Objectives Implants with a triangular neck were recently introduced to limit peri‐implant bone loss. The primary objective of this randomized controlled trial was to compare peri‐implant bone changes of circular versus triangular cross‐section neck implants 1 year after loading. The secondary objectives were to assess buccal hard tissue thickness changes, Pink Esthetic Score (PES), and patient satisfaction. Material and methods Thirty four patients requiring replacement of the single, intercalated missing tooth of healed site for at least 4 months in the posterior maxilla were randomized into 2 groups according to the type of implant. Immediately after surgery and 1 year after final restoration, a cone beam CT (CBCT) was performed to assess proximal bone remodeling and buccal bone thickness. Peri‐implant soft tissue health, PES, and patient‐reported outcome measures (PROMs) were recorded. Results No implant loss occurred within the follow‐up period. The mean ± SD peri‐implant proximal bone loss 1 year after loading was 0.22 ± 0.30 mm for triangular and 0.42 ± 0.67 mm for circular implants necks (p = .25). Peri‐implant bone loss exceeding 2 mm was observed in a single implant in the circular neck group. Buccal bone thickness remained stable and did not differ different between the 2 groups. The peri‐implant soft tissue health, PES, and patient satisfaction were also comparable. Conclusions Within the limitations of the present study, patient clinical and radiographic outcomes did not differ between triangular and circular cross‐section neck implants in the posterior maxilla.