Growth and Development 25% 16Q Flashcards
which synchondroses is thought to be the driving force for skull base growth? when does it fuse?
spheno-occipital
12-15 yrs of age (SG says 15-17)
describe the type of growth that the condyle induces
regional adaptive growth
T/F: the condyle a major growth center for the mandible
False
T/F: the periosteum continues to function as an osteogenic zone throughout life
True
Enlows “V principle” says that complex bones maintain their characteristic shape by ________ on the inside of the V in the direction of growth, and __________ on the outside
deposition
resorption
what is the name of the embryonic swelling which gives rise to the tongue? (anterior 2/3)
tuberculum impar
the foramen cecum is formed during the embryological descent of the…
thyroid gland
_______ growth is the result of hyperplasia and hypertrophy in soft tissue
interstitial
___________ growth is the result of hyperplasia and hypertrophy in hard tissue
appositional
the ovum stage of fetal development occurs from:
fertilization to day 14
the embryonic period of fetal development occurs from:
week 2- week 8 (1-2mo.)
most anomalies develop during which stage of fetal development?
embryonic period (week 2-8)
the fetal stage of fetal development occurs from:
week 8- week 36
mesenchymal condensation leads to the formation of ______
bone
Meckel’s cartilage originates from which branchial arch?
1st branchial arch
Meckel’s cartilage forms 3 structures, name them :
malleus
incus
sphenomandibular ligament
T/F: Meckel’s cartilage is a precursor to the Mandible
False
In the Scammon growth curves, lymphoid tissue shows a decrease in size in the ___________ period because lymph tissues regress as
______ tissues develop
circumpubertal
genital
as seen in the Scammon growth curves, __________ tissue is the first system formed in the embryo
neural
According to Scammon growth curves, the maxillary and mandibular curves sit between the _________ and __________ growth curves
neural
general
Another name for general Scammon growth curve
Somatic
Scammon growth curves: the skeletal genital curve is inversely proportional to the __________ growth curve
lymph
In females, 50% of their growth is complete by age ___
age 6
soft tissue thickness increases more with age in: females or males?
females
Scammon curves: the facial growth curve most closely parallels the _______ curve
somatic (general)
during growth, we see two growth peaks in height, one in early infancy and one in adolescence. Which is largest?
peak velocity height (highest growth rate at any age) occurs in adolescence
in girls, peak veloticy height (PVH) happens during stage ___ of development, ____months after onset of puberty. ___ months after PVH, then end of the spurt in marked with menarche
II
12
18
in late maturing girls, peak velocity height occurs ___ - ___months before
menarche
6 - 11
in boys, peak veloticy height (PVH) happens during stage ___ of development.
12 months after their _____ ______ boys undergo puberty.
PVH happens ___ - ___months after the onset of puberty.
The one of the spurt happens ___ - ___ months after PVH
III
fat spurt
8-12 months
15-24 months
branchial arched develop at ____ week from mesodermal outpouching on both sides of developing _________
4th
pharynx
________ _________ cells enter the branchial arches and contribute to craniofacial bones and cartilages
neural crest
the tongue forms during weeks ___ - ___
4 - 8
tongue formation:
anterior ⅔ from the tuberculum impair of the ____ arch
posterior ⅓ from the cupola of the ___ and ___ arches
1st
3rd and 4th
formation of the palate begins in the ___ - ___ weeks and completes around ___ months
7th - 8th weeks
3 months
which nerve arises from the 1st branchial arch
(V3) Trigeminal
which nerve arises from the 2nd branchial arch
(VII) Facial
which nerve arises from the 3rd branchial arch
(IX) Glossopharyngeal
which nerve arises from the 4th branchial arch
(X) Vagus
superior laryngeal
which nerve arises from the 6th branchial arch
(X) Vagus
recurrent laryngeal
which muscles arise from the 1st branchial arch
Mm of mastication
which muscles arise from the 2nd branchial arch
Mm of facial expression
which muscle arises from the 3rd branchial arch
stylopharyngeus
which muscle arises from the 4th branchial arch
cricothyroid
which muscle arises from the 6th branchial arch
Mm of the larynx
(except cricothyroid)
which structures arises from the 1st branchial arch (7)
malleus
incus
maxilla
mandible
Meckel’s cartilage
temporal bone
external auditory meatus
which structures arises from the 2nd branchial arch (4)
stapes
hyoid
styloid process
Reichert’s cartilage
which structures arises from the 3rd branchial arch (3)
posterior ⅓ tongue
foramen cecum
thyroid gland
which structures arises from the 4th branchial arch (2)
thyroid cartilage
part of tongue
which structures arises from the 6th branchial arch (?)
tongue
other cartilages
at what age do the mandibular centrals erupt? maxillary?
