biomechanics of tooth movement

Question 1

tooth movement catagories

Answer 1

physiological

orthodontics

Question 2

physiological types of tooth movement

Answer 2

pre eruptuve
eruptive
post eruptive

Question 3

where do permanent teeth tend to form

Answer 3

lingual/palatal side of primary teeth

Question 4

rate of eruptive tooth movemnt

Answer 4

1mm per month

Question 5

post eruptive movement

Answer 5

accommodate to growing jaws
accommodate for occlusal wear
compensate for interproimal wear - mesial drift

Question 6

when can you move a tooth

Answer 6

need vital PDL

- tooth cannot be ankylosed

Question 7

PDL consists of

Answer 7

cells

extracellular components

Question 8

what may be responsible in the PDL for relapse after tx

Answer 8

collagen fibre bumdles

oxytalan fibres

Question 9

what occurs on the pressure side of the moving tooth

Answer 9

where the PDL is being compressed
- differentiation of osteoclasts
collagen fibre remodelling

Question 10

tension side of moving tooth

Answer 10

bone deposition

collagen fibre remodelling

Question 11

stages of movement

Answer 11

initial compression
delay phase (2-14) - cells need to move to area and activate
tooth movment

Question 12

initial compression

Answer 12

slight movement against wall of PDL

tooth moves through PDL

Question 13

delay phase

Answer 13

loss of cells from area
new cells move in
bone resorption

Question 14

tooth movement

Answer 14

PDL has new cels
bone resoprtion
collagen fibre remodelling

Question 15

threshold duration of fore

Answer 15

min 6hrs per day

longer force applied more efficient the movement

Question 16

excessive force application consequenes

Answer 16

blood vessels occluded on pressure side
cell death, delay in recruitment, have to be recruited outside the PDL
OC recruited from endosteal surface of bone, slower movement

hylinization and undermining resoprtion(described above)

Question 17

risks with excessive force application

Answer 17

1) delay in tooth movement
2) pain
3) loss of vitality
4) mobility
5) root resorption
6) loss of anchorage

Question 18

what does optimum force depend on

Answer 18

size of tooth
type of movement
continuous or intermittent

Question 19

orthodontic anchorage

Answer 19

control of unwanted tooth movement

- there is an equal and opposite force pushing other teeth eg the molar which a tooth may be anchored to

Question 20

types of movement

Answer 20

tipping
bodily movement
rotation
torque 
vertical movement (extrusion, intrusion)

Question 21

what type of movement do removable appliances do

Answer 21

only tipping

fixed do all (3D movement)

Question 22

types of movement and their ideal forces

Answer 22

bodily movement 70-120
root uprighting 50-100
rotation - 35-60
extrusion 35-60
tipping 35-60
 intrusion 10-20

Question 23

cellular event in responce to mechanical loading

Answer 23

matrix strain and fluid flow in the alveolar bone and PDL
cell strain as a result of matrix strain and fluid flow
cell activation and differentiation
remodelling of PDL and alveolar bone

Question 24

how and what is hylinization /how does it occur

Answer 24

force applied to tooth exceeds pressure in capillaries 30mmHg capillaries will occlude
cell dealth in PDL
sterile necrosis
- which is hylainzation