Radiographic and Clinical Evaluations of Mandibular Implant-Supported Overdentures Supported by Conventional and Zirconia CAD/CAM Bars: A Randomized Clinical Trial

February 17, 2026 updated by: Sara Mohamed Fakhry Meligy Mohamed

Evaluation Of Mandibular Implant-Supported Overdenture: A Comparative Study of Conventional Bar Versus Zirconia CAD/CAM Bars

This randomized clinical trial aimed to evaluate the radiographic and clinical evaluations of mandibular implant-supported overdentures supported d by two different bar materials。 Completely edentulous patients received two implants in the mandibular canine region and were rehabilitated with overdentures supported by a conventional cobalt-chromium bar and a zirconia CAD/CAM bar。 Radiographic marginal bone loss around implants, crestal bone height changes posteriorly and clinical peri-implant parameters were assessed at baseline,6 months, and 12 months to compare the performance of both bar materials。

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This randomized clinical trial was conducted to compare the radiographic and clinical outcomes of mandibular implant-supported overdentures supported by conventional cobalt-chromium bars and zirconia CAD/CAM bars。 Eligible completely edentulous patients were selected according to predefined inclusion and exclusion criteria。

All participants received two endosseous dental implants placed in the mandibular canine regions following a standardized surgical protocol。 After a healing period, patients were randomly allocated into two groups。 In the first group, overdentures were supported by using a conventional cast cobalt-chromium bar, while in the second group, overdentures were supported by using a zirconia CAD/CAM-fabricated bar。

Radiographic evaluations of marginal bone loss around implants and crestal bone height changes posteriorly were performed using cone beam computed tomography and clinical peri-implant parameters, including pocket depth, plaque index, bleeding index, and mobility were evaluated at baseline,6 months and after 12 months。

The primary outcome of this study was the evaluation of radiographic marginal bone loss around implants and crestal bone height changes posteriorly, while secondary outcomes included peri-implant soft tissue health parameters。 The collected data were statistically analysed to compare bone stability and clinical performance associated with the two bar materials over the observation period。

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
12

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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
    • Nasr City
      • Cairo, Nasr City, Egypt
        • Faculty of Dental Medicine for Girls, Al-Azhar 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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • • Patients age range was between 50-60 years old.

    • Only male patients were selected to participate in this study.
    • All patients were apparently free from any systemic or debilitating diseases that might affect bone metabolism or delay post-operative healing.
    • Patients were free from any temporo-mandibular joint disorders.
    • Patients were free from any neuromuscular or bony disorders, and medically free from any neurologic disorder affecting the neuro-muscular system.
    • Patients' residual alveolar ridges were covered with firm, healthy mucosa, free from any signs of inflammation, ulceration, or flabby tissue.
    • Mandibular edentulous alveolar ridge areas had sufficient width and height of alveolar bone.
    • Patients exhibited Angle Class I maxillo-mandibular relationship and sufficient inter-arch space.
    • Patients had good oral hygiene.
    • A period of at least six months up to one year had elapsed from the last extraction.

Exclusion Criteria:

  • • Patients with systemic diseases that might affect bone quality, contribute to bone resorption, increase surgical risk, or delay/complicate post-operative healing.

    • Patients with parafunctional habits such as bruxism, clenching, or grinding.
    • Patients with residual ridge covered by inflamed, ulcerated, or flabby mucosa.
    • Patients with inadequate inter-arch space.
    • Patients with abnormal tongue behavior and/or size.
    • Patients with xerostomia or excessive salivation.
    • Heavy smoker patients and alcoholic patients.

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: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Conventional Cobalt-Chromium Bar
participants received mandibular implant-supported overdentures supported by a conventional cast cobalt-chromium bar
Device: Cobalt-Chromium Bar Attachment
A conventional cast cobalt-chromium bar used to retain a mandibular implant-supported overdenture
Experimental: Zirconia CAD/CAM Bar
participants received mandibular implant-supported overdentures supported by a Zirconia CAD/CAM-fabricated bar
Device: Zirconia CAD/CAM Bar Attachment
A zirconia CAD/CAM-fabricated bar used to retain a mandibular implant-supported overdenture

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Marginal bone loss around Implants
Time Frame: Baseline,6 months, and 12 months
Radiographic assessment of marginal bone loss around mandibular implants and crestal bone height changes posteriorly using cone-beam computed tomography (CBCT)
Baseline,6 months, and 12 months
Posterior crestal bone height changes of the mandibular ridge
Time Frame: Baseline,6months,12months
Radiographic assessment of posterior crestal bone height changes of the mandibular ridge using cone-beam computed tomography (CBCT)
Baseline,6months,12months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Peri-Implant probing depth
Time Frame: Baseline,6 months, and 12 months
Peri-implant probing depth measured using a calibrated periodontal probe
Baseline,6 months, and 12 months
plaque index around implants
Time Frame: Baseline, 6 months, and 12 months
Plaque accumulation around implants assessed using Silness and Löe plaque index
Baseline, 6 months, and 12 months
Bleeding on probing around implants
Time Frame: Baseline, 6 months, and 12 months
Bleeding on probing around implants assessed using a calibrated periodontal probe
Baseline, 6 months, and 12 months
Implant mobility
Time Frame: Baseline, 6 months, and 12 months
Implant mobility evaluated using clinical manual assessment (two rigid instrument technique)
Baseline, 6 months, and 12 months

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Sara Mohamed Fakhry Meligy Mohamed

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 18, 2022

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 17, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 19, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 3, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 17, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
February 24, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
February 24, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 17, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • P-PR-22-02

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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