Clinical Performance and Quality of Life of 3D-Printed Complete Dentures Under Digital vs Hybrid Workflows: A Randomized Crossover Trial

This prospective randomized crossover clinical trial evaluates and compares the clinical performance and oral health-related quality of life (OHRQoL) of complete dentures fabricated through two additive manufacturing workflows - digital and hybrid - in edentulous patients attending the Dental Clinic of Universidad de Especialidades Espíritu Santo (UEES), Samborondón, Ecuador. In the digital workflow, complete dentures are fabricated using direct intraoral scanning of edentulous ridges, CAD design, and 3D printing. In the hybrid workflow, conventional functional impressions are digitized, followed by CAD design and additive manufacturing of the definitive dentures. Each eligible participant receives two complete denture sets in a randomized crossover sequence (no washout period): Denture Set 1 is worn for 2 months, after which the participant crosses over to Denture Set 2, worn for an additional 2 months. Total active follow-up per participant is approximately 4 months. Following completion of the crossover phase, denture wear is monitored longitudinally for 12 months from the insertion of the second denture set (total study duration approximately 16 months per participant). The study addresses three specific objectives: To determine the clinical success rate of complete dentures fabricated by additive manufacturing under digital and hybrid workflows, evaluating retention, stability, denture base adaptation, occlusal balance, and need for clinical adjustments. To evaluate the impact of complete denture treatment on OHRQoL using the validated OHIP-EDENT questionnaire, assessed at the insertion of each denture set and at the 2-month control of each period (4 measurement points total). To evaluate the relationship between maximum masticatory force (T-Scan digital occlusal analysis system) and denture wear (volumetric 3D digital metrology via STL superimposition), with wear monitored over 12 months from insertion of the second denture set.

Inclusion Criteria: * Completely edentulous (bimaxillary) * Age between 50 and 90 years * Able to understand and sign informed consent * No cognitive or psychological deficits that interfere with study participation Exclusion Criteria: * Unimaxillary edentulism * Presence of Kelly syndrome * Presence of flabby tissue on alveolar ridges * No prior experience with complete dentures * Chronic motor disorders that may compromise prosthetic function