Purpose: To evaluate two pharmacologic antibiotic prophylaxis regimens and a control group of immunocompetent patients undergoing two-stage dental implant placement in a triple-blind randomized controlled clinical trial. Materials and Methods: From a group of 61 immunocompetent patients, 21 were randomly allocated into group 1 (G1) without antibiotic prophylaxis (control), 20 in group 2 (G2) with preoperative antibiotic prophylaxis (1 g amoxicillin 1 hour before the procedure), and 20 in group 3 (G3) with preoperative (1 g amoxicillin) and postoperative (500 mg every 8 hours for 5 days) antibiotic prophylaxis. Pain was assessed with the visual analog scale (VAS) and by considering the number of painkillers patients used. Infection was identified via the presence of pus and fistula. Patients were evaluated after 7, 14, 30, and 120 days. Implant failure (defined as mobility upon the application of manual torque) was evaluated after 120 days during the second surgical stage. Results: At the 7-day follow-up, pain intensity was less severe in the patients who had received antibiotics, with the G3 patients experiencing the least pain (P < .05). Infection was present in groups G1 (2 cases) and G3 (2 cases), but there was no statistically significant intergroup difference. Two implants failed, one in G1 and the other in G3. Conclusions: Based on the results of the present study, although the use of antibiotics reduced pain in the immediate postoperative period, it did not reduce infection rates and implant failure in immunocompetent patients.