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Table of Contents
CASE REPORT
Year : 2016  |  Volume : 6  |  Issue : 2  |  Page : 80-86

Endodontic applications of cone beam computed tomography: A series of case reports


1 Department of Conservative Dentistry and Endodontics, Meenakshi Ammal Dental College and Hospital, Chennai, Tamil Nadu, India
2 Department of Conservative Dentistry and Endodontics, VS Dental College and Hospital, Bengaluru, Karnataka, India

Date of Web Publication5-Jan-2017

Correspondence Address:
Dinesh Kowsky
Department of Conservative Dentistry and Endodontics, Meenakshi Ammal Dental College and Hospital, Chennai, Tamil Nadu
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2229-5194.197690

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   Abstract 

This paper describes the importance of accurate diagnosis in the management of complex endodontic cases and highlights the usefulness of cone beam computed tomography (CBCT) in the effective management of challenging cases. This paper discusses seven patients managed for different Endodontic related conditions. The conditions include large radicular cyst, coronoradicular groove, open apex, impacted tooth in an inverted position, mandibular lateral incisor with unusual anatomy (two canals and root concavity), extensive external cervical resorption, and root fractures. In all these cases, CBCT revealed the three-dimensional nature of anatomic and pathologic structures and aided us in following appropriate treatment strategies. CBCT appears to be more reliable than radiographs in the diagnosis and management of complex cases. Since structures can be visualized in different planes, three-dimensional nature of any given object can be studied without any superimposition and distortion. Appropriate utilization of this technology could help in effective patient management.
Clinical Relevance To Interdisciplinary Dentistry
This article discusses several cases with conditions like large radicular cyst, extensive root resorption, open apex, corono-radicular groove, root fractures were managed using cone beam computed tomography with an interdisciplinary approach. The usefulness of CBCT in various dental specialties like endodontics, oral surgery, periodontics were discussed.

Keywords: Cone beam computed tomography, coronoradicular groove, external cervical resorption, root fracture


How to cite this article:
Kowsky D, Naganath M, Kumari A. Endodontic applications of cone beam computed tomography: A series of case reports. J Interdiscip Dentistry 2016;6:80-6

How to cite this URL:
Kowsky D, Naganath M, Kumari A. Endodontic applications of cone beam computed tomography: A series of case reports. J Interdiscip Dentistry [serial online] 2016 [cited 2019 Dec 12];6:80-6. Available from: http://www.jidonline.com/text.asp?2016/6/2/80/197690


   Introduction Top


Cone beam computed tomography (CBCT) is an extraoral imaging system specifically developed for the three-dimensional imaging of the oral and maxillofacial structures. CBCT provides undistorted images free from anatomic superimposition, leading to accurate three-dimensional visualization of anatomic and pathologic structures. Compared to medical computed tomography (CT), CBCT produces clear images with higher resolution and at a relatively lower radiation. [1] Unlike medical CT, CBCT captures data in isotropic voxels, and hence, the object is accurately measured in different directions and remain undistorted in the images. [2] CBCT is useful in visualizing the complex anatomy of tooth including the presence of multiple roots and canals, root curvatures, root concavities and grooves, dens invaginatus. The presence of periapical lesion can be detected at an early stage when compared to radiography. The three-dimensional imaging helps in the detection of root fractures, root resorptions, definitive assessment of periradicular bone support, etc. [3] This article illustrates the usefulness of CBCT images in diagnosis and management of complex and challenging endodontic conditions.


   Case Reports Top


Case one

History and clinical findings

A 32-year-old patient reported to the Department of Conservative Dentistry and Endodontics complaining of pain and huge swelling on the inner aspect of upper jaw. The patient gave a history of trauma to the maxillary teeth about 5 years ago. On clinical examination, a fluctuant swelling was seen on the left palatal area. The swelling was large (approximately, 35 mm anteroposteriorly and 30 mm mediolaterally) and occupied nearly the entire left hard palatal region. Radiographically the lesion appeared to extend from the periapex of lateral incisor to the first molar. The exact extent and outline of the lesion was not clear on the radiograph especially in the posterior region probably because of anatomic superimposition. Maxillary left central incisor, lateral incisor and left canine and left premolars did not responded to sensibility testing (electric and cold). Considering history of trauma and the unclear radiographic extension of the lesion, it was decided to have a CBCT imaging of the involved dento-osseous region.

Cone beam computed tomography findings

CBCT image revealed complete destruction of the buccal and palatal bone along with resorption of palatal and maxillary walls of the left maxillary sinus. No root fracture was seen.

