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Year : 2021  |  Volume : 11  |  Issue : 2  |  Page : 271-276

Surgical management of a persistent periapical lesion using cone-beam computed tomography

Department of Restorative Dental Sciences, Division of Endodontics, College of Dentistry, King Saud University, Riyadh, Saudi Arabia

Date of Submission01-Oct-2020
Date of Decision20-Nov-2020
Date of Acceptance05-Dec-2020
Date of Web Publication8-May-2021

Correspondence Address:
Dr. Ziyad Allahem
Department of Restorative Dental Sciences, Division of Endodontics, College of Dentistry, King Saud University, Riyadh 11545
Saudi Arabia
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/sej.sej_260_20

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Endodontic therapy has a high success rate. However, failed endodontic therapy with persistent periapical lesions may indicate the presence of an apical cyst that requires surgical apical intervention. The present case involved a 70-year-old woman who was referred after initiation of nonsurgical root canal treatment (NSRCT) in the upper left lateral incisor (tooth #22); due to recurrent swelling and sinus tract. Periapical radiographs showed an apical radiolucency on tooth #22. In a clinical examination, tooth #22 showed a normal response to cold and the electric pulp tester (EPT), while the upper left canine (tooth #23) showed a negative response to cold and the EPT. NSRCT was performed for tooth #23. Eighteen months later, the patient presented with the same chief complaint of recurrent swelling, and cone-beam computed tomography was performed to examine the extent of the apical lesion and plan for surgical intervention. Apical surgery was performed using a dental operating microscope. At the 18-month follow-up assessment, the patient's radiographs showed good bone healing and symptom resolution. This case report indicates that some cases with large persistent periapical lesions may require surgical intervention.

Keywords: Apical cyst, case report, cone-beam computed tomography, endodontic diagnosis, root canal treatment

How to cite this article:
Allahem Z. Surgical management of a persistent periapical lesion using cone-beam computed tomography. Saudi Endod J 2021;11:271-6

How to cite this URL:
Allahem Z. Surgical management of a persistent periapical lesion using cone-beam computed tomography. Saudi Endod J [serial online] 2021 [cited 2023 Mar 28];11:271-6. Available from: https://www.saudiendodj.com/text.asp?2021/11/2/271/315647

  Introduction Top

Endodontic therapy, including nonsurgical root canal treatment (NSRCT), has a high success rate.[1] However, inaccurate diagnosis and poor treatment planning may lead to unnecessary/incorrect treatment. In comparison with clinical examination findings, which represent the gold standard, assessments based exclusively on radiographs show an accuracy rate of 36%–40%, while those using cone-beam computed tomography (CBCT) show an accuracy rate of 77%–83%.[2] In one study, treatment plans based on periapical (PA) radiographs required changes in 62% of the cases after endodontists were shown the CBCT scans.[2]

The American Academy of Oral and Maxillofacial Radiology and American Association of Endodontists position statement in 2015 did not recommend CBCT for routine examination and categorized a list of indicated uses based on evidence. One of the recommendations was to use CBCT in cases of persistent lesions to facilitate the choice between non-surgical retreatment, surgical treatment, or extraction.[3] CBCT has also been recommended for treatment planning of endodontic surgeries,[4],[5] since it can detect up to 48% of primary endodontic lesions while intraoral radiographs have a detection rate of only 20%.[6] Tsai et al. simulated PA lesions in cadaver jaws to compare the accuracy of PA radiographs and CBCT and reported that the accuracy of CBCT was excellent for lesions larger than 1.4 mm, fair to good for lesions between 0.8 and 1.4 mm in size, and poor for lesions smaller than 0.8 mm while PA radiographs showed poor accuracy for all lesion sizes.[7] CBCT reviews can thus facilitate better pulpal and apical diagnoses, determination of etiological factors, and planning of appropriate treatments.[2],[8],[9]

