Journal of Conservative Dentistry
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Year : 2023  |  Volume : 26  |  Issue : 2  |  Page : 241-245
Guidodontics: A global positioning system (GPS) to surgical Endodontics – A case series

Department of Conservative Dentistry and Endodontics, Babu Banarasi Das College of Dental Sciences, Lucknow, Uttar Pradesh, India

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Date of Submission27-Nov-2022
Date of Decision14-Dec-2022
Date of Acceptance07-Jan-2023
Date of Web Publication16-Mar-2023


Endodontic treatment is associated with the risk of instrument separation due to multiple factors that create complications not only in further completion of the procedure but also on the final outcome and long-term prognosis of the treatment at times. Separated instrument retrieval is definitely challenging and technique sensitive, requiring a lot of clinical expertise for a successful therapy. All these hurdles make such cases a nightmare to the clinician. This case report presents two clinical cases in which cone-beam computed tomography (CBCT)-guided surgery was used for retrieval of separated instruments extending beyond the confines of root canals in a mandibular molar and maxillary premolar. This novel approach utilizes a customized 3D printed surgical guide fabricated with the help of CBCT, which is stabilized intraorally, helping in predefining the osteotomy site, angulation and depth required for retrieval of separated instruments without performing apicoectomy or root end filling. CBCT also plays an important role in these cases as the actual size, location, and depth of the separated instrument can be appreciated preoperatively. In the present cases, 3D surgical guides helped clinicians to selectively retrieve the separated instruments more conservatively and predictably. Furthermore, complete healing was seen within 3 months in both cases.

Keywords: Cone-beam computed tomography; guided endodontics; guidodontics; instrument retrieval; surgical guides; three-dimensional printing

How to cite this article:
Sudha A, Krishnan A, Samant PS, Dubey S. Guidodontics: A global positioning system (GPS) to surgical Endodontics – A case series. J Conserv Dent 2023;26:241-5

How to cite this URL:
Sudha A, Krishnan A, Samant PS, Dubey S. Guidodontics: A global positioning system (GPS) to surgical Endodontics – A case series. J Conserv Dent [serial online] 2023 [cited 2023 Jun 7];26:241-5. Available from:

   Introduction Top

Instrument separation within the root canal is a very unfortunate occurrence that creates a problem with the further procedures and has the potential to impede the outcome too. These hindrances make separated instrument cases like nightmare, which are difficult to manage.[1],[2],[3]

Retrieval of separated instruments is of utmost importance because of two chief concerns. Primarily, there is the possibility of the metal fragment getting corroded over a period of time.However, the only case report available concluded that the inert nature of stainless steel fragment prevented it from undergoing corrosion in a time duration of 2 years.[3],[4] Second, the presence of separated instruments within the lumen of the canal creates hindrance in reaching the canal's apical terminus, compromising the effectiveness of cleaning and shaping, thus affecting the long-term prognosis of the tooth.[3]

There are various approaches that have been opted for the management of separated instruments at different levels, for example, using chemical solvents, chiefly by the use of ethylenediaminetetraacetic acid for softening of the root canal wall dentin surrounding the separated instrument, aiding in the placement of another file to engage the separated instrument in a braiding fashion and pull it back.[5] Another conventional way employs softened gutta-percha points for engaging the separated instruments.

The introduction of different mini-forceps for grasping and retrieval of obstructions within the root canals paved a newer way for the management of such cases. Some examples include Stieglitz forceps (Union Broach, York, PA); Peet silver point forceps (Hu-Friedy, Chicago, IL, USA); and Endo Forceps (Roydent, Johnson City, TN, USA).[5]

Furthermore, the emergence of newer techniques for separated instrument retrieval like the wire-loop technique, the use of hypodermic surgical needles; and different instrument retrieval kits, including Masserann kit (Micro-Mega, Besancon, France), Canal finder system (Societe Endo Technique, Marseille, France), Instrument removal system (DENTSPLY Tulsa Dental, Tulsa, OK), Terauchi file retrieval kit (TFRK, Dental care, Santa Barbara, California, USA), etc., aids in the successful removal of separated instrument fragments.[5]

The application of ultrasonic tips for instrument retrieval is another conservative way of managing separated instruments.

