Clinical and radiographic assessment of circular versus triangular cross-section neck Implants in the posterior maxilla: A 1-year randomized controlled trial.

Abstract

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 1year after loading. The secondary objectives were to assess buccal hard tissue thickness changes, Pink Esthetic Score (PES), and patient satisfaction. Thirty four patients requiring replacement of the single, intercalated missing tooth of healed site for at least 4months in the posterior maxilla were randomized into 2 groups according to the type of implant. Immediately after surgery and 1year 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. No implant loss occurred within the follow-up period. The mean±SD peri-implant proximal bone loss 1year after loading was 0.22±0.30mm for triangular and 0.42±0.67mm for circular implants necks (p=.25). Peri-implant bone loss exceeding 2mm 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. 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.