Several histopathological studies have evaluated apical lesions. Apical granulomas constitute the majority of periapical lesions, while the prevalence of apical cysts ranges from 6% to 55%.[10] Ramachandran Nair et al. reported that serial sectioning or step sectioning is necessary to accurately diagnose apical lesions as cysts.[10] Histopathological studies using serial sectioning showed that the prevalence of apical cysts was between 6%–32%, and that true apical cysts constituted 48%–62% of the total cyst cases.[10],[11],[12],[13] Four different theories have been introduced to explain epithelial rest of Malassez proliferation and cyst formation, namely, immunological theory, breakdown theory, abscess theory, and trapped connective tissue theory.[13]

For the diagnosis of apical cysts, histopathological examination of biopsy specimens obtained in surgery is considered the gold standard.[12],[14] However, other methods that do not involve surgery have also been suggested to differentiate cysts from granulomas. Simon et al. proposed using CBCT grey values to differentiate cysts from granulomas, and their CBCT assessments matched the surgical pathology reports in 13 of 17 cases involving periapical lesions.[15] CBCT allows moderately accurate distinction between cysts and granulomas for cysts larger than 5 mm.[16] Lin et al. indicated that most reactive lesions, either cysts or granulomas, might heal with root canal treatment alone, unlike true apical cysts, which require surgical intervention.[17],[18]

The present case report describes the findings for a patient complaining of persistent sinus tract who underwent surgical management based on CBCT assessments.

  Case Report Top

A 70-year-old woman was referred from her general dentist after initiation of root canal treatment. She had a medical history of hypertension (50 mg atenolol and 100 mg of losartan, both taken once daily) and hyperlipidemia (simvastatin 20 mg once daily). Her chief complaint was recurrent swelling on the left upper anterior side over the past few months. Her general dentist had planned to do root canal treatment for the upper left lateral incisor, but during the access cavity preparation, the patient experienced pain. Therefore, the dentist paused the treatment and referred the patient for further diagnosis and treatment.

The patient's old preoperative radiographs [Figure 1]a and [Figure 1]b revealed an apical radiolucency on the upper left lateral incisor (tooth #22) extending mesial to the upper left central incisor (tooth #21) and distal to the upper left canine (tooth #23). Tooth #22 had a class III and V glass ionomer cement (GIC) filling and access cavity sealed with Cavit filling [Figure 2]. Her initial examination was conducted under weak anesthesia and showed the following responses to cold and the electric pulp tester (EPT), cold (#22, 23: no response), (#21: normal) and EPT: (#21, 22: response), (23: no response). The pulp in tooth #22 was considered to be vital since this tooth showed a response to the EPT, and vital pulp tissue was present in the access cavity. Treatment options for tooth #22 were discussed with the patient, and she chose to undergo direct pulp capping and informed consent was obtained. A rubber dam was placed, and Cavit was removed; subsequently, the tooth was irrigated with 5.25% NaOCl, direct pulp capping was performed with white mineral trioxide aggregate (Dentsply Tulsa Dental, Tulsa, OK, USA), wet cotton was placed, and intermediate restorative material IRM (Dentsply, Konstanz, Germany) was used to seal the access. One week later, the patient underwent examinations without anesthesia to confirm the diagnosis. She was asymptomatic. Diagnostic testing [Table 1] concluded that tooth #22 was vital and diagnosed as normal with normal apical tissue, while tooth #23 was necrotic with asymptomatic apical periodontitis and required NSRCT. A cavity test was planned to confirm the diagnosis in tooth #23, and informed consent was obtained. Rubber Dam was placed on tooth #23. The access cavity was prepared without local anesthesia, and the canal was located. There was no evidence of bleeding or vital tissue, and the pulp was confirmed as necrotic. The canal length was measured using an electronic apex locator (Root ZX II; J. Morita Corp., Kyoto, Japan). Root end patency was achieved with a #10 K-file. The canal was instrumented using Protaper F2 and then finished with Vortex 40/04 (Dentsply/Tulsa Dental Co, Tulsa, Oklahoma) with 5.25% NaOCl irrigation and 17% EDTA. The canal was dried with paper points, and calcium hydroxide (UltraCal XS, Ultradent, South Jordan, UT, USA) was placed. The access cavity was sealed with cotton pellets and Cavit (3M, ESPE, St. Paul, MN, USA). Occlusion was checked, and postoperative instructions (POI) were provided. The NSRCT was continued two weeks later: The patient was asymptomatic and received 1.7 mL of 2% lidocaine (34 mg) with 1:100,000 epinephrine (0.017 mg) via local buccal infiltration. Rubber Dam was placed, and Cavit and cotton pellets were removed. Calcium hydroxide was removed using 5.25% NaOCl and 17% EDTA. The master gutta-percha cone was fit to working length, and its length was verified radiographically. The canal was obturated with gutta-percha and Kerr PC sealer (Kerr, Romulus, MI, USA) using the warm vertical condensation technique. Tooth was temporized with cotton and Glass Ionomer Cement restoration (3M, ESPE, St. Paul, MN, USA). Occlusion was checked, and postoperative radiographs were obtained and reviewed [Figure 3]a and [Figure 3]b. The patient and general dentist were advised to have the access cavity restored on tooth #23. A one-year follow-up assessment was scheduled.
Figure 1: Pre-operative radiographs of different angles obtained by patientfs general dentist. It shows large periapical radiolucency at the root apex of tooth #22 (a and b)

