EX1; Odontogenesis Flashcards
*The formation of tooth tissue from stem cells originates in which germ layer
ectoderm
When does odontogenesis begin
the 6th embryonic week
What are the two basic tissues that arise from the ectoderm germ layer involved with tooth development
epithelium and mesenchyme
This is the formation of dentin
dentinogenesis
This is the formation of enamel
amelogenesis
This is the formation of cementum
cementogenesis
What is the order in which tooth tissue from
dentin
enamel
cementum
What are the epithelial stages
epithelial dental lamina
epithelial bud
epithelial cap
epithelial bell (organ)
What does the epithelial tissue develop within
a mesenchymal tissue environment
What is the tooth germ stage
odontogenic epithelial and mesenchymal tissue combine inducing specificity to become the formative cells or dentin, enamel, cementum, and pulp
*What are the three parts of the tooth germ
enamel bell (organ)
dental papilla
dental follicle
*What tissues make up the parts of the tooth germ
enamel bell (organ) = epithelium dental papilla and follicle = mesenchyme
During which week do the vestibular and primary dental lamina from
6th embryonic week
Which arch is a half a week behind the other in terms of development
maxillary is a 1/2 week behind the mandible
This invagination of epithelium descending into the mesenchyme appears along the facial aspect
vestibular lamina
This invagination of epithelium descending into the mesenchyme appears along the lingual aspect
primary dental papilla
True or False
Upon development, the vestibular and primary dental lamina continue posteriorly within the mesenchyme as continuous epithelial bands
True
What occurs in the center to the vestibular lamina
cell death; leaving the space as the vestibule
What do cells arising from the primary dental lamina (primary and secondary) become
odontogenic epithelial part of a tooth germ
Cells at the deep end of the primary dental lamina where a tooth is destined to be will develop into what
epithelial “knobs” or epithelial bud
Each epithelial bud is surrounded by what
mesenchymal tissue
When do the primary buds of central incisors form
6 weeks in utero
When do primary buds of second molars form
8 weeks in utero
When do permanent buds of first molars form
4 months in utero
When do permanent buds of central incisors form
5 months in utero
When do permanent buds of second molars form
10 months postnatally
When do permanent buds of third molars form
5 years postnatally
A total of how many epithelial buds arise from the primary dental lamina
16; 10 primary teeth and 6 permanent molars
On which side of the primary dental lamina does the secondary dental lamina arise
lingual
What specific structure is located in the epithelial cap
enamel knot
What is the purpose of the enamel knot
it is a concentration of epithelial cells that is the signaling center determining if the tooth will develop into an anterior or posterior tooth
What does the epithelium arrange into during the bell (organ) stage
4 distinct cell layers given names according to position within the bell and the cell morphology
What are the four distinct epithelial cell layers of the enamel organ
inner epithelial layer
stratum intermedium
stellate reticulum
outer epithelial layer
Where does the secondary dental lamina arise from
primary dental lamina (NOT the oral epithelium)
This is an epithelial enamel organ and a closely associated ectomesenchymal tissue that is continuous from around the epithelium to within the epithelium
tooth germ
*What does the inner epithelial cells differentiate into
ameloblasts
After the formulation of enamel, the ameloblasts along with other layers of the enamel organ come together over the surface of the enamel as what
a protective structure; reduced enamel epithelium
*What do the undifferentiated (stem) cells of the dental papilla become
odontoblasts
fibroblasts
reserve cells
What tissue does the dental papilla become
pulp
*What do the undifferentiated (stem) cells of the dental follicle become
cementoblasts
fibroblasts
osteoblasts
reserve cells
What tissue does the dental follicle become
periodontal ligament of the periodontium
The enamel organ is attached to both mesenchymal parts of the tooth germ via what
a basal lamina
What occurs at the cervical loop of the enamel organ
where the inner and outer cell layers merge
When the inner and outer epithelial layers merge at the cervical loop, they form what
a double epithelial layer celled Hertwigs epithelial root sheath
What is the function of Hertwig’s epithelial root sheath
determines root dentin outline
determines number of root canals of tooth
What parts of the tooth germ are avascular or vascular
avascular = enamel organ vascular = dental papilla and follicle
