This randomized controlled trial evaluates the occlusal wear of denture teeth fabricated using three digital workflows: 3D-printed denture teeth, CAD/CAM-milled double cross-linked denture teeth, and prefabricated denture teeth. Occlusal wear will be assessed over 24 months using digital superimposition techniques. The study aims to determine whether 3D-printed denture teeth demonstrate superior wear resistance compared to CAD/CAM-milled denture teeth.
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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
45
Complete removable dental prostheses fabricated using a digital workflow with CAD/CAM milling. Both the denture base and denture teeth are produced by subtractive manufacturing from pre-polymerized resin materials, including double cross-linked denture teeth, and assembled.
Complete removable dental prostheses fabricated using a digital workflow with CAD/CAM-milled denture bases combined with conventionally manufactured prefabricated denture teeth. The prefabricated teeth are selected and positioned digitally or manually and then bonded to the milled denture base.
Occlusal Wear of Denture Teeth
Occlusal wear of denture teeth will be assessed using three-dimensional digital superimposition of intraoral scans acquired at baseline and follow-up visits. Wear will be quantified as the average negative deviation (-AVG) between superimposed surfaces, expressed in micrometers (µm), representing material loss over time.
Time frame: from baseline to 24 month
Surface Deviation (Root Mean Square, RMS)
Surface deviation will be quantified using root mean square (RMS) values derived from three-dimensional superimposition of intraoral scans, providing a global measure of surface change.
Time frame: from baseline to 12, 24 and 60 months
Maximum Bite Force
Maximum bite force will be measured using a digital bite force device, expressed in Newtons (N).
Time frame: at Baseline, 12, 24, and 60 months
Chewing Efficiency
Chewing efficiency will be assessed using a standardized two-color mixing test, quantified as variance of hue (VOH).
Time frame: at baseline, 12, 24, and 60 months
Oral Health-Related Quality of Life
Patient-reported oral health-related quality of life will be assessed using the OHIP-EDENT questionnaire. The OHIP-EDENT questionnaire consists of 19 items assessing oral health-related quality of life in edentulous patients. Each item is scored on a 5-point Likert scale (0 = never to 4 = very often), with a total score ranging from 0 to 76. Higher scores indicate worse oral health-related quality of life.
Time frame: at baseline, 12, 24, 60 months
Denture Satisfaction
Patient satisfaction with dentures will be assessed using a validated questionnaire. Denture satisfaction will be assessed using a Visual Analog Scale (VAS) ranging from 0 to 10, where 0 indicates no satisfaction and 10 indicates maximum satisfaction. Higher scores reflect greater patient satisfaction with the prosthesis.
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Description Complete removable dental prostheses fabricated using a fully digital workflow in which both the denture base and denture teeth are produced by 3D printing using light-curing resin materials. The prostheses are designed digitally and manufactured additively.
Time frame: at baseline, 12, 24, and 60 months
Denture Retention
Retention of the maxillary denture bases will be assessed by measuring the force required to dislodge the prosthetic base from the denture-bearing tissues. A digital dynamometer will be attached to a standardized central hook incorporated into the test base. The base will be seated intraorally, and a controlled vertical traction force will be applied until dislodgement occurs. The maximum force required to dislodge the base will be recorded in Newtons (N). Higher values indicate greater denture base retention.
Time frame: at baseline
Color Stability
Color changes of denture teeth will be assessed using colorimetric measurements and expressed as ΔE values.
Time frame: at baseline, 12, 24, and 60 months
Total prosthesis fabrication cost
Costs related to prosthesis fabrication will be recorded for each study group. This will include initial laboratory fabrication costs in swiss francs CHF per participant.
Time frame: at baseline,
Number of Prosthetic Maintenance Visits
The number of additional prosthesis-related maintenance visits required after prosthesis delivery will be recorded for each participant. Maintenance visits may include visits for adjustment, repair, relining, or management of prosthetic complications. it will be measured as the number of prosthetic maintenance visits per participant (NPMV) and cost associated to each visit in Swiss francs (CHF) per participant.
Time frame: from baseline to 12, 24, and 60 months
Incidence of Prosthetic Complications
Prosthetic complications will be recorded as the number and percentage of participants experiencing at least one clinically relevant complication during follow-up. Complications may include denture base fracture, tooth detachment, prosthesis damage, loss of retention requiring intervention, relining, repair, or prosthesis remake/replacement. Each event will be documented by type and timing.
Time frame: From baseline to 12 months, 24 months, and 60 months