Volumetric resorption of the alveolar ridge often occurs in both horizontal and vertical directions following tooth extraction. There is a specific lack of evidence for alveolar ridge reconstruction at molar and premolar sites with severe bone resorption. This randomized controlled trial used 3D and linear analyses to evaluate volumetric changes of the alveolar bone following alveolar ridge reconstruction (ARR) at molar and premolar sites with severe bone resorption as compared to unassisted socket healing before implant placement. A total of 31 patients (15 men, 16 women) with > 50% hard tissue loss in one or more socket walls were recruited and randomized into either a test group (postextraction ARR using deproteinized bovine bone mineral with 10% collagen [DBBM-C] and platelet-rich fibrin [PRF] with a resorbable collagen membrane) or a control group (natural healing after extraction). The clinical, linear, and volumetric implant-related and patient-reported outcomes were analyzed after 4 months of healing. Linear bone assessments revealed significantly greater ridge width gains in the test group (25% in the mesial, midfacial, and distal aspects) and less reduction of vertical bone ridge than in the control group (P < .05). Further, volumetric bone remodeling was significantly higher in the test group (35.1% ± 34.9% for ARR, 14.2% ± 12.8% for control; P < .05). Patient-reported discomfort and keratinized mucosal changes were comparable between groups. ARR with a combination of DBBM-C, PRF, and a resorbable membrane at posterior sites with a severe socket wall deficiency (> 50% bone loss) is a safe and more capable therapeutic method when compared to natural healing and unassisted sockets. Collectively, the present analyses demonstrate that ARR represents an efficient method to maintain and augment crestal bone at posterior extraction sites with severe bone defects when assessed after 4 months of healing.