Cone Beam Imaging for Endodontists: A Review of Clinical Applications

Today’s endodontists have all the benefits of historically significant statements and research, provided that they choose to take advantage of it. This is clearly illustrated taking into consideration the published images of Walter Hess in 1924¹, Schilder’s admonitions of 3-dimensional cleaning and shaping in 1967², as well as present day CT analysis of root canal systems and dental anatomy by Brown and Herbranson in the tooth atlas³. Each one of these citations makes reference to three dimensions when we are evaluating endodontic anatomy.⁴

While it may be considered “overkill” to utilize cone beam volumetric imaging (CBVI) in our evaluation of the endodontic complex⁵, in reality, “Why shouldn’t we?” Who would not want to see as much as we can see? Who would not want as much information as possible? Who would not want to have all available information prior to a clinical procedure? While we have known for some time that root canal systems were 3-dimensional, it has not been until relatively recently that we have the technology to let us visualize 3-dimensional dental anatomy on a live patient.

Cone beam technology has captured the attention of the endodontic community. Some endodontists have likened CBVI to the introduction of the dental operating microscope.⁶ Some see it as the next quantum leap in imaging science in endodontics.⁷ With the passage of time some predict that it will become standard of care for the diagnosis and treatment of endodontically compromised teeth.⁸ Regardless, CBCT is here to stay. It has clearly been adapted by the dental community, and even more quicker than digital radiography itself.

There are four primary areas in today’s endodontic practice that can implement CBVI on a regular, if not daily, basis. Specifically but not limited to these four areas, is the evaluation and diagnosis of:
1. untreated teeth
2. non-surgical retreatment
3. surgical retreatment
4. implant treatment planning and placement.

More than one clinician has recommended taking additional off-angle periapical images (digital or conventional) during the diagnostic appointment when evaluating a suspect tooth for possible endodontic therapy.⁹ In my opinion, without CBVI, this should be done routinely in a thorough endodontic diagnostic examination.With access to CBVI, it is possible that so much valuable information is obtained from the 3D image that additional off angle periapical images may not be necessary.

While CBVI was first introduced to the dental marketplace in 2001,¹⁰ the more recent development and release of machines capable of small-volume-size data acquisition make CBVI even more attractive to endodontists. Early machines were relatively large, taking up valuable space, and necessitated the acquisition of a large volume of data. These early machines were expensive and primarily utilized by imaging centers, research institutions, and universities. The specialty of endodontics does not require that we see all of the head and neck anatomy that these early machines provided. In addition, the quality of the images and the resolution did not make the data invaluable to an endodontist. The smaller volume size and targeted region of interest (ROI) that some of the newer machines provide are especially useful to the endodontist. And, not to be taken lightly, the radiation exposure is significantly reduced with the smaller volume machines.

Several tools available in CBVI will never be available for conventional or even digital radiographic assessment. These include: changing the vertical or horizontal angulation of the image “on the fly”; that is, in real time, as well as thin slice, gray scale data of 0.1 mm thickness. In addition, the ability of CBVI to allow visualization of the suspect tooth in 3 anatomic planes of section, at very low radiation doses, was never as easy as it is now.¹¹

At last count, close to two dozen dental cone-beam imaging systems were being marketed today in the dental arena. Evaluating a particular system can be overwhelming, for even the most discerning clinician. There are several criteria that an endodontist must seriously consider when evaluating the purchase of a CBVI machine. These include:

1. Volume Size
2. Reasonable footprint
3. User Friendliness
4. Multi-functionality
5. Technical Support
6. Known Manufacturer
7. Affordability
8. DICOM compatibility

Clinical Case

Figure 1

This patient presented with a previously treated upper left first permanent molar. The tooth had been treated endodontically approximately twelve years previously but the patient had never been pain free in the maxillary left quadrant. (Figure 1)

Figure 2

The patient was given treatment options and did not elect to have treatment at that time but returned approximately fourteen months later. An updated periapical digital image was taken at that time. (Figure 2)

Figure 3

For the first examination consultation appointment we did not have 3D imaging technology in place. At the time of the second consultation the cone beam system had been installed and we were using it regularly beginning to find it especially useful in endodontic retreatment cases. A panoramic and 3D image was taken. (Figure 3)

A single slice of one of the 3D images shows a significant lesion of endodontic origin in each plane of section axial, coronal, and saggital. What appears to be vague on a digital periapical image is clearly significant with 3D imaging technology. The advantages of using 3D imaging technology for endodontic diagnosis cannot and should not be overlooked.

Reference

1. Hess W (1925) Anatomy of the root canal of teeth of the permanent dentition. London, J. Bale, sons & Danielsson, ltd.
2. Schilder H (1967) Filling root canals in three dimensions Dent Clin North Am 723-744
3. Brown D. Herbranson E. (2009) ‘Tooth Atlas 5.1 Demonstration Video’, n.d.,(29 January 2009)
4. Schilder H (1974) Cleaning and shaping the root canal Dental ClinNorth Am. 18:269-296
5. Buchanan L S (2009) (April) The dawning of 3D endodontic practices Endodontic Practice US 12-15
6. Buchanan L S (2009) Ahead of the Curve Future Directions in Endodontics
   Dentistry Today (April) 110-116
7. Carr G (2009) Focused Field CBCT Correlative Anatomy Study Proposal PERF
8. Ruddle C (2002) Endodontic Diagnosis Dentistry Today (October)
9. Miles D. Danforth R. (2007) A Clinician’s Guide to Understanding Cone Beam Volumetric Imaging Academy of Dental Therapeutics & Stomatolgy Special issue 1-13
10. Miles D. (2008) Color Atlas of Cone Beam Volumetric Imaging for Dental Applications
11. Miles, D (2008) The Future of Dental and Maxillofacial Imaging Dental Clin North Am 52 917-928.