facebooktwittermyspaceblog

 

The Cone Beam Computed Tomograpy device, or CBCT, is perhaps the most exciting and indispensible piece of armamentarium in Endodontics since the Surgical Operating Microscope (SOM). With the introduction of the SOM into clinical practice, the increase in magnification revealed a dimension that both awed and humbled the most experienced practitioner, and raised expectations as to what could now be achieved via conservative treatments. The only shortcoming to this process was the reliance on a two-dimensional image (conventional radiographs) to formulate a three-dimensional treatment plan. Often the patient’s complaint and presentation were not matched with the appropriate radiographic representation, confounding the diagnosis and complicating subsequent treatment decisions. In extreme instances, invasive procedures (surgery) were employed to “explore,” via direct visualization, the areas in question in the hope of discovering the definitive cause of the presenting symptoms.

 The necessity to resort to these means has been substantially diminished with the implementation of cone beam computed tomography (CBCT). CBCT was introduced to the maxillofacial profession in 1996, but was not approved for dental use until 2001. These earlier units produced a large field of view (FOV) and a low-resolution scan, but contemporary models offer a smaller FOV (as small as 50 mm x 38 mm) with slice thicknesses of .076μ.

 The most pivotal feature is the ability to render a perspective view of an area of concern from three main directions and, through axes alterations, an infinite number of diagnostic views. This technology allows us to perform Virtual SurgeryTM on the displayed image, narrowing our focus and streamlining the decision tree for diagnosis and treatment. The feasibility of a re-treatment is more accurately ascertained without the invasiveness of clinical disassembly, sparing both the patient and practitioner undue time and expense. Pathology not readily apparent on conventional radiographs is defined with remarkable clarity because its presence is not camouflaged by bone thickness or overlying structures. A recent study reported that the CBCT showed 34% more lesions than conventional

                               

 (All images taken from the presentation "CBCT: The Virtual SurgeryTM in Endodontic Treatment Planning" )

radiographs of the same site. Incipient disturbances in the periodontal ligament space can often be demonstrated because the slice thicknesses are one-half the dimension of the PDL (0.2 mm). This aspect is instrumental in diagnosing vertical root fractures where the fracture line cannot be visualized, but its distinctive disruption of the ligament space is glaringly apparent.

The radiograph on the left illustrates this point dramatically. The patient had presented with biting sensitivity after the crown had been placed some months before. The tooth was originally restored with a full-coverage restoration because the patient had fractured a significant portion of the buccal portion of the tooth. There were no notations of any fracture being present during the delivery of the final crown, and the patient was referred for endodontic consult / treatment.

 

    

The examination revealed deep pocketing at the distal aspect, but no suppuration or overt mobility. However, when examining the CBCT, it became readily apparent that the tooth was vertically fractured from the mesial, through the furcation, and terminated at the distal aspect of the CEJ. The tooth was deemed hopeless, and the patient was directed to have the tooth extracted. Previous to this technology, the patient may have had to undergo an exploratory surgery which, even then, may not have uncovered the cause due to the location of the fracture.

I invite you to the office to appraise this new technology for yourself, or you can visit the Carestream (formerly Kodak) website to learn more about this exciting aspect of endodontic practice! 

 Back to Procedures