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

Clinical Success, Oral Health-Related Quality of Life, and Relationship Between Maximum Masticatory Force and Denture Wear in Complete Dentures Fabricated by Additive Manufacturing Under Digital and Hybrid Workflows: A Prospective Randomized Crossover Clinical 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.

Study Overview

• Status: Recruiting
• Conditions: Complete Edentulism
• Intervention / Treatment: Device: Digital Workflow Complete Denture; Device: Hybrid Workflow Complete Denture

Detailed Description

BACKGROUND Edentulism remains a significant public health concern, particularly among older adults, due to its impact on masticatory function, facial aesthetics, phonation, nutrition, and psychosocial well-being. Complete denture rehabilitation is the standard of care for edentulous patients; however, conventional fabrication techniques are associated with dimensional inaccuracies, multi-step laboratory procedures, and interoperator variability. The introduction of CAD-CAM systems and additive manufacturing (3D printing) offers potential advantages including improved precision, streamlined clinical workflows, and enhanced reproducibility. Despite growing clinical interest, robust evidence comparing digital and hybrid workflows - including patient-reported outcomes, clinical success, and objective functional measures such as masticatory force and denture wear - remains limited.

STUDY DESIGN Prospective, controlled, randomized, double-blind (participant and outcomes assessor), crossover clinical trial. No washout period between denture sets. Each participant receives two complete denture sets - one fabricated by digital workflow and one by hybrid workflow - in a randomized sequence. Total crossover phase: approximately 4 months per participant. Denture wear follow-up: 12 months from insertion of the second denture set.

PARTICIPANTS Completely edentulous adults aged 50-80 years requiring bimaxillary complete denture rehabilitation, attended at the UEES Dental Clinic. Recruitment is ongoing; first clinical appointments begin June 2026. Target sample: 28 participants (20 required for 83.7% power based on effect size d=1.25 from Peroz et al. 2024; 8 additional for anticipated dropout). Sample size calculated using G*Power 3.1, Wilcoxon-Mann-Whitney test, α=0.05, power=0.80.

INTERVENTIONS

Intervention A - Digital Workflow (3 clinical appointments):

Appointment 1: Intraoral scanning of edentulous ridges (TRIOS 5, 3Shape); digital recording of vertical dimension, intermaxillary relationship, and occlusal plane orientation.

Appointment 2: Clinical try-in of 3D-printed prototype (Asiga TRY resin, Asiga MAX 2 printer).

Appointment 3: Delivery of definitive 3D-printed complete denture (DentaBASE resin; VarseoSmile TriniQ teeth, BEGO).

Intervention B - Hybrid Workflow (5 clinical appointments):

Appointment 1: Preliminary impression and custom tray fabrication. Appointment 2: Functional impression with elastomeric materials. Appointment 3: Interocclusal registration (vertical dimension, centric relation, occlusal plane) with wax rims.

Appointment 4: Conventional wax try-in. Appointment 5: Delivery of definitive complete denture (conventionally impressed, digitally designed, additively manufactured base; DentaBASE resin; VarseoSmile TriniQ teeth, BEGO).

STUDY TIMELINE PER PARTICIPANT

Month 0: Insertion of Denture Set 1 (randomized: digital or hybrid) + baseline OHIP-EDENT + baseline T-Scan + baseline denture scan Month 2: 2-month control of Denture Set 1 + OHIP-EDENT + T-Scan + denture wear scan → Crossover: insertion of Denture Set 2 Month 4: 2-month control of Denture Set 2 + OHIP-EDENT (final crossover endpoint) + T-Scan + denture wear scan Months 4-16: Denture wear follow-up of Denture Set 2 at scheduled intervals (12-month longitudinal wear monitoring from insertion of Set 2)

RANDOMIZATION AND BLINDING Randomization sequences (A→B or B→A) generated by an external investigator using random.org. Concealed in sequentially numbered opaque sealed envelopes opened only after participant enrollment. The clinical operator cannot be blinded to the workflow; however, the participant and the outcomes assessor remain blinded throughout the study.

