Comparing Cobalt-Chromium Versus PEEK Secondary Telescopic Crowns on Implant Retained Mandibular Overdenture.

The aim of this randomized clinical trial was to compare I- The clinical behavior of implant retained removable overdenture using telescopic retention system fabricated using CAD\\CAM techniques where the effects of the different material combinations were examined in regard to: 1. Retention of the mandibular over-denture. 2. Plaque accumulation, presence of calculus, bleeding tendency, health of peri-implant mucosa and probing depth. II - The radiographic behavior regarding marginal bone level and bone density.