3D Imaging with Cone Beam CT Scanners (CBCT)

La Grange, IL – For decades, dentists and dental clinicians have been using imaging to evaluate the condition of a patient’s oral health. While panoramic X-rays have helped dentists a great deal with broader views of jaws and maxillofacial structures, the need for a more advanced radiography has always been felt. The limitations of CT spurred researchers to discover a 3D imaging technique which is cost-effective, accessible and offers more freedom in terms of dose considerations.

Thanks to the advancement in digital dental imaging, dentists now have 3D imaging with Cone Beam CT Scanners (CBCT) at their disposal. This is a technology that has brought a revolution in dentistry.

What is Dental Cone Beam CT?

Cone Beam Computed Tomography (CBCT) is a new-age radiographic imaging method which takes a 3D approach to collect data and reconstructing images. It’s a special kind of scanner which allows dentists to acquire precise, three-dimensional images of maxillofacial or hard tissue structures.

In many dental and orthodontic cases, regular dental and facial X-rays don’t suffice. And the dentist is in need of top quality, sub-millimeter images that make diagnosis more accurate and effective. That’s exactly where CBCT comes into play. This sophisticated imaging modality provides the dentist with a 3D representation of the maxillofacial structures while cutting down the scanning time by a significant margin. CBCT has also resolved the issue of dose consideration; radiographic exposure dose from CBCT is a drastic 10 times less than that of traditional CT scans and the dimensional accuracy of CBCT is far greater. The CBCT technology has arrived as a boon for dentists and dental clinicians on a worldwide level.

How the CBCT Technology Works

The CBCT imaging technique involves the direction of a cone-shaped beam of ionizing radiation through the center of the target area onto an X-ray detector positioned on the opposite side. Imaging is performed with the use of an X-ray source and detector that rotate around the patient’s head.

As the X-ray source and the detector move around, a series of single projection images are captured at specific degree intervals. Termed as ‘basis’ images, these images count anywhere between 150 and 600 (or more). All the images together form a sequence, which is known as projection data. Next, these sequential images are used to create a 3D image representation with the help of a third-party software program. In CBCT, only one rotational sequence of the gantry provides adequate data which can be used to reconstruct images. Finally, the dentist has a three-dimensional volumetric data set which gives them a comprehensive view of the maxillofacial structure on axial, sagittal and coronal plane.

In a traditional CT scan, a fan-shaped beam is directed in a spiral progression to capture separate image slices of the field of view. Then, these slices are arranged to create a volumetric representation. The one-scan-one-slice process prolongs the time of scanning. But CBCT is much quicker because loads of data for reconstruction of images can be gathered in one rotational sequence.

Dental cone beam CT is a revolutionary substitute for traditional CT. The CBCT X-ray machine is small in size and cost-effective to have. Most of all, CBCT can be easily installed in a dental office.

Applications of Cone Beam CT Scanner (CBCT)

CBCT has emerged as the most preferred imaging modality to be used in dentistry. This advanced scanning technology is mostly leveraged to detect and evaluate bony and dental pathologies. With the help of CBCT, orthodontists and dental clinicians can easily locate benign or malignant tumors, fracture and different kinds of deformity in the maxillofacial structure. If a person has an impacted tooth and is unaware of it, a CBCT can quickly detect it. In case of an implant, CBCT helps orthodontists find out how much bone is exactly available.

CBCT is not just an imaging method that helps with the accurate diagnosis of various dental conditions. In fact, it is a technique which has introduced image-guided surgery in the field of dentistry.

If a dental implant or a surgical procedure is what a patient needs, CBCT can help the orthodontist analyze the case on a deeper level and then come up with a detailed treatment plan based on the insights. Common applications of CBCT include surgical planning for impacted teeth and dental implants, diagnosis of TMJ disorder, accurate positioning of dental implants etc.

Conventional 2D imaging is limited in its scope to determine the presence of lesions in its early stage. But the CBCT technology has made it easier to detect root resorption almost as soon as it starts to develop.