PRIMARY OUTCOME Oral health-related quality of life assessed by OHIP-EDENT total score at 4 time points across the crossover period.

SECONDARY OUTCOMES

Clinical success rate (composite: retention, stability, base adaptation, occlusal balance, need for adjustments) Maximum masticatory force (T-Scan; relative force and distribution) Denture wear - volumetric surface loss (mm³) via 3D STL superimposition over 12 months from Set 2 insertion Correlation between maximum masticatory force and denture wear

STATISTICAL ANALYSIS Normality assessed by Shapiro-Wilk test. Crossover comparisons (Obj. 1 and 2): paired t-test or Wilcoxon signed-rank test; categorical variables by McNemar's test; period and carryover effects evaluated. Longitudinal wear analysis (Obj. 8): repeated-measures ANOVA or Friedman test across time points; force-wear correlation by Pearson or Spearman coefficient. Significance: α=0.05. Missing data handled by intention-to-treat analysis where possible.

ETHICS Protocol approved by the Human Research Ethics Committee of Universidad de Especialidades Espíritu Santo (CEISH-UEES), Samborondón, Ecuador (March 2026). Conducted in accordance with the Declaration of Helsinki. Written informed consent obtained from all participants prior to enrollment.

• Study Type: Interventional
• Enrollment (Estimated): 20
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Pablo Benitez, phd; Phone Number: +593996516891; Email: pbenitez@uees.edu.ec

Study Locations

• Ecuador
  • Guayas
    • Samborondón, Guayas, Ecuador
      • Recruiting
      • Clínica Odontológica - Universidad de Especialidades Espíritu Santo (UEES)
      • Contact: Patricia Ayala Director; Phone Number: +593 98 851 1041; Email: payalaa@uees.edu.ec
      • Principal Investigator: Pablo Benitez, PhD
      • Sub-Investigator: Andres Ullauri, Dentist

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

Completely edentulous (bimaxillary) Age between 50 and 80 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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: digital workflow; Participants receive complete dentures fabricated by digital workflow first (intraoral scanning + CAD + 3D printing, 3 appointments), worn for 2 months, then cross over to hybrid workflow dentures for an additional 2 months.	Device: Digital Workflow Complete Denture; Complete dentures fabricated using direct intraoral scanning of edentulous ridges (TRIOS 5, 3Shape), CAD design (3Shape Dental System), 3D-printed try-in prototype (Asiga TRY resin, Asiga MAX 2 printer), and definitive 3D-printed denture (DentaBASE resin; VarseoSmile TriniQ teeth, BEGO). Completed in 3 clinical appointments.
Active Comparator: Hybrid Workflow; Participants receive complete dentures fabricated by hybrid workflow first (conventional impressions + digitization + CAD + 3D printing, 5 appointments), worn for 2 months, then cross over to digital workflow dentures for an additional 2 months.	Device: Hybrid Workflow Complete Denture; Complete dentures fabricated using conventional preliminary and functional impressions (elastomeric materials), interocclusal registration with wax rims, conventional wax try-in, digitization of the impression/master model via laboratory scanner, CAD design (3Shape Dental System), and additive manufacturing of the definitive denture base (DentaBASE resin; VarseoSmile TriniQ teeth, BEGO). Completed in 5 clinical appointments.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Oral Health-Related Quality of Life - OHIP-EDENT Total Score	19-item validated questionnaire (Allen & Locker, 2002). Each item scored 0 (never) to 4 (very often). Higher scores indicate worse OHRQoL. Assessed at 4 time points across the full crossover period to capture quality of life evolution under each workflow.	t insertion of Denture Set 1 (Month 0); at 2-month control of Set 1 / insertion of Set 2 (Month 2); at insertion of Set 2 (Month 2); at 2-month control of Set 2 (Month 4)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Clinical Success Rate	Composite endpoint assessed by a calibrated blinded examiner using a standardized clinical form (adapted from Peroz et al.), including: denture base extension and border molding accuracy, bilateral balanced occlusion, retention by vertical traction test (good/moderate/deficient), stability during mandibular movements, phonetic evaluation (/s/, /z/, /f/), and need for clinical adjustments.	At insertion, 2-month control of each denture set (Months 0, 2, and 4)
Maximum Masticatory Force	Relative occlusal force intensity and distribution recorded by the T-Scan digital occlusal analysis system (Tekscan Inc., Norwood, MA, USA) during maximum voluntary clenching. Parameters: total maximum force (relative units), right/left hemiarcade distribution, anterior/posterior distribution.	At insertion, 2-month control of each denture set (Months 0, 2, and 4); additionally at follow-up intervals during 12-month wear monitoring (from Month 2 / Set 2 insertion)
Denture Wear - Volumetric Surface Loss	Volumetric loss (mm³) of occlusal surfaces quantified by 3D superimposition (best-fit alignment) of STL models obtained by intraoral or laboratory scanning. Baseline scan obtained at delivery of each denture set. Longitudinal monitoring of Set 2 wear conducted over 12 months from its insertion.	Baseline (Month 2, Set 2 insertion); follow-up scans at scheduled intervals through Month 14 (12 months from Set 2 insertion)
Correlation Between Maximum Masticatory Force and Denture Wear	Pearson or Spearman correlation coefficient between T-Scan maximum force values and cumulative volumetric denture wear at each follow-up time point, for each workflow and overall.	Assessed at each follow-up time point during the 12-month wear monitoring period (Month 2 through Month 14)

