Effect of selenium on developing mouse teeth in culture in vitro.

First molars from 2-day-old mice were cultured for 7 days in medium supplemented with 0.04, 0.4, 4.0 parts/10(6) selenium (Se) or 10 per cent calf serum. Collagen synthesis, measured after labelling with [3H]-proline for the last 24 h of culture, was most active at 0.4 parts/10(6) Se. Supplementation with 300 parts/10(6) Se for the first 24 h of culture caused ultrastructural changes in newly-deposited enamel and dentine matrices.