Biomaterials Flashcards
Biomaterials
-restoring function and facilatating healing for people after injury or disease
-may be natural or synthetic, must be BIOCOMPATIBLE
Biocompatability
-the ability of a material to perform with an appropriate host response in a specific application
Advantages of metals
Most commonly usef
- strong, resist fracture high mechanical strength
-easily formed into complex structures (deformable)
Disadvantages of metals
-susceptibility to corrosion
-stress sheilding
-wear debris
Different kinds of metals
-iron-base alloys(stainless-steel)
-cobalt-base alloys
-titanium base alloys
Material selection criteria of metals
-mechanical loading requirements
-chemical + structural properties of the material
Advantages of glass and ceramics
-Very biocompatible with bone
-Low wear rates, resist to microbial attacks
-very stiff and high melting poin t
Disadvantages of glass and ceramics
-brittle
-potential to fail catastrophically
-difficult to construct
-ceramics cannot be reshaped
Bioactive ceramics
-certain compositions of glass and ceramics that stimulate bonding
-important in securing orthopedic medical devices (such as replacement hips, knees and spinal fusion)
Bone grafts
Made of synthetic material
-work by stimulating the body to form natural bone
Spinal fusion
Join together 2 bones(vertebrae) in the spine to stop movement between them
Polymers
-a large molecule composed of repeating structural units (monomers)
-they resemble natural materials
-their chemical bonding + structire can be modified to have flexible, rigid, low strength or high strength materials
-can be permanent or biodegradable
Natural polymeric materials
wool,silk, and natural rubber
Synthetic polymers
nylon, PVC, polystrene, polyethylene, polypropylene, silicone
Advantages of natural materials
-more biocompatible then synthetic
-can recognize and process whats around them
Disadvantages of natural materials
lot to lot variability
-structural complexity
-inadequate biomechanical properties
Composites
Made by mixing 2 components, molding, compacting, or chemically reacting them together
Fiberglass or Carbonfiber
Vascular grafting
-the use of tansplanted or prosthetic blood vessels in surgical procedures
-surgical bypass treats narrowed arteries by creating a detour around the blocked section
-always blood to flow through a new pathwsy
Coronary artery bypass graft
issued for people with occluded coronary arteries (can be more than 1 graft required)
Atherosclerosis
-Thickening of arterial wall, formation of plaque
-Leads to loss of suffiecient blood to the myocardium which can be a heart attack
Vascular Stents
-Used to provide support for a blood vessel
- Placed by inflating a ballor within the narrowed blood vessel then deflating it to place the stent
Complications of Vascular stents
vascular injury or regrowth of scar tissue around the stent which renarrows the blood vessel
-Drug can be used to prevent blockage
