Inside Dentistry
March 2007
Volume 3, Issue 3

Efficacy of Retreatment Techniques for a Resin-Based Root Canal Obturation Material

Howard E. Strassler, DMD


Resilon/Epiphany obturation system is emerging as an alternative to gutta-percha (GP). The efficacy of retreatment techniques for Resilon removal has not been determined. The purpose of this study was to evaluate two commonly used retreatment techniques in the removal of Resilon. Sixty single-canal teeth were instrumented and obturated with either Resilon/Epiphany or GP/AH Plus. Each canal was randomly allocated to receive one of the two retreatment techniques—ProFile 0.06 rotary files combined with heat or chloroform. The time required to remove the obturation material was recorded and the cleanliness of canal walls was determined by stereomicroscope and electron microscopy. The results demonstrated that chloroform combined with rotary files was more efficient in material removal compared to heat (p < 0.05). Resilon was faster to remove than GP. Both techniques resulted in cleaner canal walls in the apical third of the teeth obturated with Resilon when compared to GP (p < 0.05).


The prognosis for retreatment of unsuccessful, endontically treated teeth by removing the filling in the root canal has depended upon the removal of the root canal filling and reinstrumenting the root canal. Gutta-percha placed with sealers has been the standard of care in the treatment of the root canal even though it has properties that may compromise the success of endodontic therapy, including: poor sealing ability unless used with sealers; risk of leakage when the coronal seal has been compromised; and obturation of the root canal that provides no mechanical benefits to the root. One advantage of gutta-percha that has contributed to its continued use is that removing it from the root canal during retreatment is not difficult. The introduction of the R/E system has provided the endodontist and general dentist with a potentially superior root canal filling system that will provide sealing of the root canal with root reinforcement. One concern often expressed by clinicians is that when non-surgical retreatment of an endodontically treated tooth is indicated, will it be difficult to remove the R/E thermoplastic synthetic resin polymer. Non-surgical retreatment of the root canal can be accomplished with hand instruments, rotary endodontic files and reamers, heat, and chemicals to remove the gutta-percha and sealer, and to clean and shape the root canal. These procedures are effective and clinically predictable. Previous to this study, methods for removing R/E from the root canal had not been evaluated. The researchers of this study compared the removal of R/E to the removal of gutta-percha with ProFile 0.06 rotary files combined with either heat or chloroform. They found that both treatment methods removed the R/E in the root canal within 5 minutes. This retreatment technique took significantly less time when compared to similar techniques using gutta-percha. The ProFile with chloroform technique was the superior technique for root canal filling retreatment with R/E. Also, with both retreatment techniques the authors were able to demonstrate, with the use of microscopy, that the apical walls of the root canal were cleaner after the removal of R/E.

About the Author

Howard E. Strassler, DMD
Professor and Director of Operative Dentistry
Department of Endodontics, Prosthodontics and Operative Dentistry
University of Maryland Dental School, Baltimore, Maryland

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