The global increase in the aging population has led to a rise in total edentulism, which remains a major public health concern. two-implant-retained mandibular overdentures have been regarded as the standard of care, offering superior retention, stability, comfort, and masticatory efficiency compared to conventional dentures. Among available attachment systems-bar, ball, stud, and magnet-the Equator attachment has gained popularity due to its low vertical profile, suitability for limited inter-occlusal space, and ease of handling.

Assessment of masticatory performance and occlusal balance can be objectively measured using devices such as bite force analyzers and the computerized T-Scan system, which quantifies occlusion and disocclusion times.

Conventional heat-cured polymethyl methacrylate (PMMA) remains the most widely used denture base material; however, it has mechanical and biological limitations. Flexible denture base materials have been introduced to overcome these drawbacks by enhancing adaptation, distributing occlusal loads more evenly, and improving comfort and retention.

24 Patients will be randomly and equally divided into two treatment groups:

1. Group 1: Each patient in this group will receive conventional maxillary and mandibular complete dentures made of heat-cured acrylic resin PMMA. In the mandible, two implants were inserted in the symphyseal area and retained by equator attachments.
2. Group 2: Patients in this group received the same type of treatment as the patients in group 1, but the mandibular overdentures were made of the flexible acrylic resin "breflex" The present study will be performed to compare the difference in retention, occlusal force distribution, occlusion and disocclusion time, and bite force for implant retained mandibular over denture using PMMA and flexible dentures base materials

Inclusion Criteria:

1. All patients age must range from 60-70 years old.
2. All patients' ridges should be covered with firm mucosa free from any signs of inflammation or ulceration and exhibit adequate height and width of the residual alveolar ridge.
3. Patients should be free from any metabolic or bone disorder that contraindicate implant installation.
4. All patients must have sufficient inter arch space

Exclusion Criteria:

1. Patients with oral or systemic diseases.
2. Patients with xerostomia or excessive salivation.
3. Patients with parafunctional habits (bruxism or clenching).
4. Heavy smoker or alcoholic patients.
5. Patients with history of temporo-mandibular dysfunction.
6. Patients with brain disorders or psychiatric disorders

Study Protocol and Clinical Study Report

Start Date: After publication End Date: 3 years

After publication through the corresponding author