Bone LossNCT07093853
Mandibular Overdentures Retained by Four Locator Attachments Versus Four-Implant Bar Attachments
An observational study of Bone Loss, run by Menoufia University at 1 site in Egypt.
Trial summary
This 10-year retrospective study investigates residual ridge changes in edentulous patients treated with mandibular overdentures (ODs) retained by either four Locator attachments or a four-implant bar system. Read more about this study
- Who is it for?
- Ages 40 to 70 years
- Conditions the study is for
- Bone Loss
- What is being tested?
- Four Locator Attachments, Four Bar Attachment System
- How many people
- 22 participants
- Where
- 1 siteEgypt
- Study dates
- 1 Jan 2024to 1 Oct 2025
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 40 to 70 years
- All sexes
- Adult, Older adult
Study population: The study population consisted of completely edentulous patients who received mandibular overdentures retained by four dental implants placed in the interforaminal region. Patients were selected retrospectively based on having been treated with either four Locator attachments or a four-implant bar attachment system and followed for a minimum period of 10 years. All participants had similar implant positioning (lateral incisor and first premolar areas) and were free from systemic conditions that could affect bone healing or implant success. Inclusion criteria required good oral hygiene compliance and regular follow-up records. Exclusion criteria included uncontrolled systemic diseases, history of head and neck radiation, and lack of long-term follow-up data.
Who may be able to join
- Completely edentulous mandible and maxilla for at least 12 months.
- Four interforaminal dental implants placed in the lateral incisor and first premolar regions.
- Opposing maxillary complete denture constructed using a muco-compressive impression technique, with maximum denture base extension and lingualized occlusion.
- Mandibular bone height between 15-25 mm at the symphysis region as measured on panoramic radiograph.
- Minimum 10-year follow-up with adequate radiographic documentation.
Who cannot join
- Systemic diseases affecting bone metabolism.
- Parafunctional habits (e.g., bruxism).
- Smokers of more than 10 cigarettes/day or those with alcohol abuse.
- Patients with implant failures, missing follow-up data, or implants placed outside the interforaminal region.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Egypt1 site, 1 recruiting
- Recruiting
Faculty of Dentistry
Al Mansurah, Menoufia
Mohammed El-Sawy, PhD, 00201061314522, Dr_sawy@windowslive.com
About this study
Official title: Residual Ridge Changes in Mandibular Overdentures Retained by Four Locator Attachments Versus Four-Implant Bar Attachments: A 10-Year Retrospective Study
This 10-year retrospective study investigates residual ridge changes in edentulous patients treated with mandibular overdentures (ODs) retained by either four Locator attachments or a four-implant bar system. Although two-implant ODs are well established, four-implant configurations may offer enhanced stability and function. Locator and bar attachments are commonly used, but their long-term effects on bone resorption patterns-especially posterior mandibular and anterior maxillary resorption-remain unclear. By standardizing implant positions, this study aims to directly compare the two systems to help guide clinicians in selecting the most effective attachment type for long-term success.
Read the detailed description
Implant-supported mandibular overdentures (ODs) have become the preferred treatment for edentulous patients, particularly after the endorsement of this approach by the McGill and York consensus statements. Although the use of two implants is well established, emerging research supports the use of four implants to enhance denture stability, improve masticatory function, and better maintain the surrounding oral structures.
Among the available attachment systems, Locator and bar-retained attachments are the most frequently utilized, each offering specific benefits. Locator attachments are known for their simplicity, affordability, and ease of maintenance. In contrast, bar-retained systems provide more rigid splinting between implants and more even stress distribution. These systems differ biomechanically, especially regarding their impact on bone resorption in the posterior mandible, which plays a vital role in denture retention and function.
While some research has compared different attachment types, few studies have standardized implant number and position. Moreover, there is a lack of long-term comparative studies assessing four-implant mandibular ODs using both Locator and bar attachments. Critical outcomes such as posterior mandibular ridge resorption (PMandRR), marginal bone loss (MBL), and anterior maxillary ridge resorption (AMaxRR) must be examined to evaluate the long-term effectiveness and biomechanical performance of these attachment systems.
