[Tooth grafts in the dog: effect at mid-term of preservation of the periodontal ligament on root and alveolar remnants].

This work was undertaken to study at middle term (5 months) the behaviour of radicular grafts implanted in newly formed sockets. In some of the grafts, the remnants of the periodontal membrane were carefully preserved in a wet medium while in the others the root surface was curetted and dried. Preservation of the periodontal tissues allowed the organization of a periodontal space. This new periodontal ligament was occasionally functional with fibres in continuity from cementum to bone. Generally it was not functional with the fibres laying parallel to cementum and bone surfaces. Early "surface resorption" of the root was prevented as well as ankylosis leading to replacement of root with bone. The extent of ankylosis was reduced. It was localized to the buccal and lingual aspects of the roots where the periodontal ligament was disorganized during the extraction procedure. In the non preserved roots, ankylosis was almost total. Roots were in part replaced with bone. At 5 months, this process was still in progress.