Patient factors related to early implant failures in the edentulous jaw: A large retrospective case-control study.

BACKGROUND: Dental implants provide anchorage for dental prostheses to restore functions for individuals with edentulous jaws. During the healing phase, proper osseointegration is required to prevent early implant failure. More knowledge is needed regarding factors related to early failure of dental implants. PURPOSE: The aim of the present study was to identify possible risk factors for early implant failure, with respect to anamnestic and clinical parameters. MATERIALS AND METHODS: All patients with edentulous jaws with early implant failure (n = 408) from one referral clinic were compared with a matched control group (n = 408) with no implant failure. Early implant failure was identified during the first year of prosthetic function. Matching was performed on age, gender, year of surgery, type of jaw, and type of implant surface. In addition, data on anamnestic and clinical parameters were collected. The data were analyzed with a multivariable logistic regression model using early implant failure as the binary outcome. RESULTS: Five anamnestic factors were statistically significant with respect to higher probability for early implant failure: systemic disease, allergies in general, food allergies, smoking, and intake of analgesic medication. Four clinical conditions (i.e., implants in the opposing jaw, low primary stability, reduced bone volume, and healing complications) were also related to higher probability for early implant failure. CONCLUSIONS: This study identified nine factors associated with early implant failure, several related to patient's general health. Further investigations are needed to fully understand the causality between the obtained variables and early implant failure.

Early Implant Failures in Edentulous Patients: A Multivariable Regression Analysis of 4615 Consecutively Treated Jaws. A Retrospective Study.

PURPOSE: To study the incidence of early implant failures in edentulous jaws and to describe the effects of some patient- and implant-related factors on the risk for early implant failures. MATERIALS AND METHODS: The study retrospectively analyzed 4615 edentulous jaws (4067 patients), consecutively treated with dental implants at one referral clinic from 1986 to 2013. Implant failures that occurred from implant surgery up to the first recall examination 1 year after prosthesis insertion were recorded and defined as early implant failures. All removed implants were included as failures. Features of the study group and early implant failure rates were reported. A multivariable logistic regression model was used for analyzing possible associations between clinical factors, and the risk for early implant failures. Implant surfaces were categorized by means of roughness: turned (Sa 0.5-1.0 µm) and moderately rough (Sa 1.0-2.0 µm). RESULTS: Three hundred twenty-seven patients (344 jaws) were lost to follow-up. Early implant failures occurred in 8.6% of the jaws. In the maxilla there was a significantly higher incidence of early failures compared to the mandible both with turned implants, OR 5.93 (95% CI 4.21; 8.36), and moderately rough implants, OR 2.52 (95% CI 1.19; 5.34). The impact of implant surface roughness was significant in the maxilla with higher incidence of early failures with turned implants, OR 3.51 (95% CI 2.27; 5.42). There was a significant interaction between implant surface and jaw type on early failures (p = 0.034). Older age was associated with lower risk for early implant failures, OR 0.9 (95%CI 0.82; 0.99). In total, 63% of the jaws with failure could proceed with the prosthetic treatment without further implant insertions. Twenty-six percent of the early failures occurred after prosthesis insertion and 59% of those could maintain the same prosthesis after implant loss with or without adjustments. CONCLUSIONS: Changing the implant surface from turned to moderately rough decreased the incidence of early implant failures significantly in the maxilla, but not in the mandible. Older age at implant insertion was associated with lower risk for early implant failures in edentulous patients.