craniofacial growth Flashcards
experimental techniques
1) bjork metal implants
2) vital staining
3) radioisotopes
- focus on site of growth, direction, duration, and amount
bjork
1) metal nails which are put in upper and lower jaw
2) xrays of where growth occurs
3) invasive, not done anymore
vital staining
1) dye in madder plant = alizarin
2) used in bone research
3) discovered in animals who ate the plants
radioisotopes
1) technetium 33
2) calcium 45
3) potassium 32
- diagnostics of bone tumors
cervical vertebral maturation
1) you can adjust parts of it
2) can extrapolate this for growth of mandible
cellular level growth
1) hypertrophy
2) hyperplasia
3) secretion of ECM (both size and number)
hard tissue
1) bones, teeth, cartilage sometimes
soft tissue
1) non calcified
2) other tissue aside from bones and teeth
growth of soft tissue
1) hyperplasia and hypertrophy
2) interstitial growth inside the tissues
growth of hard tissue
1) hyperplasia and/or hypertrophy
2) addition to surface = periosteum
3) no interstitial growth possible in calcified area, only remodel
periosteoum
1) soft tissue covering bone
2) new cells => more ECM => mineralization => new bone
hard tissue summary
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
epiphyseal plate
1) uncalcified cartilage for growth of limb
2) periosteum has important role in adding to the thickness
endochondral ossification
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
growth of craniofacial skeleton
1) cranium
- vault
- base
2) face
- nasomaxillary complex: nose, maxilla, associated small bones
- mandible
basic forces
1) compression, tension
combination forces
1) shear and bending
2) all four is torsion
maxilla
1) bones grow similarly
synchondrosis
1) filled with cartilage
2) bone formation proceeds by cartilage replacement
3) cartilage at synchondrosis is capable of independent growths
cranial vault
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
mandible
1) very different in the way it grows
cranial base
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
suture
1) only periosteum and CT
2) no direct ossification
3) connective tissue at sutures only reacts to chat happens in its surrounding
nasomaxillary complex
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
maxilla
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
posterior border of maxilla
1) free surface
2) bone added to this area, creating additional space into which the molar teeth can erupt
maxilla remodeling
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
maxilla translation
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
madnible
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
alveolar base
1) alveolar processes of maxilla and mandible grow as the teeth erupt, brining bone with them
