By Dr. Daniel Butterman, International Congress of Oral Implantologists Fellow and Resident Faculty Member at CDOCS.com.
3D imaging scanning offers numerous benefits – from greater convenience for patients to increased therapy acceptance. However, one of the most important aspect of 3D imaging scans is the ability to predictably perform guided implant surgery. If you can understand where your final restoration is going to be before you ever touch the patient, that’s a major improvement.
Improving implant surgery
Dentists sometimes focus on the implant first and putting the implant in the right position but when it comes to putting the tooth in, then they run into trouble. If the implant isn’t in a position where it lines up with the crown, the lab might not be able to create a properly angled abutment, or the screw access position will be in the wrong place. To avoid these issues, you need to evaluate the space for the implant, but just as importantly, the space for the restoration. It's difficult to judge by eye if a properly contoured crown will fit in the space. That's why it is important to design an actual crown into the future implant space.
Merging together three-dimensional imaging view from Axeos and a scan from a CEREC Primescan will show you exactly how much room you actually need. Without 3D imaging, it’s possible to lose perception when free handing an implant, and end up with disastrous results. This is either due to not having a plan of where the implant should go or not having an easy way to execute on that plan during surgery. It is important to have both of those pieces to avoid those situations.
In a typical analog/2D workflow when someone has missing teeth, the process would typically involve:
- Taking an impression and sending it to the lab for a diagnostic wax-up
- Taking an x-ray to see where the teeth are in relation to the bone
- Getting a barium sulfate scanning dye
- Requesting a surgical guide from the lab
By the time the patient says they are interested in getting implants, they’ve already had to wait many weeks and spend several hundred dollars just to do the planning. Especially in the age of digital and CAD/CAM dentistry, patients are expecting things to happen very quickly, and aren’t okay with things taking this long.
Guided surgery workflow
It’s much more efficient to use 3D imaging, to save time and to avoid any surprises. In our practice, we use the CEREC Guide 3, which is the latest version of guided software from Dentsply Sirona. It’s compatible with our Axeos CBCT and Dentsply Sirona implants.
If a patient comes in with a missing molar, the first step is to talk with them about how we can potentially restore it. The workflow includes:
- Taking an Axeos scan to understand the biology. The Axeos 3D Imaging System has automatic positioning, so patients no longer need to hold still while scans are taking place. This helps eliminate poor imagery due to unintended movement.
- Having my assistant take an optical scan with the Primescan system. This captures the area where the patient is edentulous.
- Automatically creating a crown proposal. At this point we can show the patient what the crown is going to look like, and explain different options.
- Importing the crown design into the patient’s x-ray. This will show us if they have enough bone for the implant. If we need to perform grafting, we can show the patient this in the 3D image so they can better understand why it’s needed.
Once the implant is designed, we move to the manufacturing phase to see what the block looks like, and then mill it out. This takes roughly 35 minutes, and can be done live in front of the patient. From there, we manufacture the CEREC Guide 3 and place the implant.
The advantage of this system is that you can perform fully guided osteotomy and fully guided implant placement without using keys. Most guided surgery systems require a long key to shrink the diameter of the guide hole for each consecutive drill, and that can be cumbersome. The Astra EV Guided Kit we use has a miniature sleeve on the drill that makes this process much easier.
There’s no need to check films during surgery because the whole process is done guided. Since everything is planned up front, the implant can only end up in one place. With this workflow, the entire surgery, from anesthetic until the patient leaves the office, takes roughly 20 minutes.
Historically, many dentists have found that patients who they approached about teeth straightening were opposed to getting braces. Today, we can show them in 3D what their final crown will look like, and demonstrate how moving teeth out of the way will give a proper-looking tooth.
For example, a patient with a missing primary canine was scheduled with a surgeon to have an implant placed at number 11. His wife convinced him to come in to our practice and get a second opinion. To create a crown proposal, my assistant did an optical scan and drew a margin around where tooth number 11 was supposed to be. She put the lower jaw into place on the screen, and it was immediately obvious that the patient’s occlusion was in the way and there wasn’t enough room for the implant.
In that case, we were able to have a discussion with the patient and show him how he would be much better served having orthodontic treatment first to move his teeth into the right space. The patient agreed, and the result was better for it.
Nowadays, with the current technology available, there’s no need for mystery or surprises during implant surgery. 3D imaging software - coupled with the right training to make maximum use of the software – enables dentists to have a digital process from prosthetic planning all the way through execution of it surgically. This benefits patients and practitioners alike. For patients, they are more part of the process, and they can get in and out of the dentist office in fewer visits. Perhaps most importantly, 3D imaging technology takes the pressure off practitioners, who now have the assurance up front that they’re placing implants precisely.
The workflow for planning for an implant is fairly straightforward with Axeos CBCT and
- Choose the CEREC guide planning, implant positioning, and prosthetic plan.
- Select the tooth and move into the acquisition phase.
- Scan the edentulous space. This is what will be used to manufacture the surgical guide.
- The software then designs a crown proposal, taking into account the adjacent teeth, the opposing teeth, as well as any occlusal spots so you know where the restoration needs to go.
- Edit it as needed.
- Show the crown proposal to the patient to gain their buy-in.
- Export the file into your CBCT software to create a color SIXE file.
- Open the implant module and scan through it.
- For mandibular posterior implants, map the nerve so you know where the mandibular canal is.
- The software will alert you if you bring the implant too close to the nerve.
- Import your optical scan.
- Identify the common points so that the optical scan can be merged with the x-ray. Then you can see exactly where the gingiva is, based on the optical scan and where the bone is, based on the x-ray.
- Choose from your catalog of implants and drop it in.
- Use the rotational tools to position the implant so that it lines up both in bone and properly underneath the crown.
Now that the planning stage is finished:
- Export the file back into the CEREC software.
- Set the sleeve and define the seating area where you want your surgical guide to sit.
- Create inspection guides as needed to verify that they seat properly.