Implant Surface Characteristics and Peri-Implant Outcomes: A Systematic Review of Clinical and Microbiological Evidence

<b>Background:</b> Implant surface characteristics have been extensively investigated for their potential influence on osseointegration and peri-implant tissue stability. However, their actual clinical relevance in the prevention and progression of peri-implant diseases remains controversial. This systematic review aimed to synthesize the available clinical and microbiological evidence on the impact of different implant surface characteristics and surface modifications on peri-implant outcomes. <b>Materials and Methods:</b> Conducted according to PRISMA and registered in PROSPERO, an electronic search of PubMed, Scopus, and Web of Science (2015-2025) identified clinical studies assessing associations between implant surface characteristics/modifications and peri-implant clinical, radiographic, microbiological, or biomolecular outcomes. Risk of bias was evaluated using ROBINS-I. <b>Results:</b> Thirteen studies (randomized, controlled, and cohort designs) were included. Most trials reported minimal differences in marginal bone loss and peri-implant parameters across surfaces. Potential advantages were mainly observed during early healing or in compromised bone. Long-term evidence emphasized the predominance of patient- and site-related risk factors. Microbiological outcomes were scarce and heterogeneous. <b>Conclusions:</b> Implant surface modifications appear to exert a limited and context-dependent influence on peri-implant outcomes. Long-term peri-implant health is primarily driven by multifactorial interactions involving host, microbial, and clinical factors rather than surface characteristics alone.