Maxillary sinus augmentation as a risk factor for implant failure.

Purpose: The investigators sought to determine whether maxillary sinus augmentation (MSA) was an independent risk factor for implant failure.

Materials And Methods: Using a retrospective cohort study design, the investigators enrolled a sample composed of subjects having 1 or more implants placed in the posterior maxilla. The primary predictor variable was MSA status at the time of implant placement (MSA present or absent). MSA consisted of a lateral window (external) or an osteotome (internal) procedure. The outcome variable was implant failure defined as implant removal. Demographic, health status, anatomic, implant-specific, abutment-specific, prosthetic, and perioperative variables were also examined. Overall implant survival was estimated using Kaplan-Meier analysis. Risk factors for implant failure were identified using Cox proportional hazard regression models.

Results: The sample consisted of 318 patients and 762 posterior maxillary implants. The mean duration of follow-up was 22.50 +/- 19.06 months. The 5-year survival rates for implants in the ungrafted and grafted posterior maxilla were 88.0% and 87.9%, respectively (P = .08). After adjustment for covariates, MSA status was not an independent risk factor for implant failure (P = .9). Tobacco use (P < .001), implants replacing molars (P < .001), and 1-stage implants (P < .001) were statistically associated with an increased risk for implant failure.

Discussion: MSA status was not associated with implant failure risk. This finding may be subject to selection bias, as successful MSA was requisite prior to implant placement.

Conclusion: MSA status was not associated with an increased risk for implant failure. Of the 3 factors associated with an increased risk for failure, tobacco use and implant staging may be modified by the clinician to enhance outcome.