Immediate vs. Delayed Implant Placement Following Alveolar Ridge Procedures with Xeno-Hybrid Bovine Bone Graft: A Retrospective Cohort with Operator-Level Comparison.

Background: In everyday practice, we observed an increased number of complications with a xeno-hybrid bovine graft in challenging cases, prompting a systematic review of timing strategies and the impact of the operator. Objective: To compare early safety and rehabilitation timelines for immediate versus delayed implant placement after alveolar ridge procedures with a xeno-hybrid bovine graft, and to examine operator-level effects. Materials and Methods: Single center retrospective cohort (Danube Private University, Krems, Austria; January 2021-October 2023). Consecutive patients undergoing alveolar ridge preservation (ARP) or reconstruction (ARR; conservative protocol without meshes or rigid frameworks) with a xeno-hybrid bovine graft and subsequent implant were included. Strata: ARP, ARR, ARP with immediate implant placement (ARP+II), ARR with immediate implant placement (ARR+II). Primary endpoint: early implant loss < 12 months after the index surgery. Secondary endpoints: days to implant exposure and days to definitive prosthesis. Results: We analyzed 158 coded interventions (ARP 33; ARR 16; ARP+II 32; ARR+II 77). Early implant loss was uncommon (7/158; 4.4%) and occurred only with immediate implant placement (ARP+II 6.3%; ARR+II 6.5%); no early failures occurred in delayed strata. Immediate implant placement accelerated rehabilitation (exposure: 358/364 vs. 144/162 days; prosthesis: 406/419 vs. 196/204 days; both p < 0.0001). After adjustment for treatment base, timing, and age, no independent operator level effect on early loss was detected. Conclusions: In this university cohort using a xeno-hybrid bovine graft, early implant loss was rare and confined to immediate implant placement, which nonetheless shortened the pathway to exposure and restoration by ~5-7 months. Differences across providers were explained by case selection and protocol choice after adjustment. Clinical Significance: With appropriate case selection and surgical execution, immediate implant placement after ARP/ARR can reduce treatment time by ~5-7 months without a clear increase in early failure within the limits of this cohort; treatment protocol and case triage are the main levers of early outcome.