oral histology exam 2

Odontogenesis

The process of tooth development from initiation to maturation

when tensile stress is perpendicular to rod

when does enamel fracture occur

lines of retzius

identify A (lines going up)

Initiation, Proliferation, Morphogenesis, Cytodifferentiation, Apposition, and Maturation.

Tooth Developmental processes

initiation

thickening of dental lamina at specific sites in dental arch

bud, cap, bell, crown

Tooth development stages

Enamel organ

A cap-like structure formed during the cap stage that contributes to enamel formation.

Dental papilla

Condensed ECTOMESENCHYME that forms during the cap stage, contributing to the formation of DENTIN and PULP.

Dental follicle

ECTOMESENCHYME surrounding the dental papilla that contributes to the formation of the periodontal ligament and cementum.

Cap Stage

phase in tooth development where the enamel organ, dental papilla, and dental follicle are formed.

Enamel Knot

A signaling center that regulates the growth and shape of the tooth during development.

Tooth agenesis

A condition where one or more teeth fail to develop due to genetic mutations.

Cervical loop

area where the inner and outer enamel epithelium meet, allowing for ongoing enamel production and root development

dental lamina breaks up, downward proliferation of cervical loop, differential growth of IEE (inner enamel epithelium)

what occurs during bell stage

bell stage

stage of tooth development characterized by the differentiation of the inner enamel epithelium into ameloblasts and the dental papilla into odontoblasts.

Hyperdontia

A condition characterized by the presence of supernumerary teeth, mutations in signaling molecules (Wnt, FGF, Shh) BEFORE BUD stage

Hypodontia

A condition resulting in a reduced number of teeth due to developmental issues.

Oral epithelium

The epithelial layer involved in initiating the formation and development of teeth.

dentin

what does the ectomesynchyme form during odontogenesis

enamel

what does oral ectoderm form during odontogenesis

directs epithelium to form specific tooth

role of MESENCHYME in CAP and BELL stages

initiate tooth formation in mesenchyme

role of EPITHELIUM BEFORE bud stage

inner enamel epithelium

Identify the tissue layer labeled “X”

dental papilla

Identify the tissue layer labeled “Y”

cytodifferentition

What developmental process will
developmental process tissue “X” undergoes in the bell stage to define the future shape of the crown
and cusp development?

stratum intermedium

Identify the cells present in the tissue layer marked “x”

ameloblast

Identify the cells present in the tissue layer marked “y”

preameloblasts

Identify the cells present in the tissue layer marked “z”

predentin

Identify the tissue marked by the * and stained light pink.

globular dentin/primary dentin

Identify the tissue marked with an “X”

mineralization (globular)

Describe the developmental process occuring at X

enamel

what type of tissue is this picture

rods at different angles

How does the structure pictured in box (i) differ
from that in box (ii)?

strength (compression mostly)

What is the functional significance of the structural difference between rods in i and ii?

hunter-schreger

What is the name of the enamel structure shown
in this photo?

between interrod and rods

weak point of enamel

Y less mature and has more amelogenin

how is the process at Y different from that at X

higher fracture toughness, higher tensile strength, lower stiffness, lower compressive strength

biomechanical properties of dentin compared to enamel

higher compressive strength, lower tensile strength

biomechanical properties of enamel compared to dentin

dentin has collagen

how does the composition of dentin relative to enamel corresponds with higher fracture toughness and lower stiffness

bud stage

what stage

ectomesenchyme

identify cell at C

dental lamina

identify A

bud

Identify B

cap

what stage

inner enamel epithelium

what is i

stellate reticulum

what is sr

enamel knot

where do cusps come from during this. stage

cervical loops

what are the black arrows pointing at

bell

what stage

enamel knot

Identify Y

thinning dental lamina connecting to oral epithelium

identify X

cytodifferentiation

what developmental process is occuring at this stage

dentin, predentin, odontoblast, pulp

what are the layers from top to bottom

peritubular/intratubular

what type of dentin is immediately around dentinal tubules

intertubular dentin

what. type of dentin is between dentinal tubules

peritubular is hypermineralized with less collagen

what is the difference in composition between peritubular and intertubular dentin

dentinoenamel junction

what space is shown here

surface area for connection between enamel and dentin

what is the role of this space

early cap

what stage

ectomesenchyme/dental follicle

what cells are present at A

primary epithelial band/oral epithelium

what layer is at B

inner enamel epithelium

identify X

dental papilla

Identify Y

no

is there any apposition of dental material at this point

innerr enamel epithelium

which layer in cap stage generate enamel in the bell stage

increases fracture toughness and tensile strength

how does high density of collagen fibrils organized perpendicular to dentin tubules affect the material properties of dentin

ectoderm

what embryonic tissue is DENTAL LAMINA derived from

neural crest derived from ectomesenchyme

what embryonic tissue are ODONTOBLASTS derived from

ectoderm

where is STELLATE RETICULUM derived from

neural crest cells

where is the DENTAL FOLLICLE derived from

ectoderm

where is REDUCED ENAMEL EPITHELIUM derived from

dental lamina and ectomesenchyme

what is proliferating in the bud stage

enamel epithelia and dental papilla

what is proliferating in the cap stage

cervical loop and dental papilla

what is proliferating in the bell stage

ectomesenchyme

where is the DENTAL PAPILLA derived from

enamel organ and dental papilla

morphogenesis in the cap stage

cervical loop and dental papilla

morphogenesis in the bell stage

late cap/early bell

what stage

bell stage

what stage

bell stage

what stage

rapid hypertrophy, polarized nucleus, increased organelles, numerous odontoblastic processes

characteristics of odontoblasts

mantle dentin

initial dentin secreted by odontoblasts

large collagen fibrils and matrix vesicles involved in mineralization

components of mantle dentin

fine diameter collagen fibrils and lipid

components of primary dentin

predentin

organic material layer secreted by odontoblasts before mineralization, mainly of collagen

dense meshwork perpendicular to tubules

how do collagen fibrils organize in dentin

globular calcification

mineralization of primary dentin through intracellular deposition of calcium and phosphate within predentin.

calcospherites

small spherical structures formed during the mineralization process in dentin, contributing to the globular calcification of primary dentin.

interglobular dentin/ hypomineralized matrix

What is A

calcospherite

what is B

Mineralization front

what is A

predentin

what is B

Odontoblasts

what is C

dental pulp

what is D

tomes granular layer

hypomineralized dentin in the root

collagen fibrils perpendicular to dental tuble

what contributes to the high tensile strength and fracture resistance of dentin

secondary dentin

Identify A

primary dentin

Identify B

secondary dentin

forms once the tooth is in occlusions and includes straighter tubules