Purpose: To evaluate marginal bone level change and accuracy of 4 immediately loaded maxillary implants placed utilizing a flapless guided surgery approach to support a maxillary overdenture retained with solitary attachments. Materials & Methods: Subjects with fully edentulous maxillae wearing complete dentures were included. All patients received 4 endosteal implants placed using a stereolithic, mucosa-supported surgical guide. Implants were immediately loaded following surgery with the maxillary overdenture using a solitary attachment system. Radiographic bone level change (RBLC) at 12-months following implant placement was the primary outcome variable. The implant survival rate, peri-implant clinical parameters, accuracy of implant position, prosthetic complications and patient-centered outcomes were the secondary outcome variables. Results: A total of 14 subjects accounting for 56 implants were enrolled and completed the study. Two implants failed with a cumulative survival rate of 96.4% at 12-months. The mean RBLC was 0.14 ± 0.36 (range=0 1.7 mm) and 0.31 ± 0.73 mm (range: 0-4.45 mm) at 6 and 12 months respectively. The delta RBLC was statistically significant from baseline to 6-months (p=0.005) and baseline to 12 months (p=0.002). The mean global angular deviation was 3.35 ± 1.945° with a range of 0.00-10.3°. The 3D offset at the platform and apex are 0.852 ± 0.483 mm (range: 0.19-2.32 mm) and 1.073 ± 0.611 mm (range: 0.26-2.65 mm), respectively. Conclusion: Within the study limitations, results indicate that immediately loaded four-guided implants supporting a maxillary overdenture with solitary attachments may be a suitable treatment option for the edentulous maxilla.