week 1 Flashcards
what is growth
Anatomical invcrease in size or number
what is development
physiologic due to increase in organization, complexity, specialization at the expense of loss in potential
how does the madible change
via growth and development
- changein position and shape from translation and remodeling
what does development of the mandible lead to
higher specialization for functions of mastication and speech
how does the mandible grow
growth is upwards and backwards
- pushes the mandible forward and downward
is normal growth random
No, follows pattern
what is the gradient of growth for the body
head it full size first and feet are full size last
what is the gradient of growth for the head
cranium grows fast and first
mandible grows to correct size last
what is used to look at the growth rate of differentient tissues of the body
Scammon’s growth curves
what tissues in the body grow the fastest
Lymphoid Neural maxillary mandibular general genitals
what does gradient changes in height and weight show
Significant health isssues
when are variations in growth due to timing most evident
During adolescence
craniometry
Measuring cranial width
anthropometry
measuring cranial circumference
what are the 3D methods to image the head
CAT scans
Cone beam CT
Magnetic resonance imaging
what is interstitial growth
Growth that occurs by a combo of hyperplasia, hypertrophy, and secretion of ECM within tissues
how common is interstitial growth
Done in all soft tissues
Cartilage
how does the cranial base grow
Interstitial growth
what happens if the ECM of interstitial growth is not mineralized
growth may continue in soft tissue and cartilages
what is appositional growth
Growth that occcurs by a combo of hyperplasia, hypertrophy, secretion of ECM at the surface of bone
how does the bony surface of the crnail vault growth
Appositional growth
how does the bony surface of the maxilla and mandible growth
appositional growth
can interstitial growth occur within bone
No
can interstitial growth occur within cartialge
Yes
how can growth occur once cartialge has turned into bone
Apposition
what is endochondral growth
Bone growth within cartialge
how does endochondral growth occur
Ossification centers occur within cartialge
cartilage transformed into bone
what does endochondral ossification
Chondrocranium (ethmoid, sphenoid, basiooccipital bones)
epiphyseal plate cartialge of long bones
what is intramembranous ossification
secretion of bone matrix within/between connective tissue membranes
- no cartialge, no replacement of cartialge
what does intramembranous ossicification
Desmocranium (cranial vault, maxilla, mandible)
does the mandible arise from meckel’s cartilage
No
what does the condylar cartialge come from
Secondary cartilage (not meckel’s cartilage)
where does surface modeling happen
Occurs at the surface of growthing endochondral and intramembranous bones
does surface and internal remodeling change bone shape
Only surface does
what allows for internal remodeling
Vascular channels within bones bring osteocytes to the area
why is internal remodeling important
adapt to mechanical stress
exchange Ca and P
where does Craniofacial growth occur
Cranial vault
Cranial base
Nasomaxillary complex
Mandible
how id the cranial vault formed
from flat bones via intramembranous formation
what does periosteal activity at the cranial vault lead to
Bone modeling both at sutures and innter and outer surfaces
how does the brain case grow
Primarily by apposition of new bone at sutures
modeling of inner and outer surface of bones
how are the bones of the cranial base formed
endochondral ossification
bones of the cranial base
ethmoid
sphenoid
basi-occipital bones
what joints are found between bones of the cranial base
immovable cartilaginous synchondrosises
where does growth occur in the cranial base
Endochondral growth within synchondrosis to lengthen area of the cranial base
what connects a suture
Connective tissue
how does a suture growth
Direct ossification (appositional)
how is the nasomaxillary complex made
Intramembranous ossification
how does the growth of the nasomaxilary complex occur
Appositiona and surface modeling
how does the maxilla translate
Down and forward by apposition of bone at the circum-maxillary sutures
how is surface modeling of the maxilla done
Anterior bone is resorbed
Apposition of bone at maxillary tuberosity
Floor of nose resorbed
Apposition at the palate and alveolar process
what does surface modeling of the maxilla lead to
Palate moves downward and widens
how does the mandible growth
Endochondral growth at the condyl cargilage
rest is by apposition and modeling
where is the principle site of growth
Posterior surface of ramus and the condylar/coronoid processes
resorbed at the anterior
what is a site of growth
Location where growth occurs
what is a center of growth
Location at which independent growth occurs
how are sites and centers of growth related
Centers of growth are also sites, but not the reverse
what is the suture theory of growth
All tissues that form bone intrinsically are able to too, and Growth centers are the source of genetically controlled growth
what strucutures does the suture theory include
Sutures
Periosteum
Synchondroses
Mandibular condyl
what should that suture theory is not true
