Oxytalan fibre organization in marsupial mandibular periodontal tissues.

The arrangement and distribution of oxytalan fibres in Australian marsupials has not previously been reported. Periodontal tissues of wombat, wallaby, possum, and marsupial mouse were examined to ascertain oxytalan fibre organization. Despite adaptation of the marsupial masticatory apparatus to different diets the oxytalan fibre organization in the periodontal ligament shows a basic pattern which corresponds with that reported in other animals. The oxytalan system forms a continuous meshwork of fine, branching fibres which completely invests each tooth root and connects adjacent teeth. Thick ribbon-like apico-occlusally orientated oxytalan fibres, thought to form by the coalescence of thinner fibres, are restricted to the periodontal ligament. The oxytalan fibres are embedded in cementum and attached to blood vessels in the pariodontal ligament. Oxytalan fibres do not insert into alveolar bone. Histological evidence indicates functional remodelling of the oxytalan fibre system in continuously erupting teeth.