A review on Success and Failure in endodontic treatment

Points from ingle• 5 year study conducted by the University of Washington-

patients recalled at 6 months, 1,2,5 years.• Success/failure evaluated mainly by radiographic

assessment at recall time.• Success-teeth that demonstrated decided periradicular

improvement and those with continuing periradicular health.

• Failure – those teeth that initially demonstrated periradicular damage and that had not improved, as well as those that had deteriorated since treatment.

• Results at 2 year recall were discussed-total 3678 patients, 1229 at 2 year recall

• 104 failures reported.

Failure in Washington study:– 13 causes, subdivided into 3 groups:

• Apical percolation• Operative error• Errors in case selection

• Apical percolation 63.46%– Incomplete obturation– Unfilled canal– Ag point inadvertently removed

• Operative error 14.42%– Root perforation– Canal grossly overfilled or overextended– Broken instrument

• Errors in case selection 22.12%– External root resorption– Coexistent periodontal-periradicular lesion– Developing apical cyst– Adjacent pulpless tooth– Accessory canal overfilled– Constant trauma– Perforation, nasal floor

Distribution of Failures of Treated Endodontic Cases: Two-Year Recall by Frequency of Occurrence

Causes of failure No of failures % failures

Incomplete obturation 61 58.66

Root perforation 10 9.61

External root resorption 8 7.7

Coexistent periodontal-periradicular lesion 6 5.78

Canal grossly overfilled or overextended 4 3.85

Canal left unfilled 3 2.88

Developing apical cyst 3 2.88

Adjacent pulpless tooth 3 2.88

Silver pointinadvertently removed

2 1.92

Broken instrument 1 0.96

Accessory canal unfilled 1 0.96

Constant trauma 1 0.96

Perforation, nasal floor 1 0.96

Total failures 104

Prognosis:1. The more extensive and severe the

endodontic pathosis, the poorer the prognosis.

2. The more dental treatment that is done, the poorer the prognosis. The worst prognosis lies with teeth that have been retreated nonsurgically and then re-treated surgically once or twice more.

• Grossman divided the causes into four categories: – poor diagnosis, poor prognosis, technical difficulties, and

careless treatment.• POOR PAST, (Crump et al DCNA 1979)

– Perforation, – Obturation, – Overfill,– Root canal missed– Periodontal disease, – another tooth, – split,– Trauma," all of which may cause endodontic failure.

Postoperative causes of failure

• Post space preparation and placement• Inadequate restoration• Occlusal trauma and bruxism• Superimposed nonendodontic causes-

orthodontic treatment and periodontal pathology

• Others

Post space preparation and placement

1. Perforation – improper orientation2. Disturbance of remaining obturated material3. Inadequate thickness of obturating material left4. Lateral forces on dentine during post placement-

especially tapered, threaded posts.5. Tapered posts create a wedging effect.6. Post width exceeding 1/3rd of the canal width.7. Absence of ferrule can predispose the crown to fracture8. Delay in post cementation leading to leakage due to a

leaking interim post and artificial crown.

Improper coronal restoration

• Time period between obturation and permanent restoration is long.

• Temporary restoration is left for a long time.• Inadequate thickness of temporary restoration – minimum

3.5mm.• Lack of marginal seal of leading to secondary caries• Tooth is non-vital – any progressing caries does not cause

symptoms and generally remains undetected until clinical examination.

• Margin of the restoration impinging on the biological width – improper cleaning, periodontal pocketing, secondary caries, lack of marginal integrity.

Occlusal trauma and bruxism

• Crown/tooth fracture due to overloading- as abutment for precision attachments, distal extension base RPDs, posterior cantilevered fpd.

• Inadequate coronal restoration• In cases of bruxism, full coverage restorations are

essential(Abou Rass)• Night bruxism intensifies normal pressure 10

times because proprioception is lost in REM sleep.

Superimposed nonendodontic causes

• Orthodontic treatment• Periodontal problems

Other factors

1. Lack of proximal contacts2. Systemic diseases

prevention

1. Long-term followup

• Cases of unresolving post-treatment periapical radiolucencies are commonly referred to as 'endodontic failures'.

• It is generally acknowledged that most failures occur when treatment procedures have not reached a satisfactory standard for the control and elimination of infection.

• Common problems that may lead to endodontic failure include inadequate aseptic control, poor access cavity design, missed canals, inadequate instrumentation, and leaking temporary or permanent fillings (Sundqvist and Figdor, 1998).

references

• An Evaluation of Coronal Microleakage in Endodontically Treated Teeth. Part I. Time Periods JOE vol 13 no2

• Shigeyuki S, Masahiko I, Hiroshi K, et al. Analysis of bruxism occlusal force concerning formation of facet on occlusal splint for estimation of bruxism. Japanese Journal of Conservative Dentistry. 2006;49(1):6-16.

• Restoration of Endodontically Treated Teeth Paul R. Chalifoux, DDS