Apical Extrusion of Debris in Flat-oval Root Canals after Using Different Instrumentation Systems

A. L. Kirchhoff, L. F. Fariniuk, and I. Mello

Journal of Endodontics. 2015 February; 41:237–241.


INTRODUCTION: The purpose of this study was to evaluate the amount of apically extruded debris in flat-oval root canal systems during cleaning and shaping with different instrumentation systems.

METHODS: Seventy-two mandibular incisors were randomly assigned to 4 groups (n = 18) according to the instrumentation system to be used: the ProTaper Next rotary system (PTN; Dentsply Tulsa Dental, Tulsa, OK), the WaveOne reciprocating system (WO, Dentsply Tulsa Dental), the Twisted File Adaptive (TFA; SybronEndo, Orange, CA) rotary/reciprocating system, and the Self-Adjusting File (SAF) system (ReDent-Nova, Ra'anana, Israel). Debris extruded during the instrumentation was collected and dried in preweighed Eppendorf tubes. Three consecutive weights were obtained for each tube, and the average was calculated. The data were analyzed using the t test and analysis of variance (Games-Howell test).

RESULTS: The SAF produced significantly more debris compared with the other systems (P < .05). No significant difference was noted amongst the PTN, WO, and TFA (P > .05).

CONCLUSIONS: Regardless of the instrumentation system used, apical extrusion of debris was exhibited at some level, regardless of the instrumentation system used. The SAF was associated with the highest amount of debris extrusion compared with PTN, WO, and TFA.


The full article is available online: ResearchGate

Kirchhoff extrusion jendod joe


Additional Info

  • ReDent Nova’s note:


    Two elements in this study contradict the authors' statement of conducting the experiment according to manufacturer's directions: Irrigation rate of only 1ml/min, and the use of 31mm files in root canals with an average length of 13mm (attained by personal communication, not detailed in the paper). Those elements led to escaping of the irrigation solution through the 8mm of mesh of the SAF which were out of the canal, and combined with the insufficient flow rate, this must have led to creation of "debris mud" that was likely to be extruded. Such "mud" is never created upon proper use.


    The authors had declined professional advice that was offered to them. Had they used adequate SAFs (21mm) with a 4ml/min irrigation rate, this would lead to different results, as already presented in previous studies of this kind. 


    Also, according to the acknowledgements of the paper, it was financed by the two other device manufacturers.

  • publisher: publisher
  • View abstract on PubMed. PMID: 25447504