title: [Root fragments of deciduous teeth remaining in the alveolar bone. Microradiographic and ultrastructural study].
abstract: Deciduous tooth fragments retained in the alveolar bone can be either unresorbed portions of root, or root splinters of various sizes resulting from a fracture. The composition and ultrastructure of the fragment dentine remain unchanged even after a long period of inclusion; any specific alterations present at the time of inclusion persist. Some fracture surfaces and resorption lacunae of completely embedded fragments are covered with newly-formed cementum, usually in continuity with the preexisting cementum. Osteo-dentinal ankylosis occurs on certain resorption surfaces. The ultrastructure of the ankylosis zones is characterized by the continuity of the collagenous fibrillar framework of the dentine and that of the newly-formed bone, and by the penetration of bone substance into the dentinal tubuli and the pulp canals.
mesh_terms: D000293:Adolescent; D000328:Adult; D000539:Alveolar Process / Q000033:anatomy & histology / Q000648:ultrastructure*; D003739:Dental Cementum / Q000033:anatomy & histology / Q000648:ultrastructure; D003804:Dentin / Q000033:anatomy & histology / Q000648:ultrastructure; D005260:Female; D006801:Humans; D008297:Male; D008852:Microradiography; D014092:Tooth Root / Q000033:anatomy & histology / Q000648:ultrastructure*; D014094:Tooth, Deciduous / Q000033:anatomy & histology*
vernacular_title: Fragments radiculaires déciduaux inclus dans l'os alvéolaire. Etude microradiographique et ultrastructurale