Tornado Effect—Ultimate Apically Extruded Fragment Retrieval Technique

ABSTRACT

Separation of instruments can occur during routine endodontic treatment in the canal, thereby preventing thorough cleaning and shaping. The success rate of fractured instrument retrieval mainly depends on three factors 1. length of the instrument, 2. inclination of the canal, and 3. size of the fractured instrument. Many advanced techniques and methods can be used to recover the separated instruments but these techniques may not be suitable in all clinical situations one such scenario is extruded fragment (File or GP) beyond the apex where the availability of cutting-edge equipment is needed, this article emphasizes on understanding the various factors that contribute to extruded instrument retrieval and its outcome, on the other hand, also focuses on different instrumental techniques for retrieving extruded files over the apex.

INTRODUCTION

One of the nightmares during endodontic procedures is file separation it could be more troublesome when the separation happens beyond apex. This could be very challenging to clinicians to retrieve. In many scenarios, the only outcome of this situation could be extraction of the teeth. The incidence of file fractures ranges from 2 to 6%.[1] However, the maximum amount of file fractures reported in NiTi instruments (66%–91%) due to cyclic fatigue and torsional stress.[2]

Besides, so many advancements had been developed in file metallurgy still we lack to overcome cyclic and torsional stress. It is easy and important to prevent file fracture in the canals rather than retrieving the fragment. The files made using M wire technology (thermally treated NiTi) have good physiology and mechanical properties like increased flexibility and higher resistance when compared to conventional NiTi files.[3] The research by Gundogar and Ozyurek, (2017)[4] that Hyflex EDM files (Coltene) in the martensitic face at body temperature had a higher cyclic fatigue resistance compared with Reciproc (VDW) blue and wave one (Dentsply Maillefer) files manufacturer from M wire technology in the austenitic phase. This could convey that Hyflex EDM files have higher austenitic transformation than reciprocal and wave one files.

Regardless the instrument fractures can occur even in thermally treated NiTi instruments if they are made up of metal. One of the difficult and challenging categories in instrument retrieval is retrieving the extruded fragment from the periapical tissues, in such cases either the fragment in the periapical tissues is retained or the tooth is sacrificed for extraction, there are only two techniques of retrieval for such clinical scenarios by Terauchi Y et al. (2022)[5] which are as follows: Instrument retrieval protocol using the XP Endo Finisher, Fragment (File or GP) retrieval protocol using ProUltra PiezoFlow.

EXTRUDED INSTRUMENT RETRIEVAL USING XP ENDO FINISHER

XP endo finisher system is a different Rotary system produced by FKG alloy, with novel heat-treated Max wire alloy (Martensite–Austenite–Electropolish–Flex) which changes its Physiology once it exposed to canal temperature. It has high flexibility, and it’s mainly used to debride the canal anatomy by scrapping the irregularities on the walls, it can easily adapt to the three-dimensional anatomy. The file has the tendency to change to spoon morphology after exposing to intracanal temperature following transforming to austenitic phase. The XP endo finisher can effectively remove the smear layer and intracanal medicaments from the root canals within the apical 3^rd.

The main advantage of XP finisher is when rotated at high speed in clockwise direction can facilitate a Whirlpool or a Tornado effect which is helpful in absorbing the extruded fragments from the periapical tissue into the main canal furthermore which can be retrieved easily. Another advantage of Tornado by XP finisher is that the apical debris is absorbed coronally which in turn facilitates apical healing.[6]

CASE REPORT

A 34-year-old patient had been referred to our center with continuous pain in the lower left second molar, and on clinical examination, the tooth was tender on percussion. Radiographic examination shows mid-bifurcation of mesial roots with 4 mm divergent fracture instrument in mesiolingual canal along with different portals of exists. Upon both examinations, we diagnosed the tooth as irreversible pulpitis with fractured instrument [Figure 1a].

Figure 1.