- Conditions
- Bone Loss
- Being tested
- Four Locator Attachments, Four Bar Attachment System
- Medical subject headings
- Bone Diseases, Metabolic
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Four Locator Attachments, Four Bar Attachment SystemOther
This study retrospectively evaluated two types of implant-retained mandibular overdenture attachment systems placed in edentulous patients over a 10-year period. All patients received four dental implants placed in the interforaminal region (lateral incisor and first premolar areas).
In the Locator group, each implant was restored with an individual Locator attachment, allowing for independent retention and easier hygiene access.
In the Bar group, the four implants were splinted together with a rigid metal bar, and the overdenture was attached using clips that engaged the bar, offering splinted support and enhanced load distribution.
Both interventions were designed to support mandibular overdentures and were compared in terms of their long-term effects on posterior mandibular ridge resorption, marginal bone loss around implants, and anterior maxillary ridge resorption.
| Study group | Role | What they receive |
|---|---|---|
| Group I - Locator Attachments | Patients received four implants were placed in the lateral incisor and first premolar regions. Overdentures were retained using unsplinted Locator attachments, processed chairside via direct intraoral pick-up, with vent holes to allow resin escape. These prostheses were implant-retained and tissue-supported. Receives: Other: Four Locator Attachments, Four Bar Attachment System | |
| Group II - Bar Attachments | Patient also received four implants in the same quadrilateral distribution. The implants were splinted with a custom-milled titanium bar, and overdentures were retained using clip attachments. These prostheses were designed to be fully implant-supported, minimizing soft tissue loading. Receives: Other: Four Locator Attachments, Four Bar Attachment System |
What is being measured
The primary outcome is the main question the study is designed to answer.
Marginal Bone Loss (MBL)
Crestal bone loss around dental implants
Measured: 10 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Jul 2025
- Study start1 Jan 2024
- Primary completion1 Aug 2025 (estimated)
- Study completion1 Oct 2025 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Bone LossStudies of the same condition, open and under way.
- More trials run by Menoufia UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Retrospective
- Enrolment
- 22 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Menoufia University
- Sponsor type
- University, hospital or other
- Collaborators
- Mansoura University
- Responsible party
- Principal investigator, Mohammed El-Sawy, Menoufia University
- Investigators
- Mohammed El-Sawy, PhD, Principal investigator, Menoufia University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07093853
- Sponsor's protocol ID
- ADMNF-00925
- Status last verified
- Jul 2025
- First submitted
- 22 Jul 2025
- Last updated
- 30 Jul 2025
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Upon reasonable request from the corresponding author
Study at a glance
From the registry record, last updated by the sponsor on 30 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Residual Ridge Changes in Mandibular Overdentures Retained by Four Locator Attachments Versus Four-Implant Bar Attachments: A 10-Year Retrospective Study
- ClinicalTrials.gov ID
- NCT07093853
- Acronym / sponsor ID
- ADMNF-00925
- Conditions
- Bone Loss
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 22 participants (estimated)
- Lead sponsor
- Menoufia UniversityUniversity, hospital or other
- Collaborators
- Mansoura University
- Study start
- 1 Jan 2024 (actual)
- Primary completion
- 1 Aug 2025 (estimated)
- Study completion
- 1 Oct 2025 (estimated)
- First posted
- 30 Jul 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This 10-year retrospective study investigates residual ridge changes in edentulous patients treated with mandibular overdentures (ODs) retained by either four Locator attachments or a four-implant bar system. Although two-implant ODs are well established, four-implant configurations may offer enhanced stability and function. Locator and bar attachments are commonly used, but their long-term effects on bone resorption patterns-especially posterior mandibular and anterior maxillary resorption-remain unclear. By standardizing implant positions, this study aims to directly compare the two systems to help guide clinicians in selecting the most effective attachment type for long-term success.
Detailed description
Implant-supported mandibular overdentures (ODs) have become the preferred treatment for edentulous patients, particularly after the endorsement of this approach by the McGill and York consensus statements. Although the use of two implants is well established, emerging research supports the use of four implants to enhance denture stability, improve masticatory function, and better maintain the surrounding oral structures.
