The Influence of Systemic Factors on Postoperative Complications and Osseointegration of Zygomatic Implants: A Retrospective Study with up to 5-year Follow-Up.

This study aimed to retrospectively evaluate the influence of systemic factors on postoperative complications and osseointegration of zygomatic implants over a follow-up of up to 12 years, and to investigate whether implant surface characteristics affect the incidence of complications. This retrospective study reviewed clinical records of patients who received zygomatic implants at a private clinic between 2009 and 2021. Eligible cases included those with complete records and adequate follow-up, while incomplete or interrupted treatments were excluded. All patients were treated using the zygoma anatomy guided approach (ZAGA) after computed tomography planning, with implant types classified into three surface groups: (1) full-body threaded machined, (2) full-body threaded treated, and (3) polished body with apical and cervical threads treated. Patients were followed up at 6 months, 1-4 years, and 5 years or more. The primary outcome was the presence of systemic conditions and postoperative complications (implant loss, oroantral communication, sinusitis, cysts, and infections). Secondary outcomes included the association between implant surface type, number of implants (two or four), and complication rates. Descriptive statistics, Fisher's exact test, and Pearson's test were used, with significance set at p < 0.05. Among 1,026 patients who underwent dental implant surgery, 241 received zygomatic implants, with 195 included in the final analysis after follow-up review. The overall success and survival rates were 95.38% and 95.90%, respectively. Most patients (91.3%) experienced no complications, while 8.7% reported adverse events, primarily implant loss, oroantral communication, sinusitis, or cyst formation. Statistical analysis showed no significant association between systemic conditions, implant macrogeometry, or number of implants (two vs. four) and the occurrence of complications (p > 0.45). Complications were more frequently observed in the medium-term follow-up (12-48 months). These findings suggest that zygomatic implants demonstrate high survival and success rates regardless of systemic status, implant design, or implant number, although complications may arise predominantly in the medium-term period. Although patients with systemic conditions exhibited a higher incidence of complications, these differences were not statistically significant. Therefore, systemic conditions did not increase the risk of postoperative complications or implant loss in this sample.