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

Not yet recruiting

Conditions

Intervention / Treatment

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

Observational

Enrollment (Estimated)

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

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

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
Intervention / Treatment
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

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

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

University Medical Center Groningen

Investigators

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

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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 (Estimated)

May 1, 2026

Primary Completion (Estimated)

November 1, 2026

Study Completion (Estimated)

November 1, 2026

Study Registration Dates

First Submitted

February 23, 2026

First Submitted That Met QC Criteria

February 23, 2026

First Posted (Actual)

February 27, 2026

Study Record Updates

Last Update Posted (Actual)

February 27, 2026

Last Update Submitted That Met QC Criteria

February 23, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID 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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