Background. After tooth extraction, alveolar bone resorption is inevitable. This clinical phenomenon challenges dental surgeons aiming to restore esthetic and function. Alveolar ridge preservation can be applied to minimize dimensional changes with a new socket grafting material, an autogenous dentin graft, produced by mechanically and chemically processing natural teeth. This study assessed the safety and efficacy of using autogenous dentin biomaterial in alveolar ridge preservation. Materials and Methods. Patients with nonrestorable maxillary anterior teeth bounded by natural sound teeth were included in this study. After a detailed clinical and tomographic examination, eligible participants were randomly allocated into two groups. The control group had spontaneous healing of extraction sockets. The study group had their extraction sockets filled with autogenous dentin biomaterial after processing their extracted retained roots with the KometaBio device. Standardized cone beam computed tomography (CBCT) scans were repeated four months later. A full-thickness mucoperiosteal flap reflection was achieved under local anesthesia to get core biopsies for histomorphometric analysis, and dental implants were placed at the same session. Results. A total of 32 eligible patients were included in this study ($n=16$ in each group). Both groups had significantly higher facial soft tissue thickness after four months than baseline ($p<0.05$). However, the study group showed statistically significant lesser dimensional changes than the control group according to the standardized CBCT scans. Furthermore, core biopsies confirmed an excellent remodeling of the autogenous dentin biomaterial in the study group. In comparison, only new thin bone trabeculae-filled sockets were in the control group. Conclusion. Autogenous dentin graft can be safely and successfully used for alveolar ridge preservation. Optimal graft remodeling histologically, better ridge dimensional stability, and uneventful wound healing support its clinical application. This trial is registered with TCTR20220615002.