Even though cone-beam computed tomography, or CBCT, has been sold in the United States since the early 2000s, this technology is still a relatively new concept. At pH Dental, we encounter the following questions regarding CBCT from dentists every day.
- Does cone-beam CT offer anything different than traditional fan-beam CT?
- Are there any limitations when using CBCT?
- What are the advantages of this device?
- How is the radiation exposure when taking CT scans?
- Is owning a CBCT profitable in the long run?
Yes, we understand that it is not easy to decide on investing in a cone beam machine, as a new device could cost as much as $100,000. However, we do believe that investing in a CBCT machine is a must. It is not even an option. In this article, we are going to explain what CBCT is, and what are the advantages and disadvantages of CBCT in dentistry.
What is CBCT?
CBCT is a variation of traditional computed tomography (CT) systems. In conventional CT scanners, an x-ray tube that emits a finely collimated fan-shaped x-ray beam directed through the patients to a series of scintillation detectors. The detectors form a continuous ring around the patient, and the x-ray tube moves in a circle within the fixed detector ring, taking 2D images. 3D images can be created by stacking all 2D slices together.
On the other hand, in CBCT systems, the x-ray tube and detector panel rotate around the patient. The data is captured by an x-ray beam shaped like a cone or a pyramid (unlike the fan-shaped beam in traditional CT), thus giving the technology the name cone-beam computed tomography. During the scan, CBCT captures 150-600 distinct sequential planar images, which are then reconstructed using algorithms to produce 3-dimensional images. The 3D images provided by CBCT can be viewed in either axial, coronal, or sagittal planes. Additionally, these images are in the DICOM (Digital Imaging and Communications in Medicine) data format, enabling dentists to telecommunicate the imaging information.
Advantages and Disadvantages of CBCT
A better understanding of patients
To decide the advantages of CBCT, let’s compare it to conventional methods. Probably the most significant advantage of cone-beam CT over fan-beam CT is that dental CBCT provides 3D information rather than 2D. Thus, this technology has become a game-changer to the dental industry, allowing dentists to come up with faster and more accurate diagnoses, treatment plans, and evaluation. For instance, with traditional fan-beam CT, only one jaw can be visualized at a time. However, CBCT can visualize both jaws at the same time.
Researchers have proven that CBCT produces a much lower radiation dose than fan-beam CT. Radiation exposure from using a standard full field of view from a CBCT machine is within 36 and 130 microsieverts. On the other hand, the average medical CBCT scan of the oral and maxillofacial area can reach 1,200 – 3,300 microsieverts. Thus, CBCT reduces the radiation level by up to 98%.
Many fields of application
CBCT systems often multiple FOV sizes for dentists to select different imaging modes for any clinical indication. For instance, the PreXion 3D Excelsior CBCT offers 5 distinct FOV sizes: 50x50mm, 100x50mm, 100x81mm, 150x81mm, and 150x130mm, allowing dentists to use this system in orthodontics, implants, oral surgery, periodontics, endodontics, TMJ, airway analysis, and ENT.
Variation of imaging mode and the possibility to select the volume size according to the diagnosis allow dental professionals to obtain excellent image resolution and minimize the risk of radiation for patients.
Faster scan time
Compared to fan-beam CT, a cone beam CT scan is faster due to the fact that CBCT produces a complete volume image in a single scan rotation, while fan-beam CT only produces a single slice image per scan.
Generally, a brand new fan-beam CT scanner can cost as much as $2.5 – $3 million, 5 times more than a brand new cone-beam CT.
Easy to use
There’s technically no learning curve when it comes to learning how to use cone-beam CT since taking a cone beam scan is almost the same as taking a panoramic x-ray. Moreover, most CBCT systems allow dentists to convert the CBCT image into other formats that are familiar to dental professionals, such as panoramic or cephalometric.
Improve patient satisfaction
A generally unthought-of benefit of using CBCT is that patients will have a much better experience when coming to your office. Usually, dentists use 2D images to visualize 3D pictures. However, patients cannot read 2D scans. But thanks to CBCT, patients can also clearly see and understand the issues they are having.
Poor contrast resolution
Probably the most significant disadvantage of CBCT is that it produces a worse contrast resolution compared to fan-beam CT, making it harder to view soft tissue. The contrast resolution of CBCT is limited by high scatter radiation during image acquisition, the divergence of the x-ray beam, and built-in flat panel detector related artifacts. If the objective of the examination is soft tissue only, using a CBCT would not be a satisfactory solution.
Artifacts are distortions in the image not related to the subject of interest. Even though streaking and motion artifacts are mostly limited while using CBCT, they are not entirely avoided. Several causes could lead to artifacts, such as minor patient movement during scanning and cone beam defects. Different CBCT manufacturers are developing their solutions to deal with artifacts, and many more studies are still needed before CBCT technology could provide a perfect image quality.
To conclude, even with some limitations, we believe that CBCT is the future of modern dentistry. When compare the advantages and disadvantages of CBCT in dentistry, CBCT is decisively superior. Dentists can spatially examine the oral conditions to the most varied medical aspects. 3D imaging also reduces the length of time patients are exposed to radiation. Additionally, the price to purchase a CBCT machine is much cheaper. And this new technology could also play a role in improving the overall patient experience for your dental office.
CBCT is quickly becoming the new standard of modern dentistry. And this trend will emerge even faster with manufacturers continually introducing advanced technology to improve the image quality and mitigate the limitations.
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