Transplantation studies
Mech pull at sututres
do we beleive in the suture theory
No, sutures and periosteum are growth sites (not centers) that react to other structures
what is the cartilage growth theory
All cartilages are growth centers
what are the growth centers for the mandible, maxilla, and cranial base due to the cartilage theory
Mandibular condyle
nasal septum cartilage
synchondroses of cranil base
what supports the cartilage theory
- Transplanted cartilage from synchondroses and nasal septum capable of growth (growth centers)
- early loss of nasal septum, results in midface deficinency
what doesn’t support the cartilage theory of growth
transplanted mandibular condyle cartilage is less growth (not a growth center)
- some reduction of growth of mandible if injured but not much
- new condyle regenerates at fracture site
what is the functional matrix theory of growth
heredity and genes plat no role in growth of Cranial facial skeletal
- growth of face occurs in response to functional needs, mediated by soft tissues near bone
- ALL bone forming tissues are merely growth sites
mandibular ankylosis
Infection to the TMJ area leads to scaring preventing growth of mandible
what is the clinical application of the functional matrix theory
- Rapid Palatal expansion leads to new bone forming
- distraction osteogenesis: tension causes bone to fill at splits
where are the holes in the functional matrix theory
not clear as to how functional needs are transmitted to the tissues of the mouth and nose
what has recent bio shown about genes involved in craniofacial growth/development
Involved in hereditary and mech modulation of craniofacial growth and development
what causes the cranium to grow
Brain (sutures and perisoteum are growth sites)
what cuses growth of cranial base
Endochondral at synchodroses (growth centers)
what causes growth of maxilla
- modeling of bone translated by soft tissues (sutures and periosteum= growth sites)
- endochondral growth at the nasal septum cartilage (growth center)
what causes growth of mandible
Endo growth at condyl with surface modeling translated via soft tissues (condyl+ peirosteum = growth sites)
what happens in adolescence
Growth spurt takes place
Fertility attained
Lots of physio and psych changes take place
what does pubery depend on
Levels of sex hormones cause changes in growth and development
what do sex hormones cuase
Accelerated genital growth
sec sex characteristics
accelerated general body growth and shrinking of lymphoid tissue
how do sex hormones affect endochondral growth
increase cartilage growth
increase transformation of cartilage to bone
how much later do males do growth spurt
1.5-2 years
how related are secondary sex characteristics to an individual on the growth curve
well related
what part of the face is growth in height related
Jaw growth
what happens at the beginning and end of male growth spirt
Beginning: growth
End: facial hair pigmented and mature voice
length of male and female growth spurt
Male:5 years
Female: 3 years
what happens at the beginning and end of gemal growth spirt
Begin: boobs
End: menarche
how do cervical vertebra change as you gro
Get more tall and concave shapped
what growth curve does the mandible grow as
General growth curve
what growth curve does teh amxilla follow
Neural growth curve
what is comparison of growth time of the mandible of width, height, and length
width stops first
Length middle
height last
what part of width does not stop before the growth spurt
Alveolar arch widen in area of molar eruption
what still grows through puberty in the face
Length
Height
why does the height of the face grow longer than the length
Verticle growth of mandible
what is the eruption sequence
Man 1st molar Max 1st molar man central inc max central in man lat inc max lat inc max 1st premol man canine man 1st premol max2nd premol man 2nd premol max caine man 2nd molar max 2nd molar man/max 3rd molar
where are permanent incisors located in relation to primary incisors
lie lingual to primary incisors
why are primary incisors separated(incisor liability)
permanent incisors are 2-3.5mm/quadrant wider
what allows larger incisors to come
Normal spacing (developmental and primate)
labial eutpion of permanent max incisors)
increased arch width
distal reposition of canines of manidble
wheree are developmental spaces found
BEtween incisors
where are primate spaces
Maxillary: mesial of canine
Mand: distal of canine
how common is spacing in children
60-70%
how do canines erupt in comparison to primary
Buccal
when will a central diastema close
in the maxillary arch, less than 2 mm with mixed dentition
what is leeway space
the difference in M-D width between primary canine/molars and perm. canine/pre-molars
where do permanent molars move into slightly
Leeway space
when should you do ortho is anterior crowding is present
just before primary 2nd molar exfoliate
mesial step molars develop into
Class I
flush terminal plane develops into what
Class II
distal step develops into what
Class II
what is the E space
The leeway space infront of the molars
what molars tend to move into the E space by moving Mesially
mandibular molars more than maxillary
what are the characteritics of normal growth
within 2 std dev of 50 percent (3-97%)
dont change percentile dramatically
