CBCT in the Periodontic Practice

cbct

The potential advantages of cone beam computed tomography (CBCT) to periodontology are fairly well known. Implementing a CBCT system into your practice can: streamline the workflow; enhance diagnostic techniques and treatment planning; hone surgical anatomic expertise; and improve outcomes in specific implant and periodontal cases. But because CBCT is a relatively new technology, there’s little evidence-based everyday guidance for the periodontist to rely on. In the absence of this information—and because CBCT technology is so promising—the American Academy of Periodontology (AAP) used a model of scientific inquiry called best evidence consensus (BEC). BEC is based on the best available current published evidence, as well as expert opinion, and serves as a guide for reasonable uses for CBCT in selected clinical scenarios. In this blog, I would like to highlight several key points from my paper in the Journal of Periodontology, Commentary: Cone-Beam Computed Tomography: An Essential Technology for Management of Complex Periodontal and Implant Cases, regarding the use of CBCT in for three different clinical situations. Continue reading

Interpreting Advanced Imaging: It’s Best to Know Nothing

by John Khademi, D.D.S, M.S.

Interpreting advanced imaging, such as CBCT imaging, is tricky. Evidence of just how tricky becomes apparent during lectures I give on the subject. I will show a study to the audience and discuss it for several minutes. When I take it down, I ask them which side was buccal? Which side was palatal? Was it tooth number 14 or number 3?

The audience will start guessing, because they really don’t know—even after looking at the tooth for 5-10 minutes. They would never mistake buccal for palatal, or the tooth numbers, with 2D radiography. But with 3D radiography, it happens all too often. I’ve been evaluating 3D imaging everyday in my endodontic practice for eight years now, and I can still make this kind of mistake. The issue is this: we don’t have that same set of skills with 3D radiography that we do with 2D radiography, but we think we do.

In medical radiology, however, they’re well aware of the complexities that go along with interpreting imaging. That’s why medical radiology is a four-year specialty after medical school—with sub-specialties after that. You don’t want a mammographer evaluating the CT of your head or a thoracic radiologist reading your mammogram.

The need for specialization is clear: interpreting 3D imaging calls for a well-trained eye. That’s why we have to be very careful when we interpret with CBCT. For this reason, I’ve developed a strategy for interpreting 3D imaging based on what has been learning in medical radiology.

It’s important to note that I don’t automatically order an imaging on every patient. Whenever possible, my staff provides me with the minimum information necessary to determine if an advanced imaging study should be prescribed.  This very counter-intuitive finding is captured in the title of a 2002 paper in Radiology from noted radiologist Dr. Thorn Griscom: A Suggestion: Look at the Images First, Before you Read the History.”

Whenever possible, the preferred method involves doing two reads—first, without looking at the projection radiograph, doing a clinical exam or talking to the patient first about their symptoms or getting the history. My goal is to not have any preconceived notions about what the findings may be, let alone the diagnosis. Of course, with CBCT—especially with the focused field—if it’s an upper left side, I have a pretty good idea of where the problem is. But that’s all I really want to know.

I evaluate the study through that lens. I then get the history, look at the projection radiograph, review all the clinical information and perform the clinical exam. After that, I go back and look at the CBCT study again. This approach is very counterintuitive and not widely appreciated.  Current recommendations for approaching are as follows: conduct a thorough clinical exam and radiographic exam before prescribing imaging. In my opinion, that’s backwards, and not based on what has been learned about the interpretive process through careful research in medical radiology. Continue reading

CBCT at Its Best: Get Involved

Dr. Kunal Shah is the Principal of a new practice in Hendon, London – LeoDental. With a state-of-the-art CBCT installed, the practice is receiving referrals for implant planning cases. Completing his series of articles looking at the use and benefits of CBCT in implant treatment, Kunal explores where dentists can start when getting involved with implantology, highlighting the importance of mentorship.

Unlike other areas of dentistry, there is no clear path to follow when looking to get involved in implantology. It is often down to the individual to seek the appropriate training through courses and postgraduate qualifications that satisfy the GDC’s requirement for implant dentists to be competent in the field.

