Fully digital workflow for producing implant-supported overdentures milled from PMMA on titanium bars using PEEK as the female part/sliding mechanism in three clinical visits: A case report

Purpose: To prove that a fully digital workflow, even for registration of the maxillomandibular relationship, can be employed to produce implant-supported overdentures and demonstrate that CAD/CAM techniques can be used to mill permanent implant-supported overdentures from polymethylmethacrylate discs, using polyetheretherketone as the sliding mechanism.
Materials and methods: An edentulous 64-year-old woman received six implants in the maxilla after a bone augmentation procedure and two implants in the mandible. Five months after implant placement, intraoral scans were taken of her original complete dentures, of each prosthesis individually, and of both in centric relation, and another was taken of both edentulous arches, including the scan bodies. Along with facial photographs, sufficient digital data were gathered to design and mill titanium bars, polyetheretherketone female parts and a trial implant-supported overdenture. The tooth positions and colour were discussed with the patient using Smile Design software (3Shape, Copenhagen, Denmark). In the second session, the bars and trial implant-supported overdenture were inserted and checked, and in the third session, the final implant-supported overdentures were inserted.
Results: The milled titanium bar exhibited a passive fit, as did the implant-supported overdentures. After 1 year, no prosthetic complications were noted; the measured pockets were all less than 4 mm in depth. On a visual analogue scale from 0 to 10, with 0 being the worst and 10 being the best, the patient awarded a score of 9 for her satisfaction with the implant-supported overdentures.
Conclusion: A fully digital workflow enables the production of robust wear-resistant implant-supported overdentures milled from polymethylmethacrylate, using polyetheretherketone female parts as the sliding mechanism, in just three clinical sessions.