Bone defects occur due to accidents,
diseases, trauma or abnormal development require a skeletal reconstruction such
as grafts of natural and synthetic materials to replace lost bonor to enhance
new bone formation. Biomaterials are used to make devices to replace a part or
a function of the body in a reliable, safe, physiologically acceptable and
economic manner to improve the quality of life, increasing mobility and reducing
pain. It covers a broad range of materials from metals, ceramics and polymers, to
composites.There are several requirements of metals depend on the specific
implant applications. Stents and stent grafts are implanted to open stenotic blood
vessels; therefore, they require plasticity for expansion and rigidity for
maintaining dilatation. In orthopaedic implant applications, metals are required
to have excellent toughness, elasticity, rigidity,strength and resistance to
fracture. Additionally, for total joint replacement metals are needed to be
wear resistance to avoid debris formation from friction. Dental restoration requires
strong and rigid metals and even the shape memory effect for better results.
Orthopedic implants are the medical
devices manufactured to support a damaged bone or to replace a missing joint or
bone. These orthopedic implants are mainly fabricated using metallic alloys
such as stainless steel, cobalt-chromium and titanium alloys (as a permanent
implants) for their superior mechanical properties (hardness, stiffness, etc.),
and lined with plastic to act as artificial cartilage.Used for implants
composed of 18wt% Cr and 8wt% Ni made it more resistant to corrosion and
stronger than steel. The addition of Mo further improves its corrosion resistance,
known as type 316 stainless steel.
These are generally known for their
excellent wear resistance where they have been
in use in dentistry and in making artificial joints. Is featured by its light weight
compared to other alloys. The most known Ti alloys, Ti-6Al-4V, are considered
as having excellent tensile strength and pitting corrosion resistance.In
particular cases, metallic implants are needed only temporary and are expected
to support the healing process and to thereafter degrade. These degradable bio Mg
is biocompatible, vital for metabolic processes, and the alloys show higher
strength. Metallic Implants are used for Two Primary Purposes Used as
prostheses serve to replace a portion of the body and include devices such as
total joint replacements.
The surgical procedure for each
implant involves removal of the damaged joint and an artificial prosthesis
replacement. Osteoarthritis is the primary reason for orthopaedic implants,
which also called degenerative joint disease. Orthopaedic implants are
available for the hip,knee, shoulder and elbow. Internal fixation is an
operation in orthopaedics that involves the surgical implementation of implants
for the purpose of repairing a bone. Though a broken bone, being a living
tissue, has a tendency to heal itself provided the broken bone to withhold in
the correct position. In the cases where broken bones have to be fixed in the correct and appropriate
position, nails, wires, pins, staples and other orthopaedic implants play
important role by holding the broken bone.
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