INTRODUCTION:Various grafting procedures and bone substitutes can be used to achieve optimum treatment outcome in cases with deficient bone volume. Recently, Mineralized Plasmatic Matrix (MPM) was introduced as an autologous blood product highly enriched in platelets and fibrin network in a liquid form combined with a bone substitute. OBJECTIVES: This study was conducted to compare the effect of mineralized plasmatic matrix (MPM) with and without collagen membrane as a bone regenerative material in anterior maxillary horizontal alveolar bone defect. MATERIAL AND METHODS: Sixteen patients with anterior maxillary horizontal alveolar defect were randomly divided into 2 equal groups. Delayed implant placement (Dentis s-clean system) was done for all patients followed by defect grafting with MPM in group 1 while in group 2 the defect was completely grafted with MPM then covered by collagen membrane .; All implants were loaded after 3 months. Postoperatively, patients were followed up at immediately postoperative and at 3 for 9 months to clinically assess peri-implant probing depth and implant stability using Osstell® and to radiographically evaluate bone density, crestal bone loss and buccal bone thickness using CBCT. RESULTS: There was no statistically significant difference in peri-implant probing depth, implant stability, bone density, periimplant bone loss and buccal bone thickness between the two groups. However, there was a statistically significant increase in implant stability, bone density and buccal bone thickness between follow up periods in each group. CONCLUSION: Our results proved that MPM provides a more compact, durable and stable structure that helps the formation of new bone tissue without the use of a covering collagen membrane. KEYWORDS: Horizontal alveolar bone defect, MPM, collagen membrane and platelets concentrate. RUNNING TITLE: Peri-implant bone regeneration using MPM with and without collagen membrane.