A micro-computed tomography assessment of the efficacy of rotary and reciprocating techniques for filling material removal in root canal retreatment

Clin Oral Investig. 2016 Nov;20(8):2235-2240. doi: 10.1007/s00784-016-1728-0. Epub 2016 Jan 28.


Objectives: The aim of this study was to compare the efficacy of rotary and reciprocating techniques for removing filling material from root canals, using micro-computed tomography (micro-CT) imaging.

Materials and methods: The distal root canals of 42 human mandibular molars were instrumented with hand files up to size 40 according to a step-down technique and obturated with gutta-percha and an epoxy resin-based sealer using Tagger's hybrid technique. Teeth were divided into six groups (n = 7) according to the instruments used for removal of filling material: group PTUR (Protaper Universal Retreatment), group W40 (WaveOne 40.08), group R40 (Reciproc 40.06), group R50 (Reciproc 50.05), group W25/W40 (WaveOne 25.08/40.08), and group R25/R40/R50 (Reciproc 25.08/40.06/50.05). Teeth were scanned with a micro-CT device before and after use of the instruments to calculate the percentage of remaining filling material. Data were compared using one-way ANOVA and Fisher's LSD test at 5 % significance level.

Results: The mean percentage of remaining filling material was significantly lower when canals were retreated with the set of instruments R25/R40/R50 and single instruments W40 and R50 compared with the set of instruments W25/W40 (P < 0.05), which promoted material compaction in the apical region.

Conclusion: None of the retreatment techniques removed the root fillings completely. PTUR instruments performed equally effective regarding filling removal compared with W40, R40, R50, W25/W40, and R25/R40/R50. For WaveOne, the use of a single instrument (size 40, taper 0.08) was more effective in removing filling material, while for Reciproc showed similar cleaning ability using single instrument or combination of instruments.

Clinical relevance: The results of this in vitro study provide consistent information on filling material removal capacity of mechanized systems during retreatment at the different root canal thirds.

Keywords: Micro-computed tomography; Reciproc; Reciprocating motion; Root canal retreatment; WaveOne.

Publication types

  • Comparative Study

MeSH terms

  • Dental Instruments
  • Humans
  • In Vitro Techniques
  • Mandible
  • Molar / diagnostic imaging*
  • Molar / surgery*
  • Root Canal Filling Materials*
  • Root Canal Obturation / instrumentation
  • Root Canal Obturation / methods*
  • X-Ray Microtomography / methods*


  • Root Canal Filling Materials