Theories of Craniofacial Growth (FINAL)

Question 1

In orthodontics they feel that by changing the environment/manipulating the growth patterns, they are positively influencing the:

Answer 1

Epigenetic patterns of genes

Question 2

The concept of the genes that you express or don’t express & to what degree:

Answer 2

Epigenetics

Question 3

Epigenetics are considered very:

Answer 3

Unpredictable

Question 4

In orthodontics they feel that by changing the environment/manipulating the growth patterns, they are positively influencing the epigenetic patterns of genes resulting in:

Answer 4

Correction of malocclusion

Question 5

The lower incisors & upper incisors DO meet with 25% overbite & they are in balance:

Answer 5

Interincisal cupping

Question 6

For the male patient seen with the 12 mm of overate (full class II malocclusion) the treatment required:

Answer 6

Orthognathic surgery

Question 7

Although the man who required orthognathic surgery’s son came in with the same genetics as his father (and some from his mother)- what treatment was decided and why?

Answer 7

Functional appliance to reposition the lower jaw forward (avoiding surgery); due to young age and not being done with growth

Question 8

What was the hope with treating the boy with a functional appliance?

Answer 8

We hope to have a 50% upper & lower correction of vertical dimension & that the dental alveolar processes respond to this new position

Question 9

Growth theory of Proffitt=

Answer 9

Equilibrium

Question 10

Theory that states not only should you look at the hard tissues & make inferences from this, but also the balance of forces that keep the jaws in their position & the duration of force (that is more important than the magnitude)

Answer 10

Equilibrium theory of proffitt

Question 11

The Equilibrium Theory of Profitt states that in addition to looking at the hard tissues you should also consider (2):

Answer 11

1. Balance of forces keep the teeth & jaws in their position
2. Duration of force more important than magnitude

Question 12

The Equilibrium Theory of Profitt states that the ____ of force is more important than the _____

Answer 12

Duration; magnitude

Question 13

The Equilibrium Theory of Profitt states that the balance of _____ keeps the teeth & jaws in their position

Answer 13

Forces

Question 14

The Equilibrium Theory of Profitt states considers the balance of what muscles?

Answer 14

1. Muscles of mastication
2. Lingual muscles
3. Orofacial muscles

Question 15

What does the Equilibrium Theory of Profitt state should be in balance? (3)

Answer 15

1. Bone
2. Soft tissue
3. Pharynx/nasal cavity/airway

Question 16

Means that the function requirements (breathing, eating, mastication, etc.) is very relevant to the development of your craniofacial complex:

Answer 16

Functional matrix

Question 17

The theory of functional matrix reverses the theory that:

Answer 17

The theory that we first have bone, bone grows, & tissues accomodate

Question 18

The functional matrix theory considers the balance between:

Answer 18

Cheek pressure & Tongue posture

Question 19

What positions does the tongue push on the teeth?

Answer 19

1. AP position
2. Transverse position
   (does NOT have massive influence on the vertical dimension)

Question 20

Discuss the relationship between bone growth & soft tissues portrayed by the functional matrix theory:

Answer 20

Bone growth <—-> soft tissue accommodation

(we just don’t know to what degree)

Question 21

Orthodontics has the capacity to influence growth thanks to:

Answer 21

Functional matrix

Question 22

Mouth breathing & sleep apnea may be due to:

Answer 22

Anterior open bite

Question 23

Enhancing dentoalveolar growth has an influence on the ________ but we do not know to what degree

Answer 23

Muscles

Question 24

Malocclusion that is 100% related yo functional alterations:

Answer 24

Open bite

Question 25

-Overeruption of alveolar processes -no equilibrium -jaws not developing enough in the transverse direction -everything is too small -tongue pushes on teeth All of this contributes to:

Answer 25

Open bite

Question 26

What condition may be correlated to an open bite?

Answer 26

Sleep apnea

Question 27

Dental affects on mouth breathing include: (5)

Answer 27

1. anterior open bite 2. maxillary incisor protrusion 3. mandibular incisor protrusion 4. narrowing of the maxilla 5. mandibular retrusion

Question 28

Mandibular retrusion (a component of open bite malocclusion) may be due to:

Answer 28

1. Mandible is genetically too small 2. Mandible may not be growing because functional matrix is not opsonized (likely lies somewhere in between!!)

Question 29

For the case of the patient with skeletal-dentoalveolar malocclusion, what was wrong with the maxilla & what was wrong with the mandible?

Answer 29

Maxilla= dentoalveolar (excessive vertical growth) Mandible= short ramus

Question 30

What treatment was used for the case of the patient with skeletal-dentoalveolar malocclusion?

Answer 30

Combination of dentoalveolar treatment with orthodontics, extractions & sagittal segment osteotomy

Question 31

What bones & where do growth CENTERS occur?

Answer 31

Epiphysis of long bones

Question 32

Where would we NOT find growth CENTERS?

Answer 32

No growth centers in the craniofacial complex (except for cranial base)

Question 33

Growth CENTERS are responsible for growth of:

Answer 33

Long bones

Question 34

How are cells organized in growth CENTERS?

Answer 34

Cells are layered in a precise manner

Question 35

What happens with a cell that is transplanted from a growth CENTER?

Answer 35

It will continue to grow (maybe due to chemical mediators or genetics)

Question 36

Do growth CENTERs respond to tension or pressure?

Answer 36

NO (tightly genetically controlled)

Question 37

Because growth CENTERs are tightly genetically controlled, this means:

Answer 37

No place for functional adaptation

Question 38

Where do we find growth SITES?

Answer 38

Mandibular condyles Maxillary sutures Maxillary tuberosity

Question 39

Discuss the cell organization of growth SITES:

Answer 39

Immature fibro-cartilagenous cells that are NOT layered

Question 40

What happens to a cell transplanted from a growth SITE?

Answer 40

They stop functioning (genetic mediators basically stop working)

Question 41

Are growth SITES sensitive to mechanical stimulation such as temperature and pressure?

Answer 41

YES; tension makes bone, pressure resorbs bone

Question 42

Discuss the amount of bone formed at growth sites via mechanical stimulation:

Answer 42

Amount of bone formed is minimal

Question 43

Growth SITES respond to:

Answer 43

Mechanical stimualtion

Question 44

The amount of growth that occurs at a growth SITE is:

Answer 44

Minimal

Question 45

______ are genetically programed and less affected by the environment

Answer 45

Growth CENTERs