How to Use Medit, exocad to Produce IPS e.max Crowns In-House for a Single-Visit Workflow

Transitioning from a traditional dental practice to a digital workflow presents a unique set of challenges for clinicians steeped in analog techniques. As we undertook our evolution to a completely digital clinic many years ago, we have seen how the entire market has changed and digital technologies have matured.

Modern intraoral scanners such as the MEDIT i700 are now much faster and more accurate than what we ever had access to over 15 years ago. These scanners are also much more affordable than ever before. Milling technologies, too have also improved becoming more precise, and CAD software more intuitive and user-friendly.

Most importantly, my colleagues and I worked hard to master and streamline our workflow processes, which directly impacted the profitability of our practices. Digital dentistry has completely revolutionized our practice and has resulted in much better patient outcomes. One example of this is same- day crowns, something that in my opinion is an excellent service to patients and a practice builder.

Today, our standard workflow from prep to design and mill for a single crown is all done in a single visit and can be accomplished within 2 hours or less.

Single visit dentistry provides endless advantages for the dentist and moving production in-house opens a world of opportunity and treatment possibilities. Most significantly, ROI. In our clinic, 95% of the work that was once sent to the laboratory is now completed in- house. This effectively slashed our lab bill by more than 70%. Not only that, but we no longer deal with the frustrating issues of temporary crowns.

Below, I have outlined a standard example of the sorts of cases we do every day in our practice. In this example, the patient had 2 crowns completed within a single visit. The patient had been having issues with food packing around the first molar crown due to open contacts and it was decided we would replace the crown for this tooth and crown the heavily filled second molar, too (Figure 1).

First, we start with prepping the teeth. This is standard, and with digital dentistry and modern ceramics, we can be more conservative with tooth structure, keeping margins supragingival for instance. This effectively means it is also easier to scan the preparation correctly. After I prep the teeth, I routinely use retraction cord to displace the gingiva and ensure an accurate scan of the margins and a dry field of operation to avoid contamination from blood, saliva, or crevicular fluid (Figure 2).

The preparation and tissue management part of the workflow is critical. Scanners are optical devices and if there is any gingiva or fluids such as blood on the tooth margins this will result in subpar scanning images. Incorrect use of scanners is the most common reason for a digital impression to have errors.

Following the preparation stage, I use the MEDIT i700 wireless scanner to take an intraoral scan (Figure 3). The MEDIT i700 is an extremely fast scanner and one I have personally used for many years and reviewed favorably on the Institute of Digital Dentistry website. When used correctly and with correct retraction, this scanner can achieve a full arch scan within 45 seconds easily.

The new wireless model of the i700 adds an extra layer of comfort as you do not have to worry about wires. It makes the scanning process more comfortable for the dentist.

Both HD and non-HD scans were taken using the MEDIT i700 wireless (Figure 4).

Having the option of an HD mode in the Medit scanners is quite beneficial. Although not absolutely mandatory to use, it is a simple click on the software to switch to HD mode, and as you can see in Figure 4, results in margins that are more defined and clearer. Clearer margins and an accurate scan will mean the entire CAD/CAM workflow is more efficient and easier to carry out.

Back to our workflow, once the scans are completed, this scan data is then exported to be used in our CAD software, in this case, exocad (FIGURE 5). Our dental assistants are fully trained to be proficient with using CAD software and do all of our CAD designs with clinician oversight. Medit software is also very easy to use and enables simple exporting of STL and also OBJ or PLY (color files) if required.

As you can see in Figure 5, the PLY scan file is imported into exocad software. The Medit scanner has produced a very clear digital impression for us. The next steps of the workflow are as follows – margin line placement and CAD design.

Figure 1. 

Preoperative picture of the situation the patient presented with.

Figure 2.

Completed tooth preparations for 2 IPS e.max ceramic crowns.

Figure 3.

Intraoral scan taken using the MEDIT i700 wireless.

Figure 4.

Non-HD (top) and HD (bottom) scans were taken of the same preparation to illustrate the difference when using this mode. As you can see the HD scan mode results in a higher definition scan.

Figure 5.

LY scans exported from the MEDIT i700 wireless and imported into exocad software for CAD designing.

Figure 6.

The final CAD design of 2 ceramic crowns using exocad.

Figure 7.

Nesting the CAD design in the CAM software for manufacturing.

Figure 8a.

IPS e.max CAD/CAM blocks are loaded in the milling machine and are then milled into the CAD design we have produced.

Figure 8b.

IPS e.max CAD/CAM blocks are loaded in the milling machine and are then milled into the CAD design we have produced.

Figure 9a.

IPS e.max crowns before and after postprocessing including ceramic characterization, glazing, and firing.

Figure 9b.

IPS e.max crowns before and after postprocessing including ceramic characterization, glazing, and firing.

Figure 10a.

Medit Model Builder App was used to design printable models from the intraoral scans. This was then printed using NextDent 5100.

Figure 10b.

Medit Model Builder App was used to design printable models from the intraoral scans. This was then printed using NextDent 5100.

Figure 10c.

Medit Model Builder App was used to design printable models from the intraoral scans. This was then printed using NextDent 5100.

Figure 11a.

Postoperative photograph. The final ceramic crown restorations are bonded using resin cement.

Figure 11b.

Postoperative photograph. The final ceramic crown restorations are bonded using resin cement.

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The final CAD design is completed (Figure 6) and is ready to be produced. This is a process that has a learning curve much like using an IOS device but once you learn it, it is easy and routine. This is why we provide digital dentistry courses online via our website to help teach dentists how to perform this efficiently in their practice. The design is then nested in the CAM software (Figure 7) and sent to our milling machine.

Here you can see our material of choice is IPS e.max by Ivoclar Vivadent. This is an excellent ceramic for any single unit restoration in the mouth. It is backed by over 15 years of research and high success rates over 95%.

After milling is completed, (Figures 8a and 8b) the final part of the workflow is carried out—material post processing and finishing—another aspect we train on in our online training courses.

These are the final crowns completed after polishing off the sprue and carrying out characterization and glazing (Figures 9a and 9b). This is another part of the workflow that our dental nurses are trained to do. By this point, everything is done by the team and I am free to see other patients.

One excellent aspect of the Medit Link software is the free apps included. As you see in Figure 9, the crowns are fitted on a 3D-printed model. While the crowns are milling, we can use the Medit Model Builder App to create a 3D-printable model with dies to check the fit of the crowns (Figures 10a, 10b, and 10c). This is not a required step in the workflow, and we often do single visit crowns completely modeless, but this is a good illustration of how you can use Medit Link apps in day-to-day practice.

During this entire production workflow, the retraction cord stays in place so that during the seating of the final crowns the fit at the margin is clearly visible and once cemented, excess cement is removed as the cord is removed. The most critical part to this workflow and the profitability of our practices is that while the design, milling, and postprocessing are taking place, our clinicians are busy seeing and treating other patients. The final ceramic restorations are bonded using resin cement (Figures 11a and 11b).

Perfecting a digital workflow that is efficient, predictable, and that increases profitability requires practice and understanding of all aspects of the workflow.

The first step is an intraoral scanner and the MEDIT i700 or the more affordable i600 are an excellent first step in this world of digital dentistry.

Restorations fabricated using CAD/CAM in-house has revolutionized dentistry. Digital is the future of the profession and provides endless benefits to both dentists and patients. Anyone not adopting digital techniques is falling behind. By choosing the right equipment, suitable materials and executing the treatment properly, you will have peace of mind in the long-term outcome of the result. Whether you are interested in CAD/CAM in-house or simply scanning and sending to a lab, there are many benefits for both you and the patient. The time to go digital is now.