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CASE REPORT
Year : 2018  |  Volume : 8  |  Issue : 3  |  Page : 217-221

The use of cone-beam computed tomography in localizing calcified canals during endodontic treatment


Department of Restorative Dental Science, College of Dentistry, King Saud University, Riyadh 11432, Kingdom of Saudi Arabia

Date of Web Publication25-Jul-2018

Correspondence Address:
Dr. Amal Abdullah Almohaimede
Dental College, P.O.Box 5967, Riyadh 11432
Kingdom of Saudi Arabia
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/sej.sej_2_18

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  Abstract 

Canal calcification and obliteration is considered a challenge during root canal treatment. The present case report demonstrates a successful management of calcified pulp chamber and coronal third of the root canals of lower right first molar tooth of a 17-year-old patient that was diagnosed as previously initiated with symptomatic apical periodontitis treated by pulpotomy for a long period. It also emphasizes the use of the aiding tools to negotiate such calcification including intraoperative cone-beam computed tomography. This technology, along with chelating agents, magnification, illumination, and ultrasonic instruments helped in assessing the extent and the depth of the calcification and guided the clinician to the correct location, angle, and depth to negotiate the patent part of the canals, and therefore adequately treated.

Keywords: Calcific metamorphosis, cone-beam computed tomography, dystrophic calcification, pulp canal obliteration, root canal treatment


How to cite this article:
Almohaimede AA. The use of cone-beam computed tomography in localizing calcified canals during endodontic treatment. Saudi Endod J 2018;8:217-21

How to cite this URL:
Almohaimede AA. The use of cone-beam computed tomography in localizing calcified canals during endodontic treatment. Saudi Endod J [serial online] 2018 [cited 2018 Dec 14];8:217-21. Available from: http://www.saudiendodj.com/text.asp?2018/8/3/217/237556


  Introduction Top


Calcific metamorphosis is a common phenomenon that occurs in young patients' teeth following calcium hydroxide (Ca(OH)2) pulpotomy therapy.[1],[2] The increased number of calcium ions leads to the reduction in capillary permeability, which will fail to operate the pyrophosphatase enzyme leading to uncontrolled mineralization.[3],[4] Therefore, the management of teeth with obliterated pulp chamber and calcified canals, which require root canal treatment, is a challenging therapy.[5]

The most commonly used technique to access a calcified canal is to carefully drill through the calcification following the long access of the tooth. Periapical radiograph at multiple angles should be taken to check the direction of the bur to avoid perforation.[6] Ultrasonic and dental operating microscope (DOM) are good tools that help in treating calcified canals.[7],[8] The American Association of Endodontics and the American Academy of Oral and Maxillofacial Radiology were recently updated the joint position statement regarding the use of cone-beam computed tomography (CBCT) in endodontic treatment. They recommended the use of limited field of view (FOV) CBCT in identification and localization of calcified canals.[9]

The purpose of this article was to report a successful management of calcified pulp chamber and coronal third of root canals of a molar tooth by nonsurgical root canal treatment and supported by CBCT scanning as a diagnostic imaging technique.


  Case Report Top


A 17-year-old Saudi female that was referred to the endodontic clinic complaining of mild-to-moderate pain related to lower right posterior teeth during biting. The patient reported that she started pulpal therapy (pulpotomy) in her lower first right molar (#46) when she was 8 years old. She is medically fit, and according to the American Society of Anesthesiologists (ASA) classification, she is class ASA I.[10]

Clinical examination of tooth #46 showed a glass ionomer restoration. Percussion test revealed mild-to-moderate tenderness and no pain with palpation test. Sensibility test indicated no response, with no signs of swelling, sinus tract, mobility, or deep pockets.

