This study was performed to compare the effect of new design (Bullard) versus conventional telescopic crown on bone level (radiographically) of implant-retained mandibular overdentureThe study was carried out on twenty completely edentulous patients, with two interforaminally installed implants, on both canine regions. The first group received the resilient Bullard telescopic retainers and the second group received the rigid conventional telescopic retainers.In the first group, Bullard telescopic retainers were designed using Plastic castable patterns were screwed to the analogues, waxed up with milling wax and milled with milling machine to form 6 degree convergence, and then a castable retentive cap was retained to the burnout plastic abutments with wax, to form the primary crowns. The retentive cap has the same diameter as the implant platform.In the other group, conventional telescopic implant retained mandibular overdenture. Plastic castable patterns were screwed to the analogues, waxed up with milling wax and milled with milling machine then casted and screwd in the implant octa abutments, as a primary copings .the secondary copings costructerd over its and connected by a framework inserted in fitting surface of the denture.At the time of loading, amount of bone loss of both groups were tested using the digital xray with aiding of the software of Digora to testing the amount of bone loss. After the interval of three months, patients of both groups were recalled and the amount of bone loss was measured. The same was done after the interval of six months as well. After finishing the amount of bone loss finally; the collected data was tabulated and statistically analyzed.