Dental implant treatment based on the concept of osseointegration [1] is now a widely accepted restorative treatment for fully and partially edentulous patients. In the earliest days of the use of osseointegrated implants, two different topographies were applied on the implant surfaces: a machined minimally rough titanium surface such as the Brånemark system and a rough microporous titanium plasma-sprayed surface such as the ITI system [2]. In clinical studies, the long-term (i.e., up to 20 years) survival rate of Brånemark-system implants was in the range of 80–99% [3,4,5] and that with ITI-system implants was 88–96% [6, 7].

Despite the high survival rates, implant-supported restorations are still subject to biological and mechanical complications. The focus in dental implant treatments has shifted from implant survival to (1) implant success, (2) peri-implant infection, and (3) long-term outcomes of prostheses. Since the increasing human life expectancy and most of the patients who undergo implant treatment are middle-aged (approx. 40–60 years old) [8, 9], the determination of these longitudinal clinical outcomes over decades will contribute to the evaluation of treatment alternatives.

The aim of this retrospective study was not only to evaluate the long-term outcomes of solid-screw implants wit