Chapter 76 - Metallic instruments and implants Flashcards
How may the types of stainless steel used for instruments be classified?
By their microstructure, magnetic attraction, corrosion resistance, and hardness.
What is the microstructure of 400 series stainless steel described as?
Martensitic.
Stainless steel can be classified according to 4 things name them
- Microstratucture
- Magnetic attraction
- Corrosion resistance
- Hardness
What percentage of chromium do martensitic compositions typically contain?
12% to 18%.
term martensitic describes
the type of microstructure
associated with 400 series stainless steel
The 400 series nomenclature refers
to various well-defined alloys, which include compositional trends
related to ________ and ________ content
The 400 series nomenclature refers
to various well-defined alloys, which include compositional trends
related to carbon and chromium content
Name the A, B , C range of carbon for each stainless steel
A, B, or C define an increasing carbon range for a given
alloy (420C > 420B > 420A)
how does the chromium range increase in stainless steel?
chromium range increases
as the three-digit 4XX number increases (440 > 431 > 420).
For the alloy the hardness typically increases or decreases with tempering temperature increases?
For a given alloy, the
hardness typically decreases as the tempering temperature
increases.
Martensitic alloys are very fragile or very hard and resistant?
Martensitic alloys are very hard and resistant to wear,
which makes them ideal for cutting instruments (such as drills,
taps, countersinks, reamers, chisels, and bone-cutting forceps)
and for use in noncutting tools (such as screwdrivers and
wrenches).
Precipitation hardenable (PH) stainless steels contains what?
Precipitation hardenable (PH)
stainless steels contain substantial amounts of chromium, nickel, and copper, plus controlled levels of secondary elements
final hardness is inversely related to the
Various age-hardened techniques (e.g., H900 and H950) are used,
and the final hardness is** inversely** related to the age-hardening
temperature
Precipitation hardenable (PH) instruments are used for what?
non-cutting instruments that require moderate hardness level
Precipitation hardenable (PH) instruments have high or low carbon content
PH has low carbon content
The term austenitic describes the type of microstructure associated
with ___________stainless steel
The term austenitic describes the type of microstructure associated
with 300 series stainless steel
Name two proprietis of austenitic microstructures
has magnetic
excellent corrosion resisten
Name the % of composition in austenitic
The austenitic compositions3
usually contain 16% to 18% chromium and 8% to 10%
nickel.
Name application/instruments using austenitic
drill guides, clamps, hollow sleeves, springs,
and washers.
What does the suffix letter in the nomenclature of martensitic alloys of the 400 series indicate?
The increasing carbon range for a given alloy.
Which heat treatment temperature range is used to harden martensitic alloys?
930°C to 1150°C.
What is a commonly used PH-grade alloy for instruments?
A) 17-4PH.
B) 13-8Mo.
C) 9-12% Nickel.
D) 21-6-9.
A) 17-4PH.
Which microstructure is associated with 300 series stainless steel?
A) Martensitic.
B) Austenitic.
C) Ferritic.
D) Duplex.
B) Austenitic.
What element is added to 316 and 316L austenitic stainless steels to alter its magnetic properties?
A) Molybdenum.
B) Cobalt.
C) Titanium.
D) Vanadium.
A) Molybdenum.
What is Grade 1100 aluminum primarily used for?
A) Cutting instruments.
B) Bone plate or rod templates.
C) High-strength applications.
D) Color-coded instrument systems.
B) Bone plate or rod templates.
What property of aluminum makes it suitable for templates used in medical instruments?
A) High ductility.
B) Magnetic properties.
C) High strength.
D) High carbon content.
A) High ductility.
What does the H32 designation in aluminum alloy 5052-H32 indicate?
A) The percentage of pure aluminum content.
B) The temper of the alloy.
C) The color after anodizing.
D) The heat treatment temperature.
B) The temper of the alloy.
For what type of medical instruments are aluminum alloys commonly used?
A) Depth gages and IM nail-insertion instruments.B) Scalpels and cutting blades.
C) Needles and syringes.
