Passive Fit of Implant-Supported Complete-Arch Prostheses Using Digital Workflows (MFS03-Pdental)

January 8, 2026 updated by: Miguel Gómez Polo, Universidad Complutense de Madrid

Evaluation of Passive Fit in Implant-Supported Complete-Arch Prostheses Using Three Digital Workflows, Including an Automated AI-Assisted Protocol: A Randomized Clinical Trial

The goal of this clinical trial is to evaluate and compare three digital workflows for the fabrication of definitive implant-supported full-arch prostheses in adult patients requiring fixed implant rehabilitation.

The main questions it aims to answer are:

  • Does an automated AI-assisted digital workflow improve the passive fit of definitive full-arch implant-supported prostheses compared with manual and splint-guided alignment workflows?
  • Are there differences in marginal, geometric, mechanical, and radiographic passivity among the three digital workflows? Researchers will compare manual CBCT-STL alignment, splint-guided alignment, and automated AI-assisted CBCT-STL alignment to see if the degree of digital workflow automation affects the passive fit of definitive full-arch implant-supported prostheses.

Participants will:

  • Be adults (18 years and older) indicated for fixed implant-supported full-arch rehabilitation.
  • Receive a definitive, screw-retained, full-arch implant-supported prosthesis fabricated using one of the three assigned digital workflows.
  • Undergo standardized clinical and radiographic assessments at the time of definitive prosthesis placement to evaluate prosthesis passive fit.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This randomized controlled clinical trial aims to evaluate and compare the passive fit of definitive full-arch implant-supported prostheses fabricated using three different digital workflows with increasing levels of automation for implant position registration and prosthesis fabrication.

Full-arch implant-supported rehabilitations require a high level of precision to ensure passive fit between the prosthetic framework and the implant-abutment connections. Inadequate passive fit may lead to mechanical complications, biological overload, or long-term prosthetic failure. Digital workflows combining intraoral scanning (IOS) and cone-beam computed tomography (CBCT) have been introduced to improve accuracy; however, differences in data acquisition and dataset alignment strategies may influence the final prosthetic fit.

The study will include adult patients (18 years and older) indicated for fixed implant-supported full-arch rehabilitation in the maxilla or mandible. Eligible participants will be recruited from the Faculty of Dentistry of the Complutense University of Madrid and associated clinical centers. After providing written informed consent, participants will be randomly assigned in a 1:1:1 ratio to one of three digital workflows:

  1. Manual CBCT-STL alignment (MedicalFit 1.0): implant positions are obtained by combining intraoral scans and CBCT data, with dataset registration performed manually by the operator based on visual alignment of scan bodies.
  2. Splint-guided alignment (MedicalFit 2.0): a calibrated rigid reference splint with metallic cylinders is used to stabilize implant positions and assist manual dataset registration, aiming to reduce operator-dependent variability.
  3. Automated AI-assisted CBCT-STL alignment (MedicalFit 3.0 - Pdental): dataset registration and passivation are performed automatically by dedicated software using advanced algorithms for implant detection and alignment, without manual intervention.

All participants will receive a definitive, screw-retained, full-arch implant-supported prosthesis fabricated according to the assigned digital workflow. Prosthetic materials and clinical procedures will follow standard clinical practice. No outcome measures will be assessed during provisional prosthetic phases.

Passive fit will be evaluated exclusively at the time of definitive prosthesis placement using a standardized multi-assessment clinical approach performed at each implant-prosthesis connection.

Marginal passive fit will be assessed clinically by direct inspection using a calibrated periodontal probe. The presence or absence of marginal discrepancies between the prosthesis and the transepithelial abutment will be evaluated based on visual and tactile criteria, including the ability of the probe to penetrate the prosthesis-abutment interface.

Geometric passive fit will be evaluated using the modified Sheffield test. With all prosthetic screws loosened except for one distal screw, the presence of any lifting or separation of the prosthetic framework at the non-tightened connections will be assessed visually and tactually using an explorer probe.

