Managing root canal failure Flashcards
what are the different definitions of successful endodontic treatment ?
- strict criteria 1956 = after RCT the PA architecture should return back to normal - difficult as it take a while to return eg. 4yr period
- loose criteria 1993 = tooth functional and asymptomatic, no sinus present and legion radiographically is resolving
- survival 2004 = is tooth still there, easy to measure = binary choice - doesn’t take into account if tooth is functional
- failure = persistence of disease
how do we diagnose failure ?
- Periapical lesions not always visible radiographically until cortical plate penetrated (Seltzer and Bender)
- Large lesion may be present without overt radiographic signs esp in lower molar region where theres thick cortical bone
- Symptoms can be mixed, if present = we can’t just use symptoms to diagnose
how can we overcome the weaknesses of conventional radiography ?
CBCT
Need to consider dose – if conventional film gives you the answer do you need a CBCT
Likely to become a normal part of endodontic diagnosis in the future
why do RC’s fail?
- presents of bacteria in canals
- intraradicullar can still be present = have to look at surgery in these cases
- case reports of more esoteric causes
- Siqueira (2014) states that most common cause for failure is treatment that does not conform to accepted standards
- Persistent versus Emergent disease
- presistance = RCT not good enough to decontaminate canal and persistent biofilm flares up
- emergent = RCT leaked due to poor seal biofilm now gone into RC and disease has emerged
failure summary ?
Generally the RCT hasn’t been done properly
Might look pretty, doesn’t mean it’s been done right
Missed canals are very common
how do we tx plan
- arrive at accurate diagnosis ie. is it a cyst, fracture, PA disease
- Consider options – non-surgical retreatment (redo), retreatment (remove the cyst or granuloma etc) , extraction with or without prosthodontic replacement or monitor
- And write in your notes that you have discussed this
what do we need to look at for non surgical retreatment ?
- restorability assessment
ie. how restorable is it?
how do we do a restorability assessment ?
- First part of endodontic procedure should always be a restorability assessment
- how much tooth structure left
- Cause of much endodontic ‘failure’ is restorative ie tooth fractures or not enough seal
- need to be honest with pt of we can’t do RCT
- Cracks, insufficient dentine, not enough ferrule
- All about vision and illumination
- Literature shows that in order to assess restorability you need to remove existing restorations (Abbott, 2004)
- Not always practical
- If you leave the restoration in, must have consent
- If you are taking the restoration out, must have consent
- Need to visualise final restoration at the start of the treatment plan
what can we use as a guide to assess restorability ?
- restorability index
- Method of assessing remaining dentine and its strategic value
- Splits tooth into segments and gives a score based on tooth structure remaining
- need to take study casts of tooth and give scores to dentine heights = very complex
what are some other refactors we see in restorability ?
- vertical root fracture = contraindication
how do we spot vertical root fractures ?
-Deep but narrow probing defect
-Sinus more coronally (gingival margin) placed than usual – sinus trace radiograph helpful
-‘Halo’ or ‘J-shaped’ bone loss pattern on radiograph
what else do we consider in tx plan?
- cuspal coverage necessary in most posterior teeth
- After reduction for cuspal coverage restoration is there enough dentine left?
- implant vs RCT, what is the most predictable outcome for this patient
when we have made the decision that tooth is restorable what do we need to consider ?
Has it been well treated or not? (bioloigcally and technically)
What is it filled with?
Original anatomy versus damaged anatomy (have we got ledges, perforations etc)
what is apical surgery ?
Direct to surgery not generally the best option unless you know the case
Surgical success rates improve with improved non-surgical root canal treatment
summary for pretreatment planning cases ?
Why did it fail?
Nice white stripes are just that
Restorative failures arguably more common than endodontic failures – can you fix it?
If symptoms persist during retreatment, consider your original diagnosis