D) Stethoscopes and thermometers.
A) Depth gages and IM nail-insertion instruments.
What is the purpose of anodizing aluminum instruments?
To improve corrosion resistance and surface hardness.
What are titanium alloys used for in the context of noncutting instrument applications?
For their high strength and low weight.
For their anodizing ability.
What property of cobalt-base alloys makes them beneficial for small-diameter guidewires?
High modulus of elasticity.
Aluminum alloys are nonmagnetic and lightweight?
yes nonmagnetic and lighweight and submitted to anodizing tx to resist corrosion
explain the anodizing process
an electrolytical passivation process that increases the thickness of the aluminum oxide surface layer to increase resistance to corrosion for aluminum, consists of detergent cleaning, rinsing, electrolytic anodizing, dyeing (optional), rinsing, and sealing
Galling refers to
Galling refers to the adhesive wear that occurs when two metals rub together at high points on their mating surfaces
Aluminum contact with strong _________(alkaline/acidic) cleaners must be avoided to prevent aggressive chemical attack.
Aluminum contact with strong alkaline cleaners must be avoided to prevent aggressive chemical attack.
What kind of stainless steel is commonly used in orthopedic implants?
A) Wrought 18% chromium-14% nickel-2.5% molybdenum alloy.
B) Carbon steel.
C) Martensitic stainless steel.
D) Alloy steel.
A) Wrought 18% chromium-14% nickel-2.5% molybdenum alloy.
What does the “L” indicate in the implant-quality 316L stainless steel?
A) Large size.
B) Low carbon content.
C) Long-lasting.
D) Low cost.
B) Low carbon content.
Why should stainless steel and titanium implants not be mixed?
A) To avoid color mismatch.
B) To prevent galvanic corrosion.
C) Because of different sterilization methods.
D) To maintain uniform strength.
B) To prevent galvanic corrosion.
What is the maximum carbon content allowed in implant-quality 316L stainless steel?
A) 0.3%
B) 0.03%
C) 0.003%
D) 3%
B) 0.03%
What is the purpose of cold working in stainless steel implants?
A) To increase flexibility.
B) To decrease weight.
C) To increase strength.
D) To enhance magnetic properties.
To increase strength.
What is the primary reason for the excellent corrosion resistance of stainless steel?
A) Nickel content.
B) Presence of a chromium oxide film.
C) High carbon content.
D) Molybdenum addition.
B) Presence of a chromium oxide film.
What does chemical passivation in nitric acid do for stainless steel implants?
A) Changes their color.
B) Alters their dimensions.
C) Removes surface contaminants.
D) Increases their weight.
C) Removes surface contaminants.
What is electropolishing?
A) A process to increase the strength of the implant.
B) A surface treatment that improves corrosion resistance and creates a passivated surface.
C) A technique to sterilize the implants.
D) A method to change the implant’s color.
B) A surface treatment that improves corrosion resistance and creates a passivated surfac
How does shot peening affect implant surfaces?A) Decreases resistance to stress.
B) Reduces surface roughness.
C) Increases residual compressive stress.
D) Enhances magnetic properties.
C) Increases residual compressive stress.
Why is implant-quality stainless steel nonmagnetic?
A) Because of the high nickel content.
B) Due to its single-phase austenitic microstructure.
C) As a result of the electropolishing process.
D) Because of the absence of carbo
B) Due to its single-phase austenitic microstructure.
What is a potential consequence of the 15% nickel content in stainless steel?
A) Decreased strength.
B) Induction of metal sensitivity reactions.
C) Enhanced flexibility.
D) Improved ductility
B) Induction of metal sensitivity reactions.
What phase in the stainless steel microstructure is undesirable for MR scanning considerations?
A) Austenitic phase.
B) Delta ferrite phase.
C) Sigma phase.
D) Chi phase.
B) Delta ferrite phase.
What is commercially pure titanium also known as?
A) Unalloyed titanium.
B) Alloyed titanium.
C) Industrial titanium.
D) Medical-grade titanium.
