Background: Nanotechnological surface modifications on titanium implants aim to optimize bone-tissue interaction, accelerate osseointegration, and prevent the release of toxic wear debris. This study evaluated the tissue response and biomechanical stability of advanced carbon- and metal-oxide-based nanocoatings in an in vivo model.

Methods: Grade IV titanium implants were evaluated under four conditions using a split-body design in the distal femurs of 12 adult male New Zealand white rabbits: uncoated (control), coated with Graphene Diamond-like Carbon (DLC), Niobium via Chemical Vapor Deposition (CVD), and Niobium via Sol-Gel technique. Follow-up periods were set at 30 and 60 days. Analysis included a Reverse Torque Test (RTQ) for biomechanical stability and histopathological evaluation (H&E and Picrosirius Red under polarized light) to assess bone organization, osteoclastic proliferation, collagen matrix maturation, and coating delamination.

Results: RTQ values significantly increased from 30 to 60 days across all groups (p < 0.05), with Graphene-DLC and uncoated titanium achieving the highest biomechanical anchorage. Graphene-DLC maintained excellent interfacial stability, accelerated bone mineralization (low osteoid volumes), and promoted intensive, physiologically normal bone coupling and lamellar remodeling at 60 days. Conversely, Niobium-CVD and Niobium-Gel coatings exhibited severe late-stage delamination, which released particulate debris, triggered chronic foreign body reactions, increased osteoclastic bone resorption, and compromised biomechanical interlocking.

Conclusions: Graphene-DLC coatings successfully preserve structural integrity and effectively enhance functional osseointegration, matching or exceeding the biomechanical performance of conventional titanium. However, interface optimization is mandatory for Niobium-based coatings to prevent mechanical failure and debris-induced osteolysis.

Keywords: Osseointegration; Titanium; Graphene; Niobium Compounds; Rabbits.

Marco Antonio Schueda is an Orthopedist and Traumatologist specializing in knee surgery and arthroscopy, with a Research Fellowship at the Orthopedic Specialty Clinic in Salt Lake City, Utah, USA, and a Doctorate in Orthopedics and Traumatology from UNIFESP, São Paulo. He has extensive academic involvement as a professor at three medical schools, where he has trained more than 1,100 doctors, and currently serves as Coordinator of the Medical School at Universidade do Contestado (UNC). In addition, he is an instructor in medical residency in orthopedics and head of the specialization in knee surgery, having trained 191 orthopedists and knee surgeons. Dr. Schueda has contributed significantly to scientific literature, publishing 56 articles, 32 book chapters, and authoring five books on anatomy, orthopedics, and traumatology. He is an active member of several professional societies, including the Brazilian Society of Knee Surgery (SBCJ), the Brazilian Society of Arthroscopy and Sports Traumatology (SBRATE), the Sociedad Latinamericana de Artroscopía, Rodilla y Deporte (SLARD), and the International Society of Arthroscopy, Knee Surgery and Orthopedic Sports Medicine (ISAKOS).