Accuracy of Full Arch Intraoral Scanning

Effect of Different Intraoral Scanning Approaches on the Passive Fit of Mandibular All-on-Four Screw-Retained Frameworks

Although an intraoral scanner IOS can offer the clinician a completely digital workflow, achieving trustworthy digital scans in edentulous jaws is challenging because of the lack of fixed anatomical landmarks. From this perspective, several methods have been proposed to improve the accuracy of digital scanning, however, related results remain inconclusive, and previously proposed devices have had limitations, such as bulkiness, excessive manufacturing requirements, and poor commercial applicability.

Thus, this study aims to clinically compare the effect of conventional versus photogrammetry intraoral scanning methods on the passive fit of mandibular all-on four screw-retained frameworks.

Study Overview

• Status: Active, not recruiting
• Conditions: Completely Edentulous
• Intervention / Treatment: Device: The Photogrammetry-assisted intraoral scanning; Device: The modified approach of splinting-assisted intraoral scanning; Device: Simple splinting-assisted intraoral scanning

Detailed Description

The current study will be designed to be a crossover, double-blinded randomized clinical trial. Eighteen edentulous patients will be selected to share in the study to be rehabilitated by screw-retained prostheses following the all-on-4 protocol. After guided implant surgery, patients will be immediately restored by screw-retained acrylic provisionals following the traditional denture conversion technique. The definitive prosthesis will be fabricated after osseointegration starting with the intraoral scanning procedure; each patient will be subjected to three different scanning methods that can enhance the existing IOS workflow; for group I, the Medit i600 will be used to obtain direct intraoral scans while the scan bodies are combined with extra photogrammetry system scanning assistance, for group II, Medit i600 direct intraoral scans will be obtained while applying basic simple splinting along with incorporating a unique tip in the scanning protocol and scanner software, for group III, Medit i600 direct intraoral classical scans will be obtained while applying only a basic simple splinting. The STL file obtained from the different scans will be sent directly to the dental laboratory and three CAD/Milled frameworks will be realized based on the acquired scans. The jigs' passivity will be tested in the patient's mouth by the single screw test followed by the screw resistance test and the screw resistance test parameter will be calculated. The results will be collected for statistical analysis.

• Study Type: Interventional
• Enrollment (Estimated): 16
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Abbasia
    • Cairo, Abbasia, Egypt, 11566
      • faculty of dentistry Ain-Shams university

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Patients having a completely edentulous lower arch that could be restored by fixed screw-retained implant prosthesis.
• Patients having a substantial bone height and width at prospective implant sites to install four standard-size implants following the all-on-4 protocol.
• Patients having Sufficient crown height space.

Exclusion Criteria:

• Patients with bad oral hygiene.
• Patients with limited mouth opening.
• Vulnerable groups.
• Uncooperative patients.
• Patients receiving or undergoing radiotherapy or chemotherapy. Patients with systemic diseases affecting bone metabolism. Smokers.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Simple splinting-assisted intraoral scanning; The Medit i600 direct intraoral classical scans will be obtained while applying only a basic simple splinting	Device: The Photogrammetry-assisted intraoral scanning; The Photogrammetry-assisted intraoral scanning; will be executed using the MUA-compatible ioConnect ® photogrammetry system components exactly in the same sequence as recommended by the manufacturer; Device: The modified approach of splinting-assisted intraoral scanning; The scan bodies will be mounted over the MUA and loosely connected with a power chain before the Medit scanner single-shot scanning procedure. Using the additional scan option in the Medit scanner software, another single-shot scan will be obtained and superimposed to the first scan yielding a color map that reflects the accuracy of the obtained scan and directs a highly precise final scan.
Experimental: modified splinting-assisted intraoral scanning technique; The Medit i600 direct intraoral scans will be obtained while applying basic simple splinting along with incorporating a unique tip in the scanning protocol and scanner software	Device: Simple splinting-assisted intraoral scanning; The Medit i600 direct intraoral classical scans will be obtained while applying only a basic simple splinting
Experimental: Photogrammetry-assisted intraoral scanning; The Medit i600 will be used to obtain direct intraoral scans while the scan bodies are combined with extra photogrammetry system scanning assistance.	Device: Simple splinting-assisted intraoral scanning; The Medit i600 direct intraoral classical scans will be obtained while applying only a basic simple splinting

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Clinical assessment of passive fit following the latest update of the one screw test	Three CAD/Milled frameworks for each subject will be realized based on the acquired scans. The passive fit of each framework will be assessed intraorally following the Sheffield test: The test Part I involves checking the fit of the framework using finger pressure then tightening one of the most distal abutment screws. when an accurate horizontal and perpendicular fit viewed under magnification (will be categorized as 3 or excellent). If a slight "shadow" or suspicion of a vertical discrepancy, exists between the framework and abutment, a satisfactory passive fit will be confirmed by part 2 of test; If a suspected fit discrepancy can be closed using a 13mm wide modelling wax strip, representing 20 KN/m2 pressure load without distorting, then the fit is deemed to be clinically acceptable (categorized as 2 or good). If the wax does distort or is unable to close the discrepancy, will be (categorized as 1 or poor). this categorization arbitrarily defined by authors.	six months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
objective assessment of clinical passive fit using the screw resistance test parameter	The screw resistance test will be used to objectively evaluate and compare the passive fit of the three frameworks for each subject by calculating the SR parameter as the difference of the rotation angles of each screw in the passive and the non-passive situations by the formula: SR = SR passive - SR non-passive.	six months

Collaborators and Investigators

• Sponsor: Ain Shams University

Study record dates

Study Major Dates

• Study Start (Actual): March 3, 2025
• Primary Completion (Estimated): September 3, 2025
• Study Completion (Estimated): December 3, 2025

Study Registration Dates

• First Submitted: March 3, 2025
• First Submitted That Met QC Criteria: March 5, 2025
• First Posted (Actual): March 25, 2025

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: March 11, 2025
• Last Verified: March 1, 2025

More Information

Terms related to this study

• Keywords: intraoral scanner; photogrammetry; full arch implant restorations; passive fit; one-screw test; screw resistance test
• Additional Relevant MeSH Terms: Mouth Diseases; Stomatognathic Diseases; Tooth Diseases; Mouth, Edentulous
• Other Study ID Numbers: FDASU-RecIR022544

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: still study not completed

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No