A) Unalloyed titanium.
How many grades of commercially pure titanium are there according to ISO and ASTM standards?
A) Three.
B) Four.
C) Five.
D) Six.
C) Five.
What does the term ‘extra-low interstitial’ (ELI) indicate about a titanium grade?
A) High content of additives.
B) Low content of nitrogen, carbon, iron, and oxygen.
C) High tensile strength.
D) Low corrosion resistance.
B) Low content of nitrogen, carbon, iron, and oxygen.
As the grade number of commercially pure titanium increases, what happens to its strength and ductility?
A) Strength decreases, and ductility increases.
B) Both strength and ductility decrease.
C) Strength increases, and ductility decreases.
D) Both strength and ductility increase.
C) Strength increases, and ductility decreases.
What is the primary advantage of commercially pure titanium over stainless steel in terms of biocompatibility?
A) Higher strength.
B) Better electrical conductivity.
C) Contains less than 0.05% nickel.
D) More cost-effective.
C) Contains less than 0.05% nickel.
For which patients are unalloyed titanium implants specifically recommended?
A) Those with a history of metal sensitivity.
B) Patients who prefer lighter implants.
C) Patients requiring high tensile strength implants.
D) Patients with a preference for non-colored implants.
A) Those with a history of metal sensitivity.
What unique property does titanium exhibit that contributes to its biocompatibility?
A) Soft tissue and bone adhesion to the implant surface.
B) Flexibility similar to natural bone.
C) Transparency to X-rays.
D) Ability to dissolve in the body over time.
A) Soft tissue and bone adhesion to the implant surface.
What is a major disadvantage associated with titanium implants?
A) High cost compared to other materials.
B) Difficulty in implant removal due to osseointegration.
C) Lack of color options for implants.
D) Reduced tensile strength.
B) Difficulty in implant removal due to osseointegration.
How does the modulus of elasticity of titanium compare to that of stainless steel?
A) It is about the same.
B) It is about 55% of stainless steel.
C) It is higher than stainless steel.
D) It is twice as high as stainless steel.
B) It is about 55% of stainless steel.
Why is a lower modulus of elasticity desirable for titanium implants?
A) It increases stress transfer to the bone.
B) It allows for greater flexibility of the implant.
C) It reduces the weight of the implant.
D) It enhances the visual appearance of the implant.
A) It increases stress transfer to the bone.
What process can be used to increase the strength of commercially pure titanium?
A) Cold working.
B) Heat treatment.
C) Chemical coating.
D) Plastic deformation.
A) Cold working.
What surface finish may be applied to titanium implants to enhance their properties?
Special anodized surface finish
How is the anodizing treatment for titanium different from that used for aluminum?
It applies a known electrical voltage in a chemical solution.
What creates the distinct color seen on anodized titanium?
Visible light diffraction within the oxide film.
How does the density of titanium compare to that of stainless steel?
It is 57% of the density of stainless steel.
What are the two compositions of titanium-6 aluminum-4 vanadium alloys known as?
Ti-6Al-4V and Ti-6Al-4V ELI.
What does the ELI designation denote for titanium alloys?
Extra-low interstitial content.
Which titanium alloy is widely used as an implant material and contains 6% aluminum and 7% niobium?
A) Ti-6Al-7Nb.
B) Ti-6Al-4V.
C) Ti-6Al-4V ELI.
D) CP Titanium.
A) Ti-6Al-7Nb.
Compared to commercially pure titanium, how do titanium alloys generally differ in tensile strength and ductility?
Higher tensile strength and lower ductility.
What are the major alloying elements in the cobalt-base alloy Co-28Cr-6Mo?
Cobalt, chromium, and molybdenum.
What is notch sensitivity and which implant material is known to have better notch-sensitivity resistance?
The effect of stress raisers on mechanical properties; stainless steel.
How may titanium alloys be finished to enhance their properties?
Color anodizing.
What property of cobalt-base alloys makes them suitable for small-diameter guidewires and aiming instruments?
High modulus of elasticity.
