Since its invention and the ability to look at the human body in a 3-D perspective, advancements have made it practical for clinicians to either own a CBCT or have access to a mobile CT unit. Scan times and radiation levels have decreased, making CTs safer and more practical to have in a clinical setting.
This month’s Implants Today topic focus is on cone beam computed tomography (CBCT) planning for implant dentistry. In 2012, Implants Today Advisory Board member Dr. Scott Ganz and I authored a 3-part article series in Dentistry Today entitled, “The CT-Based Team Approach to Care” (Part 1, Part 2, Part 3). This series discussed how treatment planning, surgery, and prosthetics relate to a CBCT scan and the team approach. I bring up that article series to remind us how important CBCT has become for every aspect of implant dentistry including treatment planning, surgery, and prosthetics. In the time since the its inventors, Hounsfield and Cormack, received the Nobel Prize for Medicine in 1979, CT technology has greatly impacted implant dentistry and is a large part of the current success with dental implants.
Since its invention and the ability to look at the human body in a 3-D perspective, advancements have made it practical for clinicians to either own a CBCT or have access to a mobile CT unit. With multiple CBCT companies in competition with one another, the scan times and radiation levels have decreased substantially and the size of the CT units have all decreased during the past 37 year as well, making CTs safer and more practical to have in a clinical setting.
TO BUY OR NOT TO BUY?`
I am often asked for advice on which CBCT machine to purchase, and if a practitioner can support the costs involved and realize a decent return on investment (ROI) from the CBCT equipment. Choosing the right CBCT machine for a dental practice is a decision that mandates investigation of the style and size of the unit, ease of operating features, cost, associated software, and how fast the unit could be serviced, if needed. These are all somewhat subjective considerations, dependent on each clinician’s situation. Only after through research can that decision be made; doing this research will educate the clinician on many levels to ensure that the right choice has been made, making it easier to introduce this new technology into the practice and to patients.
So, how does a clinician know if a practice can financially support a CBCT machine, or if it would make more sense to utilize a mobile CT unit that comes directly to the dental facility after making an appointment? The answer to that is based upon various considerations, with the most important being: “Where does the clinician want to be in a year or so, from a vision standpoint?” If one has a vision to do more implants, and the clinician has the skills to perform implant dental treatment, then an on-premises CBCT machine has a high potential to make a positive ROI. One should know that the ROI for a CBCT machine is not calculated as simply as how many CT scans are being taken and how much a clinician is being paid for the scan itself. The immediate information to which a clinician can have access, and discuss with a patient by having a CBCT machine right on premises, offers many benefits that are sometimes overlooked when looking at ROI. As an example of the efficiency brought to the table by having this technology readily available, a CBCT can be taken on a new patient and the clinician can then review the information and offer a treatment plan at the first visit. It is not only impressive to the patient but also offers a large convenience factor. In my practice experience, having an on-site CBCT has led to an increased treatment acceptance rate.
There are other clinical advantages that can make having an on-site CBCT a good choice. In my practice, we often take a post-extraction CBCT before immediate implant placement, either in a full arch or in a quadrant. Having a CBCT machine on the premises allows for immediate placement of implants with CBCT guidance. Although a mobile CBCT unit could provide the same result, it would be logistically more cumbersome. Another clinical advantage of an on-site CBCT are follow-up CBCT scans on bone grafts, pathology, and complications. Having an on-site CBCT for these purposes offer many advantages to a practice.
CBCT Scans Routinely in Implant Dentistry: The Standard of Care?
In my opinion, a CBCT scan should become the standard of care for implant placement. There is not yet a full consensus among dental implant experts that use of a CBCT in implant dentistry is the standard of care. While many dental implants can be placed successfully without a CBCT scan, if there is a complication, a clinician could be asked why a CT was not taken. There is really not a defendable answer, since mobile CBCT units and other CBCT machines are now so readily available. I simply do not believe a clinician should take the chance of delivering implant dentistry without the detailed information that CBCT technology provides.
Furthermore, I also believe that there is no area of the mouth of which a clinician can justify that a CBCT should not be taken. The inferior alveolar nerve in the posterior mandible can be identified in CBCT software programs so that it can be properly avoided. A CBCT scan in the posterior mandible can also identify the angulations of the lingual wall so as to avoid perforations. The information offered in the CBCT scan can be utilized with either a guided or nonguided approach. In the posterior region of the maxilla, a CBCT scan can offer information to the location of the sinus wall, allowing the clinician to utilize osteotomes or lateral wall grafting, as indicated. In the process of making the most educated decisions possible, a panoramic radiograph does not offer the detailed information that CBCT technology provides. The anterior mandible presents many challenges that a CBCT scan can help navigate. A CBCT scan in the anterior mandible can not only help avoid lingual cortical plate perforations, but can also help prevent many other prosthetic and surgical complications. The anterior maxilla offers many challenges for the clinician, as the final prosthetic result is visible in most cases, depending on the patient’s smile-line. Bottom line? Having a CBCT scan for evaluation in the anterior maxilla can help avoid a multitude of prosthetic and surgical complications.
Professional Evaluation of the CBCT Scan
Once a CBCT scan is taken, I recommend that an evaluation of the CT scan is done with a formal report by a board-certified radiologist. It once again negates any risk of missing pathology on a scan that one, as a clinician, is (or may be) responsible to see and relay to a patient. After utilizing radiology reports as a standard for many years, I have seen many pathological situations that I would not have found on my own. These include carotid artery blockages, tumors and cysts in the cranial area, airway issues, vertebral pathology, and more. The minimal fee for the radiology report is justified in my opinion, and it is a real plus simply for peace of mind. Most dentists are not educated enough in the arena of radiological findings and interpretation to match the training and knowledge of a radiologist.
DICOM Data: CBCT Software Programs
The Digital Imaging and Communications in Medicine, or DICOM, data from a CBCT scan must be read by a CBCT software program for planning and diagnosis. Most CBCT companies have a resident software program that is part of the CBCT purchase. There are also independent company software CBCT programs that are more robust than standard software programs and come with a CBCT purchase. These “after-market” programs that read the DICOM data can offer advantages such as accurate anatomic implant placement on the program, advanced nerve mapping, improved detail 3-D mapping of prosthetic structures, portals to order surgical guides, and more. It is an advantage for a clinician to be able to utilize the CBCT software program in planning an implant case. Adept utilization of a CBCT program allows the clinician to offer a patient valuable and immediate information.
It is clear that CBCT scans are the backbone to successful dental implant treatment. I find this topic extremely important in the realm of implant treatment. CBCT scans offer an advantage to success for implant placement in every area of the mouth, for single implant placement or full arch and for bone grafts. As a clinician involved with implant dentistry, I recommend you embrace this technology that is safe, accurate, and offers a substantial tool toward successful implant treatment for patients.
This month, we have selected exceptional implant articles for our readers. Dr. Ara Nazarian presents a full-arch cement-retained zirconia implant case in which CBCT information played a vital role. Ara utilized information/data from CBCT scans to create 3-D models and surgical guides. The process that he showcases demonstrates the ultimate in the utilization of the CBCT process using digital technology to ensure a predictable prosthetic success.
Implants Today Advisory Board member, Dr. Michael Scherer, also presents an excellent article that shows how a CBCT scan can be used to plan for an overdenture case. This further shows how CBCT scans translate to success when executing both removable and fixed implant prosthetic options.
I have also authored an article on CBCT scans related to full-arch implant restorations. This article incorporates many of the principles mentioned in this section and it is my hope that it helps stress the points introduced above in this month’s introduction to Implants Today.
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