This study was designed to assess the use of enamel matrix derivative (EMD; Emdogain, Straumann) and alloplastic bone substitute (BoneCeramic [BC], Straumann) in postextraction alveolar sockets. A total of 45 patients requiring anterior single tooth extractions and subsequent implant placement were recruited and randomly assigned to one of three treatment groups. Postextraction sockets were filled with BC or BC + EMD, or were left to heal spontaneously. Tomographic dimensional changes were measured immediately following tooth extraction and at the 6-month follow-up. Computed tomographic (CT) scans were taken with a radiographic stent within 48 hours of extraction (CT1) and at 6 months (CT2). Paired comparisons related to the mean horizontal reduction of the vestibular crest (VC) showed significant differences between sockets left to heal spontaneously (Group 1) and the two groups filled with BC (Group 2) and BC + EMD (Group 3): 1.7 mm for Group 1 and 0.9 mm for Groups 2 and 3 (P < .05). Thus, the use of alloplastic bone substitute alone or with EMD resulted in better preservation of postextraction socket dimensions. No differences in socket preservation were found between Group 2 (BC) and Group 3 (BC + EMD).