Among the available attachment systems, Locator and bar-retained attachments are the most frequently utilized, each offering specific benefits. Locator attachments are known for their simplicity, affordability, and ease of maintenance. In contrast, bar-retained systems provide more rigid splinting between implants and more even stress distribution. These systems differ biomechanically, especially regarding their impact on bone resorption in the posterior mandible, which plays a vital role in denture retention and function.
While some research has compared different attachment types, few studies have standardized implant number and position. Moreover, there is a lack of long-term comparative studies assessing four-implant mandibular ODs using both Locator and bar attachments. Critical outcomes such as posterior mandibular ridge resorption (PMandRR), marginal bone loss (MBL), and anterior maxillary ridge resorption (AMaxRR) must be examined to evaluate the long-term effectiveness and biomechanical performance of these attachment systems.
Study design
- Observational model
- Cohort
- Time perspective
- Retrospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Group I - Locator Attachments | – | Other: Four Locator Attachments, Four Bar Attachment SystemPatients received four implants were placed in the lateral incisor and first premolar regions. Overdentures were retained using unsplinted Locator attachments, processed chairside via direct intraoral pick-up, with vent holes to allow resin escape. These prostheses were implant-retained and tissue-supported. |
| Group II - Bar Attachments | – | Other: Four Locator Attachments, Four Bar Attachment SystemPatient also received four implants in the same quadrilateral distribution. The implants were splinted with a custom-milled titanium bar, and overdentures were retained using clip attachments. These prostheses were designed to be fully implant-supported, minimizing soft tissue loading. |
Who may qualify
- Ages
- 40 to 70 years
- Sex
- All
- Age groups
- Adult, Older adult
- Study population
- The study population consisted of completely edentulous patients who received mandibular overdentures retained by four dental implants placed in the interforaminal region. Patients were selected retrospectively based on having been treated with either four Locator attachments or a four-implant bar attachment system and followed for a minimum period of 10 years. All participants had similar implant positioning (lateral incisor and first premolar areas) and were free from systemic conditions that could affect bone healing or implant success. Inclusion criteria required good oral hygiene compliance and regular follow-up records. Exclusion criteria included uncontrolled systemic diseases, history of head and neck radiation, and lack of long-term follow-up data.
Key inclusion criteria (5 listed)
- Completely edentulous mandible and maxilla for at least 12 months.
- Four interforaminal dental implants placed in the lateral incisor and first premolar regions.
- Opposing maxillary complete denture constructed using a muco-compressive impression technique, with maximum denture base extension and lingualized occlusion.
- Mandibular bone height between 15-25 mm at the symphysis region as measured on panoramic radiograph.
- Minimum 10-year follow-up with adequate radiographic documentation.
Key exclusion criteria (4 listed)
- Systemic diseases affecting bone metabolism.
- Parafunctional habits (e.g., bruxism).
- Smokers of more than 10 cigarettes/day or those with alcohol abuse.
- Patients with implant failures, missing follow-up data, or implants placed outside the interforaminal region.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Four Locator Attachments, Four Bar Attachment SystemThis study retrospectively evaluated two types of implant-retained mandibular overdenture attachment systems placed in edentulous patients over a 10-year period. All patients received four dental implants placed in the interforaminal region (lateral incisor and first premolar areas). In the Locator group, each implant was restored with an individual Locator attachment, allowing for independent retention and easier hygiene access. In the Bar group, the four implants were splinted together with a rigid metal bar, and the overdenture was attached using clips that engaged the bar, offering splinted support and enhanced load distribution. Both interventions were designed to support mandibular overdentures and were compared in terms of their long-term effects on posterior mandibular ridge resorption, marginal bone loss around implants, and anterior maxillary ridge resorption. | Other | Group I - Locator Attachments, Group II - Bar Attachments |
Primary outcome
Marginal Bone Loss (MBL)
Time frame: 10 years
Crestal bone loss around dental implants
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Jul 2025.
- Individual participant dataSharing planned: No. Upon reasonable request from the corresponding author
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Mohammed El-Sawy, PhD principal investigator
Menoufia University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Bone Loss, run by Menoufia University at 1 site in Egypt.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 30 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Egypt. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Mohammed El-Sawy, PhD (00201061314522, Dr_sawy@windowslive.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Marginal Bone Loss (MBL) (time frame: 10 years). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 30 Jul 2025.