6 mand
7 max
at what age do the mandibular laterals erupt? maxillary?
7 mand
8 max
at what age do the mandibular canines erupt? maxillary?
9 mand
11 max
at what age do the mandibular first premolars erupt? maxillary?
10 mand
10 max
at what age do the mandibular second premolars erupt? maxillary?
11 mand
11 max
at what age do the mandibular first molars erupt? maxillary?
6 mand
6 max
at what age do the mandibular second molars erupt? maxillary?
12 mand
12 max
at what age in months do the primary mandibular centrals erupt? maxillary?
6 mand
7 max
at what age in months do the primary mandibular laterals erupt? maxillary?
7 mand
9 max
at what age in months do the primary mandibular canines erupt? maxillary?
16 mand
18 max
at what age in months do the primary mandibular first molars erupt? maxillary?
12 mand
14 max
at what age in months do the primary mandibular second molars erupt? maxillary?
20 mand
24 max
Primary teeth develop in utero by week ___
6
Primary teeth calcify in utero by week ___
12-14
permanent teeth develop in utero by week ___
12
permanent teeth calcify in utero by month ___
9
Case scenario: if an 8 yo boy has a central diastema of 1.5mm, what will happen to diastema with age?
space will close when U3s erupt
neural crest cells → ectoderm → _______ (which dental structure)
enamel
neural crest cells → mesoderm → ectomesenchyme → ______ (which dental structures (4)
dentin
PDL
pulp
cementum
ectoderm gives rise to: (4)
skin
hair
nails
enamel
the enamel organ originates from the dental ______
lamina
name the 3 components of the enamel organ
enamel epithelia
enamel reticulum
ameloblasts
which permanent teeth have been calcified by birth?
mand. incisors
when do permanent teeth begin to calcify ?
by birth, month 9
In permanent molar formation, 1st molar buds develop at ___ - ___ months, 2nd molar buds develop at year ___, and 3rd molar buds develop at year ___
0 - 3 months
year 3
year 9
case scenario: in an 11 year old male, his mandibular molar are expected to erupt ____mm in 2 years and his LAFH is expected to increase ___mm per year
1.5mm
1mm
which tooth shows the greatest variation in onset of mineralization?
mandibular 5s
what is the minimum number of developmental lobes for any tooth?
4
which chromosomes play an important role in tooth development? (2 answers)
X chromosome
chromosome 4
T/F: the synchondroses undergo both endochondrial and intramembranous growth
True
fusion of the inter sphenoid synchondroses occurs when?
complete at birth
fusion of the anterior and posterior occipital synchondroses occurs when?
between age 3 & 5
fusion of the spheno-ethmoidal synchondroses occurs when?
7-8 years
fusion of the spheno-occipital synchondroses occurs when?
age 15-20
the sphenoid-occipital synchondroses is also know as the principal ______ _______
growth cartilage
the cranial base grows by ________________ growth
endochondrial
Craniofacial complex bones that grow by intramembranous (only) growth (8 types)
Parietal (2). ; Frontal (2)
Nasal (2). ; Vomer
Lacrimal (2). ; Maxilla
Palatine ; Zygomatic (2)
Craniofacial complex bones that grow by both intramembranous and endochondrial growth (5 types)
Occipital
Temporal (2)
Malleus (2)
Mandible
Sphenoid (1)
Craniofacial complex bones that grow by endochondrial (only) growth (5 types)
Ethmoid
Inferior concha (2)
Incus (2)
Stapes (2)
Hyoid
what are the facial primordia?
mainly of neural crest cells that have migrated from the cranial crest and settled.
