NON SURGICAL ROOT CANAL RE-TREATMENT TECHNIQUES

Nonsurgical root canal retreatment

Indications 

(a)Continued periradicular pathosis

(b) Radiographic evidence of a deficiency in the quality of the root canal obturations

(c) Persistent symptoms

(d) Anticipated restorative or prosthetic procedures will compromise any preexisting root canal obturations

conservative re-treatment, apical surgery, and extraction

Retreatment techniques

1. Retreatment of Pastes and Cements 
2. A) Soft-setting pastes– instrumentation + copious irrigation can remove the paste
3. B) Hard-setting cements– Should be dissolved OR
4. i) Dispersion by Ultrasonic Vibration
5. ii) Drilling with Rotary Instruments-

1. II) Retreatment of gutta-percha
2. A) Techniques for Dissolving Gutta-Percha 

1) Solvents of gutta-percha- chloroform, methylchloroform,

2) Hand Instrumentation – canal negotiated with files or reamers to the desired WL

3) Automated Instrumentation

4) Ultrasonic Instrumentation- does not help much 

1. B) Solid Gutta-Percha Techniques 
2. i) Pulling out gutta-percha- Reamers or Kfiles are used to bypass the obturation, and Hedstrom files are engaged into the loosely condensed gutta-percha cones, which are then retrieved in one piece by pulling back the instrument.
3. ii) Rotary removal of gutta-percha-safe only in straight canals.

III. Retreatment of Solid Objects

1. A) Bypassing with hand instruments- Reamers and files may be used to bypass an obstructing object in the root canal, and solvents can be used to soften its cementation.
2. B) Bypassing with automated and ultrasonic instruments- Silver cones that cannot be bypassed with hand files may be bypassed and subsequently retrieved by the Canal Finder.