Technology

other coatings

Get informed about coatings for cementless implant fixation.

TCP coating

Tricalcium phosphate coating

 

TCP is a blend of brushite and hydroxyapatite (or HA) – each being forms of calcium phosphate. Both bone regeneration and fracture healing can start over low-calcium phases (such as brushite) and since brushite is readily soluble it is able to act as a reservoir for the calcium and phosphate ions that are required for bone apposition. Plus, because brushite is an early stage of the bone mineral HA, it is very biocompatible.

In granular it can be used to support the natural fracture healing process. When used as a coating it can support the growth of bone onto and/or into an implant. With these properties, the thin (20μm ±10μm), bioactive TCP layer acts as a link between living bone and the implant surfaces coated with it. TCP is resorbed within 6 to 12 weeks via a controlled mechanism and is completely replaced by new bone tissue. Thus the coating remains only until the implant has ingrown and a solid connection between the implant surface and the surrounding bone tissue has been achieved.

 

 

The advantages at a glance:

 

  • a thin layer ensures the complete, controlled resorption and replacement by body's own bone
  • excellent biocompatibility
  • optimum solubility and controlled absorption front
  • complete and uniform coverage of porous surfaces and complex implant geometries
  • large periprosthetic calcium and phosphate ion reservoir providing excellent conditions for the proliferation of osteoblasts
  • faster and improved healing and/or osseointegration

Facts TCP:

 

  • coating is applied electrochemically
  • phase composition ≥70% brushite and ≤30% HA (hydroxylapatite)
  • color: light gray structured
  • layer thickness: 20 ± 10 μm
  • adhesion strength: > 15MPa
  • successful clinical use since 1995

implaFix® HA coating

Hydroxyapatite coating

Hydroxyapatite belongs to a group of chemicals called calcium phosphates and is a natural component of healthy bone. It is an osteoconductive and thus bioactive material which, when used as a prosthetic coating, promotes the growth of bone onto and/or into the HA-coated surfaces of an implant.

The osseointegration process can be enhanced by combining HA with porous coatings such as commercially pure titanium (cpTi).

Facts HA:

 

  • layer thickness: 90μm-155μm (depending on implant design)
  • porosity: 10-30% (depending on implant design)
  • adhesion strength: > 15MPa
  • roughness: 30-50μm (depending on implant design)

implaFix® coating

cpTi commercially pure titanium coating

 

cpTi is applied to implant fixation surfaces to provide rough and porous areas which promote bone growth onto and/or into a device. Thus cpTi is responsible for the mechanical anchoring of the implant to bone.

The porous cpTi layer is applied to an implant via a plasma spraying process: An inert gas (argon) mixture is heated by a high-energy arc and is ionised / converted into a plasma which then is forced through a nozzle-shaped anode at high speed. As this high temperature plasma flame emerges, the cpTi powder particles are added to it and are melted before they are able to collide with the implant substrate surfaces being coated. The high speed collisions between the cpTi particles and the implant produce a layer which is securely fixed.

Facts implaFix®:

 

  • color: grey
  • layer thickness: 100μm-350μm (depending on implant design)
  • roughness: 17-55μm (depending on implant design)
  • porosity: 15% -30% (depending on implant design)
  • adhesion strength: > 22MPa

pc

porous coating

 

This type of coating is made up of cobalt chromium molybdenum alloy (CoCrMo) beads each with a diameter of ~300μm. A layer of these beads is sintered to the implant fixation surfaces. Then a second layer is sintered on top of the first layer before a third and final layer is applied. This results in a porous structure that aids osseointegration.