name the 5 facial primordia
frontonasal prominence
two maxillary prominences
two mandibular prominences
what structure surrounds the primordial mouth?
stomatodeum
almost all of the CT tissues of the face are sourced from _______ _______ cells
neural crest
The frontonasal prominence gives rise to the: (3)
forehead
nose
short margin of the mouth
Of the facial structures, which form first?
lower jaw and lip
the nasal places are surrounded by:
medial and lateral nasal prominences
T/F: the nasal pit remains connected to mouth
True
Maxillary prominences grow towards each other, pushing _____ prominences medially
nasal
greatest dimension of face at birth
transverse (width)
during growth of the face, which dimensions complete first
transverse 1st
AP 2nd
Vertical 3rd
the downward and forward direction of facial growth is created by: (4)
upward and backward growth of the maxillary sutures
upward and backward growth of the mandibular condyle
vertical eruption of dentition
mesial drift of dentition
Adenoid faces are characterized by (4)
narrow transverse dimensions ( with high arched palate)
protruding teeth
incompetent lips
not obligatory mouth breathers
upper and middle part of the face are formed by what kind of growth
intramembranous and endochondrial
neurocranium and mid face are formed by what kind of growth?
sutural, endochondrial and appositional growth
what is the best genetic prototype for predicting facial growth?
same sex siblings
the tongue reach its full size at what age?
8
which profile change from adolescence to adulthood is greater? skeleton or ST?
ST
Which study proved “There is an increase in all facial dimensions in adults. The cumulative effect on the adult facial skeleton was large.”
Beherents Study (from Bolton study)
in males, which structure never stops growing
the nose
Nasomaxillary growth occurs at which locations?
the sutures and the nose
Palatal growth occurs by apposition on the _______ and ________
lingual and sutural
palatal vertical growth resorption along the __________________ and deposition on the ______________________ with resultant downward movement of palate
floor of the nose
roof of the mouth
palatal transverse growth occurs via apposition along the _____________________
midpalatal suture
the palate closes on week ___ of fetal life
12
palate is composed of what 2 bony structures
palatal process of maxilla
horizontal plate of palatine bones
T/F: Mandible shows steady growth before puberty
True
The ramus of the mandible grows ___ - ___ mm per year
1-2mm
The body of the mandible grows ___ - ___ mm per year
2-3mm
which bony structure is the smallest at birth when compared to the size of adulthood
mandible
condylar growth is ____________ and growth of the mandibular body is _______________
endochondrial
intramembranous (but appositional is major form of growth)
Late Mandibular growth in a patient with tight anterior occlusion may cause: (3)
Distal displacement of the mandible
- *Flaring of the maxillary incisors**
- *Crowding of the mandibular incisors**
when is mandibular/condylar hypoplasia most common?
early childhood
Rotational growth of the Mandible is shown by: (2)
bending of the canal
condylar neck angle
Do females have a higher rate of vertical or AP growth of the mandible?
vertical
The body of mandible lengthens by remodeling (via resorption) of the ________ _________, allowing allows for increase in mandibular corpus length.
anterior ramus
Condylar pole is 2x wider in the ____________ dimension than in the _______________ dimension
transverse > AP
mandibular growth sites:
Condylar process
posterior border of ramus
dentoalveolar process
anterior growth of the chin is caused by resorption at
B point
Mandibular growth is generally characterized by an _________ and
_________ curving growth at the condyle
upward & forward
what is the lowest tooth in the mandible at age 8?
