Purpose: To retrospectively evaluate the influence of prosthetic features on marginal bone level changes around bone-level implants with an external hex connection. Materials and Methods: A total of 100 patients with 166 implants and cemented crowns were included. Demographic and clinical data were collected. Prosthetic features were radiographically evaluated, including emergence angle (EA), emergence profile (EP), crown-implant ratio (CIR), and abutment height. Marginal bone levels were measured on intraoral radiographs taken at baseline and after at least 1 year. The correlation between prosthetic features and marginal bone loss (MBL) was then investigated. Results: The mean follow-up time was 43.94 months. Implant length varied between 5 and 13 mm. The mean height of the abutments used was 1.55 mm. EA measured an average 30.62 degrees (± 13.20) mesially and 29.45 degrees (± 13.07) distally. The CIR was 0.99 (± 0.26). The mean MBL was 0.19 mm on the mesial side and 0.20 mm on distal side of the implants. Significant positive associations emerged between MBL and implant length (P < .005) and with EA (P < .05). A convex profile of the crown was shown to be associated with a higher distal MBL (P = .025) compared to concave and straight profiles.