CBCT scan has found an important application in implant dentistry, as mentioned in the above paragraph. Using this imaging modality, orthodontists can effectively plan and guide the surgical procedure in a dental implant. Whether it’s about selecting cases or achieving greater precision in an dental implant surgery, CBCT scanning has proved to be of massive help. In fact, CBCT imaging allows the orthodontist to preview the end result of a dental implant before the surgical procedure initiates. Above all, the insights gained from the CBCT scan minimizes the possibility of structural damage during a dental implant surgery.

In the same way, the 3D imaging feature of CBCT has proven its usefulness in treating temporomandibular joint (TMJ) disorder by helping orthodontists precisely measure the roof of the glenoid fossa and then figure out surrounding the TMJ without the need for magnetic resonance imaging.

3D imaging with cone beam CT scanners has effective application also in the field of periodontics and forensic dentistry.

The Shape of the Equipment

CBCT scanners are small, square-shaped X-ray machines. The machine allows patients to get scanned either in a sitting position or lying down. The orthodontist will guide you about how to sit in the upright chair or lie down on the table so that the scanning can be done in an effective manner.

Though scanning is most comfortable in a sitting position, the fixed seats can make it difficult to scan wheelchair-bound patients. Scanners that include a table for lying down are comparatively larger and so they take up more space. CBCT scanner with a chair features a C-arm, an X-ray source and the detector whereas the one with a table has a rotating gantry attached to it.

How to Prepare for a Dental Cone Beam CT Scan

There are no specific guidelines or advance preparation that you need to do before a CBCT scan. However, there are some objects that might hinder the imaging process and so you’ll be asked to remove them. For example, items of jewelry, glasses and hair pins may have to be taken off. If you are an orthodontic patient with removable dental work, it certainly has to removed.

There are some considerations in regard to a CBCT examination for pregnant women. Usually, a small dose is delivered to the abdomen of a patient and so there’s no reason to get worried or panicky if you are a pregnant woman. Still, you should inform your orthodontist about your pregnancy.

If your dentist or dental clinician is conducting a CBCT scan to do surgical planning for a dental implant, you’ll be asked to put on a scanning appliance, which is a small equipment worn in the same way as dentures.

Duration of a Dental Cone Beam CT Scan

The scan time for a CBCT is very brief. A complete CBCT of the mouth can be done merely between 20 and 40 seconds. If just a small section needs scanning, it takes 10 seconds or even less.

As soon as the scanning is over, you can return to your normal daily life and eat and drink as per your liking.

Key Benefits of CBCT at a Glance

Above, you have read about the benefits of using CBCT scanning in dentistry. Here’s a quick re-look at the key advantages.

Refined Diagnosis: Early and appropriate diagnosis is crucial in all health conditions. 3D imaging with cone beam CT scanners has gained popularity for the accurate diagnosis it has to offer in endodontics, periodontics and orthodontics. Dental clinicians use it both for precise diagnosis and predictive treatment.

Effective Treatment Planning: The insightful data gathered through 3D imaging with cone beam CT scanners helps the orthodontist effectively plan out an orthodontic treatment and guides the entire surgical procedure.

Quick Scan Time: Unlike a traditional CT scan, a CBCT scan is much faster and can be performed within a few seconds. However, the image reconstruction for a volumetric 3D representation can take 1-20 minutes.

High-Resolution Images: CBCT imaging produces images that have a sub-millimeter resolution, which enhances accuracy of measurement in a wide range of maxillofacial applications, particularly in dental implants. High-resolution images make it easy to achieve precision in orthodontic analysis.

Reduced Radiation Dose: Though the effective patient radiation dose varies from one FOV CBCT equipment to another, the CBCT technology has made it possible to use small doses. Compared to a normal CT scan, the radiation dose for a CBCT scanning is considerably smaller.

Small Size: Compared to the size of a conventional X-ray machine, a CBCT machine is much smaller. Measuring only 7 feet in height and 400 lbs in weight, this scanner can be easily set up in an outpatient clinic.

CBCT is fast transforming diagnosis and treatment in dentistry. More and more dental practices are embracing this advanced technology to provide the best dental care possible to orthodontic patients. As this new 3D imaging with cone beam CT scanning technology evolves more, you can expect further reduction in scan time. If you have any questions regarding CBCT scanning, feel free to send us an email or give us a quick call and we’ll explain it for your understanding.

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