This study clinically and histologically evaluated the new bone formation and soft tissue changes when an autogenous tooth-derived mineralized dentin matrix (DDM) graft covered with a free gingival graft (FGG) was used for alveolar ridge preservation, as compared to spontaneous healing. Using a split-mouth protocol, 14 consecutive patients who required two extractions of a single-rooted tooth in the maxillary arch were enrolled. In each patient, one extraction site was treated with DDM and FGG (test group), while the other extraction site was covered with FGG and healed spontaneously (control group). In both test and control sites, implant placement was performed after a 16-week healing period. Compared to baseline (immediately after tooth extraction), both treatments yielded statistically significant differences in some clinical parameters and in the bone micro-architecture within the augmented sites. However, the use of DDM with the FGG created greater new vital bone formation, more newly formed bone, and fewer dimensional tissue changes than spontaneous healing with FGG.