Dentin 1

Question 1

Composition

Answer 1

70- inorganic
20- organic
10- water
HA crystals in flattened rectangular plates 60-70 nm long, 20-30 nm wide, 3-4 nm thick
slightly harder than bone
mesenchymal origin

Question 2

Organic components of dentine

Answer 2

90% collagen (mostly 1 and a little 3, 5)
10% non collagenous proteins
makes the scaffold upon which HA crystals are laid down

Question 3

non collagenous proteins in dentin

Answer 3

Dentin matrix protein 1- DMP1
dentin sialophosphoprotein (DSPP)

Question 4

DSSP cleaved to

Answer 4

DSP DGP and DPP

Question 5

dentin sialoprotein

Answer 5

DSP
proteogycan
expressed in tubules
may act to prevent minerlaization
similar to dmp-1
problems can causae dentinogenesis imperfecta types 2&3
(type one defect in collagen-pulp filled with abnormal dentin)
(type 2 dssp defect, same result)
(type 3 enlarged hypomineralized puld chambers)

Question 6

DGP

Answer 6

dentine glycoprotein

unknown function, possibly biominerlaization

Question 7

DPP

Answer 7

dentin phosphoprotein
binds a lot of Ca 2+, intitates HA formation
attached to collagen
not thought to be glycosylated

Question 8

dentin pulp complex

Answer 8

arises from dental papilla
initial differentiation comes from critical interaction with the IEE
odontoblasts differentiate and fill the acellular zone between IEE and dental papilla
provides vascular support to developing OD

Question 9

DEJ

Answer 9

scalloped to help interlock

shape defines crown shape and keeps dentic directly attached to enamel during loading

Question 10

von korffs fibers

Answer 10

.2 mm collagen type 3 fibers associated with fibronectin

Question 11

dentin formation

Answer 11

extends towards the IEE and developing OD extends tomes fibers (process) into developing matrix and secreting dentin matrix components
starts as predentin then gets mineralized
globular is mantle

Question 12

tomes fiber

Answer 12

what gets left behind by OD- future OD process

Question 13

stages

Answer 13

first globular, secreted matrix vesicles releases matrix crystals
non collagenous matrix proteins regulate sebsequent dentin formation resulting in tubular primary dentin

Question 14

root dentin

Answer 14

hertswig root sheaths initiates odontoblast differentiation

mainly just anatomical differences, mingling of dentin collages with cememntum collagen

Question 15

primary dentin

Answer 15

mantle dentin and initial deposition of circumpulpal dentin

Question 16

secondary dentin

Answer 16

tubular dentin laid down subsequent to root formation, histologically distinct from primary
coronal dentin is sigmoidal

Question 17

tertiary dentin

Answer 17

response to insult
reactionary- trauma doesnt damage OD
reparative- trauma damaged OD

Question 18

dentin macrostructure

Answer 18

more compact at pulp

surrounded by collars of highly calcified peritubular dentin

Question 19

sclerotic dentin

Answer 19

occluded tubules
occurs naturally with age
starts apically and moves coronal

Question 20

interglobular dentin

Answer 20

hypomineralized dentin
formed when fusion of mineral containing vesicles fail
can be associated with vitamin D deficiency or flourosis
most common near mantle dentin

Question 21

cyclic depostion of primary dentin

Answer 21

4 micrometers a day
every five days or so (20 Micro) there is a noticeably different orientation of collaged (lines of von ebner)
mineralization about 4 micrometers a day
secondary dentin is slower

Question 22

contour lines of owen

Answer 22

enhanced lines that indicate diruption of tooth formation (neonatal line)
equivalent to straie of retzius

Question 23

granular layer of tomes

Answer 23

root dentin
funny looking dots around roots
gets more granular towards apex
possibly:
a) hypomineralized areas of dentin, similar to interglobular dentin
b) part of looped dentinal tubules (artifact of sectioning)
c) specialized structures which help form d-c junction