Corrosion of Surgical Implants University of Technology Materials Eng. Department Biomaterials And Biomedical Engineering Corrosion of Surgical Implants

Biological Environment Corrosion is one of the major processes that cause problems when metals and alloys are used as implants in the body. Corrosion is the interaction between material and its environment Biological Environment

Tissue–implant corrosion The interactions between the material and the tissues are of prime importance. Such interactions induce corrosion/ionization of the implanted device. Corrosion can have two effects. First the implant may weaken and the premature failure will result. The second effect is the tissue reaction leading to the release of corrosion products from the implant. Cells adhering to the surface of a metallic biomaterial M → Mn+ + ne O2 + 4e + 2H2O → 4OHˉ Influences of the presence of fibroblasts on the corrosion of metallic biomaterials

Generalized fibrous capsule forming in response to intramuscularly implanted metal. The metal dissolves in body over time rendering removal surgery

Capsule formation around a polydimethylsiloxane implant. Cells in the periprosthesis tissues in the ankle. Counterstained with hematoxylin. (A): Macrophages (arrowheads) facing necrotic masses (N). (B): Heavy macrophage infiltration in the implant capsule. (C): bone debris (B) surrounded with macrophages. (D): multinuclear foreign body giant cells (empty arrows) in the implant capsule

Peri-implant tissue and immune cell reacting of implant debris

Diagram of the percentage of the uncorroded implant at various time  Infrared microscope spectra of tissue with (red line) and without (blue line) corrosion products. The absorption bands, which are caused by the corrosion products, are marked with arrows. Diagram of the percentage of the uncorroded implant at various time Potentiodynamic polarization

Material: 304 SS, Cobalt based alloy Implant location: Orthopedic/ Dental alloy Material: 316 L stainless steel Implant location: Bone plates and screws Material: 316 SS, CoCrNiFe Implant location: Bone cement Material: 304SS/316SS, CoCr +Ti6Al4V, 316SS/Ti6Al4V Or CoCrMo Implant location: Oral implants, Screws and nuts Material: Ti6Al4V, CoCr, SS Implant location: Ball Joints

Corrosion of stent in bare metal. Corrosion Various Implants Cardiovascular Implants Artificial heart. Corroded stents Corrosion of stent in bare metal.

Corrosion protection Surface modification There is a number of methods, which treat the surface of a metal or alloy to provide protection against corrosion like: Biomimetic Processing. Electrophoretic Deposition (EPD). Glow discharge nitriding. Ion implantation. Thermal spraying. PVD treatments. Laser treatment.

Ion implantation

Hydroxyapatite coatings

Laser nitriding

Hard coatings for orthopaedic implants

Thanks