odontogenesis Flashcards
two basic tissues that arise from the ectoderm primary germ layer involved in tooth development:
epithelium and mesenchyme
odontogenesis begins in the ____ embryonic week
6th
epithelial stages of odontogenesis
- epithelial dental lamina stage
- epithelial bud
- epithelial cap
- epithelial bell
3 parts of the tooth germ
- enamel organ (bell): epithelium
- dental papilla: mesenchyme
- dental follicle: mesenchyme
facial band is called the ____
vestibular lamina
lingual band is called the _____
primary dental lamina
cell death will occur in the center of the vestibular lamina, leaving a space known as the _____
vestibule
cells arising from the dental laminae become the _____ part of a ____
odontogenic epithelial; tooth germ
appearance times for epithelial buds of primary central incisors and second molars
central incisors: 6 weeks in utero
second molars: 8 weeks in utero
appearance times for epithelial buds of permanent central incisiors, 1st/2nd/3rd molars:
first molar: 4 months in utero
1st molar: 5 months in utero
second molar: 10 months postnatally
third molar: 5 years postnatally
a total of ____ epithelial buds arise from the ____ of each arch
16; primary dental lamina
10 primary teeth and 6 permanent molars
each primary tooth also has its own ____ that arises from ____ of the primary dental lamina
secondary dental lamina; lingual side
concentration of epithelial cells of cap that is a signaling center
enamel knot
what does the enamel knot determine?
whether the tooth will become an anterior or posterior tooth
at the bell stage, the epithelium is arranged in ____ distinct cell layers
4
4 distinct epithelial cell layers of the enamel organ
- inner epithelial layer
- stratum intermedium epithelial layer
- stellate reticulum epithelial layer
- outer epithelial layer
secondary dental lamina is ____ to the primary tooth germ; ____ secondary lamina arise in each arch, one for each secondary tooth
lingual; ten
secondary dental lamina arise from the _____, NOT the oral epithelium
primary dental lamina
the enamel organ is composed of:
epithelial enamel organ + closely associated ectomesenchyme
3 distinct parts of the enamel organ
- enamel organ (epithelium- avascular)
- dental papilla (ectomesenchyme- vascular)
- dental follicle (ectomesenchyme- vascular)
inner epithelial cells differentiate into ____- specialized epithelial cells
ameloblasts
after formation of enamel is complete, ameloblasts, along with other layers of the enamel organ, come together over the surface of the enamel as a ____ structure called _____
protective; reduced enamel epithelium (it is a stratified epithelial layer)
undifferentiated cells (stem cells) of the dental papilla become:
odontoblasts, fibroblasts (most numerous), and reserve cells
the dental papilla ultimately becomes the _____
pulp tissue of the tooth
the stem cells of the dental follicle become:
cementoblasts, fibroblasts (most numerous), osteoblasts, and reserve cells
the dental follicle ultimately becomes the _____
periodontal ligament of the periodontium
the enamel organ is attached to both mesenchymal parts of the tooth germ by a _____
basal lamina
the light, acellular layer between odontoblasts and ameloblasts is the site of the future _____
dentinoenamel junction (DEJ)
the rim of the epithelial bell (enamel organ) where inner and outer cell layers merge or meet
cervical loop
the double epithelial layer of the cervical loop is called ______
Hertwig’s epithelial root sheath
2 main functions of the root sheath
- determines root dentin outline
2. determines number of root canals of tooth
the pulp is formed from what part of the tooth germ and what two formative (blast) cell types arose from its stem cells?
dental papilla
odontoblasts and fibroblasts
the periodontal ligament is formed from what part of the tooth germ and what 3 formative (blast) cell types arose from its stem cells?
dental follicle
fibroblasts, cementoblasts, and osteoblasts
