Tooth movement Histology Flashcards

1
Q

Two main types of tooth movement

A

Physiological and orthodontically

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2
Q

Physiological tooth movement (includes 3 things)

A
  1. Tooth eruption
  2. Migration or drifting movements of teeth
  3. Tooth movement during Mastication
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3
Q

Two reasons for migration/drifting of teeth physiological

A
  • Due to Missing teeth or Space loss

* Due to Facial Growth

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4
Q

Define tooth eruption

A

Vertical or axial movement of the tooth from its developmental position with in the jaw to its functional position in the occlusal plane.

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5
Q

Stages of eruption (list them)

A

pre-eruptive
eruptive
post-eruptive

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6
Q

Bone and tooth eruption involve what two things

A

• Involve bone remodeling and soft tissue removal

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7
Q

Define/explain migration or drifting of teeth

A

The ability of teeth to drift through the alveolar bone

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8
Q

Migration post eruption, significant? Direction

A

Minor changes
Mesial occlusal

(maintain proximal contacts)

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9
Q

Migration post eruption favors which direction

A

medial-occlusal post eruptive movement for maintaining inter proximal and occlusal contacts

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10
Q

Migration due to facial growth happens in which direction and why

A

ant and laterally due to an increase in the arch size

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11
Q

The arch does what as permanent molars develop and erupt

A

Arch increases posteriorly as molars develop

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12
Q

Alveolar bone growth with facial growth

direction?
In relation to what

A

The HEIGHT of the alveolus bone increases in relation to root growth as part of the facial growth.

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13
Q

Transverse movement stops when

A

Stops at age 7

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14
Q

Primary incisors smaller than permanent, how do we get space for the new bigger teeth? (2)

A

Accommodation for the increased dimension of the permanent teeth is made by Lee way space and incisors
liability

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15
Q

Leeway space

Define?
What is it important for?

A

A leeway space is created in the arches by the replacement of larger primary molars for smaller permanent premolars.

This is important and compensate for the incisor liability factor.

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16
Q

leeway space gained per quadrant in maxilla and mandible

A
  1. 5mm in max

2. 5mm in mand

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17
Q

INCISOR LIABILITY

define

A

The difference in space between the permanent incisors and the primary which is required for proper alignment of the permanent incisors is called incisors liability.

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18
Q

Normal forces of mastication can range between

A

(1-50kg)

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19
Q

Tooth movement during mastication occurs in cycles of what duration

What if mastication goes beyond this?

A

1 second duration- will feel pain if this goes longer than 1-2s

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20
Q

When we chew, how do teeth move

A

Teeth exhibit slight movement in the socket and return to their original position on withdrawal of the force.

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21
Q

What happens when chewing force is sustained for more than 1 second?
Explain

A

Periodontal fluid is squeezed out and pain is felt as tooth is
displaced with in the periodontal space

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22
Q

Width of PDL around the root

A

0.5mm

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23
Q

PDL is made of (2)

A

collagen fibers and tissue fluids

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24
Q

PDL function **

What helps maintain movement of tooth?

