeth

To investigate whether formocresol, in Buckley's original formulation, used for pulp therapy of deciduous teeth, can have a genotoxic effect. Genotoxicity was tested in lymphocyte cultures from the peripheral blood of children aged 5-10 y, in Recife, Pernambuco, Brazil. This was a case-control study. The sample comprised 40 children who had primary teeth with non-vital pulps. Two venous blood samples (6-8 ml) were collected from each child, the first prior to pulp therapy (control group) and the second 24 h after pulp therapy (experimental group). Lymphocyte cultures were grown in 78% RPMI 1640 medium, 20% fetal bovine serum, 2% phytohemagglutinin. The lymphocytes were assessed for chromosomal aberrations; each sample involved analysis of 100 metaphases. There was a statistically significant difference between the control and treated groups for the isochromatid gap (p < 0.001), chromatid break (p < 0.009), isochromatid break (p < 0.046), other chromosomal alterations (p < 0.001), and for total aberrations. In view of these results, caution in the use of formocresol in pediatric dentistry is recommended.