[Indications for the treatment of bone rarefactions of endodontic origin].

Bone rarefactions arising from dental lesions are commonly thought to be sustained by the microbiol component or by the toxins spread out into the surrounding bone by the disintegrated pulp. In thise case endodontic therapy is the only one capable of obtaining a full recovery. In our opinion the most suitable endodontic procedure is that described by Schilder: with his technique infact a great deal of substantial results can be achieved. Bone rarefactions are to be surgically treated only when endodontic therapy does not guarantee the complete removal of microrganisms and that of the tissue debris arising from the disintegrating pulp possibly located in the root's area. This event may occur in the following circumstances: 1) fracture of endodontic instruments; 2) partial filling with cement or any other not removable material; 3) misleading endodontic therapy (distored roads or circular steps); 4) a peculiar anatomy of the dental rost such as that resulting when the apex bears a drop or a trumpet-like appearance; 5) bent roots, very hardly treated; 6) when a dry root's dent cannot be obtained because of the presence of large and continually secreting cysts. Bone rarefactions should then be treated by surgical procedures such as apicectomy backward filling of the root's canal and root's apex locking with direct view of the apex. Apicectomy should only be visualized asd a surgical transport of the apex from a point where the apex is open to an other where is apex is completely filled up by the endodontic treatment. Surgical procedure of the backward filling of the root's canal should be followed only when the root's canal unapproachability does not allow any endodontic treatment such as that suggested by Schilder. Finally surgical procedure to fill up the root's canal with direct view of the apex results from the combination of two surgical treatments: 1) the filling up of the root's canal (Schilder procedure), and 2) the modelling of the root's canal up to a point where the last one is hermetically sealed. This result can be achieved removing the apex when it bears a drop or trumpet-like appearance or the transported apex foramen. It can also be obtained by removing the wounded apex or the radicular canal when it is unapproachable along the 2 or 3 distal mms. and finally ad dry root's canal when it remains wet by the continuous secretion of the liquid material endowed in the cystic cavity.