Normal Facial Development

Question 1

Describe the 2 ways bone is laid down

Answer 1

Endochondrial ossification- within cartilage
Intramembraneous ossification- within membrane

Bone is then remodelled by laying down or removing bone from surface

Question 2

What are the components of the Calvarium

Answer 2

6 fontanelles
Allows compression of the head at birth
Bone laid down by intramembraneous ossification

Question 3

Describe the 6 fontanelles of the Calvarium

Answer 3

Anterior fontanelle
Posterior fontanelle
2x anteriolateral
2x posteriolateral

5 out of 6 fuse during 1st year

Anterior fontanelle closes by 18 months

Question 4

What does the Calvarium grow in response to?

Answer 4

Brain growth

Question 5

Describe an abnormality in Calvarium growth

Answer 5

Craniosynostosis
Premature fusing of sutures on the Calvarium
Creates abnormal shaped head

Question 6

What are the two main areas of cartilage that make up the cranial base?

Answer 6

Synchondroses

Question 7

By what means of ossification are synchondroses made?

Answer 7

Endochondreal ossification

Question 8

Describe the 2 synchondroses

Answer 8

Speno occipital- fuses at puberty
Sohenoethmoidal- fuses at age 7

Inter sphenoid - divides the sphenoid bone in 2

Question 9

What components are there to the Nasomaxillary complex?

Answer 9

Maxilla
Nasal septum
Zygomatic bones

Question 10

How does the Nasomaxillary complex grow?

Answer 10

Intramembraneous ossification at sutures and surface re modelling

Question 11

Describe features of the mandible

Answer 11

Endochondreal activity at condyle
Periosteal activity/ surface re modelling

Mandible can have late growth in early 20s

Facial growth complete in women- 16-17 men 17-19

Question 12

What parts of orofacial musculature can influence dental arches?

Answer 12

Lips
Tongue
Cheeks

Well developed at birth re.suckling/ maintaining airway

Question 13

With growth, what does orofacial musculature develop to allow for?

Answer 13

Mastication
Facial expression
Mature swallowing
Speech

Question 14

What is the function of lips tongue and cheeks re tooth eruption?

Answer 14

They guide teeth into position during eruption

Question 15

Describe development of the dentition at birth

Answer 15

Edentulous
Gum pads
Designed for suckling

Question 16

Describe thee development of the dentition in deciduous dentition

Answer 16

Teeth start to erupt at 6 months
Primary dentition complete by 3
Root formation complete 18 months after eruption
All teeth have calcified in utero

Question 17

Describe the development in dentition in the mixed dentition

Answer 17

Deciduous start to exfoliate around 6 years
Permanent dentition complete by 13( except 8s)
Root formation complete 3 years after eruption

Question 18

How are permanent teeth accommodated?

Answer 18

Bigger arc
Growth of jaws
Spacing in deciduous

Question 19

Describe what in meant by leeway space

Answer 19

Buccal deciduous teeth are wider than permanents- the difference is leeway space

Leeway space is greater in the mandible

Allows 3,4 and 5s to be easily accommodated as long as no early loss of deciduous

Question 20

Describe the development of the dentition in permanent dentition

Answer 20

Teeth erupt until they occlude
Relationship of teeth influenced by underlying position of maxilla and mandible
Growth of maxilla and mandible can catch up in puberty
Class 3 more likely to get worse in males

Question 21

What late changes can occur in then permanent dentition?

Answer 21

Commonly lower incisal crowding during late teens/ early 20s
Due to late growth of mandible and Mesial drifting of all teeth

Not related to eruption of 8s

Question 22

Name the 4 main hard tissue components of the face

Answer 22

Calvarium
Cranial base
Nasomaxiallary complex
Mandible