Single-implant Versus Two-implant Mandibular Overdentures

February 16, 2026 updated by: Rola Shadid

Patient-reported Outcomes and Masticatory Performance of Mandibular Overdentures Retained by One Parasymphyseal Implant or Two Implants: Randomized Clinical Trial

This randomized controlled trial compares a mandibular overdenture retained by one implant placed in the parasymphyseal or canine region with a mandibular overdenture retained by two implants placed in the interforaminal region in completely edentulous adults. Primary outcomes are oral health-related quality of life, patient satisfaction, and masticatory performance measured by a two-color chewing gum mixing test, assessed at baseline before implant surgery and at 3, 6, and 12 months after overdenture insertion.

Study Overview

Status

Status

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

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

Eligible completely edentulous adults will be randomized to receive either one endosseous implant in the mandibular parasymphyseal or canine region on the preferred chewing side or two endosseous implants in the mandibular interforaminal region, followed by restoration with a locator-type attachment retained mandibular overdenture. Oral health-related quality of life, patient satisfaction, and masticatory performance assessed by a two-color chewing gum mixing test are collected at baseline before surgery and at 3, 6, and 12 months after overdenture insertion. Secondary outcomes include postoperative pain recorded during the early postoperative period, radiographic marginal bone level change, peri-implant clinical parameters, prosthetic maintenance events, and clinician chair time from implant surgery through overdenture insertion.

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 (Estimated)

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.
32

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 Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • Palestinian Territories
    • Palestine
      • Jenin, Palestine, Palestinian Territories, 240 jenin
        • Recruiting
        • Faculty of Dentistry/ Arab American University
        • Contact:

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
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Men and women ≥40 years.
  • ASA I-II; favorable general health or adequately controlled systemic disease (e.g., hypertension, diabetes).
  • Skeletal Class I relationship.
  • Completely edentulous mandible and maxilla.
  • Technically acceptable complete dentures in both jaws for ≥3 and ≤24 months; dissatisfaction limited to mandibular retention/stability.
  • Adequate anterior mandibular bone for implant ≥3.5×10 mm confirmed on CBCT; no bone augmentation needed.
  • Normal mucosal resilience (~2 mm displacement).
  • Implant sites healed ≥4 months since extraction.
  • Willingness to be randomized and attend follow-ups; written informed consent.
  • Primary stability target ≥25 N-cm.

Exclusion Criteria:

  • Uncontrolled systemic disease; neurodegenerative disease; osteoporosis requiring antiresorptives.
  • Chronic systemic antibiotics/steroids; bleeding disorders; active cancer therapy; metabolic bone disease; HIV.
  • Investigational drug use within 30 days.
  • Alcohol dependence/illicit drug use; xerostomia (stimulated flow <0.7 mL/min).
  • Heavy smoking >20 cigarettes/day.
  • TMD/orofacial pain; severe bruxism; moderate/severe cognitive impairment.
  • Prior implant therapy.
  • Non-adherence risk or inability to attend longitudinal visits.
  • Insufficient prosthetic space for attachment housing: inter-arch vertical distance <8.5 mm at parasymphyseal/canine region.
  • Concurrent participation in another interventional study.
  • Erosive lichen planus or other significant oral mucosal disease; head-and-neck irradiation history.
  • Mandibular pathology on CBCT (e.g., cyst, tumor).
  • Ridge dimensions <6 mm width or <10 mm height at planned sites.
  • Active intraoral infection.

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

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: Single-implant mandibular overdenture (parasymphyseal/canine, preferred chewing side)
One bone-level implant will be placed in the mandibular parasymphyseal/canine region on the preferred chewing side using a single-stage approach. A locator-type attachment (Sonator S) will be connected according to the manufacturer's instructions, and intraoral pick-up will be performed with cold-curing resin.
Procedure: Single-implant mandibular overdenture (parasymphyseal/canine region)
Placement of one endosseous implant in the mandibular parasymphyseal/canine region on the participant's preferred chewing side, followed by delivery of a mandibular overdenture retained with a standardized attachment protocol and follow-up schedule.
Active Comparator: Two-implant mandibular overdenture (interforaminal)
Two bone-level implants will be placed bilaterally in the mandibular interforaminal region (bilateral lateral incisor-canine area) using a single-stage approach. Locator-type attachments (Sonator S) will be connected according to the manufacturer's instructions, and intraoral pick-up will be performed with cold-curing resin.
Procedure: Two-implant mandibular overdenture (interforaminal)
Placement of two endosseous implants in the mandibular interforaminal region (bilateral lateral incisor-canine area), followed by delivery of a mandibular overdenture retained with the same standardized attachment protocol and follow-up schedule.

