Prosthetic Emergence Angles and Implant Outcomes: A Retrospective Study With at Least 5 Years of Follow-Up

The influence of prosthetic emergence angles on peri-implant tissue stability has become a topic of growing interest. While wide emergence angles have been associated with increased marginal bone loss (MBL) and peri-implantitis, available evidence is limited and largely based on studies using prefabricated abutments. This retrospective study aimed to evaluate the impact of customized implant-supported fixed dental prostheses (iFDPs) emergence angles on peri-implant MBL and peri-implant health after a minimum of 5 years of follow-up.

Patients rehabilitated with single or multiple iFDPs between 2010 and 2019 were retrospectively screened. Inclusion required a minimum follow-up of 5 years. Clinical parameters and radiographic marginal bone loss were assessed. Emergence angles (mesial, distal, buccal, palatal/lingual) were measured and categorized as < 40°, 40°-59°, or ≥ 60°. Multivariable regression models adjusted for smoking and follow-up duration analyzed associations between emergence angles, MBL, and peri-implantitis.

Fifty-two patients with 112 implants met the inclusion criteria. Mean emergence angles were: mesial 43.9°, distal 40.6°, buccal 49.5°, and palatal 45.8°. Overall, peri-implant tissues remained stable, with mean bone loss values ≤ 0.8 mm and mean PPD 1.8-3.9 mm over time. No significant correlation was found between emergence angle categories and MBL.

Prosthetic emergence angle did not significantly influence peri-implant bone loss or peri-implantitis when customized abutments were used. Individualized abutments might mitigate risks associated with wide emergence angles.