Collaborators and Investigators

• Sponsor: Universidad de Especialidades Espiritu Santo
• Investigators: Study Director: Pablo Benitez, PhD, Universidad de Especialidades Espiritu Santo

Publications and helpful links

General Publications

• Garcia-Zea E, Revilla-Leon M. Digital workflow for fabricating printed complete dentures by integrating the true horizontal plane for articulator mounting and virtual patient integration. J Prosthet Dent. 2026 May;135(5):927-932. doi: 10.1016/j.prosdent.2025.09.018. Epub 2025 Oct 9.
• Garcia Zea E, Ullauri A, Benitez Sellan PL. Optimizing Complete Denture Fabrication With a Hybrid Analog-Digital Workflow: A Case Report. Case Rep Dent. 2025 Oct 3;2025:6761654. doi: 10.1155/crid/6761654. eCollection 2025.
• Revilla-Leon M, Ozcan M. Additive Manufacturing Technologies Used for Processing Polymers: Current Status and Potential Application in Prosthetic Dentistry. J Prosthodont. 2019 Feb;28(2):146-158. doi: 10.1111/jopr.12801. Epub 2018 Apr 22.
• Joda T, Zarone F, Ferrari M. The complete digital workflow in fixed prosthodontics: a systematic review. BMC Oral Health. 2017 Sep 19;17(1):124. doi: 10.1186/s12903-017-0415-0.
• Fenlon MR, Sherriff M. Investigation of new complete denture quality and patients' satisfaction with and use of dentures after two years. J Dent. 2004 May;32(4):327-33. doi: 10.1016/j.jdent.2004.01.007.
• Emami E, de Souza RF, Kabawat M, Feine JS. The impact of edentulism on oral and general health. Int J Dent. 2013;2013:498305. doi: 10.1155/2013/498305. Epub 2013 May 8.

Study record dates

Study Major Dates

• Study Start (Estimated): June 2, 2026
• Primary Completion (Estimated): October 15, 2026
• Study Completion (Estimated): October 30, 2027

Study Registration Dates

• First Submitted: May 31, 2026
• First Submitted That Met QC Criteria: May 31, 2026
• First Posted (Actual): June 4, 2026

Study Record Updates

• Last Update Posted (Actual): June 4, 2026
• Last Update Submitted That Met QC Criteria: May 31, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: complete denture; digital workflow; hybrid workflow; complete edentulous
• Other Study ID Numbers: 0922634274; 0991275878001 (Other Identifier: UEES)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Individual participant data that underlie the results reported in the published article, after de-identification, will be shared.
• IPD Sharing Time Frame: Beginning 6 months after article publication.
• IPD Sharing Access Criteria: Researchers who provide a methodologically sound proposal. Requests should be directed to the principal investigator.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No