Management

After consultation with an oral surgeon and considering the size of the lesion, it was decided to enucleate the lesion under general anesthesia. Upon initiating the root canal treatment before surgery, drainage occurred through the opened root canals. Following completion of endodontic treatment, surgical enucleation was performed under general anesthesia. Root ends of the involved teeth were resected, prepared, and retro-filled with mineral trioxide aggregate and an immediate postsurgical obturator was placed. Samples from the lesion were sent for histopathological analysis. Histopathology confirmed the lesion to be a long standing infected radicular cyst. Healing was satisfactory with radiographic signs of bony regeneration in the 6 months follow-up [Figure 1]. Patient has been advised to visit regularly for follow-up.
Figure 1: (a and b) Extraoral and intraoral clinical pictures showing the extent of the swelling. (c) Orthopantomograph of the patient. (d and e) Three-dimensional reconstructed buccal and palatal view showing the true extent of the lesion (through and through defect associated with the loss of buccal and palatal bone can be appreciated). (f) Surgical enucleation of the cyst under general anesthesia. (g) Histopathology confirmed a long-standing radicular cyst. (h) Postoperative picture showing satisfactory healing

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Case two

History and clinical findings

A 45-year-old patient was referred for the management of maxillary left lateral incisor which had a deep palatal pocket and bone loss. On examination, it was noticed that the maxillary left lateral incisor had a corono-radicular groove on the palatal aspect starting from the cingulum region. In the adjacent central incisor, there was a groove on the labial aspect of the cervical part of the crown which was extending subgingivally. In both the teeth, apical extent and depth of the groove could not be ascertained clinically. Central incisor was not associated with any periodontal destruction. Sensibility testing suggested the absence of vitality of the lateral incisor and radiograph showed some evidence of mesial interproximal bone loss. Based on the clinical and radiological findings, a diagnosis of palatoradicular groove on the lateral incisor causing localized chronic periodontitis and pulpal necrosis (primary periodontal and secondary endodontic lesion ) and labioradicular groove on the central incisor with vital, healthy pulp was made. It was decided to treat the lateral incisor through a combination of endodontic and periodontal approach. To visualize the three-dimensional extent of the groove and associated bone loss CBCT imaging was performed.

Cone beam computed tomography findings

CBCT images showed that the groove on the lateral incisor extending up to two-third of the root apically. There was palatal and mesial bone loss sparing the apical 4 mm. Radicular extension of the groove on the central incisor was less and confined to the coronal portion of the root and the groove on the central incisor was shallow with a significant amount of unaffected dentin between the base of the groove and the pulp.

Management

Endodontic treatment was initiated and completed in the lateral incisor. In the next phase, restorative correction of the groove and periodontal regenerative surgery was performed. The deepest portion of the groove corresponding to the coronal portion of the root was prepared and restored with chemically cured glass ionomer cement. The apical shallow portion was saucerized and shaped. Periodontal regenerative procedures included curettage, root planning, and placement of osseous graft [Figure 2].
Figure 2: (a and b) Preoperative pictures showing labio-radicular groove on central incisor and palatoradicular groove on lateral incisor. (c) Preoperative radiograph. (d) Sagittal cone beam computed tomography slice showing bone loss surrounding lateral incisor. (e-g) Sagittal and axial cone beam computed tomography slices at different levels showing the pulpward extent of the groove and the associated bone loss. (h) Immediate postobturation radiograph. (i) Full thickness mucoperiosteal flap raised to gain access to the palatal groove. (j) Shallow portion of the groove was saucerized. (k) Deep portion was restored with chemically cured glass ionomer cement. (l) Flap repositioned and covered by periodontal pack

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In this case, CBCT played a vital role in assessing the three-dimensional extent of the groove and the associated bone resorption and helped in selecting the suitable modality of treatment.

Case three

History and clinical findings

A 14-year-old boy was referred by his general dentist for the management of incomplete root formation of the maxillary central incisor. The tooth was symptomatic and radiograph revealed incomplete apexogenesis. The patient had trauma to the facial region when he was 8-year-old. Previous radiographs taken at regular intervals taken by the general dentist had shown no sign of root growth and apical closure. The presence of periradicular lesion was also noticed radiographically in relation to the involved tooth. Cone beam imaging was performed before initiating any treatment.

Cone beam computed tomography findings

CBCT images showed that the periradicular lesion was significantly larger (12.2 mm labiolingually and 9.8 mm mesiodistally) than it appeared radiographically. Interestingly as an incidental finding left maxillary canine was seen in an inverted position and was impacted. The probable reason for the malpositioning of the canine could be the damage caused by the external trauma to the developing dental follicle during odontogenesis. The crown was close to the nasal floor and appeared protruding from the labial cortical bone. The root was seen in the maxillary left second premolar region and was close to the palatal bone.

