Purpose: The aim of this study was to determine predictors of implant treatment failure after alveolar ridge preservation (ARP). Methods: The study included patients who received implant treatment after ARP between 2014 and 2020. The demographic, clinical, and radiographic data of these patients were collected. Implant success was defined as the absence of pain or tenderness, no mobility, a change of <2 mm in marginal bone level, and no exudation. A Cox proportional hazards model with shared frailty was used to estimate hazard ratios (HRs) for the demographic, clinical, and radiographic factors contributing to implant failure. Results: The study included 528 implants from 412 patients. The cumulative success rate over 3.5±1.8 years (mean ± standard deviation) was 89.0% (95% confidence interval [CI], 85.4%–92.8%), with 43 failed implants. The multiple Cox proportional hazards model with shared frailty indicated that a pristine bone engagement (PBE) of <1.1 mm was significantly associated with implant failure (HR, 2.50; 95% CI, 1.34–4.67; P=0.004). Conclusions PBE of at least 1.1 mm appears to decrease the probability of implant failure after ARP.