In situations where separated instrument is extending beyond the confines of root canal space and anatomical hindrances complicates the retrieval of the same by the above mentioned methods, surgical management can be a conclusive treatment option. However, surgical management can result in the loss of excess of bone and risk the surrounding vital structure too. Therefore, in order to overcome such complications, guided endodontic surgery, the recently introduced approach, can be opted as a treatment of choice, especially for retrieval of instruments extending beyond the apex. The approach works on the concept of navigation, and makes use of guide, formed before the initiation of treatment, thus helping in conserving maximum tooth, with minimal chances of damage to the surrounding vital structure and with minimal chances of deviation from the area of interest.[6]

   Case Series Top

Case 1

A 35-year-old female patient reported to the Department of Conservative Dentistry and Endodontics, with the chief complaint of pain in the lower right back teeth region of the jaw for 2–3 weeks. The patient gave a history of attempted root canal treatment in the same tooth about a month ago. Clinical examination revealed tenderness on percussion in #47, without any sign of pus discharge or sinus tract. Radiographic examination revealed separated instrument extending 1–2 mm beyond the confines of the mesiobuccal canal of the tooth [Figure 1]a. Based on clinical and radiographic observations, the case was diagnosed as previously initiated treatment with symptomatic apical periodontitis with respect to 47.
Figure 1: (a) Preoperative radiograph (b) Reflection of full-thickness flap (c) Customized guide used in the surgery. (d) Osteotomy through the guide using bone trephine. (e) Bony window created by the bone trephine at the apex of #47. (f) Harvested cortical bone. (g) Radiographic verification of osteotomy site. (h) Clinical picture of separated instrument visible through the osteotomy site. (i) Radiographic verification after removal of separated instrument. (j) Placement of the harvested bone at the osteotomy site (autologous graft) (k) Immediate postoperative radiograph. (l) Radiograph at 6-month follow-up

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Attempts were made for the retrieval of separated instruments, failing in which a guided endodontic surgery was planned after the informed consent being signed by the patient.

Endodontic consideration and cone-beam computed tomography scanning

The working length determination of the remaining canals was made, and biomechanical preparation was completed, after which endodontic surgery with a conservative approach that is, guided surgery was planned.

After biomechanical preparation, a limited FOV cone-beam computed tomography (CBCT) scan (X-Mind TRIUM, Acteon, Italy) of the respective tooth was made. The DICOM file obtained was reconstructed further into standard tessellation language (STL) file format with the help of DDS Pro (Digital Dental services, Poland) software, which aided in designing and three-dimensional (3D) printing of the surgical guide.

Before surgery, hematological investigations were carried out, and a duly signed informed consent was obtained from the patient. Antibiotics and chlorhexidine mouthwash were prescribed, a day before the surgery.

Surgical Intervention

Local anesthesia was administered, and a full-thickness mucoperiosteal flap was elevated, including the papilla was reflected with a horizontal secular incision and two vertical releasing incisions [Figure 1]b. The fit of the surgical guide was then verified.

Hard tissue management and osteotomy

A surgical guide [Figure 1]c with a metal collar of diameter and depth of 5 mm was held firmly against the bone and occlusal surface of the teeth to guide osteotomy. The bone trephine of diameter 4.8 mm, with depth gauges, was then inserted through the surgical guide up to the length of 8 mm (predetermined depth using CBCT), under copious irrigation [Figure 1]d.

The harvested cortical bony window after osteotomy was then removed and then stored in normal saline till the completion of the procedure [Figure 1]e and [Figure 1]f. Radiographic evaluation of the osteotomy site was done [Figure 1]g.

The separated instrument was pushed through the root canals till it was visible through the osteotomy site [Figure 1]h and could be pulled out using artery forceps, which was then verified radiographically [Figure 1]i. Canals were irrigated with chlorhexidine and saline, followed by drying with paper points and obturation conventionally [Figure 1]k.

