Lecture 3 Flashcards
When is extraction of an ankylosed primary tooth recommended?
-If the primary tooth drops below the height of contour
T/F Growth is controlled both by genetic factors and environmental factors
True
What is the theory of genetic blue print model?
-The role of genetic preprogramming has long been presumed by many to have a fundamental influence in establishing basic facial pattern
How do bioelectric signals occur?
-From distortions of the crystals in the bone that can lead to the triggering of osteoblastic and osteoclastic responses
What is Wolffs law?
-Bone in a healthy person or animal will adapt to the loads under which it is placed, if loading on a particular bone increases, the bone will remodel itself over time to become stronger
What is the mechanostat theory?
-Bone growth and loss is stimulated by the local mechanical elastic deformation of bone
There is a linear relationship in a healthy body for the growth of bone between what?
-Muscle cross sectional area and bone cross sectional area
What is a growth site?
-A location at which growth occurs
What is a growth center?
-Location at which independent growth occurs regardless of the growth and development of adjacent structures
T/F The pressure created by growth at the sutures, causes the maxilla to be pushed downward and forward
False
-People used to think this was true but later discovered it was not true
If a piece of epiphyseal plate is transplanted somewhere else and it keeps growing does that make it a growth site or growth center?
-Growth center
Are sutures growth sites or growth centers?
-Growth sites
Synchondroses are growth centers or growth sites?
-Growth centers
Is the nasal septum a growth site or growth center?
-Growth center
What does growth typically refer to?
-increase in size, but it can tend to be more linked to change than anything else
T/F All of the tissue systems of the body grow at the same rate
False
-They do not grow at the same rate
What does a change in growth pattern indicate?
-Some alteration in the expected changes in body proportions
When is the peak growth for girls?
-Around 12`
When is the peak growth for boys?
-Around 14
T/F Boys will generally start growth sooner for a shorter amount of time?
- False
- Girls
What are the three cellular possibilities for growth?
- Hypertrophy
- Hyperplasia
- Cells secrete extracellular material
T/F Cartilage behaves like soft tissue
True
THe direct addition of new bone to the bones surface can and does occur through the activity of cells located where?
-Periosteum
T/F Bone is formed as a primary tissue
False
-It is never formed as a primary tissue
T/F Once bone is mineralized interstitial growth is impossible
True
The greatest period of cranial growth occurs between what age?
-Birth and 5 yrs
What serves as a major site of bone expansion during postnatal craniofacial growth?
-Sutures
For sutures to function as growth sites they need to remain in what state?
-An unossified state
What type of bones is the cranial vault made up of?
-Flat bones formed via intramembranous bone formation
What is the most complex structure of the human skeleton?
-Cranial base
What is the first region of the skull to reach adult size?
-Cranial base
How does the cranial base form?
-Endochondral ossification
What are the three pairs of cartilaginous precursors for the chondrocranium?
- Ethmoid prechordal
- Sphenoid hypophyseal
- Occipital parachordal
Histologically what do synchondroses look like?
-Two-sided epiphyseal plate
T/F Typically more bone deposition occurs on the ethmoid bone at the sphenoethmoidal synchondrosis
True
How does growth of the maxilla occur?
-Apposition of bone at the sutures by they periosteum
What direction does the maxilla grow?
-Downward and forward
What two ways accomplish the downward and forward growth of the maxilla?
- A push from behind created by cranial base growth
- By compensatory growth at the sutures in response to the displacement of the maxilla through soft tissue growth
Where is the maxilla attached?
-Anterior end of the cranial base
