PRINTOW: Occlusal Wear of Denture Teeth in Digitally Fabricated Complete Dentures

This is a single-center, prospective, randomized, controlled, double-blind clinical investigation comparing three digitally fabricated complete removable dental prosthesis workflows in edentulous patients. The study will be conducted at the University Clinics of Dental Medicine, University of Geneva.

The study includes adult patients who are completely edentulous in the maxillary and mandibular arches and require new complete removable dental prostheses. Participants may be rehabilitated with either a conventional mandibular complete denture or a mandibular implant overdenture supported by clinically stable implants. This inclusion strategy is intended to improve recruitment feasibility and reflect real-world clinical practice. Mandibular prosthetic status at baseline will be used as a stratification factor during randomization and will be accounted for in the statistical analysis.

A total of 48 participants\*\* will be randomized in a 1:1:1 allocation ratio to one of three treatment groups: fully 3D-printed complete dentures with printed denture base and printed denture teeth; CAD/CAM-milled complete dentures with milled double cross-linked denture teeth; or CAD/CAM-milled complete dentures with prefabricated denture teeth, serving as a clinical benchmark group.

The primary objective is to compare occlusal wear performance of denture teeth between the fabrication workflows. The primary confirmatory comparison will be conducted between the fully 3D-printed workflow and the CAD/CAM-milled double cross-linked workflow. Occlusal wear will be assessed by three-dimensional digital superimposition of intraoral scans acquired at baseline and follow-up visits. The primary endpoint is the average negative deviation of occlusal surfaces at 24 months, representing material loss over time.

\> Secondary outcomes include root mean square surface deviation, patient-reported outcomes assessed with the Oral Health Impact Profile for Edentulous Patients and the Denture Satisfaction Index, chewing efficiency, bite force, prosthetic retention, color stability, prosthesis-related costs, maintenance interventions, and prosthetic complications. These outcomes will be assessed according to the study schedule at baseline and during follow-up visits at 12, 24, and 60 months.

Participants and outcome assessors will be blinded to denture fabrication workflow and denture tooth material allocation. Prostheses will be labeled using anonymized codes, and digital files used for wear analysis will be anonymized using participant study ID and time point. Treating clinicians and laboratory personnel will not be blinded due to the nature of the intervention, but they will not be involved in blinded outcome assessment.

All prostheses will be fabricated according to standardized clinical and laboratory procedures using CE-marked medical devices and materials according to the manufacturers' instructions for use. The prosthetic treatment phase will include clinical evaluation, impressions, intermaxillary records, prototype try-in, and delivery of the final prostheses. Follow-up assessments will be performed after prosthesis delivery to evaluate clinical, functional, patient-reported, material-related, and maintenance outcomes.

• Surface Deviation (Root Mean Square, RMS) [Time frame: from baseline to 12, 24 and 60 months]
• Maximum Bite Force [Time frame: at Baseline, 12, 24, and 60 months]
• Chewing Efficiency [Time frame: at baseline, 12, 24, and 60 months]
• Oral Health-Related Quality of Life [Time frame: at baseline, 12, 24, 60 months]
• Denture Satisfaction [Time frame: at baseline, 12, 24, and 60 months]
• Denture Retention [Time frame: at baseline]
• Color Stability [Time frame: at baseline, 12, 24, and 60 months]
• Total prosthesis fabrication cost [Time frame: at baseline,]
• Number of Prosthetic Maintenance Visits [Time frame: from baseline to 12, 24, and 60 months]
• Incidence of Prosthetic Complications [Time frame: From baseline to 12 months, 24 months, and 60 months]