Single vs. Two Implants for Mandibular Overdentures

Inclusion Criteria: * patients with a class I Maxillo-mandibular jaw relationship * patients with residual ridges had normal morphology, were free from severe bony undercuts or flabby tissue, and were covered by firm mucoperiosteum. * A cone beam CT of the lower arch was made to detect the presence of pathological lesions, remaining roots, or impacted teeth in the arch and evaluate both bone quality and quantity, especially in the area of interest Exclusion Criteria: * patients with current chemotherapy or radiotherapy, bleeding disorders, uncontrolled diabetes * patients with a history of drug therapy that interferes with bone resorption or deposition (e.g., the prolonged use of glucocorticoids, antiresorptive medications, selective serotonin reuptake inhibitors, and proton-pump inhibitors), * Those with any physical reasons that could affect follow-up, psychiatric problems, heavy smokers, drug or alcohol addicts, immunocompromised patients, abnormal jaw relationship, inadequate inter arch space. * patients with temporomandibular disorders and para-functional habits (e.g., bruxing and clenching).