Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Ortho II > Biomechanics > Flashcards

Biomechanics Flashcards

(77 cards)

Start Studying
1
Q

Define mechanics

A

The branch of physics that is concerned with the analysis of the action of forces on matter or material systems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define biomechanics

A
  • Application of mechanical principles on living organisms
  • Includes research and analysis of the mechanics of living organisms and the application of engineering principles to and from biological systems
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Define wire

A

Metallic strand stretched by tensile forces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Active use of orthodontic wires? (2)

A
  • Archwires

- Coils or springs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Passive use of orthodontic wires? (3)

A
  • Retention: adams clasp, ball clasp, arrowhead clasp
  • Stabilization: labial wire spring (labial bow)
  • Ligatures
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is an archwire?

A

Metallic strand shaped according to a diagram that reproduces ideal dental arch
form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is Hooke’s law?

A

The displacement or size of the deformation is directly proportional to the deforming force or load. Under these conditions the object returns to its original shape and size upon removal of the load

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the physical properties described in biomechanics? (6)

A
  • Hooke’s law
  • Springiness
  • Stiffness
  • Resilience
  • Formability
  • Range
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Formula for Hooke’s law?

A

K=stress/strain

K- elastic modulus/young’s modulus
stress = force
strain = deflection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is hooke’s law measured in?

A

Megapascals (MPa)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Formula for force?

A

F=K*Deflection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What happens if force is greater than deflection?

A

stiffness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What happens if deflection is greater than force?

A

Springiness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Define stiffness

A

The extent to which it resists deformation in response to an applied force

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Define springiness (2)

A
  • aka elasticity

- Property of materials which return to their original shape after they are deformed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Define resilience

A

Energy storage capacity of the wire, which is a combination of strength and springiness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Define formability

A

Amount of permanent deformation that a wire can withstand before failing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Define deflection

A

If the wire is deflected beyond its yield strength, it will not return to its original
shape, but clinically useful springback will occur unless the failure point is reached.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Define range

A

Distance that the wire will bend elastically before permanent deformation occurs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Biocompatibility properties of an ideal wire? (3)

A
  • Corrosion resistant
  • Dental plaque
  • Environmental stability
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the types of forces? (3)

A
  • Tensile (traction and compression)
  • Torsion
  • Bending
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How can you classify wires? (3)

A
  • cross-sectional shape
  • size (cross sectional diameter)
  • alloys
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the cross-sectional wire shapes? (5)

A
  • Round
  • Multistrand
  • Square
  • Rectangular
  • Others: Semicircular, oval
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Convert mm to inches

