Digital Immediate Dentures

The author's laboratory introduced a 3Shape TRIOS intraoral scanner (IOS) to its equipment lineup in the summer of 2018 and converted to a completely digital workflow for immediate dentures by the fall. Using the IOS with this system, there is no longer a risk of extracting mobile teeth during an analog impression, triggering tooth pain in sensitive broken teeth, or gagging the patient with impression material. Using 3Shape's denture design software allows patients to see a true mock-up of their new smile before any teeth are extracted. The following is a step-by-step guide on how to create a digital immediate denture using an intraoral scan.

First, the patient's upper and lower arches are scanned in the clinical setting, and an occlusal scan is performed. It is imperative to capture all denture landmarks with the scan, such as hamular notches and all vestibules (Figure 4). Having as much data as possible is critical so that the design software can do its job.

Prior to any treatment, it is also important to take good full-face photos of the patient showing their biggest smile (Figure 5).

Next, the scans are sent to the laboratory, where they are input into 3Shape's Dental System software. The scans are trimmed and the borders of the denture are outlined. The author prefers to keep the borders about 2 mm short of the muco-gingival junction to accommodate any tissue conditioners or liners that will be added in the weeks post-surgery.

Using the "auto tooth extraction" feature in the software, all the teeth are digitally extracted. 3Shape has a "smoothing" tool to soften any sharp edges. If needed, the designer also provides relief for mobile tissue or bony protrusions.

Next, the model is oriented for the planned path of insertion. All the undercuts are digitally blocked out so the denture is guaranteed to fit on the day of surgery without any adjustments—a very convenient time-saving feature.

At that point, a tooth design—something that is close to the size of the patient's natural teeth—is selected from one of the many available libraries. One huge asset to designing digitally is that the stock library is just a starting point. If the teeth are being printed or milled, they can be designed into any shape needed. It is possible to replicate a chipped tooth or perhaps a central diastema just like in the patient's old smile.

There is the option of bringing in a virtual articulator to open or close the patient's bite as determined by the treatment plan. It is also possible to mill in working, balancing, and protrusive occlusion.

Now the virtual denture is set into the patient photos that were taken earlier. This ensures that the planned midline, plane of occlusion, and high smile line are all correct. Once the laboratory is satisfied with the design, they take a screenshot and send it to the dentist to communicate with the patient (Figure 6).

Next, the laboratory does a virtual wax-up the denture base. The 3Shape software calculates a perfectly uniform thickness at a desired depth. It is impossible to create such an even denture base by hand in the few seconds it takes to generate one using the software.

Once the design is completed, a manufacturing file is generated for either 3D printing or CAM milling.

Following the workflow above requires only two patient appointments. The first is for the digital impressions and record-taking, while the second is for denture insertion. In Figure 7, the patient appears very pleased with the results upon delivery of his new denture.

Since November 2018, the author's laboratory has been following a 100% digital workflow for its immediate-denture patients. Being able to show the patient a mock-up of what their new smile will look like is a valuable tool. Even the most difficult cases can now be accomplished easily with just a few clicks.

Disclaimer: The statements and opinions contained in the preceding material are not of the editors, publisher, or the Editorial Board of Inside Dental Technology.

Esther Schwenning, DD, is the owner of Northern Lights Denture Clinic in Prince George, British Columbia, Canada.

Manufacturer Information:
3Shape
3shape.com
908-867-0144