Using 3D Digital Denture Technology to Treat Edentulism

By Sean Thorp, CDT, and Jim Miller, DDS

The substantial growth in the population of edentulous patients has been well-documented, and the authors have observed it first hand over several decades. Additionally, the number of dental laboratory technicians has been declining-especially in the removable area. Finding experienced denture technicians has been a challenge throughout the United States. While the primary author was interviewing and trying out some potential laboratory technicians, he was approached by a clinical representative from Kulzer regarding digital dentures and the Pala Digital Dentures brand. This was very interesting because the laboratory was very involved in digital technology in its fixed department. The primary author pursued this digital denture technology, hoping it would help the laboratory improve its efficiency and proficiency in the fabrication of removable dentures.

The next step was getting the clinician onboard to utilize this technology. The whole team must work together to make this all come together. This was easier than anticipated, however. The primary author contacted a few clients, some younger dentists and even some that had been in dentistry for quite some time, and they were all willing to try it out. They now have now utilized Pala Digital Dentures for approximately 2 years, with very strong success. It is well known that technology advances, and in this area, it is advancing very rapidly, with both milled dentures and 3D printed dentures. The primary author explored both options and followed the direction of the 3D printed dentures, purchasing the first Kulzer cara Print 4.0 3D printer in the United States, and has yet to be disappointed.

Case Presentation

A 62-year-old male presented with edentulous upper and lower arches. He had been edentulous for 3 years, due to broken down dentition and decay. He had a small torus in the middle of the maxilla (Figure 1). He was advised to have it removed but decided against it. The clinician and technician decided to proceed with case.

Clinical steps

The first step, of course, was to take impressions. Two options exist for this (Figure 2 and Figure 3).

The first option is Kulzer's Pala Digital Denture impression system, which can help obtain the vertical dimension of occlusion (VDO) as well as a Gothic arch tracer to obtain centric occlusion. The first step is to choose the size of the tray (small, medium, large, or extra-large). Next, use a heavy-body impression material to border mould the tray. Place it in the mouth and manipulate the cheeks and lips. Remove the impression tray, load it with medium-body material, and place it in the mouth for the impression, pressing firmly on the designated area on the impression tray. Repeat for the lower impression.

Next, cut the distal of the impression on the lower as designed on the tray. Unsnap the distal extensions. Place the VDO pin in the tray, and open and close it to obtain the correct VDO. Utilize the Gothic arch tracer to obtain centric relation. Use bite registration material to lute both arches together. Remove from the patient and send to the laboratory. Pictures of patient are also very helpful.

The second option is to take initial impressions and make custom impression trays. Take the final upper and lower impressions, and send them to the laboratory to make bite blocks. Place the bite blocks and trim the wax to obtain the proper VDO. Using a Fox plane also helps obtain the proper occlusal plane. Also mark the patient's midline, smile line, and canine line on the bite block. Send to the laboratory to mount on an articulator. Pick the shade and mould of teeth. The authors use Kulzer Mondial i teeth.

Denture Fabrication

Having obtained all the information required, the laboratory could scan the models with a 3Shape scanner to produce an STL file for Kulzer to design the dentures. Once the information was received by Kulzer's design team, they imported it into their software and designed the dentures. The design team then emailed the laboratory a PDF file that could be manipulated to review the design and communicate any desired changes. Once the laboratory approved the design, the final version was sent so a prototype denture could be printed with the cara Print 4.0 and sent to the clinician for try-in (Figure 4). The clinician checked for fit, bite, VDO, and esthetics. The VDO on the patient looked great (Figure 5). The bite was spot-on and the fit was great. The patient could hardly remove the dentures from his mouth. There were no adjustments necessary in this case, but if the bite had needed to be adjusted of the VDO needed to be opened or closed, the laboratory would have taken a bite rescan of the prototype and sent it back to the designers to import the new scan with adjustments and adjust as needed.

Final Fabrication

Because no adjustments were necessary, the laboratory asked the designers to send the split file, which included the denture teeth. Anteriors were splinted and the posteriors were splinted, so three separate segments were on each arch, in addition to the denture bases. The primary author next printed the denture bases with the cara Print 4.0, using pink denture base material (Figure 6). The material was then changed to print the teeth (Figure 7). Once the teeth and bases were printed (Figure 8 and Figure 9), the teeth were luted to the bases using the same resin that the base is printed from and cured once done. Once cured with the HiLite power curing unit, the denture could be custom-stained using Creactive composite stain kit (Figure 10).

Delivery Day

On the day of delivery, the clinician placed the upper denture and checked for fit and esthetics. The lower was placed, and fit and bite were checked. Everything was beautiful, and the patient was ecstatic (Figure 11).

Conclusion

The authors were able to use digital technology as a helpful tool in the dental laboratory to compensate for the difficulty of finding experienced technicians. Additionally, the clinician has fewer appointments for the patient and provides better materials. Technology continues to advance, and in the near future the clinician will be able to use intraoral scanners to take the impressions digitally for removable appliances.

About the Authors

Sean Thorp, CDT

A Quality Dental Lab • Post Falls, Idaho

Jim Miller, DDS

Hayden, Idaho