The development of the periodontal ligament with special reference to collagen fibre ontogeny.

The development of the periodontal ligament was investigated from serial sections of the mandibles of ferrets ranging in age from 42 days to 66 days post partum. Both succedaneous and non-succedaneous teeth were studied and similarities were seen in both types of tooth. No significant amounts of alveolar bone were observed being deposited beneath the erupting root apices and periodontal collagen fibres were seen attached to the walls of the sockets just prior to emergence of the crown into the oral cavity. Compared with the condition a few days after eruption, the collagen fibres on, and just prior to, emergence were thinner, had a more limited area of attachment, and were more randomly orientated. The results indicate that alveolar bone deposition and collagen traction do not generate the eruptive force and that there are species differences in these structural features during the eruptive process.