[Behavior of embryonic mouse teeth in vitro: preservation of the crown pattern and mineralization]

First mandibular embryonic mouse molars (day 18) were cultured for 8 days. Maintenance of crown pattern and amelogenesis were studied in function of different culture conditions. Grown on top of semi-solid coagulum (composed of cock plasma, embryonic extract, fetal calf serum and MEM or BGjb) the typical crown pattern was always conserved. Amelogenesis existed in 85% if the coagulum was composed of 60% BGjb, 30% plasma, 10% embryonic extract and 180 microgram/ml ascorbic acid. Embryonic extract did not inhibit the mineralization. Grown on Millipore filter in the presence of different media (MEM or BGJb supplemented with serum, embryonic extract and ascorbic acid) the crown pattern was always disturbed. Nevertheless amelogenesis was generally initiated. In absence of serum and embryonic extract, chemically defined media (MEM or BGjb, supplemented with glutamine, glycine and ascorbic acid) allowed functional differentiation of odontoblasts and polarization of ameloblasts. These cells did not secrete enamel. If these defined media were devoid of ascorbic acid, predentin was secreted but necrosis of dental papilla cells was observed.