Effect of oxygen tension on matrix formation and mineralization in hamster molars during development in vitro.

: The effect of 3 oxygen tensions (20%, 50% and 95%) on the pre-eruptive tooth development in vitro was studied biochemically and histologically in 2nd maxillary molars of the hamster. The specific uptakes (uptake per microgram dry weight) of 3H-proline and 45Ca were used as parameters for matrix production and mineralization, respectively. The best results were obtained at 50% O2. Histologically, considerable amounts of predentine, dentine and enamel matrix were found in these molars. Biochemically, appreciable synthesis of matrix and mineralization were measured. In an atmosphere containing 20% O2 less predentine, dentine and enamel matrix were formed. Moreover, production of the matrices occurred in a less regular way. In particular, dentinogenesis in the deeper parts of these molars was affected. The odontoblasts in these areas showed an abnormal and decreased matrix production and eventually dedifferentiated. Biochemically, a lower matrix synthesis and mineralization were measured in these molars.