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 Table of Contents  
CASE REPORT
Year : 2019  |  Volume : 31  |  Issue : 1  |  Page : 121-124

Retrieval of separated instrument from the root canal using ultrasonics: Report of three cases


Department of Conservative Dentistry and Endodontics, Faculty of Dental Sciences, SGT University, Gurgaon, Haryana, India

Date of Web Publication19-Jun-2019

Correspondence Address:
Dr. Ashtha Arya
B-8/9, Vijay Park, Najafgarh, New Delhi - 110 043
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/endo.endo_25_18

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  Abstract 

One of the most frequent mishaps during root canal procedure is the separation of an endodontic instrument during biomechanical preparation. It prevents proper debridement of the canal apical to the fragment and compromises the success of the treatment. Development in techniques and armamentarium has led to successful retrieval of separated instrument from the root canal. Adequate knowledge, good clinical skill, and experience enable good management of instrument fractured in the root canal. In this report, we present three cases with separated instruments in the root canal which were successfully retrieved with the use of ultrasonics under magnification.

Keywords: Retrieval, separated instrument, ultrasonics


How to cite this article:
Arya A, Arora A, Thapak G. Retrieval of separated instrument from the root canal using ultrasonics: Report of three cases. Endodontology 2019;31:121-4

How to cite this URL:
Arya A, Arora A, Thapak G. Retrieval of separated instrument from the root canal using ultrasonics: Report of three cases. Endodontology [serial online] 2019 [cited 2019 Nov 12];31:121-4. Available from: http://www.endodontologyonweb.org/text.asp?2019/31/1/121/260523


  Introduction Top


Separation of endodontic instrument in the root canal is one of the most unfortunate occurrences and may impair the success of the root canal procedure. Factors contributing to fracture of endodontic instruments are root canal curvatures, instrument design and manufacturing process, dynamics of instrument use, instrumentation techniques, and operator skill.[1],[2],[3]

Management of separated endodontic instrument includes (a) bypassing the broken fragment, (b) debriding and obturating at the level of separated instrument, and (c) removal of the separated instrument. Various techniques have been suggested to retrieve the separated instrument which includes ultrasonic technique, Masserann kit, and instrument removal system. Studies have shown that use of ultrasonics with magnification has led to high success rate of retrieval of the separated instrument. This report describes three cases in which ultrasonic technique was used to remove fractured instruments from the root canals under magnification.


  Case Reports Top


Case Report 1

A 45-year-old female patient reported in the Department of Conservative Dentistry and Endodontics of our institute with the chief complaint of pain in relation to upper right tooth. She gave a history of root canal treatment with the same tooth at a private clinic, 6 months back and was having pain since then. Clinical examination showed temporary restoration with right maxillary first premolar. The tooth was tender on percussion. Intraoral periapical (IOPA) revealed a fractured instrument at the middle third of the palatal root canal of 14 and the canals were not obturated [Figure 1]a. There was no periapical radiolucency associated with the tooth.
Figure 1: Sequence of fragment removal in case 1. (a) Intraoral periapical showing separated instrument in palatal canal of maxillary first premolar. (b) Ultrasonic tip ET25 used to trephine dentine around separated fragment. (c) Separated instrument retrieved. (d) Intraoral periapical showing fractured instrument removed from palatal canal. (e) Master cone intraoral periapical. (f) Intraoral periapical showing obturated maxillary first premolar

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Retreatment aiming to retrieve the separated instrument was planned, and the patient was explained about the treatment plan and consent obtained. After removal of the temporary restoration access, opening was enlarged. Gates Glidden (GG) drills no. 2 and 3 (Dentsply Maillefer, Ballaigues, Switzerland) were modified by cutting the drill perpendicular to the long axis at the greatest cross-sectional diameter. Modified GG drills were used to prepare a staging platform, and coronal part of the broken instrument was exposed by removing the surrounding dentine. Acteon Satelec P5 neutron ultrasonic generator with ultrasonic tips ET25 (Satelec Acteon, France) was used to trephine around the fragment. The procedure was carried out under magnifying loupes (×2.5 magnification) (Heine, Germany). The ultrasonic tip ET25 was activated at a power setting 6 to trephine dentin around the broken fragment [Figure 1]b. Canal was irrigated with normal saline intermittently to flush out the debris from the canal and act as a coolant. After about 30 min, the fragment loosened and popped out of the canal [Figure 1]c. IOPA was taken to confirm the removal of the separated instrument [Figure 1]d. Working length was then determined, and cleaning and shaping of the root canal system were performed using Hero Shaper rotary file system (Micro-Mega, Besancon, France). Obturation of the pulp space was done with thermoplastic gutta-percha using Calamus unit (Dentsply Maillefer, Ballaigues, Switzerland) [Figure 1]e and [Figure 1]f. After obturation, the tooth was restored with composite restoration (Filtek Z350 XT Universal Restorative, 3M India) followed by porcelain fused to metal crown.

