Re-osseointegration of titanium after experimental implant loosening

This study addresses the critical clinical challenge of implant failures due to mechanical overload by developing a novel rat model to investigate re-osseointegration. Metal implants, essential in dental, maxillofacial, and orthopaedic treatments, rely on osseointegration for stability. However, the fate of mechanically overloaded implants remains poorly understood. We introduced intentional traumatic loosening of submicron-modified titanium implants (treated with NaOH) through snap rotational overload in rat tibiae. After four weeks of initial healing, implants were disrupted and then allowed to re-heal for another four weeks. Evaluations using removal torque, histology, histochemistry, and Raman spectroscopy demonstrated successful re-healing with regained mechanical stability, bone-implant contact, and bone volume. Dynamic histology revealed bone tissue remodelling near the implant interface, indicating fractures due to mechanical disruption. These findings confirm that osseointegrated implants can re-heal under normal conditions. The validated rat model offers a controlled platform for future studies on re-osseointegration following traumatic mechanical overload. The potential applications of this experimental model may extend to investigating compromised healing conditions, early/direct loading conditions, and the cellular and molecular mechanisms involved in peri-implant bone repair.