PALM 309: Quiz 6

The periodontium

3 tissues that hold the tooth in position

Alveolar bone proper

bone nearest to the tooth, studded w little holes where PDL fibers insert

Supporting alveolar bone

around alveolar bone proper, no PDL fibers

Resorbtion

lost tooth with no force applied to bone that surrounds it

located in the tooth root outside the dentin

Cementum

Cementoenamel junction

cementum and enamel meet

cementoblasts

risen from mesenchyme surrounding developing tooth

cementum contains 50% of what kind of minerals?

hydroxyapatite crystals

Cementum contains about 50% of what organic materials?

collagen type 1 fibers

cementum is very similar to what?

bone

When is cementum laid down?

after the dentin in the root forms

Cementoblasts that are surrounded by cementum located in lacunae are called?

cementocytes

Contains cementocytes and is found at the root apex

cellular cementum

does not contain cementocytes and is located near the crown

acellular cementum

Layer of cementoblasts located between cementum and PDL

regenerative cementum

the PDL contains

collagen type 1 and CT cells (fibroblasts, plasma cells, macrophages, and mast cells)

insert in cementum and the alveolar bone

principal fiber group

located nearest the crown, insert into acellular cementum (top rim of alveolar bone proper)

Alveolar crest fibers

below the alveolar crest fibers, extend horizontally between the cementum and alveolar bone

horizontal fibers

largest group of PDL, run obliquely between cementum and alveolar bone

oblique fibers

located at the root apex, extend between cementum and alveolar bone

apical fibers

only found in multiroot teeth, extend between the alveolar bone and cementum at the bifurcation

interradicular fibers

insert into cementum OR alveolar bone OR don’t insert into either bone or cementum

gingival fiber group

located nearest the crown, extend between cementum of adjacent teeth

transseptal fibers

extend between the cementum near crown to gingiva

dentogingival fibers

Extend between the alveolar bone and the gingiva

alveologingival fibers

around the tooth and help keep attached gingiva attached to the tooth

circular fibers

Acts as a barrier and prevents leakage of material into PDL

dentogingival junction

the free gingiva is lined by what?

sulcular epithelium

the epithelium that attaches the attached gingiva to the tooth enamel is called?

junctional epithelium

What can cause the junctional epithelium to detach from the enamel?

infection, poor oral hygiene, and aging

Where is the black arrow pointing to?

tooth pulp

CT core of the tooth with all typical CT cells, very vascular with many nerves

pulp cavity

located in the pulp, forming a layer adjacent to the dentin

odontoblast cell bodies

beneath the odontoblasts is an area called the ___ which has very few cells

cell free zone

beneath the cell-gree zone with many cells

cell rich zone

located in the cell rich zone and extends into the cell-free zone

subodontoblast nerve plexus (Raschkow’s plexus)

abnormal accumulations of dentin or minerals that form as we age

denticles (pulp stones)

denticles that are made of dentin

true denticles

denticles that are more common and made of mineral accumulations

false denticles

abnormal accumulations of cementum

cementicles

when a tooth is lost, there is no force applied to the opposite tooth so an excess of cementum will be laid down in the opposing tooth

hypercementosis

cementum attaches directly to alveolar bone with no PDL between

Ankylosis

ID the region

cementoenamel junction

2. ID the tissue

acellular cementum

3. ID the tissue

Cellular cementum

ID the cells (top arrow)

odontoblasts

ID the region (middle arrow)

pulp cell-free zone

ID the region (bottom arrow)

pulp cell-rich zone

ID the black fibers at the point

sub-odontoblast nerve plexus

ID the fibers (bottom left arrow)

horizontal

ID the fibers (top Left arrow)

Transseptal fibers

ID the fibers (right arrow)

dintogingival fibers

ID the fibers

alveolar crest

ID the fibers

Oblique fibers

ID the fibers

interradicular fibers

ID the fibers

apical fibers

ID the fibers (top right arrow)

alveolar crest fibers

ID the fibers (bottom right arrow)

horizontal fibers

ectoderm, endoderm, and mesoderm

3 primitive germ layers

Superficial layer that gives rise to the skin, oral cavity, lining, enamel and neuroectoderm

ectoderm

gives rise to components of CNS and PNS

Neuroectoderm

Gives rise to CT, muscle, circulatory system, lymphoid, organs, kidney, most of reproductive system and most of the tooth

mesoderm (mesenchyme)

gives rise to the lining of the GI tract and most digestive organs

Endoderm

loosely arranged star-shaped cells

stellate reticulum

ID the enamel organ stage

bud stage

ID the stage

cap stage

ID the stage

bell stage

ID the cell layer (bottom left arrow)

inner enamel epithelium

ID the cell layer (top left arrow)

outer enamel epithelium

Id the cell layer (top right arrow)

stellate reticulum

Id the cell layer (bottom right arrow)

stratum intermedium

Id the cell region (top arrow)

Dental follicle

ID the cell region (bottom arrow)

Dental papilla

ID the structure

epithelial root sheath

ID the structure

epithelial diaphragm

What part of the alveolar bone do the PDL fibers insert into?

The alveolar bone proper.

What are 2 causes of alveolar bone resorption?

Loss of opposing tooth (no force applied) AND loss of PDL fibers (increased direct force on bone).

Where is acellular cementum located?

Closest to the tooth crown.

What are the functions of PDL fibroblasts?

Synthesize and resorb PDL fibers AND have contractile properties.

What 2 tissues do the PDL fibers of the principal fiber group insert into?

Alveolar bone and cementum.

What is the largest group of PDL fibers?

Oblique fiber group.

What do the PDL transeptal fibers insert into?

Cementum between adjacent teeth.

Where are the interradicular PDL fibers located?

Only in multirooted teeth; run from cementum to alveolar bone at root bifurcation.

What is a long junctional epithelial attachment?

Junctional epithelium attaches to cementum instead of enamel, causing loss of PDL space.

What is the subodontoblast nerve plexus?

A plexus of nerves in the cell-rich zone of pulp; fibers extend into dentin tubules.

What do you call an abnormal accumulation of minerals embedded in dentin?

Embedded FALSE denticle.

What can cause hypercementosis?

Loss of opposing tooth leading to excess cementum buildup.

What embryonic tissue gives rise to the gut tube lining?

Endoderm.

What part of the tooth does ectoderm give rise to?

Enamel (via enamel organ).

What embryonic cell layer gives rise to ameloblasts?

Inner enamel epithelium.

What tissue gives rise to odontoblasts?

Dental papilla mesenchyme.

What tissues does the dental follicle give rise to?

Alveolar bone, PDL, cementum.

How does the vestibule form?

Vestibular lamina proliferates, then central cells degenerate creating space between mucosa.

What 2 cell layers form the epithelial root sheath?

Inner and outer enamel epithelium.

What tooth tissue would not form if the epithelial root sheath didn’t break down?

Cementum would not form.

What type of secretory cell is found arranged in acini in salivary glands?

Serous secretory cells.