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Figure 2: The access cavity of tooth #22 sealed with Cavit filling

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Figure 3: Periapical radiographs showing endodontic treatment of tooth#23, and mineral trioxide aggregate capping for exposed vital pulp of tooth #22 (a and b)

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Table 1: Results of diagnostic testing

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The patient presented 1.5 years later with recurrent swelling. Intraoral examination revealed swelling buccal to tooth #22 with a sinus tract. The sinus tract was traced and it was pointing to mid-root of tooth #22 in the radiograph [Figure 4]a and [Figure 4]b. Periapical radiographs showed no apparent healing. Percussion on teeth #22, 23 was normal, cold test for #22 showed no response, while EPT elicited a response for #22. CBCT was requested, which showed a large low radiodensity lesion around teeth 21-23 that was more associated with tooth #23 [Figure 5].
Figure 4: Two different angles periapical radiographs with sinus tract tracing, at 18 months recall of root canal treatment of tooth #23 (a and b)

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Figure 5: Cone-beam computed tomography scans showing a large periapical low radiodensity area involving the apical area of teeth #22 and #23

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Treatment options were discussed with the patient and another endodontist was consulted. The patient agreed to undergo NSRCT for #22 followed by an apical surgery. Informed consent was obtained for this procedure. NSRCT was initiated and the tooth was deemed vital, but we chose to continue with the procedure, medicated the canal with calcium hydroxide, and then followed up (the NSRCT for tooth #22 was similar to that for tooth #23). The NSRCT was continued two weeks later. The patient was asymptomatic, but the sinus tract was still present. The obturation was performed, and surgery was scheduled.

One week later, the patient presented for endodontic surgery on tooth #23 and affirmed her informed consent for the procedure. She received 1.7 mL of 2% lidocaine (34 mg) with 1:100,000 epinephrine (0.017 mg) via buccal and palatal infiltration, and 1.7 mL of 2% lidocaine (34 mg) with 1:50,000 epinephrine (0.034 mg) via buccal local infiltration. A full-thickness flap was raised from the distal portion of the upper left second premolar (tooth #25) to the mesial portion of the upper right central incisor (tooth #11) with a vertical releasing incision at tooth #25. Two bony fenestrations were identified, one between the mid-roots of #22 and 23 and one apical to #23. Osteotomy was performed with a surgical round bur and 0.9% sterile saline solution apical to #23. A very large capsulated lesion was identified [Figure 6]a. The lesion tissue was curetted and collected for biopsy. Hemostasis was achieved using epinephrine hemostatic pellets (Racellet #2; Pascal International, Bellevue, WA, USA). The surgical site was rinsed with 0.9% sterile saline solution. The flap was re-approximated and sutured with seven 5.0 Vicryl sutures. Hemostasis was achieved with pressure. Endodontic surgery was performed under a dental operating microscope. A postoperative radiograph was taken [Figure 6]b. Written and verbal postoperative instructions were provided. The patient was given ice packs to place on the area along with extra gauze. She was advised to take 600 mg ibuprofen every 6 hours for the first 24 hours and subsequently rinse the mouth with warm water and salt for 30 seconds a few times a day for 3–4 days. The biopsy report obtained three days after the procedure revealed a periapical cyst. Five days later, the patient presented for suture removal. The surgical site was healing well by primary intention with mild discomfort. The patient was advised to return for a follow-up assessment after a year or earlier if she developed any symptoms.
Figure 6: Clinical photograph after flap reflection showing bony defect window (a). Post-surgical periapical radiograph (b)

