To test the non-inferiority of demineralized bovine bone mineral (DBBM) compared to DBBM with 10% collagen (DBBM-C) for maintenance of bone volume after tooth extraction in the anterior maxilla. Sixty-six patients were randomly treated with DBBM or DBBM-C, both of which were covered with a collagen matrix for ridge preservation in the anterior maxilla. Cone-beam computed tomographic analysis was performed immediately and 4months after treatment. The primary outcome, for which non-inferiority of DBBM was tested, was change in the horizontal ridge width 1mm below the buccal alveolar crest (HW-1) 4months after extraction. Four months after extraction, HW-1 measured -1.60mm±0.82mm for DBBM-C, while the DBBM group showed a mean loss of -1.37mm±0.84mm (p=0.28, 0.23 [95% CI: -0.19; 0.64]). The horizontal ridge width at 3mm (HW-3) showed -0.98mm (±0.67mm) for DBBM-C and -0.84mm (±0.62mm) for DBBM (p=0.40, 0.12 [95% CI: -0.19; 0.45]), and the horizontal ridge width at 5mm (HW-5) showed -0.67mm (±0.47mm) for DBBM-C and -0.56mm (±0.48mm) for DBBM (p=0.36, 0.11 [95% CI: -0.13; 0.34]). The present clinical trial demonstrated non-inferiority of DBBM compared to DBBM-C for maintenance of alveolar bone volume 4months after tooth extraction in the anterior maxilla.