Sara Kim
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 HE TOOLS that have advanced the field of endodontics include microscopes, endoscopes, ultrasonic instruments, and the latest addition: Cone Beam Computerized Tomography (CBCT). Traditionally, CBCT has been used by oral surgeons to facilitate implant placement, but now endodontists like us are using it for diagnosis and treatment planning.
CBCT, also known as volumetric imaging, produces a 3D image of the tooth so that you can see many slices in mesiodistal, buccolingual, and cross-sectional views. In endodontics, CBCT can be useful in these situations: finding calcified canals; searching for any missed canals like MB2 (Figure 1), distinguishing between internal and external root resorption and viewing the extent of damage, finding a third canal in a premolar, locating a separated instrument, and preparing for an apicoectomy.
A patient presented with history of intermittent dull pain in the upper right area (Figure 2). He said that he had already taken antibiotics for a week because a sinusitis was suspected, but his discomfort had returned. On the referral form, his dentist had written “root canal treatment of tooth #2” with a big question mark. Upon examination, #2 and #3 were both slightly percussion positive. The cold test of tooth #2 seemed to be normal, but #3 had a very brief delay before the cold was felt. However, the periapical x-ray showed no obvious problems. CBCT was taken, and it showed a small radiolucency around the apex of tooth #3’s palatal root as shown in Figures 3 through 5. When #3 was accessed, the palatal canal was totally necrotic, while MB, MB2, and DB were all vital. After the root canal treatment (Figure 6), the patient’s pain had gone away, and tooth #3 was indeed the culprit. No fractures were noted during the initial examination, but it was concluded that a hairline fracture probably existed in the palatal area thus causing the palatal canal to become necrotic since it was a virgin tooth.
I think CBCT is an extremely useful imaging tool in endodontics. I do not think that scanning straightforward root canal treatment cases is necessary, but CBCT scanning is definitely helpful for those difficult ones. CBCT can only enhance the quality of treatment that we bring to our patients. When you get a disk copy of the CBCT done on your patient, just remember to click on “ODView.exe” to view the 3D images. You will see how easy it is to navigate and how detailed the images are.
July - September 2010
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