Management

Considering the young age of the patient and the healing and regeneration potential of the periapex, a biological approach - Revascularization procedure was performed after disinfecting the canal with triple-antibiotic paste mixture. On regular follow-up visits, the tooth responded favorably as noticed by radiographic periradicular osseous regeneration and return of pulp vitality as evidenced by pulp sensitivity testing. The patient is scheduled for follow-up visits to observe further root development and apical closure. The patient was also referred to an oral surgeon for the management of the impacted and inverted maxillary canine [Figure 3].
Figure 3: (a) Radiographs showing absence of root growth and apical closure. (b) Sagittal cone beam computed tomography slice showing the perforation of buccal cortical plate. (c) Axial slice at the apical portion showing the mesiodiatal and buccolingual extent of the lesion (9.8 mm × 12.2 mm). (d) Cone beam computed tomography slice showing inverted and impacted canine. (e and f) Three-dimensioinal reconstructed images, the crown was close to the nasal floor and the root apex was close to the palatal bone

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In this case, an impacted and inverted maxillary canine was observed as an incidental finding. An orthopantomograph would have showed the mere presence of the same tooth, but it is highly unlikely to reveal the spatial relationship of the impacted tooth to the cortical bone, nasal floor (such an information is essential while planning surgical removal of the tooth). CBCT with its three-dimensional imaging modality is capable of providing such vital information.

Case four

History and clinical findings

A 34-year-old male patient was referred by his general dentist for the management of endodontically involved mandibular lateral incisor with periodontal bone loss. On clinical examination, the tooth was slightly discolored when compared to the adjacent teeth and exhibited Grade 1 mobility. The tooth was nonresponsive to vitality testing and was found to be nonvital. Periapical radiograph showed the presence of periapical lesion and bone loss. Focused CBCT imaging was performed to study the internal anatomy thoroughly and to assess the true extent of the bone loss.

Cone beam computed tomography findings

CBCT revealed the presence of two canals in the labiolingual plane. The two canals joined in the apical portion before exiting through a common apical foramen. The lingual canal appeared relatively straight and the labial canal exhibited curvature in labiolingual plane. CBCT also revealed the perforation of labial cortical plate and distal bone loss. Even though the lingual cortical plate was thinned out, it was not perforated. Axial CBCT slices showed the presence of deep distal concavity that resulted in danger zone for endodontic treatment.

Management

Since the tooth had endodontic (primary) and periodontal (secondary) lesion, a combined treatment approach was followed with endodontic treatment being initiated first. Following access preparation, the orifices were relocated slightly mesially away from the distal danger zone using orifice shaper file (ProTaper-Dentsply). The canals were prepared with 2% tapered hand files. Preparation with larger tapered rotary files was not preferred to avoid the occurrence of iatrogenic strip perforation. Following endodontic treatment, periodontal regenerative surgery was performed to correct the periodontal destruction [Figure 4]. In this case, CBCT revealed exact configuration of the root canals, presence of deep distal root concavity and the actual severity of periodontal bone loss thus helping in proper management of the condition.
Figure 4: (a) Preoperative pictures showing the sinus tract associated with mandibular lateral incisor. (b) Preoperative radigraph. (c) Sagittal slice showing two distinct canals joining just before exiting through a common apical foramen. (d) Axial cone beam computed tomography slice showing the presence of two canals and the presence of deep concavity on the distal aspect of the root. (e) Radiographs following completion of root canal treatment

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Case five

History and clinical findings

A 14-year-old boy reported to the department with the chief complaint of discoloration of the front tooth. On clinical examination, distal half of the cervical portion of the labial surface of maxillary left central incisor appeared pinkish. Break in the continuity of the enamel was also noticed in relation to the discolored portion of the tooth. Probing the defect caused intense bleeding. Electric and thermal (cold) pulp testing elicited no response. Radiographic examination revealed the presence of a radiolucent defect on the distal cervical region of the tooth. The defect extended approximately 50% of the radiographic width of the cervical portion of the tooth mesiodistally, and till the middle third vertically. Based on the clinical and radiographic examination, a diagnosis of external cervical root resorption with nonvital pulp was made. It was decided to treat the tooth endodontically and to restore the resorptive defect by reverse sandwich approach as proposed by Vinothkumar et al. [4] In order to see the three-dimensional extent of the resorptive defect, the tooth was subjected to cone beam imaging with limited field of view.

