Implant-supported Maxillary Overdentures; a 15-years Evaluation

February 23, 2026 updated by: University Medical Center Groningen
  • Background Patients experiencing problems with their conventional maxillary denture can benefit from implant- retained overdentures. Bar-retained implant overdentures can be supported by 4 or 6 implants, splinted by a bar. Evidence on maxillary implant overdentures has been mostly short to medium term, non-comparing or retrospective. Even more, 15-years data of comparative studies are lacking. It is important to evaluate treatment outcomes, such as implant survival, peri-implant bone changes and patient satisfaction at the long-term.
  • Main research question The aim of this 15-years study is to evaluate a patient group treated 15 years ago in a prospective study with a maxillary overdenture on 4 or 6 implants in an edentulous maxilla. The primary objective of the study is to analyze marginal bone level changes by radiological assessments at 15-years follow-up. Secondary objectives are implant and overdenture survival, condition of peri- implant mucosa and patients' satisfaction.
  • Design (including population, confounders/outcomes) The study design is an observational study of a group of patients which were treated 15 years ago with dental implants and an overdenture in the maxilla because of problems with retention and stability with their conventional denture. Outcomes: primary outcome is the change in marginal peri-implant bone level 15 years after placing the overdenture. Secondary outcome measures will be implant and overdenture survival, peri-implant mucosa health and patients' satisfaction using a questionnaire.
  • Expected results Stable peri-implant bone levels, high implant and overdenture survival rate and satisfied patients.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

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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

• Introduction and rationale In patients who present persistent complaints with respect to their maxillary denture, providing implant support improves comfort, denture satisfaction and overall quality of life considerably and high implant survival rates are reported. Implant position, the number of implants and bone volume are all factors that presumably influence success of both the maxillary overdenture and the implants.

Four- and 6-implant bar-supported maxillary overdenture studies report successful short and medium-term results, indicating that these treatment modalities are comparable and favourable. However, there is considerable heterogeneity with respect to patient and treatment variables within studies reporting on maxillary overdentures in general and four versus six implants in particular, with a lack of high quality long term data as well.

The aim of the present study is to report long term results of bar-supported maxillary implant overdentures on four and six anterior implants for which various clinical surgical and prosthetic outcome measures and subjective, patient-reported parameters are described and compared. Evidence on maxillary IOD attachment systems has been mostly short to medium term, non-comparing or retrospective and therefore inconclusive. This underlines the need for studies comparing different attachment systems with a longer follow-up.

The study design is an observational study to compare treatment outcomes of fully edentulous patients with maxillary IODs, supported by four or six implants. Patients were treated 15 years ago with dental implants and an overdenture in the maxilla because of problems with retention and stability with their conventional denture. Outcomes: primary outcome is the change in marginal peri-implant bone level 15 years after placing the overdenture. Secondary outcome measures will be implant and overdenture survival, peri-implant mucosa health and patients' satisfaction using a questionnaire.

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.
Observational

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.
116

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

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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

Sampling Method

Non-Probability Sample

Study Population

Patients who were treated 15 years ago with dental implants and an overdenture in the maxilla because of problems with retention and stability with their maxillary conventional denture.

Description

Inclusion Criteria:

  • Fully edentulous patients or patients with an overdenture in the mandible, who were referred to the Department of Oral and Maxillofacial Surgery (University Medical Center Groningen, the Netherlands) 15 years ago, because they suffered from a lack of retention and stability of the upper denture;

At the time of treatment:

  • Edentulous in the maxilla for at least one year;
  • Sufficient bone volume in height in the anterior or posterior region of the maxilla to place the implants;
  • The patient was 18 years or older;
  • Sufficient interocclusal space for placement of an overdenture with attachment system;
  • The patient was capable of understanding and giving informed consent.

Exclusion criteria at the time of treatment:

  • Patients with American Society of Anesthesiologists score (ASA score) ≥ III;
  • Patients who were smoking;
  • Patients with a history of radiotherapy in the head and neck region;
  • Patients with a history of pre-prosthetic surgery or previous implant placement in the maxilla.

Exclusion Criteria:

None

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

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
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.
Maxillary overdenture supported by dental implants
Patients with an edentulous maxilla who were provided with dental implants, a bar retention system and an overdenture
Device: Maxillary overdenture supported by dental implants
Maxillary overdenture supported by dental implants

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 in peri-implant marginal bone level
Time Frame: Through study completion, an average of 15 years
Comparison between peri-implant bone level at overdenture placement and follow-up time point in millimeters measured on intraoral radiograph
Through study completion, an average of 15 years

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
Implant and overdenture survival
Time Frame: Through study completion, an average of 15 years
Percentage of implants and overdentures present at follow-up time point
Through study completion, an average of 15 years
Patient satisfaction
Time Frame: 15 years
Patient satisfaction measured on a Visual Analogue Scale. Minimum =0 (extremely dissatisfied); Maximum = 100 (extremely satisfied)
15 years
Plaque score
Time Frame: 15 years
Plaque index from 0 to 3. Minimum = 0 (zero plaque visible); Maximum = 3 (abundant amount of plaque visible)
15 years
Gingival score
Time Frame: 15 years
Health of peri-implant mucosa described by Gingival index from 0 to 3. Minimum = 0 (healthy mucosa); Maximum = 3 (very infected mucosa)
15 years
Pocket depth
Time Frame: 15 years
Probing depth in the peri-implant sulcus in millimeters measured with a periodontal probe
15 years
Bleeding score
Time Frame: 15 years
Bleeding in peri-implant sulcus after probing measured with a Bleeding index from 0 to 3. Minimum = 0 (no bleeding after probing); Maximum = 3 (abundance amount of bleeding after probing)
15 years

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.
University Medical Center Groningen

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: Henny J A Meijer, Professor doctor, University Medical Center Groningen

Publications and helpful links

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General Publications

Study record dates

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Study Major Dates

Study Start (Estimated)

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.
May 1, 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.
November 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.
November 1, 2026

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 23, 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 23, 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 27, 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 27, 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 23, 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

Additional Relevant MeSH Terms

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.
  • 15 years maxillary overdenture

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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