Which of these are properties of biomedical ceramics:

Hardness & Scratch resistance & Dimensional stability & Mechanical strength

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Heating irradiated polyethylene to its-melt-point for 20 hours creates:

A more crystaline polyethylene

A more amorphous polyethylene

A micture of crystaline and amorphous polyethylene

A more crystaline polyethylene

A more amorphous polyethylene

A micture of crystaline and amorphous polyethylene

Annealing is used to:

Cross-link polyethylene

Eliminate free radicals

Eliminate crystals

Stabilise the dimensions of the bar

Cross-link polyethylene

Eliminate free radicals

Eliminate crystals

Stabilise the dimensions of the bar

Marathon polyethylene is sterilised by:

Gamma irradiation

Gas plasma

Ethylene oxide

Electron beam

Gamma irradiation

Gas plasma

Ethylene oxide

Electron beam

What was acrylic cement first used for?

Dentistry

What is the purpose of bone cement in total joint replacement?

conveniaent gap filler between the bone and prosthesis (and adherence)

Basic ceramics are produced from

Mined raw materials

High purity precursors

Neither of the above

Mined raw materials

High purity precursors

Neither of the above

Advanced ceramics are produced from:

Mined raw materials

High purity precursors

Neither of the above

Mined raw materials

High purity precursors

Neither of the above

Ceramics can be worked by

Pressing

Forging

Rolling

None of these

Pressing

Forging

Rolling

None of these

Alumina ceramics can be toughened by the additional of;

Carbon

Tungsten

Boron

Zirconia

Carbon

Tungsten

Boron

Zirconia

Alumina ceramics can be toughened by the additional of;

Carbon

Tungsten

Boron

Zirconia

Carbon

Tungsten

Boron

Zirconia

What is an antigen?

The immune system reacts to contact with antigens or substances of various types which are foreign to the individual.

What term is used to describe the process of a macrophage ingesting a foreign body?

Phagocytosis

What is an allergic reaction?

excessive immune response to antigens

What is the name given to the blackening of tissues arround an implant that has generated large volumes of wear debris?

Metallosis

Why can the initial stages of osteolysis often be mistaken for local infection?

The production of large amounts of wear debris as a result of abnormal wear.

!?How does osteolysis generally appear on x-ray?

?????????????

How do we generally overcome the problem of patients needing toatal joint replacement who have a known sensitivity to nickel?

Titan Nitrid Implants

not available at DePuy

What is the term given to describe the body's lack of acceptance of an implant?

acepting loosening

Give three types of host response

acceptance
septic loosening
aseptic loosening

What is biomaterial?

Tastatur-Befehle:

= drehen,

= vor-/rückwärts,

= scrollen

materials of a natural or man-made origin that are used to direct, supplement or replace the functions of living tissue

Explain the term biofunctional.

Tastatur-Befehle:

= drehen,

= vor-/rückwärts,

= scrollen

means that the material must perform in a mechanically satisfactory way

What is the primary factor that is related to changes in the mechanical properties of bone?

Tastatur-Befehle:

= drehen,

= vor-/rückwärts,

= scrollen

Changes in the mechanical properties of bone, whilst related to a number of factors, are primarily related to age.

What are the two "phases" of bone?

Tastatur-Befehle:

= drehen,

= vor-/rückwärts,

= scrollen

Biomechanically, bone tissue may be regarded as a two-phases (biphasic) comosite material, with the mineral as one phase and the collagen and ground substance as the other

Which of the following has the lowest elastic modulus?

Glass

Bone

Metal

Tastatur-Befehle:

= drehen,

= vor-/rückwärts,

= scrollen

Glass

Bone

Metal

What is the term used to descibe a material that exhibits different mechanical properties when loaded along different axes?

Tastatur-Befehle:

= drehen,

= vor-/rückwärts,

= scrollen

anisotropy

What is Wolff's law?

Tastatur-Befehle:

= drehen,

= vor-/rückwärts,

= scrollen

"Bones that is not stressed is lost"

Alteration in the internal architecture as well as the external form of bones, occur, as a consequence of primary changes in the shape and stressing of bones

What is osteopenia, and when is it more likely to occour?

Tastatur-Befehle:

= drehen,

= vor-/rückwärts,

= scrollen

Osteopenia =

Too little stress
Too much stress

What is the most important mechanical property of collagen fibres?

Tastatur-Befehle:

= drehen,

= vor-/rückwärts,

= scrollen

The most important mechnical property of collagen fibres is their tensile strength. (Zugfestigkeit)

What are the two primary functions of articular cartilage in diarthrodial joints?

Tastatur-Befehle:

= drehen,

= vor-/rückwärts,

= scrollen

distribute joint loads over a wide area
allow relative movement of the opposing joint surface with minimal friction and wear

Give three reasons why metals are very popular materials for use in a wide variety of orthopeadic application.

have relatively high elastic moduli and reasonable yield points
are ductile (dehnbar) enough
have relatively high fatigue strength

What is the first step in alloy fabrication?

Extraction of metal ores from mineral deposits

Give another name for investment casting

lost wax casting

What is the difference between forging and working?

forging: forming of components

working: pre-processing of alloys before final forming

Name three finishing processes of metals and briefly describe each one

Machining (drehen, fräsen, schleifen)

Forging (schmieden)

Grinding (schleifen)

What are implant grade stainless steels mainly used for in orthopaedics today?

This has been largely abandoned since early casting alloys displayed inadequate yield and fatigue strengths, resulting in unnacceptable incidences of hip stem bending and comonent fatigue fracture