February 2013

3-D Dentistry

Author: Bonnie J. Rothwell, DMD, AAACD, FICO

It’s an exciting time in dentistry due to advances in technology. Dentists know that, in order to provide the best in patient care, information must be gathered and evaluated to make good decisions and recommendations for treatment.

The 3 Dimensional Cone Beam Computed Tomography (3DCBCT) scan is a relatively new technology available to dentists and surgeons. Previously, the only way to visualize what is below the teeth and gum tissue was with an x-ray.

X-rays are a valuable and inexpensive tool for dentists to help patients, but are not ideal for all procedures. For example, let’s consider dental implants.

Dental implants have been around for decades and are a predictable and successful treatment option to replace missing teeth. A dental implant is a small titanium product most commonly shaped similar to a tooth root. They are manufactured in different diameters and lengths in order to accommodate different areas of the mouth.

The dentist or surgeon surgically places the implant into the jaw bone where the body will naturally form mature bone around it to anchor it into place. This is called osseointegration. Once that happens, the dentist can fabricate a restoration to mimic natural tooth structure.

Implants are versatile and can be used in many different ways. They can replace a single missing tooth, several teeth, or even an entire arch. They can also be used as anchors for a complete denture to clip onto for support or used as fasteners for permanent dentures. The one thing all implants require to be successful is bone.

To evaluate the bone, the latest technology available is the 3DCBCT scan. This technology takes a series of slice images of the jaws to be treated and then specialized software stitches the images together to create a 3D image. What makes these 3D images valuable to the dental practitioner is the ability to not only see the vertical height of bone available, but also the width. 3D scans allow the dental practitioner to map out nerves and arteries, which are important to avoid when placing implants. Software tools are used to measure what size implant is most appropriate in a specific area to get the best result for the patient.

3D scans are also used to determine the quality of the bone. Bone density is naturally different in certain areas of the mouth. For example, lower jaws have higher bone density than upper jaws, and quality of bone differs in individuals due to medications, age, and other factors. Bone density is measured in Hounsfield Units (HU), and placing and moving the computer curser on the scan will tell Hounsfield Units for any given area.

Once the most appropriate treatment plan has been determined, the image can be sent to a lab for fabrication of a surgical guide. This is called computer guided surgery and offers increased precision for the actual implant placement.

Although most often utilized today for implants, the 3D scan certainly has other valuable applications in dentistry. Occasionally scans reveal dental infections or cracked tooth roots that are not visible in a traditional dental x-ray. 3D images of the temporomandibular joints are useful in diagnosing TMJ problems.

Like other dental x-rays, the 3DCBCT scan requires a low radiation dose to the patient. Radiation dose is measured in units called microsieverts. A typical full series of dental x-rays equals a dose of 150 microsieverts. A panoramic x-ray equals 75 microsieverts, and a 3DCBCT scan equals 64 microsieverts.

Let’s put that into perspective. One chest x-ray equals 1000 microsieverts, and the natural background radiation we all receive yearly just for living on earth is an average of 3100 microsieverts. Within that average, people who live in higher elevations receive approximately 1500 microsieverts more than those of us living at sea level.

The only way dental professionals can visualize critical anatomy of the mouth below the surface of the gums is through one of these radiation producing procedures. These safe, low-dose procedures are used carefully and thoughtfully by professionals, and the minimal radiation dose should not deter the patient from receiving the best care.

The 3DCBCT scanners themselves are becoming more compact and easier to use and will be increasingly available in private dental offices. However, through mobile van imaging services, the 3D scan is widely available to dental professionals who wish to provide this amazing technology to their patients.

It is an exciting time in dentistry! The new technologies available have tremendous value in not only implant procedures, but in all areas of dentistry with new applications to benefit the patient being continuously developed. Providing the best patient care is the goal and is what drives the technology industry. And that makes the patient the real winner!

Dr. Bonnie J. Rothwell is an accredited member of the American Academy of Cosmetic Dentistry and International Congress of Oral Implantologists Fellow. Her office is located at 430 William Hilton Parkway, Suite 514, Hilton Head Island. For more information, call (843) 342-6900 or visit www.hiltonheadcosmeticdentist.com.

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