Histological study on the postnatal development and sequence of eruption of the mandibular cheek-teeth of rabbits...

The postnatal development and sequence of eruption of mandibular cheek teeth of rabbits were studied by histological methods. Hemi-mandibles were dissected and sectioned in longitudinal sections of 7 mu and stained with hematoxylin-eosin and Masson's trichrome. The presence of two mandibular deciduous molars which are replaced by corresponding premolars and of three mandibular permanent monofisary molars was confirmed. Eruption of deciduous molars of the mandible begins at 4 days after birth and of the mandibular permanent molars at 9 days, while that of mandibular premolars occurs at 23 days, replacing the mandibular deciduous molars which have exfoliated. At 32 days all the mandibular permanent cheek-teeth are erupted. At birth the mandibular deciduous molars are completely developed and at 4 days their root resorption is initiated. At the first day P3 is in the bell stage and the P4 has begun dentinogenesis. In M1 and M2 amelogenesis is observed.