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

The development and sequence of eruption of the maxillary cheek-teeth of rabbits were studied by histological methods. The presence of three deciduous molars which were replaced by correspondent premolars and of three permanent molars without predecessors was confirmed. The eruption of the maxillary deciduous molars was shown to begin at 4 days postnatally and that of the permanent molar at 9 days, while the eruption of the premolars occurs from 24 days on, replacing the deciduous molars which are exfoliated. The last tooth to erupt is the M3. At 32 days all the permanent cheek-teeth are erupted. The deciduous molars are completely developed at birth, root resorption starting at 4 days. On the first day the premolars are in the bell stage and in the M1 and M2 amelogenesis is taking place. After 27 days the development of the permanent maxillary cheek-teeth is completed. Dentinogenesis, amelogenesis and cementogenesis were observed in all of them.