Indian Journal of Dental Research

: 2014  |  Volume : 25  |  Issue : 1  |  Page : 99--101

Cone beam computed tomography: A tool for the diagnosis of confusing periapical lesions in conventional radiographs

Luciana Maria Paes da Silva Ramos Fernandes, Camila Lopes Cardoso, Izabel Regina Fischer Rubira-Bullen, Ana Lucia Alvares Capelozza 
 Department of Stomatology, Bauru School of Dentistry, University of Sao Paulo, Bauru, Sao Paulo, Brazil

Correspondence Address:
Luciana Maria Paes da Silva Ramos Fernandes
Department of Stomatology, Bauru School of Dentistry, University of Sao Paulo, Bauru, Sao Paulo


We report two cases in which cone beam computed tomography (CBCT) was essential for the establishment of the diagnosis of periapical lesions. CBCT allows a three-dimensional assessment of a specific region with no superimposition of structures. Therefore, its use is recommended when radiographic images are not sufficient for the diagnosis.

How to cite this article:
Fernandes LR, Cardoso CL, Rubira-Bullen IF, Capelozza AA. Cone beam computed tomography: A tool for the diagnosis of confusing periapical lesions in conventional radiographs.Indian J Dent Res 2014;25:99-101

How to cite this URL:
Fernandes LR, Cardoso CL, Rubira-Bullen IF, Capelozza AA. Cone beam computed tomography: A tool for the diagnosis of confusing periapical lesions in conventional radiographs. Indian J Dent Res [serial online] 2014 [cited 2021 Oct 16 ];25:99-101
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Full Text

Dental radiographs are bidimensional projections of a tridimensional structure, and therefore, superimposition of anatomic landmarks can masquerade important findings. [1],[2],[3],[4],[5],[6],[7],[8],[9],[10] Cone beam computed tomography (CBCT) is an advanced technology that allows the tridimensional assessment of the region of interest by means of reformations in sagittal, coronal, and axial views. [2],[3],[4] CBCT is an useful tool for the diagnosis of confusing lesions that cannot be properly assessed in dental radiographs. The aim of this article is to report two cases of persistent periapical lesions that presented confusing radiographic images as well as to discuss the benefits of CBCT images for the elucidation of both cases.

 Case Report

Case 1

A 31-year-old female was referred to our stomatology clinic complaining of "gingival lump." The symptomatic lesion had been observed 2 months before. Her dentist sent us a letter in which assessment and treatment of the region were required. The initial hypothesis suggested by her dentist was buccal exostosis. During clinical examination, we observed a symptomatic nodular lesion, firm to palpation and covered by normal mucosa, located in the buccal region of apex of right maxillary first premolar (tooth #5) [Figure 1]a. Two periapical radiographs were then performed with different horizontal angles of exposure. The related tooth was root-filled, but no significant change was clearly seen in the periapical region [Figure 1]b. Considering that more information was necessary for the diagnosis establishment, a CBCT scan was done on a Classic i-CAT unit (Imaging Sciences International, Hatfield, PA, USA) using 8 cm field of view (FOV) and 0.3 voxel size. During assessment of transversal views, hypodense images suggestive of periapical lesions and absence of endodontic filling material inside the root canal were observed [Figure 1c]. Cortical bone resorption was also observed [Figure 1]d and 1e]. The patient was then referred for endodontic retreatment of tooth #5.{Figure 1}

Case 2

A 28-year-old male attended our stomatology clinic complaining of pain in the left side of his face. The patient did not present any temporomandibular joint disorder or othorrinolaryngologic and neurological disturbances. During clinical examination, no swelling was observed and the oral mucosa was normal. Then we performed panoramic and periapical radiographs of the left maxillary premolars and molars in order to detect any possible cause of the pain. His left maxillary first molar (tooth #14) was endodontically treated and presented a metallic crown [Figure 2]a. Considering that a possible radiolucent image related to tooth #14 was confusing in radiographs, we decided to do a CBCT scan on a Classic i-CAT unit (Imaging Sciences International, Hatfield, PA, USA) using 6 cm FOV and 0.3 voxel size. In CBCT images, it was possible to detect periapical lesion related to a mesiobuccal root canal with no root filling of the tooth #14 [Figure 2]b and c.{Figure 2}


In both cases, the diagnosis of periapical pathology was difficult to establish. In the first case, buccal exostosis was the initial hypothesis considering clinical aspects of the lesion. However, most part of buccal exostosis is asymptomatic when covered by normal mucosa. CBCT was fundamental for the periapical lesion visualization, which was not clearly seen in periapical radiographs. The compromise of cortical bone was evident [Figure 1]d and e, even though Bender [1] stated that a periapical lesion, which affects cortical bone, can be usually seen in conventional radiographs. Also, CBCT images allowed a critical evaluation of the related endodontically treated tooth condition. It was possible to relate the incomplete root canal filling with the failure of the endodontic treatment and consequent persistent periapical lesion. [11]

In the second case, the diagnosis establishment was also challenging. The patient had facial pain and medical doctors had not detected its cause. CBCT images allowed the mesiobuccal root canal to be properly assessed, especially in axial view. The absence of root canal filling material allows the maintenance of microorganisms inside root canal systems, which can lead to persistent periapical lesion. [11] Since this lesion did not compromise cortical bone, its visualization was confusing in periapical radiographs. [1] Also we could identify a hypodense image inside maxillary sinus related to the affected tooth, which can indicate an inflammatory reaction of the sinusal membrane due to the persistent dental infection.

Although periapical lesion is a common finding in odontology, its detection can become challenging for the clinician, especially in root-filled teeth. [6] Clinical presentation or image appearance alone is not sufficient for the diagnosis of the radiolucent lesions. [12] It is important to combine both diagnosis resources in an effective way. A study showed that CBCT allowed 38% more periapical lesions to be detected than with conventional radiographs. [2] Tsai et al., [5] observed that periapical radiograph demonstrated poor diagnostic accuracy for small simulated lesions, whereas CBCT demonstrated good accuracy when simulated lesions diameter was more than 0.8 mm. CBCT accuracy is also superior when compared with the combination of two radiographic exposures for the detection of simulated lesions. [8] Therefore, the literature confirms that CBCT is an effective tool for the diagnosis of periapical lesions.

It is important to mention that CBCT generates a higher radiation dose for the patient in comparison to periapical radiographs. [10] Therefore, the ALARA (As Low As Reasonably Achievable) principle must be considered. CBCT is recommended when more information is required for the establishment of the diagnosis and treatment plan, especially for persistent periapical lesion that requires a complex endodontic approach. Also, CBCT allows the professional to differentiate periapical pathology from other conditions.


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