Fatigue performance and failure mechanisms of caliber‑rolled CP‑Ti SLA and SLActive surface modified dental implant

Dental implants are subjected to long‑term cyclic occlusal loading, under which fatigue failure remains a primary reliability concern. This study investigates the influence of microstructural refinement, surface condition, and implant–support boundary conditions on the fatigue performance of commercially pure titanium Grade 2. Caliber‑rolled ultrafine‑grained Grade 2 titanium was fabricated to enhance mechanical resistance and subsequently treated with SLA and SLActive surface modifications. Fatigue behavior was evaluated under ISO 14801‑compliant loading and compared with non‑rolled Grade 2 titanium, and untreated Grade 2 titanium. The results demonstrate that caliber‑rolled Grade 2 titanium with surface modification exhibits approximately twice the fatigue life of untreated Grade 2 titanium, reducing the fatigue performance gap between Grade 2 and Grade 5 to nearly half of its original magnitude. In addition, specimens tested under a tight‑holder condition, representing simulated osseointegration, showed a marked increase in static and fatigue resistance, highlighting the critical role of implant–support interaction in fatigue performance. These findings confirm that fatigue life is governed by a coupled material–surface–system response and demonstrate the effectiveness of microstructural refinement and tailored surface modification in controlling fatigue failure of dental implant systems.