Raouf C*,Elsyad M** , Wassef F*** ,Habib A **** *BDS, MDS in removable prosthodontic **BDS,MDS,PHD in removable prosthodontic ***BDS,MDS,PHD in removable prosthodontic ****BDS,MDS,PHD in removable prosthodontic Abstract: Aim of the work:This research was carried out to clinically and radio graphically evaluate and compare the conventional method of implant placement with adequate parallelism to the distally tilted implant concept in  bar implant supported mandibular overdenture. Materials and methods:Six completely edentulous male patients were selected from outpatient clinic of Prosthodontic Department, Faculty of Dentistry,MansouraUniversity.Patients were divided into two groups, four implants were placed accordingly.Control group (CG ) ; the posterior implants were positioned in the first molar regions and parallel to the canine implants . The study group (SG); the tilted implants(30 degreesoff a line parallel to the occlusal plane) were positioned anterior to the mental foramen in the region of premolars.The implants were early loaded (after 6 weeks) and attached to the mandibular overdenture with bar attachment. Six weeks after insertion,the patients were recalled for check up and received the final bar supported overdentures. CBCT radio graphical evaluation for crestal alveolar bone height level was done. Peri-implant plaque index, gingival index, probing depth and implant stability by periotest  was carried out immediately after denture insertion (T0), 6 (T6) and 12 (T12) months of denture insertion. Results:1) Plaque scores significantly increased with advance of time at anterior implants for both groups and for posterior implants in the CG only. 2 )SG recorded significant higher gingival scores than CG at T12 only for anterior implants. Pocket depth significantly increased with time for both groups .3) SG showed more increase in pocket depth than CG .4) Vertical bone loss (VBL) significantly increased from T6 to T12 for both groups with a total  bone loss averaged 1.17 mm at implant positions at all sites.CG recorded significant higher VBL than SG. No significance difference was revelaed in marginal bone loss between axial and tilted implants in SG . Conclusion: within the limitation of this short term clinical study regarding the small sample size ,it could be concluded that distal inclination of posterior implants used to support mandibular 4-implant bar overdentures may be advantageous in terms of peri-implant marginal bone preservations compared to vertical implnt placed posterior to mental foramine .However , the later design is more favourable in terms of periimplant soft tissue health.