For this study, twenty patients were selected, and participants were randomly divided into two groups using random numbers produced in an Excel spreadsheet. Each patient got four implants in the mandibular canine and first molar sites, as well as the bar attachment.

The purpose of this study was to document and report patient satisfaction with mandibular implant overdentures with quadrilateral distribution and linear distribution. The null hypothesis was that patient satisfaction would not be different depending on the distribution type (quadrilateral or linear).

According to the bar design, all patients were classified into two equal groups: quadrilateral bar design (group I) and bilateral linear bar design (group II). Peri-implant marginal bone loss was evaluated immediately (T0) and after 2 years (T2) of overdenture insertion using a digital periapical X-ray.

Inclusion Criteria:

• have Angle's class I maxilla-mandibular relation
• sufficient inter-arch space
• a healthy, firm mucosa,
• enough residual alveolar ridges in the mandibular regions to support implants

Exclusion Criteria:

• neuromuscular disorder,
• excessive smoking,
• alcoholism,
• parafunctional habits
• systemic disorders affecting the bones
• history of head and neck radiation therapy.