When looking for an initial training course, I would recommend asking the following questions in order to overcome some of the hurdles I faced:

  • What does the course entail? What do you gain at the end of it? – You need to establish whether you’re looking for a qualification or clinical experience, as this will determine what type of training you chose. The qualification courses tend to be the MScs and Diplomas, which are heavily theory-based, while others are more clinical and practical-based. I personally preferred the clinical element – as a dentist, you already have knowledge of the anatomy, so implantology is simply building on this. I also believe you need practical experience to develop your skills, learn from your mistakes and understand the different scenarios that can occur in practice. Continue reading

CBCT at Its Best: In Practice

Dr. Kunal Shah is the Principal of a brand new practice in Hendon, London – LeoDental. With a state-of-the-art CBCT installed, the practice is receiving referrals for implant planning cases. In the second instalment of his three-part series, Kunal demonstrates a clinical case study where CBCT scanning was integral for predictable treatment and the very best outcome for the patient.

Background

A female 52-year-old patient was referred to me from a local practice for implant surgery. I had developed a good rapport with the referring dentist, who was looking for mentorship through this case. The patient had had missing teeth for several years (15-20), although this had only recently begun affecting her lifestyle as she had issues eating – the problem was therefore functional rather than aesthetic.

The patient was fit and healthy, with no relevant medical background or allergies, a non-smoker, social drinker, moderate previous dental restorations and generally good oral hygiene. The LL6, LL7 and LR6 were missing, having been extracted many years ago. The adjacent teeth had started to drift and the opposing teeth on the other side were erupting.

The treatment options were discussed with the referring dentist and the patient, which included no treatment, bridges, dentures and implants. The patient wished to proceed with implants and consent was obtained. Continue reading

CBCT at Its Best: The Perks

Dr. Kunal Shah is the Principal of a new practice in Hendon, London – LeoDental. With a state-of-the-art CBCT installed, the practice is receiving referrals for implant planning cases. As part of a three-part series, Kunal begins by considering the treatment pathway for implant treatment and how CBCT imaging improves the process for a more predictable outcome.

As implant dentistry continues to increase in popularity among the profession and patients, it’s important to establish a protocol for consistently safe and effective treatment. The quality and type of imaging used during the assessment and planning phases has a huge influence on this. In particular, the cutting-edge CBCT scanners now available offer unprecedented visualisation of each patient’s anatomy for precise planning and predictable outcomes.

For dentists new to dental implantology, the standard treatment pathway is as follows: Continue reading

Implants and CBCT

It is no longer a debatable fact that three-dimensional imaging is standard of care when it comes to the surgical component of implant placement.1 The key here is to understand the value of achieving the three-dimensional view, simply phrased as the depth component of the visual anatomy. CBCT images are valuable to understand the topography and—more importantly—the inner component of the osseous structures.

Although all the image stacks are very critical to forming an opinion of the anatomical region in consideration, it is the cross-sectional view that are the most used when it comes to virtual planning of implants. Surgeons are better able to appreciate the buccal-lingual dimension of the bone when viewing the cross sectional reconstruction of the scanned anatomical area of the jaws. While viewing this reconstruction and other multiplanar images, there are some key anatomical markers to be evaluated as a part of the visual assessment of the bone.

It is expected that the morphology of the edentulous areas varies not only between individuals, but in an individual’s oral cavity. Age is a critical factor in the change noted in the osseous structures. Another critical factor is time; the longer a patient stays edentulous, the more the probability of resorption of the alveolar crest. This leads one to note the following three (not limited to) critical changes in the jaws:

Examples of lingual undercut, knife edge ridges and ridge angulation. Continue reading

Five Things to Consider When Purchasing a CBCT System

The decision to add a CBCT system to your practice is a big one, largely because of the capital required. It isn’t like integrating a new laptop or tablet into your workflow. This kind of investment calls for careful consideration—particularly in five areas.

1.      Image resolution. The most important aspect of all: high image quality. Increasing your diagnostic capabilities is the number one reason to integrate CBCT technology into your practice in the first place. You need to be able to see your area of interest with unprecedented detail. But you also need to be able to adjust image quality with dose—so options for field of view are important.

