Fig. 1

Pre-operative radiograph provided by the referring dentist

Fig. 2

Coronal CBCT view of mesial root showing periapical lesion and missed MB 2 canal.

Fig. 3

Coronal CBCT view of distobuccal root showing a slight periapical lesion, and palateal root showing no periapical lesion.

Fig. 4

Magnified view through microscope of MB2 after locating and negotiating.

Fig. 5

Intraoperative working length radiograph showing MB1, MB2 and DB canals. 

Fig. 6

Postoperative radiograph after obturation 

Video of entire procedure 

Fig. 7

About the Author

Dr Hussein Seedat

Hussein Seedat acquired his BDS degree from the University of the Witwatersrand in 1999. He furthered his studies at the University of Pretoria from 2009 onwards where he acquired a postgraduate diploma in endodontics with distinction, an MSc in endodontics, as well as a postgraduate diploma in aesthetic dentistry. 

He has authored and co-authored articles related to endodontics that have been published in the South African Dental Journal, as well as the Journal of Endodontics. He is in private practice in Umhlanga Rocks, Durban, South Africa, where he focuses mainly on Micro-Endodontics, and lectures extensively at congresses and educational programmes on his passion area of endodontics.


Various techniques have been suggested for the removal of Thermafil carriers during endodontic retreatment, some of which have an unpredictable outcome. The use of a lasso technique is proposed as an additional technique to remove the plastic carrier to simplify what is usually considered a challenging procedure.


  1. Bertrand MF, Pellegrino JC, Rocca JP, Klinghofer A, Bolla M. Removal of Thermafil Root Canal Filling Material. J Endod 1997;23:54-57
  2. Torabinejad, Fouad & Walton. Endodontic: Principles and Practice (4th Edition). 2014; Page 374
  3. Wolcott J, Himel VT, DDS, Lamar Hicks M. J Endod 1999. Thermafil Retreatment Using a New "System B“ Technique or a Solvent;25:761-764
  4. Beasley RT, Williamson AE, Justman BC, Qian F.Time Required to Remove GuttaCore, Thermafil Plus, and Thermoplasticized Gutta-percha from Moderately Curved Root Canals with ProTaper Files. J Endod 2013;29:125-128
  5. Rödig T, Wagner J, Wiegand A,Rizk M. Efficacy of the ProTaper retreatment system in removing Thermafil, GuttaCore or vertically compacted gutta-percha from curved root canals assessed by micro-CT. International Endodontic Journal 2018;55:808-815