Comparison between Single-file Rotary Systems: Part 1—Efficiency, Effectiveness, and Adverse Effects in Endodontic Retreatment

By Azim A, Wang H, Tarrosh M, Azim K, Piasecki L

Date: 03/2020
Journal: JOE

Purpose: to investigate the ability to use XP for nonsurgical endodontic retreatment and to compare its performance with 2 other single-file systems with regard to the amount of remaining root filling material after retreatment, operation time, and the amount of apically extruded debris after instrumentation

•N = 90 extracted single canal human mandibular incisors

•Excluded teeth with open apices, resorptive defects, caries, root fillings, cracks, calcifications, initial apical diameter > #25, apical curve > 10°

•PA radiographs taken in MD and BL direction and CBCT scans taken

•60 teeth with type I Weine configuration that are similar in length and canal shape and apical diameter were divided into 3 groups (n = 20)

•File systems are:

•Hyflex EDM “one file” (EDM) (Coltene/Whaledent, Alstatten, Switzerland)

•WaveOne Gold (WOG) (Dentsply Sirona, Ballaigues, Switzerland)

•XP Shaper (XP) (FKG, La Chaux de Fonds, Switzerland)

Treatment Procedure:

•Incisal edge flattened to create a reproducible ref poin

•Root canals prepared with Vortex Blue up to size 30/04 and obturated by WV and AH+ sealer then access sealed with cotton and TF. RG taken.

•Each tooth coded and kept in humidity for 30-45 days before retreatment procedure

Re-Treatment Procedure:

•Each group allocated to one of the single file rotary systems (n = 20) 1.WOG group: primary file size 25/07 (reciprocating motion) 2.EDM group: size 25/08 3.XP group: size 27/01

•All procedures done by single endodontist under DOM and tooth/instrument temp maintained

•Once WL achieved, 10 strokes applied followed by visual examination of the canal; if GP present repeat

•Debris were collected and examined

•CBCT scan taken pre-op, after obturation, after removal of GP and after retreatment procedure and remaining RCF material was calculated


•4 samples were excluded

•Sig difference among groups in operating time (XP > EDM > WOG)

•% of remaining RCF material was greater with WOG 25% > EDM > XP

•No diff in amount of extrusion

•When the speed was increased to 3000 rpm, XP was successfully able to penetrate and remove gutta-percha (speed was based on pilot studies)


XP appears to be a suitable instrument for endodontic retreatment when operated at a higher speed (3000 rpm). It was the most efficient in gutta-percha removal from the canals followed by EDM and WOG.