El-mowafy D ⁱ. , Emera R ⁱⁱ and Hegazy S.A^{iii      i Doaa el-mowafy, BDS, Faculty of dentistry, Mansoura University ii Radwa Emera, Associate professor of Removable Prosthodontics, Faculty of dentistry, Mansoura University  iiiSalahAbdelFatahHegazy, Professor of Removable Prosthodontics, Faculty of dentistry, Mansoura University} Abstract: Purpose: To compare the effect of two versus three Implants assisted mandibular over denture with equator attachments on peri-implant tissue health. Materials and methods: six completely edentulous patients were selected for this study.Each patient received three implants in the midline and canine areas of the mandible using flapless two-stage surgical technique. This within-patient study was grouped as follow: Group Ι: patients received two- implant assisted mandibular over denture with OT Equator attachments. Group ΙΙ: The same patient received three- implant assisted mandibular over denture with OT Equator attachment after six months from exposure of the two implants. Peri-implant tissue health was evaluated at time of insertion (T0), 3 months (T1), 6months (T2) afterinsertion. Results: Non-significant difference between group І and group ІІregarding peri implant tissue health Conclusion: Three-implant as well as two-implant assisted mandibular over denture with equator attachments may have a favorable effect on peri-implant tissue health.