Closure of surgical site

The harvested cortical bone was used as an autologous bone graft [Figure 1]j, and the flap was repositioned with the help of simple interrupted sutures (3-0 silk suture). Suture removal was done after 1 week.

Postsurgical considerations

Postoperative application of cold compresses with an ice pack for the first 4–6 h after surgery followed by warm saline rinses after 24 h was advised. Antibiotics and analgesics were prescribed for 5 days.

The patient was informed to revisit the department after 3 days to access the surgical site for healing and the absence of signs and symptoms such as pain and sinus tract. The patient was kept on a follow-up for 6 months and is still under observation [Figure 1]l.

Case 2

A 45-year-old female patient reported to the Department of Conservative Dentistry and Endodontics with the chief complaint of pain in the upper right back teeth region of the jaw for a few weeks. The patient gave a history of attempted root canal treatment in the tooth about 2 months ago. Clinical examination revealed, tenderness on percussion in #14, without any sign of pus discharge or sinus tract. Radiographic examination revealed, separated instrument extending 1–2 mm beyond the confines of the buccal canal of the tooth. Based on clinical and radiographic observations, the case was diagnosed as previously initiated treatment with symptomatic apical periodontitis with respect to 14.

The working length of the palatal canal was determined, followed by biomechanical preparation. The same abovementioned conservative guided surgical procedure was carried out for the retrieval of the separated instrument from the buccal canal of the tooth [Figure 2].
Figure 2: (a) Preoperative radiograph (b) Reflection of full-thickness flap (c) Osteotomy through the guide using bone trephine. (d) Bony window created by the bone trephine at the apex of #14. (e) Punched out cancellous bone. (f) Separated instrument visible from the osteotomy site. (g) Immediate postoperative radiograph. (h) Radiograph at 6-month follow-up

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   Discussion Top

Irrespective of the approach opted for the management of separated instruments, there are various potential complications that can occur as a result of excessive loss of the tooth structure, such as ledge formation, perforation, and fracture of the root. Complications associated with surgery include chances of damage to the surrounding vital structures, improper osteotomy site, damage to adjacent roots, etc.

The guided endodontic surgical approach for instrument retrieval is a very conservative procedure with great accuracy. The guides used in the case series were customized according to the approximation of the root apex with the mandibular nerve and the maxillary sinus in the first and second cases, respectively. CBCT-obtained DICOM files were converted to an STL file using DDS pro software, which helped in designing of the custom surgical guide. These 3D surgical guides constituted of a metallic sleeve of 5 mm depth, which acted as an escort to direct the osteotomy drills in predesigned angulation and depth, thus minimizing the risk of damage to the root apex. Guides were made from a resin-based material and derived its support completely from hard tissues. An important factor that can affect the accuracy of any guided procedure is the stability of the guide. In this case series, the guides obtained its stability from the occlusal extension and bone, and needed two-point stabilization during the progress of the procedure.

All the possible treatment plans, such as retrieval of the separated instrument, hemisection, intentional reimplantation, conventional endodontic surgery, and guided endodontic surgery, were informed and discussed with the patient, along with the pros and cons of each treatment plan.

Attempts to retrieve the instrument resulted in even more extrusion of the separated fragment. Hemisection (in case 1) was not an ideal treatment plan as it did not fall under the selection criteria for hemisection by Weine.[7] Furthermore, it might have complicated the prosthetic rehabilitation and long term prognosis due to missing adjacent tooth.

Another viable treatment option was intentional replantation, which despite of being technique sensitive, had other associated risks such as ankylosis, external root resorption, and periodontal ligament damage.[8],[9] Hence, this treatment option was also not selected.

The novel approach of guided surgical endodontics was opted over the conventional surgical approach because of its predictability, conservative nature, and minimal risk of deviation from the target site.

