. There is little information on the degree of crestal bone loss around 4 inter-foraminal implant-retained mandibular overdentures (OVDs) and the amount of bone remodelling on the anterior maxilla and posterior mandibule on long-term function, particularly with different distributions.

Numerous studies confirm the successful use of implants to retain prostheses in the edentulous atrophic mandible. It has been recommended by some authors that clinicians should use 3 or 4 implants in situations that require increased retention, such as high muscle attachment or prominent mylohyoid ridge. LOCATOR attachment as a retentive component has several advantages over other systems, Such as: dual retention through both external and internal mating surfaces, a self-aligning feature which is helpful in guiding patients when placing their denture. There is little information on the degree of crestal bone loss around 4 inter-foraminal implant-retained mandibular overdentures (OVDs) and the amount of bone remodelling on the anterior maxilla and posterior mandibule on long-term function, particularly with different distributions.

Inclusion Criteria:

• Patients with 4 implants in the inter-foraminal region.
• Patients treated by staff and students in the Master's program in Prosthodontics Department according to the following criteria:
• Edentulous maxilla and mandible for at least 1 year.
• Problems with retention and stability of the mandibular denture.
• Mandibular bone height between 15 and 25 mm.

Exclusion Criteria:

• Patients with relative contraindications, such as
• A history of para functional habits.
• Smokers more than 10 cigarettes per day.
• alcoholism.
• Patients with a history of radiation therapy in the head and neck region . • Patients within intravenous administrated bisphosphonates., chemotherapy, and mental disorders that could jeopardies their co-operation.

above 60

10 patients in each group. total number of patients 20.

just by contacting the corresponding author