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
Change from baseline in Oral Health Impact Profile for Edentulous Adults (OHIP-EDENT) total score
Time Frame: Baseline (pre-surgery), 3 months after overdenture insertion, 6 months after overdenture insertion, and 12 months after overdenture insertion
Oral health-related quality of life (OHRQoL) will be assessed using the Oral Health Impact Profile for edentulous adults (OHIP-EDENT). OHIP-EDENT includes 19 items across 7 domains: functional limitation, physical pain, psychological discomfort, physical disability, psychological disability, social disability, and handicap. Each item is rated on a 5-point Likert scale from 0 ("never") to 4 ("very often"). Total score range is 0-76; lower scores indicate better oral health-related quality of life (OHRQoL).
Baseline (pre-surgery), 3 months after overdenture insertion, 6 months after overdenture insertion, and 12 months after overdenture insertion
Change from baseline in McGill Denture Satisfaction Questionnaire (MDSQ) total score
Time Frame: Baseline (pre-surgery), 3 months after overdenture insertion, 6 months after overdenture insertion, and 12 months after overdenture insertion.
McGill Denture Satisfaction Questionnaire (MDSQ) includes 8 core questions. Each item is scored on a 100-mm VAS (0 = "no satisfaction at all"; 100 = "complete satisfaction"). Total score = sum of 8 items (range 0-800); higher scores indicate greater satisfaction.
Baseline (pre-surgery), 3 months after overdenture insertion, 6 months after overdenture insertion, and 12 months after overdenture insertion.
Change from baseline in masticatory performance measured by two-color chewing gum mixing test (Variance of Hue [VoH])
Time Frame: Baseline (pre-surgery), 3 months after overdenture insertion, 6 months after overdenture insertion, and 12 months after overdenture insertion.
Masticatory performance will be assessed using the two-color chewing gum mixing test. Chewed specimens are imaged and analyzed using ViewGum® software to calculate the Variance of Hue (VoH; range 0-1). Lower VoH indicates better color mixing (better masticatory performance).
Baseline (pre-surgery), 3 months after overdenture insertion, 6 months after overdenture insertion, and 12 months after overdenture insertion.

