Implant prosthetic emergence angle and its association with peri-implant health and disease

Dental implants can be affected by peri-implant mucositis and peri-implantitis. Plaque control and appropriate prosthetic design may help maintain peri-implant health. Excessively large emergence angles (EA) may increase the association with peri-implantitis, depending on the implant crown angle. This study examined how the implant EA associates with peri-implant health, disease, and tissue. The study was conducted in the Faculty of Dentistry, Division of Periodontology, Bolu Abant İzzet Baysal University. Eighty-eight patients aged 18–70 years (213 dental implants) with high-quality panoramic radiographs. Patients with implants that had been in function with their definitive prosthetic restorations between 1 and 5 years were included in the study. According to the 2017 AAP/EFP World Workshop on Classification of Periodontal and Peri-implant Diseases and Conditions, individuals’ peri-implant condition was assessed using several indices and radiographs. Gingival thickness (GT), gingival phenotype (GP), keratinized gingival width, and EA were also measured. Clustered Generalized Estimating Equations (GEE) models were employed to account for patient-level data dependency, yielding odds ratios and 95% confidence intervals ( p < 0.05). A significant difference in EA was observed between peri-implantitis, peri-implant health, and peri-implant mucositis ( p = 0.001). The peri-implantitis group had the greatest EA. Wide EAs (EA > 30°) were independently associated with greater probing depth, clinical attachment level, gingival index, and a borderline increase in BOP percentage. In conclusion, EA was the only independent factor associated with peri-implantitis after adjustment for peri-implant soft tissue characteristics and plaque accumulation. Patients whose implants have an EA above 30° are significantly more associated with peri-implantitis. Additional studies are needed to further elucidate the relationship between EA and peri-implant tissue condition.