Several Alveolar Ridge Preservation (ARP) procedures have been proposed over the years. The purpose of this study was to describe the new Modified Periosteal Inhibition (MPI) technique for ARP. Seven patients were enrolled (age range: 28–72 years old; 5 males, 2 females). In total, nine hopeless teeth were treated. Following the elevation of a full-thickness flap, atraumatic tooth extraction was conducted, preserving the buccal bone of the alveolar socket. OsteoBiol® Lamina Soft (Tecnoss®, Giaveno, Italy), 0.5 mm thick, was suitably shaped (8–10 mm in height, extending from the mesial and to the distal corners of the socket). The lamina was gently positioned between the buccal periosteum and the buccal bone plate. Tisseel® (Baxter Healthcare Corporation, Deerfield, IL, USA) was applied to seal the cortical membrane. The flaps were sutured with PTFE 4-0 (Omnia, Fidenza, Italy). Postoperative instructions were provided. Patients were strictly monitored during the follow-up. No early or late biological complications were experienced. Cone Beam Computed Tomography (CBCT) exams were performed at baseline and 4 months later. The thickness of the buccal cortical bone at baseline was 1.18 ± 0.57 mm. The pre-operative and post-operative ridge widths were 10.74 ± 1.54 mm and 11.16 ± 1.57 mm, respectively. A horizontal ridge increase of 0.41 ± 0.21 mm was observed during the healing period. At 4 months of healing, the bone volume was adequate for implant placement and no additional bone regeneration procedures were required. MPI technique was effective in preventing the horizontal contraction of the post-extraction socket. Further studies will be needed in the future to confirm our positive results.