A

Resists displacement of the teeth during normal function

Tissue fluid=movement

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25
Cellular elements of PDL (3)
Cellular elements mesenchymal cells neural vascular
26
Stem cell of fibroblast and osteoclast
Mesenchymal cells
27
Stem cells of osteoclast and cementoclasts
Hematopoitec
28
Structures involved in the biology of orthodontic tooth movement (5)
* External orthodontic Forces * Tooth * Periodontal ligament * Alveolar Bone * Extracellular fluid
29
WHAT HAPPENS DURING ORTHODONTIC TREATMENT? What causes tooth movement? What happens to the bone?
Prolonged forces on a tooth will result in tooth movement The bone surrounding the tooth remodels Remodeling = bone is removed (resorption) in some areas and added (apposition) in other areas
30
With bone remodeling what happens (think how and with what the tooth moves)
The tooth moves in the bone carrying its attachment apparatus with it (PDL), as the socket of the tooth migrates.
31
Response to orthodontic force is mediated by what
PDL
32
The _______ is constantly being remodeled and | renewed during normal physiological function.
collagen of the ligament
33
Remodeling of collagen in the PDL during normal function is caused by what
This is preformed by the fibroBLASTS producing new collagenous matrix materials, and fibroCLASTS removing it.
34
Bone changes physiological vs orthodontic Bone, which is more intense? why?
The alveolar bone and cementum is constantly being remodeled, though on a smaller scale, as a response to normal function. However, during the orthodontic treatment the remodeling process is more intense, due to the prolonged period of force applied to the teeth.
35
The PDL resists forces of _____ from chewing.
short duration (1-5seconds)
36
The ____ has the potential to “generate forces” which promote tooth movement in the case of eruption of teeth; and to counter unbalanced forces under normal conditions (stabilization).
PDL
37
What absorbs force while we chew Be specific
The periodontal ligament space filled with **tissue fluids** and the supporting alveolar bone are designed to absorb the forces of normal function e.g. Chewing.
38
When a tooth is subjected to heavy loads of (Chewing forces of less than _____ displacement of the tooth within the PDL space is prevented by the incompressible tissue fluid.
1 second
39
The force beyond 1s is absorbed by what? How does this structure respond? What does this create?
absorbed by alveolar bone which bends back and produces piezoelectirc currents within the bone
40
Response of bone bending under force causes
piezoelectirc currents
41
Physiological response to heavy force of <1 second | 3
1. PDL fluid compressed 2. Alveolar bone bends 3. Piezoelectric signal generated
42
Physiological response to heavy force of (1-2 seconds) 2 things
PDL Fluid expressed Tooth moves within the PDL space
43
Physiological response to heavy force of 3-5s 3 things
PDL fluid squeezed out Tissue compressed Immediate pain if pressure is heavy
44
WHAT HAPPENS IN THE CASE OF ORTHODONTIC TOOTH MOVEMENT? Think F and response
• Prolonged forces generated by the orthodontic appliance produces a different response in the PDL • Remodeling of adjacent bone results in tooth movement
45
A force on a tooth will create 2 opposite sides; what are they called? Describe
one is called | Pressure/or compression) side, the other is called (Tension
46
Cellular response on the pressure or compression side
Osteoclasts will resorb the bone of the socket wall (resorption) so the tooth can move **KNOW THIS
47
On the tension side what is the cellular
Osteoblasts will deposit or add bone on the opposite side of the socket (apposition). **KNOW THIS
48
Blood flow as teeth move
it is altered/cut off --> change in chemical environment --> cell differentiation and activity that is about all for now
49
LIGHT FORCES VERSUS HEAVY FORCES IN ORTHODONTIC TOOTH MOVEMENT Consider blood flow cell response and timing tooth moving method of tooth movement
``` For light Forces.. • Blood flow is compressed but not cut off totally, with survival of PDL cells. • Osteoclasts recruitment in 2 days. • Tooth movement is faster. • Tooth movement by frontal resorption ``` For Heavy Forces • Blood flow cut off for days • Osteoclast recruitment from PDL space not possible immediately, delayed 7-14 days. • Tooth movement is slower. • Tooth movement is by underside resorption of lamina dura = undermining resorption
50
apply more forces, will teeth move faster? Explain
NO! With optimal force osteoclast are recruited quicker. With heavy forces blood supply is cut off and osteoclast will not come as fast
51
Movement of heavy forces is where? What is this called
Under the lamina dura, called undermining resorption-INDIRECT