Cone beam computed tomography findings

CBCT showed an aggressive picture of the defect when compared with radiography. In the axial slice, it was observed that the cervical resorption was more than 75% of the cross-section. Sagittal and coronal slices also demonstrated a very extensive defect. CBCT also showed the presence of periodical lesion which was not seen on the periapical radiograph. Axial section also revealed the presence of radiopaque circumpulpal line which was pathognomonic of external cervical resorption [Figure 5].
Figure 5: (a) Clinical picture showing pinkish discoloration of the cervical portion of maxillary left central incisor associated with minute cavitation. (b) Radiograph showing the presence of radiolucent defect on the cervical portion of the tooth. (c-e) Sagittal, axial and coronal cone beam computed tomography slices showing the clear three-dimensional extent of the resorptive defect which was more aggressive than assumed based on radiograph (note: The presence of early apical lesion is well appreciated in the sagittal and coronal slices than on the radiograph)

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Management

After visualizing the true extent of the defect based on CBCT, the tooth was considered to have poor to hopeless restorative prognosis. Hence, the tooth was extracted and was replaced prosthetically.

Case six

History and clinical findings

A 35-year-old male patient reported with chief complaints of pain in the upper front tooth. The patient gave a history of trauma approximately 3 years ago. The involved tooth (maxillary right central incisor) was tender on percussion. The tooth had a ceramo-metal crown. The presence of atypical periradicular radiolucency in the radiograph was noted. Considering the history of trauma and the presence of atypical periradicular radiolucency, it was decided to obtain a CBCT scan of the affected tooth.

Cone beam computed tomography findings

CBCT slices clearly showed the presence of vertical root fracture. In the present case, the presence of vertical root fracture was not seen on the radiograph (presence of vertical root fractures, especially those on the mesiodistal plane cannot be detected by radiographs with high level of accuracy). [5] CBCT images clearly revealed the presence of vertical root fracture and helped to modify and perform appropriate treatment. CBCT also revealed the destruction of labial cortical bone surrounding the central incisor [Figure 6].
Figure 6: (a) Radiograph showing root canal treated maxillary right central incisor associated with periradicular radiolucency. (b) Axial cone beam computed tomography showing the presence of fracture line. (c) Sagittal cone beam computed tomography slice showing the destruction of labial cortical plate. (d) Extracted tooth sowing the presence of fracture line as showed by cone beam computed tomography

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Management

Since any tooth with vertical root fracture has poor endodontic prognosis, it was decided to extract the tooth as early as possible to prevent further periodontal destruction before the development of CBCT, the only conclusive way of detecting vertical root fracture was through surgical exploration. With CBCT, presence of such fractures can be easily detected with high degree of accuracy thereby eliminating the need for unnecessary surgical exploration.

Case seven

History and clinical findings

A 45-year-old patient was referred for endodontic opinion and management of root canal treated maxillary left first molar. The patient had pain on mastication and exhibited tenderness on percussion. Radiograph showed apical curvature on the distobuccal root, and a relatively normal mesiobuccal root, apical termination of obturation appeared to be short of the apex. Some amount of furcal radiolucency was also observed. Based on clinical and radiologic observations, it was decided to perform nonsurgical re-root canal treatment initially as the buccal canals appeared to be obturated much short of the apex. To have a clear picture of the exact degree and direction of curvature of the distobuccal root and also to know the potential reason for endodontic failure, CBCT imaging was performed.

Cone beam computed tomography findings

CBCT images showed the presence of oblique root fracture on the buccal aspect that passed along the distobuccal root [Figure 7].
Figure 7: (a) Periapical radiograph showing root canal treated maxillary left first molar. Distobuccal root had distal curvature and the buccal roots appear to be underobturated. (b) Cone beam computed tomography sagittal slice showing the presence of oblique fracture and the associated furcal and periradicular bone destruction

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Management

Considering the poor prognosis for such a tooth, the tooth was extracted and replaced. In this case, CBCT showed the actual cause for the problem (fracture) which was not seen on the radiographs. CBCT also prevented the initiation of wrong treatment which would have caused further periodontal destruction and persistence of symptoms.


