craniofacial growth

Question 1

experimental techniques

Answer 1

1) bjork metal implants
2) vital staining
3) radioisotopes
- focus on site of growth, direction, duration, and amount

Question 2

bjork

Answer 2

1) metal nails which are put in upper and lower jaw
2) xrays of where growth occurs
3) invasive, not done anymore

Question 3

vital staining

Answer 3

1) dye in madder plant = alizarin
2) used in bone research
3) discovered in animals who ate the plants

Question 4

radioisotopes

Answer 4

1) technetium 33
2) calcium 45
3) potassium 32
- diagnostics of bone tumors

Question 5

cervical vertebral maturation

Answer 5

1) you can adjust parts of it
2) can extrapolate this for growth of mandible

Question 6

cellular level growth

Answer 6

1) hypertrophy
2) hyperplasia
3) secretion of ECM (both size and number)

Question 7

hard tissue

Answer 7

1) bones, teeth, cartilage sometimes

Question 8

soft tissue

Answer 8

1) non calcified
2) other tissue aside from bones and teeth

Question 9

growth of soft tissue

Answer 9

1) hyperplasia and hypertrophy
2) interstitial growth inside the tissues

Question 10

growth of hard tissue

Answer 10

1) hyperplasia and/or hypertrophy
2) addition to surface = periosteum
3) no interstitial growth possible in calcified area, only remodel

Question 11

periosteoum

Answer 11

1) soft tissue covering bone
2) new cells => more ECM => mineralization => new bone

Question 12

hard tissue summary

Answer 12

1) direct addition to calcified tissue on its free surfaces
2) replacement of soft tissue that grew before calcification occurs
- many bones are modeled in cartilage before endochondral ossification

Question 13

epiphyseal plate

Answer 13

1) uncalcified cartilage for growth of limb
2) periosteum has important role in adding to the thickness

Question 14

endochondral ossification

Answer 14

1) bone formation on surface of cartilage
2) ossification of center
3) invasion of vessels in center
4) front of bone formation on either end
5) ingrowth of vessels
6) ossification centers in cartilaginous caps on either end

Question 15

growth of craniofacial skeleton

Answer 15

1) cranium
- vault
- base
2) face
- nasomaxillary complex: nose, maxilla, associated small bones
- mandible

Question 16

basic forces

Answer 16

1) compression, tension

Question 17

combination forces

Answer 17

1) shear and bending
2) all four is torsion

Question 18

maxilla

Answer 18

1) bones grow similarly

Question 19

synchondrosis

Answer 19

1) filled with cartilage
2) bone formation proceeds by cartilage replacement
3) cartilage at synchondrosis is capable of independent growths

Question 19

cranial vault

Answer 19

1) number of flat bones formed from periosteum
- entirely periosteal activity
2) widely separated bones allow considerable deformation that is important for getting a relatively large head through birth canal
3) most growth at sutures: apposition of bones along edges of fontanelles
- major mechanism of growth

Question 19

mandible

Answer 19

1) very different in the way it grows

Question 19

cranial base

Answer 19

1) formed by cartilage
- endochondral replacement
2) bands of cartilage called synchondrosis remain between bones
- important growth sites:
- spheno-occipital
- inter-sphenoid
- spheno-ethmoidal
3) synchondrosis looks like epiphyseal plate, same process

Question 20

suture

Answer 20

1) only periosteum and CT
2) no direct ossification
3) connective tissue at sutures only reacts to chat happens in its surrounding

Question 21

nasomaxillary complex

Answer 21

1) intramembranous
2) no preexisting cartilage
3) sutures and surface remodeling
4) grows postnatally downward and forward from the cranium
- sutures posteriorly along maxillary tuberosity
- superiorly at end of frontal process
- superiorly-laterally along the zygomatic process
- more sutures are in the midline and down the midline of the palate

Question 22

maxilla

Answer 22

1) apposition at the suture and remodeling of the surfaces
2) downward and forward repositing of maxilla
3) new bone added at sutures to maintain connection to cranium

Question 23

posterior border of maxilla

Answer 23

1) free surface
2) bone added to this area, creating additional space into which the molar teeth can erupt

Question 24

maxilla remodeling

Answer 24

1) growing down and forward, and front surfaces are remodeled and bone is removed from most of the anterior surface
2) almost whole anterior surface is a resorptive area

Question 25

maxilla translation

Answer 25

1) whole bone moving down and forward
2) front surface is being reduced anteriorly
3) it is being built up posteriorly
4) so front surface moves in space opposite to direction of overall growth
5) floor of the node is resorbing and bone is added to roof of the mouth
6) front surface below the anterior spine is resorbing, so surface change opposes the direction of translation in this area

Question 26

madnible

Answer 26

1) chin moves downwards and forward in relative to cranium
- AKA the growth and modeling of the ramus is moving posteriorly (makes space for molar to erupt)
2) large amount of bone is removed from anterior of the ramus
3) apposition and remodeling resorption at the ramus, and by endochondral replacement at the condyles

Question 27

alveolar base

Answer 27

1) alveolar processes of maxilla and mandible grow as the teeth erupt, brining bone with them