- becomes the ameloblast, makes enamel

Exam 2 Flashcards by Taya Johnson

What controls the way the tooth shape is formed?

dental papilla

How well did you know this?

Not at all

Perfectly

what is the root number controlled by?

Hertwigs epithelial root sheath and epithelial diaphragm

How well did you know this?

Not at all

Perfectly

the dentin matrix causes nuclei of pre-ameloblasts to what

polarize (move to the top of the cell) to become an ameloblast

How well did you know this?

Not at all

Perfectly

Inner enamel epithelium become taller to create what?

pre-ameloblast

How well did you know this?

Not at all

Perfectly

mineralization

laying down/ depositing of HA

How well did you know this?

Not at all

Perfectly

maturation

where crystals grow in length (HA) over time

How well did you know this?

Not at all

Perfectly

enamel comes from what germ layers

ectoderm

How well did you know this?

Not at all

Perfectly

dentin, pulp, cementum, PDL, alveolar bone come from what layer?

mesoderm

How well did you know this?

Not at all

Perfectly

in the crown, which one forms first?

dentin

How well did you know this?

Not at all

Perfectly

What process does enamel form from?

Tomes process

How well did you know this?

Not at all

Perfectly

What process does dentin form from?

Odontoblastic process.
- mineralizes HA into the dentin matrix

How well did you know this?

Not at all

Perfectly

Role of IEE

becomes the ameloblast, makes enamel

How well did you know this?

Not at all

Perfectly

what are the abnormalities of enamel?

enamel lamella
hypoplastic enamel
enamel tuft
enamel spindle

How well did you know this?

Not at all

Perfectly

What is enamel lamella

cracks in enamel

How well did you know this?

Not at all

Perfectly

what is hypoplastic enamel

thin enamel
think of mean girls and the plastics

How well did you know this?

Not at all

Perfectly

what are enamel tufts

hypocalcfied enamel at the DEJ

How well did you know this?

Not at all

Perfectly

what are enamel spindles

the odontoblastic process trapped in enamel

How well did you know this?

Not at all

Perfectly

imbrication lines

seen clinically

How well did you know this?

Not at all

Perfectly

Striae of Retzius

under a microscope
- brown in color

How well did you know this?

Not at all

Perfectly

How many increments does enamel grow each day?

4 um per 4 days

How well did you know this?

Not at all

Perfectly

What is the last layer laid down when the ameloblasts reach the OEE?

Nasmyths membrane
aka: primary enamel cuticle

How well did you know this?

Not at all

Perfectly

Nasmyths membrane is made when?

when enamel stops forming
then the membrane is laid down

How well did you know this?

Not at all

Perfectly

What is the reduced enamel epithelium made up of?

OEE + ameloblasts

How well did you know this?

Not at all

Perfectly

What is the united enamel epithelium made of?

REE + oral enamel epithelium

How well did you know this?

Not at all

Perfectly

ratio of enamel

96/4

ratio of dentin

70/30

ratio of cementum

50/50

ratio of bone

65/35

What are characteristics of the enamel rod?

- key hole shaped - 96% inorganic - runs from DEJ to surface - 3-4 ameloblasts made ONE rod - held together by inner rod substance

rod sheath characteristics

- 4% organic - fibrous - covers enamel rod

Inner rod substance

- holds things together - structure

what is the orientation of HA crystals on the head of the rod?

laid down longitudinally

what is the orientation of HA crystals on the neck of the rod?

laid down 60 degrees off the head

how many ameloblasts make one rod?

3-4

What are the 3 zones of dentin>

- tubule - peritubular - intertubular

What is the dental tubule?

- opening that runs from DEJ and CEJ to the pulp

what zone of dentin is related to the odontoblastic process?

dental tubules

what is peritubular dentin?

- immediately surrounds the tubule MOST CALCIFIED

what is intertubular dentin?

- bulk of the dentin

what are the 3 types/phases of dentin formation

- primary - secondary - teritiary

when does primary dentin start and end

starts at tooth formation ends prior to eruption

when does secondary dentin form?

starts with eruption ends with contact of opposing tooth

when does tertiary dentin form?

starts with contact and beyond - dense and unorganized

how does tertiary and reparative dentin form?

- occlusal, chemical, mechanical trauma

occlusal trauma

biting, chewing, grinding

mechanical trauma

drill and laser

chemical trauma

acids from bacterial products (caries)

what does the pulp sense

ONLY pain

what does the PDL sense?

- pain - pressure - temperature - touch

what are the types of pulp stones?

- true and false - attached - embedded - free

Free pulp stone

- floating there, not attached to dentin

attached stone

attached to the dentin wall

embedded stone

attached and covered by dentin

true pulp stone

VERY RARE - odontoblast ball of dentin made from ^^

false pulp stone

- onion looking - dead cells surrounded by calcium and phosphate - most common

how do pulp stones show up on radiographs

radiopaque

what is the cervical loop

- where the IEE and OEE meet - rapidly divides and grows vertical

Hertwigs epithelial root sheath

- part that grows vertically - meets at the furcation with the epithelial diaphragm

whats the epithelial diaphragm

- horizontal growth - meets with HERS at the furcation

what does the epithelial diaphragm and HERS determine?

the amount of roots

Hypercementosis

- on lower portion of root (1/3) - on cellular cementum - can grow more cementum as needed due to trauma

cellular cementum

- apical 1/3 of root

acellular cementum

- coronal 2/3 of root - doesn't respond to trauma or MAKE MORE

how often does enamel and cementum meet?

-50-70%

how often does enamel and cementum overlap

7-14%

how often does enamel and cementum have a gap

10-40%

What is the rests of malassez

HERS broke up from dentin and moved away then changed its name and it is in the PDL space now

what is the cortical plate?

- buccal and lingual - not seen on radiographs - compact bone

what is the cribriform plate (socket, alveolar bone proper)

- seen on radiographs as lamina dura - thickened bone = bundle bone from the sac - always remodeling

What is spongy bone?

Aka cancelous Can see on rads. Bone marrow

Rests of Malassez

Portions of the root sheath that may remain in the periodontal space. Was once the Hertwig’s Epithelial tooth sheath May form periodontal cysts

Cortical plate

Buccal/Lingual Not on rads Compact bone

Cribriform plate (socket, alveolar bone proper)

Rods= Lamina dura Thickened bone= bundle bone from sac Always remodeling

Lamina dura

the dense, thin layer of bone that lines the tooth socket, visible on dental X-rays as a white line. It acts as the attachment site for the periodontal ligaments, which hold the tooth in place

Bundle bone

Thickened bone

Cancellous bone

AKA spongy Bone- yes on rads, and compact bone

Alveolar Crest

Indication of periodontalntal health

Sharpeys fibers

PDL segment inside bone and cementum

All of the periodontal ligament names

Horizontal, Oblique, Apical, Intradicular, and alveolar crest

Causes of a retained primary tooth

Stuck, or kept due to no permanent tooth

Eruptive phase

When tooth is erupting

Pre Eruptive phase

Before eruption

Post Eruptive phase

Phase after the tooth has erupted

Spatial movement

Bone below is pushing it up

Eccentric Movement(off-center growth)

Balloon one

Medial drift

Post eruption

Supraeruption

Post eruption

Exfoliate

Natural comes out

The orientation that permanent teeth erupt to primary teeth

Anterior teeth erupt into the oral cavity lingually Molars are directly below

Gubernacular cord

Comes from dental sac/follicle Develops into the Gubernacular canal

Exam 2 Flashcards

(90 cards)