Growth and Orthodontics Flashcards
With growth how does the head shape change and in which direction?
the face grows relative to the skull
Face grows mainly in height then and SP direction and least in width
Which jaw grows more in the A-P direction? Who did these studies?
the lower jaw grows more in the AP direction BUT there is wide variation
Bjork
How much does the ANB angle change by?
1 degree between ages 11-20
What types of pattern of growth occur in the head?
intramembranous
enchondrolal
Which bones grow via enchondral ossification and which are intramem?
Enchondral,: cranial base and mandibular condyle (condylar is fibrocartilage)
Intramembranous: all other bones
How can you restrain the maxilla?
head gear and functional
how can you restrain forward growth of the mandible?
you cant!
What are the two growth rotations that can occur?
forward and backward
How is growth controlled?
mainly genetic but some environmental
Which growth curves can be used to monitor facial growth?
tanner growth curves can be used to monitor stature which parallels facial growth
what happens to growth during puberty?
pubertal growth spurt, velocity increases again
When is the pubertal growth spurt in females?
12 years
when is the pubertal growth spurt in boys?
14 years
what is the standard deviation on the pubertal growth spurt ages?
2 years
when does the growth stop in girls?
16 years
when does growth stop in males?
18 years
what is the standard deveiation for the growth stop?
2 years
Can skeletal pattern be predicted?
- Not very reliably
2. Can assume that everyone grows more class 3 with age
Can the pubertal growth spurt be predicted?
No
Can predict the average age of growth spurt but can see what is happening
Can orthodontic treatment influence growth?
A little bit
What appliances can we use to influence the maxillary growth?
Head gear and functionals
What appliances are used to enhance the growth of mandible?
Functionals
1-2mm
T/F
There is nothin to restrain the growth of the mandible?
T
What can you use to increase anterior maxillary growth?
Reverse head gear
What is the significance of growth rotations?
Late incisor crowding
What is the clinical significance of growth in ortho?
- Unpredictable change in growth can affect treatment
- Excessive vertical growth can lead to AOB
- Treat class 3 cases later and treat class 2 earlier
- Growth helps to reduce overbites
- Growth essential for spontaneous alignment and space closure following extractions
- Orthognathic surgery should be after growth stops
- Implants placed once growth stopped
8.
How can you predict growth?
Tanner growth curves
What do tanner growth curves show?
Used to monitor stature which parallels facial growth
What does the head consist of?
The cranium and the face
Up until what age does the intercanine width increase?
Until age 10
T/F during growth the ANB angle gets larger?
F Because everyone becomes more class 3
By how much does the ANB angle reduce?
Between ages 11-20 it reduces by 1 degree plus or minus 2,5
What percentage of people will becomes more class 3 and class 2 and by how much?
15% by more than 3.5 degrees
5% by more than 6 degrees
What are the stages to mandibular growth ?
Intramembranous and secondary cartilage forms
Condylar cartilage is an example of this
Later growth and remodelling due to Intramembranous
T/F periosteal growth can be influenced by pressure and tension?
T
When is growth fastest?
In utero
What happens between birth and puberty?
Decrease in velocity
What happens to growth during puberty?
Reversal of the decreased velocity and during pubertal growth spurt and then there is a rapid decline
T/F most people will have a jaw relationship that remains the same with growth?
T
But some will have significant changs
What are the possible environmental changes that will affect frowth?
Nutrition: softer food
Mouth breathing: small effect on growth
Bottle feeding: no affect
Jaw tongue and lip exercises no affect
T/F you can tell when the pubertal growth spirt is happening?
T
