Biocompatibility
Titanium is biologically inert, meaning the body does not reject it or react against it as a foreign material. The stable oxide film on the surface prevents the release of metal ions into surrounding tissue, avoiding the allergic and inflammatory responses seen with other metals. This tolerance of the human body is the first requirement for any implant material.
Corrosion Resistance in the Body
Body fluids are saline and slightly corrosive, and they attack unprotected metals aggressively. Titanium resists this environment through its self-healing oxide film, which repairs itself if damaged and stays intact for decades inside the body. The metal does not pit, crevice corrode or release corrosion products that could harm adjacent tissue.
Osseointegration
Osseointegration is the direct structural and functional bond between living bone and the implant surface, and titanium is the material that made it possible. Bone cells grow onto and into the roughened titanium surface, anchoring the implant without an intervening soft-tissue layer. This behaviour is the basis of dental implants, joint replacements and fracture fixation.
Mechanical Properties
Titanium has an elastic modulus near 110 GPa, lower than cobalt-chromium and stainless steel, which reduces stress shielding and preserves the surrounding bone. Its fatigue strength suits the repeated loading of joints and spines, and its density of 4.51 g per cubic centimetre keeps implants light. Implant grades are defined by ASTM F67, F136 and ISO 5832 standards.
Imaging Compatibility
Titanium is non-magnetic, so patients with titanium implants can safely undergo MRI examinations, which is not true of some other implant alloys. The metal also produces far less imaging artifact than stainless steel in CT and MRI scans, which helps surgeons evaluate the implant and the healing bone. This compatibility simplifies follow-up care.
Surgical Applications
Hip, knee and shoulder replacement components.
Bone plates, screws and intramedullary nails.
Dental implants and maxillofacial fixation.
Spinal fusion systems and cages.
Cardiovascular devices such as pacemaker cases and heart valve frames.
Frequently Asked Questions
Q: Why is titanium used in surgery?
A: It is biocompatible, corrosion resistant, non-magnetic, fatigue resistant and bonds directly with bone.
Q: What is osseointegration?
A: The direct bond between living bone and the implant surface, which anchors implants without a soft-tissue layer.
Q: Which standards govern implant titanium?
A: ASTM F67 and F136 and the ISO 5832 series define surgical implant titanium materials.
Q: Is titanium safe for MRI?
A: Yes, titanium is non-magnetic and produces little imaging artifact, so it is compatible with MRI.
Q: Why does titanium preserve bone?
A> Its lower elastic modulus reduces stress shielding compared with steel and cobalt-chromium implants.
Q: Where are titanium implants used?
A: In joint replacements, bone plates, dental implants, spinal systems and cardiovascular devices.
