PRE-OPERATIVE CAUSES OF ENDODONTIC FAILURES

Causes of endodontic failures

Preoperative causes

Problems	Recognition	Correction
1) Incorrect diagnosis – result of misdiagnosis, poor case selection, & poor prognosis	• RCT is done on the wrong tooth, will know during re- evaluation of a patient who continues to have symptoms after treatment	• Treating the wrong tooth includes appropriate treatment of both teeth (tooth incorrectly opened and tooth with original pulpal problem.
2) Altered canal space -pulp stone	• Due to inflammatory response to caries, calcification occur in root canal	• Decalcification by chelating agent (EDTA)
3) Traumatic injuries	• RCT of traumatic tooth has higher failure
4) Internal resorption		• Overextension of the filling must be avoided by creating stop in the dentin short of radiograph apex.
5) Anatomical Variations	• Presence of excessively curved canal, excessive root mineralization impenetrable accessory canal
6) Access cavity	•Underextended often causes debris & the bacteria in the pulp horns to remain	•Make sure roof is completely removed
7) Missed Canal	• During instrumentation, canal is not in the exact centre, indicating that another canal is present	• Retreatment • If fail, only surgical correction.
8) Inadequate debridement
9) Separated instruments -occurs due to limited flexibility and strength of instruments with improper use	• Upon removing file,got blunt tip • Subsequent loss of patency to WL.	• Use special fine diamond tips to create a tunnel and then ultrasonic fine instruments to loosen and flush out broken fragments • Bypass file • Surgical endodontics
10) Canal Blockage -due to files compacting debris at apex	• When WL is shorter	• Recapitulation. Start with the smallest file used, and use quarter turn technique + chelating agent.
11)Excessive haemorrhage -due to extirpation of an inflamed pulp -over instrumentation beyond apex, causing hematoma. → if not resorbed by macrophage, can act as nidus for bacteria growth
12) Underextended filling		•Retreatment is the first consideration
13) Over extended filling. -X determine exact location of AF and absence of apical stop or constriction in mature teeth. -Incorrect selecting of master cone -open apices.
14) Mechanical perforation a) Furcation perforation – Failing to measure occlusal-furcal distance -Inadequate access b) Mid-root & apical third perforation	•Presence of leakage: either saliva or NaOCl into the mouth,unpleasant taste. • complains of pain during tx •A paper point inserted to the apex will confirm a suspected apical perforation	•repair by MTA • sectioning of the tooth or root removal required •repair with MTA if small •If large, apicectomy needed
15)Vertical Root Fracture	•Sudden crunching sound + pain during lateral compaction of GP	•Avoid over preparation of the canal •Use of a passive • less forceful obturation technique and seating of posts.
16)Tissue Emphysema -a blast of air to dry a canal -exhaust air from highspeed drill directed toward the tissue	•rapid swelling, erythema and crepitus	•palliative care and observation to immediate medical attention if the airway or mediastinum is compromised.