Purpose: The aim of this study was to retrospectively evaluate the factors affecting facial peri-implant mucosa topography of posterior single implant-supported restorations. Materials and Methods: The cohort comprised 25 patients with a single implant-supported restoration with platform switching and Morse taper- connection implants. Patients were divided into three groups based on facial soft tissue topography. Patients of group A (n = 8), group B (n = 9), and group C (n = 8) had a facial peri-implant tissue margin at the level of, coronal to, and apical to the zenith of the facial gingival margins of the adjacent teeth, respectively. Variables possibly associated with the facial peri-implant tissue margin level were obtained from clinical measurements, periapical radiographs, and cone beam computed tomograms. Results: Implants in group C were placed in a more subcrestal position than implants of group B (1.50 ± 0.53 mm vs 0.44 ± 0.88 mm). Implants in group C had their platform in a more apical position in relation to the bone level of the adjacent teeth than implants of group B (3.45 ± 1.32 mm vs 1.53 ± 1.17 mm). The horizontal distance between adjacent teeth was greater for group C than for group A and group B (13.53 ± 2.37 mm vs 10.65 ± 2.09 mm and 9.82 ± 1.77 mm, respectively). Conclusion: In this study, facial peri-implant mucosa margins for implants in the posterior region with platform switching and a Morse taper connection were significantly affected by the distances from the implant platform to the buccal aspect of the ridge at the time of implant placement and from the implant platform to the bone level of the adjacent teeth and by the horizontal spaces between the adjacent teeth. Schlagwörter: bone loss, clinical study, dental implants, radiology, retrospective study, subcrestal