52
During light force, Tooth movement happens by _____
Frontal resorption-DIRECT
53
Pain with light or heavy forces?
More with heavy, also maybe necrosis
54
Optimal force must be high enough to do what and low enough to do what
* High enough to stimulate cellular activity. * Low enough so blood vessels in PDL not occluded • Biologic effect of tooth movement is determined by force level and area of PDL that force is distributed (force per unit area)
55
• Light Force – stimulates cellular activity, remodeling by _____
direct (frontal) | resorption
56
• Heavy Force – creates areas of hyalinization, pain, remodeling by ______
indirect | (undermining) resorption
57
As force is added, vessels do what
No force=normal Light = vessels in PDL area constricted/compressed Heavy=blood flow to PDL cut off
58
Blood vessels on tension side
=Tension side, (apposition by osteoblasts), stretched blood vessels in PDL.
59
Compression side vessels
Compression side, (resorption by osteoclasts), compressed blood vessels in PDL.
60
Areas of beginning of the root resorption that will be repaired by what
later deposition of cementum
61
Orthodontic tooth movement requires a well-coupled combination of ____ and ______ as the tooth socket remodels in response to the force systems established through the orthodontic appliance
resorption and | apposition
62
Orthodontic tooth movement is mediated by the PDL through localized changes induced by areas of _____ and _____within the PDL
compression and tension
63
Excessive force for a long duration is destructive to the | 3
bone, teeth, and pulpal tissue
64
Forces need to be controlled in terms of 3 things in order to effectively move teeth orthodontically.
direction, duration, and magnitude
65
NEGATIVE EFFECTS OF ORTHODONTIC FORCE | 4
• Tooth Mobility – remodeling of adjacent bone and the fibers of PDL results in widened PDL space during treatment. Teeth become more mobile. • Pain – heavy pressures create immediate pain, the pressures used in routine treatment do not produce immediate pain, pain or discomfort occurs 2-4 days following the adjustment • Pulp – orthodontic forces create a transient inflammatory response within the pulp, orthodontic tooth movement will not devitalize teeth and non vital teeth can be moved. • Root Resorption – the cementum is affected by the resorptive process at the same time as the osseous tissue is. The root undergoes remodeling and is generally restored when orthodontic forces on the root cease.
66
Pain – heavy pressures create immediate pain, the pressures used in routine treatment do not produce immediate pain, pain or discomfort occurs____ days following the adjustment
2-4
67
Tipping of the crown to the left, causes the root to ______ the PDL on the upper and lower left. ______ on the upper right and lower left.
compress tension
68
Bodily movement of the crown and the root to the left causes _____ to the left on the PDL. ___ on the right side.
compression tension
69
Blood vessels at tension side in PDL
Stretched
70
WHY RETENTION IS NEEDED AFTER TOOTH MOVEMENT IS COMPLETED? | 3
* Gingival fibers and PDL fibers take long time to reorganize after treatment is completed * Gingival fibers rearrangement take longer time (at least one year) compared to the PDL (few months) • It is very important to place a retainer to stabilize tooth movement after the completed. to the PDL fibers that take (few months). completion of the orthodontic treatment.
71
function of gingival ligaments and PDL
they vary-just know that
72
Compare the timing of rearrangement of gingival fibers and PDL
Gingival fibers rearrangement take longer time (at least one year) compared to the PDL fibers that take (few months).
73
Why is it important to | place a retainer to stabilize tooth movement post treatment
because the ligaments take a while to stabalize
74
Orthodontic tooth movement requires what (2) **KNOW THIS
Orthodontic tooth movement requires a well-coupled combination of resorption and apposition as the tooth socket remodels in response to the force systems established through the orthodontic appliance.
75
Ortho tooth movement is mediated by what **KNOW THIS
Orthodontic tooth movement is mediated by the PDL through localized changes induced by areas of compression and tension within the PDL.
76
bone resorption and formation is regulated by what (2)
Bone resorption and formation is regulated by the dental | follicle and enamel organ.
77
As a tooth migrates, what happens to its PDL
The tooth moves in the bone carrying its attachment apparatus with it, as the socket of the tooth migrates.
78
Force and tooth movement to the left will cause what two things
Pressure/compression on the left with osteoclast and tension on both roots with osteoblast on the right side of both roots