A

multiply by 4 and divide by 100

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Convert inches to mm
multiply by 100 divide by 4
26
What are the types of wire alloys? (4)
- Gold and precious metal - Stainless steel - Cobalt Chromium alloy - Titanium alloys
27
What is the composition of stainless steel alloy wire? (4)
- iron and carbon alloy - 18% chromium - 8% nickel
28
Stainless steel martensitic? (3)
Body centered cubic - stronger and more resistant - instruments
29
Stainless steel austenitic A-300? (5)
Face centered cubic - Springiness (Depends on diameter) - formability - good properties - most used
30
Advantages of stainless steel wires? (6)
* Formability * Reasonable degree of stiffness/springiness * Low cost * Low superficial friction * Can be soldered and welded * Corrosion resistant
31
Disadvantages of stainless steel wires? (4)
* High Young’s modulus * Intense deactivation curve * Nickel release * Difficult clinical management
32
What is the composition of cobalt chromium alloy wires?
- 40% Co - 20% Cr - 15 % Ni - Iron - Mo (Molybdenum)
33
What is another name for cobalt chromium alloy wires?
Elgiloy
34
Cobalt chromium alloy wires are ______ stiff than stainless steel
less
35
Which wire type has the greatest formability?
cobalt chromium alloy wires
36
How many different grades with different properties do cobalt chromium alloy wires have?
4
37
Which cobalt chromium alloy wire can be soldered?
Blue eligiloy
38
How much are cobalt chromium alloy wires used?
little use
39
What are the different generations of titanium alloy wires? (4)
1. Nitinol or M - NiTi 2. Beta Titanium. TMA (Titanium Molybdenum alloy) 3. A – NiTi 4. Copper NiTi
40
What is NiTi composed of?
- 54% titanium | - 44% Nickel
41
What is the structure of NiTi? (3)
Two criystallographic structures • Austenitic. Cubic crystal. Stable. “High temperatures” • Martensitic. Monoclinic crystal,, hexagonal. Unstable. Low temp.
42
Austenitic of Ni Ti?
- Cubic crystal. - Stable. - “High temperatures”
43
Martensitic of Ni Ti?
- Monoclinic crystal - Hexagonal - Unstable - Low temp
44
Phase transitions of NiTi in response to... ? (2)
- reasonable temperature changes - applied force
45
NiTi elasticity? (2)
- Superelasticity | - Thermoelasticity
46
NiTi memory?
Shape
47
NiTi hookes law? (2)
Non-elastic force-defelction curve | don´t obey Hooke’s law
48
What happens when there is a phase transition from austenitic to martensitic? (5)
changes crystal’s structure, volume, shape and | properties WITHOUT atomic strain
49
How do wires change from austenitic to martensitic? (2)
In response to applied forces or cooling
50
How do wires change from martensitic to austenitic?
Martensitic phase is unstable so it returns to austenitic structure with the ideal dental arch form
51
What is shape memory?
Ability of the material to “remember” its original shape after being plastically deformed while in the martensitic form
52
What is superelasticity or pseudoelasticity?
Elastic (reversible) response to an applied stress, caused by a phase transformation between the austenitic and martensitic phases of a crystal (fails Hooke’s law)
53
What is thermoelasticity?
Great “elastic” deflection that reverts in response to temperature changes
54
Look at slide 51/61
and figure out what its for
55
M-NiTi general characteristics? (5)
* Stabilized martensitic form * No phase transition effects * Great shape memory * Much more springiness than stainless steel * No formability
56
TMA general characterisitcs? (4)
- Titanium-molybdenum alloy - Nickel free - Formability-elasticity (More springiness than stainless steel Less formability than stainless steel) - Little use: Springs of some appliances (pendulum)
57
A-NiTi characterisitcs? (4)
* Not stabilized * Phase transition in response to applied force * Superelasticity * Light, continuous, predictable forces
58
Copper NiTi (5)
* Thermoelasticity * Copper allows control of transition temperature. * From austenitic form to martensitic by cooling, without atomic strain. * Rising temperature makes the wire return to austenite and ideal arch form. * Austenite transition temperatures: 27, 35 y 40ºC
59
Deactivtation graphs
slide 56/57
60
Clinical characterisitcs of A-NiTi, Niti-Cu? (5)
* Light, continuous, constant, predictable forces * Easy clinical management * Shorter chair time * More time between appointments * Easy to get out of control. Iatrogenic
61
Formability of the types of titanium wires in order? (5)
* 1º Cr -Co * 2º Acero * 3º TMA * 4º M- NiTi * 5º A-NiTi
62
Springiness of the types of titanium wires in order? (5)
* 1º NiTi - Cu * A-NiTi * 2º M-NiTi * 3ºTMA * 4º Cr -Co * 5º Acero
63
Effects of length and diameter on elastic properties?
The force needed to deflect a wire (stiffness) is directly proportional to the fourth power of diameter and inversely proportional to the third power of length
64
Formula for stiffness?
Stiffness = d^4 or Stiffness = 1/(L^3)
65
Formula for springiness
``` Springiness = 1/(d^4) Springiness = L^3 ```
66
Round wire? (2)
- Initial stages of treatment | - Crown alignment and leveling
67
Multistrand wire? (2)
- Initial stages of treatment | - Crown alignment and leveling
68
Square wire?
Harder to bend because there is more volume
69
Rectangular wire? (5)
- Used in final stages of orthodontic treatment - Causes very small teeth movements - ex. changes in inclination of roots - Torque control - Radicular movements
70
Rounded wire size 0.008-0.012
Ligatures (fragility)
71
Rounded wire size 0.012-0.020
Archs (springiness)
72
Rounded wire size 0.020-0.045
Auxiliary appliances (formability)
73
Rounded wire size 0.045-0.060
Intra/extra oral appliances (stiffness)
74
Multistrand wire size 0.015-0.021
Archs
75
Square wire size 0.016-0.018 x 0.016-0.018
Archs
76
Rectangular wire size 0.016-0.018 x 0.022
Archs - Bracket slot (0.018")
77
Rectangular wire size 0.017-0.022 x 0.025
Archs - Bracket slot (0.018")

Ortho II (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions