Tooth Movements

Question 1

why are some examples of tooth movements

Answer 1

functional tooth movements
mesial drift
orthodontic tooth movements

Question 2

what are the occlusal forces

Answer 2

greater between molars
70-150N dentate
4-55N edentulous

Question 3

what are the max clenching forces between molars

Answer 3

500-700N

Question 4

what plane has greater movement

Answer 4

greater movement in horizontal plane (100Um) 
lesser vertical (10Um)

Question 5

what are some tooth support components

Answer 5

bone
PDL fibres
PDL fluids

Question 6

what is the system that response in tooth movement to load

Answer 6

visco-elastic system

- not purely elastic there is a viscous property due to PDL fluids

Question 7

what are some factors affecting tooth movement

Answer 7

slow rate load - greater move
anger tooth load- slower rate
tooth not loaded- less mobile
more tooth loaded - tooth displaced less mobile

Question 8

what is the implication of response to repeated application of a 5N loa

Answer 8

occlusal accuracy of precision impressions

indirect restorations

Question 9

what si the viscous element of disco elastic support of tooth

Answer 9

ECM - aggregates at rest less mobility

PDL fluids - interstitial and blood

Question 10

what is the elastic element of the visco elastic tooth support

Answer 10

collagen
bone
osseointgrated implants
- pure elastic

Question 11

how is an osseoimpant supported

Answer 11

no pDL
elastic suppor form bone
much less movement

Question 12

what are the support of normal tooth

Answer 12

PDL bone

viscoelastic support

Question 13

what are the similarities of PDL to tension bearing CT

Answer 13

oblique fibres
sharpens fibres
fibroblast shape and orientation
GAGs

Question 14

what are the differences of PDl to tension bearing CT

Answer 14

small diameter of collagen fibres
scarcity of sharply fibres in lamina dura
quantities of ground substance

Question 15

what are post eruptive tooth movements

Answer 15

vertical
buccal
mesial
othrodontic

Question 16

what is th buccal posts eruptive movement

Answer 16

growth of jaws

bone remodelling

Question 17

what is the vertical post eruptive movements

Answer 17

continued eruption
compensation of wear
bone depo
cementum depo

Question 18

when does mesial drift occur

Answer 18

thourghout life

Question 19

what is media drift

Answer 19

drift i metal director towards arch midline

Question 20

what si the result of mesial drift

Answer 20

compensates approximal wear 
incised crowding 
shorten dental arch 
orthodontic relapse 
space closure follow tooth loss

Question 21

how much is an example of 6-18 years of missal drift

Answer 21

3-4mm

Question 22

what is am example of effect of a hard diet on mesial draft

Answer 22

move of 7mm

Question 23

what si the extrinsic mech to peridontium for mesial drift

Answer 23

occlusal forces
muscular soft tissue forces
erupting molars

Question 24

what is the intrinsic mech to periodontium for mesial drift

Answer 24

bone remodelling

PDL Fibres - transeptal Fibrs

Question 25

are occlulsa loads the same

Answer 25

no transient

Question 26

approximal tooth wear must have

Answer 26

fore pushing teeth together

Question 27

what is the effect of no opposing teeth on mesial drift

Answer 27

still drift faster rate no occlusal interlocking

Question 28

what is the effect of flattened cusps on mesial drift

Answer 28

faster rate | no occlusal interlocking

Question 29

what does reshaping cusps do on mensal drift

Answer 29

side favour drift faster side oppose drift slower

Question 30

what does a 9Kg load occlusal result in a horizontal load

Answer 30

2.25kg against molars | 5kg against kilograms

Question 31

when clench occusally what is produced

Answer 31

anterior vector to closing force

Question 32

do occlusal forces effect mesial drift

Answer 32

partly involved | but not most important factor

Question 33

what are the effects of the soft tissues

Answer 33

(cheeks + buccinator) | not likely to play a role

Question 34

what is the evidence of the forces from erupting molars

Answer 34

extraction of premolars | spaces more rapidly when molars erupt

Question 35

what is the evidence against forces rom erupting molars

Answer 35

mesial drift occurs through life - after molars erupted still get mesial drift anterior to any ankylosed tooth

Question 36

what sit he evidence of bone remodelling with mesial drift

Answer 36

happens sometime as mesial drift

Question 37

what si the evdicen against bone remodelling

Answer 37

marker experiments show that bone fills in | effect not cause

Question 38

what do transeptal fibres do

Answer 38

maintain tooth contact stabilise tooth position less orthodontic relapse if cut

Question 39

what sit he picots and moss

Answer 39

process elimination PDL involved cut transeptal fibres mesial drift slowed

Question 40

what is mesial drift therefore dept on

Answer 40

multifactorial - greatest PDL transeptal fibres - occlusal factor - not erupting molars

Question 41

what are some factors inleucneing position teeth in the arch

Answer 41

``` eruption position jaw growth guidance adjacent or opposing teeth mesial drift soft tissue forces sucking thumb suck ```

Question 42

what are th basics of orthodontic tooth movements

Answer 42

small continual forces - bone remodel PDL remodel - tooth move

Question 43

what are the 3t types of orthodontic tooth movement

Answer 43

tipping bodily rotational

Question 44

what is tipping movement

Answer 44

tension and compression | movements and hence forces greater the further away form he fulcrum

Question 45

what is bodily move

Answer 45

compression going into mouth form tension at the front aspect force on crown

Question 46

how much force used orthodontically

Answer 46

ideally close to natural forces | less than PDL capillary pressure

Question 47

what happens if force > PDL cap pressure

Answer 47

ischaemia

Question 48

wha tis the force of - tipping - bodily - rotational - extrusion - intrusion

Answer 48

``` 30-60g 60-120g 30-60g 30-60g 10-20g ```

Question 49

what do light fires do

Answer 49

``` compression = frontal resorption (osteoclasts) tension = deposition from osteoblasts ```

Question 50

what do heavy forces do

Answer 50

hyalinisation | tension - depo - osteoblasts

Question 51

what is hyalinisation

Answer 51

compression ++ exceed cap pressure = sterile necrosis/cell death/translucent appearance = undermining endosteal resorption

Question 52

what are some possible effects of excessive forces

Answer 52

``` pain - ischaemia - inflam - necrosis unprepared hyalinisation pulp death- strangle vessels at apex root resorption - odontoclast ```

Question 53

what are the means of stability and retention

Answer 53

remodel bone remodel principal collagen fibres need for retention

Question 54

what needs retention

Answer 54

long term permanent large space closure correction of severe rotations

Question 55

what are the ways of remodelling of principle collagen fibres

Answer 55

``` rapid below alveolar crest lower above alveolar crest - supralaveolar esp transeptal rotations ```