Teeth Flashcards
tooth root
in part of the jaw called the alveolar ridge
portion embeded in the bone
alveolar ridge
part of the jaw where the tooth root is located
Tooth socket
alveolus
crown of the tooth
projects into the oral cavity
Enamel
- highly mineralized
- covers crown
- hard
- translucent
Enamel contains
<1% organic
96-98% hydroxyapatite
What creates enamel?
ameloblasts
come from enamel organ
When do ameloblast degenerate?
after the tooth erupts
can’t replace enamel
Tome’s Process
apical end of ameloblast
microtuble and secretory vesicles
Enamel mineralization is _______________
non-uniform
What is the shape of enamel rods/ prisms?
hexagonal
interprismatic material
- between the enamel rods
- less mineralized
Enamel rods extend from ameloblasts at
enamel surface to dentio-enaml junction
What secretes pre-dentine?
odontoblast
of dental pailla
Dentin
- bulk of the tooth
- less mineralized
Dentin has_________ hydroxyapatite
70-80%
Dentine is chemically similar to
Bone
What plays a key role in the mineralization of Dentine matrix?
matrix vacuoles (Ca2+ and PO4-)
What are in matrix vaculoes?
Ca2+ and PO4-
Dental tubules
- How dentine is arranged
- parallel tubes radiating form the pulp cavity
Tome’s process
long rod like cytoplasmic process of odontoblasts
in dentine tubules
Dentine also contains
- type 1 collagen
- GAGs
Pulp cavity contains
senrory nerves and blood vessels
support structures
Dentine is innervated by
myelinated nerves
What is the origin of dental pulp
mesodermal
Dental pulp contains
- stellate fibroblasts
- reticular fibers
- collagen
- ground substance
Dental pulp is
richly supplied by capillaries and artioles
the capillaries and artioles that supply the dental pulp run with
the periodontal ligament
What covers the outer layer of the root?
thin layer of cementum
cementum
amorphous, collagen-based, calcified tissue
cementum is similar structural and functionally to what?
osteoblast
Cementum is ________ hyrdroxyapapitite
45-50%
similar to bone
What makes cementum?
cementoblasts
What do cementoblast mature into?
cementocytes
cellular cementum (CC)
What is the growth of cementum?
appostiional growth
* cementocytes lie against periodontal ligament and produce new
gingiva
covers the upper alveolar ridge
masticory oral mucosa
neck of tooth
region between the tooth root and crown
Attached Gingiva
covers upper alveolar bone
Free Gingiva
- froms cuff
- neck of the tooth
Gingival sulcus
crevice
Space between free gingiva and crown
Crevical Epithelium
- very thin (2-3 cells)
- easily breached by bacteria
What is the tissue that surround and support the tooth?
Periodontium
Periodontium includes
- eputhelium
- cementium
- periodontal ligament
- alveloar bone
Sharpeys fibers run at
oblique angle
support tooth in socket
What achors the the cementum to the bone?
Sharpey’s fibers
allows for slight movement
Clusters of epitheila cells within the periodontal ligament
vestigial epithelial rests (of Malassez)
Tooth is formed between
layer of epithelial cells
- ameloblast of enamel organ
- odontoblast of dental papilla
What is the origin of enamel
ectodermal
Within the tooth what is mesodermal derived?
- dentin
- cementum
- pulp
- periodontal ligament
When is the teeth start to form in the fetus?
about week 6
dental lamina
form the postion of the future jaw
What are the stages of Odntogenesis?
- Cap
- early bell
- late bell
the interal enamel epithelium differeniates into
a layer of ameloblasts
Mesenchyme condense to form
dental paillae
Permanent tooth arise from
side growth of pf dental lamina
What portion of the developing ectodermal swelling forms the enamel organs?
superfical
What portion of the developing ectodermal swelling forms the dental papilla?
the deep portion
What is the central portion of the enamel organ called?
central stellate epithelium
What is the outer layer of the enamel?
cubodial/columnar epithelium
The internal enamel epithelium becomes the
ameloblasts
Straum intermedium
- 2-3 cells thick
- associated with layer of ameloblasts
What does the permanent tooth (bud) arise from?
side of the dental lamina
during the ealry bell stage
enamel organ is intially
cup-shaped
cells of the enaml organ progressively differentiate and become
stellate reticulum
external enamel epithelium
cells lining outer surface of enamel organ
internal enamel epithelium
cells linining the concave surface of enamel organ
cells lining convex surface of dental papilla
develop into odontoblasts
internal enamel epithelium differentiate into
ameloblasts
Amelogenesis
enamel formation
by ameloblasts
Dentinogenesis
dentin formation
by odontoblast
What induces the differentiation of odontoblasts?
the devleopment of ameloblasts
what iniates tooth formation?
depostion of organic pre-dentine by odontoblast
later calcified into dentine
What triggers ameloblast to deposit enamel?
calcification of dentin matrix
secondarily induces enamel production by ameloblast
odontoblast have
odontoblast processes
odontoblast processes are
embed in the dentine matrix
odontoblast processes form
dentine tubules
what are enamel rods seperated by
interprismatic material
less mineralized
At the time of eruption what degenerates?
enamel organ and ameloblasts
________ shinks and become dental pulp
dental papilla
Hertwig’s root sheath is located
at the cervical loop of the enamel organ
Hertwig’s root sheath triggers
formation of dentin in the root
How does Hertwig’s root sheath trigger formation of dentin in the roo
the differentiation of odontoblast from the dental papilla
When Hertwig’s root sheath disintergrates some parts become
epitheial cell rests
After the tooth formation is complete what is still produced
small amounts of 2’ dentin
The outer rim of the enamel organ is known as
epitheial sheath of hertwig
epitheial sheath of hertwig funciton
determines the cross-sectional outline of the tooth
Dental Follicle becomes
ar large portion of the periodontal ligament
What is something unique about the permanent molar?
the dental lamin proliferates on its own
when do tooth development begin
6th week of fetal development
What is the eruption time of the deiduous teeth?
6 - 30 months
what is the formula for deciduous teeth
2I 1C 2M
When do permanent teeth erupt?
6- 12 years of age
Tertracycline giving during devleopment
can cause teeth to be yellow in color
Human Dental Formula
I 2/2 C1/1 P2/2 M/3/3
Orthiodontia works due to
osteoblast and osteoclast activity in the aveolus
Dental Caries
acid erode and bacteria eat away
Fluriode helps to
harden enamel and kill bacteria
Periodontal Disease is caused by
accumulation of plaque in gingival sulcus
gingivitis
inflamation of gums
where does the tooth numbering start?
on the upper right