Mandibular Overdentures Retained by Four Locator Attachments Versus Four-Implant Bar Attachments

NCT07093853 | Recruiting

• 1 other identifier: ADMNF-00925
• Study Type: observational
• Target: 22
• Locations: 1 country
• Sites: 1

Brief 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. 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.

Conditions

Bone Loss

Outcome Measures

Primary Outcomes (1)

• Marginal Bone Loss (MBL)

  Crestal bone loss around dental implants

  10 years

Study Arms (2)

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.

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.

Other: Four Locator Attachments, Four Bar Attachment System

Interventions

Four Locator Attachments, Four Bar Attachment System OTHER

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.

Group I - Locator Attachments; Group II - Bar Attachments

Eligibility Criteria

• Age: 40 Years - 70 Years
• Sex: all
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

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.

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• Menoufia University: lead
• Mansoura University: collaborator

Study Sites (1)

Faculty of Dentistry

Al Mansurah, Menoufia, Egypt

RECRUITING

MeSH Terms

Conditions

Bone Diseases, Metabolic

Condition Hierarchy (Ancestors)

Bone Diseases; Musculoskeletal Diseases; Metabolic Diseases; Nutritional and Metabolic Diseases

Study Officials

• Mohammed El-Sawy, PhD

  Menoufia University

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Mohammed El-Sawy, PhD

CONTACT

00201061314522; Dr_sawy@windowslive.com

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: RETROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Dr

Study Record Dates

• First Submitted: July 22, 2025
• First Posted: July 30, 2025
• Study Start: January 1, 2024
• Primary Completion: August 1, 2025
• Study Completion: October 1, 2025
• Last Updated: July 30, 2025

Record last verified: 2025-07

Data Sharing

• IPD Sharing: Will not share

Locations

EG (1)