In this case series, the harvested bone obtained during osteotomy was used as autologous graft, during the closure of the surgical site. The advantage offered by the use of autologous graft is better biological properties. The use of cortical bone as autologous bone graft in case 1, provides a better initial mechanical stability and strength to bony fixation constructs,[10] as these are four times as dense as cancellous bone.[9] Whereas the use of cancellous bone graft as use in the second case, comprises a large surface area, thus allowing the high number of cellular components to be incorporated for excellent osteogenic and osteoinductive capabilities.[11],[12],[13]

The patients were kept on a follow-up of 6 months for clinical and radiographical evaluation. A very good healing was evident by the end of 3 months and the patients showed a complete absence of any clinical signs and symptoms within 2–3 weeks of the procedure. The placement of autologous bone graft at the osteotomy site showed a better and faster healing. Also, radiographic evaluation at the end of 6 months showed no signs of periapical radiolucency or periodontal ligament widening, thus indicating success of the treatment in both the cases. However, the patients are still under observation.

   Conclusion Top

The guided approach has proved to be a boon in the conservative management of cases of calcified canals, surgical endodontics, retrieval of separated instruments, and autotransplantation of the tooth. Unlike the conventional approach, the guided approach is conservative, precise, and less time taking, with the minimal possible risk of damage to the surrounding tissues. In this case series, the guided endodontic surgery has been carried out without the requirement of apicectomy and this approach can be groundbreaking procedure in the field of surgical endodontics.

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Conflicts of interest

There are no conflicts of interest.

   References Top

Strindberg L. The dependence of the results of pulp therapy on certain factors: An analytic study based on radiographic and clinical follow-up examination. Acta Odontol Scand 1956;14 Suppl 21:1-175.  Back to cited text no. 1
Torabinejad M, McDonald NJ. Endodontic surgery. In: Torabinejad M, Walton RE, editors. Endodontics Principles and Practice. 4th ed. St Louis: Elsevier Health Sciences; 2009. p. 357-75.  Back to cited text no. 2
Madarati AA, Hunter MJ, Dummer PM. Management of intracanal separated instruments. J Endod 2013;39:569-81.  Back to cited text no. 3
Eleazer PD. Lack of corrosion of stainless steel instruments in vivo by scanning electron microscope and microprobe analysis. J Endod 1991;17:346-9.  Back to cited text no. 4
Cattoni M. Common failures in endodontics and their corrections. Dent Clin North Am 1963;7:383-99.  Back to cited text no. 5
Hegde SG, Tawani G, Warhadpande M, Raut A, Dakshindas D, Wankhade S. Guided endodontic therapy: Management of pulp canal obliteration in the maxillary central incisor. J Conserv Dent 2019;22:607-11.  Back to cited text no. 6
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Weine FS: Endodontic Therapy. 5th ed. St. Louis: Mosby Co.; 2006.  Back to cited text no. 7
Ong TK. Non-surgical retreatment after failed intentional replantation: A case report. Eur Endod J 2019;4:145-9.  Back to cited text no. 8
Deshpande NM, Shah D, Wadekar S. Maintenance of cell viability in extraoral conditions for a case of intentional replantation to retrieve a separated endodontic instrument. J Conserv Dent 2019;22:207-12.  Back to cited text no. 9
[PUBMED]  [Full text]  
Pape HC, Evans A, Kobbe P. Autologous bone graft: Properties and techniques. J Orthop Trauma 2010;24 Suppl 1:S36-40.  Back to cited text no. 10
Giannoudis PV, Dinopoulos H, Tsiridis E. Bone substitutes: An update. Injury 2005;36 Suppl 3:S20-7.  Back to cited text no. 11
Schmidmaier G, Herrmann S, Green J, Weber T, Scharfenberger A, Haas NP, et al. Quantitative assessment of growth factors in reaming aspirate, iliac crest, and platelet preparation. Bone 2006;39:1156-63.  Back to cited text no. 12
Khan SN, Cammisa FP Jr., Sandhu HS, Diwan AD, Girardi FP, Lane JM. The biology of bone grafting. J Am Acad Orthop Surg 2005;13:77-86.  Back to cited text no. 13

Correspondence Address:
Dr. Aishwarya Sudha
Opposite M.M.M Engg. College, Mahadevpuram Colony, Kunraghat, Gorakhpur - 273 008, Uttar Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jcd.jcd_614_22

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