Facial Growth Flashcards
(114 cards)
why is facial growth important
The size, shape and position of the underlying jaws determines the position of the teeth and therefore the malocclusion
describe

Class 3, reverse overjet, low angle
- Jaw different sizes
- Slight asymmetry

describe

Class 2 div 1, increased overjet, high angle, mandibular retrognathia, upper jaw in right place (lower jaw too small is the issue – functional app in young, orthognathic surgery in adult)

why is the study of facial growth important to orthodontics
- Insight into growth of the face
- predict changes – interceptive treatment
- utilize growth to correct malocclusion – grow mandible (vertical more than AP)
- time our orthodontics and surgery – only do surgery when completed growth
- Understand development of facial anomalies
- To measure changes in growth and treatment using cephalometry
treatment and favourable growth = success
2 phase of IUL
embryo 1-8 weeks (A - everything develops)
foetus 8 week to term (B - growing)

when are all limbs, organs and face formed
within the first 2 months and the embryo has a characteristic human form
- External environmental influences can cause cranio-facial abnormalities very early on in the pregnancy
- 10% of embryos miscarry – things don’t run like clockwork (deformities)*
- After the initial 8 weeks significant drop*
day 1
fertilised egg (0.1mm)
2 nuclei

day 2-3
0.1mm still

Dividing – many cells (8-16)
Floating done fallopian tube
Still in egg like zona pellucida
Called morula
day 4-5
still 0.1-0.2mm
Blastocyst
Now 16-32 dells
- Cells divided to make a cyst
1 – inner cell mass (ICM) -> baby
Everything else placenta etc
Just before implantation egg hatches – lose zona pellucida
Begin to form ectoderm and endoderm

day 9
still 0.1-0.2mm
implantation
begin to develop germ layers

day 17
still 0.2mm

Germ layers formed – germ disk (made of ectoderm and inside is endoderm (8))
Primitive node/streak – fold – ectoderm folds in to create 3rd layer mesoderm (7)
day 25-28 (week 4)
By 4 weeks beginning to grow in size
Somites along back
Neural grove forms neural tube

neural crest cell migration
very important in the development of the face (cranial)
- Ectomesenchyme
- Originally ectoderm but migrate in, flood forward and help form pharyngeal arches = imp for facial development

cells develop into face
cranial neural crest cells (after migration)

migrated neural crest cells form
ECTOMESENCHYME
- Originally ectoderm but migrate in, flood forward and help form pharyngeal arches = imp for facial development
neural tube
- neural folds fuse to form the neural tube, towards the end of week three
failure to fuse will lead to spina bifida
failure of neural folds fusion
spina bifida
neural tube develops into
- brain and spinal cord.
failure to develop neural tube
Failure to develop will lead to anencephaly
(in which the cerebral hemispheres and the cranial vault are absent)
neural crest cells form
- During the folding of the neural plate, cells develop from the ectoderm along the edge of the groove, termed neural crest cells.
neural crest cell role
These undergo extensive migration within the developing embryo and ultimately differentiate into many cell types
e.g. spinal and autonomic ganglia; Schwann cells, adrenal medulla, meninges of the brain.
neural crest cells derived from ectomesenchy,e contribute to
branchial arch cartilage, bone and connective tissue proper, as well as dental tissues - pulp, dentine, cementum and periodontal ligament.
- Vital for tooth development
tooth development from
neural crest cells derived from ectomesenchyme
day 30
- Embryo getting larger*
- Beginning to get pharyngeal arches*
- Frontal nasal processes at top (P) neural crest cells flooding in from here*
- Learn arches and what they formed*
- 1st, 2nd and 3rd formed and bulked by neural crest cells flooding in*











