Preoperative periapical radiographic examination revealed periapical radiolucency, narrow mesial canals, and a restorative material encroaching the pulp chamber that was partially calcified [Figure 1]. The tooth was diagnosed as previously initiated with symptomatic apical periodontitis, and the recommended endodontic treatment was nonsurgical.
Figure 1: Preoperative periapical radiograph of tooth #46 showing periapical radiolucency related to the mesial root

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The tooth was isolated with a rubber dam, and after proper deroofing of the pulp chamber, the distal canal was accessed; however, both mesial canals were not accessed due to complete orifice calcification. The floor of the pulp chamber was shiny and hard to drill through. Under the microscope (ZEISS microscopy, Jena, Germany), two distal canals, distobuccal (DB) and distolingual (DL), were negotiated. However, the mesial canals could not be negotiated. In the second visit, a decision was taken to view the area with CBCT to locate the mesial canals [Figure 2]a. The mesiolingual (ML) canal was completely calcified compared to the mesiobuccal (MB) [Figure 2]b,[Figure 2]c,[Figure 2]d,[Figure 2]e. Measurements were taken from the floor of the pulp chamber to the first point where the ML and MB canals start to appear in the sagittal view [Figure 2]f,[Figure 2]g,[Figure 2]h. Then, the canals were checked in the axial view [Figure 2]g and [Figure 2]i for areas of calcification and their locations within the canals. Depending on the measured areas along the canal for areas of patency and areas of calcification, drilling within the canals was started using ultrasonic tips (P5 Newtron XS, SATELEC, ACTEON, US) where the MB canal was negotiated [Figure 3]a, then finally, the ML canal was accessed [Figure 3]b. Ethylenediaminetetraacetic acid solution (17% EDTA) (SmearClear , Kerr Dental, Orange, California, USA) was used to remove the inorganic debris. Working length was determined using apex locator (Root ZX II J. Morita, Tokoyo, Japan), and confirmed with periapical radiograph. It showed that the two distal canals (DB and DL) were joined at the apical third, and the mesial canals, ML and MB, were separated [Figure 4]a.
Figure 2: (a) Cone-beam computed tomography sagittal view for tooth #46 showing the large periapical lesion. (b) Coronal view showing complete calcification of mesiolingual canal. (c) Sagittal view. (d) Coronal view showing coronal calcification of mesiobuccal canal. (e) Sagittal view. (f) Sagittal view showing measurements taken from the floor of the pulp chamber to the first point where the mesiolingual canal was patent. (g) Axial view to follow the patency of the mesiolingual canal. (h) Sagittal view showing measurements taken from the floor of the pulp chamber to the first point where the mesiobuccal canal was patent. (i) Axial view to follow the patency of the mesiobuccal canal

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Figure 3: Access cavity after negotiating the mesiobuccal canal (a) and the mesiolingual canal (b)

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Figure 4: (a) Initial WL radiograph after negotiating the 4 canals (a). Final radiograph after obturation (b)

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All canals were cleaned and shaped using K3 Rotary files (SybronEndo, Orange, California, USA). The DB canal was shaped with K3 0.06 up to size 40, the DL, MB, and ML canals with K3 0.04 up to size 40. Sodium hypochlorite (5.25%) (20 mL) was used as an irrigant. The master gutta-percha cones were checked, and obturation was completed with continuous wave condensation technique and AH-Plus sealer (Dentsply Maillefer, Ballaigues, Switzerland) [Figure 4]b. The access cavity was sealed with a temporary filling material (GC Fuji II LC, Vivadent-Ivoclar) and the patient was referred for the final restoration.


  Discussion Top


The current case had a pulpotomy treatment with Ca(OH)2 that was left in the pulp chamber for a long period. It is characterized by its ability to induce reparative bridge formation when applied to vital pulpal tissues.[11] However, the pulp chamber and the pulp canal entrances can be subjected to dystrophic calcification after being exposed to Ca(OH)2 for a long period.[1] It was suggested that the high alkaline pH level of Ca(OH)2 irritates the pulp cells and activates the release of bioactive molecules, which stimulate pulpal repair and therefore induce mineralization.[12] Moreover, pulp necrosis may occur due to the reduction of blood supply by this calcification.[13]