(a) Preoperative radiograph showing fractured instrument, (b) E88 tip troughing in the inner wall up to 90°, (c) E88 tip troughing in the inner wall up to 180°, (d) Extruded fragment beyond apex

The tooth was isolated with rubber dam and modified coronal access was prepared with start X no. 2 tip (Dentsply). 5.25% NaoCl was used to remove debris. Working length was determined using J Morita apex locator and canals were minimally prepared using Orodeka RC one file system. The mesiolingual canal was scouted, and orifice was prepared for instrument troughing. Once the fragment was visible, ultrasonic troughing was done by E88 tip from inner wall 90° to greater than 180° [Figure 1b and c].

After circumferential troughing the file started to wiggle, to facilitate retrieval 17% EDTA solution was placed in the canal and E88 tip activation was done at piezopower 2 for 20 seconds in up and down motion. However, we could retrieve the second half of fragment, upon radiographic inspection secondary fracture of the first fragment was encountered and the 2.4 mm fragment was sucked into the surrounding periapical tissues 2 mm away from apex [Figure 1d].

Such scenarios can happen in file retrieval very commonly, and further we decided to change the protocol to non-ultrasonic techniques using XPF files. Thorough irrigation and activation were done with 40% citric acid and 5.25% NaoCl respectively to remove smear layer and debris in the canal. Proper saline irrigation was done, and XPF files were placed in canal and rotated at 2500 rpm in pulsating motion just 1 mm beyond the apex for 20 seconds, successfully creating a Tornado and the file popped back into the canal [Figure 2a]. Continuous irrigation was done in all the canals, and canals were completely dried and proceeded for obturation. C Root Strontium-based bioceramic sealer was placed in the canals, and final obturation was done C Root Strontium-based bioceramic putty material [Figure 2b]; postend restoration was done by warm 3M composites [Figure 2c].

Figure 2.

(a) Successful retrieval of extruded fragment, (b) C Root Strontium-Based Bioceramic Putty Obturation, (c) Post-endo done by 3M warm composites

DISCUSSION

Besides modern advancements and improvements of metallurgy in file systems still we face instrument separations in the root canals quite frequently. Instrument separations hinder the process of cleaning and shaping of canal anatomy, thereby compromising the prognosis of the root canal treatment. The prognosis of the tooth depends on several factors like vital or non-vital, canal anatomy, pulp pathology, periapical status, size of fragment, location of fragment and length of the fragment. Besides numerous advances in retrieval systems globally, still we couldn’t overcome all types of clinical scenarios. One such is extruded file fragments over the apex, many clinicians face a numb block when they come across such clinical conditions and opt for orthograde filling retaining the fragment or if they are skilled, they would prefer retrograde surgical procedures but the majority of them prefer extraction procedures completely removing the sound tooth.[1,5]

Nonvisible instrument retrievals are very challenging and require special skills and implementing a proper technique helps to gain success. Extruded fragment retrieval situations are easily achieved by XP finisher files at required rpm. XPF has peculiar wave design which changes to spoon shape (austenitic phase) after exposure to canal temperature. This is the feature facilitating the Tornado motion in the canal which makes the retrieval predictable.

Another method of retrieving extruded fragments is by ProUltra PeizoFlow. This is a continuous ultrasonic irrigation method used in combinations with XPF method; here the Tornado motion is facilitated by XPF beyond the apex once the file is sucked into the canal. The PeizoFlow is activated for retrieval furthermore, and alone PeizoFlow is also used as a retrieval method for extruded fragments. However, one must consider the advent of NiTi instruments, and the file fractures can happen more frequently in the hands of inexperienced clinicians. Proper skills should be attained along with adapting to newer techniques and guidelines to reduce the incidence of file fractures and establish a harmony in the root canal procedures.[1,5,7]

CONCLUSION

XPF file alone and in combination with PiezoFlow ultrasonic tip effectively manage in retrieving the fractured fragments beyond apical regions, but this type of clinical case requires a lot of knowledge on how to implement the technique and should also attain good handwork skills to achieve success.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.