Mechanical passive fit will be assessed through the tactile sensitivity of the passive screw test. Resistance perceived during screw tightening will be evaluated qualitatively to identify the presence of internal stresses or framework flexure during seating of the definitive prosthesis.

Radiographic passive fit will be assessed by measuring marginal gaps at the prosthesis-abutment interface on standardized periapical radiographs. Radiographic gaps will be quantified and classified using predefined ordinal thresholds to identify clinically relevant discrepancies.

Each assessment will be scored using an ordinal scale (0-2) based on predefined clinical criteria. To reflect clinical decision-making and ensure a conservative interpretation of prosthetic fit, a hierarchical aggregation rule will be applied. For each assessment dimension, the prosthesis-level score will be defined as the worst score observed among all implant-prosthesis connections. The global multi-assessment passive fit score (0-2) will then be defined as the worst score observed across all assessment dimensions.

Accordingly, if any implant-prosthesis connection exhibits a clinically relevant misfit in any assessment, the definitive prosthesis will be classified as non-passive. This approach reflects the clinical principle that lack of passive fit at a single connection compromises the overall prosthetic outcome.

The primary objective of the study is to determine whether increased automation in digital workflows improves the passive fit of definitive full-arch implant-supported prostheses. Secondary objectives include comparing marginal, geometric, mechanical, and radiographic passivity outcomes among the three workflows and exploring the relationship between workflow automation and prosthetic adaptation accuracy.

The study follows CONSORT guidelines and aims to provide clinically relevant evidence to support the optimization of digital workflows in full-arch implant-supported prosthetic rehabilitation

Study Type

Interventional

Enrollment (Estimated)

30

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Spain
    • Madrid
      • Madrid, Madrid, Spain, 28040
        • Recruiting
        • University Complutense of Madrid
        • Contact:
          • Miguel A Gomez-Polo, DDS, PhD, DDS
          • Phone Number: +34 91 394 2029
          • Email: mgomezpo@ucm.es

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Adults aged 18 years or older.
  2. Patients indicated for fixed implant-supported full-arch rehabilitation in the maxilla or mandible.
  3. Presence of clinically stable, osteointegrated titanium implants suitable for prosthetic rehabilitation.
  4. Absence of clinical or radiographic signs of peri-implant disease.
  5. Ability to understand the study procedures and provide written informed consent.
  6. Willingness and ability to attend all required clinical visits and evaluations.

Exclusion Criteria:

  1. Presence of peri-implant mucositis or peri-implantitis at the time of evaluation.
  2. Implant mobility or implant positioning that prevents proper prosthetic rehabilitation.
  3. Uncontrolled systemic medical conditions that could interfere with study participation or prosthetic treatment.
  4. Cognitive, psychological, or medical conditions that limit the ability to comply with study procedures.
  5. Inability to complete the required clinical evaluations or follow the study protocol, as judged by the investigator.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: CBCT-STL Alignment (Medicalfit 1.0)
Participants in this arm will receive a definitive, screw-retained, implant-supported full-arch prosthesis fabricated using a digital workflow based on manual alignment of CBCT and intraoral scan (STL) datasets. Scannable healing abutments (Tissue Shapers-IF; MedicalFit, Úbeda, Spain) will be connected to multi-unit abutments according to the manufacturer's instructions. An intraoral scan and a CBCT scan will be obtained and manually aligned by the operator during the CAD design stage using reference points visible in both datasets. Prosthetic framework passivation is performed manually during the CAD phase. The definitive prosthesis is designed and manufactured using CAD/CAM technology in monolithic zirconia (IPS e.max ZirCAD Prime; Ivoclar, Schaan, Liechtenstein). This workflow is fully operator-dependent and serves as an active comparator.
Procedure: CBCT-STL Alignment Workflow
This procedure consists of a fully digital workflow for fabricating a screw-retained, implant-supported full-arch prosthesis using manual alignment between CBCT and intraoral scan (STL) data. Scannable healing abutments (Tissue Shapers-IF; MedicalFit, Úbeda, Spain) are attached to multi-unit abutments torqued to 10 Ncm. A CBCT scan and an intraoral scan are acquired and manually aligned in CAD software using operator-defined reference points. Passive fit is adjusted manually during the CAD design stage. The definitive framework is milled from monolithic zirconia (IPS e.max ZirCAD Prime; Ivoclar, Schaan, Liechtenstein). This workflow is operator-dependent and serves as the control procedure.
Active Comparator: Splint-Guided Alignment (Medicalfit 2.0)
Participants in this arm will receive a definitive, screw-retained, implant-supported full-arch prosthesis fabricated using a digital workflow that incorporates a rigid reference splint with metallic abutment cylinders to assist manual dataset alignment. Scannable healing abutments (Tissue Shapers-IF; MedicalFit, Úbeda, Spain) are connected to multi-unit abutments. A calibrated rigid splint is intraorally adapted and connected to the abutment cylinders, and both intraoral and splint scans are obtained. The acquired datasets are imported into CAD software, where CBCT-STL registration is performed manually using the splint as a reference. The definitive prosthetic framework is designed and manufactured using CAD/CAM technology in monolithic zirconia (IPS e.max ZirCAD Prime; Ivoclar, Schaan, Liechtenstein). This workflow remains operator-dependent and serves as an active comparator.
Procedure: Splint-Guided Alignment Workflow
This procedure employs a rigid reference splint with metallic abutment cylinders to guide dataset alignment for full-arch prosthesis fabrication. Scannable healing abutments (Tissue Shapers-IF; MedicalFit, Úbeda, Spain) are connected to multi-unit abutments torqued to 10 Ncm. The splint is attached intraorally and scanned extraorally to capture implant positions. The splint and intraoral scans (STL) are imported into CAD software, where manual alignment is performed using the splint as a reference. The final monolithic zirconia framework (IPS e.max ZirCAD Prime; Ivoclar, Schaan, Liechtenstein) is designed and milled via CAD/CAM. This workflow is operator-dependent and used as an active comparator.
Experimental: Automated AI-Assisted CBCT-STL Alignment (Medicalfit 3.0)
Participants in this arm will receive a definitive, screw-retained, implant-supported full-arch prosthesis fabricated using an automated AI-assisted digital workflow. Scannable healing abutments (Tissue Shapers-IF; MedicalFit, Úbeda, Spain) are connected to multi-unit abutments according to the manufacturer's protocol. An intraoral scan and a CBCT scan are acquired and imported into dedicated AI-assisted software (Pdental; MedicalFit, Úbeda, Spain). The software automatically detects the scan bodies and performs CBCT-STL dataset alignment prior to CAD/CAM prosthesis fabrication. The definitive prosthesis is designed and manufactured using CAD/CAM technology in monolithic zirconia (IPS e.max ZirCAD Prime; Ivoclar, Schaan, Liechtenstein). This workflow minimizes operator involvement and represents the experimental intervention.
Procedure: Automated AI-Assisted CBCT-STL Alignment Workflow
This procedure uses AI-assisted software (Pdental, MedicalFit, Úbeda, Spain) to automate the alignment of CBCT and intraoral scan (STL) datasets for full-arch prosthesis fabrication. After placement of scannable healing abutments (Tissue Shapers-IF; MedicalFit), intraoral and CBCT scans are obtained. The software automatically detects healing abutments, performs CBCT-STL registration, and corrects deviations greater than 120 µm to achieve passive fit within clinically acceptable limits. The corrected digital model is exported in STL format for CAD design and CAM milling of a monolithic zirconia screw-retained prosthesis (IPS e.max ZirCAD Prime; Ivoclar, Schaan, Liechtenstein). This workflow minimizes operator dependency based on an AI-assisted automation. .

