Splinting or Nonsplinting Adjacent Implants? A Retrospective Study Up to 15 Years: Part I—Biologic and Mechanical Complication Analysis

Purpose: To analyze the biologic and mechanical complications of splinted and nonsplinted implant restorations.
Materials and Methods: A total of 423 patients (n = implants: 888) were included in the study. Biologic and mechanical complications that occurred for 15 years were analyzed using the multivariable Cox regression model, and the significant effect of the splinting of prostheses and other risk factors were evaluated.
Results: Biologic complications occurred in 38.7% of implants: 26.4% of nonsplinted implants (NS) and 45.4% of splinted implants (SP). Mechanical complications occurred in 49.2% of implants: 59.3% NS and 43.9% SP. Implants splinted with both mesial and distal adjacent implants (SP-mid) had the highest risk of peri-implant diseases. As the number of implants splinted increased, the risk of mechanical complications decreased. Long crown lengths increased the risk of both biologic and mechanical complications.
Conclusion: Splinted implants had a higher risk of biologic complications and lower risk of mechanical complications. The implant splinted to both adjacent implants (SP-mid) had the highest risk of biologic complications. The greater the number of implants splinted, the lower the risk of mechanical complications. Long crown lengths increased the risk of both biologic and mechanical complications.