Ortho - Lecture 6: Biology & Biomechanics

Question 1

Center of mass/gravity; point of balance

Answer 1

Free body

Question 2

The center of resistance for a tooth with PDL/bone surrounding it is ____________ of the root length (from CEJ to apex)

Answer 2

1/2 to 1/3

Question 3

Point at which resistance to movement can be concentrated for mathematical analysis

Answer 3

Center of resistance

Question 4

What do the following factors affect the location of?

Alveolar bone height
Size of tooth
Number of roots
Root length
Number of teeth

Answer 4

Center of resistance

Question 5

All rigid body movements are ___________ or ___________, or a combination of the two

Answer 5

rotations; translations

Question 6

Have magnitude, but no direction

Answer 6

Scalars

Question 7

Examples are temp, mass, length, time-algebric addition

Answer 7

Scalars

Question 8

Have magnitude and direction

Answer 8

Vectors

Question 9

Examples are force, velocity, electric intensity field, acceleration

Answer 9

Vectors

Question 10

T/F: A load applied to an object will tend to move it in the direction of the applied force

Answer 10

True

Question 11

How is force measured in ortho?

Answer 11

Grams or ounces

Question 12

Tendency of a force to rotate an object about an axis

Answer 12

Moment

Question 13

2 equal and opposite forces whose lines of action do not coincide

Answer 13

Couple

Question 14

Force through CR = ?

Answer 14

Translation

Question 15

Force NOT through CR = ?

Answer 15

Translation + Rotation

Question 16

Pure rotation around CR = ?

Answer 16

Couple

Question 17

Mf means what

Answer 17

Moment caused by force

Question 18

Mc means what

Answer 18

Moment caused by couple

Question 19

Force equation

Answer 19

Mf = F x d

Question 20

Ortho force NOT through CR causes…

Answer 20

Mf

Question 21

Bracket/wire interface causes…

Answer 21

Mc (in opposite direction)

Question 22

The point around which rotation occurs when an object is being moved; will vary depending on force/moment/couple being applied

Answer 22

Center of rotation

Question 23

Connect the before and after positions of 2 points, it is the intersection of the perpendicular bisectors of the lines

Answer 23

Center of rotation

Question 24

What is the bone-forming organ?

Answer 24

PDL

Question 25

Which part of PDL? Function = ligament attachment, resist movement

Answer 25

Collagenous fibers

Question 26

Which part of PDL? Function = build and remodel collagen

Answer 26

Cellular elements

Question 27

Which part of PDL? Function =

Answer 27

Tissue fluid

Question 28

How many seconds of force cause the following to occur to the PDL? Fluid incompressible, bone bends, piezoelectric signal

Answer 28

1 sec

Question 29

How many seconds of force cause the following to occur to the PDL? Fluid is expressed, tooth moves in PDL space

Answer 29

1-2 seconds

Question 30

How many seconds of force cause the following to occur to the PDL? Fluid is squeezed out, tissues compressed, pain if heavy pressure

Answer 30

3-5 seconds

Question 31

What are the 3 parts of biological control of tooth movement?

Answer 31

Altered blood flow/strain Chemical messengers Cell activation

Question 32

How much time of light force causes the following to occur to the PDL? Blood flow altered, oxygen tension changes, prostaglandins/cytokines released

Answer 32

Minutes

Question 33

How much time of light force causes the following to occur to the PDL? Metabolic changes, chemical messengers affect cellular activity, enzyme levels change

Answer 33

Hours

Question 34

How much time of light force causes the following to occur to the PDL? Increased cAMP levels, PDL cell differentiation

Answer 34

~4 hours

Question 35

How much time of light force causes the following to occur to the PDL? Tooth movement begins as osteoclasts/blasts remodel bony socket

Answer 35

~2 days

Question 36

How much time of heavy force causes the following to occur to the PDL? Blood flow cut off to compressed PDL area

Answer 36

Minutes

Question 37

How much time of heavy force causes the following to occur to the PDL? Cell death in compressed area

Answer 37

Hours

Question 38

How much time of heavy force causes the following to occur to the PDL? Cell differentiation in adjacent marrow spaces, undermining resorption begins

Answer 38

3-5 days

Question 39

How much time of heavy force causes the following to occur to the PDL? Undermining resorption removes lamina dura adjacent to PDL, tooth movement occurs

Answer 39

7-14 days

Question 40

What type of force causes the following? What is the resulting resorption? Blood flow altered, but not stopped Cell differentiation in PDL

Answer 40

Light force -> frontal resorption

Question 41

What type of force causes the following? What is the resulting resorption? Cell death in PDL Must rely on bone marrow

Answer 41

Heavy force -> undermining resorption

Question 42

What are the adverse biological effects of ortho force and tooth movement?

Answer 42

Pain Root resorption Bone loss Mobility Pulp

Question 43

Pain is caused by inflammation at the _________ and ischemic areas in the _______

Answer 43

apex; PDL

Question 44

Heavy or light force? Pain develops immediately; PDL is crushed

Answer 44

Heavy

Question 45

Heavy or light force? Pt feels little or nothing immediately

Answer 45

Light

Question 46

When is pain going to be the worst?

Answer 46

Initial activation

Question 47

How long until pain appears?

Answer 47

Several hours

Question 48

How will the pain feel?

Answer 48

Mild aching

Question 49

What are teeth going to be sensitive to?

Answer 49

Pressure

Question 50

How long will the soreness last?

Answer 50

2-4 days

Question 51

When will teeth be sensitive again?

Answer 51

Reactivation

Question 52

There is a great deal of ___________ variation when it comes to pain

Answer 52

individual

Question 53

Does root resorption continue after braces?

Answer 53

No, if you stop the forces as soon as you notice resorption

Question 54

What decreases as a result of ortho treatment? How much?

Answer 54

Alveolar crest height; 0.5mm

Question 55

What determines alveolar bone position?

Answer 55

Tooth position (exception: ortho during active perio)

Question 56

Sometimes, an erupting tooth can bring alveolar bone with it. Describe the example given in class

Answer 56

Missing lateral incisor Canine erupts mesially then moved back to its proper position, creating alveolar bone for the implant

Question 57

Why is there an increase in mobility with ortho?

Answer 57

Bone remodeling (immature bone) PDL reorganization (disorganized) Widened PDL space

Question 58

How does the pulp respond to force?

Answer 58

Initial inflammation (no long-term signficance)

Question 59

In what cases have there been reports of loss of tooth vitality during ortho tx?

Answer 59

History of previous trauma Apex outside alveolar process

Question 60

Is it contraindicated to move teeth treated by endo?

Answer 60

No, you can do that! Response of the PDL, not the pulp, is key element in ortho movement