AIM: This randomized clinical study aimed to assess bone height loss when using mandibular implant overdentures retained by two and four endosseous implants using the telescopic attachments. METHODS: Twelve completely edentulous patients were randomly allocated so that six patients were treated by telescopic implant overdenture retained by two implants (group A) and six patients were treated with overdentures retained by four implants (group B). Digital radiographic evaluation of bone height using Digora was made starting at the functional loading day followed by time intervals of 12 months. RESULTS: No implant loss during the healing period or after functional loading. Radiographic evaluation revealed a statistically significant difference was found between (Group A) and (Group B) were (p < 0.001). CONCLUSION: For bone loss, widely distributed four intraforaminal implants revealed more bone preservation than only two implants when using the telescopic attachments to support and retain an over dentures taking in consideration the type of the attachment will be used.