CORROSION OF SURGICAL IMPLANTS

University of TechnologyMaterials Eng. Department

Biomaterials And Biomedical Engineering

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

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

Influences of the presence of

fibroblasts on the corrosion

of metallic biomaterials

M → Mn+ + neO2 + 4e + 2H2O → 4OHˉ

M → Mn+ + neO2 + 4e + 2H2O → 4OHˉ

Click icon to add pictureGeneralized fibrous capsule forming in response to

intramuscularly implanted metal.

The metal dissolves in body over time rendering removal

surgery

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

Capsule formation around a polydimethylsiloxane implant.

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.

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: 304SS/316SS, CoCr +Ti6Al4V, 316SS/Ti6Al4V Or CoCrMoImplant location: Oral implants, Screws and nuts

Material: 316 SS, CoCrNiFe Implant location: Bone cement

Material: Ti6Al4V, CoCr, SS Implant location: Ball Joints

Cardiovascular Implants

Corrosion Various Implants

Artificial heart.

Corrosion of stent in bare metal.

Corrodedstents

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