Jung RE, et al. - This split-mouth randomized controlled study was designed to evaluate radiographic dimensional changes after tooth extraction in posterior sites treated with a ridge preservation technique or left for spontaneous healing. Two treatment modalities were assigned to the post-extraction sockets: deproteinized bovine bone mineral (DBBM) with 10% collagen (DBBM-C) covered with a native bilayer collagen membrane (NBCM) (test group) and spontaneous healing (control group). Test and control group showed a bone loss compared to baseline in the Cone beam computed tomography analysis. However, the posterior ridge preservation technique using DBBM-C covered with a NBCM was noted to be a valid approach to reduce the amount of the radiographic loss in alveolar ridge dimensions.