Gda Ortho 2

Front 1

Piezoelectric theory

Back 1

- current generated when force is applied due to remodeling
-current degrades to 0
-when force released opposite current genreated

Front 2

Cells in PDL

Back 2

-Collagen
-neurovascular
-fibroblast
-OSTEOBLAST
-undifferentiated mesenchymal

Front 3

Blood vessels in compression and tension

Back 3

comp: closing
Tension: dilation

Front 4

Physiologic Response to sustained pressure

Back 4

<1 sec: PDL fluid is incompressible, bone bends creating a piazoelectric signal

1-2 seconds: PDL fluide is expressed, tooth moves within PDL space

Front 5

Light Pressure

Back 5

3-5seconds: blood vessels in PDL slightly compress, dilate on tension, constrict on pressure-->cells mechanically distorted

Minutes: Blood flow altered, Oxygen tension felt, cytokines and PGs released

Hours: Metabolic changes: chemical messengers alter cell activity and enzyme levels changes

4 Hours: Increased cAMP levels, Cellular differentation w/i PDL

2 days: tooth movement begins with osteoblast/osteoclast remodeling(Frontal removdeling)

Front 6

Heavy Pressure

Back 6

3-5 seconds: Blood vessels occlured on pressure

Minutes: Blood flow cut off to PDL

Hours: Cell death in compressed area

3-5 days: Cell differentation in adjacent marrow spaces, underminding resoprtion beings)

7-14 days: undermining resoprtion removes LD adjacent to compressed PDL, tooth movement occurs

Front 7

Optimal force

Back 7

Transition between light foce and heavy force-->ideal for for tooth movement

Front 8

Types of movement

Back 8

Tipping: more crown movement than root movement
Translation:whole thing is movemet, root movement = crown movement
Root uprighting: root movement > crown movement
Force level: moving against pdl vs. air
Rotation: not as much force, more tension than pressure
Don’t need to worry about force levels
Do need to worry about potentially tearing PDL
Extrusion:
Tooth is being pulled out of the socket but still anchored by PDL
Lots of tension of PDL
Intrusion:
Tooth being pushed into the socket
Lots of pressure at apex, and some on the side
Some tension on the side as well

Front 9

Greater surface area?

Back 9

more force can be applied without surpassing optimal force

Front 10

Trasnlation optimal force?

Back 10

high due to high sruface area affected

Front 11

Intrusion optimal force?

Back 11

low due to small surface area

Front 12

Tooth movement efficeincy vs. duration of force

Back 12

-succesful tooth movmenet requires at least 6 hrs of force,
- take several hrs for cells processes of tooth movement to kick in to get actual movement
-boiling water analaogy...

Front 13

Effects of Force duration and force decay

Back 13

-loss of force magnitude overtime due to material loss of stregnth of tooth moving

-thus one needs to reactive ortho device to generate force after cerain time periods

Front 14

Light contnious vs. heavy continuous

Back 14

-light continuos -->frontal resoprtion
Heavy-->underminding-->avoid

Front 15

graph of reactivation

Back 15

-force level drops until reactivated

Front 16

interuppted force

Back 16

-Force level decreases to 0 b/w activations

Front 17

Intermintent force

Back 17

- Force levels abruptly decline to 0
-force levels still decline over time as movement occurs
-force levels can be increased with adjustment
-may decrease overall tooth movement but might also decrease undermining resorption

- may see tooth movement if cells are activated still

Front 18

Types of movement and force needed

Back 18

tipping: 35-60
Bodiy: 70-120
Root uprighting: 50-120
rotation: 35-60
Extrusion: 35-60
Intrusion 10-20

Front 19

Servosystem theory

Back 19

-NC/CB are growth centers
-NC/CB drive maxillary remodeling
-changes in maxillary--->occlsuion devaition-->condylar cartilage remodeling

Front 20

remodeling
sutural
nasal septum
fxnal matrix

Back 20

-periosteum
-sutures
-condylar cartilage, NS, CB GC
-soft tisse are GC

Front 21

Modification
NS/CB
CC
Periosteum
Suture

Back 21

- not modified
- may mod
- may mod
- can mod

Front 22

Forces at sutures

Back 22

-tensile-->apposition
-Compression-->no apposition
-fxnal matrix theory: fxn-->remodeling

Front 23

Transverse deficieny
- device and target

Back 23

-xbite
-target mid palatal suture appositon and expand palate
-.25mm per crank, .25mm = pdl space
-after first crank tooth up against pdl, next crank you'll be pushing on bone(pdl doesn't have time to respond) forcing suture open
- may have some underminding resoprtion

Front 24

Restrain maxillary growth
-target?
-device?

Back 24

-pressure at circumamxillay sutures and allow normal mandibular growth
-use head gear which uses 1st perm molars to create compressive force toward cm sutures
-can either use high pull occipital or low cervical

Front 25

Maxillary Force Restraint:
Force magnitude:
Duration

Back 25

500-1000 grams
12 hrs
12-18 months

Front 26

Maxillary growth
-tool?

Back 26

-facemask/protraction head gear which uses teeth as an abutment to transmit tensile force to cm sutures)forehead and chin are used as anchors

Front 27

Maxillary protraction
force
duration

Back 27

-1000g
-12 hrs a day/24 is ideal
-9-12 months

Front 28

Mandibular restraint
-tool?

Back 28

-restrict fxn of mandible and compress condyle with chin cup

Front 29

Mandibular restraint
-force
-duration?

Back 29

-heavy
-16 hrs/ 24 is ideal
-6 years

Front 30

Mandibular growth
-tool?>

Back 30

-bionator,twin block, herbst, MARA
-encourage mandibular growth by modifying fxn of the mandible
-force mandible into protrusion to stimulate condylar growth
-open forward-->stretch of msucles and soft tissue which transmit to dental and skeletal structures

Front 31

mandibular growth
force
duration

Back 31

-heavy
-16 hrs ideal 24 hrs
-12-18 months