Objectives : This study was conducted to evaluate and compare marginal bone level for abutments of implant supported Kennedy class I partial overdenture using Telescopic Crowns versus acetal resin clasps direct retainers after 18 month of clinical use. Materials & methods : Ten male partially edentulous patients (Kennedy class I) with the premolars are the last standing abutments were selected and all patients were rehabilitated with metallic partial denture supported by two osseointegrated implants one on each side of the lower arch positioned in the area of second molar and were randomly divided into two equal groups according to type of abutments retainers ,Group I; Patients were rehabilitated with Tooth Implant Supported partial overdenture with two telescopic crowns ,Group II; Patients were rehabilitated with Tooth Implant Supported partial overdenture with two Acetal Resin clasps direct retainer on each side. Evaluation by measuring marginal bone level for main abutments was made at the time of insertion, after 6 month ,after 12 month and last after 18 month using radiographic evaluation. Results: partial overdentures retained by telescopic crowns showed significant increase in marginal bone loss as compared with Acetal resin clasps retainers. Conclusion: using tooth implant partial overdentures retained by Acetal resin clasps shows better effect on supporting structure as compared by partial dentures with telescopic crowns retainers.