   Discussion Top


Case one demonstrated a large radicular cyst of endodontic origin. Pulp necrosis following dental trauma could be attributed to the pathogenesis in this case. Left untreated, the cyst has attained such a tremendous size. CBCT showed the true extent of the defect including the sinus wall erosion. Case two reported the presence of corona-radicular groove. CBCT revealed the exact vertical and pulpal extension of the groove and helped in determining the appropriate extension of surgical flap reflection and in the selection of restorative material. Case three reported an incidental finding of inverted and impacted canine tooth. In this case, CBCT revealed the spatial relationship of the tooth with vital structures, which is very important during surgical manipulation of such tooth. Case four presented a mandibular lateral incisor with two canals and a proximal concavity as revealed in the axial CBCT slices. Since the proximal concavity posed a danger zone for endodontic treatment, 2% tapered files were used for canal preparation following repositioning of the orifices using an orifice shaper file. Case five demonstrated a maxillary central incisor affected by external cervical resorption. CBCT showed the actual extent of the resorptive defect which was not seen clearly on the radiograph. Even though the initial treatment plan was a reverse sandwich restoration, the tooth was extracted considering the poor prognosis based on the CBCT findings. Case six and case seven exhibited root fracture. In both the cases, the fracture was not evident on the radiographs. CBCT clearly revealed the presence of fracture and the teeth were extracted considering the hopeless prognosis.

Correct diagnosis is essential for proper treatment. Sometimes, the reason for a treatment failure even after meticulous treatment procedures could be failure to identify and address the root cause of the problem. Diagnosis in endodontics is a challenging task, as different conditions may share similar signs and symptoms and same condition may manifest differently in different individuals. Radiographs are essential in studying the hidden anatomic and pathologic structures. At times, radiographs may fail to reveal vital information because of their limitations (two-dimensional representations, anatomic superimposition, distortion, etc.), leading to incorrect diagnosis and treatment.

CBCT is free from most of the limitations of conventional radiography. CBCT has been shown to be more reliable in identifying various conditions such as tooth fractures, resorptions, early periapical lesions, additional roots and canals, iatrogenic damages, and periradicular bone support when compared to radiographs. [6],[7],[8],[9] CBCT may also guide to select appropriate treatment modality. CBCT also provides information regarding the spatial relationship of various vital paradental structures like the inferior alveolar canal and the maxillary sinus, which is very essential while performing periradicular surgeries. [10]


   Conclusion Top


This case series presented a variety of complex cases that were managed appropriately with the aid of CBCT. CBCT is an invaluable tool in the diagnosis of endodontic conditions where clinical and radiographic findings alone fail to provide adequate information. Appropriate utilization of this technology for suitable cases will lead to fewer posttreatment problems and result in more efficient patient management.

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.
Tyndall DA, Rathore S. Cone-beam CT diagnostic applications: Caries, periodontal bone assessment, and endodontic applications. Dent Clin North Am 2008;52:825-41, vii.  Back to cited text no. 1
    
2.
Scarfe WC, Farman AG. What is cone-beam CT and how does it work? Dent Clin North Am 2008;52:707-30, v.  Back to cited text no. 2
    
3.
Patel S. New dimensions in endodontic imaging: Part 2. Cone beam computed tomography. Int Endod J 2009;42:463-75.  Back to cited text no. 3
    
4.
Vinothkumar TS, Tamilselvi R, Kandaswamy D. Reverse sandwich restoration for the management of invasive cervical resorption: A case report. J Endod 2011;37:706-10.  Back to cited text no. 4
    
5.
Bernardes RA, de Moraes IG, Húngaro Duarte MA, Azevedo BC, de Azevedo JR, Bramante CM. Use of cone-beam volumetric tomography in the diagnosis of root fractures. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009;108:270-7.  Back to cited text no. 5
    
6.
Wang P, Yan XB, Lui DG, Zhang WL, Zhang Y, Ma XC. Detection of vertical root fractures by using cone-beam computed tomography. Dentomaxillofac Radiol 2011;40:290-8.  Back to cited text no. 6
    
7.
Patel S, Dawood A, Wilson R, Horner K, Mannocci F. The detection and management of root resorption lesions using intraoral radiography and cone beam computed tomography - An in vivo investigation. Int Endod J 2009;42:831-8.  Back to cited text no. 7
    
8.
Estrela C, Bueno MR, Leles CR, Azevedo B, Azevedo JR. Accuracy of cone beam computed tomography and panoramic and periapical radiography for detection of apical periodontitis. J Endod 2008;34:273-9.  Back to cited text no. 8
    
9.
Zhang R, Wang H, Tian YY, Yu X, Hu T, Dummer PM. Use of cone-beam computed tomography to evaluate root and canal morphology of mandibular molars in Chinese individuals. Int Endod J 2011;44:990-9.  Back to cited text no. 9
    
10.
Meena N, Kowsky RD. Applications of cone beam computed tomography in endodontics: A review. Dentistry 2014;4:242.  Back to cited text no. 10
    


    Figures

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



 

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