What does retrieval analysis of human hip joint prostheses suggest about the biocompatibility of Ti-6Al-7Nb alloy?
It is extremely biocompatible.
What is the major difference in the anodized film between CP titanium and titanium alloys?
The titanium alloy film is composed of a mixture of stable oxides.
How does the wear resistance of cobalt-base alloys compare to stainless steel?
A) It is inferior to stainless steel.
B) It is superior to stainless steel.
C) It is equal to stainless steel.
D) It is not comparable as they serve different functions.
B) It is superior to stainless steel.
What metal-sensitizing agents are present in cobalt-base alloys?
A) Nickel and aluminum.
B) Chromium and cobalt.
C) Vanadium and niobium.
D) Titanium and molybdenum.
B) Chromium and cobalt.
What oxide mixture composes the anodized film on titanium alloys?
A) TiO2 only.
B) Al2O3 only.
C) TiO2 + Al2O3 + Nb2O5.
D) CoO + Cr2O3
Which β-titanium alloy has improved notch-sensitivity properties compared with stainless steel?
A) Ti-6Al-4V.
B) Ti-6Al-7Nb.
C) Ti-15Mo.
D) Co-28Cr-6Mo
C) Ti-15Mo.
What is fatigue in the context of metallic implant materials?
A) The point at which a material breaks under extreme stress.
B) The phenomenon leading to fracture under repeated or fluctuating stresses.
C) The maximum stress a material can endure before breaking.
D) The resistance of a material to wear and tear.
B) The phenomenon leading to fracture under repeated or fluctuating stresses
What is the endurance limit in fatigue testing?
A) The point at which a material fails under a single load cycle.
B) The maximum stress that causes an immediate fracture.
C) The maximum stress below which a material can endure an infinite number of stress cycles.
D) The stress level at which a material becomes notch-sensitive.
C) The maximum stress below which a material can endure an infinite number of stress cycles.
What factors can influence fatigue test results?A) Grain size and processing history.
B) Color and surface finish.
C) Length and thickness of the material.
D) Elasticity and hardness of the material.
A) Grain size and processing history.
How are fatigue properties of materials commonly expressed?
A) In the form of color-coded charts.
B) Through tensile strength measurements.
C) Using the S-N curve.
D) By measuring the density of the material.
c) Using the S-N curve.
What does the S-N curve represent in fatigue testing?
A) The number of cycles required to achieve runout.
B) The stress at which a material fractures.
C) The surface finish of the material.
D) The frequency of fatigue loading.
A) The number of cycles required to achieve runout.
How is bending fatigue testing of bone plates typically conducted?
A) In a tensile testing machine.
B) In a four-point bending fixture.
C) In a compression testing machine.
D) In a high-temperature chamber.
B) In a four-point bending fixture.
What does runout mean in the context of fatigue testing?
A) The point at which the test specimen is removed.
B) The maximum cyclic stress causing immediate fracture.
C) The maximum cyclic stress that does not create fatigue fracture at a certain number of cycles.
D) The point at which the material becomes notch-sensitive.
C) The maximum cyclic stress that does not create fatigue fracture at a certain number of cycles.
Why do titanium alloys exhibit superior fatigue properties compared to CP titanium?
A) Due to their increased ductility.
B) Because of their lower density.
C) Thanks to their higher 0.2% yield strength.
D) As a result of their higher nickel content.
C) Thanks to their higher 0.2% yield strength.
What is the “race between bone healing and fatigue failure” in implant materials?
A) The competition between different implant designs.
B) The process of implant rejection by the body.
C) The balance between the time it takes for bone to heal and the fatigue life of load-sharing implants.
D) The speed at which implants degrade over time.
C) The balance between the time it takes for bone to heal and the fatigue life of load-sharing implants.
What is the primary method for detecting and identifying device failure modes in failure analysis?
A) Light microscopy.
B) Portable x-ray fluorescence analysis.
C) Metallographic examination.
D) Scanning electron microscope (SEM) analysis.
D) Scanning electron microscope (SEM) analysis