Case Report 2

A 30-year-old male patient was referred for root canal treatment with the complaint of episodic pain in the left mandibular first molar. Randomized controlled trial was initiated and while cleaning and shaping the canals with ProTaper Universal rotary file system (Dentsply Malliefer, Ballaigues, Switzerland) unfortunately ProTaper F2 file got separated in the mesiolingual canal at the coronal level [Figure 2]a. Remaining three canals were obturated in the same sitting and orifices sealed with glass ionomer cement. The patient was informed of this accidental event, and further procedure was rescheduled. Next day, the tooth was reopened, and modified GG drills no.3 (Dentsply Maillefer, Ballaigues, Switzerland) was used to prepare a staging platform. Acteon Satelec P5 newtron ultrasonic generator with ultrasonic tips ET20 (Satelec Acteon, France) at power setting 6 was used to trephine around the fragment using magnifying loupes (×2.5 magnification) (Heine, Germany). The fragment was removed, and a radiograph was taken to confirm separated file removal [Figure 2]b. Cleaning and shaping of the mesiolingual canal was performed using ProTaper Universal rotary file system and then obturated [Figure 2]c and restored with composite restoration.
Figure 2: Sequence of fragment removal in case 2. (a) Intraoral periapical showing separated instrument in mesiolingual canal of mandibular first molar and master cones in mesiobuccal, distobuccal, and distolingual canals. (b) Intraoral periapical showing fractured instrument removed from the mesiolingual canal. (c) Intraoral periapical showing obturated mandibular molar

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Case Report 3

A 38-year-old male patient was referred to our department with the chief complaint of pain in upper right front tooth region for the past 1 month, and he gave a history of incomplete root canal treatment done of the same tooth. A diagnostic radiograph revealed the presence of separated instrument in the middle third of maxillary right canine [Figure 3]a. Retrieval of the instrument was planned, and radicular access to the coronal end of the separated instrument was straightened by sequential use of modified GG drills. Ultrasonic tip ET20 (Satelec Acteon, France) was used to retrieve the broken instrument as described in case 1. During this procedure, canal was irrigated intermittently with normal saline to decrease the heat generated within the root canal and hence preventing the adverse effects on periodontal tissues. The instrument was retrieved successfully from the canal in approximately 1 h and a radiograph was taken to confirm the same [Figure 3]b. Canal was then prepared till F3 using ProTaper Universal rotary file system (Dentsply Maillefer, Ballaigues, Switzerland) followed by obturation using AH plus sealer [Figure 3]c. In the subsequent appointment, the patient was asymptomatic, and postobturation restoration was done with composite (Filtek Z350 XT Universal Restorative, 3M India) followed by porcelain fused to metal crown.
Figure 3: Sequence of fragment removal in case 3. (a) Intraoral periapical showing separated instrument in maxillary canine. (b) Intraoral periapical showing fractured instrument removed from the canal. (c) Intraoral periapical showing obturated maxillary canine

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  Discussion Top


Forcing an instrument into the canal or along a sharp curve, improper use, or overuse of an endodontic instrument leads to fracture of an endodontic instrument. The prognosis of the root canal treatment after the instrument separation depends on the stage of biomechanical preparation and debridement achieved at the time of instrument fracture.[4]

Several methods have been described for removal of separated instruments from the root canal such as Masserann kit, Endo Extractor, wire loop technique, and ultrasonics. However, successful removal of fractured instrument relies on factors such as length, type, and position of instrument in relation to canal curvature.[4] The safe removal of a separated instrument is influenced by the anatomy, canal curvature and limited by the root morphology and depth of external concavities. An instrument can be easily retrieved if it lies in the straightaway portion of the canal and if one-third of its overall length is exposed.[5],[6] If the broken instrument lies apical to canal curvature, then it is usually not possible to retrieve it. Stainless steel files can be removed easily as compared to NiTi files as NiTi files have a tendency for further fracture during retrieval due to heat buildup. The success rate of removing stainless steel instruments is 55%–70%.[4]

Although different retrieval techniques have evolved sometimes because of limited visibility or restricted space, removal of the instrument becomes difficult. Moreover, excessive canal enlargement during instrument retrieval can also lead to weakening and consequent fracture of the tooth or formation of iatrogenic ledges and root perforations.[7] When separated instrument does not seem possible to be removed then the decision to bypass the instrument with smaller size file should be considered. However, care should be taken while bypassing a separated instrument to avoid chances of iatrogenic errors such as perforation of the root or separation of the bypassing file. When efforts to retrieve the instrument are not successful then the prognosis of the tooth after root canal treatment can be compromised. Prevention is better than cure so while doing the root canal treatment factors such as proper access cavity, straight-line access, and glide path preparation should be considered.

