Compare the Difference in Occlusal Force Distribution and Denture Retention Using 2 Different Denture Base Materials in Implant Retained Overdenture

November 25, 2025 updated by: Noha Taha Kamel Taha Alloush, Al-Azhar University

Impact of Wearing Two Different Implant Retained Mandibular Overdentures on Occlusal Force Distribution and Denture Retention (Randomized Clinical Trial)

The global increase in the aging population has led to a rise in total edentulism, which remains a major public health concern. two-implant-retained mandibular overdentures have been regarded as the standard of care, offering superior retention, stability, comfort, and masticatory efficiency compared to conventional dentures. Among available attachment systems-bar, ball, stud, and magnet-the Equator attachment has gained popularity due to its low vertical profile, suitability for limited inter-occlusal space, and ease of handling.

Assessment of masticatory performance and occlusal balance can be objectively measured using devices such as bite force analyzers and the computerized T-Scan system, which quantifies occlusion and disocclusion times.

Conventional heat-cured polymethyl methacrylate (PMMA) remains the most widely used denture base material; however, it has mechanical and biological limitations. Flexible denture base materials have been introduced to overcome these drawbacks by enhancing adaptation, distributing occlusal loads more evenly, and improving comfort and retention.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Detailed Description

24 Patients will be randomly and equally divided into two treatment groups:

  1. Group 1: Each patient in this group will receive conventional maxillary and mandibular complete dentures made of heat-cured acrylic resin PMMA. In the mandible, two implants were inserted in the symphyseal area and retained by equator attachments.
  2. Group 2: Patients in this group received the same type of treatment as the patients in group 1, but the mandibular overdentures were made of the flexible acrylic resin "breflex" The present study will be performed to compare the difference in retention, occlusal force distribution, occlusion and disocclusion time, and bite force for implant retained mandibular over denture using PMMA and flexible dentures base materials

Study Type

Interventional

Enrollment (Actual)

24

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

  • Egypt
      • Cairo, Egypt, 4470351
        • Cairo University

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

Yes

Description

Inclusion Criteria:

  1. All patients age must range from 60-70 years old.
  2. All patients' ridges should be covered with firm mucosa free from any signs of inflammation or ulceration and exhibit adequate height and width of the residual alveolar ridge.
  3. Patients should be free from any metabolic or bone disorder that contraindicate implant installation.
  4. All patients must have sufficient inter arch space

Exclusion Criteria:

  1. Patients with oral or systemic diseases.
  2. Patients with xerostomia or excessive salivation.
  3. Patients with parafunctional habits (bruxism or clenching).
  4. Heavy smoker or alcoholic patients.
  5. Patients with history of temporo-mandibular dysfunction.
  6. Patients with brain disorders or psychiatric disorders

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: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Mandibular complete dentures processed into heat cured acrylic resin
Mandibular complete dentures made of heat-cured acrylic resin (PMMA). In the mandible, two implants were inserted in the symphyseal area and retained by Equator attachments.
Procedure: Conventional acrylic resin denture
Mandibular complete dentures made of heat-cured acrylic resin (PMMA). In the mandible, two implants were inserted in the symphyseal area and retained by Equator attachments.
Experimental: Mandibular thermoplastic nylon denture
Mandibular overdentures were made of the flexible acrylic resin breflex, In the mandible, two implants were inserted in the symphyseal area and retained by Equator attachments.
Procedure: Flexible resin denture
Mandibular overdentures were made of the flexible acrylic resin breflex, In the mandible, two implants were inserted in the symphyseal area and retained by Equator attachments

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Occlusal force distribution
Time Frame: Follow up visits were scheduled at denture insertion, 6, and 12 months
Occlusal force distribution will be measured by T-Scan, The latest version (T-Scan III) provides a dynamic visual evaluation of a patient's occlusion from initial tooth contact to maximum intercuspation. The system records relative force values and allows objective quantitative evaluation of occlusal balance by recording numerical values for occlusion and disocclusion times
Follow up visits were scheduled at denture insertion, 6, and 12 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Retention of lower denture
Time Frame: Follow up visits were scheduled at denture insertion, 6, and 12 months
Retention of lower denture will be measured using digital force gauge, Retention will be measured using digital force gauge A digital force meter was used to measure denture resistance to vertical displacement (i.e., retention) by applying a pulling force on a metal hook located in the geometric center of each mandibular conventional denture that was identified on the lower cast at the intersection of three lines bisecting the angles of the triangle, formed by both retromolar pads and the midline. Measurement of mandibular denture retention: The patient was instructed to place his head on chin rest and occlusal plane was set parallel to the floor. Tongue freedom was checked then and three minutes seating time was allowed before taking the measurements. A vertical pulling force was applied using the metallic probe of the digital force-meter that was attached to the hook present at the geometric center of mandibular denture. Average value of six readings was recorded.
Follow up visits were scheduled at denture insertion, 6, and 12 months
occlusion time
Time Frame: Follow up visits were scheduled at denture insertion, 6, and 12 months
occlusion and disocclusion time will be measured by T-Scan, The latest version (T-Scan III) provides a dynamic visual evaluation of a patient's occlusion from initial tooth contact to maximum intercuspation. The system records relative force values and allows objective quantitative evaluation of occlusal balance by recording numerical values for occlusion times
Follow up visits were scheduled at denture insertion, 6, and 12 months
Biting force
Time Frame: Follow up visits were scheduled at denture insertion, 6, and 12 months
Biting force will be measured by bite force meter
Follow up visits were scheduled at denture insertion, 6, and 12 months
Disocclusion time
Time Frame: Follow up visits were scheduled at denture insertion, 6, and 12 months
will be measured by T-Scan, The latest version (T-Scan III) provides a dynamic visual evaluation of a patient's occlusion from initial tooth contact to maximum intercuspation. The system records relative force values and allows objective quantitative evaluation of occlusal balance by recording numerical values for disocclusion times
Follow up visits were scheduled at denture insertion, 6, and 12 months

Collaborators and Investigators

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

Sponsor

Al-Azhar University

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 (Actual)

September 1, 2024

Primary Completion (Estimated)

January 1, 2026

Study Completion (Estimated)

February 1, 2026

Study Registration Dates

First Submitted

November 18, 2025

First Submitted That Met QC Criteria

November 25, 2025

First Posted (Actual)

November 26, 2025

Study Record Updates

Last Update Posted (Actual)

November 26, 2025

Last Update Submitted That Met QC Criteria

November 25, 2025

Last Verified

November 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 28.4.24

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Study Protocol and Clinical Study Report

IPD Sharing Time Frame

Start Date: After publication End Date: 3 years

IPD Sharing Access Criteria

After publication through the corresponding author

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • CSR

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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