Intro to Biomaterials Flashcards
Nonviable material used in a medical device, intended to interact with biological systems; defined by their application not chemical make-up
biomaterials
Physical requirements of biomaterials
hard and flexible materials
Chemical requirements of biomaterials
- must not react with any tissue in the body
- must be non-toxic to the body
- long-term replacement must not be biodegradable
What do biomaterials have in common?
-must have intimate contact with patient’s tissue or body fluid providing a real physical interface
biomaterial introduced in dentistry in 1937
PMMA - polymethyl methacrylate
biomaterial first used to fabricate an arterial prosthetic in 1958
PETE, a.k.a. Dacron Fabrics - polyethylene terephthalate
In 1960, Charnley uses _______ and _________ for total hip replacement
PMMA and stainless steel
What year was Society of Biomaterials was formed?
1975
High molecular weight molecule made up of a small repeat unit
polymer
low molecular weight compound that can be connected together to give a polymer
monomer
short polymer chain
oligomer
polymer made p of 2 or more monomers
copolymer
3 types of copolymer?
random, alternating and block
What does it mean to have good compatiblity?
Good biocompatibility is achieved when the material exists within a living body without adversely or significantly affecting it or being affected by it.
- material should have adequate mechanical strength, chemical and physical properties
- biomaterials must be compatible with body tissues mechanically, chemically as well pharmacology
Explain the 3 generations of biomaterial
- 1st gen: specified by physicians; accidental rather than by design
- 2nd gen: developed through collabs of physicians and engineers; engineered implants and build on 1st gen exp.
- 3rd gen: bioengineered implants using bioeng. materials
Biomaterial of heart valve
- Fabricated from carbons, metals, elastomers, fabrics and natural valves (pig) and should NOT react w/ chem in body
- attached by polyester mesh
- tissue growth facilitated by polar oxygen-containing groups
- pretreated to reduce immunologic reactivity and enhance durability
Which heart valve is used most widely?
bi-leaflet tilting disk heart valve
Problem with substitute heart valves
degeneration of tissue, mechanical failure, postop infection and induction of blood clot
small titanium fixture that serves as the replacement for the root portion of a missing natural tooth and are capable of osseointegration
dental implant
What material are most dental implants made of?
pure Ti screw-shaped cylinders that act as roots for browns and bridges, or as supports for dentures
phenomenon where a material is capable of bonding to bone
osseointegration
What is the special requirement in the application of dental implants?
it should have the ability to form a tight seal against bacterial invasion where the implant traverses the gingival (gum)
biomaterial of hip joint replacement
Fabricated from specific high-strength metal alloy (corrosion resistant), composites, ultrahigh molecular weight polyethylene and thermoset plastics
biomaterial of intraocular lenses
made of polymer modified masterseal (PMM), silicone elastomer, and other materials used to replaced a natural lens when it becomes cloudy
characteristics of vascular grafts
- must be flexible
- designed w/ open porous structure
- achieve and maintain homeostasis
- porous
- permeable
- good structure retention
- adequate burst strength
- high fatigue resistance
- low thrombogenecity
- good handling properties
- biostable
vascular grafts permeability
- braids: 350-2500 ml cm2/min
- loosely woven knits: 1200-2000 ml cm2/min
- tightly woven knits: 2000-5000 ml cm2/min
weaves: <800 ml cm2/min
characteristics biomaterials science
- multidisciplinary
- many diverse materials
- dev’t. of biomaterials devices
- magnitude of the field
- success and failure
hard tissue replacement materials
metals, ceramics, used in orthopedic and dental materials
soft tissue replacement materials
polymers, cardiovascular and general plastic surgery materials
central issues for biomaterials
1) what represents a good design
2) who should be responsible when devices perform “with an inappropriate host response”
3) what are the cost/risk or cost/benefit ratios for the implant or therapy
subjects integral to biomaterials science
- toxicology
- biocompatibility
- functional tissue structure and pathobiology
- healing
- dependence on specific anatomical site
- mechanical and performance requirements
- industrial involvemen
- ethics
- regulaion
deals with substances that migrate out of biomaterials
toxicology
critical considerations to workers in the functional tissue structure and pathobiology field
- the key principles governing the structure of normal and abnormal cells, tissues and organs
- the techn. by w/c the structure and function of normal and abnormal tissue are studied
- the fundamental mechanisms of disease processes
mechanical and performance requirements
mechanical performance, mechanical durability and physical properties (functional)