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
Visual Analog Scale (VAS) for postoperative pain
Time Frame: 24 hours after implant surgery, 7 days after implant surgery, and 21 days after implant surgery.
Postoperative pain/discomfort will be measured using a Visual Analog Scale (VAS). The VAS has an intensity range from 0 to 100, where 0 indicates "no pain" and 100 indicates "worst pain." Higher VAS scores indicate worse outcome (greater postoperative pain/discomfort).
24 hours after implant surgery, 7 days after implant surgery, and 21 days after implant surgery.
Expected and Perceived Treatment Burden Questionnaire Score (overall and stage-specific)
Time Frame: Baseline (pre-surgery, expected burden); within 7 days after implant surgery (experienced surgical-stage burden); at overdenture insertion (experienced prosthodontic-stage burden).
Patient-reported treatment burden will be assessed using the Expected and Perceived Treatment Burden Questionnaire (20 items rated on a 4-point Likert scale: 1 = not burdensome at all to 4 = extremely burdensome); overall and stage-specific burden scores will be calculated as the mean item score (range 1-4), where higher scores indicate greater burden (worse outcome), and an expectation-perception discrepancy will be calculated for each stage as perceived burden - expected burden (positive values indicate greater burden than expected).
Baseline (pre-surgery, expected burden); within 7 days after implant surgery (experienced surgical-stage burden); at overdenture insertion (experienced prosthodontic-stage burden).
Marginal bone level (MBL) change around implants (mm)
Time Frame: Overdenture insertion (baseline), 3 months after overdenture insertion, and 12 months after overdenture insertion
Marginal bone level (MBL) will be measured on standardized periapical radiographs as the vertical distance (mm) from the implant platform to the first bone-to-implant contact at the mesial and distal aspects; for each implant and timepoint, mean MBL will be calculated as the average of mesial and distal measurements, and mean MBL change (mm) will be computed as the follow-up mean MBL minus the baseline mean MBL.
Overdenture insertion (baseline), 3 months after overdenture insertion, and 12 months after overdenture insertion
Implant survival
Time Frame: Up to 12 months after overdenture insertion.
Presence of implant in situ without removal.
Up to 12 months after overdenture insertion.
Peri-implant probing depth (PPD), mean per implant (mm)
Time Frame: Baseline (at overdenture insertion), 3 months after overdenture insertion, 12 months after overdenture insertion.
PPD will be measured at 4 sites/implant (mesial, distal, buccal, lingual) with a periodontal probe as the distance (mm) from the peri-implant mucosal margin to the base of the peri-implant sulcus; the implant-level outcome will be the mean of the four site measurements at each timepoint.
Baseline (at overdenture insertion), 3 months after overdenture insertion, 12 months after overdenture insertion.
Modified plaque index (mPI)
Time Frame: 3 months and 12 months after overdenture insertion.
Peri-implant plaque will be assessed at 4 sites/implant (mesial, distal, buccal, lingual) using a periodontal probe by visual inspection along abutment surfaces and scored using the Mombelli modified plaque index (0-3): 0 = no plaque; 1 = plaque detected on probing; 2 = plaque visible to the naked eye; 3 = abundance of soft matter; the implant-level outcome will be the mean of the four site scores per implant at each timepoint.
3 months and 12 months after overdenture insertion.
Bleeding on probing (BOP) per implant (%)
Time Frame: Baseline (at overdenture insertion), 3 months after overdenture insertion, 12 months after overdenture insertion.
BOP will be recorded at 4 sites/implant (mesial, distal, buccal, lingual) as present/absent after gentle probing; the implant-level outcome is the percentage of bleeding sites per implant (0-100%) at each timepoint.
Baseline (at overdenture insertion), 3 months after overdenture insertion, 12 months after overdenture insertion.
Prosthetic maintenance events and complications of implant-retained overdenture
Time Frame: Up to 12 months after overdenture insertion.
Number and type of prosthetic maintenance events and complications related to the mandibular implant-retained overdenture recorded from clinical charts through 12 months after overdenture insertion. Events will be summarized as (a) total number of events per participant and (b) number of participants with ≥1 event. Higher values indicate worse outcome (greater maintenance/complication burden).
Up to 12 months after overdenture insertion.
Treatment efficiency: total clinician chair time
Time Frame: From implant surgery through overdenture insertion.
Total clinician chair time (minutes) for surgical and prosthodontic procedures required to deliver the implant-retained mandibular overdenture. Lower values indicate greater treatment efficiency.
From implant surgery through overdenture insertion.

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.
Rola Shadid

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Rola M Shadid, BDS, MSc, Arab American 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.
February 16, 2026

Primary Completion (Estimated)

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.
July 1, 2026

Study Completion (Estimated)

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.
July 1, 2027

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).
January 26, 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 6, 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 13, 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 17, 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 16, 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.
  • AAUP IRB Ref: J-2025A/46/N.

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

De-identified individual participant data (including data dictionary/codebook) underlying the primary and secondary outcomes will be shared.

IPD Sharing Time Frame

Available beginning after publication of the primary 12-month results, for 3 years.

IPD Sharing Access Criteria

Available to qualified researchers upon reasonable request, submission of a methodologically sound proposal, and execution of a data-use agreement; data will be shared via secure file transfer.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF
  • 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

product manufactured in and exported from the U.S.

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.

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings