Postoperative infections after dental implant placement: Variables associated with increased risk of failure

Background: wound infections after dental implant placement are a rare finding that might lead to early implant failure. However, the available information on this topic is scarce. Methods: this retrospective cohort study was conducted to determine factors that may increase the failure rate of dental implants that presented a postoperative infection during the osseointegration period. Postoperative infections were defined as the presence of pus or fistula in the surgical area, with pain or tenderness, swelling, redness, and heat or fever, before prosthetic loading. A bivariate and multivariate analysis of the data using Cox proportional-hazards regression was performed to detect prognostic factors for implant failure in patients that suffer infections. Results: the patient-based prevalence of postoperative infections after implant placement was 2.80% (95% confidence interval (95%CI): 2.04% to 3.83%). Thirty-three out of 37 (89.19%) patients with infections had to be surgically retreated because of antibiotic failure and 65% of the infected implants were removed. The bivariate analysis showed a significant association between implant failure and the collar surface (HR: 3.12; 95% CI: 1.16 to 8.41; P = 0.014). Cox proportional-hazards regression indicated that rough-surfaced collars increased 2.35 times the likelihood of failure (95% CI: 0.87 to 6.37; P = 0.071). Conclusions: the survival of implants placed in the maxilla, with smooth collar, and late-onset of infection was higher than those placed in the mandible, with a rough collar and early onset of infection. In general, signs of infection after dental implant placement compromises the survival rate of the affected fixtures.