3D: Your baseline for success

March 21, 2012

THE SET-UP

THE SET-UP

“With this article, Dr. Tischler lays the groundwork for incorporating cone beam CT technology into everyday implant practice, emphasizing the importance of ‘beginning with the end in mind.’ When planning implants, the benefits of having a 3D perspective are difficult to overstate. Cone beam technology dramatically reduces radiation exposure when compared to older spiral CT technology, although patient radiation doses are still far higher than for traditional, non-computed radiographic techniques, a fact that should be taken into account when considering using CTs for dental implants."
-Dr. Brien Harvey, team lead

In the January issue of DPR, Dental Implant Clinical 360° team lead Dr. Brien Harvey did a wonderful job of answering the question, “Why implants?” Dr. Harvey’s article clearly spelled out the importance of dental implants for the general dentist, and how relevant implant dentistry will be for the general practitioner in the future.

This article starts a three-part series on how Cone Beam CT (CBCT) is clearly the foundation for treatment planning dental implants for the general practitioner as more and more GPs are getting involved with implant dentistry. This includes dentists either placing or restoring dental implants, because implant dentistry is a team approach between the surgical and restorative dentists. I will show you how current online imaging services will almost “hold your hand” to treatment plan with CBCT, eliminating the need for any software training or the need to purchase software. Because of these online imaging services, there is really no excuse not to bring CBCT into the treatment planning sequence.

This month, I will cover the basics of CBCT imaging, a little historical perspective of CT imaging, and the basics of using CT for treatment planning.

What is cone beam CT

It has only been since the late 1980s that computerized tomography has been used in dentistry and since the early 1970s that it has been used in medicine. The x-ray energy from a CT machine is directed toward an object from multiple orientations. The best way to explain how multiple orientations benefit diagnosis is to observe the diagram in Fig. 1 of the letter “A” being illuminated from two different views. If only one view were used, it would look like the letter “I.” This is what is done in the mouth with a CT, creating multiple views that are put together in a 3D manner (Fig. 2). Traditional CT machines seen in hospitals create a fan-shaped beam with a spiral radiation pattern. CBCT machines use a more targeted cone shaped beam that is specifically targeted for the head and neck regions (Fig. 3). In addition to being more targeted, CBCTs are faster and have 20% of the radiation of a traditional spiral CT; they also have a small footprint similar to a dental panograph. All of this, coupled with the cost of a CBCT machine being feasible for an implant practice, has created a dramatic increase in CBCT use in the last five years.

 

CBCT’s relevance to implant dentistry

It is an accepted concept that the success of implant dentistry lies in correct treatment planning. It also is clear to most clinicians that the prosthetic end result of dental implant support should drive the treatment planning of any implant case. Dr. Gordon Christensen has said, “the people ultimately responsible for the success of dental implants are the prosthodontist and the general dentist.” This underscores the importance of the restorative aspect of dental implant treatment.

When one looks at the literature and listens to clinicians on the podium, it is evident that using CBCT is the best available technique to treatment plan for dental implants and to tie the surgical and prosthetic aspects of treatment together. In my practice, every implant I place has a CBCT associated with it. It is rapidly becoming the standard of care and many clinicians feel it already is.

Treatment planning

Although CT use might be the standard of care, a general dentist restoring or placing dental implants may be intimidated by the software needed to analyze a CBCT, or where to find a CT site. The good news is there are many available imaging services to guide you to a CBCT site, then create an online meeting with you to review the CT data, treatment plan the case and create a presentation that you can review with your patient. This online meeting also can include the surgical and restorative dentist so a true team approach can be had.

Once a CT scan is taken the raw DICOM data must be reconstructed so 3D planning can take place. Many software programs are available to analyze CT data. Examples of imaging programs include:

  • SimPlant (Materialise Dental)

  • Implant Logic Systems (BioHorizons)

  • Nobel Guide (Nobel Biocare)

  • EasyGuide (Keystone Dental)

  • Dolphin (Dolphin Imaging)

Many dentists have purchased programs and have been trained to use them and plan their own cases. This knowledge of software and financial investment is not needed if one of the currently available imaging processing companies-such as 360 Imaging in Atlanta or nSequence in Reno-is used.

These imaging companies can create a treatment plan and radiology report using the various programs you choose. An online meeting is then set up to discuss the plan. You can begin by simply establishing an account with the company. Although these organizations do most of the work and assist in treatment planning and analyzing the CT data, the dentist must supply them with a radiographic representation of the final prosthetic tooth position on the CT (Figs. 4 and 5). This final prosthetic tooth position allows the CT to be used to plan for bone grafting and exact implant positions to support that prosthetic end result.

Michael Tischler, DDS, is a general dentist practicing in Woodstock, N.Y. He is a diplomat of both the American Board of Oral Implantology and the International Congress of Oral Implantologists. He earned his fellowship with the AGD and American Academy of Implant Dentistry. He lectures extensively and received the Feltman Hunn Medal Of Merit Award in 2007 for his contributions to the field of dentistry.