Digital Denture Excellence

Simplified workflow for both laboratory and clinician

By Bill Barton, MBA (MM), BS, CDT, TE

The following case demonstrates the workflow options of impressions and bite (Centric Tray, Ivoclar Vivadent; ivoclarvivadent.com) into the 3Shape denture design module using Ivoclar Vivadent's Digital Denture Professional (DDP). First, the clinician must take one set of good impressions and a Centric Tray bite to acquire the patient's vertical dimension, and use them to fabricate the try-in dentures. These impressions and bite are considered preliminaries or finals based on the results of the try-in appointment. Second, the try-in is not the traditional wax try-in but monolithic and rigid, either milled or printed. If the fit is not ideal during the try-in appointment, the clinician must take a wash-impression to better capture the tissue surface, which is rescanned to the original design prior to final fabrication. The same is true if the vertical dimension or esthetics are not optimal. Vertical/bite modifications are made by taking a new bite registration with the try-in and rescanning to the design. Changes to the esthetics of the case are communicated back to the laboratory by writing the changes on the try-in. The third hurdle to overcome is within the design software itself. The 3Shape denture module looks for either a triple-tray impression or models and bite in the scan suite (versions 17.2 to 18.2) (3Shape; 3shape.com); impressions and the Centric Tray bite are only available options in the DDP 3D Bite Plate scan suite. The current workaround is to scan the impressions and Centric Tray as a 3D Bite Plate design and import the scans into the denture design order. This workflow capitalizes on the combination of the Centric Tray and UTS CAD device (Ivoclar Vivadent) for establishing the occlusal plane as well as the bi-papillary plane, thereby reducing most try-in discrepancies.

In the first appointment with the patient, the impressions, Centric Tray bite, UTS CAD measurements, papillameter and/or denture gauge measurements (optional), and tooth mold and shade selections were completed (Figure 1 through Figure 4). The laboratory then needed to perform several steps on their end. First, the author scanned the impressions and Centric Tray in 3D Bite scan suite, saved, and closed the program (Figure 5 and Figure 6). Then, the full denture order was created, and the scans were imported into the order (Figure 7). At that point, the denture try-in was designed as prescribed (Figure 8 and Figure 9), and the CAM output was imported into the PrograMill CAM4 (Ivoclar Vivadent). The project was edited as necessary (eg, insertion access, etc), but minimally, as the material and milling template/strategy had already been determined in the CAD design. Lastly, the try-in was nested and milled from the ProArt CAD Try-in disc material (Ivoclar Vivadent) (Figure 10).

At the patient's second appointment, the try-in was placed to assess fit, function, midline, lip-line, etc (Figure 11). Any required modifications—ie, wash-impression, new bite registration, new mid-line, etc—were made at that time (Figure 12). Note: The Centric Tray does not represent or determine centric relation, but does provide a very good starting point for the patient's vertical dimension of occlusion. In this case, the bite required a slight occlusal adjustment.

Based on the outcome of this try-in appointment, the laboratory needed to follow up with a number of steps. First, the laboratory changed the material to IvoBase Cad and Vivodent CAD DCL for the PrograMill platforms (PM7 mill) (Figure 13) and ensured that the manufacturing process was set to Milled Teeth with the CAM5 output. Next, Copy and Reuse CAD Design was selected, then Scan chosen to rescan the modifications to the try-in (Figure 14). After this, the scan was aligned to the original try-in, then brought to Design to make prescribed adjustments, ie, occlusal plane, bi-papillary, etc, and complete the final dentures (Figure 15). At that point, the CAM output was once again imported into the PrograMill CAM software, then nested (Figure 16). The Oversized mill settings were used to nest and mill teeth and denture bases from the Vivodent CAD DCL and IvoBase CAD disc materials (Figure 17).

At only the third appointment, the dentures were delivered, resulting in another satisfied digital denture patient (Figure 18 and Figure 19).

When the author was a young technician, he could have never imagined how things would change in the future. In conjunction with 3Shape's Denture module, Ivoclar's Digital Denture Professional (DDP) Add-on provides unsurpassed workflow options to today's laboratories.

Many technicians assessing a digital workflow are concerned about costs. Considering the costs associated with a scanner, design software, a mill, and/or a printer, the price tag can seem out of reach for some. Each owner or manager must take a hard look at what will provide his or her laboratory with the digital advantage while keeping a profitable return on investment (ROI). This advantage may come from the all-in approach or perhaps a smaller investment, such as acquiring a scanner and the design software while outsourcing some or all of the design and/or production processes.

Ivoclar Vivadent's DDP gives laboratories the flexibility to incorporate the digital process that suits their strategic business plan. The desired strategy must offer the laboratory an acceptable ROI and offer options that meet their dentists' needs without asking them to change their clinical processes or learn elaborate new techniques. The idea is to keep it simple: impressions or models and a bite. The only way to achieve consistently high-quality, fitting dentures is with good impressions and a proper bite relationship.

Acknowledgement: The author would like to thank Frank Lauciello, DDS, Director of Removable Education at Ivoclar Vivadent, Inc.