Advancement in technologies and magnification aids has made instrument retrieval possible in majority of cases. The use of microscope or magnifying loupes guides the instrument retrieval and minimizes the damage to the canal dentine. According to Nevares et al. when the separated fragment was visible with a dental microscope the success rate of retrieval was 85.5% in comparison to when the fragment was not visible wherein the success rate was 47.7%.[5],[8]

The use of ultrasonics in endodontics was first described by Richman in 1957. Initially, the frequencies employed in ultrasonic units were 25–40 kHz, but subsequently, ultrasonic handpieces operating at 1–8 kHz were developed which produce less shear stresses causing less alteration to the canal surface. In the present case, the separated instrument is removed with the Aceton Satelec P5 neutron which is piezoelectric ultrasonic generator. The tips of these units work in a linear, back and forth, “piston-like” motion, which is ideal for endodontics.[4],[9],[10],[11] Heat is generated due to the friction of ultrasonic tips against canal wall dentine or fractured instrument which may lead to faster instrument fatigue and secondary fracture, so ultrasonic tips are used at low power settings of the ultrasonic unit and shorter application times.[8]

When retrieval is not possible, then instrument can be bypassed and retained separated instrument can be incorporated into the obturation.[5] Separation of the file can be prevented by adhering to proven concepts of biomechanical preparation and discarding endodontic instruments after each case. Prevention is the best strategy for a fractured instrument in the root canal.

In the above case reports, the separated instruments have been retrieved successfully with ultrasonic technique which is a safe and conservative method. Use of magnification also contributed to the success of the procedure. The separated fragments were retrieved in short duration of time with minimal dentine removal. Ultrasonics offers a predictable method of retrieving separated instruments from the root canal.


  Conclusion Top


The development in technology, advanced armamentarium, and expertise enable successful management of fractured instrument. The ultrasonic technique renders a predictable method of retrieving separated instruments from root canal with minimal loss of dentine.

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.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Crump MC, Natkin E. Relationship of broken root canal instruments to endodontic case prognosis: A clinical investigation. J Am Dent Assoc 1970;80:1341-7.  Back to cited text no. 1
    
2.
Sattapan B, Nervo GJ, Palamara JE, Messer HH. Defects in rotary nickel-titanium files after clinical use. J Endod 2000;26:161-5.  Back to cited text no. 2
    
3.
Al-Zahrani MS, Al-Nazhan S. Retrieval of separated instruments using a combined method with a modified vista dental tip. Saudi Endod J 2012;2:41-5.  Back to cited text no. 3
  [Full text]  
4.
Chhina H, Hans MK, Chander S. Ultrasonics: A novel approach for retrieval of separated instruments. J Clin Diagn Res 2015;9:ZD18-20.  Back to cited text no. 4
    
5.
Nevares G, Cunha RS, Zuolo ML, Bueno CE. Success rates for removing or bypassing fractured instruments: A prospective clinical study. J Endod 2012;38:442-4.  Back to cited text no. 5
    
6.
Ruddle CJ. Broken instrument removal. The endodontic challenge. Dent Today 2002;21:70-2, 74, 76.  Back to cited text no. 6
    
7.
Shenoy A, Mandava P, Bolla N, Vemuri S. A novel technique for removal of broken instrument from root canal in mandibular second molar. Indian J Dent Res 2014;25:107-10.  Back to cited text no. 7
[PUBMED]  [Full text]  
8.
Madarati AA. Retrieval of multiple separated endodontic instruments using ultrasonic vibration. J Taibah Univ Med Sci 2016;11:268-73.  Back to cited text no. 8
    
9.
Lea SC, Walmsley AD, Lumley PJ, Landini G. A new insight into the oscillation characteristics of endosonic files used in dentistry. Phys Med Biol 2004;49:2095-102.  Back to cited text no. 9
    
10.
Plotino G, Pameijer CH, Grande NM, Somma F. Ultrasonics in endodontics: A review of the literature. J Endod 2007;33:81-95.  Back to cited text no. 10
    
11.
Ward JR, Parashos P, Messer HH. Evaluation of an ultrasonic technique to remove fractured rotary nickel-titanium endodontic instruments from root canals: An experimental study. J Endod 2003;29:756-63.  Back to cited text no. 11
    


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