ENDO Procedural Complications Flashcards
___ is an artificial irregularity created on the surface of the root canal wall that impedes the placement of instruments to the apex
ledge
what happens to working length when a ledge is formed?
it can no longer be ascertained
radiographically, what might indicated ledge formation?
- instrument or obturation material is short of the apex
- instrument or obturation material no longer follows the true curvature of the root canal
what are 5 reasons ledges occur?
- lack of straight line access
- anatomy of the canal
- inadequate irrigation or lubrication
- excessive enlargement of curved canal with files
- obstruction or the packing of debris in the apical portion of the canal
lack of straight line access can be caused by improper access preparation and can compromise the negotiation of the ___ of a canal through improper ___
apical third, coronal flaring
what components of anatomy of the canal can cause ledge formation?
- length (longer canals; want to recapitulate to confirm patency)
- canal diameter (smaller diameter)
- degree of curvature (greater degree of curvature; BL curvature is difficult to assess given buccal radiographic exposure)
describe how ledges can be avoided with irrigation and lubrication
- NaOCl is a good irrigant for disinfection and removal of debris, but an additional lubricant is necessary
- lubricants allow for ease of file insertion, decrease of stress on instruments, and ease of debris removal
___ is the process where files cut dentin toward the outside of the curvature at the apical portion of the root
transportation
describe how transportation causes ledging
- the transported tip of the file may gouge into the dentin and create a ledge or perforation outside the original curvature of the canal
- each successive file size should be used before a greater sized file is attempted (do not jump sizes)
- flexible files reduce ledge formation
how is ledge formation corrected?
- the canal first must be relocated and renegotiated
- a precurved (1-2mm apically) small file is helpful to reestablish WL (use plenty of lubrication and use a picking motion)
- if true canal is located, use a reaming motion and up-and-down movement to maintain the space and debride the canal
- flaring the access may help improve access to the apical third of the canal
despite all effort, correction of a ledge is difficult because ___
instruments and obturating materials tend to be directed into the ledge
if unable to bypass a ledge, what should you do?
clean and shape at the “new” WL
successful treatment and prognosis after ledge creation depends on ___
- the extend of debris remaining in the region past the ledge
- short and clean apical ledges have better prognoses
during ledge formation, the amount of debris remaining in the region past the ledge depends on what?
when the ledge formation occurred int he cleaning and shaping process
what should you tell your patient if a ledge forms?
inform the pt of the prognosis, and instill the importance of recall and the signs that would indicate failure
what are 3 ways instruments separate?
- limited flexibility and strength of the instrument
- improper use (overuse, excessive force, wrong movement, etc)
- manufacturing defects of instruments causing breakage are rare
what are 5 ways to avoid separating instruments?
- recognize the stress limitations of the instruments being used
- continual lubrication of the instrument within the canal
- examine the instruments to be placed into the canal
- replace files often
- do not proceed to larger files until the smaller ones fit loosely within the canal
before separation, steel instruments often exhibit ___
fluting distortions, highlighting unwound or twisted regions of the file (signs of fatigue)
how do you check for fatigue of nickel-titanium files?
they do not show the same visual signs of fatigue that steel files do, and should therefore be discarded before visual signs occur
how do you treat a canal with a separated instrument?
- bypass the instrument (same principles as bypassing a ledge)
- remove the instrument (usually unsuccessful, and referral to endodontist is necessary)
- prepare and obturate the canal to the point of instrument separation (clean to “new” WL, which corresponds to the coronal most aspect of the separated instrument)
successful treatment and prognosis of a separated instrument depends on ___
- extent of debris remaining in the region below the separated instrument
- prognosis improves if instrument separation occurred during later stages of cleaning and shaping
- prognosis is poor for teeth where smaller instruments have been separated
- overall, if instrument separated is managed properly, the prognosis is favorable
what must you tell your patient if a file separates?
inform the pt and document history of the separated instrument
when instrument separation has occurred, if the pt has residual symptoms, what should you do?
the tooth is best treated surgically (root end resection)
___ is an iatrogenic communication of the tooth with the outside environment
perforation