Research has shown that most canal preparation techniques lead to the extrusion of debris through the apical foramen. This is removed by the normal body defence systems, although a certain amount of inflammation will result. Concern has been expressed by some authorities that such debris may remain in the apical constriction, and may contribute to failure, particularly if it harbours microorganisms.
The technique of patency filing involves passively inserting a small file, size 08 or 10, 2 mm beyond the established working length. No attempt is made to instrument the foramen, merely to keep it open or patent by deliberately extruding the debris into the periradicular tissues.
The technique of patency filing involves passively inserting a small file, size 08 or 10, 2 mm beyond the established working length. No attempt is made to instrument the foramen, merely to keep it open or patent by deliberately extruding the debris into the periradicular tissues.
The literature on patency filing is at present quite equivocal. No research workers have been able to show either a decrease or an increase in post-operative symptoms or case prognosis. The technique remains subjective and subject to the operator s personal philosophy.