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The patient presented for a follow-up examination after 1.5 years and reported that no swelling had occurred since the surgery. Percussion and palpation were within normal limits. Radiographs of tooth #23 showed healing and resolution of the radiolucency [Figure 7]a and [Figure 7]b.
Figure 7: Two different angle periapical radiographs 18 months after apical surgery, showing good healing (a and b)

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  Discussion Top

Periapical radiograph is frequently used for endodontic diagnosis because of its availability, ease of use, and low radiation exposure, but the absence of three-dimensional data may lead to inaccurate diagnosis.[19],[20] In the present case, the initial diagnosis based on PA radiographs was inaccurate and exposed the patient to unnecessary treatment. These findings indicate the utility of CBCT since it increases the confidence of endodontists to diagnose and plan treatment in complex cases.[21] In the present case, the patient's general dentist initially attributed the recurrent swelling to tooth #22 on the basis of PA radiographs. However, the patient experienced some discomfort during preparation of the access cavity. In my initial examination under weak anesthesia, vital pulp tissue in the access cavity was visible under a dental operating microscope, and the patient showed a response to EPT in tooth #22, but not #23, with no response to cold for both teeth, which could be attributed to the residual effects of anesthesia. Direct pulp capping was selected for the tooth #22. It was chosen due to fake results of pulp test because of anesthesia. Direct pulp capping has a high reported success rate that is not influenced by age (96% in mature teeth over three years),[22] and a survival rate of 90% over a follow-up period of 5 years.[23] However, in the following visit, tooth #23 was diagnosed as necrotic with asymptomatic apical periodontitis, since it showed no response to cold or EPT, while tooth #22 showed a normal response to both. Thus, tooth #23 was the source of the lesion despite its misleading radiographic presentation. The tooth underwent root canal treatment without anesthesia to confirm pulp necrosis; the pulp could be accessed without pain, and no vital tissue was discovered. Subsequently, calcium hydroxide was used as an intracanal medicament for 2 weeks to help prevent the growth of bacteria due to its high pH,[24] after which obturation was performed and the final restoration was placed. However, the patient presented 1.5 years later with recurrent swelling and sinus tract. The periapical radiograph obtained at this follow-up evaluation showed persistent apical lesion and no bone healing. CBCT confirmed the presence of a large apical radiolucency involving multiple teeth. The diameter of the PA radiolucency was more than 10 mm × 10 mm, and it extended toward the nasal floor, indicating its cystic behavior.[16] Lin et al. concluded that while most apical lesions heal after proper root canal treatment, true apical cysts, which show no communication between the cyst and root canal, do not.[17],[18] The endodontic surgery and the histopathology report confirmed the presence of a cyst. Ricucci et al. challenged the concept of bay (pocket) and true apical cysts by showing the absence of histopathological or histobacterial differences between them.[13] They also reported that a true apical cyst could contain bacteria inside the lumen. In the present case, no apical resection or retrofill was performed, since the lesion appeared like a cyst with a large lumen and no granulation tissue during the surgery, in addition; the canal was well-sealed, and the root apex was deeply curetted and cleaned. Similar case reports presented similar results, wherein no apical resection and retrofill were performed and a good healing outcome was obtained in the follow-up assessment.[25],[26] At a follow-up assessment 1.5 years later, the patient reported no pain or symptoms, and radiographic examinations showed good bone healing.

A CBCT examination should be routinely performed in endodontic practice to facilitate diagnosis and treatment planning when indicated. However, the use of CBCT may be limited by cost and time considerations.[27]

  Conclusion Top

Careful examination and correlation of radiographic and clinical findings are crucial for appropriate diagnosis and treatment. CBCT can be helpful in cases involving complex diagnoses and surgical procedures. Patients with large apical lesions may require additional surgical intervention to promote lesion healing.

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


Conflicts of interest

There are no conflicts of interest.

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  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]

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