PURPOSE: To compare the accuracy of chairside, fused deposition modeling (FDM) three-dimensional (3D)-printed surgical guides with that of stereolithographic guides for implant placement in single edentulous sites within a clinical setting. MATERIALS AND METHODS: A total of 28 participants with 30 single posterior edentulous sites were included. The sites were randomized into a FDM 3D-printed surgical guide group (test) or stereolithographic guide group (control) of equal size (n = 15). In both groups, digital implant planning was performed using data from cone beam-computed tomography and intraoral scans. The test group's surgical guides were fabricated using a chairside, FDM 3D-printer; those in the control group were fabricated using a light-curing 3D-printer. Postoperative intraoral scans were used to obtain the 3D position of the implants. Compared to preoperative design, the angular, 3D, mesiodistal, buccolingual and apicocoronal deviations at the implant shoulder and apex were recorded. RESULTS: The workflow for the design and chairside fabrication of implant guides was established. The mean angular deviations of the test and control group were (4.23 ± 2.38) ° and (4.13 ± 2.42) ° (p > .05), respectively. The respective 3D deviations at the implant shoulder were (0.70 ± 0.44) mm and (0.55 ± 0.27) mm (p > .05); those at the implant apex were (1.25 ± 0.61) mm and (1.11 ± 0.54) mm (p > .05). The mesiodistal, buccolingual, and apicocoronal deviations at the implant shoulder and apex did not significantly differ between the groups (p > .05). CONCLUSIONS: Implants for single posterior edentulous spaces were placed as accurately with the test guide as with the control. Further research under more complex situations involving multiple missing teeth is needed.