Normal Facial Development

Question 1

what are the 2 ways bone can be laid down

Answer 1

intramembranous ossification

endochondreal ossification

Question 2

define endochondreal ossification

Answer 2

within a cartilage
bone develops by replacing hyaline cartilage
cartilage does not become bone but is completely replaced to form new wbone

Question 3

define intramembranous ossification

Answer 3

within a membrane

compact and spongy bone is developed directly from sheets of mesenchymal (undifferentiated) connective tissue

Question 4

By which method are most cranial bones laid down?

Answer 4

intramembranous ossification

Question 5

how does bone remodel

Answer 5

by laying down or removing bone from the surface

Question 6

how do bones connect to each other and which bone in the head is an exception to this?

Answer 6

via sutures (non-moveable)
except the TMJ- only moveable joint in the head

Question 7

Name 4 types of facial hard tissues

Answer 7

Calvarium
Cranial Base
Naso-maxillary complex
Mandible

Question 8

what bones make up the calvarium (skull)

Answer 8

frontal
occipital
2 parietal

Question 9

how many fontanelles are present at birth and name them

Answer 9

6
1 anterior
1 posterior
2 anterilateral
2 posterolateral

Question 10

define fontanelles

Answer 10

space between the bones of the skull where ossification is not complete and sutures are not fully formed

Question 11

when do the fontanelles close and what happens after this

Answer 11

5 close by 12 months
anterior= 18 months
bone is laid down at the sutures and on the surface

Question 12

what do fontanelles allow?

Answer 12

compression of the head during birth

Question 13

what does the calvarium grow in response to

Answer 13

brain growth

Question 14

name an abnormality of calvarium growth and describe it

Answer 14

Craniosynotosis

premature fusing of the sutures of the skull causing an abnormal shaped head

Question 15

which bones make up the cranial base

Answer 15

frontal
occipital
2 parietal
2 temporal
ethmoid
sphenoid

Question 16

By which method is bone laid down within the cranial base

Answer 16

Endochondreal ossificstion

2 main areas of cartilage

Question 17

define synchondroses

Answer 17

cartilaginous growth sites- bone is laid down here and causes growth of the cranial base

Question 18

what are the 3 Synchondroses of the cranial base

Answer 18

sphenooccipital- between sphenoid bone and occipital- fuses at puberty
sphenoethmoidal- between ethmoid bone and sphenoid. fuses at 7 years
intersphenoid- divides sphenoid in to 2

Question 19

How is bone laid down within the calvarium

Answer 19

intramembranous ossification

Question 20

what makes up the nasomaxillary complex

Answer 20

maxilla
nasal septum
zygomatic bones

Question 21

how is bone laid down within the nasomaxillary complex

Answer 21

intramembranous ossification at sutures

and surface remodelling

Question 22

how are the nasomaxillary complex and the cranial base linked

Answer 22

nasomaxillary complex is pushed downwards and forwards and the cranial base grows

Question 23

Which bone is the only moveable bone in the skull

Answer 23

mandible

Question 24

where does the mandible form from

Answer 24

1st pharyngeal arch

Question 25

by which 2 methods does the mandible grow

Answer 25

endochondreal- condyle | periosteal activity/surface remodelling

Question 26

when is facial growth in males and female normally complete by?

Answer 26

males- 17-19 | females-16-17

Question 27

what does the orofacial musculature consist of and how does it affect the teeth

Answer 27

lipps cheeks tongue teeth lie in a position of equlibrium/neutral zone between the tongue and cheeks

Question 28

after orthodontic treatment, when is the influence of cheeks/tongue not important

Answer 28

if a patient is to wear permanent retainers

Question 29

reaosns why the orofacial musculature is important?

Answer 29

``` suckling maintaing airway mastication speech swallowing guide teeth during eruption act to compensate for skeletal discepancies ```

Question 30

what are neo natal teeth?

Answer 30

deciduous teeth that erupt early

Question 31

why can neo natal teeth be mobile

Answer 31

they have poor root formation

Question 32

how can neo natal teeth cause problems

Answer 32

interfere with feeding

Question 33

when do deciduous dentition start to erupt and when is eruption complete

Answer 33

start at 6 months | complete by 3 years

Question 34

when is root formation of deciduous teeth complete by

Answer 34

18 months after eruption

Question 35

when do deciduous dentition start to exfoliate?

Answer 35

6 years

Question 36

when is permanent dentition usually complete by?

Answer 36

13 years except 8s

Question 37

when is root formation of permanent teeth usually complete by

Answer 37

3 years after eruption

Question 38

what is the leeway space

Answer 38

deciduous D+E are wider than permanent successor so difference in space when permanent successors erupt is called the lee way space greater in the mandible

Question 39

when does the maximum growth of age occur

Answer 39

8-9 years as majority of teeth erupt at this stage

Question 40

when do teeth stop erupting

Answer 40

until they occlude each other

Question 41

what was late incisor crowding thought to be a result of

Answer 41

eruption of 8's but late incisor crowding still occurs whether or no 3rd molars are present

Question 42

what is thought to be the cause of late incisor crowding in late teens/early 20s

Answer 42

late mandibular growth