This clinical and histologic case series aims to evaluate a novel flapless approach to alveolar ridge reconstruction (ARR) of compromised extraction sockets by means of collagenated xenograft sealed with three resorbable layers of hole-punched membrane. Eight postextraction sockets without buccal and/or palatal bone walls and with adjacent natural teeth from eight consecutive patients were included. Pretreatment CBCT scanning was performed. After debridement of the selected sites, a flapless grafting procedure was carried out, and the three-membrane protection was applied. After 6 to 17 months, at implant placement, a posttreatment alveolar ridge CBCT was taken, and a bone core biopsy sample was harvested for histologic and morphometric analyses. Clinical outcomes showed predictable horizontal bone regeneration in all postextraction sockets with good preservation of soft tissue architecture. Pretreatment ridge CBCT measurements showed limited bone width (2.6 ± 1.08 mm). Posttreatment measurements revealed adequate bone width (9.05 ± 1.29 mm) with a mean bone gain of 6.4 ± 1.34 mm. Histologic and morphometric analyses revealed the absence of inflammatory cells and the presence of 25.4% ± 8.7% of new bone and 31.8% ± 8.3% of graft particles inside the biopsy samples. Many graft particles were surrounded and interconnected by new bone, thus demonstrating the formation of a bone-graft network. Rare osteoclasts were found. This novel technique seems to be effective in treating alveolar sockets prior to implant placement, preventing inflammation and bone resorption and promoting bone regeneration.