2.      Versatility. What if you invest in CBCT imaging today and—six months down the road—you decide you want the ability to do cephalometric scanning? It would be nice to have a system that could expand with your capabilities, instead of having to purchase a whole new system. You should be able to take advantage of updates to your system when they become available, like for airway analysis, integration with CAD/CAM or low dose imaging. Continue reading

Atypical Anatomy: Tips on What to Look for in CBCT Data

While most of the scans you read will fall into the “normal anatomy” category, the logical next step in the journey of learning how to interpret data sets from cone beam computed tomography (CBCT) imaging is developing proficiency at deciphering anatomical variations. These variations can often be seen in intraoral and extraoral radiography, and it is sometimes helpful to use 3D radiography to fully understand certain variations; which otherwise could result in failure to diagnose.

One of the most common anatomical variations of a critical structure is the anterior extension/loop of the inferior alveolar nerve. Visualizing this structure is imperative when planning surgical procedures in the anatomical areas around mental foramen and the immediate area anterior to it.

Anterior extension of Inferior Alveolar canal: the red circle shows anterior extension and the yellow circle shows mental foramen

In addition to mental foramen, accessory foramen(s) can also be noted as a variation of normal anatomy in the mandible.

The temperomandibular joint (TMJ) area can exhibit wide variations in normal anatomy, which has to be correlated with clinical findings and additional imaging if necessary to establish the absence of any pathology. One of the most common variations can be the inter-articular space of the joint. This space may vary widely between contralateral joints of the same patient and between patients as well. The complexity of this anatomical region warrants a thorough review of all information available. Continue reading

The Importance of Knowing Normal Anatomy in CBCT Scans

The acquisition of CBCT scans is probably one of the most mundane tasks, but it is an important part of the imaging process. Post-acquisition involves viewing and interpreting the scans. Although the maxillofacial region is complex, by virtue of familiarity, most dentists can interpret this area very efficiently despite the complex nature of anatomy and variances in this region. Understanding what is considered normal is the first step to identifying abnormalities that could pose a challenge in the treatment planning.

Normal anatomy can be broadly divided into the maxillary and mandibular regions.

When visualized, the upper regional anatomy is comprised of (but not limited to) the bilateral maxilla, as well as the nerves and vascular supply of the region and the maxillary sinus and other paranasal sinuses (in part or full, depending on the field of view). Along with these areas, the, Osteomeatal complex and orbits are the most significant.

Maxilla- Coronal View of Bilateral Maxillary Sinus

Maxilla- Coronal View of Bilateral Maxillary Sinus

Continue reading

Which Field Of View Is Right For You?

If you are wrestling with the idea of adding a new 3D imaging system to your practice, there are a few questions you should ask yourself:

  • What do I want to do with the information that the new system will provide?
  • Am I interested in return on investment (ROI)? (Of course you are, but is there more to it than that—like broadening your skills as a clinician?)
  • Am I expanding the capabilities of my practice in the future?

How you answer these questions can help you determine which field of view (FOV) is right for you and which imaging system best fits your needs.

What Do You Want to Do?
Is it endodontics? Implants? Airway analysis? Orthodontics? The following table can help you determine what to look for in an imaging solution.

Field of View
Small FOV
(5cm x 5cm)
Medium FOV
(8cm x 9cm)
Large FOV
(up to 17 cm)
Goal
Endodontics
View one or two teeth at a time
X X
Implantology
Scan single and dual jaw; perform guided surgery
 

X

X
Oral surgery
Evaluate: trauma cases; TMJ disorders; airway/sleep apnea disorders
X
Periodontics
(including, but not necessarily only implants)
 

X

 

X

Orthodontics
Evaluate: ectopic and impacted teeth; third molars
X X X
Assess TMJ, skeletal symmetry X
Airway
Evaluate airway, sleep apnea
X

 

Is Your Objective ROI?
If you are considering a shift to in-house imaging, ask yourself how many times per month you refer patients out for a scan. If your average is four or more, it may make sense to invest in a cone beam computed tomography (CBCT) imaging system. In about a year or less, your system could pay for itself.* Continue reading