2nd premolar
Bjork 7 signs of growth rotation
- Inclination of the condylar head
- Curvature of the mandibular canal
- Shape of inferior border of mandible
- Symphysis inclination
- Interincisal angle
- Interpremolar and intermolar angle
- Lower anterior face height
most reliable signs of aberrant eruption in maxilla
U3s ahead of 4s or 5s
most reliable signs of aberrant eruption in mandible
L7s ahead L5s
first mot common ectopically erupting teeth are ____’s, and the second is ___’s
U6’s then U3’s
Additional space for eruption of succeeding maxillary molars achieved by
downward/forward displacement of maxillary complex
appositional growth at maxillary tuberosity
Arch length space for the eruption of succeeding mandibular molars achieved by:
resorption at the anterior border of the ramus
mechanism of tooth eruption is based on proliferation of cells at the base of the _______ _______ adjacent to the dental follicle
bony crypt
The amount of eruption after the teeth come into occlusion equals the:
vertical growth of the ramus
There is equivalent eruption of upper and lower molars between the age of ___ - ___
10 - 14
Missing teeth in order of incidence
Third molars (8s)
Lower second premolars (L5s)
Lateral incisors (2s)
Tooth begins to erupt at ____ root formation
⅔
Apex closes ___ - ___ years after eruption
2 - 3
Peak incidence of dental trauma at ___ - ___ years
8 - 10
part of periosteum below growing end of root
Hammock ligament
Tooth eruption associated with all of the following, EXCEPT:
- Elongation of root
- Occlusal movement
- Mesial movement
- Growth of alveolar bone
- Resorption of deciduous tooth roots
mesial movement
The clinical presentation where centrals and laterals in but are spaced is called ____________________ and happens at ___ - ___ yrs of age
the ugly duckling stage
7 - 12
Non-syndromic tooth agenesis has been related to specific mutations of the _____ and _____ genes in humans
MSX1
PAX9
When asymptomatic non-ectopic impacted mandibular third molars are followed from a mean age of 20-24 years, ____% of the molars are expected to erupt into a normal position
33%
Mental retardation is strongly associated with _______ tooth eruption
delayed
There are ____ chromosomes in a somatic cell (including 2 sex chromosomes)
46
Meiosis reduces the number of chromosomes by half to ___
23
Name 3 conditions that show an increased prevalence of root resorption
hypothyroidism
hypoparathyroidism
Paget’s disease
________ and ________ shaped roots more likely to resorb.
blunted & pipette
T/F: Gender is a risk factor for root resorption
False
T/F: Root canal treatment is a risk factor for root resorption
False (even with trauma history)
Root resorption incidence is greatest with _______ compared to ______ injuries due to extraoral drying time.
avulsion > luxation
Incisors that are traumatically intruded in children over 6mm have only a ___% chance of 5 yr survival, while incisors intruded less than 3mm have a ___% survival rate.
50%
100%
Risk factors associated with root resorption (2)
genetics
previous trauma
a normal eruptive force is ___ - ___ gm
2-10 gm
sesamoid ossification first appears around age ___ for females and ___ for males
12.5
at puberty
after the first appearance of the sesamoid bone, there are ___ - ___ years of growth left, meaning ___ - ___% of growth remains
2 - 3 yrs
60 - 70%
Sesamoid ossification is represented by SMI ___
4
Sesamoid ossification appears in females at around age ___, when only ___ % of their growth is complete
11
33%
Sesamoid ossification appears in males at around age ___, when only ___ % of their growth is complete
12
29%
Sesamoid ossifies ___ year prior (at start of puberty) to the pubertal maximum growth spurt when the PVH is reached: in female this is at age ___, in males this is at age ___
1
12
13
SMI 6 is represented by___ capping and means that ___% of growth remains
MP3
50%
SMI 7 is represented by___ capping and means that ___% of growth remains
MP5
25%
the growth spurt happens between SMI stages ___ and ___
6 & 7
the SMI stage signaling the end of the growth spurt is the SMI ___ when you see __________ of epiphysis and diaphysis of distal phalanx of ___ finger
SMI8
fusion
3rd
the primary growth center of a long bone is the
epiphysis
the shaft of a long bone is called its
diaphysis
carpals are in the ______
__________ are in the hand and
___________ and in the fingers
wrist
metacarpals
phalanges
CVM II is represented by concavities at the lower borders of both ___ and ___ are present. Bodies of C3 and C4 may be trapezoid or rectangular horizontal in shape.
C2 and C3
Peak Mn growth occurs one year after CBM stage ___
II
CVM stage ___ represents the ideal stage to begin functional jaw orthopedics because peak mandibular growth occurs 1 year later
II
Transposition happens in 1/___ ortho cases or <1% of the population
1/300
major causes of transposition (4)
- Genetics
- exchange of developing tooth buds
- altered eruption paths
- retained primary teeth are causes
