Emergence Angle, Marginal Bone Loss, and Radiographic Corticalization Around MIS Implants: A 5-Year Retrospective Study of Single, Splinted, and Bridge Restorations

Background/Objectives: Dental implants are a predictable treatment modality for missing teeth, and the crown emergence angle may affect peri-implant tissue health. This study evaluated the influence of crown emergence angle on marginal bone loss (MBL) and the corticalization index (CI) at 3-month and 5-year follow-ups, considering restoration type and implant location. Methods: Records from 155 patients treated with MIS implants were analyzed retrospectively. The primary outcome was marginal bone loss (MBL) at 60 months after loading; secondary/exploratory outcomes included MBL at 3 months and the Corticalization Index (CI) at 3 and 60 months. Three prosthodontic restorations were included: single crowns, splinted crowns, and bridges. Intraoral radiographs were used to measure crown emergence angle, MBL, and CI. Results: Recorded emergence profile was 32° ± 10°. Marginal bone loss increased over time but did not differ significantly among restoration groups. No significant relationship was found between emergence angle and MBL for single crowns (p = 0.369) or splinted crowns (p = 0.176). For bridges, a weak but statistically significant relationship was observed (p = 0.042). CI increased over time in all groups, without significant differences by restoration type. Restoration type was significantly associated with anterior/posterior implant location (p = 0.0004): single crowns predominated anteriorly, whereas splinted crowns and bridges were more frequent posteriorly. No significant association was found for maxilla versus mandible (p = 0.077). Conclusions: Within the limitations of this retrospective radiographic analysis, no clinically meaningful association was observed between emergence angle and MBL for single or splinted crowns. For bridges, the observed association was statistically significant but weak and should be interpreted cautiously. Other biological, biomechanical, and systemic factors may play a greater role in peri-implant tissue stability than emergence angle alone.