The presence of such calcifications is considered a challenge during root canal treatment. Several materials and instruments were used to facilitate overcoming such challenge. Chelating agents in the form of liquid or paste were reported to provide a good help in preparing calcified and narrow root canals.[14],[15],[16],[17] In this case report, a liquid EDTA (17%) solution was used. It has the ability to demineralize and decalcify dental hard tissues.[18],[19],[20] It was recommended to apply the EDTA solution into the pulp chamber to identify the entrance to calcified canals.[15] Goldberg and Spielberg mentioned that the optimal cleaning effect for a chelator is only achieved after 15 min.[21] In contrast, McComb and Smith showed that a chelator had a better effect when it was left for 14 h in the root canal.[22] Furthermore, Weine mentioned in his study that chelating agents may remain active within the canal for 5 days if not inactivated.[23] In this case, EDTA solution was placed in the calcified pulp chamber in between appointments.

Moreover, the use of sodium hypochlorite (NaOCl) may help in identification a calcified canal through the “bubble test” by placing full concentration of NaOCl into the pulp chamber over a calcified canal that contains remnants of pulp tissue, which will result in bubbles formation from the oxygenated tissue.[24] This technique did not help in the current case. The use of the DOM in treating obliterated canals was reported to improve the treatment outcome. This was shown in several studies.[7],[8],[24],[25],[26] Furthermore, variously designed burs and ultrasonic tips have been used to facilitate entering the calcified pulp chambers and canals by performing a deep troughing.[5] In the present case, the DOM and ultrasonic were effective in negotiating the calcification.

Conventional radiography is usually used as the primary imaging modality for assessment of the teeth. However, they represent only a two-dimensional (2D) image of a three-dimensional (3D) object.[27] In addition, the absence of cross-sectional information in the 2D images prevents accurate interpretation of such images.[28]

CBCT was used in the present case. It provides thinly sliced sections in axial, sagittal, and coronal planes of the examined subject.[29] This advantage reduces the anatomic superimposition produced by conventional radiography,[29],[30],[31] and provides the clinicians with an undistorted 3D representation of the anatomic structures.[27],[28],[32]

In this study, the advantage of CBCT in demonstrating anatomic images helped in successful negotiating of the calcified canals without adverse mishaps such as perforations. The preoperative periapical radiograph showed narrow mesial canals; however, the CBCT showed calcified ML canal (at coronal and middle third) and partial calcification in the MB canal. A study was conducted to detect the correspondence of the radiographic diameter size of a canal with its true diameter, by comparing the canal size on the periapical radiographs with the actual canal diameter histologically. It was concluded that there was a correlation between the radiographic and the histological canal size.[33] However, it was mentioned that the two measurements varied clinically, where the canals could be clear radiographically, but difficult to be located clinically due to the smaller actual size. Contrarily, canals that appear completely calcified radiographically could be easily negotiated clinically. This was explained by the difference in the degree of mineralization between the primary and the secondary dentin, where the secondary dentin is considered less radiodense, which will give the radiographic appearance of a canal with a smaller diameter.[34],[35] In this case, CBCT helped in assessing the extent and the depth of the calcification and provided a guide to the corrected location, angle, and depth to negotiate the patent part of the canals, and therefore properly treated.

The use of CBCT should follow the as low as reasonably achievable (ALARA) principles, in which patients should be exposed to radiation as low as reasonable achievable.[36] However, a modification of the ALARA principle was introduced as ALADA, which stands for “As Low As Diagnostically Acceptable.” That means to have an image that is diagnostically acceptable and interpretable by emphasizing on the real indications and referrals of CBCT, also by choosing the appropriate settings of FOV, milliamperage-seconds, and kilovoltage peak, and by applying high-resolution parameters.[37]


  Conclusion Top


Several aiding tools should be used to negotiate calcified pulp chambers and canals to improve the treatment outcome. The use of CBCT cannot substitute the use of the conventional radiography. However, the advantages and the indications to use this technology should be considered.

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

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  [Figure 1], [Figure 2], [Figure 3], [Figure 4]



 

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