Biomechanics and the Biology of Tooth Movement

PDL

The existence of the .... is what allows teeth to be moved orthodontically

.5

The PDL occupies a space ~.....mm in width around all parts of the root

Collagen fibers

what component of the PDL:

- connect the root of the tooth to the alveolar bone

- Purpose is to resist tooth movement during normal function

mesenchymal cells

what component of the PDL:

- Fibroblasts, osteoblasts, osteoclasts, cementoblasts, cemetoclasts

- Maintain and remodel the PDL, alveolar bone, and cementum

fluid

what component of the PDL:

- Shock absorber

nerve endings

what component of the PDL:

- Pain and proprioception

what time in heavy chewing force:

- No displacement

1-2 seconds

what time in heavy chewing force:

- Displacement of tooth within the PDL space

3-5 seconds

what time in heavy chewing force:

- PDL fluid leaves the PDL space, causing pain

- The pain is your body's signal to stop biting so hard

decreased

in Areas of compression-blood flow is .....

increased

Areas of tension-blood flow is static or .....

Prostaglandins

.... induce the formation of osteoclasts and osteoblasts

hyalinization

.... occurs when heavy forces cause lack of blood flow resulting necrosis in the areas

superior

Light continuous forces are ..... to heavy intermittent forces

scalar

......: Quantity that has only magnitude/value

Ex. Mass, volume, temperature, pressure

Vector

......: Quantity that has both magnitude/value AND direction

Ex. Velocity, acceleration, displacement, force

vector

Growth is a ....

center of resistance

Understanding orthodontic tooth movement is all about knowing where the ..... is located

2/3

The center of resistance of a tooth is approximately ...... of the distance from the root apex to the bone height

moment

- Any force that DOES NOT pass through the center of mass/center of resistance will have a rotational effect in addition to a translational effect

- This is called a .....

couple

• Two equal and opposite forces displaced by a distance, whose lines of action do not coincide

• causes an object to rotate around the center of mass/center of resistance