Ledge is an iatrogenically created root canal wall irregularity that may impede placement of an intracanal instrument to the apex.
Treating the wrong tooth
Damage to existing restoration
Access cavity perforations
Cervical canal perforations
Separated instruments and foreign objects
Over- or underextended root canal fillings
Vertical root fracture
Post space perforations
Irrigant related mishaps
Instrument aspiration and ingestion
Improper access prepartion
Compromise the negotiation of the apical third of a canal through improper coronal flaring
Length, Longer canals have a greater potential for ledge, Recapitulate to confirm patency
Canal Diameter, Smaller diameter canals have greater potential for ledge
Degree of curvature, Degree of curvature increases, the potential for ledge increases
NaOCl is a good irrigant, but an additional lubricant is neccessary
Lubricants allow for ease of file insertion, decrease of stress on instruments, and ease of of debris removal
Instruments have the tendency to cut straight ahead and straighten out., Files cut dentin toward the outside of the curvature at the apical portion of the root, a process called transportation.
Transported tip of the file may gouge into the dentin and create a ledge or perforation outside the original curvature of the canal
Don't jump a file size.
radiographic observation with the instrument placed at the point of the suspected ledge
Use plenty of lubrication
Use a picking motion, If the true canal is located, use a reaming motion and occasionally an up-and-down movement to maintain the space and débride the canal
Flaring the access may help improve access to the apical third of the canal
The amount of debris depends on when the ledge formation occurred in the cleaning and shaping process.
Short and cleaned apical ledge have better prognoses