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Multi-assessment global passive fit score of definitive full-arch implant-supported prostheses
Time Frame: At definitive prosthesis placement

Passive fit of the definitive full-arch implant-supported prosthesis will be evaluated using a standardized multi-assessment clinical approach. Marginal, geometric (modified Sheffield test), mechanical (passive screw test sensitivity), and radiographic passive fit will be assessed independently at each implant-prosthesis connection.

Each assessment will be scored using an ordinal scale (0-2) based on predefined clinical criteria:

0 = no detectable discrepancy, indicating adequate passive fit;

1 = minor discrepancy, indicating a cl To obtain the prosthesis-level outcome, a conservative aggregation rule will be applied: for each assessment dimension, the prosthesis score will be defined as the worst score observed among all implant-prosthesis connections. The global multi-assessment passive fit score (0-2) will then be defined as the worst score observed across all assessment dimensions.
At definitive prosthesis placement

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Clinical marginal passive fit (probe assessment)
Time Frame: At definitive prosthesis placement

Marginal passive fit will be evaluated clinically by direct inspection using a calibrated probe to assess the presence of marginal discrepancies between the prosthesis and the transepithelial abutment. Outcomes will be recorded using an ordinal scale (0-2) based on visual and tactile criteria defined as follows:

0 = no visible gap and no probe penetration;

  1. = visible marginal discrepancy without probe penetration;
  2. = clinically detectable gap with probe penetration or visually, indicating lack of passive fit.
At definitive prosthesis placement
Radiographic marginal gap at the prosthesis-abutment interface
Time Frame: At definitive prosthesis placement

Marginal gaps between the definitive prosthesis and the transepithelial abutment will be evaluated on standardized periapical radiographs. Measured gaps will be classified using an ordinal scale (0-2) as follows:

0 = gap < 100 µm;

  1. = gap between 100 and 130 µm;
  2. = gap > 130 µm, indicating a clinically relevant misfit.
At definitive prosthesis placement
Geometric passive fit assessed by the modified Sheffield test
Time Frame: At definitive prosthesis placement

Geometric passive fit will be evaluated using the modified Sheffield test by tightening a single distal prosthetic screw and assessing the presence of lifting or separation at the non-tightened implant-prosthesis connections. Outcomes will be classified as follows:

0 = no visible or tactile separation;

  1. = slight visible separation without probe penetration;
  2. = clear separation with probe penetration, indicating absence of passive fit.
At definitive prosthesis placement
Mechanical passive fit assessed by passive screw test sensitivity
Time Frame: At definitive prosthesis placement

Mechanical passive fit will be evaluated qualitatively based on tactile resistance perceived during tightening of the prosthetic screws. Outcomes will be classified using an ordinal scale (0-2) defined as follows:

0 = smooth screw tightening without perceptible resistance;

  1. = mild or transient resistance without need for force;
  2. = clear resistance or framework flexure during tightening, indicating internal stress and lack of passive fit.
At definitive prosthesis placement

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Universidad Complutense de Madrid

Investigators

  • Study Director: Miguel A Gómez Polo, DDS, PhD, School of Dentistry, Complutense University of Madrid. Pza Ramon y Cajal S/N. 28040 Madrid, Spain

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

January 1, 2026

Primary Completion (Estimated)

December 1, 2026

Study Completion (Estimated)

March 1, 2027

Study Registration Dates

First Submitted

December 18, 2025

First Submitted That Met QC Criteria

December 18, 2025

First Posted (Estimated)

January 2, 2026

Study Record Updates

Last Update Posted (Actual)

January 9, 2026

Last Update Submitted That Met QC Criteria

January 8, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • 25/701-IC_P_CE

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared due to ethical and privacy considerations. The data collected include detailed clinical and radiographic information that could potentially allow re-identification of participants, even after de-identification. Data will be used solely for the purposes defined in the approved 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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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